US20240240828A1

US20240240828A1 - Systems and Methods for Heating Water Using Heat Pump Water Heaters Having Natural Convection Evaporator Heat Exchangers

Info

Publication number: US20240240828A1
Application number: US18/413,396
Authority: US
Inventors: Govinda Mahajan; Vishwanath Reddy Ardha; Atilhan Manay
Original assignee: Rheem Manufacturing Co
Current assignee: Rheem Manufacturing Co
Filing date: 2024-01-16
Publication date: 2024-07-18

Abstract

A heat pump water heater is disclosed herein. The heat pump water heater includes an outer casing and a water tank disposed within the outer casing. The water tank includes a top wall, a bottom wall, and a side wall extending between and connected to the bottom wall and the top wall and has a hot water outlet and a cold water inlet configured to enable water to flow into and out of the water tank. Additionally, the water heater includes a condenser heat exchanger surrounding at least a portion of the side wall, an insulation jacket disposed around at least the side wall and the bottom wall of the water tank and the condenser heat exchanger, a natural convection evaporator disposed about the side wall and employing no fan to direct heating medium to the refrigerant, and a compressor and tubing connected to the condenser heat exchanger and the natural convection evaporator.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to and the benefit of U.S. provisional patent No. 63/480,213, filed Jan. 17, 2023, which is hereby incorporated by reference herein in its entirety.

FIELD

The present disclosure relates to water heaters and more particularly to heat pump water heaters that use natural convection evaporator heat exchangers and do not include air movement devices, such as fans.

BACKGROUND

The coefficient of performance of heat pump water heaters is considerably better than the coefficient of performance of conventional electric water heaters, making heat pump water heaters more energy efficient. However, conventional electric heaters may produce less noise and/or may occupy less space or have smaller dimensions impeding replacement with a more energy efficient heat pump water heater. Therefore, there is a need for heat pump water heaters that solves the noise issues and problematic size requirement of conventional heat pump water heaters.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description is set forth with reference to the accompanying drawings. In some instances, the use of the same reference numerals may indicate similar or identical items. Various 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. Throughout this disclosure, depending on the context, singular and plural terminology may be used interchangeably.

FIG. 1 is a schematic diagram illustrating a heat pump water heater in accordance with one or more embodiments of the disclosure.

FIG. 2 is a schematic diagram illustrating a heat pump water heater in accordance with one or more embodiments of the disclosure.

FIG. 3 is a schematic diagram illustrating a heat pump water heater in accordance with one or more embodiments of the disclosure.

FIG. 4 is a flow diagram depicting an illustrative method for heating water in accordance with one or more embodiments of the disclosure.

DETAILED DESCRIPTION

The present disclosure is directed to heat pump water heaters. Heat pump water heaters may be used in residential, commercial, or industrial property for hot water production and storage supporting various consumer and commercial applications. A water heater using a heat pump works on a reverse refrigeration cycle, absorbing and using heat from the surrounding air to heat water within a water tank. A conventional heat pump water heater includes a water tank, fan, compressor, condenser heat exchanger, and an evaporator heat exchanger. The arrangement to incorporate the components of a conventional heat pump water heater may make them incompatible to fit a typical installation location of less energy efficient conventional electric water heaters. For example, the reliance of conventional heat pump water heaters on an air source (e.g., a fan or a blower) to draw air across the evaporator heat exchanger, increases the unit size requirement, price point, and noise level, which may limit the applications of conventional heat pump water heaters relative to conventional electric water heaters. More so, the air source and compressor of conventional heat pump water heaters may collectively increase the unit noise level, which may be undesirable in certain applications.
There is therefore a need for improved heat pump water heaters that are not too large (e.g., tall) to replace conventional electric water heaters and that have reduced operational noise relative to conventional heat pump water heaters.
The heat pump water heater disclosed herein may include a heat pump forming a vapor-compression cycle system, which may include a refrigerant line, which conducts refrigerant through a refrigerant path that encompasses a condenser heat exchanger, an expansion valve, an evaporator heat exchanger, and a compressor. In certain embodiments, the heat pump water heater disclosed herein may rely on a natural convection evaporator to transfer heat to the refrigerant. Natural convection is a mechanism of heat transportation in which the fluid motion is not generated by an external source. Instead, the fluid motion is caused by buoyancy, the difference in fluid density occurring due to temperature gradients. In this manner, when the refrigerant passes through the coils of the natural convection evaporator heat exchanger, the temperature difference between the ambient air of the water heater location and the refrigerant is used as a basis for warmer air to heat the refrigerant without the need for an air movement source (e.g., a fan or blower) directing air to the coils of the evaporator heat exchanger. As a result, the ambient air surrounding the natural convection heat exchanger may rise along the natural convection heat exchanger and exchange heat with the refrigerant therein.
By using a natural convection evaporator heat exchanger employing no air movement source, the heat pump water heater may reduce the unit size and eliminate a source of noise that has typically limited the application of conventional heat pump water heaters. For example, the unit size may be reduced by 1 to 30 inches in height (e.g., a reduction of 15 inches may be possible in certain embodiments). The noise of the unit may be reduced by 1 dBa to 60 dBa (e.g., a reduction in noise from 65 dBa to 42 dBa may be possible in certain embodiments).
In certain embodiments, the heat pump water heater may include a water tank. The water tank may include a bottom wall, a top wall, and a side wall extending between and connected to the bottom wall and the top wall. That is, the bottom wall, the top wall, and the side wall may collective form the water tank. In some instances, the water tank may be cylindrical. In other instances, the water tank may form a box like structure. The water tank may be any suitable size, shape, or configuration.
The heat pump water heater may also include a condenser heat exchanger, which may be disposed about at least a portion of the side wall of the water tank. In other instances, the condenser heat exchanger may be disposed about at least a portion of the side wall and/or at least a portion of the bottom wall and/or top wall of the water tank. Any suitable condenser heat exchanger may be used herein. The condenser heat exchanger may include a condenser coil or the like. For example, the condenser heat exchanger may include a double tube heat exchanger, a shell and tube heat exchanger, a tube in tube heat exchanger, a plate heat exchanger, or the like. In other instances, the condenser heat exchanger may be at least one of a coil-wrapped type heat exchanger, a roll-bonded type heat exchanger, and/or a micro-channel type heat exchanger. The condenser heat exchanger may be any suitable size, shape, or configuration.
The heat pump water heater may include an insulation jacket. In some instances, the insulation jacket may be disposed about at least the side wall of the water tank and the condenser heat exchanger. That is, the insulation jacket may surround at least a portion of the water tank and the condenser heat exchanger. In some instances, the insulation jacket may completely surround the water tank, including the side wall, the bottom wall, and the top wall of the water tank. In other instances, the insulation jacket may partially surround the water tank, including a portion or none of the side wall, the bottom wall, and/or the top wall of the water tank.
In certain embodiments, the insulation jacket may include an outer casing and an insulation material disposed between the outer casing and at least a portion of the side wall, the bottom wall, and/or the top wall of the water tank. Any suitable outer casing and insulation material may be used herein. In some instances, the insulation material may be omitted. In such instances, the space between the outer casing of the insulation jacket and at least a portion of the side wall, the bottom wall, and/or the top wall of the water tank may be air. The insulation jacket may be any suitable size, shape, or configuration.
The heat pump water heater may include a natural convection evaporator heat exchanger disposed about the insulation jacket. In some instances, the natural convection evaporator heat exchanger may be disposed within the insulation jacket. For example, the natural convection evaporator heat exchanger may be disposed between the outer casing of the insulation jacket and at least a portion of the side wall, the bottom wall, and/or the top wall of the water tank. In some instances, the natural convection evaporator heat exchanger may be disposed on or about an inner wall of the outer casing. In other instances, the natural convection evaporator heat exchanger may be disposed on or about an exterior surface of the outer casing of the insulation jacket. The natural convection evaporator heat exchanger may be disposed at any suitable location about the insulation jacket.
Any suitable natural convection evaporator heat exchanger may be used herein. The natural convection evaporator heat exchanger may include an evaporator coil or the like. For example, the natural convection evaporator heat exchanger may include a double tube heat exchanger, a shell and tube heat exchanger, a tube in tube heat exchanger, a plate heat exchanger, or the like. In other instances, the natural convection evaporator heat exchanger may be at least one of a coil-wrapped type heat exchanger, a roll-bonded type heat exchanger, and/or a micro-channel type heat exchanger. The natural convection evaporator heat exchanger may be any suitable size, shape, or configuration.
As noted above, the evaporator may be a micro-channel type heat exchanger. In certain embodiments, because the natural convection evaporator does not employ an air source to direct air to the evaporator coils, the natural convection evaporator may utilize an increased surface area as compared to traditional evaporator coils (e.g., up to 20 times or more surface area in some instance) to increase water heating capacity/efficiency of the system. To increase the surface area of the natural convection evaporator, a natural convection microchannel evaporator may be implemented herein. For example, the natural convection microchannel evaporator may include a plurality of microchannels that are grouped together in bands. In some instances, the hydraulic diameter of the channels may be less than 1 mm. The microchannels may be any suitable size, shape, or configuration. For example, the microchannels may be cuboidal tubes, and the width of each cuboidal tube may be in a range of about 1 mm to 32 mm. The microchannels may be any suitable dimensions. A count of microchannels in the plurality of microchannels may depend on the dimensions and usage requirements of the water heater. As would be appreciated, increasing the count of microchannels may increase the available surface area on the natural convection evaporator for heat transfer, thereby increasing water heating capacity/efficiency of the system and reducing heating times/cycles.
The heat pump water heater may include a compressor fluidly connected to the condenser heat exchanger and the natural convection evaporator heat exchanger. The compressor may act as a pump to provide pressure to the refrigerant flowing through the refrigerant line to thereby maintain the refrigerant flowing through the closed loop that the refrigerant line defines. The compressor may pump a gaseous refrigerant received from the natural convection evaporator heat exchanger forward, increasing the pressure and temperature of the refrigerant and causing the now hotter refrigerant gas to flow through the condenser heat exchanger. The hot refrigerant may be separated from water within the water tank by the refrigerant line wall and the wall of the water tank, both of which may be metallic and therefore relatively heat conductive. Thus, as the refrigerant travels through the length of the condenser heat exchanger, the refrigerant may transfer heat through the walls to the cooler water within the water tank. Any suitable heat exchanger configuration between the condenser heat exchanger and the water tank may be used herein.
In certain embodiments, the compressor may be at least one of a reciprocating compressor or a scroll compressor. Any suitable compressor may be used herein. In some instances, the compressor may be located outside the outer casing of the insulation jacket. In other instances, the compressor may be located inside the outer casing of the insulation jacket. In some instances, the capacity of the compressor may be reduced as compared to typical compressors of similar sized systems with forced air (e.g., fans) evaporator systems, which may result in reduced surface area requirements for the natural convection evaporator. This, however, may result in increased heating times/cycles. The below chart provides non-limiting examples of compressor capacity, heat transfer area, heat transfer coefficient, fan CFM, heat transfer type, and evaporate tube size. For example, the below chart illustrates that if the same ⅜ inch tube and natural convection is used, the heat transfer area may be around 17 times more. But when the compressor size is reduced in conjunction with a microchannel evaporator, the heat transfer area is only three times more than the current heat exchanger, which is possible, as the tank surface is approximately six times the evaporator area.


Compressor	Compressor	Heat	Heat Transfer
Capacity	Capacity	Transfer	Coefficient	Fan	Heat
(Btu/hr)	(W)	Area (m2)	Air(W/m2K)	CFM	Transfer	Evaporator

3308	968	6.438	104	200	Forced	3/8th Smooth
					Convection	Tube
3308	968	107.9922581	6.2	0	Natural	3/8th Smooth
					Convection	Tube
3307	968	53.99612903	6.2	0	Natural	Microchannel
					Convection
1000	3417	17.99870968	6.2	0	Natural	Microchannel
					Convection

The heat pump water heater may include a condensate collector tray. In certain embodiments, the condensate collector tray may be located below the bottom wall of the water tank for collecting moisture that may form on or about the natural convection evaporator heat exchanger and drip there off. The condensate collector tray may be located below the bottom wall of the water tank for the purpose of draining condensation outside and away from the heat pump water heater.
As refrigerant flows through the condenser heat exchanger, it may change phase from gas to liquid. Still under the pressure provided by the compressor, however, the now liquid refrigerant may flow from the condenser heat exchanger to the expansion valve, which may drop the pressure of the liquid refrigerant as it enters the natural convection evaporator heat exchanger. In certain embodiments, as the natural convection evaporator absorbs heat energy from the surrounding air, the coils of the natural convection evaporator heat exchanger may remove condensation from the air leading to moisture formation. By disposing the natural convection evaporator within the insulation jacket, inside the outer casing of the insulation jacket, the condensate collector tray is able to collect the moisture drips that may form on or about the coils of the natural convection evaporator heat exchanger.
In some embodiments, the natural convection evaporator heat exchanger is disposed on an exterior surface of the insulation jacket. That is, the natural convection evaporator heat exchanger may be disposed on an exterior of the water heater. Separating the natural convection evaporator heat exchanger from the insulation jacket can improve the amount of airflow across the natural convection evaporator heat exchanger without the need to employ an air source. For example, airflow across the natural convection evaporator heat exchanger may be greater when the natural convection heat exchanger is located on an exterior of the water heater due to the increase in air volume within the environment (e.g., utility room or the like) that the water heater is located as compared to the air volume within the insulation jacket, particularly if the insulation jacket includes an insulation material therein. Locating the natural convection heat exchanger on an exterior of the water heater may result in increased heat transfer between the air in the environment and the refrigerant within the natural convection evaporator heat exchanger. More so, disposing the natural convection evaporator heat exchanger outside the outer casing of the insulation jacket may improve the accessibility of the coils of the natural convection evaporator heat exchanger, which may improve cleaning accessibility. For example, dust and dirt accumulating on the coils of natural convection evaporator heat exchanger can lead to ice buildup on the coils of natural convection evaporator heat exchanger, leading to frost formation, which is undesirable. The frost build-up on the coils of the natural convection evaporator heat exchanger can reduce the amount of airflow across the coils of the natural convection evaporator heat exchanger and thus prevent the refrigerant from experiencing the proper heat loading.
In certain embodiments, the compressor may be located outside the outer casing of the insulation jacket. In other embodiments, the compressor may be located inside the outer casing of the insulation jacket. In some instances, the insulation jacket may include an internal wall, which separates the bottom wall of the water tank from the compressor located within the outer casing of the insulation jacket. Whether the compressor is located outside of the outer casing of the insulation jacket or inside of the outer casing of the insulation jacket, the compressor may also be located within a compressor jacket in order to reduce noise. For example, during operation of the heat pump cycle, the compressor can be a source of heat pump water heater noise and vibration. In particular, the compressor can generate noise during the process of pumping refrigerant or when the water heater unit is powering down as the refrigerant pressures equalize. By disposing the compressor inside the outer casing of the insulation jacket and including an internal wall of the insulation jacket that separates the compressor from the water tank (and optionally locating the compressor within a compressor jacket), the heat pump water heater may reduce a main source of noise throughout the unit operation.
Modifications and variations of the devices and methods described herein will be obvious to those skilled in the art from the foregoing detailed description. Such modifications and variations are intended to come within the scope of the appended claims.
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 heat pump water heaters that use natural convection evaporator heat exchangers and do not include air movement devices, such as fans. The present disclosure, however, is not so limited, and can be applicable in other contexts, including any suitable systems (including units, devices, apparatuses, etc.). residential, commercial, or industrial water heater systems (such tank systems or tankless systems), industrial water heaters, and other systems that include a natural convection evaporator for various purposes. More so, the present disclosure, for example and not limitation, can be applied to other residential, commercial, or industrial air conditioning systems that include a natural convection evaporator. 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 heating water, it will be understood that other implementations can take the place of those referred to.
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 system and method 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.
Turning now to the drawing, FIG. 1 is a schematic diagram illustrating a heat pump water heater 100 of one embodiment of the present disclosure. The heat pump water heater 100 is used to heat water. The heat pump water heater 100 may include a water inlet 120 and a water outlet 122 in communication with a water tank 114. The water tank 114 may be configured to store a volume of heated water therein. The water tank 114 may be any suitable size, shape, or configuration. The water inlet 120 may be configured to introduce water to the water tank 114. In some instances, the water from the water inlet 120 may be provided by a utility or the like. The water outlet 122 may be configured to provide heated water from the water tank 114.
In order to produce heated water, the heat pump water heater 100 may include a condenser heat exchanger 102, a refrigerant line 103, a natural convection evaporator heat exchanger 104, a compressor 110, and an expansion valve 124, which collectively form a vapor-compression cycle system. The heat pump water heater 100 may include additional components.
The refrigerant line 103 may be a closed loop having a refrigerant therein. As the refrigerant circulates through the closed loop of the vapor-compression cycle system, the refrigerant is alternately compressed and expanded, changing the state of the refrigerant from a liquid to a vapor. As the refrigerant changes state, heat is absorbed and expelled by the vapor-compression cycle system. For example, during operation of the heat pump water heater 100, a refrigerant within the refrigerant line 103 may exit the natural convection evaporator heat exchanger 104 as a fluid in the form of a superheated vapor and/or high-quality vapor mixture.
Upon exiting the natural convection evaporator heat exchanger 104, the refrigerant may enter the compressor 110, where the pressure and temperature may increase. For example, the compressor 110 may pump and compress the refrigerant to increase the pressure and temperature of the refrigerant. In some instances, the compressor 110 may be a rotary compressor, a reciprocating compressor, a scroll compressor, or the like. Any suitable compressor may be used herein. In this manner, the temperature and pressure of the refrigerant may be increased in the compressor 110 such that the refrigerant becomes a superheated vapor.
The superheated vapor from the compressor 110 may enter the condenser heat exchanger 102. In some instances, the condenser heat exchanger 102 may include a coil or the like wrapped around the water tank 114. In this manner, while in the condenser heat exchanger 102, the superheated vapor may transfer energy to the water within the water tank 114. For example, the hot refrigerant may be separated from water within the water tank 114 by the wall of the of the coils of the condenser heat exchanger 102 and the wall of the water tank 114, both of which may be metallic and therefore relatively heat conductive. Thus, as the refrigerant travels through the length of the coil of the condenser heat exchanger 102, the refrigerant may transfer heat through the walls to the cooler water within the water tank 114.
Upon transferring energy to the water within the water tank 114, the refrigerant may turn into a saturated liquid and/or high-quality vapor mixture. This high-quality/saturated liquid vapor mixture may exit the condenser heat exchanger 102 and travel through the expansion valve 124. The refrigerant may be expanded by the expansion valve 124. As a result, the refrigerant may undergo the expansion process in the expansion valve 124 to become a low pressure, low temperature fluid. Upon exiting the expansion valve 124, the pressure and temperature of the refrigerant may drop, at which time the refrigerant may enter the natural convection evaporator 104 and the cycle repeats itself.
The heat pump water heater 100 may include the hot water outlet 122 and the cold water inlet 120, respectively configured to enable water to flow into and out of the water tank 114. In some instance, the water tank 114 may be disposed within an outer casing 108. The cold water inlet 120 may be placed near the bottom of the water tank 114, and the hot water outlet 122 may be placed near the top of the water tank 114. The condenser heat exchanger 102 may surround at least a portion of the water tank 114 side wall 115, establishing a heat exchange relationship with the water in the water tank 114. For example, the condenser heat exchanger 102 may include a number of coils wrapped around the side wall 115 of the water tank 114. The coils of the condenser heat exchanger 102 may be wrapped around any portion of the water tank 114, including the top, bottom, and/or side walls of the water tank 114 so as to exchange heat with the water therein.
The condenser heat exchanger 102 may be any type of condenser configured to heat at least a portion of the water within the water tank 114. The condenser heat exchanger 102, for example, may be a coil-wrapped type, a roll-bonded, a micro-channel, or any other type of condenser heat exchanger suitable for the application. Although the disclosed technology is described in the context of water heater units used to heat water, the disclosed technology can be used in any fluid heater unit where heated fluid storage and production is needed.
The heat pump water heater 100 may also include an insulation jacket 106 disposed around at least the side wall 115 and the bottom wall of the water tank 114 and the condenser heat exchanger 102. In some instances, the insulation jacket 106 may surround the entire water tank 114. The insulation jacket 106 can include an insulation material, such as foam, fiberglass, cellulose, mineral wool, natural fibers, denim, or any other type of insulation material as may be appropriate for the particular application. The insulation material of the insulation jacket 106 may be surrounded by the outer casing 108. In other instances, the space between the outer casing 108 and the water tank 114 may be air. That is, no insulation material may be disposed between the outer casing 108 and the water tank 114.
Still referring to FIG. 1 , the heat pump water heater 100 does not include an air movement source to direct air across the natural convection evaporator heat exchanger 104. The natural convection evaporator heat exchanger 104 may be any type of heat exchanger which employs a two-phase heat transfer mechanism configured to absorb heat energy from the ambient to heat the refrigerant therein. The natural convection evaporator heat exchanger 104, for example, may be a roll-bonded or any other type of evaporator heat exchanger suitable for the application.
To increase the pressure and temperature of the refrigerant leaving the natural convection evaporator heat exchanger 104, the refrigerant line 103 connects the compressor 110 to the natural convection evaporator heat exchanger 104. Furthermore, to use the refrigerant as a heating medium in the condenser heat exchanger 102, the refrigerant line 103 connects the compressor 110 to the condenser heat exchanger 102.
In some instances, as depicted in FIG. 1 , the compressor 110 may be disposed within a compressor jacket 112 outside the outer casing 108. In other instances, as depicted in FIG. 3 , the compressor 110 may be disposed within a compressor jacket 312 located within the outer casing 108. The compressor 110 may be any type of compressor configured to increase the refrigerant pressure. The compressor 110, for example, may be a scroll compressor, a reciprocating compressor, a rotary compressor, a centrifugal compressor, or any other type of compressor suitable for the application.
Still referring to FIG. 1 , the heat pump water heater 100 may include a condensate collector tray 118 for collecting moisture drips that may form on the natural convection evaporator heat exchanger 104. The condensate collector tray 118 may be located below the bottom wall of the water tank 114 for the purpose of draining condensation outside and away from the heat pump water heater 100. The tray 118 may be any suitable size, shape or configuration. The tray 118 may be in communication within one or more drainpipes or the like for directing the condensate away from the heat pump water heater 100.
FIG. 2 is a schematic diagram illustrating a heat pump water heater 200 of one embodiment of the present disclosure. The heat pump water heater 200 is of a configuration similar to that illustrated in FIG. 1 , except that the natural convection evaporator 204 is on an exterior surface of the insulation jacket 106, which may increase airflow across the natural convection evaporator heat exchanger 204 due to the increase in air volume within the environment (e.g., utility room or the like) that the heat pump water heater 200 is located as compared to the air volume within the insulation jacket 106. In this manner, locating the natural convection heat exchanger 204 on an exterior of the heat pump water heater 200 may result in increased heat transfer between the air in the environment and the refrigerant within the natural convection evaporator heat exchanger 204.
More so, locating the natural convection heat exchanger 204 on an exterior of the heat pump water heater 200 may facilitate the ability to inspect the natural convection evaporator 204 more easily. For example, during the operation of the heat pump water heater 200, frost or ice may form on the natural convection evaporator 204, reducing the amount of airflow across the natural convection evaporator 204. Additionally, any dirt on the natural convection evaporator 204 may reduce airflow across the natural convection evaporator 204. By disposing the natural convection evaporator 204 on an exterior surface of the insulation jacket 106, facilitating inspection activities of the natural convection evaporator 204, the user may be able to ensure the refrigerant in the natural convection evaporator 204 is experiencing the requisite heat load—to prevent any liquid state refrigerant from traveling to the compressor 110 without employing air source directing air across the natural convection evaporator 204.
FIG. 3 is a schematic diagram illustrating a heat pump water heater 300 of one embodiment of the present disclosure. The heat pump water heater 300 is of a configuration similar to that illustrated in FIG. 1 or 2 , except that the compressor 110 is located inside the outer casing 108 separated from the bottom wall of the water tank 114 by an internal wall 302 of the insulation jacket 106. That is, in some instances, the insulation jacket 106 may include an internal wall 306, which separates the bottom wall of the water tank 114 from the compressor 110 located within the outer casing 108 of the insulation jacket 106. The compressor 110 may further be disposed within a compressor jacket 312 located within the outer casing 108. By disposing the compressor 110 and compressor jacket 312 on an interior of the outer casing 308, the heat pump water heater 300 is able to reduce the noise and vibration generated from the compressor 110 throughout the operation of the heat pump water heater 300.
The heat pump water heaters 100, 200, and 300 may include one or more controllers 142 for controlling the various operations and functions of the heat pump water heaters 100, 200, and 300 and the components thereof. The controller 142 may be an independent controller or integrated with the heat pump water heaters 100, 200, and 300 and components thereof. A single controller may be used or multiple controllers may be used to control the operation of the heat pump water heaters 100, 200, and 300. For example, each component of the heat pump water heaters 100, 200, and 300 may include a controller or one or more controllers may be used to control operation of the various components of the heat pump water heaters 100, 200, and 300. The controller 142 may be in wireless communication and/or hard wired to the heat pump water heaters 100, 200, and 300 and the components thereof. The controller 142 may include at least a memory and one or more processing units (or processor(s)). The processor(s) may be implemented as appropriate in hardware, software, firmware, or combinations thereof. Software or firmware implementations of the processor(s) may include computer-executable or machine-executable instructions written in any suitable programming language to perform the various functions described herein. Moreover, the processor may be associated with a network, a server, a computer, or a mobile device.
FIG. 4 is a flow diagram depicting an illustrative method 400 for heating water in accordance with one or more embodiments of the disclosure. At block 402 of method 400, a condenser heat exchanger is positioned about at least a portion of a water tank. For example, the condenser heat exchanger may be disposed about at least a portion of the side wall of the water tank. In other instances, the condenser heat exchanger may be disposed about at least a portion of the side wall and/or at least a portion of the bottom wall and/or top wall of the water tank.
At block 404 of the method 400, an insulation jacket is positioned about at least the side wall and the condenser heat exchanger. That is, the insulation jacket may surround at least a portion of the water tank and the condenser heat exchanger. In some instances, the insulation jacket may completely surround the water tank, including the side wall, the bottom wall, and the top wall of the water tank. In other instances, the insulation jacket may partially surround the water tank, including a portion or none of the side wall, the bottom wall, and/or the top wall of the water tank. In certain embodiments, the insulation jacket may include an outer casing and an insulation material disposed between the outer casing and at least a portion of the side wall, the bottom wall, and/or the top wall of the water tank. In some instances, the insulation material may be omitted. In such instances, the space between the outer casing of the insulation jacket and at least a portion of the side wall, the bottom wall, and/or the top wall of the water tank may be air.
At block 406 of the method 400, a natural convection evaporator heat exchanger may be positioned about the insulation jacket. In some instances, the natural convection evaporator heat exchanger may be disposed within the insulation jacket. For example, the natural convection evaporator heat exchanger may be disposed between the outer casing of the insulation jacket and at least a portion of the side wall, the bottom wall, and/or the top wall of the water tank. In some instances, the natural convection evaporator heat exchanger may be disposed on or about an inner wall of the outer casing. In other instances, the natural convection evaporator heat exchanger may be disposed on or about an exterior surface of the outer casing of the insulation jacket.
A block 408 of the method 400, heat may be exchanged by the natural convection evaporator heat exchanger with ambient air using natural convection and without an air movement device to direct air to the evaporator heat exchanger. In this manner, the heat pump water heater may rely on the natural convection evaporator to transfer heat to the refrigerant in order to heat the water in the water tank. When the refrigerant passes through the coils of the natural convection evaporator heat exchanger, the temperature difference between the ambient air of the water heater location and the refrigerant is used as a basis for warmer air to heat the refrigerant without the need for an air movement source (e.g., a fan or blower) directing air to the coils of the evaporator heat exchanger. As a result, the ambient air surrounding the natural convection heat exchanger may rise along the natural convection heat exchanger and exchange heat with the refrigerant therein.
For the purposes of the present document, the following terms and definitions are applicable to the examples and embodiments discussed herein. The term “natural convection evaporator” as used herein refers to any type of evaporator not employing an air source to direct air to the evaporator coils.
It should be apparent that the foregoing relates only to certain embodiments of the present application and that numerous changes and modifications may be made herein by one of ordinary skill in the art without departing from the general spirit and scope of the disclosure.
Although specific embodiments of the disclosure have been described, numerous other modifications and alternative embodiments are within the scope of the disclosure. For example, any of the functionality described with respect to a particular device or component may be performed by another device or component. Further, while specific device characteristics have been described, embodiments of the disclosure may relate to numerous other device characteristics. Further, although embodiments have been described in language specific to structural features and/or methodological acts, it is to be understood that the disclosure is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as illustrative forms of implementing the embodiments. 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

That which is claimed is:

1. A water heater, comprising:

a water tank;

a condenser heat exchanger disposed about at least a portion of the water tank; and

a natural convection evaporator heat exchanger disposed about at least a portion of the water tank,

wherein the natural convection evaporator heat exchanger is configured to exchange heat between water in the water tank and ambient air using natural convection.

2. The water heater of claim 1, further comprising a refrigerant configured to pass through a coil of the natural convection evaporator heat exchanger, wherein a temperature difference between the ambient air and the refrigerant is used as a basis for warmer air to heat the refrigerant based on the ambient air surrounding the natural convection evaporator heat exchanger rising along the natural convection evaporator heat exchanger and exchanging heat with the refrigerant therein.

3. The water heater of claim 1, further comprising an insulation jacket disposed about at least the water tank and the condenser heat exchanger.

4. The water heater of claim 3, wherein the natural convection evaporator heat exchanger is disposed on an exterior surface of the insulation jacket.

5. The water heater of claim 3, further comprising a compressor fluidly connected to the condenser heat exchanger and the natural convection evaporator heat exchanger.

6. The water heater of claim 5, wherein the compressor is at least one of a reciprocating compressor or a scroll compressor.

7. The water heater of claim 5, further comprising an outer casing surrounding the insulation jacket.

8. The water heater of claim 7, wherein the compressor is located outside the outer casing.

9. The water heater of claim 7, wherein the compressor is located inside the outer casing.

10. The water heater of claim 5, wherein the compressor is located inside a compressor jacket.

11. The water heater of claim 1, wherein the natural convection evaporator heat exchanger is a roll-bonded type evaporator.

12. The water heater of claim 1, wherein the natural convection evaporator heat exchanger is a micro-channel type heat exchanger.

13. The water heater of claim 1, wherein the condenser heat exchanger is at least one of a coil-wrapped type heat exchanger, a roll-bonded type heat exchanger, or a micro-channel type heat exchanger.

14. The water heater of claim 1, further comprising a condensate collector tray located below the water tank.

15. A water heater, comprising:

an outer casing;

a water tank disposed within the outer casing, wherein the water tank comprises a bottom wall, a top wall, and a side wall extending between and connected to the bottom wall and the top wall;

a condenser heat exchanger surrounding at least a portion of the side wall;

an insulation jacket disposed around at least the side wall and the condenser heat exchanger between the side wall and the outer casing;

a natural convection evaporator heat exchanger disposed about the insulation jacket; and

a compressor fluidly connected to the condenser heat exchanger and the natural convection evaporator heat exchanger,

wherein the water heater does not employ a fan to direct air to the natural convection evaporator heat exchanger.

16. The water heater of claim 15, wherein the natural convection evaporator heat exchanger is disposed on an exterior surface of the insulation jacket.

17. The water heater of claim 15, wherein the natural convection evaporator heat exchanger is a micro-channel type heat exchanger.

18. The water heater of claim 15, further comprising a condensate collector tray located below the bottom wall.

19. A method of heating water using a heat pump water heater, the method comprising:

positioning a condenser heat exchanger about at least a portion of a side wall of a water tank;

positioning an insulation jacket about at least the side wall and the condenser heat exchanger;

positioning a natural convection evaporator heat exchanger about the insulation jacket;

connecting a compressor to the condenser heat exchanger and the natural convection evaporator heat exchanger; and

exchanging heat, by the natural convection evaporator heat exchanger, with ambient air using natural convection and without an air movement device to direct air to the natural convection evaporator heat exchanger.

20. The method of claim 17, wherein the natural convection evaporator heat exchanger is disposed on an exterior surface of the insulation jacket.