Systems and methods related to heat pumps with adsorbent

Abstract

Some aspects of the present disclosure are related to systems for efficiently conditioning air for a space to be conditioned. In some embodiments, the systems cool and dehumidify air. In some embodiments, the systems include an adsorbent device, for example, a desiccant wheel, to dehumidify air, which is arranged with heat exchangers. In some embodiments, the systems produce supply air having a dew point temperature below that of an operating temperature of a cooling heat exchanger. In some instances, the desiccant wheel comprises a desiccant comprising a metal organic framework (MOF) which facilitates operation of a heating heat exchanger for regenerating the desiccant a low temperature. The systems described herein may further include other features that improve efficiency of the system during operation, in accordance with some embodiments. Still other aspects are generally related to methods, kits, or the like.

Description

[0001] SYSTEMS AND METHODS RELATED TO HEAT PUMPS WITH ADSORBENT

[0002] RELATED APPLICATIONS

[0003] This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application No. 63 / 662,374, filed June 20, 2024, and entitled “SYSTEMS AND METHODS RELATED TO HEAT PUMPS WITH ADSORBENT,” which is incorporated herein by reference in its entirety for all purposes.

[0004] FIELD OF THE INVENTION

[0005] The present invention relates to systems and methods to provide heating, cooling, and / or dehumidification to a space.

[0006] BACKGROUND OF THE INVENTION

[0007] The rising demand for cooling is putting strain on power supply, grid infrastructure, etc. Meeting the world’s demand for cooling will be one of the defining challenges of our time. This challenge can be addressed by redesigning today’s air conditioning systems to take advantage of new materials and processes.

[0008] Many conventional vapor-compression based air conditioning systems provide cooling and dehumidification by passing air over a cooling coil which is maintained at a lower temperature than the air by the flow of refrigerant through the coil. Sensible cooling is achieved by passing air over a cooling coil which is cooler than the entering air, resulting in heat transfer from the air to the refrigerant and reducing the temperature of the air. Latent cooling, or dehumidification, is achieved by passing air over a cooling coil which is below the dewpoint of the entering air. This results in moisture from the air forming condensate on the coil surface and transferring the latent heat of vaporization to the refrigerant. In such systems, sensible and latent heat removal are coupled such that either sensible or latent cooling can be controlled, but not both. Furthermore, to meet high latent loads the cooling coil must operate at very low temperatures, resulting in poor efficiency of the vapor compression system.

[0009] SUMMARY OF THE INVENTION Systems and methods to provide conditioning of air, e.g., heating, cooling and dehumidification to a space as generally described. The subject matter of the present disclosure involves, in some cases, interrelated products, alternative solutions to a particular problem, and / or a plurality of different uses of one or more systems and / or articles.

[0010] Some aspects are related to methods.

[0011] In some embodiments, the method is a method of conditioning air for a space to be conditioned. In some embodiments, the method comprises contacting air from a process stream with a cooling heat exchanger and then a process portion of a desiccant wheel to form supply air to the space to be conditioned; contacting air from the space to be conditioned with a first heating heat exchanger and a regeneration portion of the desiccant wheel; and contacting air from an auxiliary stream with a second heating heat exchanger, wherein a dew point temperature of the supply air is less than or equal to a temperature of the cooling heat exchanger, and a temperature of the first heating heat exchanger is less than or equal to 60 degrees C.

[0012] In some embodiments, the method comprises contacting air from a process stream with an evaporator and then a process portion of a desiccant wheel to form supply air to be delivered to a space to be conditioned; and contacting air from the space to be conditioned with a condenser and then a regeneration portion of the desiccant wheel, wherein a dew point temperature of the supply air is less than or equal to a temperature of the evaporator, and a temperature of the condenser is less than or equal to 60 degrees C.

[0013] In some embodiments, the method comprises contacting air from a process stream with a cooling heat exchanger and a process portion of a desiccant wheel having an integrated seasonal moisture removal efficiency of at least 8 Ibs / kWh according to AHRI920-2020 edition (ISMRE2) to form supply air to the space to be conditioned; and contacting air from the space to be conditioned with a heating heat exchanger and a regeneration portion of the desiccant wheel.

[0014] In some embodiments, the method comprises flowing air through a process air stream such that at least a portion of the air contacts a cooling heat exchanger and then a process portion of a desiccant wheel to form supply air to the space to be conditioned; flowing air through a regeneration air stream such that at least a portion of the air contacts a heating heat exchanger and then a regeneration portion of the desiccant wheel; and flowing at least a portion of the air of the regeneration air stream through a bypass conduit such that the air does not contact the heating heat exchanger or the regeneration portion of the desiccant wheel, wherein a dew point temperature of the supply air is less than or equal to a temperature of the cooling heat exchanger, and a temperature of the heating heat exchanger is less than or equal to 60 degrees C.

[0015] Some aspects are related to systems.

[0016] In some embodiments, the system is a system for conditioning air. In some embodiments, the system comprises a first conduit defining a process air pathway and a second conduit defining a regeneration air pathway; a refrigeration circuit comprising a condenser and an evaporator; and a desiccant wheel having a process portion and a regeneration portion, wherein a process air stream flowing through the process air pathway enters the first conduit, directly contacts at least a portion of the evaporator, and then contacts the process portion of the desiccant wheel, and a regeneration air stream flowing through the regeneration air pathway enters the second conduit, directly contacts at least a portion of the condenser, and then contacts the regeneration portion of the desiccant wheel.

[0017] In some embodiments, the system comprises a first conduit defining a process air pathway and a second conduit defining a regeneration air pathway; a refrigeration circuit comprising a heating heat exchanger and a cooling heat exchanger; and a desiccant wheel having a process portion and a regeneration portion, wherein the second conduit comprises a bypass segment bypassing the heating heat exchanger and / or the desiccant wheel.

[0018] In some embodiments, the system comprises a first conduit defining a process air pathway and a second conduit defining a regeneration air pathway; a first refrigeration circuit comprising a first heating heat exchanger and a first cooling heat exchanger; a second refrigeration circuit comprising a second heating heat exchanger and a second cooling heat exchanger; and a desiccant wheel having a process portion and a regeneration portion, wherein a process air stream flowing through the process air pathway enters the first conduit, contacts at least a portion of the first cooling heat exchanger, contacts the process portion of the desiccant wheel, and contacts at least a portion of the second cooling heat exchanger, and a regeneration air stream flowing through the regeneration air pathway enters the second conduit, contacts at least a portion of the first heating heat exchanger, contacts the regeneration portion of the desiccant wheel, and contacts at least a portion of the second heating heat exchanger.

[0019] In some embodiments, the system comprises a process air pathway having a process airflow direction; a regeneration air pathway having a regeneration airflow direction; a condenser; an evaporator; and a desiccant wheel positionable with a portion in the process air pathway and a portion in the regeneration air pathway, wherein: the process air pathway, in the process airflow direction, first contacts at least a portion of the evaporator and then contacts a portion of the desiccant wheel, and the regeneration air pathway, in the regeneration airflow direction, first contacts at least a portion of the condenser, and then contacts a portion of the desiccant wheel.

[0020] Other advantages and novel features of the present disclosure will become apparent from the following detailed description of various non-limiting embodiments of the disclosure when considered in conjunction with the accompanying figures. In cases where the present specification and a document incorporated by reference include conflicting and / or inconsistent disclosure, the present specification shall control.

[0021] BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Non-limiting embodiments of the present disclosure will be described by way of example with reference to the accompanying figures, which are schematic and are not intended to be drawn to scale unless otherwise indicated. In the figures, each identical or nearly identical component illustrated is typically represented by a single numeral. For purposes of clarity, not every component is labeled in every figure, nor is every component of each embodiment of the disclosure shown where illustration is not necessary to allow those of ordinary skill in the art to understand the disclosure. In the figures:

[0023] FIG. 1 shows a schematic illustration of an example system, according to some embodiments; FIG. 2 shows a schematic illustration of an example system, according to some embodiments;

[0024] FIG. 3A shows a schematic illustration of an example system, according to some embodiments;

[0025] FIG. 3B shows a block diagram of the refrigerant circuits of the system depicted in FIG. 3 A, according to some embodiments;

[0026] FIG. 4 shows a psychrometric chart associated with operating a system as described herein, according to some embodiments;

[0027] FIGS. 5A-5F show schematic illustrations of example systems, according to some embodiments; and

[0028] FIG. 6 is a plot showing the moisture removal efficiency of an example systems, according to some embodiments.

[0029] DETAILED DESCRIPTION

[0030] This disclosure relates to unique components and methodologies, and in some cases unique combinations of components and methodologies that may have been used in known systems. Where a particular component or act is described herein, it is to be understood it can be used in combination with any other component or act described herein even if that specific arrangement is not precisely described or shown. I.e., it is within the scope of this disclosure to make any combination of any components or methodologies described herein. It is also to be understood that components and methodologies described herein are by way of example only, and can be modified, while still falling within the scope of this disclosure.

[0031] For example, air streams and conduits are described. Sometimes, air streams of this disclosure can be directed through conduits, but it is within the scope of this disclosure that air streams can be propelled for interaction with various components without necessarily being confined or otherwise directed or affected by a conduit. Where conduits are used, those of ordinary skill in the art can select any dimension of conduit including length, cross-sectional dimension, cross-sectional area, shape, and / or any material suitable for constructing a conduit for any particular purpose. Supply air and air streams, and regeneration air and air streams are described. In general, but not exclusively, supply air is for delivery to a space to be conditioned, and regeneration air is for regenerating a desiccant (e.g., driving at least some moisture off a desiccant), and / or offloading heat from a system. But those of ordinary skill in the art will recognize that arrangements described herein using supply air and / or regeneration air can be modified and applied to the movement, control, and / or manipulation of other volumes of air and / or air streams for other purposes, which can optionally benefit from other components and methodologies described herein.

[0032] In many examples, methodologies involve a particular volume of air and / or air stream contacting a system component. In one set of embodiments this means that at least a portion of the air flows over at least a portion of at least one surface of the component. Those of ordinary skill in the art will recognize that there are other ways to achieve the same or a similar result, all of which fall within the definition of “contacting” in this context, i.e., thermally contacting (interacting in any way to transfer heat between the component and the air). For example, if an air stream is described as contacting a component and thereby being cooled, where the component removes heat from the air, it is to be understood that this result can be achieved, within the scope of this disclosure, with alternative arrangements including, for example, intermediate components. E.g., a component arranged to remove heat from an air stream can be separated from that air stream by one or more other components, layers, heat transfer elements, or volumes of air or other gases (e.g., air streams) that serve to transfer heat from the air stream to the component. The same can be the case where heat is transferred from a component to an air stream, i.e., intermediate materials, components, or gas (e.g., air) volumes / streams can be present.

[0033] Heaters and coolers are described herein, and it is to be understood that in one set of embodiments any type of heater and / or cooler can be used. Examples of heaters include resistive coils, conduit carrying a heating fluid, exothermic chemical reacting materials, burners, or any other component that can generate heat. In many embodiments, the heater is a condenser, such as are known in the field of HVAC, the construction and operation of which can be selected by those of ordinary skill in the art in a variety of ways. Coolers can similarly be provided from among a number of options, including conduits carrying a cooling fluid, an endothermic melting, subliming, or other reaction, or the like. In many embodiments, the cooler is an evaporator, the construction and operation of which can be selected by those of ordinary skill in the art in a variety of ways.

[0034] HVAC circuits, or refrigeration circuits, are described in some portions of this disclosure. The design and selection of such circuits, including selection of refrigerants, conduits, condensers, evaporators, and / or any other components is well within the level of ordinary skill in the art, and any combination of components and methodologies can be used to meet the goals of the described process, or a process modified beyond what is described herein.

[0035] Desiccants are described in many embodiments. As outlined further below, any of a number of desiccants can be selected. Desiccants can be self-supporting, and / or can be provided on a substrate which itself is typically not a desiccant. In many embodiments described herein, the substrate can be moved relative to one or more air streams such that an air stream, if held stationary (such air streams often can optionally themselves move if desired) ) contacts different portions of the substrate (or contacts different portions of a coating on the substrate such as a desiccant) depending upon the position of the substrate. In these embodiments, these substrates can be a movable belt, can take a rotational form such as a cylinder or wheel, or can be constructed in any manner so as to itself be moved relative to an air stream, e.g., moved into and out of an air stream, and / or where at least a portion of it is moved in or out of at least a portion of an air stream. As an example of the description above where any components or methodologies described herein can be substituted with others described herein or others within the ability of those of ordinary skill in the art to use, where a desiccant wheel is described herein, it is to be understood that any other movable desiccant or desiccant-carrying substrate can be used.

[0036] More specifically, some aspects of the present disclosure are related to systems for efficiently conditioning air for a space to be conditioned. In some embodiments, the systems cool and dehumidify air. In some embodiments, the systems include an adsorbent device to dehumidify air, for example, a desiccant wheel, which is arranged with heat exchangers. In some embodiments, the systems produce supply air having a dew point temperature below that of an operating temperature of a cooling heat exchanger. In some instances, the desiccant wheel comprises a desiccant comprising a metal organic framework (MOF) which facilitates operation of a heating heat exchanger for regenerating the desiccant a low temperature. The systems described herein may further include other features that improve efficiency of the system during operation, in accordance with some embodiments. Still other aspects are generally related to methods, kits, or the like.

[0037] Typical systems for conditioning air do not include a desiccant and operate by transferring heat from air to be conditioned to a heat exchanger. When dehumidification is desired is such systems, a cooling heat exchanger is operated to cool the air until it is saturated with water, and then further cools the air to partially dehumidify it to a desired humidification level. Following dehumidification in this manner, the air is typically too cold to provide to the space to be conditioned, so a subsequent heating step will be performed to bring the air to the desired temperature of the supply air. Dehumidifying solely with a heat exchanger accordingly necessitates a large energy input to remove the moisture (e.g., via transferring latent heat) and to perform an additional heating step to bring the air the desired temperature and humidity. These steps decrease the efficiency of typical system.

[0038] Some previous systems utilizing desiccants overcome some of the abovedescribed issues, but typically utilized desiccants having high regeneration temperatures (e.g., greater than 70 degrees C). Accordingly, heating heat exchangers used to regenerate the desiccants were operated at high temperatures, which prevented efficient operation of the system. Moreover, high regeneration temperatures in previous systems were unsuitable for using certain desiccants such as MOFs, as the high temperatures may degrade the MOFs.

[0039] The present disclosure overcomes the disadvantages of the prior art by providing heating, cooling, and dehumidification of air at high efficiency.

[0040] Advantageously, the systems described herein include desiccants that may be used in combination with heat exchangers to decouple treatment of the sensible and latent heat loads of incoming air. For instance, heat exchangers may be used to remove a sensible heat load and a partial latent heat load, but the desiccants described herein may facilitate removal of a majority of a latent heat load. Thus, the systems described herein may lower the dew point temperature of treated air via dehumidification after cooling of the air at a heat exchanger. The use of desiccants in such a manner may obviate the need cool the air to perform the desired dehumidification, which required a subsequent heating step in typical systems. Accordingly, by lowering the dew point temperature of the air being processed at a desiccant, the systems described herein may operate cooling heat exchangers at a temperature that is higher than a dew point temperature of the supply air provided by the system.

[0041] In some embodiments, and as described in more detail elsewhere herin, the desiccants used in the present systems desirably comprise a metal organic framework (MOF), thereby allowing the use of a heating heat exchanger with a low temperature that is suitable for regenerating the MOF. In some embodiments, the heat for regenerating the MOF is provided as waste heat from a refrigerant circuit. Additionally, while some of the heat from the refrigerant circuit may be removed during regeneration of the MOF, the system may further include an auxiliary air stream and additional heating heat exchanger to remove heat from the refrigerant circuit. This additional heating heat exchanger may provide for efficient operation of the refrigerant circuit, as the compressor of the refrigerant circuit does not need to do as much work to cool the refrigerant within the refrigerant circuit as in instances where the additional heating heat exchanger and / or auxiliary air stream are absent.

[0042] Moreover, as noted above, MOFs were generally incompatible with previous systems, but the systems described herein operate in a manner to avoid degradation of the MOF. For instance, regeneration temperatures are generally low (e.g., less than or equal to 60 degrees C, etc.). Additionally, some aspects are generally related to adsorbent devices that are easily replaceable in whole and / or in part. For instance, in some embodiments, a desiccant wheel comprising a MOF (e.g., a degraded MOF) may be removed from a system and replaced with a second desiccant wheel comprising a MOF (e.g., a non-degraded MOF). In some embodiments, only a portion of the desiccant wheel may be replaced, e.g., if only that portion contains degraded MOF.

[0043] In some embodiments, the system comprises a heat pump comprising at least one refrigerant circuit configured to transfer heat from one airstream to another and a desiccant device configured to transfer moisture from one airstream to another. In some embodiments, the refrigerant circuit comprises at least one compressor, which may be configured to operate at a single speed, more than one speed, or be controllable to a range of speeds by an inverter drive or other methods known to those skilled in the art. In some embodiments, the systems and methods described herein describe a heating heat exchange and a cooling heat exchanger, and the systems and methods are generally directed to cooling and / or dehumidifying air to provide to a space to be conditioned. It will be understood that the heating heat exchange and a cooling heat exchanger are part of a heat pump which may facilitate switching their operation (e.g., the cooling heat exchanger becomes a heating heat exchanger and the heating heat exchanger becomes cooling heat exchanger) such that the systems and methods are directed to heating and / or humidifying air to be provided to a space to be conditioned.

[0044] In some embodiments, the refrigerant circuit comprises one or more heat exchangers. In some embodiments, the one or more heat exchanger comprise a heating heat exchanger and / or a cooling heat exchanger. In some embodiments, the heating heat exchanger is a heating coil. The heating heat exchanger may be any of a variety of suitable heaters, in accordance with some embodiments. For instance, in some cases, the heating heat exchanger comprises a direct expansion heat exchanger, a hot water heat exchanger, an electrical resistance heater, a condenser, and / or an indirect or direct gas heater. In some embodiments, the heating heat exchanger comprises or is a condenser. Other heating heat exchangers are also possible. In accordance with some embodiments, the cooling heat exchanger may be a cooler. In some embodiments, the cooling heat exchanger may be any of a variety of suitable coolers. For example, in some cases, the cooling heat exchanger comprises a direct expansion heat exchanger, an evaporator, and / or a water chiller. In some embodiments, the cooling heat exchanger comprises or is an evaporator. Other cooling heat exchangers are also possible.

[0045] As noted above, in some embodiments, the systems described herein may include an adsorbent device. An adsorbent device is used to transfer moisture from one airstream to another, in accordance with some embodiments. In accordance with some embodiments, the adsorbent device comprises a desiccant wheel. In some embodiments, the adsorbent device comprises a process section in which moisture is transferred from the air to the adsorbent and a regeneration section in which moisture is transferred from the adsorbent to the air. For instance, in some embodiments, the adsorbent device comprises or is a desiccant wheel that includes a process section and a regeneration section. It will be understood that a process section and a regeneration section of a desiccant wheel or other absorbent device are not static positions on the wheel and are related to portions of the wheel or device through which an airstream may pass to condition the air and / or to regenerate the wheel. As a non-limiting example, a process airstream may be positioned to pass through a process section of a desiccant wheel and a regeneration airstream may be positioned to pass through a regeneration section of the desiccant wheel, while the desiccant wheel is positionable (e.g., rotatable) such that different portions of the wheel may be aligned with the process airstream and or the regeneration airstream at different times. Additionally, while described in the context of a desiccant wheel, it will be understood that a process section and / or regeneration section of an adsorbent device may not be static with relation to the process and / or the regeneration airstream.

[0046] In some embodiments, the systems described herein include a blower. In some embodiments, the blower is used to move air into and / or through one or more conduits of the system. In some embodiments, the blower comprises a fan. In some embodiments, the blower comprises an axial fan and / or a centrifugal fan. In some embodiments, different blowers are used to move air to and / or from different spaces. For instance, in some embodiments, an axial fan may be used to move outdoor air (OA). In some embodiments, a centrifugal fan may be used to move supply air (SA) and / or exhaust air (EA). It is also possible to use the same type or different types of blowers for different air streams, in accordance with some embodiments. In some embodiments, fans are used to move air across the cooling heat exchangers, the heating heat exchangers, and / or the adsorbent device(s), and / or energy recovery device(s), and / or through bypass conduits. In some embodiments, fans are used to move air across the evaporators, the condensers, and / or the adsorbent device.

[0047] In some embodiments, the adsorbent device may be a wheel, drum, or belt driven system. In some embodiments, adsorbent material is incorporated into the adsorbent device in such a way that a high surface area of adsorbent is exposed to airflow passed through the device. In some embodiments, the adsorbent may be coated onto a substrate, embedded into a substrate, or formed into a monolith structure by additive manufacturing, extrusion, or other methods. In some embodiments, the desiccant can comprise any acceptable material, or combination of materials, including at least one of silica gel, alumina, zeolite, activated carbon, or metal organic framework (MOF) material. In some embodiments, the desiccant comprises a MOF. Non-limiting examples of MOFs that may be used on the adsorbent devices described herein include Aluminum Fumarate, MIL-100, MIL-101, CAU-10, CAU-23, MIL-53, MIL-68, ZIF-8, ZIF-90, and / or MOF-303. In some embodiments, the MOF comprises MIL-lOl(Cr) and / or MIL- 100(Fe). Other MOFs are also possible. It will be understood that the MOF or other desiccant is generally configured to remove moisture from an airstream (i.e., adsorb the moisture from the airstream) within a process airstream, and the MOF or other desiccant may regenerate by being heated to remove the moisture (i.e., desorb) from the MOF or other desiccant.

[0048] In some embodiments, the formulation may comprise a metal organic framework (MOF). As used herein, “MOF” is given its ordinary meaning in the art and refers to a one-, two-, or three-dimensional coordination polymer including metal atoms (e.g., metal ions) and ligands which function as organic structural units, wherein a portion of the metal atoms are each chemically bonded to at least one bi-, tri-, or poly-dentate organic structural unit. The metal atoms, in addition to being coordinated with at least one ligand, may also be bound to one or more auxiliary ligands. In some embodiments, the MOFs may be used as desiccants, or materials suitable for adsorbing water as a function of the partial pressure of water and / or water vapor in the atmosphere. The MOFs used herein, in accordance with some embodiments, may have an adsorption capacity for water and / or water vapor, and those of ordinary skill in the art will know how to appropriately select MOF materials for use in the systems and methods disclosed herein.

[0049] In some embodiments, it is desirable to use a MOF due to a high adsorption capacity, steep adsorption isotherms, and low regeneration temperatures. Despite these advantages, previous systems did not typically include MOFs, as the MOFs are subject to degradation under typical operating conditions in previous systems. Advantageously, the systems and methods described herein are designed to avoid degradation of the MOF, when used, for instance, by operating under certain conditions such as... In some embodiments, for instance when the desiccant comprises a MOF (e.g., a desiccant wheel comprising a MOF), the heat needed to regenerate the desiccant is low compared to adsorbent devices comprising typical desiccant materials such as silica gels or alumina. Accordingly, in some embodiments, a temperature to regenerate the MOF is less than or equal to 60 degrees C, less than or equal to 55 degrees C, less than or equal to 50 degrees C, less than or equal to 45 degrees C, or less than or equal to 40 degrees C and / or greater than or equal to 35 degrees C or greater or equal to 30 degrees C.

[0050] In some embodiments, the systems described herein may include one or more energy recovery ventilators (ERVs). In some embodiments, the ERV may be constructed in a similar manner to the adsorbed device, e.g., a wheel structure having a first portion positioned in a process air pathway and a second portion positioned in a regeneration air pathway. In some embodiments, the ERV functions to transfer heat between the process air stream and regeneration air stream during system operation. For instance, in some cases, the ERV is configured such that a portion thereof is cooled by the regeneration air stream (e.g., when the regeneration air stream is sourced from the space to be conditioned), effectively heating the regeneration air stream. After being cooled by the regeneration air stream, the ERV rotates such that the cooled portion of the ERV cools the process air stream. In this manner, the ERV transfers heat between air streams, in some cases, and thereby may desirably recover energy from exhaust air from the room to be conditioned and reduce a load on the system. Accordingly, in some cases, the ERV comprises a thermally conductive material. Non-limiting examples of suitable materials for the ERV include aluminum, stainless steel, or copper. Other materials are also possible. In some embodiments, the ERV may further include a desiccant coating. In other embodiments, a desiccant is absent from the ERV. In some embodiments, an ERV may advantageously be utilized in a system when incoming air to be processed comprises a low humidity, e.g., during colder seasons, as the latent heat load to be processed of the incoming air is low and thus it may be advantageous to lessen or avoid using the adsorbent device to prolong its lifetime.

[0051] The systems described herein, in some embodiments, may include one or more refrigerant circuits. The refrigerant circuits may allow for heat transfer to and / or from certain airstreams, thus facilitating the conditioning of the airstreams, in some embodiments. In some embodiments, a refrigerant circuit may include one or more heating heat exchangers, one or more cooling heat exchangers, a heat pump, and / or one or more metering devices. In some instances, a system may include a refrigerant circuit including a first cooling heat exchanger, a second cooling heat exchanger, a first heating heat exchanger, and a second heating heat exchanger. In some instances, a system may include a first refrigerant circuit including a first cooling heat exchanger and a first heating heat exchanger, and a second refrigerant circuit including a second cooling heat exchanger and a second heating heat exchanger. In some embodiments, the system comprises a refrigeration circuit comprising a heating heat exchanger comprising a condenser and a cooling heat exchanger comprising an evaporator.

[0052] As described above, the system may include a first heating heat exchanger and a second heating heat exchanger. In some embodiments, the first heating heat exchanger may heat air within a regeneration air stream such that the air may be sufficiently hot to regenerate a portion of an adsorbent device (e.g., a desiccant wheel). In some embodiments, the first heating heat exchanger may be configured to use waste heat from the refrigerant circuit to regenerate at least a portion of the the adsorbent device. In some instances, a second heating heat exchanger may be positioned within a conduit defining an auxiliary air stream as described in more detail elsewhere herein. In some embodiments, the second heating heat exchanger may be considered an auxiliary heat exchanger and / or a primary heat exchanger, as it may be configured to remove a majority (e.g., at least 50%, at least 60%, at least 70%, or at least 80% and / or up to 90% or up to 100% of the heat removed from the refrigerant circuit is rejected through the second heating heat exchanger) of heat from a refrigerant circuit. In some embodiments, the first heating heat exchanger and the second heating heat exchanger are positioned in series on a single refrigeration circuit. In some embodiments, the first heating heat exchanger and the second heating heat exchanger are positioned on separate refrigeration circuits. It will be understood that additional heating and / or cooling heat exchangers are also possible.

[0053] In some embodiments, one or more heating heat exchangers and / or one or more cooling heat exchangers may be in fluidic communication with one or more portions of an adsorbent device (e.g., a desiccant wheel). Fluidic communication, in accordance with some embodiments, is established through one or more conduits. For instance, in some embodiments, the systems described herein may include one or more conduits. In some instances, the system includes a conduit defining a process air pathway. In some instances, the system includes a conduit defining a regeneration air pathway. In some instances, the system includes a first conduit defining a process air pathway and a second conduit defining a regeneration air pathway. In some embodiments, the conduit defining the process air pathway is configured such that a process air stream may flow through an inlet into the conduit in a process airflow direction, directly contact at least a portion of a cooling heat exchanger, and then contact the process portion of the desiccant wheel. In some embodiments, air passing through the conduit defining the process air stream may then pass through a second cooling heat exchanger and / or an outlet into a space to be conditioned. Accordingly, in some embodiments, there may fluidic communication between an inlet of the conduit defining the process air stream, a first cooling heat exchanger, a process portion of the desiccant wheel, a second cooling heat exchanger, and / or an outlet of the conduit defining the process air stream.

[0054] As used herein, two elements are in “fluidic communication” with each other (or, equivalently, in fluid communication with each other) when fluid may be transported from one of the elements to the other of the elements without otherwise altering the configurations of the elements or a configuration of an element between them (such as a valve). Two conduits connected by an open valve (thus allowing for the flow of fluid between the two conduits) are considered to be in fluidic communication with each other. In contrast, two conduits separated by a closed valve (thus preventing the flow of fluid between the conduits) are not considered to be in fluidic communication with each other.

[0055] In accordance with some embodiments, the conduit defining the regeneration air pathway is configured such that a regeneration air stream may flow through an inlet into the conduit in a regeneration airflow direction, directly contact at least a portion of a heating heat exchanger, and then contact the regeneration portion of the desiccant wheel. In some embodiments, air passing through the conduit defining the regeneration air pathway may then pass through an exhaust outlet. Accordingly, in some embodiments, there may fluidic communication between an inlet of the conduit defining the regeneration air pathway, a heating heat exchanger, a regeneration portion of the desiccant wheel, and / or an outlet of the conduit defining the process air stream. The system may further include one or more bypass segments of one or more conduits, in accordance with some embodiments. A bypass segment, in some embodiments, may be configured to bypass at least a portion of one or more components in fluidic communication with a main conduit (e.g., a conduit defining a process air stream and / or a conduit defining a regeneration air stream). For instance, a bypass segment may provide fluidic communication between a first position within a primary conduit (e.g., a conduit defining a process air pathway or a conduit defining a regeneration air pathway) and a second position within the primary conduit, circumventing the portion of the primary segment between the first and second positions. In this manner, air flowing through the bypass segment may not contact an element within the primary conduit associated with the bypass segment, such as a portion of a desiccant device or a heat exchanger. Accordingly, it will be understood that a bypass segment may comprise a conduit providing an alternative route for an airstream to flow, relative to a main air flow pathway (e.g., through a process air pathway or a regeneration air pathway). In some embodiments, a conduit defining a process air stream comprises a bypass segment. In some embodiments, a conduit defining a regeneration air stream comprises a bypass segment. In some embodiments, air flowing through a bypass segment does not contact a heating heat exchanger in the associated main conduit. In some embodiments, air flowing through a bypass segment does not contact a cooling heat exchanger in the associated main conduit. In some embodiments, air flowing through a bypass segment does not contact the portion of the adsorbent device (e.g., desiccant wheel) in the associated main conduit. In some embodiments, air flowing through a bypass segment does not contact the portion of the adsorbent device (e.g., desiccant wheel) or a heating heat exchanger in the associated main conduit. In some embodiments, air flowing through a bypass segment does not contact the portion of the adsorbent device (e.g., desiccant wheel) or a cooling heat exchanger in the associated main conduit.

[0056] In some embodiments, the bypass segment may modulate an amount of air flowing over and / or through a component of the system. For instance, a bypass segment may bypass a heating heat exchanger, in some cases. In some embodiments, the bypass segment may lessen the amount of air flowing over the heating heat exchanger, e.g., by diverting air flow through the bypass segment from the associated main conduit. In some such cases, this may allow the heating heat exchanger to operate at a higher temperature at a given heating capacity compared to if more air was flowed over and / or through the heating heat exchanger being operated at the same heating capacity. Accordingly, air contacting the heating heat exchanger may be heated to higher temperatures when the bypass segment diverts at least a portion of an air stream from the main conduit (e.g., a conduit defining a process air pathway or a conduit defining a regeneration air pathway) and the heating heat exchanger is operated at the same heating capacity, thereby facilitating more efficient regeneration of a desiccant wheel downstream of the heating heat exchanger.

[0057] In some embodiments, the systems described wherein further include a conduit defining an auxiliary air pathway. The conduit defining an auxiliary air pathway may be separate from the conduit defining the process air pathway and / or the conduit defining the regeneration air pathway, in accordance with some embodiments. In some embodiments, the conduit defining an auxiliary air pathway provides fluidic communication between an inlet of the conduit defining the auxiliary air pathway, a heat exchanger (e.g., a second heating heat exchanger as described above) within the conduit defining the auxiliary air pathway, and an outlet of the conduit defining the auxiliary air pathway. In some such embodiments, the conduit defining an auxiliary air pathway is configured such that an auxiliary air stream flowing therethrough enters the conduit defining the auxiliary air pathway through the inlet, contacts at least a portion of the heat exchanger (e.g., a heating heat exchanger, a second heating heat exchanger, and / or an auxiliary heat exchanger), and then exits the conduit defining the auxiliary air pathway through the outlet. In some embodiments, the heat exchanger associated with the conduit defining the auxiliary air pathway facilitates removal of heat from one or more refrigeration circuits. In some embodiments, the conduit defining the auxiliary air stream is appropriately sized and arranged with one or more blowers to facilitate a volumetric flow rate of an airstream therethrough that is higher than the volumetric flow rate through other portions of the system (e.g., a process or regeneration air stream) during operation to facilitate heat transfer to or from a heat exchanger contained therein. In some embodiments, a volumetric flow rate through the auxiliary air stream is greater than or equal to the volumetric flow rate of the same as a process or regeneration air stream, greater than or equal to 1.5 times, or greater than or equal to 2 times and / or less than or equal to 2.5 times or less than or equal to 3 times the volumetric flow rate of the same as a process or regeneration air stream.

[0058] The conduits of the system may be arranged such that one or more inlets or outlets of the conduits are positioned within any suitable space, in some embodiments. For example, an inlet of a conduit of the system (e.g., a conduit defining a process air stream) may be positioned in an ambient environment (e.g., an outdoor environment, a space that does not contain conditioned air). In some embodiments, an inlet of a conduit of the system (e.g., a conduit defining a process air stream) may be positioned in a space to be conditioned, and may circulate air from the space to be conditioned. In some embodiments, air from either an ambient source and / or a space to be conditioned may be drawn into the system through one or more inlets, and may be selected based on the desired air conditions in the space to be conditioned. In some embodiments, an outlet of a conduit of the system (e.g., a conduit defining a regeneration air stream) may be positioned in an ambient environment (e.g., an outdoor environment, a space that does not contain conditioned air) to exhaust air therefrom. In some embodiments, an outlet of a conduit of the system (e.g., a conduit defining a process air stream) may be positioned in a space to be conditioned, and may provide supply air to the space to be conditioned.

[0059] In some embodiments, the systems described herein may include one or more sensors. For instance, in some embodiments, the system includes one or more temperature sensors. In some embodiments, the system includes one or more humidity sensors. In some embodiments, temperature and / or humidity sensors may be used to determine relative humidity and / or temperature of an incoming or outgoing air stream to and / or from the system. In some embodiments, temperature and humidity sensors may be used to determine an absolute humidity of an incoming and / or outgoing air stream to or from the system.

[0060] In some embodiments, a single refrigerant circuit includes a compressor, a first condenser, a second condenser, a first metering device, a second metering device, a first evaporator, and a second evaporator. Refrigerant is compressed by the compressor and discharged at a high temperature, high pressure state, in some embodiments. In some embodiments, the refrigerant passes through the first and second condenser and heat is transferred from the refrigerant to the air, resulting in phase change of the refrigerant from gas to liquid. In some embodiments, the refrigerant passes through at least one expansion device, resulting in a low pressure, low temperature state. In some embodiments, the refrigerant passes through the first and second evaporators and heat is transferred from the air to the refrigerant, resulting in phase change of the refrigerant from liquid to gas. In some embodiments, the refrigerant then returns to the suction side of the compressor.

[0061] The systems described herein may include a housing. In some embodiments, the housing may generally define an interior volume containing the adsorbent device, one or more conduits, heat exchangers, other components of the refrigerant circuit, and / or one or more blowers. The housing may include the inlets or outlets of the conduits, providing fluidic communication between an environment outside of the housing and the conduits contained within the interior volume of the housing.

[0062] FIG. 1 shows an illustrative embodiment of an example system 100 described herein. Outdoor air 101 passes through a filter 102, filtered air 103 passes through a first evaporator coil 104 pre-cooled air 105 passes through the process side of an adsorbent device 106 in the form of a wheel. Desirably, positioning a first evaporator coil 104 upstream of the process side of the adsorbent device 106 may increase a relative humidity of the air. For instance, lowering the temperature of the incoming air increases the relative humidity of the incoming air. In this manner, the adsorbent device 106 may remove to function in a more efficient manner, and the adsorbent device is configured to remove air from an air stream above a certain relative humidity.

[0063] Moisture in the air passes from the air to the adsorbent, which may be a MOF or other desiccant as described in more detail elsewhere herein. The air 107 then passes through a second evaporator coil 108. While optional, the addition of a second evaporator coil downstream of the process portion of the adsorbent device 106 allows the air to be cooled further once a desired humidity of the air is achieved. Conditioned air 109 passes through a supply fan 112 and is delivered as supply air to the conditioned space. Exhaust air from the conditioned space 113 passes through a filter 121 filtered air 122 passes through a first condenser 123 heated exhaust air 124 passes through the regeneration section of the adsorbent device 106. Air passes through exhaust fan 128 and is rejected outdoors 127. A compressor 115 pumps refrigerant through a refrigeration circuit of the system that connects the first evaporator coil, second evaporator coil, and first condenser, and a second condenser. Outdoor air 117 passes through a second condenser 116 to remove heat from the refrigeration circuit, and heated air 118 passes through a condenser fan 119 and is rejected outdoors.

[0064] FIG. 2 shows an illustrative embodiment including a first condenser labelled “cond 1”, a second condenser labelled “cond 2”, a first evaporator labelled “evap 1” and a second evaporator labelled “evap 2” and an adsorbent device embodied as a wheel labelled “wheel”. In a first airstream air passes through a first evaporator, then through an adsorbent device, then through a second evaporator and a first fan. In a second separate airstream air passes through a first condenser, then through an adsorbent device, then through a second fan. In a third airstream air passes through a second condenser and through a third fan. In one embodiment the second condenser is placed in the second airstream after the adsorbent device and sharing a common fan.

[0065] FIG. 3A shows another embodiment of a system 200. The system 200 includes a process air stream 202 defined by a conduit that provides fluidic communication between inlets 204 from an ambient atmosphere (e.g., an outdoor space), a first cooling heat exchanger 206, a process portion of an adsorbent device comprising a desiccant wheel 208, a second cooling heat exchanger 210, and an outlet 212 to a space to be conditioned. The conduit defining the process air stream 202 further includes a bypass segment to allow some of all of the process air stream 202 to bypass adsorbent device comprising the desiccant wheel 208 through a bypass airstream 214. The bypass segment may be open or closed, depending on the desired operation mode. The system 200 further includes a regeneration air pathway 220 defined by a conduit that provides fluidic communication between inlet 222 from a space to be conditioned, a heating heat exchanger 224, a regeneration portion of an adsorbent device comprising a desiccant wheel 208, and outlet 226 to an ambient atmosphere (e.g., an outside environment). The conduit defining the regeneration air pathway 220 further includes a bypass segment to allow some of all of the regeneration air pathway 220 to bypass the heating heat exchanger 224 and adsorbent device comprising the desiccant wheel 208 through a bypass airstream 228. Similarly to the bypass segment defining the bypass airstream 214 of the process air stream 202, the bypass segment defining the bypass airstream 228 of the regeneration air pathway 220 may be open or closed, depending on the desired operation mode. The second cooling heat exchanger and the heating heat exchanger (e.g., a first heating heat exchanger) are in thermal communication on a first refrigerant circuit. The system also includes a second refrigerant circuit that provides thermal communication between the first cooling heat exchanger and second heating heat exchanger (not shown) and an auxiliary conduit (not shown) defining an auxiliary air stream that passes through the second heating heat exchanger and is separate from the conduits defining the process and regeneration air streams. The second heating heat exchanger may remove most of the heat from the refrigerant circuit, in some embodiments. FIG. 3B shows a block diagram corresponding to the system 200 depicted FIG. 3A, and shows the first refrigerant circuit 230 providing thermal communication between the second cooling heat exchanger 210 and the first heating heat exchanger 224 and the second refrigerant circuit 231 providing thermal communication between the first cooling heat exchanger 206 and the second heating heat exchanger 232.

[0066] FIG. 4 shows a psychrometric chart illustrating a mode of operation of air being processed through system 200 of FIGS. 3A-3B. Initially, at point 1, ambient air is withdrawn through inlets 204 of system 200. The air is contacted with the first cooling heat exchanger 206 to cool the air to saturation, whereafter some moisture is removed through condensation at the cooling heat exchanger 206 to point 2. The air then contacts the process portion of the adsorbent device comprising a desiccant wheel 208 to further dehumidify the air to point 3. The air heats during the process due to the heat of adsorption released by the desiccant material (e.g., a MOF) at the adsorbent device comprising the desiccant wheel 208. From point 3 to point 4 on FIG. 4, the air is cooled at the second cooling heat exchanger 210 to a desired condition for the space to be conditioned. The air from point 4 is then provided to the space to be conditioned as supply air. In this operational mode, the operating temperature of the first cooling heat exchanger is above the dew point temperature of the supply air. It is also possible that the second cooling heat exchanger is unnecessary, and thus the process from step 3 to step 4 is omitted. In some such embodiments, the operating temperature of the first cooling heat exchanger (the only operating cooling heat exchanger) is above the dew point temperature of the supply air.

[0067] Referring again to FIG. 3A, system 200 includes a first refrigerant circuit 230 providing thermal communication between the first cooling heat exchanger 206 and the second heating heat exchanger (not shown in FIG. 3A), and a second refrigerant circuit 231 providing thermal communication between the second cooling heat exchanger 210 and the first heating heat exchanger 224. Including two refrigerant circuits allows one or the other refrigerant circuit to be toggled on or off while the maintaining the other refrigerant circuit on (e.g., the first refrigerant circuit continues operating while the second refrigerant circuit is toggled off). The inclusion of two refrigerant circuits requires an additional compressor for the second refrigerant circuit, but it may provide additional operational modes and / or improve efficiency of the system by allowing one of the circuits to be toggled off when unneeded. Alternative embodiments are also possible, for instance, an embodiment including a single refrigerant circuit thermally connecting the first and second cooling heat exchangers and the first and second heating heat exchangers, in some embodiments, is considered. Such an embodiment may provide a less complex system.

[0068] FIGS. 5A-5E show schematic diagrams of systems including various arrangements of refrigerant circuits and heat exchangers. In these systems, as well as the systems shown in FIGS. 1-3 and others described elsewhere herein, it will be understood that while described as heating and cooling heat exchangers, the heat exchangers are operated with a reversible heat pump so their function may switch (e.g., from a cooling heat exchanger to a heating heat exchanger and from a cooling heat exchanger to a heating heat exchanger) depending on a desired mode of operation.

[0069] FIG. 5A shows a system 300 including a first conduit 302 defining a process air stream 304 in which outside air (labelled OA, ambient air) contacts a first cooling heat exchanger 306, a process portion of a desiccant wheel 308, and a second cooling heat exchanger 310 before being provided to a space to be conditioned as supply air (SA). The system additionally includes a second conduit 312 defining a regeneration air stream 314 in which exhaust air (EA, from the space to be conditioned and / or an outdoor space) contacts a first heating heat exchanger and then a regeneration portion of the desiccant wheel 308 before being exhausted to an outdoor space. The system further includes an second heating heat exchanger 318 which is contacted with an auxiliary air stream 320 outside of both the conduits 302 and 312. The second heating heat exchanger 318 removes heat from the first refrigerant circuit 322 which thermally connects the first cooling heat exchanger 306 and the second heating heat exchanger 318. The second refrigerant circuit 324 thermally connects the second cooling heat exchanger 310 and the first heating heat exchanger 316. Each refrigerant circuit further includes a compressor 323 and a throttling device 325. System 300 further includes a bypass segment 326 of regeneration air stream 314, in which some of all of the air of the regeneration air stream may bypass the first heating heat exchanger and the regeneration portion of the desiccant wheel. While air may not be processed when passing through the bypass segment, it may provide ventilation to the space to be conditioned such that the space is not over pressurized. In some embodiments, when the adsorbent device is not active, the bypass segment may relieve a load on the blower of the corresponding conduit (e.g., defining the regeneration air pathway). It will be understood that, while the bypass segment 326 is depicted as bypassing heating heat exchanger 316 and the desiccant wheel 308 in conduit 312, alternative embodiments where bypass segment 326 bypasses only heating heat exchanger 316 or the desiccant wheel 308 are also contemplated.

[0070] FIGS. 5B-5D show similar embodiments as to that shown in FIG. 5 A, but with a few differences. The system 340 in FIG. 5B does not include a bypass segment associated with the regeneration air stream 314. Additionally, the first and second refrigerant circuits 322 and 324 of FIG. 5A are combined into a single refrigerant circuit 322 providing thermal communication between the first and second heating and cooling heat exchangers 306, 310, 316, and 318, which may be desirable in some cases due to a decrease in system complexity. In contrast, system 342 in FIG. 5C does not include the bypass segment associated with the regeneration air stream 314 and the second cooling heat exchanger 310 is upstream of the process portion of the desiccant wheel 308 in the process air stream 304, rather than downstream of the desiccant wheel 308. This may allow for additional cooling and / or dehumidification at the cooling heat exchangers 306 and 310 prior to dehumidification at the desiccant wheel 308. Moreover, while shown as two separate cooling heat exchangers 306 and 310 on two separate refrigerant circuits 322 and 324, it is also possible for the cooling heat exchangers 306 and 310 to be a single cooling heat exchanger having two inlets and two outlets providing fluidic communication with the refrigerant circuits 322 and 324. In some such embodiments, removal of a cooling heat exchanger downstream of the desiccant wheel in conduit 302 may reduce complexity of the system. Additionally, while not pictured with the bypass segment, an embodiment as shown in FIG. 5C but further including one or more bypass segments are also contemplated.

[0071] While the bypass segment 326 of the regeneration air stream 314 in FIG. 5A is absent in system 344 depicted in FIG. 5D, FIG. 5D further includes a third heating heat exchanger 328 downstream of the regeneration portion of the desiccant wheel 308 in the regeneration air stream 314. Accordingly, additional heat may be removed from the first refrigerant circuit 322 following regeneration of the desiccant wheel 308. Additionally, the air exiting the desiccant wheel 308 will be cooled by the desorption process and thus may more effectively facilitate removal of heat from the first refrigerant circuit. FIG. 5E is an arrangement generally similar to FIG.5A, but the system 346 does not include the auxiliary air stream 320 passing through the second heating heat exchanger 318. In contrast, the system 348 shown in FIG. 5E includes the second heating heat exchanger 318 downstream of the regeneration portion of the desiccant wheel 308. Removal of the auxiliary airstream may simplify the system, as there is no additional conduit for air flow outside of the process and regeneration airstreams.

[0072] FIG. 5F shows system 348 that is similar to system 340 shown in FIG. 5B, but further comprising ERV 330. The ERV is configured such that a portion thereof is cooled by the regeneration air stream (e.g., when sourced from the space to be conditioned), effectively heating the regeneration air stream. After being cooled by the regeneration air stream, the ERV rotates such that the cooled portion of the ERV cools the process air stream before the process air stream contacts the second cooling heat exchanger 310. Accordingly, the ERV may recover energy from exhaust air from the room to be conditioned, thereby reducing the load on the system.

[0073] In a first set of embodiments, the first and second evaporator and the first and second condenser are all part of a single refrigeration circuit with one compressor driving refrigerant flow through the coils. In some such embodiments, the system may advantageously include only a single compressor, reducing cost compared to when multiple compressors are present.

[0074] In a second set of embodiments, the first and second evaporator and the first and second condenser are split between more than one refrigeration circuits with more than one compressor driving refrigerant flow through the coils. In some such embodiments, the system may advantageously facilitate independent control of the refrigeration circuits. In some embodiments, one or more of the compressors may be turned off or modulated to a lower speed to conserve energy or otherwise enhance system operation. In some embodiments, one or more of the refrigerant circuits may be configured with an reversing valve allowing heat pump operation.

[0075] In some embodiments, the first and second condenser are configured in series such that refrigerant first passes through the first condenser and then through the second condenser. In some such embodiments, the order of the two condensers may be changed if advantageous. In some embodiments, the first and second condenser are configured in parallel such that the refrigerant flow splits before the condenser, refrigerant passes through both condensers, and then the refrigerant recombines after passing through the condensers. In some such embodiments, the mass flow of refrigerant passing through each of the two condensers may be modulated, or shut off entirely using combinations of electronic expansion valves, shutoff valves, TXVs or other devices known to those skilled in the art. More or less than two condensers may be used if advantageous, in some embodiments.

[0076] In some embodiments, the first and second evaporator are configured in series such that refrigerant first passes through the first evaporator and then through the second evaporator. In some such embodiments, the order of the two evaporators may be changed if advantageous. In some embodiments, the first and second evaporators are configured in parallel such that the refrigerant flow splits before the evaporator, refrigerant passes through both evaporators, and then the refrigerant recombines after passing through the evaporators. In some such embodiments, the mass flow of refrigerant passing through each of the two evaporators may be modulated, or shut off entirely using combinations of electronic expansion valves, shutoff valves, TXVs or other devices known to those skilled in the art. More or less than two evaporators may be used if advantageous, in some embodiments.

[0077] In some embodiments, the first and second evaporators are configured such that air first passes through the first evaporator, then passes through the process section of the adsorbent device, then passes through the second evaporator. The relative cooling capacities of the first and second evaporator may be controlled as necessary.

[0078] In some embodiments, the first and second condensers are configured such that air first flows through one condenser, then passes through the regeneration section of the desiccant device. The other condenser may be configured to take a separate airstream to reject heat from the system. This is advantageous because the physical size and airflow of the second condenser can be adjusted independently of the airflow through the adsorption device.

[0079] In some embodiments, the first and second condensers are configured such that air first flows through one condenser, then passes through the regeneration section of the adsorbent device, then passes through the second condenser. This is advantageous because it captures the efficiency benefit of desorption from the wheel, which lowers the air temperature and reduces the saturation temperature of the second condenser.

[0080] In some embodiments, the airflow through the regeneration section of the adsorbent device is the return air from the conditioned space. This airflow which is used to regenerate the adsorbent may also be outdoor air or a combination of return air and outdoor air. The relative ratio of outdoor air and return air may be specified by a controller and modulated through an actuated mixing baffle or other mixing device.

[0081] In some embodiments, the airflow through the process section of the adsorbent device is outdoor air. This airflow which is supplied to the conditioned space may also be return air from the conditioned space, or a combination of return air and outdoor air. The relative ratio of outdoor air and return air may be specified by a controller and modulated through an actuated mixing baffle or other mixing device.

[0082] In some embodiments, the adsorbent device comprises a wheel coated with metalorganic framework (MOF). The MOF may be regenerated at low temperatures due to its water uptake properties. Low regeneration temperatures of the MOF may provide for efficient operation of systems described herein, as regeneration may occur at lower temperatures than in typical systems that use conventional desiccants such as silica gels or alumina.. In some embodiments, the wheel is configured in the system such that air flows through the wheel substantially parallel to the rotational axis of the wheel. In some embodiments, the rotational axis of the wheel may not be substantially parallel with an air flow direction, for example, as the wheel may be tilted relative to the air flow direction. In some embodiments, the wheel is comprised of a substrate media such as honeycomb or corrugate forming channels for air to flow through. In some embodiments, airflow through the adsorbent device can be configured as parallel flow or counterflow. In some embodiments, the MOF may be regenerated at temperatures below 40 degrees C. In some embodiments, the process and regeneration sections of the wheel are divided by air seals. In some embodiments, the ratio of regeneration section face area to total face area of the wheel can range from 20-80%.

[0083] In some embodiments, at least some of the heat of the condenser coil is used to regenerate the adsorbent device. In some embodiments, the heat of the condenser coil is used to regenerate the adsorbent device. The device may be configured such that air heated by superheated compressor discharge refrigerant is directed to flow over a specific section of the adsorbent device. For example, discharge heated air may be directed in a horizontal linear region reaching from the inner hub to the outer rim of the wheel. In some embodiments, the wheel rotates, it sweeps through this region, so the full face of the wheel is exposed to it. The compressor discharge may be at a higher temperature than the saturation temperature of the refrigerant in the condenser. The hotter air heated by compressor discharge may be directed in a way which enables regeneration of the adsorbent at lower condenser temperatures. This is advantageous because lower condenser temperatures reduce the work of the compressor. The device may be configured such that the flow of refrigerant through the condenser is in counterflow to the rotational direction of the wheel. Higher temperatures may be achieved by other means in a local region to enhance regeneration of the adsorbent device, such as an electric resistance coil, PTC, or infrared heating element.

[0084] In some embodiments, the adsorbent device may be modulated to operate in either active dehumidification mode or passive dehumidification mode. In some such embodiments in which the adsorbent device is a wheel the operational mode can be modulated by wheel rotational speed. At high wheel speed the adsorbent device may act as a passive energy recovery device, transferring both sensible and latent energy. In passive dehumidification mode the compressor may be turned down or turned off. In some embodiments, at low wheel speed the adsorbent device acts as an active dehumidification wheel, using a heated airstream to regenerate the adsorbent. In other adsorbent device embodiments, such as a belt, the speed of the adsorbent movement between airstreams may be used to achieve transition between passive and active dehumidification.

[0085] In some embodiments the adsorbent device may be modulated to operate in active dehumidification mode, passive dehumidification mode, or other modes. A controller may be used to set the operating mode based on inputs including outdoor air conditions, indoor air conditions, predictive weather conditions, building loads, or inputs from other devices on a building management system (BMS) network. The controller may also modulate the rotational direction of the adsorbent device if advantageous.

[0086] In some embodiments, a sensible-only heat transfer device may be used to enhance performance of the adsorbent device by transferring heat between the process air stream and the ambient air. The sensible-only heat transfer device may be a rotary wheel, plate heat exchanger, run-around coil or other device.

[0087] In some embodiments the refrigerant system includes at least one four-way valve which may be actuated to facilitate heat pump operation modes. In heat pump operation mode, the supply air may be heated by the condenser coil. In certain embodiments, a four-way valve may be used to serve as a backup reheat mode to ensure supply air is delivered at desired temperature.

[0088] In some embodiments, the adsorbent device is a rotary wheel in which air passes through media consisting of channels parallel to the central axis of the wheel and exchanges heat and / or moisture with the adsorbent on the media. This media may comprise a substrate with a coating containing the adsorbent. The adsorbent may be a MOF, silica gel, zeolite, activated carbon, or another desiccant. The coating thickness may be between 10-500 microns. The pressure drop across the wheel may be less than or equal to 100 Pa. The ratio of open flow area to blocked flow area may be above 90%. In some embodiments, the adsorbent device is configured to be easily serviceable. An adsorbent wheel may be mounted on sliders, allowing it to slide laterally from its installed position to give better access to the wheel segments for servicing, cleaning, repair, or replacement.

[0089] In some embodiments, the adsorbent device is configured to be easily replaceable. An adsorbent wheel may be configured to mount on external rollers which center the wheel and allow it to rotate, and which may be movable or removable to allow the full wheel to be removed or replaced. In some embodiments, removability and / or replaceability of a portion and / or the total adsorbent device (e.g., a desiccant wheel) may advantageously allow the insertion of a fresh adsorbent (e.g., MOF) after some or all of the desiccant on the adsorbent device degrades. In some embodiments, removability and / or replaceability of the adsorbent device facilitates changing a desiccant present on the adsorbent device, e.g., depending on operating conditions, outdoor conditions, or the like.

[0090] Some aspects are related to methods. For instance, in some embodiments, the method is a method of conditioning air for a space to be conditioned. In some embodiments, the methods described herein utilize the systems described herein.

[0091] Methods include, in some embodiments, drawing air into a system. In some embodiments, the air may be ambient air, e.g., air obtained from an outdoor environment (outdoor air, OA). In some embodiments, the air may be return air (RA) from the space to be conditioned. In some embodiments, combinations of ambient air and return air may be used. In some embodiments, air from the space to be conditioned but is then exhausted is referred to as exhaust air (EA). Selection of the location from which air is drawn into the system may be determined based on outdoor conditions and / or the desired function of the air. For instance, if the air is to be conditioned, it may be desirable to at least partially utilize return air from the space to be conditioned to decrease an energy load required to bring the air to the desired conditions. In some embodiments, it may be desirable to use ambient air, for instance, if return air from the space to be conditioned is unavailable or undesirable to use. Some such cases may include a space where air may be at least partially contaminated with a contaminate that would be detrimental to the system for conditioning air. For example, in some instances, the space to be conditioned may process food, and thus oil may be present in the air. The use of return air from such a space may contaminate a system with the oil present from the return air. It will be understood that the source of air, whether ambient or return air, may be utilized for either a process air stream, a regeneration air stream, and / or an auxiliary air stream. In some embodiments, a first air source may be used at a first location in an air stream and a second air source may be used at a second location in the air stream, where the second location is downstream of the first location. For instance, exhaust air may be provided at a first inlet of a regeneration air stream upstream of an ERV, and then outdoor air may be provided at a second inlet of the regeneration air stream downstream of the ERV.

[0092] In some embodiments, e.g., those shown in FIGS. 5A-5F, outdoor air (OA) is provided to the process air stream 304. Alternatively, it is possible to use return air (RA) in place of the OA. Using RA may reduce an energy load of the system, e.g., if the RA is partially conditioned relative to OA. In some embodiments, e.g., again those shown in FIGS. 5A-5F, exhaust air (EA) is provided to the regeneration air stream 314. Alternatively, it is possible to use outdoor air (OA) in place of the EA. Using OA may facilitate regenerating the wheel when the OA has a low relative humidity, in accordance with some embodiments. Moreover, using OA, in some cases, may provide a higher air flow velocity over the desiccant wheel, which may also facilitate regenerating a desiccant thereon.

[0093] Drawing the air may be accomplished in any of a variety of suitable methods, according to some embodiments. In some instances, a blower may be used. Accordingly, air may be blown and / or pulled into the system using the blower. The air may be part of a process air stream, a regeneration air stream, and / or an auxiliary air stream, in some embodiments. Other air streams are also possible, in accordance with some embodiments. According, drawing air into the system may comprise forming a process air stream, forming a regeneration air stream, and / or an auxiliary air stream. It will be understood that air may be drawn into the system through one or more inlets of various conduits of the system (e.g., a conduit defining a process air stream, a conduit defining a regeneration air stream, a conduit defining an auxiliary airstream, etc.).

[0094] In accordance with some embodiments, the methods may include contacting air from a process stream with a cooling heat exchanger and then a process portion of an adsorbent device (e.g., desiccant wheel) to form supply air to the space to be conditioned. In some embodiments, the method includes contacting air from a process stream with an evaporator and then a process portion of a desiccant wheel to form supply air to the space to be conditioned. In accordance with some embodiments, the methods may include contacting air from a process stream with a cooling heat exchanger and then a process portion of a desiccant wheel to form supply air to the space to be conditioned. In some embodiments, contacting air from a process stream with a cooling heat exchanger may be used to cool the air to a desired temperature. In some embodiments, contacting air from a process stream with a cooling heat exchanger may cool the air to a temperature cooler than the desired temperature. For instance, in some embodiments, contacting air from a process stream with a cooling heat exchanger may cool the air until it is saturated with moisture, and then the cooling heat exchanger may further cool the air to at least partially dehumidify the air. In some embodiments, contacting air from a process stream with a cooling heat exchanger may include removing a substantial portion of moisture from the air, for instance, at least 5%, at least 10%, at least 20%, at least 30%, at least 40%, at least 50% and / or up to 60%, up to 70%, up to 80%, or up to 90% of the moisture from the air (e.g., lowering an absolute humidity of the air by a corresponding amount).

[0095] In some embodiments, the method includes contacting the air with a process portion of an adsorbent device (e.g., desiccant wheel). In some instances, contacting the air with a process portion of an adsorbent device dehumidifies the air and warms the air, e.g., due to a heat of adsorption. For this reason, in some embodiments, the air is cooled beyond a desired temperature by the cooling heat exchanger, as the temperature of the air is later raised by contacting the adsorbent device. In some instances, the air of the process stream is then provided to the space to be conditioned as supply air.

[0096] According to some embodiments, the method may further include contacting the air of the process stream with a second cooling heat exchanger. In some instances, the second cooling heat exchanger may be positioned upstream of the adsorbent device, such that the air of the process stream first contacts a first cooling heat exchanger, then a second cooling heat exchanger, and then the adsorbent device. In some embodiments, the second cooling heat exchanger may be positioned downstream of the adsorbent device, such that the air of the process stream first contacts a first cooling heat exchanger, then the adsorbent device, and then the second cooling heat exchanger. In this latter arrangement, the air may be further cooled to reach desired conditions before being provided to the space to be conditioned, for instance, if the heat of adsorption from the adsorbent device heated the air of the process stream beyond the desired temperature.

[0097] In the arrangement described where the process air stream contacts a cooling heat exchanger followed by the adsorbent device (e.g., see FIG. 1) before being provided to the space to be conditioned as supply air, the cooling heat exchanger (e.g., an evaporator) may be operated at a temperature above that of the dew point temperature of the supply air. Accordingly, in some embodiments, a dew point temperature of the supply air is less than or equal to a temperature of the cooling heat exchanger. In some embodiments, the cooling heat exchange (e.g., an evaporator) is operated at a temperature at least 1 degrees C, at least 2 degrees C, at least 3 degrees C, at least 4 degrees C, at least 5 degrees C, at least 6 degrees C, at least 8 degrees C, or at least 10 degrees C and / or no more than 12 degrees C, no more than 15 degrees C, or no more than 20 degrees C higher than a dew point temperature of the supply air. This may desirably increase efficiency of the systems and methods, compared to typical methods absent the adsorbent device, as energy to cool and dehumidify the air by the cooling heat exchanger is less efficient than separately conditioning the sensible and latent heat loads of the air before providing it to the space to conditioned are not needed.

[0098] The method, in some embodiments, comprises contacting air of the regeneration stream with a heating heat exchanger and a regeneration portion of the adsorbent device (e.g., desiccant wheel). In some embodiments, the method includes contacting air from the space to be conditioned with a condenser and then a regeneration portion of the adsorbent device (e.g., desiccant wheel). In some embodiments, the heating heat exchanger is operated to heat the air of the regeneration air stream such that it may at least partially regenerate the regeneration portion of the desiccant wheel. Regeneration, as described elsewhere herein, is generally related to removing moisture from the regeneration portion of the adsorbent device so that it may then be repositioned to the process portion of the system to condition air of the process stream. In some embodiments, for instance when the adsorbent device comprises a MOF (e.g., a desiccant wheel comprising a MOF), the heat needed to regenerate the regeneration portion of the adsorbent device is low due to certain isotherm parameters of the MOFs, as compared to adsorbent devices comprising typical desiccant materials such as silica gels or alumina. Accordingly, in some embodiments, a temperature of the heating heat exchanger (e.g., a condenser) is less than or equal to 60 degrees C, less than or equal to 55 degrees C, less than or equal to 50 degrees C, less than or equal to 45 degrees C, or less than or equal to 40 degrees C and / or greater than or equal to 35 degrees C or greater or equal to 30 degrees C.

[0099] In some embodiments, when the adsorbent device comprises or is a desiccant wheel, the method includes rotating the desiccant wheel such that a first section of the wheel functioning as the process portion and a second section of the wheel functioning as the regeneration portion switch positions in the system so that the second section if the wheel functions as the process portion and the first section of the wheel functions as the regeneration portion.

[0100] In some embodiments, the method includes flowing air from the process air stream or the regeneration air stream through a bypass conduit. In some embodiments, the method includes flowing at least some of the air (and up to all) of the process air stream through a bypass conduit (e.g., a first bypass conduit) such that it does not contact a process portion of the adsorbent device (e.g., desiccant wheel). In some embodiments, the method includes flowing at least some of the air (and up to all) of the regeneration air stream through a bypass conduit (e.g., a second bypass conduit) such that the air does not contact the heating heat exchanger and / or the regeneration portion of the adsorbent device. In some embodiments, the method includes flowing all of the air of a regeneration air stream through a bypass conduit such that the air does not contact the heating heat exchanger and / or the regeneration portion of the adsorbent device. In some embodiments, it may be desirable to flow air through a bypass conduit bypassing the process portion of the adsorbent device when no dehumidification or less dehumidification than is possible from the adsorbent device is needed. In some embodiments, it may be desirable to flow air through a bypass conduit bypassing the heating heat coil and / or the regeneration portion of the adsorbent device when it is desirable to increase or maintain a temperature of the heating heat coil and / or when a regeneration portion of the adsorbent device does not need to be fully generated (e.g., if the process portion is not being used or only partially being used). In some such embodiments, utilizing one or more bypass conduits may improve efficiency of air flow through the systems described herein by avoiding a pressure drop through an adsorbent device. In some embodiments, utilizing one or more bypass conduits may improve the lifetime of the adsorbent device, as it may avoid air passing therethrough when it is unneeded to condition air.

[0101] The methods described herein include, in accordance with some embodiments, contacting air from an auxiliary stream with a second heating heat exchanger. In some embodiments, the second heating heat exchange is on the same refrigerant circuit as a first heating heat exchanger (e.g., where the first heating heat exchanger is in fluidic communication with a regeneration portion of an adsorbent device). In some embodiments, the second heating heat exchanger is configured to remove at least a portion of the heat produced at the first and / or second cooling heat exchangers. In some embodiments, the second heating heat exchanger is configured to remove at least a portion of the heat produced at the first and / or second cooling heat exchangers. In accordance with some embodiments, the second heating heat exchanger removes at least the same amount, at least 2 times, or at least 3 times and / or up to 4 times or up to 5 times the amount of heat from the refrigeration circuit as the first heating heat exchanger.

[0102] In some embodiments, the method includes passing an auxiliary air stream through an auxiliary conduit, which is a separate conduit from the first conduit and second conduit which may be respectively associated with a process air stream and a regeneration air stream. In some embodiments, the method includes passing at least the same amount, at least 1.5 times, or at least 2 times and / or up to 2.5 times or up to 3 times the amount of air flow through the second heating heat exchanger as through the first heating heat exchanger. In some such embodiments, more heat is removed from the refrigeration circuit via the second heating heat exchanger due to the higher volumetric air flow therethrough, compared to that of the first heating heat exchanger.

[0103] In some embodiments, the method includes determining a humidity and / or a temperature of incoming and / or outgoing air from the system. In some instances, humidity and / or temperature sensors are used to determine the humidity and / or temperature. In some embodiments, an absolute humidity of the incoming and / or outgoing air from the system is determined. For example, in some embodiments, a method includes determining an absolute humidity of an incoming air stream. In some embodiments, the method includes determining an absolute humidity of a supply air stream. Determining the humidity and / or temperature of the air at one or more locations within the system may provide feedback for controlling the system, e.g., via one or more processors as described elsewhere herein.

[0104] In some embodiments, the systems described herein operate more efficiently than previous systems for conditioning air. For instance, in some embodiments , methods include operating a system having an integrated seasonal moisture removal efficiency of at least 4 Ibs / kWh, at least 5 Ibs / kWh, at least 6 Ibs / kWh, at least 7 Ibs / kWh, at least 8 Ibs / kWh, or at least 9 Ibs / kWh and / or no more than 10 Ibs / kWh, no more than 11 Ibs / kWh, no more than 12 Ibs / kWh, no more than 13 Ibs / kWh, or no more than 14 Ibs / kWh, according to AHRI920-2020 edition (ISMRE2). In some embodiments, the method comprises contacting air from a process stream with a cooler and a process portion of a desiccant wheel having a integrated seasonal moisture removal efficiency of at least 4 Ibs / kWh, at least 5 Ibs / kWh, at least 6 Ibs / kWh, at least 7 Ibs / kWh, at least 8 Ibs / kWh, or at least 9 Ibs / kWh and / or up to 10 Ibs / kWh, up to 11 Ibs / kWh, up to 12 Ibs / kWh, up to 13 Ibs / kWh, or up to 14 Ibs / kWh, according to AHRI920-2020 edition (ISMRE2), to form supply air to the space to be conditioned. In some such embodiments, the method further includes contacting air of the regeneration stream (e.g., from the space to be conditioned) with a heater and then a regeneration portion of the desiccant wheel.

[0105] The above methods may be implemented by one or more controllers including at least one processor operatively coupled to the various controllable portions of the systems as disclosed herein. The method may be embodied as computer readable instructions stored on non-transitory computer readable memory associated with the at least one processor such that when executed by the at least one processor the system may perform any of the actions related to the methods disclosed herein. Additionally, it should be understood that the disclosed order of the steps is exemplary and that the disclosed steps may be performed in a different order, simultaneously, and / or may include one or more additional intermediate steps not shown as the disclosure is not so limited. The following examples are intended to illustrate certain embodiments of the present invention, but do not exemplify the full scope of the invention.

[0106] EXAMPLE 1

[0107] This example describes the operation of an air conditioning system.

[0108] A system as shown in FIG. 1 was constructed and was operated to cool and dehumidify air for a space to be conditioned. FIG. 6 shows a plot of moisture removal efficiency (MRE) measured at the system over four days. The system operates at MRE values of at least 6 Ibs / kWh and up to 14 Ibs / kWh, demonstrating efficient operation.

[0109] While several embodiments of the present invention have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and / or structures for performing the functions and / or obtaining the results and / or one or more of the advantages described herein, and each of such variations and / or modifications is deemed to be within the scope of the present invention. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and / or configurations will depend upon the specific application or applications for which the teachings of the present invention is / are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of any appended claims and equivalents thereto, the invention may be practiced otherwise than as specifically described and claimed. The present invention is directed to each individual feature, system, article, material, and / or method described herein. In addition, any combination of two or more such features, systems, articles, materials, and / or methods, if such features, systems, articles, materials, and / or methods are not mutually inconsistent, is included within the scope of the present invention.

[0110] The indefinite articles “a” and “an,” as used herein in the specification and in any claims, unless clearly indicated to the contrary, should be understood to mean “at least one.” The phrase “and / or,” as used herein in the specification and in any claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Other elements may optionally be present other than the elements specifically identified by the “and / or” clause, whether related or unrelated to those elements specifically identified unless clearly indicated to the contrary. Thus, as a non-limiting example, a reference to “A and / or B,” when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A without B (optionally including elements other than B); in another embodiment, to B without A (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

[0111] As used herein in the specification and in any claims, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when separating items in a list, “or” or “and / or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of’ or “exactly one of,” or, when used in any claims, “consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e. “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of.” “Consisting essentially of,” when used in any claims, shall have its ordinary meaning as used in the field of patent law.

[0112] As used herein in the specification and in any claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and / or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

[0113] As used herein, “wt%” is an abbreviation of weight percentage. As used herein, “at%” is an abbreviation of atomic percentage.

[0114] Some embodiments may be embodied as a method, of which various examples have been described. The acts performed as part of the methods may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include different (e.g., more or less) acts than those that are described, and / or that may involve performing some acts simultaneously, even though the acts are shown as being performed sequentially in the embodiments specifically described above.

[0115] Use of ordinal terms such as “first,” “second,” “third,” etc., in any claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements.

[0116] In this document, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of’ and “consisting essentially of’ shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03

Claims

CLAIMSWhat is claimed is:

1. A method of conditioning air for a space to be conditioned, comprising: contacting air from a process stream with a cooling heat exchanger and then a process portion of a desiccant wheel to form supply air to the space to be conditioned; contacting air from the space to be conditioned with a first heating heat exchanger and a regeneration portion of the desiccant wheel; and contacting air from an auxiliary stream with a second heating heat exchanger, wherein: a dew point temperature of the supply air is less than or equal to a temperature of the cooling heat exchanger, and a temperature of the first heating heat exchanger is less than or equal to 60 degrees C.

2. A method, comprising: contacting air from a process stream with an evaporator and then a process portion of a desiccant wheel to form supply air to be delivered to a space to be conditioned; and contacting air from the space to be conditioned with a condenser and then a regeneration portion of the desiccant wheel, wherein: a dew point temperature of the supply air is less than or equal to a temperature of the evaporator, and a temperature of the condenser is less than or equal to 60 degrees C.

3. A method of conditioning air for a space to be conditioned, comprising: contacting air from a process stream with a cooling heat exchanger and a process portion of a desiccant wheel having an integrated seasonal moisture removal efficiency of at least 8 Ibs / kWh according to AHRI920-2020 edition (ISMRE2) to form supply air to the space to be conditioned; andcontacting air from the space to be conditioned with a heating heat exchanger and a regeneration portion of the desiccant wheel.

4. A method of conditioning air for a space to be conditioned, comprising: flowing air through a process air stream such that at least a portion of the air contacts a cooling heat exchanger and then a process portion of a desiccant wheel to form supply air to the space to be conditioned; flowing air through a regeneration air stream such that at least a portion of the air contacts a heating heat exchanger and then a regeneration portion of the desiccant wheel; and flowing at least a portion of the air of the regeneration air stream through a bypass conduit such that the air does not contact the heating heat exchanger or the regeneration portion of the desiccant wheel, wherein: a dew point temperature of the supply air is less than or equal to a temperature of the cooling heat exchanger, and a temperature of the heating heat exchanger is less than or equal to 60 degrees C.

5. A system for conditioning air, comprising: a first conduit defining a process air pathway and a second conduit defining a regeneration air pathway; a refrigeration circuit comprising a condenser and an evaporator; and a desiccant wheel having a process portion and a regeneration portion, wherein: a process air stream flowing through the process air pathway enters the first conduit, directly contacts at least a portion of the evaporator, and then contacts the process portion of the desiccant wheel, and a regeneration air stream flowing through the regeneration air pathway enters the second conduit, directly contacts at least a portion of the condenser, and then contacts the regeneration portion of the desiccant wheel.

6. A system for conditioning air, comprising: a first conduit defining a process air pathway and a second conduit defining a regeneration air pathway; a refrigeration circuit comprising a heating heat exchanger and a cooling heat exchanger; and a desiccant wheel having a process portion and a regeneration portion, wherein the second conduit comprises a bypass segment bypassing the heating heat exchanger and / or the desiccant wheel.

7. A system for conditioning air, comprising: a first conduit defining a process air pathway and a second conduit defining a regeneration air pathway; a first refrigeration circuit comprising a first heating heat exchanger and a first cooling heat exchanger; a second refrigeration circuit comprising a second heating heat exchanger and a second cooling heat exchanger; and a desiccant wheel having a process portion and a regeneration portion, wherein: a process air stream flowing through the process air pathway enters the first conduit, contacts at least a portion of the first cooling heat exchanger, contacts the process portion of the desiccant wheel, and contacts at least a portion of the second cooling heat exchanger, and a regeneration air stream flowing through the regeneration air pathway enters the second conduit, contacts at least a portion of the first heating heat exchanger, contacts the regeneration portion of the desiccant wheel, and contacts at least a portion of the second heating heat exchanger.

8. A system for conditioning air, comprising: a process air pathway having a process airflow direction; a regeneration air pathway having a regeneration airflow direction; a condenser;an evaporator; and a desiccant wheel positionable with a portion in the process air pathway and a portion in the regeneration air pathway, wherein: the process air pathway, in the process airflow direction, first contacts at least a portion of the evaporator and then contacts a portion of the desiccant wheel, and the regeneration air pathway, in the regeneration airflow direction, first contacts at least a portion of the condenser, and then contacts a portion of the desiccant wheel.

9. The method of claim 3 or the system of claims 5-8, wherein a dew point temperature of the supply air is less than or equal to a temperature of the cooling heat exchanger and / or wherein a temperature of the heating heat exchanger is less than or equal to 60 degrees C.

10. The method or system of any one of the preceding claims, wherein the desiccant wheel comprises a metal organic framework.

11. The method or system of claim 10, wherein the metal organic framework is coated on at least a portion of the desiccant wheel.

12. The method of claim 1, wherein the cooling heat exchanger, the first heating heat exchanger, and the second heating heat exchanger are positioned in series on a refrigeration circuit.

13. The method or system of any one of the preceding claims, wherein the system has an integrated seasonal moisture removal efficiency of at least 8 Ibs / kWh according to AHRI920-2020 edition (ISMRE2).

14. The method or system of any one of the preceding claims, wherein the heating heat exchanger comprises a condenser.

15. The method or system of any one of the preceding claims, wherein the cooling heat exchanger comprises an evaporator.

16. The method of any one of the preceding claims, further comprising flowing at least a portion of the air of the regeneration air stream through a bypass conduit such that the air does not contact the heating heat exchanger or the regeneration portion of the desiccant wheel.

17. The system of any one of the preceding claims, wherein the first conduit further comprises a bypass segment bypassing the cooling heat exchanger and / or the desiccant wheel.

18. The system of any one of the preceding claims, wherein the second conduit further comprises a bypass segment bypassing the heating heat exchanger and / or the desiccant wheel.

19. The method of any one of the preceding claims, further comprising determining an absolute humidity of an incoming air stream.

20. The method of any one of the preceding claims, further comprising determining an absolute humidity of a supply air stream.

21. The method or system of any one of the preceding claims, wherein the second heating heat exchanger removes up to 5 times the amount of heat from the refrigeration circuit as the first heating heat exchanger.

22. The method or system of any one of the preceding claims, wherein an air flow through the second heating heat exchanger is greater than or equal to the air flow through the cooling heat exchanger.

23. The method or system of any one of the preceding claims, wherein an air flow through the second heating heat exchanger is up to 3 times greater than the air flow through the first heating heat exchanger.

24. The method or system of any one of the preceding claims, wherein the system has an integrated seasonal moisture removal efficiency of no more than 14 Ibs / kWh according to AHRI920-2020 edition (ISMRE2).

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