Systems and methods to switch operational modes of heat pump water heaters

Abstract

A water heating system including a storage tank, a heat pump assembly, and a controller is disclosed. The heat pump assembly may provide hot water to the storage tank. The heat pump assembly may be configured to operate in a single pass mode and a multi pass mode. The controller may switch an operational state of the heat pump assembly between the single pass mode and the multi pass mode based on one or more parameters, such as a hot water demand, ambient conditions, an inlet water temperature, and / or the like.

Description

COE-051-WO (92575-3143)SYSTEMS AND METHODS TO SWITCH OPERATIONAL MODES OF HEAT PUMPWATER HEATERSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to and the benefit of US provisional application No. 63 / 734, 380, filed December 16, 2024, which is hereby incorporated by reference herein in its entirety.FIELD

[0002] The present disclosure relates to systems and methods to optimally switch an operational mode of a heat pump water heater and more specifically to systems and methods to switch an operational state of a heat pump water heater between a single pass mode and a multi pass mode.BACKGROUND

[0003] Water heaters are generally used to provide a supply of heated water in a variety of applications, including residential, commercial, and industrial applications. A tank based water heater typically includes a storage tank that stores water that is heated by a heating source. The heating source may be, for example, a heat pump assembly, a solar heating unit, a gas heating unit, an electric heating unit, and / or the like.

[0004] A heat pump water heater typically includes a condenser heat exchanger that heats the water stored in the storage tank or provides hot water to the storage tank. Continuous efforts are being made to enhance the efficiency of the heat pump water heaters without affecting the user experience of drawing the required amount of hot water from the storage tank.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The detailed description is set forth with reference to the accompanying drawings. The use of the same reference numerals may indicate similar or identical items. VariousCOE-051-WO (92575-3143) embodiments may utilize elements and / or components other than those illustrated in the drawings, and some elements and / or components may not be present in various embodiments. Elements and / or components in the figures are not necessarily drawn to scale. Throughout this disclosure, depending on the context, singular and plural terminology may be used interchangeably.[0906| FIG. 1 depicts a block diagram of an exemplary first water heating system in accordance with one or more embodiments of the present disclosure.

[0007] FIG. 2 depicts a block diagram of an exemplary heat pump assembly in accordance with one or more embodiments of the present disclosure.

[0008] FIG. 3 depicts a block diagram of an exemplary second water heating system in accordance with one or more embodiments of the present disclosure.

[0009] FIG. 4 depicts a block diagram of an exemplary third water heating system in accordance with one or more embodiments of the present disclosure.

[0010] FIG. 5 depicts a block diagram of an exemplary fourth water heating system in accordance with one or more embodiments of the present disclosure.

[0011] FIG. 6 depicts a block diagram of a controller in accordance with one or more embodiments of the present disclosure.

[0012] FIG. 7 depicts a flow diagram of an exemplary method to switch an operational state of a water heating system in accordance with one or more embodiments of the present disclosure.DETAILED DESCRIPTION

[0013] The present disclosure is directed towards a water heating system that may include a storage tank, a heat pump assembly, a controller and a sensor unit. The storage tank may receive a supply of cold water from a utility water source and may transfer the water to the heat pump assembly. The heat pump assembly may heat the water received from the storage tank (“received water”) and may transfer the heated water back to the storage tank, which the storage tank may store. In an exemplary aspect, the storage tank may receive the supply of cold water at a storage tank bottom portion and may transfer the cold water to the heat pumpCOE-051-WO (92575-3143) assembly from the storage tank bottom portion. The heat pump assembly may transfer the heated water to a storage tank middle portion or a storage tank top portion (or any other portion in between) based on an operational state of the heat pump assembly. Consequently, the water temperature of the water in proximity to the storage tank bottom portion may be low (as it receives the cold water from the utility water source), and the water temperature of the water in proximity to the storage tank middle and top portions may be higher. In some aspects, the water temperature in the storage tank may be stratified, such that the water temperature may be highest at the storage tank top portion and lowest at the storage tank bottom portion.

[0014] In certain embodiments, the heat pump assembly may include a first heat exchanger and a second heat exchanger. The second heat exchanger may output a high-pressure refrigerant in a liquid state. In some aspects, the second heat exchanger may be a condenser. The heat pump assembly may further include an expansion device (e.g., an expansion valve or a capillary) that may receive the refrigerant from the second heat exchanger. Hereinafter, in the present disclosure, the expansion device is referred to as expansion valve; however, such terminology should not be construed as limiting. The expansion valve may reduce the pressure and temperature of the received refrigerant and output a low-pressure, low-temperature refrigerant. The first heat exchanger may receive the refrigerant from the expansion valve and may output the refrigerant in a vapor state. In some aspects, the first heat exchanger may be an evaporator. In some aspects, the evaporator may include a fan that may draw heat from ambient environment / air and may blow hot air towards the refrigerant received from the expansion valve, thereby heating and vaporizing the refrigerant. The heat pump assembly may further include a compressor that may receive the refrigerant from the first heat exchanger and output the refrigerant in a high pressure, high temperature vapor state. The second heat exchanger may receive the refrigerant from the compressor, thus completing the vapor compression cycle.

[0015] As will be appreciated, the refrigerant circuit may additionally include a reversing valve, which may reverse the flow of refrigerant described above based on a mode of operation of the heat pump assembly. For the sake of simplicity, a single flow direction of the refrigerant is described above.COE-051-WO (92575-3143)

[0016] In some aspects, the second heat exchanger (i.e., the condenser) may be disposed outside of the storage tank and may convert the vapor state refrigerant received from the compressor into a liquid state. The heat that the condenser generates while converting the refrigerant from the vapor state to the liquid state is used by the heat pump assembly to heat the water received from the storage tank. The system may further include a recirculation pump unit that may transfer or pump the water heated by the condenser back into the storage tank at the storage tank’s middle or top portion, as described above.[00.17] In some aspects, the heat pump assembly may be configured to operate in multiple operational states / modes (e g., in a single pass mode and a multi pass mode). The heat pump assembly may heat the received water to a set-point temperature and provide the hot water at the set-point temperature to the storage tank (via the recirculation pump unit) when the heat pump assembly operates in the single pass mode. In some aspects, the heat pump assembly may provide the hot water at the set-point temperature to the storage tank’s top portion when the heat pump assembly operates in the single pass mode.

[0018] On the other hand, the heat pump assembly may incrementally heat the received water (and may not heat the received water to the set-point temperature) and recirculate an incrementally heated water between the heat pump assembly and the storage tank when the heat pump assembly operates in the multi pass mode. Since the heat pump assembly incrementally heats the received water in the multi pass mode (e.g., incrementally heats the water by 10 or 12 degrees Fahrenheit, as opposed to directly heating the water to the set point temperature), the system efficiency is higher when the heat pump assembly operates in the multi pass mode as compared to the single pass mode. In some aspects, the heat pump assembly may provide the incrementally heated water to the storage tank’s middle portion when the heat pump assembly operates in the multi pass mode.

[0019] The controller may determine an optimal operational state / mode of the heat pump assembly based on one or more parameters, such as a hot water demand, ambient conditions, an inlet water temperature, a water flow rate, a user input, and / or the like. Responsive to determining the optimal operational state, the controller may transmit command signals to one or more heat pump assembly components to cause the heat pump assembly to operate in theCOE-051-WO (92575-3143) determined optimal operational state. The controller may determine one or more of these parameters described above based on inputs obtained from the sensor unit, which may include a plurality of sensors including, but not limited to, tank water temperature sensors, an inlet water temperature sensor, a water flowrate sensor, ambient temperature and humidity level sensors, and / or the like.[0(120 j In an exemplary aspect, the controller may cause the heat pump to operate in an optimal operational state such that the system’s efficiency may be enhanced, while at the same time ensuring that the user’s hot water demand is met. For example, the controller may cause the heat pump assembly to operate in the single pass mode when the user requires hot water immediately. In this case, since the heat pump assembly incrementally heats the received water in the multi pass mode and hence may take more time to heat the water, the controller may cause the heat pump assembly to operate in the single pass mode as opposed to the multi pass mode as the user requires the hot water immediately and hence the multi pass mode may not be appropriate. On the other hand, when the user does not require the hot water immediately and may require it at a future time, the controller may cause the heat pump assembly to operate in the multi pass mode to optimize / enhance the system efficiency.

[0021] As another example, the controller may cause the heat pump assembly to operate in the multi pass mode when the ambient temperature and / or the inlet water temperature may be too low for the operation in the single pass mode to be feasible. The controller may further cause the heat pump assembly to operate in the single pass mode or the multi pass mode based on user selection of the operational state / mode of the system (e.g., via a system user interface).

[0022] In additional embodiments, the system may include or be integrated with a secondary heating source that may “augment” the heat pump assembly in heating the water in the storage tank. Examples of the secondary heating source include, but are not limited to, a solar heating unit, a gas heating unit, an electric heating unit, and / or the like. In some aspects, the controller may cause the secondary heating source to augment the heat pump assembly in heating the water when the heat pump assembly operates in the multi pass mode. In this case, the controller may select a preferred operational state / mode of the system based on the overallCOE-051-WO (92575-3143) efficiency of the system. For instance, if the system efficiency while operating in the singlepass mode is higher than the operation in the multi-pass mode and the usage of the secondary heating source, the controller may cause the heat pump assembly to operate in the single pass mode, and vice versa.

[0023] In further embodiments, the controller may estimate a predicted demand of hot water at a future time, which may be indicative of a predicted amount of hot water that the user may require at the future time. Responsive to estimating the predicted hot water demand, the controller may determine an optimal height to inject the hot water into the storage tank from the heat pump assembly based on the predicted hot water demand and a time duration remaining to heat the water in the storage tank. The controller may then cause the heat pump assembly to inject the hot water into the storage tank at the determined optimal height, so that appropriate amount of hot water may be stored in proximity to the storage tank’s top portion by the future time and the user may conveniently obtain the hot water from the system without having to wait.

[0024] Although certain examples of the disclosed technology are explained in detail herein, it is to be understood that other examples, embodiments, and implementations of the disclosed technology are contemplated. Accordingly, it is not intended that the disclosed technology is limited in its scope to the details of construction and arrangement of components expressly set forth in the following description or illustrated in the drawings. The disclosed technology can be implemented in a variety of examples and can be practiced or carried out in various ways. In particular, the presently disclosed subject matter is described in the context of being a system and method for switching an operational state / mode of a water heating system. The present disclosure, however, is not so limited, and can be applicable in other contexts. Furthermore, the present disclosure can include other fluid heating systems configured to heat a fluid other than water such as process fluid heaters used in industrial applications. Such implementations and applications are contemplated within the scope of the present disclosure. Accordingly, when the present disclosure is described in the context of being a system and method for switching an operational state / mode of a water heating system, it will be understood that other implementations can take the place of those referred to.COE-051-WO (92575-3143)

[0025] Although the term “water” is used throughout this specification, it is to be understood that other fluids may take the place of the term “water” as used herein. Therefore, although described as a system and method to heat water, it is to be understood that the systems and methods described herein can apply to fluids other than water. Further, it is also to be understood that the term “water” can replace the term “fluid” as used herein unless the context clearly dictates otherwise. More so, the terms “cold” and “hot” are relative and may mean different degrees of varying temperatures and ranges based on the context. Thus, the terms “cold” and “hot” should not be limited to any temperature or temperature range.

[0026] Turning now to the drawings, FIG. 1 depicts a block diagram of an exemplary first water heating system 100 (or water heater 100 or system 100) in accordance with one or more embodiments of the present disclosure. While describing FIG. 1, references will be made to FIG. 2.

[0027] The system 100 may include a plurality of units including, but not limited to, a storage tank 102, a heat pump assembly 104, a controller 106 and a sensor unit 108. The system 100 may include a plurality of additional components that are not shown in FIG. 1 for the sake of simplicity and conciseness (e.g., a housing, tank inlet and outlet ports, etc.).

[0028] The storage tank 102 may receive a supply of cold water 110 (e.g., from a utility water source) and output a supply of hot water 112. In an exemplary aspect, the storage tank 102 may output the hot water 112 from a top portion of the storage tank 102 and receive the cold water 110 in a bottom portion (or a side portion) of the storage tank 102. Further, the storage tank 102 may store the received water.10029] The storage tank 102 may be of any size, shape, or configuration based on the water heating system application. For example, the storage tank 102 may be sized for common residential use or for commercial or industrial use that may require greater amounts of heated water. Furthermore, the storage tank 102 may be made of any suitable material for storing hot water, including copper, carbon steel, stainless steel, ceramics, polymers, composites, or any other suitable material. The storage tank 102 may also be treated or lined with a coating to prevent corrosion and leakage. A suitable treating or coating will be capable of withstanding the temperature and pressure of the system 100 and may include, as non-limiting examples,COE-051-WO (92575-3143) glass enameling, galvanizing, thermosetting resin-bonded lining materials, thermoplastic coating materials, cement coating, or any other suitable treating or coating for the application.

[0030] The heat pump assembly 104 may receive a supply of water 114 from the storage tank 102 and heat the received water. The heat pump assembly 104 may further provide hot water to the storage tank 102, which the storage tank 102 may store. In some aspects, the heat pump assembly 104 may receive the water 114 from the bottom portion of the storage tank 102 (i.e., the portion at which the storage tank 102 receives the cold water 110), as shown in FIG. 1. In other aspects (not shown), the heat pump assembly 104 may receive the water 114 from any other portion of the storage tank 102, e g., closer to a middle portion of the storage tank 102.[00311 The heat pump assembly 104 may include a plurality of components including, but not limited to, a first heat exchanger 202, a compressor 204, a second heat exchanger 206 and an expansion device 208 (hereinafter referred to as expansion valve 208) connected in by refrigerant tubing 210 through which, during heat pump operation, a refrigerant may flow in the indicated clockwise direction, as shown in FIG. 2. Specifically, the refrigerant may sequentially flow from an outlet of the compressor 204, through the second heat exchanger 206, through the expansion valve 208, through the first heat exchanger 202, and back to an inlet of the compressor 204.

[0032] In some aspects, the heat pump assembly 104 may additionally include a reversing valve (not shown) through which the flow of refrigerant shown in FIG. 2 and described above may be reversed. Depending on the mode of operation in which the heat pump assembly 104 may be operating, the flow of refrigerant may be reversed. Consequently, the flow of refrigerant depicted in FIG. 2 should not be construed as limiting.

[0033] The refrigerant may be selected from a variety of materials. The refrigerant may be any material capable of supplying favorable thermodynamic properties to a heating system. The refrigerant, for example, may be selected based on a desired boiling point, a high heat of vaporization, a moderate liquid density, a high critical temperature, and / or other aspects. Accordingly, the refrigerant may be any chlorofluorocarbon, chlorofluoroolefin, hydrochlorofluorocarbon, hydrochlorofluoroolefin, hydrofluorocarbon, hydrofluoroolefin,COE-051-WO (92575-3143) hydrochlorocarbon, hydrochloroolefin, hydrocarbon, hydroolefin, perfluorocarbon, perfluoroolefin, perchlorocarbon, perchloroolefin, halon, or haloalkane. For example, the refrigerant may be any refrigerant designated as such by, and compliant with, the standards, rules, and regulations set forth by the American Society of Heating, Refrigerating, and Air- Conditioning Engineers (ASHRAE) (e.g., ASHRAE Standard 34-2019). For example, the refrigerant may be R-410A or R-134a. In some embodiments, the refrigerant may be or may include a hydrofluorool efin, such as HFO-1234yf or blends thereof, including R-454B. 0034] In some aspects, the first heat exchanger 202 may be an evaporator (having evaporator coils, not shown) and the second heat exchanger 206 may be a condenser having condenser coils. Hereinafter, the first heat exchanger 202 is referred to as evaporator 202, and the second heat exchanger 206 is referred to as condenser 206.

[0035] The compressor 204 may output the refrigerant in a vapor state towards the condenser 206, via the refrigerant tubing 210. The refrigerant output from the compressor 204 may be at a high temperature and high pressure state. The condenser 206 may receive the refrigerant from the compressor 204 via the refrigerant tubing 210 and may convert the refrigerant into a liquid state. In some aspects, the heat that the condenser 206 dissipates while changing the refrigerant phase from vapor to liquid may be used to heat water that may be circulating in the heat pump assembly 104. In an exemplary aspect, the condenser 206 may be disposed external to the storage tank 102, and the condenser 206 may heat the water 114 that the heat pump assembly 104 receives from the storage tank 102. The heat pump assembly 104 may then provide the hot water heated by the condenser 206 to the storage tank 102.10036] The condenser 206 may output the refrigerant in a liquid state towards the expansion valve 208 via the refrigerant tubing 210. The refrigerant output from the condenser 206 may be at a high pressure and medium-to-high temperature state. The expansion valve 208 may receive the refrigerant from the condenser 206 and may output the refrigerant in a low pressure, low temperature state towards the evaporator 202 via the refrigerant tubing 210. The refrigerant output from the expansion valve 208 may be in a mixture of liquid and vapor states.

[0037] The evaporator 202 may receive the refrigerant from the expansion valve 208 and may convert the refrigerant into a low pressure, vapor state refrigerant. The evaporator 202COE-051-WO (92575-3143) may include a fan (not shown) that may draw air from ambient environment and blow it towards the evaporator 202. The evaporator 202 may draw heat / warmth from the air that is received from the fan and may transfer the warmth towards the refrigerant received from the expansion valve 208, thereby vaporizing the refrigerant. The evaporator 202 may output the refrigerant in a vapor state towards the compressor 204 via the refrigerant tubing 210. The compressor 204 may receive the refrigerant from the evaporator 202 and may “compress” the refrigerant to output the refrigerant in a high pressure, high temperature state, as described above.

[0038] In some aspects, the compressor 204 may be a pump that provides additional pressure to the refrigerant to enable the refrigerant to flow through the defined path, as indicated in FIG. 2. In this manner, the refrigerant flows in the heat pump assembly 104, facilitating the heating of the water 114 through the condenser 206.

[0039] The compressor 204 may be of any type. For example, the compressor 204 may be a positive displacement compressor, a reciprocating compressor, a rotary screw compressor, a rotary vane compressor, a rolling piston compressor, a scroll compressor, a diaphragm compressor, a dynamic compressor, an axial compressor, or any other form of compressor that can be integrated into the heat pump assembly 104 for the particular application. In an exemplary aspect, the compressor 204 may be a variable speed compressor that may adjust its speed (e.g., adjust a speed / Rotations-Per-Minute (RPM) of a compressor motor) based on a demand of compressed refrigerant or a required heating capacity in the heat pump assembly 104. As an example, the compressor 204 may increase its speed when the heat pump assembly 104 heats the water 114 quickly to a higher set point temperature (or at a higher desired water temperature). As another example, the compressor 204 may decrease its speed when the heat pump assembly 104 heats the water 114 slowly and / or incrementally by a smaller temperature difference (e.g., to heat the water 114 by 10-12 degrees Fahrenheit). In some aspects, the controller 106 may be communicatively coupled with the compressor 204, and may transmit command signals to the compressor 204 to adjust the compressor speed.

[0040] In an exemplary aspect, the heat pump assembly 104 may further include a recirculation pump unit 116 and / or a valve unit 118, as shown in FIG. 1. In other aspects, theCOE-051-WO (92575-3143) recirculation pump unit 116 and / or the valve unit 118 may not be part of the heat pump assembly 104 but may be part of the system 100. In further aspects, the system 100 / heat pump assembly 104 may include only the recirculation pump unit 116 and may not include the valve unit 118. In other aspects, the system 100 / heat pump assembly 104 may include both the recirculation pump unit 116 and the valve unit 118, as shown in FIG. 1.[0(1411 The recirculation pump unit 116 may include one or more pumps that may control a flow of hot water from the heat pump assembly 104 to the top portion and the middle portion of the storage tank 102 (the middle portion may be between the top portion and the bottom portion of the storage tank 102). For example, the recirculation pump unit 116 may include one pump (e.g., a first pump) that may enable the flow of hot water to the top portion of the storage tank 102, and another pump (e.g., a second pump) that may enable the flow of hot water to the middle portion of the storage tank 102. In some aspects, only one pump from the first and second pumps may operate in the recirculation pump unit 116 so that the heat pump assembly 104 may provide / inject the hot water to either the top portion or the middle portion of the storage tank 102.[00421 In alternative aspects, the recirculation pump unit 116 may include a single pump that may enable the flow of hot water from the heat pump assembly 104 to the storage tank 102. In this case, the system 100 / heat pump assembly 104 may include the valve unit 118 that may receive the hot water from the recirculation pump unit 116 and control the flow of hot water to the top portion and the middle portion of the storage tank 102. The valve unit 118 may include one or more valves (e.g., on-off valves, proportional valves, three-way valves, etc.) that may inject the hot water received from the recirculation pump unit 116 into either the top portion or the middle portion of the storage tank 102.[0043 j In some aspects, the controller 106 may be communicatively coupled with a plurality of system components, e.g., the compressor 204, the recirculation pump unit 116, the valve unit 118, the sensor unit 108, and / or the like, and control their operations. For example, the controller 106 may transmit command signals to the compressor 204, the recirculation pump unit 116 and / or the valve unit 118 to control their operations, as described later in the description below.COE-051-WO (92575-3143)

[0044] The sensor unit 108 may include a plurality of sensors including, but not limited to, one or more temperature sensors 120, one or more flowrate sensors, ambient temperature and / or humidity sensors (not shown), and / or the like. The temperature sensors 120 may be located at different locations in the storage tank 102 along a length of the storage tank 102, and may measure temperature of water (e.g., hot water) stored at different portions of the storage tank 102. For example, the temperature sensors 120 may measure the water temperature at the bottom, middle and top portions (and / or other portions) of the storage tank 102. The flowrate sensors may detect a flow rate of water into or out of the storage tank 102. For example, the flowrate sensors may detect the flow rate of the cold water 1 10 and / or the hot water 112. The ambient temperature and / or humidity sensors may measure / detect ambient conditions. For example, the ambient temperature and / or humidity sensors may measure the ambient temperature, the ambient humidity level, and / or the like. The sensor unit 108 may transmit inputs from the sensors described above to the controller 106 at a predefined frequency.

[0045] In some aspects, the heat pump assembly 104 may operate in multiple operational modes / states, e.g., a single pass mode and a multi pass mode, based on command signals that the controller 106 provides / transmits to the heat pump assembly components. In an exemplary aspect, the heat pump assembly 104 may heat the water 114 to a set-point temperature (or a desired water temperature set by a system user) and provide hot water 122 at the set-point temperature to the storage tank 102 when the heat pump assembly 104 operates in the single pass mode. In an exemplary aspect, the heat pump assembly 104 may provide the hot water 122 at the set-point temperature to the top portion of the storage tank 102 (as shown in FIG. 1) when the heat pump assembly 104 operates in the single pass mode.

[0046] It may be appreciated that since the hot water 112 is output from the storage tank’s top portion for user’s consumption (as shown in FIG. 1 and described above), if the heat pump assembly 104 directly provides the hot water 122 at the set-point temperature to the storage tank’s top portion, the system user may quickly receive the hot water at the temperature desired by the user. In some aspects, the storage tank 102 stores the water in such a manner that the storage tank’s top portion stores the hottest water (i.e., the water at a higher temperature or the set-point temperature) and the water temperature gradually decreases along the length of theCOE-051-WO (92575-3143) storage tank 102 towards the bottom portion (since the bottom portion receives the cold water 110). Consequently, the storage tank’s top portion has water at the highest temperature (typically at or close to the set-point temperature) and the storage tank’s bottom portion has water at the lowest temperature. For example, if the set-point temperature is 120 degrees Fahrenheit, the storage tank’s top portion may store hot water at or close to 120 degrees Fahrenheit and the storage tank’s bottom portion may store water at a relatively cooler temperature (e.g., 60-90 degrees Fahrenheit, depending on the temperature of the cold water 110). Stated another way, the temperature of hot water in the storage tank 102 may be stratified along the length of the storage tank 102.

[0047] Since the water stored at the storage tank’s top portion is hottest, the heat pump assembly 104 provides the hot water 122 at the set-point temperature directly to the top portion of the storage tank 102 when the heat pump assembly 104 operates in the single pass mode, so that the temperature of the hot water 122 does not drop and the user receives the hot water 112 at the set-point temperature immediately. It may be appreciated that if the heat pump assembly 104 provides the hot water 122 at the set-point temperature to any other portion of the storage tank 102 (e.g., at the middle portion), the temperature of the hot water 122 may drop as the water present at the middle portion may be at a lower temperature, which may cause a drop in the temperature of the hot water 122. Therefore, in this case, the user may not immediately receive the hot water 112 at the set-point temperature and may have to wait till the entire volume of water stored above the middle portion (till the top portion) reaches the set-point temperature. Therefore, when the user desires the hot water 112 at the set-point temperature quickly, the heat pump assembly 104 operates in the single pass mode so that the storage tank’s top portion receives the hot water 122 at the set-point temperature directly (and hence the user may quickly get the hot water 112 at the set-point temperature from the storage tank’s top portion). In some aspects, the storage tank 102 is of a relatively smaller size when the heat pump assembly 104 operates in the single pass mode, as the storage tank 102 directly receives the hot water 122 at the storage tank’s top portion, from where the user receives the hot water 112.COE-051-WO (92575-3143)

[0048] In an exemplary aspect, the controller 106 may transmit one or more command signals to the heat pump assembly components to enable the heat pump assembly 104 to operate in the single pass mode, when the controller 106 desires the heat pump assembly 104 to operate in the single pass mode. For example, the controller 106 may transmit a command signal to the compressor 204 to cause the compressor 204 to operate at a greater speed (to quickly heat the water 114), to enable the heat pump assembly 104 to operate in the single pass mode. The controller 106 may transmit another command signal to the first pump of the recirculation pump unit 116 described above to cause the first pump to enable the flow of hot water 122 into the storage tank’s top portion (when the recirculation pump unit 116 includes the first and second pumps, and the system 100 / heat pump assembly 104 does not include the valve unit 118). Furthermore, the controller 106 may transmit another command signal to the valve unit 118 to cause the valve unit 118 to enable the flow of hot water 122 into the storage tank’s top portion (when the recirculation pump unit 116 includes a single pump, and the system 100 / heat pump assembly 104 includes the valve unit 118).[0049 j In some aspects, the heat pump assembly 104 may incrementally heat the water 114 and recirculate an incrementally heated water 124 between the heat pump assembly 104 and the storage tank 102 when the heat pump assembly 104 operates in the multi pass mode. For example, the heat pump assembly 104 may incrementally heat the water 114 by a predefined small temperature difference / increment (e.g., by 10-12 degrees Fahrenheit, which may be based on the compressor speed), and then inject the incrementally heated water 124 back to the storage tank 102 when the heat pump assembly 104 operates in the multi pass mode. In this case, the heat pump assembly 104 may not directly heat the water 114 to the set-point temperature (as is the case with the single pass mode) but may instead incrementally heat the water 114 by the predefined small temperature increment.[0050 j Responsive to injecting the incrementally heated water 124 back to the storage tank 102, the heat pump assembly 104 may receive further water 114 from the storage tank 102, and then again heat the water 114 incrementally and inject the incrementally heated water 124 back to the storage tank 102. The heat pump assembly 104 may perform this water heating and recirculation step multiple times iteratively till the temperature of the water in the storage tankCOE-051-WO (92575-3143)102 reaches to the set-point temperature (at which point the heat pump assembly 104 may start to operate in the single pass mode, if required).

[0051] In some aspects, the heat pump assembly 104 may provide the incrementally heated water 124 to the middle portion of the storage tank 102 (or any other portion between the top and bottom portions of the storage tank 102) when the heat pump assembly 104 operates in the multi pass mode. As described above, since the water stored at the storage tank’s top portion (from where the user obtains the hot water 112) is hottest, the heat pump assembly 104 may not significantly “affect” the hot water temperature at the storage tank’s top portion when the heat pump assembly 104 injects the incrementally heated water 124 to the middle portion of the storage tank 102. Therefore, the heat pump assembly 104 injects the incrementally heated water 124 to the middle portion of the storage tank 102 when the heat pump assembly 104 operates in the multi pass mode. In this manner, the storage tank’s top portion may still provide the hot water 112 at the temperature desired by the user when the heat pump assembly 104 is incrementally / slowly heating the water stored in the storage tank 102 by injecting the incrementally heated water 124 to the middle portion of the storage tank 102.

[0052] Conventionally, the storage tank 102 is of a relatively larger size when the heat pump assembly 104 operates in the multi pass mode. However, since the heat pump assembly 104, as disclosed in the present disclosure, may operate in both the single pass mode and the multi pass mode, the system 100 ensures that the heat pump assembly 104 can operate in the multi pass mode even when the storage tank 102 is of a relatively smaller size.

[0053] In may be appreciated that while the heat pump assembly 104 may immediately (or near immediately) provide the hot water 122 at the set-point temperature to the storage tank 102 when the heat pump assembly 104 operates in the single pass mode, the heat pump assembly 104 may not be able to immediately heat the water in the storage tank 102 to the setpoint temperature and may take more time to heat the water when the heat pump assembly 104 operates in the multi pass mode (since the water is incrementally heated in the multi pass mode). Consequently, the controller 106 may cause the heat pump assembly 104 to operate in the multi pass mode when the user does not immediately require hot water at the set point temperature (and make require the hot water after some time).COE-051-WO (92575-3143)

[0054] In some aspects, since the heat pump assembly 104 incrementally heats the water 114 in the multi pass mode, the heat pump assembly operation is more efficient (i.e., the system efficiency is enhanced as less energy is required to heat the water 114) when the heat pump assembly 104 operates in the multi pass mode as compared to the single pass mode.

[0055] In an exemplary aspect, the controller 106 may transmit one or more command signals to the heat pump assembly components to enable the heat pump assembly 104 to operate in the multi pass mode, when the controller 106 desires the heat pump assembly 104 to operate in the multi pass mode. For example, the controller 106 may transmit a command signal to the compressor 204 to cause the compressor 204 to operate at a lower speed (to incrementally heat the water 114, and hence save energy), to enable the heat pump assembly 104 to operate in the multi pass mode. The controller 106 may transmit another command signal to the second pump of the recirculation pump unit 116 described above to cause the second pump to enable the flow of heated water 124 to the storage tank’s middle portion (when the recirculation pump unit 116 includes the first and second pumps, and the system 100 / heat pump assembly 104 does not include the valve unit 118). Furthermore, the controller 106 may transmit another command signal to the valve unit 118 to cause the valve unit 118 to enable the flow of heated water 124 to the storage tank’s middle portion (when the recirculation pump unit 116 includes a single pump, and the system 100 / heat pump assembly 104 includes the valve unit 118).[0(156] In operation, the controller 106 may switch the operational state / mode of the heat pump assembly 104 between the single pass mode and the multi pass mode based on one or more parameters. In an exemplary aspect, the controller 106 may switch the operational state / mode of the heat pump assembly 104 by transmitting command signals to the compressor 204 (e g., to adjust its speed), the recirculation pump unit 116 and the valve unit 118, as described above. Examples of such parameters include, but are not limited to, a hot water demand from the system 100, ambient conditions, an inlet water temperature of the cold water 110, a water flow rate into or from the system 100, a user input, an amount of hot water at the set point temperature already present at the storage tank’s top portion, an estimated amount of time required to heat water in the storage tank 102 to the set point temperature, and / or the like.COE-051-WO (92575-3143)

[0057] In some aspects, the controller 106 may determine the inlet water temperature, the water flow rate, the ambient conditions, the amount of hot water at the set point temperature already present at the storage tank’s top portion, etc. based on the inputs that the controller 106 obtains from the sensor unit 108, as described above. Further, the controller 106 may determine the hot water demand based on the user’s action of drawing the hot water 112 from the system 100, or the controller 106 may itself predict the hot water demand based on historical hot water usage pattern associated with the system 100 (information of which may be stored in a controller memory, shown as memory 610 in FIG. 6). In some aspects, the hot water demand may be indicative of a difference between an amount of hot water requested by the user and the amount of hot water at the set point temperature already available in the storage tank 102 (e.g., in proximity to the storage tank’s top portion). The hot water demand may be further indicative of a time required to heat the remaining amount of water associated with the difference of the hot water requested by the user and the hot water at the set point temperature already available in the storage tank 102.[0058j Exemplary scenarios in which the controller 106 may switch the operational state / mode of the heat pump assembly 104 are described above. The examples described below should not be construed as limiting.

[0059] In an exemplary embodiment, the controller 106 may switch the operational state of the heat pump assembly 104 to the single pass mode when the hot water demand is high (e.g., greater than a predefined threshold). For example, the controller 106 may switch the operational state of the heat pump assembly 104 to the single pass mode when the user desires a high amount of hot water within a relatively short time. On the other hand, the controller 106 may switch the operational state of the heat pump assembly 104 to the multi pass mode when the hot water demand is low (e.g., lower than the predefined threshold). For example, the controller 106 may switch the operational state of the heat pump assembly 104 to the multi pass mode when the user desires relatively less amount of hot water or the user does not immediately require the hot water. As described above, the efficiency of the system 100 / heat pump assembly 104 is enhanced when the heat pump assembly 104 operates in the multi pass mode.COE-051-WO (92575-3143)

[0060] In another exemplary embodiment, the controller 106 may switch the operational state of the heat pump assembly 104 between the single pass mode and the multi pass mode based on user input. In this case, the user may provide the user input (e.g., select a preferred operational state / mode) via a system user interface (not shown).

[0061] In yet another exemplary embodiment, the controller 106 may switch the operational state of the heat pump assembly 104 based on ambient conditions, the inlet water temperature of the cold water 110, and / or the water flow rate into or from the system 100. For example, the controller 106 may switch the operational state of the heat pump assembly 104 to the multi pass mode when the ambient temperature and humidity level may be high (e.g., greater than a first threshold), without affecting the system’s hot water delivery to the user. It may be appreciated that the heat pump assembly’s heating capacity is enhanced when the ambient temperature and humidity level are high. Therefore, the controller 106 may “use” this enhanced heat pump assembly’s heating capacity when the ambient temperature and humidity level are high and cause the heat pump assembly 104 to operate in the multi pass mode (thereby enhancing the system efficiency), as the heat pump assembly operation in the single pass mode may not be required when the heat pump assembly’s heating capacity is already high.

[0062] As another example, the controller 106 may switch the operational state of the heat pump assembly 104 to the multi pass mode when the ambient temperature and humidity level may be low (e.g., lower than a second threshold), without compromising on the efficiency and savings of the system 100 and / or affecting the system’s hot water delivery to the user. It may be appreciated that if the ambient temperature may be very low, the heat pump assembly 104 may not be able to quickly heat the water 114 to the set point temperature and hence may not be able to efficiently operate in the single pass mode. Consequently, when the ambient temperature is low, the controller 106 may switch the operational state of the heat pump assembly 104 to the multi pass mode. In this case, the controller 106 may further cause a secondary heating source to “augment” the heat pump assembly 104 in heating the water in the storage tank 102 when the heat pump assembly 104 operates in the multi pass mode. TheCOE-051-WO (92575-3143) concept of using the secondary heating source is described later in the description below in conjunction with FIG. 3.

[0063] As yet another example, the controller 106 may switch the operational state of the heat pump assembly 104 to the multi pass mode when the inlet water temperature of the cold water 110 may be too cold (e.g., less than a predefined temperature threshold) for the single pass mode to be feasible. In this case, the controller 106 may cause the heat pump assembly 104 to operate in the multi pass mode till the inlet water temperature increases above the predefined temperature threshold, at which point the controller 106 may switch the operational state to the single pass mode (if required based on the hot water demand). As yet another example, the controller 106 may switch the operational state of the heat pump assembly 104 to the multi pass mode when the inlet water flow rate may be too high (e.g., greater than a predefined flowrate threshold) for the single pass mode to be feasible.10064] In some aspects, the controller 106 switches the operational state / mode of the heat pump assembly 104 by taking into consideration technical / safety factors. For instance, the controller 106 ensures that the compressor 204 operates within its safety envelope and within its frequency range. In freezing conditions, the controller 106 may enable the system’s defrost control, limiting the freedom of switching between the single pass mode and the multi pass mode. In some aspects, during the defrost control, the water flow rate across the condenser 206 may be limited to promote the system defrost, and hence the operation of the heat pump assembly 104 cannot be optimized based on the control strategies described above. In this case, the controller 106 may choose the operational mode giving priority to these technical / safety factors, and, if the system 100 cannot keep up with the hot water demand, additional options may be considered. Examples of such additional options include, but are not limited to, addition of a secondary heating source (as described later below in conjunction with FIG. 3) and / or connection of multiple storage tanks similar to the storage tank 102 in the system 100.

[0065] For the option of the multiple storage tanks described above (not shown in FIG. 1), the system operator may install multiple storage tanks in the system 100 in series or in parallel. The controller 106 may implement similar control strategies of injecting hot water at different portions of the storage tanks for all the storage tanks, or a portion of storage tanks. In the latterCOE-051-WO (92575-3143) case, as an example, a first set of storage tanks may support multiple operational states / modes as described above, a second set of storage tanks may support only the single pass mode, a third set of storage tanks may support only the multi pass mode, and / or a fourth set of storage tanks may only be used for water storage purpose (e.g., as a back-up hot water reservoir). The controller 106 may cause the heat pump assembly 104 (or multiple heat pump assemblies if the system 100 includes multiple heat pump assemblies) to inject hot water at different portions of the storage tanks, based on the operational states the respective storage tanks support. 0066] FIG. 3 depicts a block diagram of an exemplary second water heating system 300 (or system 300) in accordance with one or more embodiments of the present disclosure. The system 300 may be similar to the system 100 described above; however, the system 300 may additionally include a secondary water heating source 302 or a secondary heating source 302. The secondary heating source 302 may integrate with the system 300 and may heat the water, similar to the heat pump assembly 104. Examples of the secondary heating source 302 include, but are not limited to, a solar heating unit, a gas heating unit, an electric heating unit, and / or the like. Similar to the heat pump assembly components described above, the secondary heating source 302 may also communicatively couple with the controller 106. The controller 106 may control the operation of the secondary heating source 302 by transmitting command signals to the secondary heating source 302.

[0067] The secondary heating source 302 may “augment” the heat pump assembly 104 in providing the hot water (e.g., the heated water 124) to the storage tank 102, based on the parameters described below. In some aspects, the secondary heating source 302 may provide additional hot water to the recirculation pump unit 116, which may be injected into the storage tank’s middle portion, when the controller 106 commands the secondary heating source 302 to augment the heat pump assembly 104 in providing hot water to the storage tank 102. In other aspects, the secondary heating source 302 may provide additional hot water directly to the storage tank’s middle portion, when the controller 106 commands the secondary heating source 302 to augment the heat pump assembly 104 in providing hot water to the storage tank 102. In yet another aspect, the secondary heating source 302 may provide additional heat in proximity to the condenser 206 to enable the heat pump assembly 104 to more effectively heat water (orCOE-051-WO (92575-3143) heat water at an enhanced rate / capacity), when the controller 106 commands the secondary heating source 302 to augment the heat pump assembly 104 in providing hot water to the storage tank 102. The example ways described above in which the secondary heating source 302 augments the heat pump assembly’s heating capacity should not be construed as limiting.

[0068] In some aspects, the controller 106 may command the secondary heating source 302 to augment the heat pump assembly 104 or cause the secondary heating source 302 to provide additional hot water to the storage tank 102 based on the parameters described above (e.g., the ambient conditions, the hot water demand, the inlet water temperature, etc.). Further, the controller 106 may command the secondary heating source 302 to augment the heat pump assembly 104 or cause the secondary heating source 302 to provide additional hot water to the storage tank 102 when the heat pump assembly 104 operates in the multi pass mode.

[0069] The controller 106 may choose the preferred operational state / mode of the system 200 (e.g., whether to cause the secondary heating source 302 to augment the heat pump assembly 104 or not, or cause the heat pump assembly 104 to operate in the single pass mode) based on the parameters described above to optimize the overall system efficiency. For example, if the system efficiency while operating in the single-pass mode is higher than the system efficiency while operating in the multi-pass mode and using the secondary heating source 302 (while meeting the hot water demand in both cases), the controller 106 may cause the heat pump assembly 104 to operate in the single pass mode. On the other hand, if the system efficiency while operating in the multi-pass mode and using the secondary heating source 302 is greater than the system efficiency while operating in the single-pass mode (while meeting the hot water demand in both cases), the controller 106 may cause the heat pump assembly 104 to operate in the multi pass mode and cause the secondary heating source 302 to augment the heat pump assembly 104. In some aspects, the system efficiency may be defined as a ratio of the heated water provided by the system 200 and the amount of energy consumed by the system 100 to heat the water.10070] The controller 106 may select the most efficient operational state for the system 200 / heat pump assembly 104 given the same water delivery capacity, and cause the system 200 / heat pump assembly 104 to operate in the selected operational state (e.g., in the single passCOE-051-WO (92575-3143) mode, in the multi pass mode, or in the multi pass mode in combination with the usage of the secondary heating source 302).

[0071] FIG. 4 depicts a block diagram of an exemplary third water heating system 400 (or system 400) in accordance with one or more embodiments of the present disclosure. The system 400 may be similar to the system 100 and may include similar or the same components as the system 100. In the system 400, in addition to determining an optimal operational state / mode of the heat pump assembly 104 and causing the heat pump assembly 104 to operate in the determined operational state / mode (as described above in conjunction with FIG. 1), the controller 106 may further estimate a predicted demand of hot water (or “future hot water demand”) from the system 400 at a future time. In some aspects, the controller 106 may estimate the future hot water demand based on a historical hot water demand pattern (information of which may be stored in the controller memory). For example, the controller 106 may estimate that the user may require 40 gallons or 70 gallons of hot water at 7 AM, e.g., if the system 100 is installed at a hotel and the hotel occupants generally require greater amounts of hot water in the morning.

[0072] In some aspects, the future hot water demand may be indicative of a predicted amount of hot water (e.g., 40 gallons) that the user may require at a future time (e.g., at 7 AM). The future hot water demand may be considered as one of the parameters described above, based on which the controller 106 determines the optimal operational state / mode of the heat pump assembly 104.

[0073] Responsive to determining the future hot water demand, the controller 106 may determine other parameters associated with the system 400 and / or ambient conditions. For example, responsive to determining the future hot water demand, the controller 106 may determine a current ambient temperature and humidity level, the inlet water temperature, a current time, an amount of hot water at the set point temperature already stored in the storage tank 102 (if some amount of such hot water is already available), and / or the like. The controller 106 may then correlate these parameters to determine the optimal operational state / mode of the heat pump assembly 104 such that the system 400 meets the future hot water demand in the most efficient manner, as described above.COE-051-WO (92575-3143)

[0074] In addition, in this case, the controller 106 may determine an optimal height to inject hot water 402 (that the heat pump assembly 104 provides) into the storage tank 102 based on the future hot water demand, and one or more other parameters such as a time duration between a current time and the future time (i.e., the time remaining to heat the water in the storage tank 102) and the amount of hot water at the set point temperature already stored in the storage tank 102 (if any). In some aspects, the controller 106 may determine the optimal height so that when the future time arrives (i.e., by 7 AM), the storage tank’s top portion may store the required amount of hot water (i.e., 40 gallons or 75 gallons) and the future hot water demand may be met. Responsive to determining the optimal height (and the optimal operational state / mode, as described above), the controller 106 may cause the heat pump assembly 104 to operate at the optimal operational state / mode and inject the hot water 402 into the storage tank 102 at the determined optimal height.10075] For example, if the controller 106 determines the optimal operational state as the single pass mode and the optimal height to be “Pl” below the storage tank’s top end (as shown in FIG. 4), the controller 106 may cause the heat pump assembly 104 to operate in the single pass mode and inject the hot water 402 via a tank inlet port 404 that is disposed on the storage tank 102 “Pl” distance below the storage tank’s top end. In this case, the volume of the storage tank 102 between the tank inlet port 404 and the storage tank’s top end may constitute 40 gallons, and hence when the future time arrives (i.e., by 7 AM), the volume of the storage tank 102 between the tank inlet port 404 and the storage tank’s top end may have stored 40 gallons of hot water at the set-point temperature. In this manner, the controller 106 may ensure that the user receives the required amount of hot water by 7 AM and does not have to wait for the system 400 to heat the water.

[0076] As another example, if the controller 106 determines the optimal operational state as the single pass mode and the optimal height to be “P2” below the storage tank’s top end (as shown in FIG. 4), the controller 106 may cause the heat pump assembly 104 to operate in the single pass mode and inject the hot water 402 via a tank inlet port 406 that is disposed on the storage tank 102 “P2” distance below the storage tank’s top end. In this case, the volume of the storage tank 102 between the tank inlet port 404 and the storage tank’s top end may constituteCOE-051-WO (92575-3143) the volume of hot water that the user may require at the future time (e.g., 75 gallons), and hence when the future time arrives (i.e., by 7 AM), the volume of the storage tank 102 between the tank inlet port 406 and the storage tank’s top end may have stored 75 gallons of hot water at the set-point temperature.

[0077] It may be appreciated that in the system 400, the controller 106 may cause the heat pump assembly 104 to inject the hot water 402 at locations that may be below the storage tank’s top portion even when the heat pump assembly 104 is operating in the single pass mode, so that the user’s future hot water demand may be efficiently met. The system 400 provides the flexibility to inject the hot water 402 at different locations / heights in the storage tank 102 irrespective of the operational state / mode of the heat pump assembly 104, so that the user receives the required amount of hot water without having to wait for the system 400 to heat the water.

[0078] Although the examples described above describe scenarios where the controller 106 determines the optimal operational state / mode as the single pass mode, the described examples should not be construed as limiting. The controller 106 may similarly cause the heat pump assembly 104 to inject the hot water 402 at different heights in the storage tank 102 when the heat pump assembly 104 operates in the multi pass mode, based on the amount of hot water that the user may require at the future time and the time difference between the current time and the future time. For example, if the time difference is small, the controller 106 may cause the heat pump assembly 104 to operate in the single pass mode; and if the time difference is large, the controller 106 may cause the heat pump assembly 104 to operate in the multi pass mode (to enhance the system efficiency, as described above).

[0079] In the exemplary embodiment depicted in FIG. 4, the storage tank 102 is shown to include a plurality of tank inlet ports (e.g., the tank inlet ports 404, 406) that may be disposed along the length of the storage tank 102 at different heights. The tank inlet ports may be configured to receive the hot water 402 from the valve unit 118 and inject the received hot water 402 at different locations / heights in the storage tank 102 as described above. In this case, the valve unit 118 may enable the flow of hot water 402 from the heat pump assembly 104 to an appropriate tank inlet port, based on the command signals received from theCOE-051-WO (92575-3143) controller 106. For example, if the controller 106 determines that the optimal height to inject the hot water 402 into the storage tank 102 is “Pl”, the controller 106 may transmit a command signal to the valve unit 118 to cause the valve unit 118 to enable the flow of hot water 402 from the heat pump assembly 104 to the tank inlet port 404.

[0080] Although the description above describes an aspect where the storage tank 102 includes the plurality of tank inlet ports at different heights and the valve unit 118 enables the flow of hot water 402 into an appropriate tank inlet port, the present disclosure is not limited to such an aspect / arrangement. In alternative aspects, the water heating system may include other means to inject the hot water 402 at different heights / locations in the storage tank 102, as described below in conjunction with FIG. 5.[00811 FIG. 5 depicts a block diagram of an exemplary fourth water heating system 500 (or system 500) in accordance with one or more embodiments of the present disclosure. The system 500 may be similar to the system 400; however, the system 500 may not include the plurality of tank input ports. Instead, the system 500 may include an adjustable water inlet unit 502 (or unit 502) that may be disposed in proximity to the storage tank’s top portion or middle portion (or any portion in between). The unit 502 may receive the hot water 402 from the heat pump assembly 104 and inject the hot water 402 at different locations / heights within the storage tank 102 based on an operational state of the unit 502.

[0082] In this case, the system 500 may not include the valve unit 118, and the unit 502 may directly receive the hot water 402 from the recirculation pump unit 116. In the system 500, the controller 106 may adjust an operation or operational state of the unit 502 based on the determined optimal height, to cause the heat pump assembly 104 to inject the hot water 402 at the optimal height into the storage tank 102.[0083| In one exemplary aspect, the unit 502 may be in the form of an adjustable dip tube (not shown) or an adjustable water output tube that may move up or down along the length / height of the storage tank 102 based on the command signals received from the controller 106. In this case, the controller 106 may cause the adjustable dip tube to move up towards the storage tank’s top portion when the controller 106 determines the optimal height to be closer to the storage tank’s top portion. Similarly, the controller 106 may cause the adjustable dip tubeCOE-051-WO (92575-3143) to move down towards the storage tank’s middle portion when the controller 106 determines the optimal height to be closer to the storage tank’s middle portion.

[0084] In another exemplary aspect, the unit 502 may be in the form of a J-shaped tube, as shown in a view 504. In this case, the controller 106 may cause rotation of the J-shaped tube based on the determined optimal height at which the hot water 402 should be injected into the storage tank 102. In yet another exemplary aspect, the unit 502 may be in the form of concentric hollow tubes with slits of predefined designs / patterns, as shown in a view 506. In this case, the controller 106 may cause one tube to rotate relative to the other, to cause overlapping of the slit patterns at different heights, and hence to cause the hot water 402 to be injected into the storage tank 102 at different heights. Details of the tubes depicted in the views 504 and 506, and other similar tubes that may be used to inject the hot water 402 into the storage tank 102 at different heights, are described in the US patent application No.63 / 683,529, filed August 15, 2024, which is incorporated by reference in its entirety in the present disclosure.

[0085] In this manner, the controller 106 of the systems 400, 500 not only causes the heat pump assembly 104 to operate in the optimal operational state / mode (e.g., the single pass mode or the multi pass mode) to enhance the system efficiency, but also causes the heat pump assembly 104 to inject the hot water at the optimal height in the storage tank 102 so that the user may receive the required amount of hot water without having to wait.

[0086] FIG. 6 depicts a block diagram of the controller 106 in accordance with one or more embodiments of the present disclosure. The controller 106 may include a plurality of components including, but not limited to, a processor 605, a memory 610, and a communication interface 615. The controller 106 may be a computing device configured to receive data, determine actions based on the received data (e.g., the inputs obtained from the sensor unit 108) and output a control signal instructing one or more system components to perform one or more actions.

[0087] In some aspects, the controller 106 may be configured to send and receive wireless or wired signals, and the signals may be analog or digital signals. The wireless signals may include Bluetooth, BLE, WiFi, ZigBee, infrared, microwave radio, or any other type ofCOE-051-WO (92575-3143) wireless communication signals as may be suitable for a particular system application. The hard-wired signals can include communication signals between any directly wired connections between the controller 106 and other system components. For example, the controller 106 can have a hard-wired 24 Volts Direct Current (VDC) connection to the sensors included in the sensor unit 108 described above.[0088 j Alternatively, the controller 106 may communicate with the sensors via a digital connection. The digital connection can include a connection such as an Ethernet or a serial connection and can utilize any suitable communication protocol for the system application, such as Modbus, fieldbus, PROFIBUS, SafetyBus, Ethemet / IP, and / or the like. Furthermore, the controller 106 can utilize a combination of wireless, hard-wired, and analog or digital communication signals to communicate with and control the various system components. A person ordinarily skilled in the art may appreciate that the above configurations are given merely as non-limiting examples, and the actual configuration can vary depending on the particular system application.

[0089] The memory 610 may be configured to store a program and / or instructions associated with the functions and methods described herein. The processor 605 may be configured to execute the program and / or instructions stored in the memory 610. The memory 610 can include one or more suitable types of memory (e.g., volatile or non-volatile memory, random access memory (RAM), read only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disks, optical disks, floppy disks, hard disks, removable cartridges, flash memory, a redundant array of independent disks (RAID), and the like) for storing files including the operating system, application programs (including, for example, a web browser application, a widget or gadget engine, and or other applications, as necessary), executable instructions and data. One, some, or all of the processing techniques or methods described herein can be implemented as a combination of executable instructions and data within the memory 610.

[0090] The communication interface 615 may be configured to send or receive communication signals between the various system components. The communication interfaceCOE-051-WO (92575-3143)615 can include hardware, firmware, and / or software that allows the processor 605 to communicate with the other components via wired or wireless networks, whether local or wide area, private or public, as known in the art. The communication interface 615 can also provide access to a cellular network, the Internet, a local area network, or another wide-area network as suitable for the particular system application.[00 11 Additionally, the controller 106 may have or be in communication with a user interface (not shown) for receiving inputs from a system user. The user interface may be installed locally on the system 100.

[0092] The function of the controller 106 is already described above in conjunction with FIGS. 1-5, and hence is not described again here for the sake of simplicity and conciseness.

[0093] FIG. 7 depicts a flow diagram of an exemplary method 700 to switch an operational state of a water heating system in accordance with one or more embodiments of the present disclosure. FIG. 7 may be described with continued reference to prior figures. The following process is exemplary and not confined to the steps described hereafter. Moreover, alternative embodiments may include more or less steps than are shown or described herein and may include these steps in a different order than the order described in the following example embodiments.( 0094] The method 700 may start at step 702. At step 704, the method 700 may include estimating, by the controller 106, a predicted demand of hot water from the system 400 at a future time based on a historical hot water demand pattern. At step 706, the method 700 may include switching, by the controller 106, an operational state / mode of the heat pump assembly 104 between the single pass mode and the multi pass mode based on the predicted demand.

[0095] At step 708, the method 700 may include determining, by the controller 106, an optimal height to inject the hot water into the storage tank 102 based on the predicted demand and a time duration between a current time and the future time. At step 710, the method 700 may include causing, by the controller 106, the heat pump assembly 104 to inject the hot water at the optimal height into the storage tank 102.

[0096] The method 700 may stop at step 712.COE-051-WO (92575-3143)

[0097] In the above disclosure, reference has been made to the accompanying drawings, which form a part hereof, which illustrate specific implementations in which the present disclosure may be practiced. It is understood that other implementations may be utilized, and structural changes may be made without departing from the scope of the present disclosure. References in the specification to “one embodiment,” “an embodiment,” “an example embodiment,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a feature, structure, or characteristic is described in connection with an embodiment, one skilled in the art will recognize such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0098] It should also be understood that the word “example” as used herein is intended to be non-exclusionary and non-limiting in nature. More particularly, the word “example” as used herein indicates one among several examples, and it should be understood that no undue emphasis or preference is being directed to the particular example being described.[0099| With regard to the processes, systems, methods, heuristics, etc. described herein, it should be understood that, although the steps of such processes, etc. have been described as occurring according to a certain ordered sequence, such processes could be practiced with the described steps performed in an order other than the order described herein. It further should be understood that certain steps could be performed simultaneously, that other steps could be added, or that certain steps described herein could be omitted. In other words, the descriptions of processes herein are provided for the purpose of illustrating various embodiments and should in no way be construed so as to limit the claims.

[0100] Accordingly, it is to be understood that the above description is intended to be illustrative and not restrictive. Many embodiments and applications other than the examples provided would be apparent upon reading the above description. The scope should be determined, not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. It is anticipated and intended that future developments will occur in theCOE-051-WO (92575-3143) technologies discussed herein, and that the disclosed systems and methods will be incorporated into such future embodiments. In sum, it should be understood that the application is capable of modification and variation.|0101] All terms used in the claims are intended to be given their ordinary meanings as understood by those knowledgeable in the technologies described herein unless an explicit indication to the contrary is made herein. In particular, use of the singular articles such as “a,” “the,” “said,” etc., should be read to recite one or more of the indicated elements unless a claim recites an explicit limitation to the contrary. Conditional language, such as, among others, “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments could include, while other embodiments may not include, certain features, elements, and / or steps. Thus, such conditional language is not generally intended to imply that features, elements, and / or steps are in any way required for one or more embodiments.

Claims

COE-051-WO (92575-3143)CLAIMSTHAT WHICH IS CLAIMED IS:

1. A water heating system comprising: a storage tank; a heat pump assembly configured to provide hot water to the storage tank, wherein the heat pump assembly is configured to operate in a single pass mode and a multi pass mode; and a controller configured to switch an operational state of the heat pump assembly between the single pass mode and the multi pass mode based on one or more parameters.

2. The water heating system of claim 1, wherein the heat pump assembly is configured to receive water from the storage tank and heat the received water.

3. The water heating system of claim 2, wherein the heat pump assembly is configured to heat the received water to a set-point temperature and provide the hot water at the set-point temperature to the storage tank when the heat pump assembly operates in the single pass mode.

4. The water heating system of claim 2, wherein the heat pump assembly is configured to incrementally heat the received water and recirculate an incrementally heated water between the heat pump assembly and the storage tank when the heat pump assembly operates in the multi pass mode.

5. The water heating system of claim 1, wherein the heat pump assembly is configured to provide the hot water to a top portion of the storage tank when the heat pump assembly operates in the single pass mode.

6. The water heating system of claim 5, wherein the heat pump assembly is configured to provide the hot water to a middle portion of the storage tank when the heat pump assembly operates in the multi pass mode, wherein the middle portion is between the top portion and a bottom portion of the storage tank.COE-051-WO (92575-3143)7. The water heating system of claim 6 further comprising a recirculation pump unit configured to control a flow of hot water from the heat pump assembly to the top portion of the storage tank and the middle portion of the storage tank, wherein the controller causes the recirculation pump unit to enable a flow of the hot water to the top portion of the storage tank when the heat pump assembly operates in the single pass mode, and wherein the controller causes the recirculation pump unit to enable the flow of the hot water to the middle portion of the storage tank when the heat pump assembly operates in the multi pass mode.

8. The water heating system of claim 6 further comprising a valve unit configured to control a flow of hot water from the heat pump assembly to the top portion of the storage tank and the middle portion of the storage tank, wherein the controller causes the valve unit to enable a flow of the hot water to the top portion of the storage tank when the heat pump assembly operates in the single pass mode, and wherein the controller causes the valve unit to enable the flow of the hot water to the middle portion of the storage tank when the heat pump assembly operates in the multi pass mode.

9. The water heating system of claim 1, wherein the heat pump assembly comprises a variable speed compressor, and wherein the controller is configured to switch the operational state of the heat pump assembly between the single pass mode and the multi pass mode by causing an adjustment of a speed of the variable speed compressor.

10. The water heating system of claim 1, wherein the one or more parameters comprise at least one of a hot water demand, ambient conditions, an inlet water temperature, a water flow rate, or a user input.COE-051-WO (92575-3143)11. The water heating system of claim 1, further comprising a secondary heating source configured to heat water, wherein the controller is further configured to cause the secondary heating source to provide the hot water to the storage tank based on the one or more parameters.

12. The water heating system of claim 11, wherein the controller causes the secondary heating source to provide the hot water to the storage tank when the heat pump assembly operates in the multi pass mode.

13. The water heating system of claim 11, wherein the secondary heating source is one of a solar heating unit, a gas heating unit or an electric heating unit.

14. The water heating system of claim 1, wherein the controller is further configured to estimate a predicted demand of hot water at a future time, wherein the predicted demand is indicative of a predicted amount of hot water that is required at the future time, and wherein the one or more parameters comprise the predicted demand.

15. The water heating system of claim 14, wherein the controller is further configured to: determine an optimal height to inject the hot water into the storage tank based on the predicted demand and a time duration between a current time and the future time; and cause the heat pump assembly to inject the hot water at the optimal height into the storage tank.

16. The water heating system of claim 15, further comprising an adjustable water inlet unit configured to inject the hot water into the storage tank at different heights, wherein the controller adjusts an operation of the adjustable water inlet unit to cause the heat pump assembly to inject the hot water at the optimal height into the storage tank.COE-051-WO (92575-3143)17. The water heating system of claim 14, wherein the controller estimates the predicted demand based on a historical hot water demand pattern.

18. A water heating system comprising: a storage tank; a heat pump assembly configured to provide hot water to the storage tank, wherein the heat pump assembly is configured to operate in a single pass mode and a multi pass mode; and a controller configured to: switch an operational state of the heat pump assembly between the single pass mode and the multi pass mode based on one or more parameters; and enable a secondary heating source to provide additional hot water to the storage tank when the heat pump assembly operates in the multi pass mode based on the one or more parameters.

19. The water heating system of claim 18, wherein the secondary heating source is one of a solar heating unit, a gas heating unit or an electric heating unit.

20. A method comprising: estimating, by a controller, a predicted demand of hot water from a water heating system at a future time based on a historical hot water demand pattern; switching, by the controller, an operational state of a heat pump assembly between a single pass mode and a multi pass mode based on the predicted demand, wherein the heat pump assembly is configured to provide hot water to a storage tank and configured to operate in the single pass mode and the multi pass mode; determining, by the controller, an optimal height to inject the hot water into the storage tank based on the predicted demand and a time duration between a current time and the future time; and causing, by the controller, the heat pump assembly to inject the hot water at the optimal height into the storage tank.

Images