THERMAL SYSTEM

Abstract

A thermal system including a thermal source configured to heat a thermal transfer fluid, first piping configured to convey the heated thermal transfer fluid from the thermal source, and second piping configured to return at least a portion of the thermal transfer fluid to the thermal source to be reheated. The system includes a thermal battery comprising at least two thermal storage tanks, a hot water source, and a pumping loop connected between the thermal battery and the hot water source to circulate at least a portion of the thermal transfer fluid between the thermal battery and the hot water source. The pumping loop includes a reverse return piping configuration connected to the at least two thermal storage tanks. The first piping and the second piping are connected to the pumping loop and the first piping is configured to convey the heated thermal transfer fluid to the pumping loop.

Description

TECHNICAL FIELD

The present disclosure generally relates to thermal systems and configurations to supply domestic hot water.

BACKGROUND

Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted being prior art by inclusion in this section.

A domestic hot water system may be used to provide potable hot water for appliances within a home including kitchen sinks, dishwashers, bathroom sinks and tubs and other appliances. Domestic hot water may have a temperature between 120° F. and 140° F. Domestic hot water may be heated with natural gas, electric resistance, or a heat pump. Domestic hot water may also be generated on demand by an instantaneous indirect coil tank water heater.

In a commercial building, domestic hot water may be generated by a commercial boiler. A commercial boiler may be a pressurized system which burns combustible fuel or electricity to heat potable water.

SUMMARY

Existing challenges associated with the foregoing, as well as other challenges, are overcome by the presently disclosed to thermal systems and configurations to supply domestic hot water.

One embodiment of the present disclosure is a thermal system including a thermal source configured to heat a thermal transfer fluid. The thermal system includes first piping configured to convey the heated thermal transfer fluid from the thermal source and second piping configured to return at least a portion of the thermal transfer fluid to the thermal source to be reheated. The system includes a thermal battery comprising at least two thermal storage tanks and a hot water source. The system includes a pumping loop connected between the thermal battery and the hot water source to circulate at least a portion of the thermal transfer fluid between the thermal battery and the hot water source. The pumping loop includes a reverse return piping configuration connected to the at least two thermal storage tanks. The first piping and the second piping are connected to the pumping loop and the first piping is configured to convey the heated thermal transfer fluid to the pumping loop.

In aspects, the thermal source is an air-to-water hydronic unit.

In aspects, the hot water source includes at least two hot water generators, and the system further comprises a second reverse return piping configuration connected to the at least two hot water generators.

In aspects, the second piping includes at least one pump.

In aspects, the pumping loop includes at least one pump.

In aspects, the thermal transfer fluid is gray water.

In aspects, the thermal storage tanks include a thermal storage material, and the thermal storage material is gray water.

Another embodiment of the present disclosure includes a method of installing a thermal system. The method includes connecting first piping to a thermal source configured to heat a thermal transfer fluid. The first piping is configured to convey the heated thermal transfer fluid from the thermal source. The method includes connecting second piping to the thermal source. The second piping is configured to return at least a portion of the thermal transfer fluid to the thermal source to be reheated. The method includes forming a pumping loop connected between a hot water source and a thermal battery. The thermal battery includes at least two thermal storage tanks. The pumping loop is configured to circulate at least a portion of the thermal transfer fluid between the thermal battery and the hot water source. Forming the pumping loop includes forming a reverse return piping configuration connected to the at least two thermal storage tanks. The method includes connecting the first piping to the pumping loop to convey the heated thermal transfer fluid to the pumping loop and connecting the second piping to the pumping loop.

In aspects, the hot water source includes at least two hot water generators and forming the pumping loop comprises forming a second reverse return piping configuration connected to the at least two hot water generators.

In aspects, forming the pumping loop comprises connecting at least one pump within the pumping loop.

Another embodiment of the present disclosure is a method of generating hot water. The method includes heating a thermal transfer fluid with a thermal source. The method includes conveying the heated thermal transfer fluid to a pumping loop from the heat source by first piping, circulating at least a portion of the thermal transfer fluid in the pumping loop between a thermal battery and a hot water source, and returning, by second piping, at least a portion of the thermal transfer fluid to the thermal source to be reheated. The method includes receiving cold water at the hot water source and heating the cold water by the hot water source based on the thermal transfer fluid to generate the hot water. The thermal battery includes at least two thermal storage tanks that are piped with a reverse return piping configuration.

In aspects, the cold water is domestic cold water, and the hot water generated is domestic hot water with a temperature between 120° F. and 140° F.

The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description and appended claims.

BRIEF DESCRIPTION OF THE FIGURED

The foregoing and other features of this disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only several embodiments in accordance with the disclosure and are, therefore, not to be considered limiting of its scope, the disclosure will be described with additional specificity and detail through use of the accompanying drawings, in which:

FIG. 1 is an illustration of a thermal system to supply domestic hot water in accordance with the present disclosure;

FIG. 2 is an illustration of a primary pumping loop of a thermal system to supply domestic hot water in accordance with the present disclosure;

FIG. 3 is an illustration of a secondary pumping loop of a thermal system to supply domestic hot water in accordance with the present disclosure;

FIG. 4 is an illustration of a cold water supply to hot water supply piping configuration of a thermal system to supply domestic hot water in accordance with the present disclosure;

FIG. 5 is a flow diagram of an example method of installing a thermal system in accordance with the present disclosure; and

FIG. 6 is a flow diagram of an example method of generating domestic hot water in accordance with the present disclosure.

DETAILED DESCRIPTION

In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the Figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well as the singular forms, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof.

The terms “approximately” and “about” may be used to mean within ±20% of a target value in some embodiments, within ±10% of a target value in some embodiments, within ±5% of a target value in some embodiments, and yet within ±2% of a target value in some embodiments. The terms “approximately” and “about” may include the target value.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one having ordinary skill in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

In describing the present disclosure, it will be understood that a number of systems, methodologies, techniques and steps are disclosed. Each of these has individual benefit and each can also be used in conjunction with one or more, or in some cases all, of the other disclosed techniques. Accordingly, for the sake of clarity, this description will refrain from repeating every possible combination of the individual steps in an unnecessary fashion.

Nevertheless, the specification and claims should be read with the understanding that such combinations are entirely within the scope of the disclosure and the claims.

Novel systems and methods for generating hot water are described herein. The present disclosure includes a method for generating hot water that includes heating a thermal transfer fluid with a thermal source. The heated thermal transfer fluid is conveyed to a pumping loop from the heat source by first piping. At least a portion of the thermal transfer fluid is circulated in the pumping loop between a thermal battery and a hot water source. The thermal transfer fluid provides thermal energy to the thermal battery and the hot water source. At least a portion of the thermal transfer fluid is return, by second piping, to the thermal source to be reheated. The hot water source receives cold water from a cold water supply and heats the cold water based on the thermal transfer fluid to generate the hot water. The thermal battery includes at least two thermal storage tanks that are piped with a first reverse return piping configuration.

FIG. 1 is an illustration of a thermal system to supply domestic hot water in accordance with the present disclosure and arranged in accordance with at least some embodiments described herein. Thermal system 100 may include thermal source 10, a thermal battery 20, and a hot water source 30. Thermal source 10, thermal battery 20, and hot water source 30 may be interconnected with piping 40 containing a thermal transfer fluid 50. Piping 40 may include piping 40a and piping 40b. Piping 40a may have a diameter smaller than piping 40b based on thermal system 100 requirements. In an embodiment, piping 40a may have a two inch diameter and piping 40b may have a three inch diameter. Thermal system 100 may further include an expansion tank 45. Expansion tank 45 may prevent excessive pressure within piping 40 of thermal system 100. Expansion tank 45 may be partially filled with air which may prevent a thermal transfer fluid hammer effect within piping 40 as well as absorb excess pressure caused by thermal expansion of thermal transfer fluid 50 within piping 40. Thermal transfer fluid 50 may be any fluid with high heat capacity and thermal conductivity, including gray water, a propylene glycol solution, a refrigerant etc.

Thermal source 10 may include one or more heat devices 15 for heating thermal transfer fluid 50 to a temperature of about 180° F. Thermal device 15 may be any device which can provide heat to thermal transfer fluid 50 such as conventional fossil fuel heaters, a heat pump, an air-to-water hydronic unit, solar panels, geothermal heating, etc. In instances where thermal source 10 includes two or more heat devices 15, heat devices 15 may be connected in parallel by piping 40a. Heat devices 15 may provide heat to thermal transfer fluid 50 within piping 40a. Piping 40a may include piping 62 configured to convey heated thermal transfer fluid 50 from thermal source 10 and heat devices 15. Piping 40a may also include piping 64 which may be configured to return at least a portion of thermal transfer fluid 50 to thermal source 10 and heat devices 15 to be reheated. Each heat device 15 may include a pump 15p which may pump thermal transfer fluid 50 through heat device 15 and piping 62. As described in more detail below, piping 62 and 64 may form a primary pump loop 60 around heat devices 15.

Thermal battery 20 may include at least two thermal storage tanks 25. Thermal storage tanks 25 may be configured so that thermal transfer fluid 50 flows through a tank full of a thermal storage material 25m and thermal transfer fluid 50 may provide thermal energy to thermal storage material 25m. Thermal storage tanks 25 may store thermal energy within thermal storage material 25m as sensible thermal energy storage. Thermal storage material 25m may be water, such as gray or non-potable water, or any material with high heat storage capacity, high thermal diffusivity, and high thermal effusivity. Thermal storage medium 25m may store a relatively large amount of latent heat within thermal storage tanks 25. Thermal storage tanks 25 may be thermal buffer tanks and may provide thermal energy to reduce daily peak thermal requirements of thermal system 100. Thermal storage tanks 25 may also reduce power requirements and thermal capacity requirements of thermal source 10 and thermal devices 15 within thermal system 100. Heat stored in the thermal tanks 25 may provide a portion of thermal energy required of thermal system 100 during peak thermal demand, for example, during the mornings or evenings. Thermal storage tanks 25 may be piped into system 100 with piping 40b in a reverse return configuration so that a total distance of piping 40b to and from each thermal storage tank 25 is equivalent. Piping 40b in a reverse return configuration may balance both temperature and pressure of thermal transfer fluid 50 within piping 40b connected to thermal storage tanks 25 without requiring balancing valves and may ensure that each tank 25 is maintained at a minimum temperature to prevent bacterial growth, such as a temperature above 120° F. to prevent legionella bacterial growth.

Hot water source 30 may include at least two hot water generators 35 for providing domestic hot water at a temperature between 150° F. and 180° F. which is then reduced when passed through a domestic water mixing valve 97 to a temperature between 120° F. and 140° F. Hot water generators 35 may generate domestic hot water 90 from domestic cold water 80. Hot water generators 35 may generate domestic hot water 90 by transferring thermal energy from thermal transfer fluid 50 to domestic cold water 80. Hot water generators 35 may be instantaneous indirect coil tank water heaters which may be configured to supply domestic hot water 90 on demand. In an embodiment, hot water generators 35 may be piped into system 100 with piping 40b in a reverse return configuration so that a total distance of piping 40 to and from each hot water generator 35 is equivalent and temperature and pressure of thermal transfer fluid 50 are balance at hot water generator 35 without requiring balancing valves.

Piping 40 may be configured in a secondary pumping loop 70 which may connect thermal battery 20 and hot water source 30 with piping 40b. Secondary pumping loop 70 may be configured to circulate at least a portion of thermal transfer fluid 50 between thermal battery 20 and hot water source 30. Secondary pumping loop 70 may include pumps 55 and expansion tank 45 within secondary pumping loop 70. Secondary pumping loop 70 may be connected to primary pumping loop 60 at point 105 and point 110. Primary pumping loop 60 may supply thermal energy within thermal transfer fluid 50 to secondary pumping loop 70 at point 110 and secondary pumping loop 70 may return at least a portion of thermal transfer fluid 50 to primary pumping loop 60 at point 105 to be reheated by thermal source 10. Thermal transfer fluid 50 from primary pumping loop 60 may provide thermal energy to thermal battery 20 and hot water source 30. Thermal energy stored within thermal storage material 25m of thermal battery 20 may also provide thermal energy to thermal transfer fluid 50 and hot water source 30.

Thermal system 100 may include temperature sensors 75 which may be located within a core of each thermal storage tank 25, at point 110 where thermal transfer fluid 50 from primary pumping loop 60 enters into secondary pumping loop 70, and at point 105 where thermal transfer fluid 50 returns from secondary pumping loop 70 to primary pumping loop 60. Each temperature sensor 75 may be dedicated to an individual refrigerant to water exchanger and may increase modulation ability beyond the inclusion of invertor compressors which may be built into the heads and may allow for additional equipment operation relative to outdoor condensers in a split refrigerant system configuration.

FIG. 2 is an illustration of a primary pumping loop of a thermal system to supply domestic hot water in accordance with the present disclosure and arranged in accordance with at least some embodiments described herein. Those components in FIG. 2 that are labeled identically to components of FIG. 1 will not be described again for the purposes of brevity.

As previously described, piping 40a may form a primary pump loop 60 around connected heat devices 15. Primary pump loop 60 may convey thermal transfer fluid 50 from thermal source 10 and heat devices 15 to 110. Piping 64 may convey at least a portion of thermal transfer fluid 50 from point 105 to thermal source 10 and heat devices 15 to be reheated. Piping 64 may include a pump 15p for each heat device 15, and each pump 15p may pump thermal transfer fluid 50 through at least some of piping 64 to a respective heat device 15 and subsequently through piping 62. Primary pump loop 60 may convey at least a portion of thermal transfer fluid 50 from 105 through thermal source 10 and heat devices 15 to point 110. Heat devices 15 may provide thermal energy to heat thermal transfer fluid 50 to a temperature of about 180° F.

FIG. 3 is an illustration of a secondary pumping loop of a thermal system to supply domestic hot water in accordance with the present disclosure, arranged in accordance with at least some embodiments described herein. Those components in FIG. 3 that are labeled identically to components of FIG. 1-2 will not be described again for the purposes of brevity.

Secondary pumping loop 70 may include piping 40 which connects thermal battery 20 hot water source 30 and pumps 55. Secondary pumping loop 70 may be configured to pump and circulate at least a portion of thermal transfer fluid 50 between thermal battery 20 and hot water source 30. Secondary pumping loop 70 may be connected to primary pumping loop 60 at point 105 and point 110 of piping 40. Primary pumping loop 60 may supply thermal energy within thermal transfer fluid 50 to secondary pumping loop 70 at point 110 and secondary pumping loop 70 may return at least a portion of thermal transfer fluid 50 to primary pumping loop 60 and thermal source 10 to be reheated at point 105. Thermal transfer fluid 50 from primary pumping loop 60 may provide thermal energy to be stored within thermal storage material 25m of thermal battery 20 and for hot water source 30 to heat water. Thermal energy stored within thermal storage material 25m of thermal battery 20 may also provide thermal energy to thermal transfer fluid 50 and hot water source 30 to heat water. Thermal energy from thermal transfer fluid 50 may be utilized by one or more hot water generators 35 of hot water source 30 to heat domestic cold water 80 and generate domestic hot water 90.

FIG. 4 is an illustration of a cold water supply to hot water supply piping configuration of a thermal system to supply domestic hot water in accordance with the present disclosure, arranged in accordance with at least some embodiments described herein. Those components in FIG. 4 that are labeled identically to components of FIG. 1-3 will not be described again for the purposes of brevity.

Hot water source 30 may include at least two hot water generators 35 which may generate domestic hot water at a temperature between 150° F. and 180° F. As shown in FIG. 4, domestic cold water 80 may be fed into a base of at least one hot water generator 35 by domestic cold water piping 85. Domestic cold water 80 entering hot water generator 35 may flow upward through hot water generator 35 and be heated by receiving thermal energy from thermal transfer fluid 50 within hot water generator 35. Domestic hot water 90 may exiting at a top of hot water generator 35 at piping 95 which may be connected to a domestic hot water system of a building or home. A temperature of domestic hot water 90 may be reduced to a temperature between 120° F. and 140° F. by passing through domestic water mixing valve 97.

A system in accordance with the present disclosure may provide a commercial thermal system which can supply domestic hot water with heat pumps as a thermal source. A system in accordance with the present disclosure may utilize air to water heat pumps to charge thermal storage tanks and to provide heat for instantaneous hot water generation and reduce a heat capacity requirement of the air to water heat pumps. A system in accordance with the present disclosure may utilize heat stored in the thermal battery to reduce heating capacity requirements during peak hot water demand times during mornings and evenings. A system in accordance with the present disclosure may balance pressure and temperatures across thermal storage tanks without requiring expensive pressure valves.

FIG. 5 illustrates a flow diagram for an example method of installing a thermal system, arranged in accordance with at least some embodiments presented herein. An example process may include one or more operations, actions, or functions as illustrated by one or more of blocks S2, S4, S6, S8, and/or S10. Although illustrated as discrete blocks, various blocks may be divided into additional blocks, combined into fewer blocks, or eliminated, depending on the desired implementation.

The method may begin at block S2, “Connect first piping to a thermal source configured to heat a thermal transfer fluid, the first piping configured to convey the heated thermal transfer fluid from the thermal source.” At block S2, first piping may be connected to a thermal source. The thermal source may be configured to heat a thermal transfer fluid. The first piping may be configured to convey the heated thermal transfer fluid from the thermal source.

The method may continue from block S2 to block S4, “Connect second piping to the thermal source, the second piping configured to return at least a portion of the thermal transfer fluid to the thermal source to be reheated.” At block S4, second piping may be connected to the thermal source. The second piping may be configured to return at least a portion of the thermal transfer fluid to the thermal source to be reheated.

The method may continue from block S4 to block S6, “Form a pumping loop connected between a hot water source and a thermal battery comprising at least two thermal storage tanks, the pumping loop configured to circulate at least a portion of the thermal transfer fluid between the thermal battery and the hot water source; wherein forming the pumping loop comprises forming a reverse return piping configuration connected to the at least two thermal storage tanks.” At block S6, a pumping loop may be formed between a hot water source and a thermal battery. The thermal battery may include at least two thermal storage tanks. The pumping loop may be configured to circulate at least a portion of the thermal transfer fluid between the thermal battery and the hot water source. Forming the pumping loop may include forming a reverse return piping configuration connected to the at least two thermal storage tanks.

The method may continue from block S6 to block S8, “Connect the first piping to the pumping loop to convey the heated thermal transfer fluid to the pumping loop.” At block S8, the first piping may be connected to the pumping loop to convey the heated thermal transfer fluid to the pumping loop and supply thermal energy to the thermal battery and hot water source.

The method may continue from block S8 to block S10, “Connect the second piping to the pumping loop.” At block S10, the second piping may be connected to the pumping loop so that at least a portion of the thermal transfer fluid may be returned to the thermal source to be reheated.

FIG. 6 is a flow diagram of an example method of generating domestic hot water in accordance with the present disclosure, arranged in accordance with at least some embodiments presented herein.

The method may begin at block S12, “Heat a thermal transfer fluid with a thermal source.” At block S12, a thermal transfer fluid may be heated by a thermal source. The thermal source mat be an air to water heat pump and the thermal transfer fluid may be gray water.

The method may continue from block S12 to block S14, “Convey the heated thermal transfer fluid to a pumping loop from the heat source by first piping.” At block S14, the heated thermal transfer fluid may be conveyed to a pumping loop from the heat source by first piping. The method may continue from block S14 to block S16, “Circulate at least a portion of the thermal transfer fluid in the pumping loop between a thermal battery and a hot water source.” At block S16, at least a portion of the thermal transfer fluid in the pumping loop may be circulated between a thermal battery and a hot water source. The thermal transfer fluid may supply thermal energy to the thermal battery and hot water source.

The method may continue from block S16 to block S18, “Return, by second piping, at least a portion of the thermal transfer fluid to the thermal source to be reheated.” At block S18, at least a portion of the thermal transfer fluid may be returned by second piping to the thermal source. The returned thermal transfer fluid may be reheated by the thermal source.

The method may continue from block S18 to block S20, “Receive cold water at the hot water source.” At block S20, cold water may be received at the hot water source. The cold water may be domestic cold water.

The method may continue from block S20 to block S22, “Heat the cold water by the hot water source based on the thermal transfer fluid to generate the hot water, wherein the thermal battery includes at least two thermal storage tanks that are piped with a first reverse return piping configuration.” At block S22, the cold water may be heated by the hot water source. The hot water source may heat the cold water based on thermal energy from the thermal transfer fluid to generate the hot water. The thermal battery may include at least two thermal storage tanks and the at least two thermal storage tanks may be piped with a reverse return piping configuration.

It should be understood the foregoing description is only illustrative of the present disclosure. Various alternatives and modifications can be devised by those skilled in the art without departing from the disclosure. Accordingly, the present disclosure is intended to embrace all such alternatives, modifications, and variances. The embodiments described with reference to the attached drawing figures are presented only to demonstrate certain examples of the disclosure. Other elements, steps, methods, and techniques that are insubstantially different from those described above and/or in the appended claims are also intended to be within the scope of the disclosure.

Claims

1. A thermal system comprising: a thermal source configured to heat a thermal transfer fluid;first piping configured to convey the heated thermal transfer fluid from the thermal source;second piping configured to return at least a portion of the thermal transfer fluid to the thermal source to be reheated;a thermal battery comprising at least two thermal storage tanks;a hot water source;a pumping loop connected between the thermal battery and the hot water source to circulate at least a portion of the thermal transfer fluid between the thermal battery and the hot water source, the pumping loop comprising: a reverse return piping configuration connected to the at least two thermal storage tanks, andwherein the first piping and the second piping are connected to the pumping loop, the first piping configured to convey the heated thermal transfer fluid to the pumping loop.

2. The thermal system of claim 1, wherein the thermal source is an air-to-water hydronic unit.

3. The thermal system of claim 1, wherein the hot water source includes at least two hot water generators, and the system further comprises a second reverse return piping configuration connected to the at least two hot water generators.

4. The thermal system of claim 1, wherein the second piping includes at least one pump.

5. The thermal system of claim 1, wherein the pumping loop includes at least one pump.

6. The thermal system of claim 1, wherein the thermal transfer fluid is gray water.

7. The thermal system of claim 1, wherein the thermal storage tanks include a thermal storage material, and the thermal storage material is gray water.

8. A method of installing a thermal system, the method comprising: connecting first piping to a thermal source configured to heat a thermal transfer fluid, the first piping configured to convey the heated thermal transfer fluid from the thermal source;connecting second piping to the thermal source, the second piping configured to return at least a portion of the thermal transfer fluid to the thermal source to be reheated;forming a pumping loop connected between a hot water source and a thermal battery comprising at least two thermal storage tanks, the pumping loop configured to circulate at least a portion of the thermal transfer fluid between the thermal battery and the hot water source;

9. The method of claim 8, wherein the thermal source is an air-to-water hydronic unit.

10. The method of claim 8, wherein the hot water source includes at least two hot water generators and forming the pumping loop comprises forming a second reverse return piping configuration connected to the at least two hot water generators.

11. The method of claim 8, wherein the second piping includes at least one pump.

12. The method of claim 8, wherein forming the pumping loop comprises connecting at least one pump within the pumping loop.

13. The method of claim 8, wherein the thermal transfer fluid is gray water.

14. A method of generating hot water, the method comprising: heating a thermal transfer fluid with a thermal source;conveying the heated thermal transfer fluid to a pumping loop from the heat source by first piping;circulating at least a portion of the thermal transfer fluid in the pumping loop between a thermal battery and a hot water source;returning, by second piping, at least a portion of the thermal transfer fluid to the thermal source to be reheated;receiving cold water at the hot water source; andheating the cold water by the hot water source based on the thermal transfer fluid to generate the hot water,wherein the thermal battery includes at least two thermal storage tanks that are piped with a reverse return piping configuration.

15. The method of claim 14, wherein the thermal source is an air-to-water hydronic unit.

16. The method of claim 14, wherein the hot water source includes at least two hot water generators and forming the pumping loop comprises forming a second reverse return piping configuration connected to the at least two hot water generators.

17. The method of claim 14, wherein the second piping includes at least one pump.

18. The method of claim 14, wherein forming the pumping loop comprises connecting at least one pump within the pumping loop.

19. The method of claim 14, wherein the thermal transfer fluid is gray water.

20. The method of claim 14, wherein the cold water is domestic cold water, and the hot water generated is domestic hot water with a temperature between 120° F. and 140° F.