DOUBLE HYBRID HEAT PUMP AND SYSTEM AND METHODS OF USE AND OPERATION

Abstract

A double hybrid heat pump, system, and method of operation that provides improved efficiency in both heating and cooling modes, hot water, and other benefits. The system includes a compressor for compressing a low pressure vapor refrigerant to a high pressure vapor refrigerant, and a refrigerant condensing heat exchanger that heats water and cools the refrigerant to a high pressure liquid refrigerant, which is fed to a refrigerant cooling heat exchanger where the remaining high pressure vapor refrigerant is condensed and the high pressure liquid refrigerant is further cooled. The high pressure cooled liquid refrigerant passes through an expansion valve to reduce the pressure of the cooled liquid to produce a low pressure cooled liquid refrigerant or a low pressure cooled two-phase refrigerant. The low pressure cooled liquid refrigerant or two-phase refrigerant is then evaporated in a refrigerant evaporation heat exchanger to produce a low pressure vapor refrigerant and returned to the compressor.

Description

[Technical field]

[0001] STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT: Not Applicable [CROSS REFERENCE TO RELATED APPLICATIONS] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63,183,615, filed May 3, 2021, the entire contents of which are incorporated by reference.

[0002] The present invention relates generally to heat pumps, and more particularly to hybrid heat pumps that can be used in combination with hot water and forced air systems for heating and domestic water supply, as well as cooling systems. [Background technology]

[0003] There is a growing market for residential, commercial, and industrial heat pump systems worldwide because they can be highly efficient and can be used to replace less efficient heating and cooling systems. Heat pumps have been introduced primarily into new or existing homes with forced air heating systems. Currently, retrofitting a home to a hot water heating system is prohibitively expensive for the average homeowner. Retrofitting these homes is limited to a few expensive options, including, for example: 1. Replacing all radiators or baseboards with larger radiators or panel radiators or baseboards capable of operating at lower heating supply temperatures (between 110 and 120 degrees); 2. Replacing hot water systems with forced hot air systems; 3. Using two heat pumps to provide hot air and water at the same time, or 4. Adding several hydronic air handlers and ducts to supplement the heat output from the existing heating system.

[0004] The cost of these options ranges from $70,000 to $100,000, which is prohibitively expensive for the average homeowner. Furthermore, the level of complexity of these retrofits can make these tasks undesirable for installers. The penetration of heat pump systems in commercial and industrial markets has lagged compared to the residential market, at least in part due to the additional complexities and requirements of these systems, such as the need for chilled water. Thus, there remains a need for lower cost, higher performance heat pumps, systems, and methods that can be used for new installations and retrofit applications for both existing forced air and forced water heating systems for residential, commercial, and industrial buildings. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] (See International Search Report) Summary of the Invention

[0006] SUMMARY OF THE PRESENT EMBODIMENT The present invention addresses the above needs by providing a dual hybrid heat pump that can be used in new installations and retrofit applications for buildings having forced air or hot water heating systems.

[0007] A double hybrid heat pump includes a compressor that compresses low pressure gas phase refrigerant to high pressure gas phase refrigerant, and a refrigerant-water condensing heat exchanger that uses heat from the high pressure refrigerant to generate and store hot water. The condensed refrigerant is then sent to a refrigerant cooling heat exchanger where it exchanges heat with a cooler fluid than the condensing heat exchanger to further cool the high pressure liquid refrigerant. The high pressure cooled liquid refrigerant passes through an expansion valve to reduce the pressure of the cooled liquid. The low pressure cooled liquid refrigerant or liquid / gas two-phase mixture refrigerant is then fed to a refrigerant evaporation heat exchanger to evaporate the low pressure refrigerant before it is returned to the compressor.

[0008] In various embodiments, the water heated by the condensing heat exchanger is supplied to one or both of: 1) a hot water tank for use as hot water for storage or domestic hot water; and 2) a hot water circulation heating loop that can serve various applications. For example, in a hot water heating system with a boiler, in heating mode, the double hybrid heat pump can make hot water for use as either domestic hot water or hot water circulation hot water instead of the heating boiler, and can also provide hot air from inside the refrigerant-air heat exchanger for heating. Meanwhile, in cooling mode, the double hybrid heat pump can provide hot water for domestic hot water and cold air for air conditioning. While in cooling mode, the first condenser first absorbs the heat rejected by the compressor, and the remaining heat is rejected outside the system. In cooling mode, if conditions permit, the system prioritizes condensation to generate useful hot water, and then can use the favorable temperature difference to further subcool the refrigerant before it reaches the thermal expansion valve, greatly increasing the net efficiency of the system.

[0009] A double hybrid heat pump can be used to eliminate many external components, complex controls, and the extensive labor required to retrofit a home from an existing hot water heating system to a ground source or water source heat pump. A double hybrid heat pump can be installed with minimal training and has built-in features that limit risk to the installer. For example, in a hot water heating system, the present invention can be used to eliminate the domestic hot water preheat tank, one heat pump, one flow center, one HDPE manifold, one circulator, domestic hot water piping, hot water circulation fan coil, and extra zone controls, resulting in substantial installation and operational savings.

[0010] Thus, the present disclosure addresses the continuing need for HVAC systems with improved cost and performance.

[0011] The accompanying drawings are included for purposes of illustrative illustration of various aspects of the invention and not for purposes of limiting the invention. [Brief description of the drawings]

[0012] [Figure 1A] 1 shows an exemplary schematic embodiment of a double hybrid heat pump. [Figure 1B] 1 shows an exemplary schematic embodiment of a double hybrid heat pump. [Figure 2A] 1 shows an exemplary schematic embodiment of a double hybrid heat pump. [Figure 2B] 1 shows an exemplary schematic embodiment of a double hybrid heat pump.

[0013] [Figure 3A] 3A and 3B show pressure versus enthalpy for exemplary refrigeration heating and cooling cycles of the prior art and the present invention, respectively. [Figure 3B] 3A and 3B show pressure versus enthalpy for exemplary refrigeration heating and cooling cycles of the prior art and the present invention, respectively.

[0014] [Figure 4A] An exemplary embodiment of a DHHP is shown with separate refrigerant and water portions for ease of viewing. [Figure 4B] An exemplary embodiment of a DHHP is shown with separate refrigerant and water portions for ease of viewing. [Figure 4C] An exemplary embodiment of a DHHP is shown with separate refrigerant and water portions for ease of viewing. [Figure 4D] An exemplary embodiment of a DHHP is shown with separate refrigerant and water portions for ease of viewing.

[0015] [Diagram 5] 1 illustrates an exemplary geothermal retrofit using prior art systems and methods.

[0016] [Figure 6] 1 illustrates an exemplary geothermal retrofit using the present invention.

[0017] [Figure 7A] 1 illustrates an exemplary geothermal retrofit using the prior art systems and methods of the present invention; [Figure 7B] 1 illustrates an exemplary geothermal retrofit using the prior art systems and methods of the present invention; [Figure 7C] 1 illustrates an exemplary geothermal retrofit using the prior art systems and methods of the present invention;

[0018] [Figure 8] 1 illustrates an exemplary commercial air handler.

[0019] [Figure 9] 1 illustrates an exemplary embodiment of how a double hybrid heat pump is retrofitted into an exemplary commercial air handler.

[0020] [Figure 10] 1 shows an exemplary embodiment of how a double hybrid heat pump can be constructed as a commercial air handling unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] In the drawings and detailed description, the same or similar reference numbers may identify the same or similar elements. It will be understood that implementations, features, etc. described with respect to an embodiment of a particular figure may also be implemented with respect to other embodiments of other figures, unless expressly stated or otherwise possible.

[0022] The system 100, the dual hybrid heat pump 50, and the methods of use, operation and control of the present invention may be used for a variety of heating and water solutions within the structure 200.

[0023] 1A-2B show an exemplary schematic embodiment of a double hybrid heat pump 50. The compressor 1 receives a low pressure gaseous refrigerant at the inlet and then compresses it to a high pressure gaseous refrigerant, which passes through the outlet and is supplied to the inlet to the refrigerant condensing heat exchanger 3 via connection 2. The refrigerant passes through the condensing heat exchanger 3 and is cooled by a first cooling fluid, which may be water or another fluid that may be used elsewhere depending on the application. In various embodiments, the first cooling fluid may be circulated using a water tank circulation pump 35 from a tank 36 through the condensing heat exchanger 3 via connections from 33, 34, 37, and 38 to remove heat from the high pressure gaseous refrigerant. It will be understood that the high pressure gaseous refrigerant may be fully or partially condensed to a liquid at the outlet to the condensing heat exchanger 3. If the refrigerant is partially condensed, a two-phase refrigerant mixture leaves the refrigerant condensing heat exchanger 3 and is fully condensed and subcooled in the cooling heat exchanger as described herein.

[0024] The condensed refrigerant is fed from the outlet of the condensing heat exchanger 3 through connection 4 to a reversing element 15 via port 5 which serves as an inlet. Those skilled in the art will appreciate that the word "port" as used herein may describe an access point to hardware and / or software. For example, a port may serve as an inlet or entry point to a device, or an outlet or exit point from a device, depending on the direction of fluid flow, current flow, etc. Similarly, a connection may be a direct or indirect physical or logical connection between hardware and / or software.

[0025] 1A and 2A, the reversing element 15 is configured to send the condensed refrigerant through connection 7 and through port 10, which serves as an inlet, to a refrigerant-to-second fluid heat exchanger 11, which functions as a refrigerant cooling heat exchanger and further cools the fully or partially condensed liquid using a second cooling fluid, e.g., air, to remove heat from the refrigerant. The second cooling fluid may be used for other purposes, such as providing hot air for heating the structure 200 or being exhausted.

[0026] Those skilled in the art will appreciate that by maintaining the temperature of the second cooling fluid, e.g., air, lower than the temperature of the first cooling fluid, e.g., water, the refrigerant can be subcooled more than is achievable with the first cooling fluid alone, resulting in greater efficiency from system 50 as compared to the prior art.

[0027] The heat exchanger 11 is typically located inside the structure 200. In various embodiments, the compressor 1, the condensing heat exchanger-sump tank 36, and the heat exchanger 11 may be housed in the same physical unit or in multiple units that may be located in close proximity for ease of installation and maintenance. It will be further understood that the heat exchangers and other devices used in the present invention may include one or more stages that may be operated as a single unit or separately by one of ordinary skill in the art.

[0028] In various embodiments using air as the second fluid, one or more blowers 12 may be provided in close proximity to the heat exchanger 11 that may be controlled to control the amount of heat transferred within the heat exchanger 11. The blowers 12 may be connected to ducts within the structure 200 to allow hot and cold air to be distributed within the structure 200 in heating and cooling modes, respectively. Using various control algorithms, the amount of heat extracted by the blowers 12 may be controlled for human comfort by balancing the air flow rate, the temperature of the refrigerant, and secondary effects caused by further cooling of the refrigerant. By subcooling the condensed liquid entering the heat exchanger 11 via port 10 using the relatively low temperature of the return air, more heat may be extracted from the refrigerant, increasing overall efficiency. Thus, a cooler refrigerant may absorb more heat in the heat exchanger 27 per pound of refrigerant passing through the system.

[0029] In the heating mode as shown in FIGS. 1A and 2A, the high pressure cooled refrigerant leaves the cooling heat exchanger 11 through port 13 which serves as an outlet and is fed to the expansion valve 17. A reversible filter dryer 14 may be disposed between the refrigerant-air heat exchanger and the expansion valve 17, or may be disposed elsewhere in the system 50 to remove debris from the refrigerant. The expansion valve 17 applies a pressure drop to the high pressure cooled refrigerant and outputs a low pressure cooled liquid or two-phase mixed refrigerant as required. The expansion valve 17 may be connected to a storage tank to store the refrigerant if the amount of refrigerant required in the heating and cooling modes differs in one embodiment of the system 50. Although the term expansion valve 17 is used herein, it will be understood that the term expansion valve can include other types of expansions designed to induce a pressure drop in the system 50.

[0030] In the embodiment of Figure 1A, refrigerant exits the storage tank through port 20 and enters reversing element 23 at port 21. In the heating mode, the refrigerant is directed by reversing element 23 to exit port 24 and travels to refrigerant-to-source heat exchanger 27, which functions as an evaporative heat exchanger for the refrigerant in the heating mode.

[0031] Heat exchanger 27 may be located outside of structure 200. Heat exchanger 27 may be embodied in a variety of heat exchanger designs using a variety of heat exchange media including gas, solid, or liquid, as known in the art. For example, heat exchanger 27 may be a geothermal heat exchanger in which heat is exchanged between solid soil and / or water in a well, or a refrigerant-to-air heat exchanger.

[0032] Low pressure evaporated refrigerant enters and leaves heat exchanger 27 via connections 26 and 25, respectively, and travels to reversing element 23. In heating mode, low pressure evaporated refrigerant enters and leaves reversing element 23 via ports 22 and 28, respectively. As is known in the art, some reversing elements 23, e.g., valves, have smaller inlets than outlets, and a suitable reversing element must be selected to allow for a low pressure drop across port 28. For example, a 3 ton compressor using a 7 / 8 inch suction port to the compressor may be best served by a reversing element having at least a 5 / 8 inch inlet to port 28, although a larger reversing element with a 7 / 8 inch inlet may be used to further reduce pressure and increase efficiency.

[0033] The low pressure evaporated refrigerant exits port 28 and travels to port 8 of reversing element 15. In the heating mode, the low pressure evaporated refrigerant exits reversing element 15 via port 9 and is returned to compressor 1 via connection 29 to complete and repeat the cycle.

[0034] 1A and 1B embodiment allows the heat exchanger 27 to be operated in either a counter-flow or parallel-flow configuration for both heating and cooling. As known to those skilled in the art, the flow configuration can significantly change the performance of the system 50 when the heat exchanger 27 is configured to use a heating exchange fluid pumped through the heat exchanger 27 via ports 32 and 31 by the pump 30. It will also be appreciated that the flow direction does not affect the efficiency of the heat exchanger 27 when the refrigerant heat exchanger 27 is a source / sink heat exchanger, i.e., when the heat exchange medium is a plenum (soil, bulk air, water or other fluid) that can be treated as a constant temperature on the time scale of the heat exchanger.

[0035] In the cooling mode, as shown in Figures 1B and 2B, reversing element 15 is set to route high pressure liquid refrigerant from condensing heat exchanger 3 to refrigerant-to-source heat exchanger 27 via connection 5 to port 8, and in the embodiment of Figures 1A and 1B, via reversing element 23 to port 28. Reversing element 23 is also shifted to route high pressure refrigerant to heat exchanger 27 through port 24. In the cooling mode, refrigerant-to-source heat exchanger 27 functions as a refrigerant cooling heat exchanger that further cools the liquid refrigerant and outputs the cooled liquid refrigerant via connection 25.

[0036] As in the heating mode, a control algorithm is typically used to regulate the amount of heat extraction from the heat exchanger 27. If the heat exchanger 27 has a lower temperature than the heat exchanger 3, it is possible to sub-cool the refrigerant entering the expansion valve 17 to a significant extent, thus improving the cooling capacity of the evaporative heat exchanger 11 compared to using only the heat exchanger 3. More generally, the overall efficiency of the system 100 can be improved if a refrigerant cooling heat exchanger is used to exchange heat with a heat exchange medium that is colder than water that exchanges heat with the refrigerant in the refrigerant condensing heat exchanger.

[0037] In the cooling mode, by appropriately adjusting the speed of the pump 30 to the source / sink heat exchanger, the system 50 can condense the high pressure refrigerant in heat exchanger 3 and then further subcool this liquid in heat exchanger 27. The amount of subcooling depends on the relative temperatures of the interacting fluids on heat exchangers 3 and 27, as well as the size and design of the heat exchangers. Fully condensed and subcooled refrigerant can extract more heat from heat exchanger 11, improving the efficiency of the cooling mode.

[0038] 1B embodiment, the refrigerant returns through reversing element 23 via port 22 and port 21. Excess refrigerant, if any, is collected in storage tank 19 at port 20 and can re-enter the circulation loop via port 18. The circulating high pressure sub-cooled liquid refrigerant passes through expansion valve 17, which imparts a pressure drop to the refrigerant resulting in a low pressure cooled liquid refrigerant.

[0039] Low pressure chilled liquid refrigerant is fed through port 13 to heat exchanger 11, which functions as an evaporative heat exchanger. The refrigerant partially or completely evaporates within heat exchanger 11 and exits through port 10. In various embodiments, blower 12 circulates the cool air from heat exchanger 11 throughout structure 200 via ducts. However, other heat exchange media may be used in heat exchanger 11 depending on various factors such as the desired efficiency and / or use of the energy transferred from the refrigerant.

[0040] In cooling mode, low pressure evaporated refrigerant leaving heat exchanger 11 via port 9 is returned to compressor 1 through reversing element 15 via ports 7 and 9 to complete and repeat the cycle.

[0041] The embodiment of Figures 1A-2B may be used in a heating mode to simultaneously provide both hot water for use as heating and domestic hot water and hot air for heating, and in a cooling mode to simultaneously provide both hot water and cold air for use as domestic hot water. In applications such as buildings with dehumidification that require simultaneous heating and cooling, cold air can be generated from chilled water from a source loop simultaneously with hot water and domestic hot water. Hot water for use in both modes may be provided via tank 36. Domestic hot water may be provided via ports 42 and 43 through a water-to-water heat exchanger 41, often referred to as an indirect heat exchanger, in tank 36.

[0042] It will be appreciated that hot water production may be effectively bypassed or reduced and the heat pump system 50 may be used only to provide hot or cold air by reducing the flow from the circulator 35 to the heat exchanger 3. In this mode, the heat exchanger 11 functions as a condensing heat exchanger in the heating mode and as an evaporating heat exchanger in the cooling mode. Conversely, the heat exchanger 27 functions as an evaporating heat exchanger in the heating mode and as a condensing heat exchanger in the cooling mode.

[0043] Similarly, forced hot or cold air distribution to structure 200 may be reduced, stopped, or bypassed when only hot water production is desired. In various embodiments, blower 12 may be slowed down or not operated in the configurations of Figures 1A-2B, thereby reducing heat transfer in heat exchanger 11 and air flow through the ducts. Alternatively, heat exchanger 11 may be bypassed using a bypass valve (not shown).

[0044] The embodiment of Figures 1A-2B includes several elements that make the double hybrid heat pump more efficient and easier to install than prior art units. For example, heat introduced by compressor 1 can be extracted via condensing heat exchanger 3, which may have a pump installed in close proximity to heat exchanger 3 or tank 36. Heat exchanger 3 can be sized to achieve various operating scenarios. For example, in various embodiments, heat exchanger 3 can be sized to transfer heat from the refrigerant until it is 100% liquid at a pressure and temperature very close to the temperature of the incoming fluid, since heat transfer performance tends to change over the life of the heat exchanger. For example, heat exchanger 3 may be designed to have small approach temperatures such that the temperature of the water exiting the heat exchanger at port 34 and the temperature of the refrigerant entering heat exchanger 3 at port 2 are within a few degrees, e.g., 3 degrees, of each other under full load conditions.

[0045] Additionally, the blower speed, and therefore the amount of heat transferred in the refrigerant-to-air heat exchanger 11, can be adjusted based on a feedback loop to target a particular final refrigerant temperature. Because much of the heat from the refrigerant has already been removed by the condensing heat exchanger 3, the blower 12 can operate at a slower speed to avoid blowing large amounts of air into the building that may be uncomfortable for the occupants. The blower 12 may be set to cool the refrigerant to a predetermined temperature higher than the inlet air temperature. For example, if the inlet air temperature is 60 degrees, the refrigerant saturation temperature is 120 degrees, and the predetermined set point is 15 degrees higher than the inlet air temperature, the blower 12 will adjust to set the outlet refrigerant temperature at port 13 to 75 (60+15) degrees, resulting in a subcooling of 45 degrees from the discharge saturation temperature.

[0046] The effect of using the subcooling heat exchanger (heat exchanger 11 for heating and heat exchanger 27 for cooling) is significant. The additional subcooling improves the overall efficiency of the refrigeration cycle by putting a greater load on the evaporator. Furthermore, because the subcooling is performed by the subcooling heat exchanger, the pressure and temperature of the refrigerant entering the condensing heat exchanger can be lowered, reducing the work done by the compressor.

[0047] A similar effect occurs in the evaporator: when high pressure refrigerant is subcooled by colder fluid in the refrigerant cooling heat exchanger, the refrigerant passes through the expansion device with less residual heat. As a result, the expansion device is less restricted, allowing the refrigerant pressure to increase, increasing efficiency and reducing compressor power input.

[0048] Performance data collected from experimental testing indicates that an additional 30 degrees of subcooling improves heat extraction by the evaporative heat exchanger 27 by 21-30%. In addition, this performance improvement also reduced compressor power consumption by 3%.

[0049] The inclusion of the water storage tank 36 can provide several advantages over prior art systems, depending on the deployment scenario. For example, a dual hybrid heat pump system 50 including the tank 36: 1. It can eliminate the need for installers to size and purchase a separate buffer tank, thus reducing the cost and complexity of the project. 2. Heat pumps can operate at different flow rates between the hot water condenser and the building load pump. Manufacturer recommended minimum flow rates for prior art heat pumps that do not use variable speed compressors are typically in the range of 3 gallons per minute. This flow rate can be difficult for many buildings, as a 5 ton system requires a minimum of 15 gallons per minute to flow through the system. This flow rate is too high for homes with existing boilers used at low flow rates and high temperature differentials. As a result, larger pumps are used to meet the minimum flow rate, but the water is split between the structure 200 and a buffer tank. 3. Compressor load fluctuations can be mitigated without the use of variable frequency drive (VFD) components, which add significant cost and complexity. 4. Heat storage can be done within the system, for example a 50 gallon tank can be used to store approximately 25,000 BTUs of heat. 6. It is possible to allow seamless integration between the hot water electric backup heat and the heat pump via the resistive element 45. This reduces the risk that an error by the installer will lead to under-utilization of the heat pump. 7. Allows an indirect hot water heat exchanger to be used for domestic hot water preheating when the tank is filled with hot water circulating water. In this example, a second advantage is that a double-walled heat exchanger is not required since there are two media between the refrigerant and the domestic water. 8. It allows the capture of a large part of the heat that would otherwise be wasted during heating and cooling operation. In cooling mode, this heat can be utilized for domestic hot water, such as by the indirect heat exchanger 41. When the heat pump is operating in cooling mode, the structure 200 can benefit from this hot water by recovering the "free hot water", i.e. the hot water as a by-product of cooling, in the water tank 36, unlike conventional air conditioning systems that reject heat to the outside by the condenser unit. Also, compared to most geothermal systems that use a desuperheater for domestic hot water, this system is able to recover more than 90% of the heat that would normally be rejected in the case of overheating only (usually less than 15% of the total). In both heating and cooling modes, the heat added by the compressor 1 is first sent to this tank and can be used as needed with limited additional mechanical equipment (no additional mechanical equipment is required to supply domestic hot water). 9. Allows the heat pump controller to sense building loads by temperature changes without the rapid fluctuations in refrigerant pressure caused by directly piping the hot water return to the heat pump.

[0050] 2A and 2B, as previously discussed, show a double hybrid refrigeration cycle with only a single reversing element 15. The disadvantage of a single reversing element 15 is that in one mode of operation, usually the cooling mode, the refrigerant, if used, must be in co-current with the source / sink loop. However, this configuration would still be preferred over other prior art techniques since it still allows for subcooling of the refrigerant in both the heating and cooling modes.

[0051] As previously mentioned, the double hybrid system 50 has several advantages for retrofitting residential structures with existing hydronic heating infrastructure. These buildings may have hydronic heating elements, typically baseboards, radiators, or radiant floors, that were sized at installation based on higher temperature, i.e., 160-180 degrees hot water, the typical supply temperature of a conventional boiler. These same heating elements only need to have a fraction of their original capacity when connected to a water supply that is at a temperature typical of a heat pump system (110-120 degrees).

[0052] The double hybrid heat pump 50 can be configured to simultaneously generate hot water for a hydronic system and hot air for heating from the same unit to overcome the heat deficit caused by using cooler water in the hydronic system. As mentioned above, generating the two simultaneously greatly improves efficiency and allows the hot air to be used to supplement the heating elements in retrofitted buildings.

[0053] Additionally, the double hybrid system 50 has an additional advantage in terms of overall system efficiency compared to a prior art hot water only heat pump. For example, a building that may be heated on peak days with 120 degree hot water would require a hot water only heat pump to provide the 120 degree hot water, but the double hybrid system 50 can operate at a lower hot water temperature, e.g., 100 or 110 degrees, and then simultaneously provide heated forced air to provide the same overall heating effect to the building. Those skilled in the art will appreciate that even a few degrees lower in supply temperature can make a big difference in heat pump efficiency. For example, a 10 degree decrease in supply temperature can increase the coefficient of performance by 25%.

[0054] Additionally, if the building's heating element is severely limited, the unit can alternate between producing hot air only and both hot air and hot water so that the unit's heat production is not limited by the capacity of the heating element in the building.

[0055] Those skilled in the art can use other devices in system 50. For example, a desuperheater can be used between compressor 1 and condensing heat exchanger 3 to pre-cool the high pressure, high temperature steam before it enters condensing heat exchanger 3.

[0056] 3A and 3B show pressure vs. enthalpy for exemplary refrigeration heating and cooling cycles of the prior art and the present invention. The solid black line is a standard prior art water-water heat pump system, and the dashed purple line shows a refrigeration cycle with subcooling and condensing heat exchangers. The larger width of the refrigeration cycle in FIG. 3A and 3B is due to the subcooling heat exchanger (HE) providing additional heat transfer from the refrigerant after it leaves the condensing heat exchanger 3. This results in a refrigeration cycle with greater refrigeration effect with less compressor work, resulting in higher efficiency. Those skilled in the art will appreciate that the refrigerant leaving the condensing heat exchanger 3 to be sent to the cooling heat exchanger, and the refrigerant leaving the expansion valve 17, can be 100% liquid or a two-phase mixture as desired. In the exemplary cycle 3B, the condensing heat exchanger 3 absorbs latent heat from the high pressure fluid, and then the subcooling heat exchanger 27 further cools the refrigerant to within a few degrees of the ground loop temperature.

[0057] Figures 4A-4D show an exemplary embodiment of a DHHP 50 with the refrigerant and water portions separated for ease of viewing. Figures 4A-4B and 4C-4D show the refrigerant and water portions, respectively, of an embodiment similar to that of Figures 1A and 2A in a heating mode configuration with a different placement of the circulation pumps 35 and 39.

[0058] While the use of two circulation pumps is not required, their inclusion in the packaged product provides several advantages, including: 1. Installation is faster and easier for installers, reducing on-site plumbing and simplifying wiring. 2. The heat pump supplies water to the hot water supply for the building's hot water circulation. 3. Supply pressure and flow rate are easier to adjust and therefore easier to fit into most homes. 4. By controlling the variable speed circulator through the DHHP, control integration can be further simplified for the installer, minimizing integration issues with existing systems. 5. The circulator can be turned off when necessary, for example when auxiliary heat is turned on, to allow a greater proportion of the heat to be expelled by the forced hot air.

[0059] The present invention reduces installation time and costs by reducing the need for extensive ducting, complex controls, hydronic air handlers, buffer tanks, additional circulators, or any other external equipment to operate.

[0060] Figures 5 and 6 provide a comparison of buildings that were evaluated for geothermal retrofit using prior art methods (Figure 5) and the present invention (Figure 6). The existing system may include a boiler and domestic hot water tank.

[0061] Using prior art methods, the refurbishment 1. A water-to-water heat pump for supplying hot water for heating and hot water for domestic use; 2. A water-to-air heat pump to provide hot and cold air for forced air heating and cooling; 3. A water buffer tank; 4. Two heat pump flow controllers; 5. Two water circulation pumps and associated piping for connection to the existing boiler and hot water tank; This may include the installation of.

[0062] A prior art installation such as that shown in FIG. 5 can cost in the range of approximately $70,000 to $100,000.

[0063] In contrast, the same retrofit using a double hybrid heat pump (FIG. 6) can be accomplished for approximately $50,000-$60,000 before incentives, since the design and associated costs are eliminated: one heat pump, a domestic hot water preheat tank, one circulation pump, and several fan coils and flow controllers. As will be further appreciated by those skilled in the art, a system 100 using a DHHP 50 will likely reduce maintenance and troubleshooting costs associated with the installed system.

[0064] FIG. 7A shows a typical prior art retrofit of a boiler-based heating system with a conventional heat pump. FIG. 7B and FIG. 7C show various embodiments of the system 100 with a DHHP 50 installed in a structure 200 in heating (7B) and cooling (7C) modes, respectively. FIG. 7B shows the heat flow within the structure 200 in heating mode and provides an exemplary use case. As previously described and as shown in FIG. 7B, the system 100 with a DHHP 50 supplies hot water to or in place of a boiler to support hot water heating and forced hot air for additional heating. Although FIG. 7B shows ducts and forced hot air serving only the first floor, one skilled in the art will understand that ducts can be provided to higher floors as desired to meet design and budgetary objectives.

[0065] 7C shows the flow of cool air within the structure 200 in cooling mode, and the supply of hot water for use as domestic hot water. These embodiments are particularly efficient because heat can be removed from the air within the structure 200 and used to heat water for use as domestic hot water.

[0066] While the present invention has been described in various embodiments as being used in conjunction with a boiler, unlike prior art units, the DHHP 50 of the present invention can be used to replace an existing boiler. The integration of refrigerant subcooling functionality can enable substantially higher coefficients of performance (COP), such as 3.5-4.5 in typical heating mode and up to 8-12 in cooling mode (accounting for hot water benefits), compared to COPs of 2.8-3.2 in heating mode and 4.5-6 in cooling mode, typical of water-to-water heat pumps with desuperheaters. Additionally, a system 100 using the DHHP system 50 of the present invention is easier to install, resulting in a lower risk of operator error and recalls for installers.

[0067] Those skilled in the art will appreciate that system 50 may be implemented with fixed or variable speed pumps and blowers 12 to provide flexibility of operation and control. For example, system 50 may use variable speed blower 12, which typically has a lower parasitic electrical load than multiple small single speed fans that may be used by hydronic air handlers, and more flexibility than a single fixed speed fan. Similarly, additional pumps 30 and 35 in system 50 may be variable speed.

[0068] FIG. 8 shows a typical air handling unit, which typically uses hot water from a boiler and cold water from a chiller to provide hot and cold air to a structure, respectively.

[0069] FIG. 9 shows how an air handler can be retrofitted with a commercially sized double hybrid heat pump system 50. There are several advantages to this approach. First, if the building has simultaneous heating and cooling loads, which is common in many commercial buildings, hospitals, factories, universities, and other situations, the DHHP system 50 can simultaneously generate hot water, hot air, and chilled water. For example, if the building needs heating, the double hybrid can generate hot water, e.g., 120 degrees, that can be used in the building for several uses, including heating the air handler heating coils. The refrigerant is then further subcooled by the incoming air handler air, which is assumed to be relatively cool, and the action of further cooling the refrigerant helps to preheat the air before it reaches the first air coil. The now subcooled refrigerant passes through an expansion valve and absorbs heat from the water supply. If the building needs chilled water, the return chilled water can be used for the refrigerant evaporator, or if chilled water is no longer needed, the geothermal heat exchange source method, the air heat exchange source method, or other heat exchange source methods such as geothermal borehole or dry coolers can be used.

[0070] One advantage of the DHHP system of the present invention is that it releases more heat by sub-cooling the refrigerant using an integral air coil as described in Figure 1A. In residential applications, the unit must be mindful of the exhaust temperature to avoid giving the homeowner a "cold draft" sensation. However, in commercial / industrial retrofit applications, this is less of a concern since the air is pre-heated entering the air handler as described in this example.

[0071] Furthermore, compared to prior art systems using modular water-to-water heat pumps, the double hybrid heat pump of the present invention can achieve significantly higher efficiency for two reasons: 1. The DHHP extends the refrigeration cycle by subcooling the refrigerant, resulting in more net heating and cooling while using less electricity. 2. During heating or cooling, the approach temperature of the refrigerant-air heat exchanger is favorable for transfer through two heat exchangers. For example, in cooling mode, the DHHP system 50 can receive 80 degree air and cool it with a refrigerant at about 50 degrees. However, the hot water circulation heat pump needs to produce 50 degree chilled water, which requires the refrigerant to be even cooler, perhaps 30-35 degrees. As is well known to those skilled in the art, a lower temperature refrigerant is less efficient because the compressor must work harder to compress the low pressure refrigerant to a higher pressure.

[0072] The DHHP system 50 can be designed in a modular manner to save space, reduce transportation challenges, and allow units to be combined on-site in a cascading manner to raise and lower for various building requirements.

[0073] For example, if a building requires air cooling, the DHHP system 50 can condense high pressure refrigerant to a liquid in a first heat exchanger to provide useful heat for a purpose such as domestic hot water, and then use a reversing element to send the refrigerant to a second heat exchanger, which is connected to a ground or air heat exchange source for further heat removal. If the temperature of the water entering the second heat exchanger was lower than the temperature of the water entering the first heat exchanger, the double hybrid can use the temperature difference to further subcool the refrigerant, releasing more heat from the refrigerant before expansion and evaporation. The subcooled refrigerant exits the second heat exchanger and enters the expansion device, becoming a low pressure, low temperature fluid. The DHHP system 50 can use the low pressure, low temperature fluid to pre-cool the incoming air before it reaches the first heating air coil.

[0074] FIG. 10 shows an example of a double hybrid heat pump integrated directly into a commercial or industrial air handler. This may be used in new buildings or to replace existing equipment. In this example, in multiple embodiments, the components used in FIGS. 1A-2B may be integrated into commercial or industrial units to provide high efficiency heating and cooling. They may be used in a modular arrangement or stand-alone configuration. In some cases, the system 50 may include hot or cold water storage.

[0075] The foregoing disclosure provides examples, illustrations, and descriptions of the present invention, but is not intended to be exhaustive or to limit the embodiments to the precise forms disclosed. Modifications and variations are possible in light of the above disclosure or may be acquired from practice of the implementations. These and other variations and modifications of the present invention are possible and contemplated, and it is intended that the foregoing specification and the following claims cover such modifications and variations.

[0076] As used herein, the term component is intended to be broadly interpreted as hardware, firmware, and / or a combination of hardware and software. It will be apparent that the systems and / or methods described herein may be implemented in different forms of hardware, firmware, or a combination of hardware and software. The actual dedicated control hardware or software code used to implement these systems and / or methods is not intended to limit the implementation. Thus, the operation and behavior of the systems and / or methods are described herein without reference to any specific software code, and it will be understood that software and hardware can be designed to implement the systems and / or methods based on the description herein.

[0077] Some implementations are described herein in relation to a threshold value. As used herein, meeting a threshold can refer to a value that is greater than the threshold, greater than the threshold, higher than the threshold, equal to or greater than the threshold, less than the threshold, less than the threshold, less than the threshold, less than the threshold, equal to or less than the threshold, etc.

[0078] Although particular combinations of features are recited in the claims and / or disclosed herein, these combinations are not intended to limit the disclosure of possible implementations. Indeed, many of these features may be combined in ways not specifically recited in the claims and / or disclosed in the specification. Although each dependent claim listed below may depend directly on only one claim, the disclosure of possible implementations includes each dependent claim in combination with every other claim in the claim set.

[0079] No element, act, or instruction used herein should be construed as critical or essential unless expressly described as such. Also, as used herein, the articles "a" and "an" and the term "set" are intended to include one or more items and may be used interchangeably with "one or more." When only one item is intended, the term "one" or similar terminology is used. Also, as used herein, terms such as "comprises," "having," "having," and the like are intended to be open-ended terms. Additionally, the phrase "based on" is intended to mean "at least in part" unless otherwise specified. [Explanation of symbols]

[0080] 1 Compressor 3 Heat exchanger (refrigerant condensation heat exchanger) 11 Heat exchanger (refrigerant-air heat exchanger) 12 Blower 15 Inversion element (first inversion element) 17 Expansion valve 23 Inversion element (second inversion element) 27 Heat exchanger (refrigerant-source heat exchanger) 36 Water Tank

Claims

1. 1. A heat pump system comprising: a compressor having a low pressure vapor refrigerant inlet and a high pressure vapor refrigerant outlet, the compressor being configured to compress low pressure vapor refrigerant passing from the inlet to the outlet of the compressor to a high pressure vapor refrigerant; a refrigerant condensation heat exchanger having an inlet connected to the high pressure vapor refrigerant outlet of the compressor and an outlet, the refrigerant condensation heat exchanger condensing the high pressure vapor refrigerant passing from the inlet to the outlet of the condensation heat exchanger and exchanging heat from the refrigerant to heat at least one of water for heating and water for domestic use; a refrigerant cooling heat exchanger having an inlet connected to the outlet of the condensing heat exchanger and an outlet, the refrigerant cooling heat exchanger condensing high pressure vapor refrigerant and further cooling high pressure liquid refrigerant passing from the inlet to the outlet of the cooling heat exchanger; an expansion valve having an inlet connected to the outlet of the cooling heat exchanger outlet and an outlet configured to generate a pressure drop in a high-pressure liquid refrigerant passing through the expansion valve to output one of a low-pressure liquid refrigerant or a two-phase gas-liquid mixed refrigerant; a refrigerant evaporation heat exchanger having an inlet connected to the expansion valve outlet and an outlet connected to the compressor inlet, the refrigerant evaporation heat exchanger being configured to evaporate at least low pressure liquid refrigerant passing from the inlet to the outlet of the evaporative heat exchanger to supply low pressure vapor refrigerant to the compressor; at least one blower for supplying one of cold air from the evaporative heat exchanger when the heat pump is in a cooling mode and hot air from the cooling heat exchanger when the heat pump is in a heating mode to a cooling and heating outlet; A heat pump system comprising:

2. 1. A heating and cooling system for a structure, the heating and cooling system comprising a heat pump; The heat pump comprises: a compressor for compressing a low pressure vapor refrigerant into a high pressure vapor refrigerant; a refrigerant condensing heat exchanger, the condensing heat exchanger utilizing heat exchanged from the high pressure vapor refrigerant to heat water and output one of a high pressure liquid refrigerant and a high pressure two-phase gas-liquid refrigerant, and water from a water storage tank provides at least one of hot water for heating the structure and hot water for home use; a refrigerant cooling heat exchanger for further cooling the high pressure liquid refrigerant and condensing the high pressure vapor refrigerant received from the condensing heat exchanger; an expansion valve connected to the cooling heat exchanger and configured to cause a pressure drop in the high pressure liquid refrigerant to output one of a low pressure liquid refrigerant and a low pressure two-phase gas-liquid refrigerant; a refrigerant evaporation heat exchanger connected to the expansion valve and evaporating the low-pressure liquid refrigerant to supply a low-pressure vapor refrigerant to the compressor; a first reversing element having a heating mode and a cooling mode, In the heating mode, the first reversing element directs refrigerant flow from the condensing heat exchanger to a refrigerant-to-air heat exchanger that functions as the refrigerant cooling heat exchanger, and the refrigerant evaporating heat exchanger is a refrigerant-to-source heat exchanger; a first reversal element, in the cooling mode, directing refrigerant flow from the condensing heat exchanger to the refrigerant-to-source heat exchanger that functions as the refrigerant cooling heat exchanger, and the refrigerant evaporating heat exchanger being the refrigerant-to-air heat exchanger; a second reversing element configured to reverse refrigerant flow through the refrigerant-to-source heat exchanger; and at least one blower coupled to the refrigerant-to-air heat exchanger for supplying one of cold air from the refrigerant-to-air heat exchanger and hot air from the refrigerant-to-air heat exchanger to the structure; A heating and cooling system comprising:

3. A method for supplying hot or cold air and hot water, comprising: compressing the low pressure vapor refrigerant into a high pressure vapor refrigerant by a compressor; condensing at least a portion of the high pressure vapor refrigerant by a refrigerant condensing heat exchanger to transfer heat from the refrigerant to at least one of the water for heating and water for domestic use to produce a high pressure liquid refrigerant; cooling the high pressure liquid refrigerant through a refrigerant cooling heat exchanger; expanding the cooled high pressure liquid refrigerant through an expansion valve to produce a cooled low pressure liquid refrigerant; evaporating the cooled low-pressure liquid refrigerant through a refrigerant evaporation heat exchanger to supply the low-pressure vapor refrigerant to the compressor; circulating air through at least one blower to supply one of the cold air from the evaporative heat exchanger and the hot air from the cooling heat exchanger to an outlet for cooling and heating; A method comprising:

4. The system of claim 2 , wherein the water heated in the condensing heat exchanger is circulated from a water storage tank.

5. 5. The system of claim 4, wherein the water in the water tank provides at least one of heat to a water source for domestic use and heat for heating a structure.

6. The system of claim 1 or 2, wherein the at least one blower is adjustable to control air flow and heat transfer.

7. a first reversing element configured to reverse the refrigerant flow between a heating mode and a cooling mode; In the heating mode, the cooling heat exchanger is a refrigerant-to-air heat exchanger and the refrigerant evaporation heat exchanger is a refrigerant-to-source heat exchanger; 2. The system of claim 1, wherein in said cooling mode, said cooling heat exchanger is said refrigerant-to-source heat exchanger and said refrigerant evaporative heat exchanger is said refrigerant-to-air heat exchanger.

8. The system of claim 7 further comprising a second reversing element configured to reverse refrigerant flow through the refrigerant-to-source heat exchanger.

9. The system of claim 7 , wherein the refrigerant-source heat exchanger is one of a ground source heat exchanger and an air source heat exchanger.

10. The system of claim 7 , wherein the refrigerant-source heat exchanger is one of a direct refrigerant-source heat exchanger and an indirect refrigerant-source heat exchanger.

11. 3. The system of claim 1 or 2, wherein the refrigerant exiting at least one of the refrigerant condensing heat exchanger and the expansion valve is a two-phase mixture.

12. 3. The system of claim 2, wherein the refrigerant cooling heat exchanger exchanges heat with a heat exchange medium that is colder than water that exchanges heat with the refrigerant in the refrigerant condensing heat exchanger.

13. 3. The system of claim 1 or 2, wherein the system is part of one of a residential heating and cooling system, a commercial heating and cooling system, and an industrial heating and cooling system.

14. a first reversing element having a heating mode and a cooling mode, In the heating mode, the first reversing element directs refrigerant flow from the condensing heat exchanger to a refrigerant-to-air heat exchanger that functions as the refrigerant cooling heat exchanger, and the refrigerant evaporating heat exchanger is a refrigerant-to-source heat exchanger; a first reversal element, in the cooling mode, directing refrigerant flow from the condensing heat exchanger to the refrigerant-to-source heat exchanger that functions as the refrigerant cooling heat exchanger, and the refrigerant evaporating heat exchanger being the refrigerant-to-air heat exchanger; a second reversing element configured to reverse refrigerant flow through the refrigerant-to-source heat exchanger; and The system of claim 1 further comprising:

15. The system of claim 14 , wherein the second reversal element is configured to create a counterflow of refrigerant through the refrigerant-to-source heat exchanger.

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