Hybrid Water Heater System and Methods of Use

The invention described herein is directed to a water heater system and, more particularly, a water heater system including a heat pump system.

Traditional water heaters lack adjustability that can impact the functionality and efficiency of the water heater. Therefore, a need exists to modify the water heater functionality and control to increase performance ability, efficiency, and comfort provided for a user.

This background section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with supporting information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.

The exemplary embodiments disclosed herein describe an advantageous hybrid water heater system including a heat pump system and a heating element.

In one embodiment, a hybrid water heater system includes a body which includes a water storage tank. The hybrid water heater system includes a heat pump system mounted relative to the body and in thermal connection with the water storage tank, and a heating element mounted relative to the body and in fluid and thermal connection with the water storage tank. The hybrid water heater system is configured to selectively activate the heat pump system, the heating element, or the heat pump system and the heating element based on a desired output.

In another embodiment, a water heater system includes a body which includes a water storage tank. The water heater system includes a heat pump system mounted relative to the body and in thermal connection with the water storage tank. The water heater system is configured to selectively activate the heat pump system based on a desired output, wherein the desired output is selected from the list comprising water temperature, system efficiency, decibel level, time for water usage, and combinations thereof.

In another embodiment, a method of selecting a power mode of a hybrid water heater system is provided, the hybrid water heater system includes a body including a water storage tank, a heat pump system mounted relative to the body and in thermal connection with the water storage tank, and a heating element mounted relative to the body and in fluid and thermal connection with the water storage tank. The method includes assessing a temperature of water within the water storage tank over a period of the time to determine which power mode is required. The method includes determining whether the temperature is within a predetermined range or outside of the predetermined range, wherein if the temperature is within the predetermined range activating a low power mode, and if the temperature is outside of the predetermined range activating a boost power mode.

In another embodiment, a method of applying pattern learning to a water heater system is provided, the water heater system includes a body including a water storage tank, a heat pump system mounted relative to the body and in thermal connection with the water storage tank. The method includes tracking usage of the water heater system at predetermined increments to identify patterns. The method includes operating the water heater system beginning a period of time before the identified pattern.

As used herein, “a”, “an”, and “the” refer to both singular and plural referents unless the context clearly dictates otherwise.

As used herein, the term “about” refers to a measurable value such as a parameter, an amount, a temporal duration, and the like and is meant to include variations of +/−15% or less, preferably variations of +/−10% or less, more preferably variations of +/−5% or less, even more preferably variations of +/−1% or less, and still more preferably variations of +/−0.1% or less of and from the particularly recited value, in so far as such variations are appropriate to perform in the invention described herein. Furthermore, it is also to be understood that the value to which the modifier “about” refers is itself specifically disclosed herein.

As used herein, spatially relative terms, such as “beneath”, “below”, “lower”, “above”, “upper”, “front”, “back”, “side”, “left”, “right”, “rear”, “top”, “bottom”, and the like, are used for ease of description to describe one element or feature's relationship to another element(s) or feature(s). It is further understood that the terms “front”, “back”, “left”, and “right” are not intended to be limiting and are intended to be interchangeable, where appropriate. Further, it should be noted that the terms “first,” “second,” and the like herein do not denote any order, quantity, or relative importance, but rather are used to distinguish one element from another.

As used herein, the terms “comprise(s)”, “comprising”, and the like, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

As used herein, the terms “configure(s)”, “configuring”, and the like, refer to the capability of a component and/or assembly, but do not preclude the presence or addition of other capabilities, features, components, elements, operations, and any combinations thereof.

All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other. Each range disclosed herein constitutes a disclosure of any point or sub-range lying within the disclosed range.

All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”), is intended merely to better illustrate the invention and does not pose a limitation on the scope of the invention or any embodiments unless otherwise claimed.

Any combination or permutation of features, functions, and/or embodiments as disclosed herein is envisioned. Additional advantageous features, functions, and applications of the disclosed systems, methods, and assemblies of the present disclosure will be apparent from the description which follows, particularly when read in conjunction with the appended figures. All references listed in this disclosure are hereby incorporated by reference in their entireties.

The present disclosure describes a water heater system and, more particularly, a hybrid water heater system including a heat pump system and a heating element. Referring to, a hybrid water heater systemincludes a body, a heat pump systemand a heating element. The bodyof the hybrid water heater systemmay be at least partially a storage tankfor holding a fluid (e.g., water). The heat pump systemmay be in thermal connection with the storage tankof the hybrid water heater system. For example, the heat pump systemmay be in thermal connection with water within the storage tankof the hybrid water heater system. The heating elementmay be in thermal and fluid connection with the storage tankof the hybrid water heater system. For example, the heating elementmay be in fluid and thermal connection with water within the storage tankof the hybrid water heater system. Although depicted as a combined system, it should be understood that the heat pump systemand the heating elementmay be separate systems, without departing from the spirit/scope of this disclosure. For example, a water heater system may include a heating element that is fluidly and/or thermally connected to a heat pump system, where the heat pump system is separate from the water heater system.

The hybrid water heater systemincludes a water inletand a water outlet. The water inletand the water outletmay be fluidly connected to the storage tankof the bodyof the hybrid water heater system. The water inlettypically receives water that is colder than the water released by the water outlet. In some instances, the water inletis fluidly connected to a water source (e.g., municipal water, wells, lakes/ponds, streams) and the water outletis fluidly connected to a fixture, device, appliance, or the like. The hybrid water heater systemmay include at least one temperature monitoring apparatus (not shown) positioned to measure the water temperature in close proximity to the water outlet.

The heat pump systemincludes an air inletand an air outlet. The air inletdraws air from the room (not shown) where the hybrid water heater systemis installed and/or from an area outside the room (e.g., another room, outside the building), and the air outletexpels air into the room (not shown) where the hybrid water heater systemis installed and/or into an area outside the room (e.g., another room, outside the building). The air inletand the air outletare fluidly connected to an evaporatorand a compressor. The evaporatorand the compressorare fluidly connected with each other by a pipe, thereby creating the closed-loop heat pump system. The evaporatormay include an evaporator fan. A fluid (e.g., a refrigerant) travels through the evaporatorand the compressorby way of the pipe. The pipemay include additional coilingpositioned relative to the storage tank. For example, the coilingof the pipemay be in close proximity to the water inlet. An expansion valvemay be in fluid connection with the pipe.

In operation and as depicted in, heat from the air at the air inletis absorbed by the refrigerant within the evaporator. The evaporator fanpulls the air from outside of the hybrid water heater systeminto the evaporator. The refrigerant is delivered to the compressoras a low-pressure cool gas, as indicated by the arrows in relation to the pipe. The air travels through the heat pump system and is expelled through the air outlet. The air temperature at the air outletis colder than the air temperature at the air inlet. The refrigerant exiting the compressoris a high-pressure hot gas which travels within the pipeto the coiling. Within the coiling, the refrigerant becomes a high-pressure warm liquid and heats the water within the storage tank. The refrigerant within the pipetravels through the expansion valveand into the evaporatoras a low-pressure cold liquid. The process utilized by the heat pump systemis repeated, as necessary. Positioned relative to and in fluid connection with the water within the storage tank, the heating elementmay heat the water before it exits through the water outlet. As depicted, the heating elementis in close proximity to the water outletsuch that it supplements the heating process from the heat pump system. However, it should be understood that the heating elementmay be positioned at any location within the storage tank, such as, any location along the height of the storage tank.

In some embodiments, the operating parameters of the hybrid water heater systemmay be optimized to fully utilize the input current rating of the hybrid water heater system. For example, adjusting the operating parameters of the heat pump systemand/or the heating elementsuch that the sum of the currents of the heat pump systemand the heating elementare about equal to the current rating of the hybrid water heater system. The operating parameters of the hybrid water heater systemmay be controlled by at least one pulse width modulation (PWM) controller. In some instances, less current may be allocated to the heat pump systemversus the heating element. In other instances, the current allocated to the heat pump systemand the heating elementmay be about equal Allocating more current to the heat pump systemmay increase the overall efficiency of the hybrid water heater systemand may increase the temperature of the water at the water outletof the hybrid water heater systemcompared to a hybrid water heater system that allocates less current to the heat pump system

In one embodiment, current may be allocated to the heat pump systembased, in part, on the max current rating of the heat pump system. For example, current may be allocated to the heat pump systemthat is equal to or less than the max current rating thereof. The max current rating may be determined, at least in part, by the desired speed of the compressor. The desired speed of the compressormay be equal to or less than the max speed of the compressor. The remaining current in excess of the amount allocated to the heat pump systemis allocated to the heating element.

illustrate the results of operating the hybrid water heater systemat different compressor speeds, including 3,000 revolutions per minute (RPM), 4,200 RPM, and 5,500 RPM.

illustrates the temperature of the water within the storage tanknear the water outletwhere the hybrid water heater systemis operated at different compressor speeds, including 3,000 RPM, 4,200 RPM, and 5,500 RPM.depicts the temperature (° C.) along the Y-axis and the timing (seconds) along the X-axis. The hybrid water heat systemoperating at 5,500 RPM produced a lower temperature drop beginning before the 3,500 second mark versus the hybrid water heater systemoperating at 3,000 and 4,200 RPM.

illustrates the total heating capacity of the hybrid water heater systemoperating at different compressor speeds, including 3,000 RPM, 4,200 RPM, and 5,500 RPM during the First Hour Rating test. The sum of the input current of the hybrid water heater system, including the current of the heat pump system and the heating element is the same for each of the compressor speeds.depicts the power (watts) along the Y-axis and the timing (seconds) along the X-axis. As shown, the input current into the hybrid water heater systemis the same for each of the compressor speeds, but the higher the compressor speed, the more heating capacity that is produced.

illustrates the upper element power of the hybrid water heater system operating at various compressor speeds, including 3,000 RPM, 4,200 RPM, and 5,500 RPM, where the power (watts) is depicted along the Y-axis and the timing (seconds) is depicted along the X-axis.illustrates that the upper element power is lower at higher speeds.

illustrates the compressor power of the hybrid water heater system operating at various compressor speeds, including 3,000 RPM, 4,200 RPM, and 5,500 RPM, where the power (watts) is depicted along the Y-axis and the timing (seconds) is depicted along the X-axis.illustrates that the compressor power is higher at higher speeds.

As explained above, the sum of the input currents to the hybrid water heater system, including the current to the heat pump systemand the heating element, is the same for all speeds of the compressor.together depict that by allocating more current to the heat pump system(i.e., the compressor runs at a higher speed, for example 5,500 RPM), the hybrid water heater systemachieves a higher total heating capacity as shown specifically in.

Table 1, shown below, compares the number of gallons of hot water the hybrid water heater systemcan supply per hour, also referred to as the first hour rating, for systems operated with fixed upper element (UE) power and maximized current. In the maximized current scenario, more current is allocated to the heat pump system such that the compressor can be operated at higher speeds. As shown in Table: 1, the 3,000 RPM hybrid water heater system operated at a maximum current produced about three (3) percent more hot water per hour than the 3,000 RPM hybrid water heater system operated at fixed UE power. The 4,200 RPM hybrid water heater system operated at a maximum current produced about one and a half (1.5) percent more hot water per hour than the 4,200 RPM hybrid water heater system operated at fixed UE power. The 5,500 RPM hybrid water heater system operated at a maximum current produced about one-half (0.5) of a percent more hot water per hour than the 5,500 RPM hybrid water heater system operated at fixed UE power. Thus, operating the hybrid water heater system at the maximized current produces more hot water versus the fixed UE power system, at any of the tested compressor speeds.

In some embodiments, the hybrid water heater systemmay include pattern learning capabilities. In a non-limiting example, the hybrid water heater systemincludes water usage pattern learning capabilities to optimize hot water availability and/or hot water temperature. Water usage patterns can be determined for hot water usage, power usage, tank temperature, and other parameters applicable to water heaters. It should be understood, however, that although the hybrid water heater systemis described, water heaters including only the heat pump system may also include pattern learning capabilities. Therefore, discussion of the hybrid water heater systemalso includes water heaters with only a heat pump system, unless expressly stated otherwise. The hybrid water heater systemmay monitor and/or record the amount of hot water used at a given day and time. Based at least in part on this information, the hybrid water heater systemmay track hot water usage patterns for a given period of time (e.g., a day, a week, a month, a year). The hybrid water heater systemmay utilize the information from tracking water usage to ensure there is hot water available by and/or before a given day and time. For example, the heat pump systemand/or the heating elementmay begin heating the water within the storage tankof the hybrid water heater systema period of time before the hot water is required (e.g., a time of a given day).

Referring to, the hybrid water heater systemprepares a water usage profile at adjustable increments per day and based on that information, pre-heats the water within the storage tankto ensure hot water is available at a given time based on the water usage profile.illustrates a bar graph showing an exemplary water usage profile over a period of.hours, where the water usage volume (L) is depicted along the Y-axis and the water usage time stamp (hr.) is depicted along the X-axis. As shown, water usage during hours 0, 1, 1.5, and 6.5 are greater than during the other hours.illustrates a graph showing the effect of pre-heating the water within the storage tank, where the tank temperature (° C.) is depicted along the Y-axis and the water usage time stamp (hr.) is depicted along the X-axis. As shown, the hybrid water heater systemutilizing the pre-heat features maintains a higher water temperature within the storage tankversus typical water heater systems.

The hybrid water heater systemmay operate in a low power mode or in a boost power mode to provide water on demand and/or in preparation for use. The low power mode may have increased efficiency compared to the boost power mode. It should be understood, however, that although the hybrid water heater systemis described, water heaters including only the heat pump system may also include a low power mode or a boost power mode. Therefore, discussion of the hybrid water heater systemalso includes water heaters with only a heat pump system, unless expressly stated otherwise. The hybrid water heater systemmay select which power mode is required based on the hot water requirements. The hybrid water heater systemmay automatically switch between the low power mode and the boost power mode based on various water usage scenarios. For example, immediate water usage versus water usage at a time in the future. The selection of the power mode may also at least partially depend on the current temperature of the water within the storage tank. For example, if the water was recently heated to a desired temperature and a request for hot water is received within a period of time, the hybrid water heater systemmay determine that the water can be heated using the low power mode.

In some examples, the hybrid water heater systemmay utilize the low power mode and begin heating the water within the storage tankwith enough time to ensure hot water is available at a desired time. In some examples, the hybrid water heater systemmay utilize the boost power mode and begin heating the water within the storage tankwith enough time to ensure hot water is available at a desired time. In other examples, the hybrid water heater systemmay utilize the low power mode to begin heating the water within the storage tankto a predetermined water temperature and alternatively use the boost power mode to rapidly raise the water temperature when an immediate request for hot water is received. In some examples, the hybrid water heater systemmay utilize the boost power mode to heat water within the storage tankto accommodate an immediate hot water requirement.

In some instances, the low power mode of the hybrid water heater systemrelates to using predominantly the heat pump system. In some instances, the boost power mode of the hybrid water heater systemrelates to using both the heat pump systemand the heating element.

Referring to, the hybrid water heater systemmay assess the rate of change in temperature of the tank over a period of the time to determine which power mode is required, as indicated by reference number. Reference numberindicates whether the rate of change in temperature is within a predetermined range or outside of a predetermined range. If the rate of change in temperature is within the predetermined range, the low power mode may be utilized, as indicated by reference number. If the rate of change in temperature is outside the predetermined range, the boost power mode may be utilized, as indicated by reference number. For example, the low power mode may utilize only the heat pump systemof the hybrid water heater systemto heat the water within the storage tank. For example, the boost power mode may utilize both the heat pump systemand the heating elementof the hybrid water heater systemto heat the water within the storage tank.

In some embodiments, the noise produced by the hybrid water heater systemmay be optimized to a desired decibel level. The operation of at least one component of the hybrid water heater systemmay be adjusted to decrease or increase the decibel output from the systemwhile maintaining a desired heating performance (e.g., hot water capacity, system efficiency, water temperature). In some instances, the hybrid water heater systemmay adjust at least one component to decrease or increase the decibel output from the systemto be consistent with the ambient noise surrounding the hybrid water heater system.

The decibel level output of the hybrid water heater systemmay be automatically adjusted as the decibel level within the room changes. In operation, the hybrid water heater systemmay monitor the noise within the room for a predetermined period of time before adjusting the at least one component of the systemto decrease or increase the decibel level output of the system. Doing so ensures the noise within the room is constant and not merely a noise spike (e.g., a user operating a vacuum). The hybrid water heater systemmay include preset decibel levels that may be selectable by a user based on the user's desired decibel level output of the system. The selectable preset decibel levels (not shown) may also provide the user with comparable efficiency settings of the hybrid water heater system. Therefore, the user can select a preset decibel level that also ensures their hot water needs are maintained based on the efficiency of the systemat the selected decibel level.

To adjust the decibel level output of the hybrid water heater system, at least one component of the systemmay be adjusted. For example, the speed of the evaporator fanmay be reduced to decrease the decibel level of the hybrid water heater system. In other instances, the speed of the compressor may be reduced to decrease the decibel level of the hybrid water heater system. In some instances, the speed of the evaporator fanand the speed of the compressor may be reduced. The speed of the evaporator fanmay be reduced before the speed of the compressor.

Table 2, provided below, depicts the effect fan speed has on the water heating performance of the hybrid water heater system. As shown in the table, the performance of the hybrid water heater systemcan maintain, or nearly maintain, a consistent tank water temperature at various speeds of the compressorand the evaporator fan. In some cases, reducing the speed of evaporator fanmay also produce a lower decibel level output of the hybrid water heater system. Thus, in some instances, and as shown below in Table 2, decreasing the evaporator fanmay reduce the noise output of the hybrid water heater systemwith minimal or no impact on the heating performance (i.e., C/minute) of the hybrid water heater system. For example, when the speed of the compressoris maintained at 3,000 RPM, and the speed of the evaporator fanis changed from 1,900 RPM to 1,700 RPM, the difference in the change in water heated rate is a decrease of 0.001° C./minute. In some instances, the speed of the evaporator fanmay be adjusted before the speed of the compressor is adjusted. The adjustment order may be beneficial in reducing the noise level of the hybrid water heater system.

In another embodiment, the hybrid water heater systemmay be configured to remove radon from at least the room where the systemis installed. Referring to, a radon mitigation assemblyincludes the hybrid water heater systemwhich is positioned within a room. The radon mitigation assemblyincludes an inlet ductthat extends through the floorof the roomsuch that an inlet endof the inlet ductis open to the areabelow the floor(e.g., ground, soil). The radon mitigation assemblyincludes an outlet ductthat extends through an exterior boundary (e.g., roof, exterior wall) such that an outlet endof the outlet ductis open to the atmosphereoutside of the room. The radon mitigation systemis in fluid communication with the heat pump systemof the hybrid water heater system. The compartment of the heat pump systemof the hybrid water heater systemmay include additional sealing to enclose the heat pump systemsuch that air leakage from the compartment is reduced. In some cases, air leakage from the compartment of the heat pump systemmay be significantly reduced almost to, or at the point of, elimination.

In operation, the radon mitigation assemblyis configured to detect a predetermined level of radon or periodically measures the level of radon. The predetermined level of radon may be a radon concentration below levels that are unsafe for humans and animals. The predetermined level of radon may be a radon concentration level that includes the lowest concentration level recognized as producing an environment that is unsafe for humans and animals. However, the predetermined level of radon may be set by a user.

In one embodiment, once the predetermined radon level is realized or a predetermined period of time has lapsed, the radon mitigation assemblyis activated. If activation of the radon mitigation assemblyoccurs while the hybrid water heater systemis producing hot water and/or has been requested to produce hot water, the speed of the evaporator fanof the hybrid water heater systemis increased. The evaporator fanmay pull air from the environment around the hybrid water heater system, as done in the normal course of operation. Thus, the air travels into the evaporator, through the evaporator fan, and into the compressorof the heat pump systemof the hybrid water heater system. The air is then exhausted from the outlet duct, which is in fluid communication with the compressorof the heat pump system. The air is exhausted into the atmospherefrom the outlet endof the outlet duct.

In another embodiment, once the predetermined radon level is realized or a predetermined period of time has lapsed, the radon mitigation assemblyis activated. If activation of the radon mitigation assemblyoccurs while the hybrid water heater systemis idle (i.e., not producing hot water), the evaporator fanis activated. The evaporator fanof the hybrid water heater systemmay pull air from the areabelow the floorand is exhausted into the atmosphere. Thus, the air travels through the inlet duct, into the evaporatorand compressorof the heat pump systemof the hybrid water heater system. The air is then exhausted from the outlet duct, which is in fluid communication with the compressorof the heat pump system. The air is exhausted into the atmospherefrom the outlet endof the outlet duct.

In another embodiment, the hybrid water heater systemis configured to utilize electricity generated by alternative energy (e.g., solar, wind) either exclusively or in combination with electricity provided by the power grid. In this embodiment, the hybrid water heater systemincludes a transfer switch (not shown) that switches between grid power and alternative energy power. In some cases, the hybrid water heater systemmay include a first transfer switch (not shown) that is electrically connected to the grid power, and a second transfer switch (not shown) that is electrically connected to the alternative energy power. The hybrid water heater systemselectively switches between grid power and alternative energy power depending on at least one of the power requirements of the systemsuch as which heat source is running, for example, the heat pump systemor the heating element, the supply capacity of the grid power, the supply capacity of the alternative energy power, and combinations thereof. In this embodiment, the hybrid water heater systemincludes a controller configured to selectively switch between grid power and alternative energy power. In one example, the hybrid water heater systemutilizes only alternative energy power whenever the heat pumpis solely in operation. In other examples, the hybrid water heater systemutilizes both grid power and alternative energy power when both the heat pump systemand the heating elementare in operation. In other examples, the hybrid water heater systemmay utilize only alternative energy power when the heat pumpand the heating elementare in operation. It should be understood, however, that although the hybrid water heater systemis described, water heaters including only the heat pump system may also be configured to utilize electricity generated by alternative energy (e.g., solar) in addition to electricity provided by the power grid. Therefore, discussion of the hybrid water heater systemalso includes water heaters with only a heat pump system, unless expressly stated otherwise.

In another embodiment, the operational mode of the hybrid water heater systemmay be selected based on the input voltage. The desired heating capacity of the hybrid water heater systemmay be selected based on the input voltage.illustrates a graph showing the heating capacity of the hybrid water heater systembased on the changes of the input voltage, where the heating capacity (W) is depicted along the Y-axis and the input voltage (V) is depicted along the X-axis. As shown, as the input voltage decreases, the heating capacity of the heating elementreduces, as shown by the angled line (larger bullet points). In contrast, the heating capacity of the heat pump systemis relatively constant across the input voltage range of the hybrid water heater system. Identifying the heating capacity versus the input voltage may be beneficial in selecting the operational mode, which may include, for example, whether to operate the heat pump system, the heating element, or both the heat pump systemand the heating element. It should be understood that different hybrid water heater systemsmay produce a variation of the graph shown in. Therefore,is not intended to be limiting but merely provides context to the operational mode selection described herein.

In some instances, for example when the heating elementis selected as the heat source and the voltage is lower than a threshold voltage, the hybrid water heater systemwill switch to the heat pump systemas the heating source since it has more heating capacity. In some embodiments, the hybrid water heater systemmay actively estimate the heating capacities of the heat pump systemand the heating elementand switch to the heat pump systemwhen the heating capacity of the heating elementis equal to or less than the heating capacity of the heat pump system.

is an illustration of the heating capacity based on the input voltage of an exemplary hybrid water heater system.

It should be understood that one or more of the features described herein may be combined for use within the hybrid water heater system.