The present invention relates generally to an evaporator for use with a water heating device, and more particularly to an evaporator for use with a heat pump water heater. The disclosed technology includes an evaporator (e.g., a microchannel evaporator) that has a shroud-like structure such that the evaporator can also function as an air movement shroud as described more fully herein.
A heat pump water heater typically includes a heat pump configured to acquire heat from air ambient and convey the acquired heat to water in the tank of the water heater via a heat exchanger. A fan is often used to direct warm ambient air across a heat exchanger (e.g., an evaporator) through which a refrigerant is flowing in liquid form. The warm ambient air will increase the temperature of the liquid refrigerant, causing the refrigerant to transition from a liquid state to a vapor state. A compressor will typically increase the pressure of the vapor refrigerant, thereby raising the temperature of the vapor refrigerant, and the heated vapor refrigerant will be directed through a condenser coil surrounding the water tank, which will increase the temperature of the water in the tank. As the water in the tank acquires heat from the vapor refrigerant, the vapor transitions back to a liquid state, and the cycle can repeat. Heat pump water heaters can provide a variety of advantages including energy savings and costs savings, as heat pump water heaters can transfer heat from ambient air to water in a storage tank, as opposed to solely heating water with a resistive heating element, for example.
Microchannel heat exchangers have been designed to improve heat transfer efficiency as compared to finned-tube evaporators. Microchannel heat exchangers can include a plurality of ports configured to carry refrigerant. Microchannel heat exchangers can provide a variety of advantages including high heat transfer ratios, reduced refrigerant charge, small and compact design, low weight, and high energy efficiency. However, microchannel heat exchangers can be susceptible to freezing and/or fowling. When ambient air is directed across the microchannel heat exchanger, moisture and condensate from the ambient air can collect on exterior surfaces of the microchannel heater. Without a pathway to remove accumulated moisture and/or condensate, freezing can occur, thereby decreasing the lifespan of the microchannel heat exchanger and increasing the need for continuous maintenance.
These and other problems can be addressed by the technologies described herein. Examples of the present disclosure relate generally to an evaporator having a plurality of sidewalls, where at least one sidewall can function as a heat exchanger.
The disclosed technology includes an evaporator having a plurality of sidewalls arranged to define an internal cavity. At least one of the sidewalls can include a plurality of refrigerant channels. The evaporator can further include a top plate covering the internal cavity.
Each refrigerant channel can include a plurality of ports configured to provide a refrigerant flow path from a refrigerant inlet to a refrigerant outlet. Each refrigerant channel can be angled such that ambient air can be directed across the plurality of refrigerant channels and into the internal cavity.
The disclosed technology further includes a heat pump water heater including a first portion and a second portion. The first portion can include an evaporator and a compressor. The evaporator can have a plurality of sidewalls arranged to define an internal cavity. At least one of the sidewalls can include a plurality of refrigerant channels. A top plate can cover the internal cavity. The top plate can include an aperture configured to receive a fan. The second portion can include a storage tank and a condenser coil in thermal communication with the storage tank.
These and other aspects of the present disclosure are described in the Detailed Description below and the accompanying figures. Other aspects and features of the present disclosure will become apparent to those of ordinary skill in the art upon reviewing the following description of specific examples of the present disclosure in concert with the figures. While features of the present disclosure may be discussed relative to certain examples and figures, all examples of the present disclosure can include one or more of the features discussed herein. Further, while one or more examples may be discussed as having certain advantageous features, one or more of such features may also be used with the various other examples of the disclosure discussed herein. In similar fashion, while examples may be discussed below as devices, systems, or methods, it is to be understood that such examples can be implemented in various devices, systems, and methods of the present disclosure.
Reference will now be made to the accompanying figures, which are not necessarily drawn to scale, and wherein:
The disclosed technology relates an evaporator having a plurality of sidewalls arranged to define an internal cavity. At least one of the sidewalls can include a plurality of refrigerant channels such that at least one of the sidewalls can function as a heat exchanger. The refrigerant channels can extend from a refrigerant inlet to a refrigerant outlet and can be stacked upon one another to create parallel refrigerant channels. Each refrigerant channel can include a plurality of ports extending the length of the refrigerant channel. The ports can be configured to direct refrigerant from the refrigerant inlet to the refrigerant outlet. A plurality of fins can be disposed between adjacent refrigerant channels to facilitate the transfer of heat from ambient air to the refrigerant flowing through the ports. Each of the refrigerant channels can be attached to the refrigerant inlet and the refrigerant outlet at an angle. The angled refrigerant channels can facilitate directing ambient air across the refrigerant channels and fins and to the internal cavity, which can reduce turbulence and/or parasitic loss of static pressure for the system, thereby eliminating the need for a separate air movement shroud and improving efficiency of the system. Additionally, the angled refrigerant channels can provide a flow path for accumulated moisture and/or condensate on the exterior surfaces of the refrigerant channels and/or fins. The flow path can allow accumulated moisture and/or condensate to shed from the components of the evaporator, thereby minimizing freezing and/or fouling. As will be appreciated, if ice crystals nucleate on the fins and continue to grow and/or expand, the ice/frost formation can cause a blockages and/or restriction of the air flow across the heat exchanger, which will typically diminish the efficiency of the heat pump system and could ultimately cause the heat pump system to completely shut down due to integrated failsafe features. By minimizing the chance of components of the evaporator freezing and/or fouling, the lifespan of the evaporator and/or the heat pump system can be extended (e.g., by preventing damage to the heat pump system).
The disclosed technology will be described more fully hereinafter with reference to the accompanying drawings. This disclosed technology can, however, be embodied in many different forms and should not be construed as limited to the examples set forth herein. The components described hereinafter as making up various elements of the disclosed technology are intended to be illustrative and not restrictive. Such other components not described herein may include, but are not limited to, for example, components developed after development of the disclosed technology.
In the following description, numerous specific details are set forth. But it is to be understood that examples of the disclosed technology can be practiced without these specific details. In other instances, well-known methods, structures, and techniques have not been shown in detail in order not to obscure an understanding of this description. References to “one embodiment,” “an embodiment,” “example embodiment,” “some embodiments,” “certain embodiments,” “various embodiments,” “one example,’ “an example,” “some examples,” “certain examples,” “various examples,” etc., indicate that the embodiment(s) and/or example(s) of the disclosed technology so described may include a particular feature, structure, or characteristic, but not every embodiment necessarily includes the particular feature, structure, or characteristic. Further, repeated use of the phrase “in one embodiment” or the like does not necessarily refer to the same embodiment, example, or implementation, although it may.
Throughout the specification and the claims, the following terms take at least the meanings explicitly associated herein, unless the context clearly dictates otherwise. The term “or” is intended to mean an inclusive “or.” Further, the terms “a,” “an,” and “the” are intended to mean one or more unless specified otherwise or clear from the context to be directed to a singular form.
Unless otherwise specified, the use of the ordinal adjectives “first,” “second,” “third,” etc., to describe a common object, merely indicate that different instances of like objects are being referred to, and are not intended to imply that the objects so described should be in a given sequence, either temporally, spatially, in ranking, or in any other manner.
Unless otherwise specified, all ranges disclosed herein are inclusive of stated end points, as well as all intermediate values. By way of example, a range described as being “between approximately 2 and approximately 4” includes the values 2 and 4 and all intermediate values within the range. Likewise, the expression that a property “can be in a range from approximately 2 to approximately 4” (or “can be in a range from 2 to 4”) means that the property can be approximately 2, can be approximately 4, or can be any value therebetween.
As used herein, the term “shroud” is used to describe a housing or similar structure. As described more fully herein, the disclosed shrouds can substantially direct airflow therethrough. For example, a shroud can direct airflow from an inlet (e.g., over evaporator coils) to an outlet (e.g., a fan aperture).
Referring now to the drawings,
The evaporator 200 can include a top plate 204 covering the internal cavity 214. The top plate 204 can be made substantially of a metal. By way of example, the top plate 204 can be made substantially of aluminum, copper, steel, or alloys thereof. The top plate 204 can be made of plastic or anything other material. The top plate 204 can have an aperture sized to receive a fan 206. The fan 206 can include any type of air movement device, such as an axial-flow fan, a centrifugal fan, or the like. The fan 206 can be positioned at the center of the top surface 204, for example. Alternatively, the fan 206 can be positioned off-center at any location on the top plate 204. A filter 216 can be disposed at or proximate an outlet of the fan 206. The filter 216 can prevent contaminant particles (e.g., dust particles) within the ambient air from being drawn into the internal cavity 214 of the evaporator 200. The filter 216 can be particularly beneficial when the evaporator 200 is a component of a heat pump water heater that is located within a garage or attic of a home or building.
As will be appreciated, the evaporator 200 is expressly described herein as being configured to be located on top of a tank or vessel. For example, the described evaporator can be used with, and located on top of, a tank or vessel of a water heater system. It is to be understand that the disclosed technology is not limited to such configurations. For example, the evaporator 200 can include a bottom plate (e.g., in lieu of, or in addition to, the top plate 204), and/or the evaporator 200 can be configured to be located beneath or below a tank or vessel of a water heater system.
The evaporator 200 can include a refrigerant inlet 208 and a refrigerant outlet 210. The refrigerant inlet 208 and the refrigerant outlet 210 can be vertically oriented tubes. The refrigerant inlet 208 and the refrigerant outlet 210 can be substantially cylindrical tubes having a circular cross-section. Alternatively, the refrigerant inlet 208 and the refrigerant outlet 210 can have any shape and have any cross-sectional shaped, including but not limited to a substantially ellipsoid, rectangular, or polygonal cross-section.
The refrigerant inlet 208 and the refrigerant outlet 210 can be attachment points for a plurality of refrigerant channels 212 extending from the refrigerant inlet 208 to the refrigerant outlet 210. At least one of the sidewalls 202 can include the plurality of refrigerant channels 212 such that at least one of the sidewalls 202 can be configured to function as a heat exchanger. As illustrated in
A first end of each refrigerant channel 212 can be affixed to the refrigerant inlet 208 and a second end of each refrigerant channel 212 can be affixed to the refrigerant outlet 210 such that the refrigerant inlet 208, the refrigerant outlet 210, and the refrigerant channels 212 are in fluid communication. The first end of each refrigerant channel 212 can be affixed to the refrigerant inlet 208 and the second end of each refrigerant channel 212 can be affixed to the refrigerant outlet 210 at an angle, as further discussed herein. The refrigerant channels 212 can be vertically stacked upon one another to form parallel refrigerant channels 212. The refrigerant channels 212 can be equally spaced apart from one another such that a gap between adjacent refrigerant channels 212 is created. By way of example, each refrigerant channel 212 can be spaced apart from an adjacent channel by approximately 6 millimeters to approximately 12 millimeters. The evaporator 200 can include any number of channels 212. The evaporator 200 can have a height H that is between approximately 5 inches and approximately 20 inches.
Each refrigerant channel 212 can have a substantially flat exterior surface. Alternatively, some or all of the refrigerant channels 212 can have surface features. By way of example, some or all of the refrigerant channels 212 can have bends, twists, turns, protrusions or other geometries, and the like. These surface features can provide aerodynamic enhancements when ambient air is directed across the plurality of refrigerant channels and into the internal cavity 214. As will be appreciated, that particular geometry of a given refrigerant channel 212 or set of refrigerant channels 212 can be designed to provide optimal air flow for a given application, thereby provided an increased or maximized efficiency and/or performance for the corresponding design and application.
The plurality of refrigerant channels 212 can be made substantially of a metal. The plurality of refrigerant channels 212 can be made substantially of aluminum and/or aluminum alloys. Optionally, the plurality of refrigerant channels 212 can have a hydrophobic coating. The hydrophobic coating can prevent excess moisture and/or condensate from accumulating on the refrigerant channels 212.
Additionally, by having multiple sidewalls 202 include refrigerant channels 212, ambient air can be directed across the refrigerant channels 212 extending along a large exterior surface area of the evaporator 200. By increasing the exterior surface area in which ambient air can be directed across the refrigerant channels 212 as compared to the prior art, the evaporator 200 can have improved heat transfer capabilities. The improved heat transfer capabilities can allow the size of the fan 206 can be reduced. When the size of the fan 206 is reduced, efficiency can be increased and noise during operation can be decreased.
Each refrigerant channel 212 can include a plurality of ports 302. By way of example, each refrigerant channel 212 can include between approximately 25 and approximately 30 ports 302. Each port 302 can provide a refrigerant flow path. By way of example, refrigerant from the refrigerant inlet 208 can flow through the plurality of ports 302 of the plurality of refrigerant channels 212 and to the refrigerant outlet 210. Each port 302 can extend from the refrigerant inlet 208 to the refrigerant outlet 210 such that the ports 302 traverse the entire length of refrigerant channel 212. The ports 302 can be substantially cylindrical and have a circular cross-section. Alternatively, the ports 302 can be partially flattened such that the ports 302 have a substantially rectangular, oval, ellipsoid, or the like cross-section. Each port 302 can have a diameter of between approximately 0.5 millimeter and approximately 1.5 millimeters. The ports 302 can be made substantially of a metal and/or metal alloy. By way of example, the ports 302 can be made substantially of aluminum and/or aluminum alloys.
Within each gap between adjacent refrigerant channels 212, a fin 304 can be positioned to provide structural stability and enhanced heat transfer capabilities when ambient air is directed across the refrigerant channels 212. The fin 304 can be affixed to each adjacent refrigerant channel 212 at a plurality of attachment points along each refrigerant channel 212. The fin 304 can be affixed to each adjacent refrigerant channel by furnace brazing, welding, or any other attachment mechanism. Each fin 304 can have any configuration that creates a plurality of air flow passages that direct ambient air across the refrigerant channels 212 and/or fins 304 and into the internal cavity 214. Each fin 304 can be a unitary piece of metal having a substantially wave-like configuration, as illustrated in
Some or all of the fins 304 can have a downward angle configuration. For example, some of all of the fins 304 can be angled upward and radially inward toward the center of the internal cavity 214. Alternatively, some of all of the fins 304 can be angled downward and radially inward toward the center of the internal cavity 214. The fins 304 can be angled regardless of whether the refrigerant channels 212 are angled. Further, the fins 304 can be angled in a different direction and/or to a different degree than an angle of the refrigerant channels 212.
Moisture from ambient air flowing across the refrigerant channels 212 and fins 304 can condensate out of the air and accumulate on the exterior surfaces of the refrigerant channels 212 and/or fins 304. During some operating conditions of a heat pump water heater, the moisture condensing can create frost and/or ice on the exterior surfaces of the refrigerant channels 212 and/or fins 304. Freezing on the various components of the evaporator 200 can reduce the efficiency and/or lifespan of the evaporator 200 and can lead to the need of frequent maintenance.
When each refrigerant channel 212 is angled as illustrated in
As illustrated in
When each refrigerant channel 212 is angled as illustrated in
The sidewall(s) 202 of the evaporator 200 that do not include the plurality of refrigerant channels 212 (e.g., sidewall 202d) can provide structure and stability and protect the components of the heat pump water heater 400 disposed within the internal cavity 214. The sidewall 202d can be made of any insulating material. By way of example, the sidewall 202d can be made of insulating metal(s) and/or plastic. Unlike the prior art heat pump water heater 100 illustrated in
The top plate 204 can include an aperture sized to receive the fan 206. The top portion 402 can include a compressor 406. The compressor 406 can be disposed within the internal cavity 214 of evaporator 200.
The bottom portion 404 can include a storage tank 410. The storage tank 410 can store fluid, including water. The storage tank 410 can receive unheated fluid via an inlet 412 and output heated fluid via an outlet 414. A condenser coil 416 can be disposed proximate the storage tank 410. As illustrated in