HYBRID WATER HEATER SYSTEM AND METHODS OF USE

Abstract

A hybrid water heater system includes a body which includes a water storage tank. The hybrid water heater system further 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.

Claims

1. A hybrid water heater system comprising: 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; a heating element mounted relative to the body and in fluid and thermal connection with the water storage tank; wherein 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.

2. The hybrid water heater system according to claim 1, wherein based on the desired output, the heat pump system is configured to consume a first input current of a total available current, the first input current being equal to or less than a maximum current rating of the heat pump system.

3. The hybrid water heater system according to claim 2, wherein the heating element is configured to consume a second input current that is equal to or less than the remaining current based on the difference between the total available current and the first input current.

4. The hybrid water heater system according to claim 1, wherein the desired output is heating capacity, and wherein the hybrid water heater system is configured to selectively operate the heat pump system when the heating capacity of the heating element is below the heating capacity of the heat pump system at a predetermined input voltage.

5. A water heater system comprising: 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; wherein the water heater system is configured to selectively activate the heat pump system based on a desired output, and wherein the desired output is selected from the list comprising water temperature, system efficiency, decibel level, time for water usage, and combinations thereof.

6. The water heater system according to claim 5 further comprising a heating element mounted relative to the body and in fluid and thermal connection with the water storage tank, wherein the water heater system is configured to selectively activate the heating element or the heat pump system and the heating element based on the desired output.

7. The water heater system according to claim 5, wherein the system is configured to estimate hot water usage over a period of time and selectively activate the heat pump system to heat water within the storage tank prior to the expected usage of the water based on the tracked hot water usage.

8. The water heater system according to claim 6, wherein the system is configured to estimate hot water usage over a period of time and selectively activate at least one of the heat pump system or the heating element to heat water within the storage tank prior to the expected usage of the water based on the tracked hot water usage.

9. The water heater system according to claim 5, wherein the heat pump system further comprises an evaporator and a compressor, wherein the evaporator further comprises an evaporator fan, and wherein the speed of the evaporator fan, the speed of the compressor, or the speed of the evaporator fan and the speed of the compressor are adjusted to reduce the decibel level output of the water heater system during operation.

10. The water heater system according to claim 9, wherein the heat pump system is configured to adjust the speed of the evaporator fan before adjusting the speed of the compressor.

11. The water heater system according to claim 5, wherein the water heater system is configured to operate on grid power, alternative energy, or grid power and alternative energy.

12. A method of selecting a power mode of a water heater system, the water heater system includes a body including a water storage tank and a heat pump system mounted relative to the body and in thermal connection with the water storage tank, the method comprising: assessing a temperature of water within the water storage tank over a period of the time to determine which power mode is required; determining whether the temperature is within a predetermined range or outside of the predetermined range, activating a low power mode if the temperature is within the predetermined range, and activating a boost power mode if the temperature is below the predetermined range.

13. The method according to claim 12, wherein activating the low power mode includes only activating the heat pump system.

14. The method according to claim 12, wherein the water heater system also includes a heating element mounted relative to the body and in fluid and thermal connection with the water storage tank, wherein activating the boost power mode includes activating the heat pump system and the heating element.

15. A method of applying pattern learning to a water heater system, the water heater system includes a body including a water storage tank and a heat pump system mounted relative to the body and in thermal connection with the water storage tank, the method comprising: estimating water usage of the water heater system, such as hot water usage, power usage, and tank temperature at predetermined increments to identify patterns; and operating the water heater system beginning a period of time before the identified pattern.

16. The method according to claim 15, wherein the water heater system further comprises a heating element mounted relative to the body and in fluid and thermal connection with the water storage tank, and wherein operating the water heater system in a boost power mode includes activating the heat pump system and the heating element.

17. The method according to claim 15, wherein operating the water heater system further comprises operating the hybrid water heater system in a low power mode.

18. The method according to claim 17 further comprising operating the water heater system in one of a boost power mode and the low power mode based on sensed system parameters.

19. The method according to claim 15 further comprising: estimating a potential for a request for increased water usage based on the identified pattern; and operating the water heater system in response to the estimated increased water usage.

20. The method according to claim 19, wherein operating the water heater system further comprises operating the water heater system in a low power mode prior to the estimated increased water usage and operating the water heater system further comprises operating the water heater system in a boost power mode in response to the estimated timing of increased water usage.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Features and aspects of embodiments are described below with reference to the accompanying drawings, in which elements are not necessarily depicted to scale. Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

[0018] Exemplary embodiments of the present disclosure are further described with reference to the appended figures. It is to be noted that the various features, steps and combinations of features/steps described below and illustrated in the figures can be arranged and organized differently to result in embodiments which are still within the scope of the present disclosure.

[0019] To assist those of ordinary skill in the art in making and using the disclosed assemblies and systems, reference is made to the appended figures, wherein:

[0020] FIG. 1 depicts a side view of a hybrid water heater system, according to the present disclosure;

[0021] FIG. 2 depicts a cross-sectional side view of the hybrid water heater system of FIG. 1, according to the present disclosure;

[0022] FIG. 3A illustrates a graph of water temperature within a tank of the hybrid water heater system of FIGS. 1 and 2 at different compressor speeds during a First Hour Rating test, where the temperature ( C.) is depicted along the Y-axis and the timing (seconds) is depicted along the X-axis;

[0023] FIG. 3B illustrates a graph of total heating capacity of the hybrid water heater system of FIGS. 1 and 2 at different compressor speeds during a First Hour Rating test, where the power (watts) is depicted along the Y-axis and the timing (seconds) is depicted along the X-axis;

[0024] FIG. 3C illustrates a graph of upper element power of the hybrid water heater system of FIGS. 1 and 2 at different compressor speeds during a First Hour Rating test, where the power (watts) is depicted along the Y-axis and the timing (seconds) is depicted along the X-axis;

[0025] FIG. 3D illustrates a graph of compressor power of the hybrid water heater system of FIGS. 1 and 2 at different compressor speeds during a First Hour Rating test, where the power (watts) is depicted along the Y-axis and the timing (seconds) is depicted along the X-axis;

[0026] FIG. 4A illustrates a graph of an exemplary water usage profile, 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;

[0027] FIG. 4B illustrates a graph of the effect of pre-heating the water within the hybrid water heater system of FIGS. 1 and 2, where the tank temperature ( C.) is depicted along the Y-axis and the water usage time stamp (hr.) is depicted along the X-axis;

[0028] FIG. 5 illustrates a flow chart of the hybrid water heater system of FIGS. 1 and 2 selecting a power mode based on the temperature of water within a tank versus time;

[0029] FIG. 6 illustrates a side view of a radon mitigation assembly utilizing the hybrid water heater system of FIGS. 1 and 2; and

[0030] FIG. 7 illustrates a graph of the heating capacity of the hybrid water heater system of FIGS. 1 and 2 based on 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.

DETAILED DESCRIPTION OF THE DISCLOSURE

[0031] 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 FIGS. 1 and 2, a hybrid water heater system 10 includes a body 12, a heat pump system 14 and a heating element 16. The body 12 of the hybrid water heater system 10 may be at least partially a storage tank 18 for holding a fluid (e.g., water). The heat pump system 14 may be in thermal connection with the storage tank 18 of the hybrid water heater system 10. For example, the heat pump system 14 may be in thermal connection with water within the storage tank 18 of the hybrid water heater system 10. The heating element 16 may be in thermal and fluid connection with the storage tank 18 of the hybrid water heater system 10. For example, the heating element 16 may be in fluid and thermal connection with water within the storage tank 18 of the hybrid water heater system 10. Although depicted as a combined system, it should be understood that the heat pump system 14 and the heating element 16 may 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.

[0032] The hybrid water heater system 10 includes a water inlet 20 and a water outlet 22. The water inlet 20 and the water outlet 22 may be fluidly connected to the storage tank 18 of the body 12 of the hybrid water heater system 10. The water inlet 20 typically receives water that is colder than the water released by the water outlet 22. In some instances, the water inlet 20 is fluidly connected to a water source (e.g., municipal water, wells, lakes/ponds, streams) and the water outlet 22 is fluidly connected to a fixture, device, appliance, or the like. The hybrid water heater system 10 may include at least one temperature monitoring apparatus (not shown) positioned to measure the water temperature in close proximity to the water outlet 22.

[0033] The heat pump system 14 includes an air inlet 24 and an air outlet 26. The air inlet 24 draws air from the room (not shown) where the hybrid water heater system 10 is installed and/or from an area outside the room (e.g., another room, outside the building), and the air outlet 26 expels air into the room (not shown) where the hybrid water heater system 10 is installed and/or into an area outside the room (e.g., another room, outside the building). The air inlet 24 and the air outlet 26 are fluidly connected to an evaporator 28 and a compressor 30. The evaporator 28 and the compressor 30 are fluidly connected with each other by a pipe 32, thereby creating the closed-loop heat pump system 14. The evaporator 28 may include an evaporator fan 31. A fluid (e.g., a refrigerant) travels through the evaporator 28 and the compressor 30 by way of the pipe 32. The pipe 32 may include additional coiling 34 positioned relative to the storage tank 18. For example, the coiling 34 of the pipe 32 may be in close proximity to the water inlet 20. An expansion valve 36 may be in fluid connection with the pipe 32.

[0034] In operation and as depicted in FIG. 2, heat from the air at the air inlet 24 is absorbed by the refrigerant within the evaporator 28. The evaporator fan 31 pulls the air from outside of the hybrid water heater system 10 into the evaporator 28. The refrigerant is delivered to the compressor 30 as a low-pressure cool gas, as indicated by the arrows in relation to the pipe 32. The air travels through the heat pump system and is expelled through the air outlet 26. The air temperature at the air outlet 26 is colder than the air temperature at the air inlet 24. The refrigerant exiting the compressor 30 is a high-pressure hot gas which travels within the pipe 32 to the coiling 34. Within the coiling 34, the refrigerant becomes a high-pressure warm liquid and heats the water within the storage tank 18. The refrigerant within the pipe 32 travels through the expansion valve 36 and into the evaporator 28 as a low-pressure cold liquid. The process utilized by the heat pump system 14 is repeated, as necessary. Positioned relative to and in fluid connection with the water within the storage tank 18, the heating element 16 may heat the water before it exits through the water outlet 22. As depicted, the heating element 16 is in close proximity to the water outlet 22 such that it supplements the heating process from the heat pump system. However, it should be understood that the heating element 16 may be positioned at any location within the storage tank 18, such as, any location along the height of the storage tank 18.

[0035] In some embodiments, the operating parameters of the hybrid water heater system 10 may be optimized to fully utilize the input current rating of the hybrid water heater system 10. For example, adjusting the operating parameters of the heat pump system 14 and/or the heating element 16 such that the sum of the currents of the heat pump system 14 and the heating element 16 are about equal to the current rating of the hybrid water heater system 10. The operating parameters of the hybrid water heater system 10 may be controlled by at least one pulse width modulation (PWM) controller. In some instances, less current may be allocated to the heat pump system 14 versus the heating element 16. In other instances, the current allocated to the heat pump system 14 and the heating element 16 may be about equal Allocating more current to the heat pump system 14 may increase the overall efficiency of the hybrid water heater system 10 and may increase the temperature of the water at the water outlet 22 of the hybrid water heater system 10 compared to a hybrid water heater system that allocates less current to the heat pump system 14

[0036] In one embodiment, current may be allocated to the heat pump system 14 based, in part, on the max current rating of the heat pump system 14. For example, current may be allocated to the heat pump system 14 that 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 30. The desired speed of the compressor 30 may be equal to or less than the max speed of the compressor 30. The remaining current in excess of the amount allocated to the heat pump system 14 is allocated to the heating element 16.

[0037] FIGS. 3A-3D illustrate the results of operating the hybrid water heater system 10 at different compressor speeds, including 3,000 revolutions per minute (RPM), 4,200 RPM, and 5,500 RPM.

[0038] FIG. 3A illustrates the temperature of the water within the storage tank 18 near the water outlet 22 where the hybrid water heater system 10 is operated at different compressor speeds, including 3,000 RPM, 4,200 RPM, and 5,500 RPM. FIG. 3A depicts the temperature ( C.) along the Y-axis and the timing (seconds) along the X-axis. The hybrid water heat system 10 operating at 5,500 RPM produced a lower temperature drop beginning before the 3,500 second mark versus the hybrid water heater system 10 operating at 3,000 and 4,200 RPM.

[0039] FIG. 3B illustrates the total heating capacity of the hybrid water heater system 10 operating 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 10, including the current of the heat pump system and the heating element is the same for each of the compressor speeds. FIG. 3B 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 system 10 is the same for each of the compressor speeds, but the higher the compressor speed, the more heating capacity that is produced.

[0040] FIG. 3C 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. FIG. 3C illustrates that the upper element power is lower at higher speeds.

[0041] FIG. 3D 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. FIG. 3D illustrates that the compressor power is higher at higher speeds.

[0042] As explained above, the sum of the input currents to the hybrid water heater system 10, including the current to the heat pump system 14 and the heating element 16, is the same for all speeds of the compressor 30. FIGS. 3B, 3C, and 3D together depict that by allocating more current to the heat pump system 14 (i.e., the compressor runs at a higher speed, for example 5,500 RPM), the hybrid water heater system 10 achieves a higher total heating capacity as shown specifically in FIG. 3B.

[0043] Table 1, shown below, compares the number of gallons of hot water the hybrid water heater system 10 can 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.

TABLE-US-00001 TABLE 1 First Hour Rating (Gallons) Compressor RPM of Maximize Current of Fixed UE Power of the Hybrid Water the Hybrid Water the Hybrid Water Heater System Heater System Heater System 3,000 67.76 65.75 4,200 69.52 68.51 5,500 71.78 71.52

[0044] In some embodiments, the hybrid water heater system 10 may include pattern learning capabilities. In a non-limiting example, the hybrid water heater system 10 includes 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 system 10 is described, water heaters including only the heat pump system may also include pattern learning capabilities. Therefore, discussion of the hybrid water heater system 10 also includes water heaters with only a heat pump system, unless expressly stated otherwise. The hybrid water heater system 10 may 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 system 10 may 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 system 10 may 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 system 14 and/or the heating element 16 may begin heating the water within the storage tank 18 of the hybrid water heater system 10 a period of time before the hot water is required (e.g., a time of a given day).

[0045] Referring to FIGS. 4A and 4B, the hybrid water heater system 10 prepares a water usage profile at adjustable increments per day and based on that information, pre-heats the water within the storage tank 18 to ensure hot water is available at a given time based on the water usage profile. FIG. 4A illustrates a bar graph showing an exemplary water usage profile over a period of 6.5 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. FIG. 4B illustrates a graph showing the effect of pre-heating the water within the storage tank 18, 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 system 10 utilizing the pre-heat features maintains a higher water temperature within the storage tank 18 versus typical water heater systems.

[0046] The hybrid water heater system 10 may 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 system 10 is 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 system 10 also includes water heaters with only a heat pump system, unless expressly stated otherwise. The hybrid water heater system 10 may select which power mode is required based on the hot water requirements. The hybrid water heater system 10 may 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 18. 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 system 10 may determine that the water can be heated using the low power mode.

[0047] In some examples, the hybrid water heater system 10 may utilize the low power mode and begin heating the water within the storage tank 18 with enough time to ensure hot water is available at a desired time. In some examples, the hybrid water heater system 10 may utilize the boost power mode and begin heating the water within the storage tank 18 with enough time to ensure hot water is available at a desired time. In other examples, the hybrid water heater system 10 may utilize the low power mode to begin heating the water within the storage tank 18 to 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 system 10 may utilize the boost power mode to heat water within the storage tank 18 to accommodate an immediate hot water requirement.

[0048] In some instances, the low power mode of the hybrid water heater system 10 relates to using predominantly the heat pump system 14. In some instances, the boost power mode of the hybrid water heater system 10 relates to using both the heat pump system 14 and the heating element 16.

[0049] Referring to FIG. 5, the hybrid water heater system 10 may 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 102. Reference number 104 indicates 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 106. If the rate of change in temperature is outside the predetermined range, the boost power mode may be utilized, as indicated by reference number 106. For example, the low power mode may utilize only the heat pump system 14 of the hybrid water heater system 10 to heat the water within the storage tank 18. For example, the boost power mode may utilize both the heat pump system 14 and the heating element 16 of the hybrid water heater system 10 to heat the water within the storage tank 18.

[0050] In some embodiments, the noise produced by the hybrid water heater system 10 may be optimized to a desired decibel level. The operation of at least one component of the hybrid water heater system 10 may be adjusted to decrease or increase the decibel output from the system 10 while maintaining a desired heating performance (e.g., hot water capacity, system efficiency, water temperature). In some instances, the hybrid water heater system 10 may adjust at least one component to decrease or increase the decibel output from the system 10 to be consistent with the ambient noise surrounding the hybrid water heater system 10.

[0051] The decibel level output of the hybrid water heater system 10 may be automatically adjusted as the decibel level within the room changes. In operation, the hybrid water heater system 10 may monitor the noise within the room for a predetermined period of time before adjusting the at least one component of the system 10 to decrease or increase the decibel level output of the system 10. 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 system 10 may include preset decibel levels that may be selectable by a user based on the user's desired decibel level output of the system 10. The selectable preset decibel levels (not shown) may also provide the user with comparable efficiency settings of the hybrid water heater system 10. Therefore, the user can select a preset decibel level that also ensures their hot water needs are maintained based on the efficiency of the system 10 at the selected decibel level.

[0052] To adjust the decibel level output of the hybrid water heater system 10, at least one component of the system 10 may be adjusted. For example, the speed of the evaporator fan 31 may be reduced to decrease the decibel level of the hybrid water heater system 10. In other instances, the speed of the compressor may be reduced to decrease the decibel level of the hybrid water heater system 10. In some instances, the speed of the evaporator fan 31 and the speed of the compressor may be reduced. The speed of the evaporator fan 31 may be reduced before the speed of the compressor.

[0053] Table 2, provided below, depicts the effect fan speed has on the water heating performance of the hybrid water heater system 10. As shown in the table, the performance of the hybrid water heater system 10 can maintain, or nearly maintain, a consistent tank water temperature at various speeds of the compressor 30 and the evaporator fan 31. In some cases, reducing the speed of evaporator fan 31 may also produce a lower decibel level output of the hybrid water heater system 10. Thus, in some instances, and as shown below in Table 2, decreasing the evaporator fan 31 may reduce the noise output of the hybrid water heater system 10 with minimal or no impact on the heating performance (i.e., C/minute) of the hybrid water heater system 10. For example, when the speed of the compressor 30 is maintained at 3,000 RPM, and the speed of the evaporator fan 31 is 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 fan 31 may 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 10.

TABLE-US-00002 TABLE 2 Compressor Temperature Speed of Water in Evaporator Fan Speed (RPM) (RPM) Tank ( C.) 1,400 1,700 1,900 2,400 43-50 0.067 0.058 0.073 3,000 43-50 0.080 0.084 0.085 4,000 38-42 0.112 0.118 0.111

[0054] In another embodiment, the hybrid water heater system 10 may be configured to remove radon from at least the room where the system 10 is installed. Referring to FIG. 6, a radon mitigation assembly 200 includes the hybrid water heater system 10 which is positioned within a room 202. The radon mitigation assembly 200 includes an inlet duct 206 that extends through the floor 204 of the room 202 such that an inlet end 208 of the inlet duct 206 is open to the area 210 below the floor 204 (e.g., ground, soil). The radon mitigation assembly 200 includes an outlet duct 212 that extends through an exterior boundary (e.g., roof 214, exterior wall 216) such that an outlet end 218 of the outlet duct 212 is open to the atmosphere 220 outside of the room 202. The radon mitigation system 200 is in fluid communication with the heat pump system 14 of the hybrid water heater system 10. The compartment of the heat pump system 14 of the hybrid water heater system 10 may include additional sealing to enclose the heat pump system 14 such that air leakage from the compartment is reduced. In some cases, air leakage from the compartment of the heat pump system 14 may be significantly reduced almost to, or at the point of, elimination.

[0055] In operation, the radon mitigation assembly 200 is 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.

[0056] In one embodiment, once the predetermined radon level is realized or a predetermined period of time has lapsed, the radon mitigation assembly 200 is activated. If activation of the radon mitigation assembly 200 occurs while the hybrid water heater system 10 is producing hot water and/or has been requested to produce hot water, the speed of the evaporator fan 31 of the hybrid water heater system 10 is increased. The evaporator fan 31 may pull air from the environment around the hybrid water heater system 10, as done in the normal course of operation. Thus, the air travels into the evaporator 28, through the evaporator fan 31, and into the compressor 30 of the heat pump system 14 of the hybrid water heater system 10. The air is then exhausted from the outlet duct 212, which is in fluid communication with the compressor 30 of the heat pump system 14. The air is exhausted into the atmosphere 220 from the outlet end 218 of the outlet duct 212.

[0057] In another embodiment, once the predetermined radon level is realized or a predetermined period of time has lapsed, the radon mitigation assembly 200 is activated. If activation of the radon mitigation assembly 200 occurs while the hybrid water heater system 10 is idle (i.e., not producing hot water), the evaporator fan 31 is activated. The evaporator fan 31 of the hybrid water heater system 10 may pull air from the area 210 below the floor 204 and is exhausted into the atmosphere 220. Thus, the air travels through the inlet duct 206, into the evaporator 28 and compressor 30 of the heat pump system 14 of the hybrid water heater system 10. The air is then exhausted from the outlet duct 212, which is in fluid communication with the compressor 30 of the heat pump system 14. The air is exhausted into the atmosphere 220 from the outlet end 218 of the outlet duct 212.

[0058] In another embodiment, the hybrid water heater system 10 is 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 system 10 includes a transfer switch (not shown) that switches between grid power and alternative energy power. In some cases, the hybrid water heater system 10 may 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 system 10 selectively switches between grid power and alternative energy power depending on at least one of the power requirements of the system 10 such as which heat source is running, for example, the heat pump system 14 or the heating element 16, 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 system 10 includes a controller configured to selectively switch between grid power and alternative energy power. In one example, the hybrid water heater system 10 utilizes only alternative energy power whenever the heat pump 14 is solely in operation. In other examples, the hybrid water heater system 10 utilizes both grid power and alternative energy power when both the heat pump system 14 and the heating element 16 are in operation. In other examples, the hybrid water heater system 10 may utilize only alternative energy power when the heat pump 14 and the heating element 16 are in operation. It should be understood, however, that although the hybrid water heater system 10 is 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 system 10 also includes water heaters with only a heat pump system, unless expressly stated otherwise.

[0059] In another embodiment, the operational mode of the hybrid water heater system 10 may be selected based on the input voltage. The desired heating capacity of the hybrid water heater system 10 may be selected based on the input voltage. FIG. 7 illustrates a graph showing the heating capacity of the hybrid water heater system 10 based 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 element 16 reduces, as shown by the angled line (larger bullet points). In contrast, the heating capacity of the heat pump system 14 is relatively constant across the input voltage range of the hybrid water heater system 10. 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 14, the heating element 16, or both the heat pump system 14 and the heating element 16. It should be understood that different hybrid water heater systems 10 may produce a variation of the graph shown in FIG. 7. Therefore, FIG. 7 is not intended to be limiting but merely provides context to the operational mode selection described herein.

[0060] In some instances, for example when the heating element 16 is selected as the heat source and the voltage is lower than a threshold voltage, the hybrid water heater system 10 will switch to the heat pump system 14 as the heating source since it has more heating capacity. In some embodiments, the hybrid water heater system 10 may actively estimate the heating capacities of the heat pump system 14 and the heating element 16 and switch to the heat pump system 14 when the heating capacity of the heating element 16 is equal to or less than the heating capacity of the heat pump system 14.

[0061] FIG. 7 is an illustration of the heating capacity based on the input voltage of an exemplary hybrid water heater system 10.

[0062] It should be understood that one or more of the features described herein may be combined for use within the hybrid water heater system 10.

[0063] The following clauses further define particular aspects and embodiments of the present disclosure.

[0064] Clause 1. A hybrid water heater system including: 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; a heating element mounted relative to the body and in fluid and thermal connection with the water storage tank; wherein 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.

[0065] Clause 2. The hybrid water heater system according to clause 1, wherein based on the desired output, the heat pump system is configured to consume a first input current of a total available current, the first input current being equal to or less than a maximum current rating of the heat pump system.

[0066] Clause 3. The hybrid water heater system according to any of the proceeding clauses, wherein the heating element is configured to consume a second input current that is equal to or less than the remaining current based on the difference between the total available current and the first input current.

[0067] Clause 4. The hybrid water heater system according to any of the proceeding clauses, wherein the desired output is heating capacity, and wherein the hybrid water heater system is configured to selectively operate the heat pump system when the heating capacity of the heating element is below the heating capacity of the heat pump system at a predetermined input voltage.

[0068] Clause 5. A water heater system including: 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; wherein the water heater system is configured to selectively activate the heat pump system based on a desired output, and wherein the desired output is selected from the list including water temperature, system efficiency, decibel level, time for water usage, and combinations thereof.

[0069] Clause 6. The water heater system according to any of the proceeding clauses further including a heating element mounted relative to the body and in fluid and thermal connection with the water storage tank, wherein the water heater system is configured to selectively activate the heating element or the heat pump system and the heating element based on the desired output.

[0070] Clause 7. The water heater system according to any of the proceeding clauses, wherein the system is configured to track hot water usage over a period of time and selectively activate the heat pump system to heat water within the storage tank prior to the expected usage of the water based on the tracked hot water usage.

[0071] Clause 8. The water heater system according to any of the proceeding clauses, wherein the system is configured to track hot water usage over a period of time and selectively activate at least one of the heat pump system or the heating element to heat water within the storage tank prior to the expected usage of the water based on the tracked hot water usage.

[0072] Clause 9. The water heater system according to any of the proceeding clauses, wherein the heat pump system further includes an evaporator positioned in proximity to an inlet of the heat pump system and a compressor positioned in proximity to an outlet of the heat pump system, wherein the evaporator further includes an evaporator fan, and wherein the speed of the evaporator fan, the speed of the compressor, or the speed of the evaporator fan and the speed of the compressor are adjusted to reduce the decibel level output of the water heater system during operation.

[0073] Clause 10. The water heater system according to any of the proceeding clauses, wherein the heat pump system is configured to adjust the speed of the evaporator fan before adjusting the speed of the compressor.

[0074] Clause 11. The water heater system according to any of the proceeding clauses, wherein the water heater system is configured to operate on grid power, alternative energy, or grid power and alternative energy.

[0075] Clause 12. A method of selecting a power mode of a water heater system, the water heater system includes a body including a water storage tank and a heat pump system mounted relative to the body and in thermal connection with the water storage tank, the method including: assessing a temperature of water within the water storage tank over a period of the time to determine which power mode is required; determining whether the temperature is within a predetermined range or outside of the predetermined range, activating a low power mode if the temperature is within the predetermined range, and activating a boost power mode if the temperature is below the predetermined range.

[0076] Clause 13. The method according to any of the proceeding clauses, wherein the low power mode includes only activating the heat pump system.

[0077] Clause 14. The method according to any of the proceeding clauses, wherein the water heater system also includes a heating element mounted relative to the body and in fluid and thermal connection with the water storage tank, wherein activating the boost power mode includes activating the heat pump system and the heating element.

[0078] Clause 15. A method of applying pattern learning to a water heater system, the water heater system includes a body including a water storage tank and a heat pump system mounted relative to the body and in thermal connection with the water storage tank, the method includes tracking water usage of the water heater system, such as hot water usage, power usage, and tank temperature at predetermined increments to identify patterns; and operating the water heater system beginning a period of time before the identified pattern.

[0079] Clause 16. The method according to any of the proceeding clauses, wherein the water heater system further includes a heating element mounted relative to the body and in fluid and thermal connection with the water storage tank, wherein operating the water heater system in a boost power mode includes activating the heat pump system and the heating element.

[0080] Clause 17. The method according to any of the proceeding clauses, wherein operating the water heater system further includes operating the hybrid water heater system in a low power mode.

[0081] Clause 18. The method according to any of the proceeding clauses further including operating the water heater system in one of a boost power mode and the low power mode based on sensed system parameters.

[0082] Clause 19. The method according to any of the proceeding clauses further includes estimating a potential for a request for increased water usage based on the identified pattern; and operating the water heater system in response to the estimated increased water usage.

[0083] Clause 20. The method according to any of the proceeding clauses, wherein operating the water heater system further comprises operating the water heater system in a low power mode prior to the estimated increased water usage and operating the water heater system further comprises operating the water heater system in a boost power mode in response to the estimated timing of increased water usage.

[0084] Clause 21. The water heater system according to any of the proceeding clauses, wherein the water heater system is selectively activated to maintain the decibel level consistent with ambient noise.

[0085] Clause 22. A method of applying water usage pattern learning to a water heater system, 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 including: tracking water usage at predetermined increments to identify instances of increased water usage and reduced water usage; and operating the water heater system to increase the temperature of water within the water storage tank beginning a period of time before an instance of increased water usage.

[0086] While the invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes may be made, and equivalents may be substituted for the elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt the teaching of the invention to particular use, application, manufacturing conditions, use conditions, composition, medium, size, and/or materials without departing from the essential scope and spirit of the invention. Therefore, it is intended that the invention is not limited to the exemplary embodiments and best mode contemplated for carrying out this invention as described herein. Since many modifications, variations, and changes in detail can be made to the described examples, it is intended that all matters in the preceding description and shown in the accompanying figures be interpreted as illustrative and not in a limiting sense.