Integrated Thermal Energy Storage and Heat Pump System for Enhanced Demand Response

Abstract

A thermal management system is disclosed having an integrated thermal energy storage module that is operated in a manner that provides energy-saving demand response. The thermal management system monitors operating conditions, including indoor and outdoor temperatures, a state of charge of the integrated thermal energy storage module, a temperature of the energy storage medium of the integrated thermal energy storage module, and the costs to operate the thermal management system. Based on the operating conditions, the thermal management system optimizes the heating or cooling operations by leveraging the integrated thermal energy storage module when appropriate.

Claims

1. A method for operating a thermal management system having a thermal energy storage module, the method comprising: comparing, with a controller, a temperature of a first environment with a deadband temperature range around a setpoint temperature for the first environment, the first environment being temperature-regulated by the thermal management system; operating, with the controller, in response to the temperature of the first environment being outside of the deadband temperature range, the thermal management system to heat or cool the first environment by transferring thermal energy between (i) the first environment and (ii) a second environment or the thermal energy storage module; and operating, with the controller, in response to the temperature of the first environment being within the deadband temperature range, the thermal management system to store or release thermal energy in the thermal energy storage module by transferring thermal energy between the second environment and the thermal energy storage module.

2. The method according to claim 1, wherein the first environment is an indoors environment and the second environment is an outdoors environment.

3. The method according to claim 1, the operating the thermal management system to heat or cool the first environment further comprising: operating, in response to the temperature of the first environment being less than the deadband temperature range, the thermal management system to heat the first environment by transferring thermal energy to the first environment from the second environment or from the thermal energy storage module; and operating, in response to the temperature of the first environment being greater than the deadband temperature range, the thermal management system to cool the first environment by transferring thermal energy from the first environment to the second environment or to the thermal energy storage module.

4. The method according to claim 3, the operating the thermal management system to heat the first environment further comprising: receiving a state of charge of the thermal energy storage module; operating, in response to the state of charge exceeding a first threshold, the thermal management system to release thermal energy from the thermal energy storage module and heat the first environment by transferring thermal energy from the thermal energy storage module to the first environment; and operating, in response to the state of charge being below the first threshold, the thermal management system to heat the first environment by transferring thermal energy from the second environment to the first environment.

5. The method according to claim 3, the operating the thermal management system to heat the first environment further comprising: receiving a time-of-use rate plan indicating at least one window of time during which a cost of electricity to operate the thermal management system is increased compared to another window of time; operating, during the at least one window of time, the thermal management system to release thermal energy from the thermal energy storage module and heat the first environment by transferring thermal energy from the thermal energy storage module to the first environment; and operating, outside of the at least one window of time, the thermal management system to heat the first environment by transferring thermal energy from the second environment to the first environment.

6. The method according to claim 3, the operating the thermal management system to heat the first environment further comprising: comparing a temperature of a thermal storage medium of the thermal energy storage module with a temperature of the second environment; operating, in response to the temperature of the thermal storage medium being greater than the temperature of the second environment, the thermal management system to release thermal energy from the thermal energy storage module and heat the first environment by transferring thermal energy from the thermal energy storage module to the first environment; and operating, in response to the temperature of the thermal storage medium being less than the temperature of the second environment, the thermal management system to heat the first environment by transferring thermal energy from the second environment to the first environment.

7. The method according to claim 3, the operating the thermal management system to heat the first environment further comprising: comparing an average temperature of the second environment over a predetermined time period with a first threshold temperature; and operating, in response to the average temperature of the second environment being greater than the first threshold temperature, the thermal management system to heat the first environment by transferring thermal energy from the second environment to the first environment.

8. The method according to claim 7, the operating the thermal management system to heat the first environment further comprising: comparing a current temperature of the second environment with a second threshold temperature; and operating, in response to (i) the average temperature of the second environment being greater than the first threshold temperature and (ii) the current temperature being less than the second threshold temperature, the thermal management system to heat the first environment by transferring thermal energy from the second environment to the first environment.

9. The method according to claim 3, the operating the thermal management system to cool the first environment further comprising: receiving a state of charge of the thermal energy storage module; operating, in response to the state of charge being below a second threshold, the thermal management system to store thermal energy in the thermal energy storage module and cool the first environment by transferring thermal energy from the first environment to the thermal energy storage module; and operating, in response to the state of charge exceeding the second threshold, the thermal management system to cool the first environment by transferring thermal energy from the first environment to the second environment.

10. The method according to claim 3, the operating the thermal management system to cool the first environment further comprising: receiving a time-of-use rate plan indicating at least one window of time during which a cost of electricity to operate the thermal management system is increased compared to another window of time; operating, during the at least one window of time, the thermal management system to store thermal energy in the thermal energy storage module and cool the first environment by transferring thermal energy from the first environment to the thermal energy storage module; and operating, outside of the at least one window of time, the thermal management system to cool the first environment by transferring thermal energy from the first environment to the second environment.

11. The method according to claim 3, the operating the thermal management system to cool the first environment further comprising: comparing a temperature of a thermal storage medium of the thermal energy storage module with a temperature of the second environment; operating, in response to the temperature of the thermal storage medium being less than the temperature of the second environment, the thermal management system to store thermal energy in the thermal energy storage module and cool the first environment by transferring thermal energy from the first environment to the thermal energy storage module; and operating, in response to the temperature of the thermal storage medium being less than the temperature of the second environment, the thermal management system to cool the first environment by transferring thermal energy from the first environment to the second environment.

12. The method according to claim 3, the operating the thermal management system to cool the first environment further comprising: comparing an average temperature of the second environment over a predetermined time period with a first threshold temperature; and operating, in response to the average temperature of the second environment being less than the first threshold temperature, the thermal management system to cool the first environment by transferring thermal energy from the first environment to the second environment.

13. The method according to claim 12, the operating the thermal management system to heat the first environment further comprising: comparing a current temperature of the second environment with a second threshold temperature; and operating, in response to (i) the average temperature of the second environment being less than the first threshold temperature and (ii) the current temperature being greater than the second threshold temperature, the thermal management system to cool the first environment by transferring thermal energy from the first environment to the second environment.

14. The method according to claim 1, the operating thermal management system in response to the temperature of the first environment being within the deadband temperature range further comprising: comparing an average temperature of the second environment over a predetermined time period with a first threshold temperature; receiving a state of charge of the thermal energy storage module; and operating, in response to the average temperature of the second environment being less than the first threshold temperature and (ii) the state of charge being below a second threshold, the thermal management system to store thermal energy in the thermal energy storage module by transferring thermal energy from the second environment to the thermal energy storage module.

15. The method according to claim 1, the operating thermal management system in response to the temperature of the first environment being within the deadband temperature range further comprising: comparing an average temperature of the second environment over a predetermined time period with a first threshold temperature; receiving a time-of-use rate plan indicating at least one window of time during which a cost of electricity to operate the thermal management system is increased compared to another window of time; and operating, outside of the at least one window of time, in response to the average temperature of the second environment being less than the first threshold temperature, the thermal management system to store thermal energy in the thermal energy storage module by transferring thermal energy from the second environment to the thermal energy storage module.

16. The method according to claim 1, the operating thermal management system in response to the temperature of the first environment being within the deadband temperature range further comprising: comparing an average temperature of the second environment over a predetermined time period with a first threshold temperature; receiving a state of charge of the thermal energy storage module; and operating, in response to (i) the average temperature of the second environment greater than the first threshold temperature and (ii) the state of charge being greater than a first threshold, the thermal management system to release thermal energy from the thermal energy storage module by transferring thermal energy from the thermal energy storage module to the second environment.

17. The method according to claim 1, the operating thermal management system in response to the temperature of the first environment being within the deadband temperature range further comprising: comparing an average temperature of the second environment over a predetermined time period with a first threshold temperature; receiving a time-of-use rate plan indicating at least one window of time during which a cost of electricity to operate the thermal management system is increased compared to another window of time; and operating, outside of the at least one window of time, in response to the average temperature of the second environment greater than the first threshold temperature, the thermal management system to release thermal energy from the thermal energy storage module by transferring thermal energy from the thermal energy storage module to the second environment.

18. The method according to claim 1, wherein the thermal energy storage module includes a resistive heating element configured to add thermal energy to the thermal energy storage module by heating a thermal storage medium of the thermal energy storage module.

19. The method according to claim 18 further comprising: comparing, with the controller, (i) an energy-efficiency of operating the resistive heating element to store thermal energy in the thermal energy storage module and (ii) an energy-efficiency of operating a compressor to circulate refrigerant through a heat exchanger of the thermal energy storage module to store thermal energy in the thermal energy storage module; and operating, with the controller, the resistive heating element of the thermal energy storage module to store additional thermal energy in the thermal energy storage module by heating the thermal storage medium in response to determining that it is more energy-efficient to operate the resistive heating element to store thermal energy in the thermal energy storage module.

20. The method according to claim 1, wherein the thermal energy storage module includes (i) a first thermal storage medium configured to release thermal energy into the first environment while heating the first environment and (ii) a second thermal storage medium configured to store thermal energy extracted from the first environment while cooling the first environment.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The foregoing aspects and other features of the system and methods are explained in the following description, taken in connection with the accompanying drawings.

[0007] FIG. 1 shows an overview of a workflow for operating a thermal management system having an integrated thermal energy storage module.

[0008] FIG. 2 shows exemplary components of a heat pump system for a building having integrated thermal energy storage.

[0009] FIG. 3 shows a flow diagram for a method for operating a thermal management system, such as the heat pump system, which incorporates thermal energy storage module.

[0010] FIG. 4 shows a flow diagram for a method for selecting a control model for operating a thermal management system.

[0011] FIG. 5A shows a flow diagram for a method for controlling the thermal management system using the primary heating model.

[0012] FIG. 5B shows a flow diagram for a method for controlling the thermal management system using the primary cooling model.

DETAILED DESCRIPTION

[0013] For the purposes of promoting an understanding of the principles of the disclosure, reference will now be made to the embodiments illustrated in the drawings and described in the following written specification. It is understood that no limitation to the scope of the disclosure is thereby intended. It is further understood that the present disclosure includes any alterations and modifications to the illustrated embodiments and includes further applications of the principles of the disclosure as would normally occur to one skilled in the art to which this disclosure pertains.

Overview

[0014] FIG. 1 shows an overview of a workflow for operating a thermal management system having an integrated thermal energy storage module. In the exemplary embodiment of the disclosure, the thermal management system is a heat pump system for heating and cooling a building. However, although the features of the disclosure are primarily described with respect to a heat pump system, it should be appreciated that the thermal management system may similarly comprise an air conditioner for cooling a building, a thermal management system for heating or cooling a motor vehicle, or any other thermal management system that operates using similar principles, such as a refrigerator or freezer.

[0015] Disclosed herein is a method for operating the thermal management system in a manner that optimizes the storage and release of thermal energy from the integrated thermal energy storage module during heating and cooling operations to provide energy-saving demand response. The thermal management system monitors (block 10) operating conditions, including indoor and outdoor temperatures, a state of charge of the integrated thermal energy storage module, a temperature of the energy storage medium of the integrated thermal energy storage module, and the costs to operate the thermal management system. Based on the operating conditions, the thermal management system operates using a primary heating model 20 or a primary cooling model 30.

[0016] Typically, the thermal management system operates under the primary heating model 20 during cool seasons and, accordingly, the integrated thermal energy storage module is leveraged for efficient heating operations. Under the primary heating model 20, depending on the current operating conditions, the thermal management system intelligently operates in either a charging-heating mode 40, a discharging-heating mode 42, a normal heating mode 44, a standby mode 46, or a normal cooling mode 48.

[0017] Conversely, the thermal management system typically operates under the primary cooling model 30 during warm seasons and, accordingly, the integrated thermal energy storage module is leveraged for efficient cooling operations. Under the primary cooling model 30, depending on the current operating conditions, the thermal management system intelligently operates in either the charging-cooling mode 50, the discharging-cooling mode 52, the normal cooling mode 48, the standby mode 46, or the normal heating mode 44.

Exemplary Heat Pump System Having Integrated Thermal Energy Storage

[0018] In an effort to provide a better understanding of the features of the disclosure, an exemplary thermal management system in the form of a heat pump system is described in detail, which incorporates thermal energy storage.

[0019] FIG. 2 shows exemplary components of a heat pump system 100 for a building having integrated thermal energy storage. In the illustrated example, the heat pump system 100 includes an outside air heat exchanger 104, an inside air heat exchanger 108, a refrigerant loop 112, a compressor 116, and an expander 120. Additionally, the heat pump system 100 includes or is integrated with a thermal energy storage module 130 by way of a plurality of switchable valves 140.

[0020] The outside air heat exchanger 104 is configured to transfer heat between a first environment, i.e., including outside air 106, and a refrigerant circulating through the refrigerant loop 112. Structurally, in at least some embodiments, the outside air heat exchanger 104 includes a series of coiled metal tubes or metal fins (not shown), through which the refrigerant circulates, that increase the surface area for heat exchange and facilitate the efficient absorption or dissipation of thermal energy. The outside air heat exchanger 104 is arranged outside of the building and, in at least some embodiments, is provided in a housing, e.g., metal casing, (not shown) to protect it from environmental factors. Additionally, in some embodiments, a fan is mounted inside the housing to blow air over the coiled tubes or fins of the outside air heat exchanger 104 to provide greater heat transfer.

[0021] The inside air heat exchanger 108 is configured to transfer heat between the refrigerant circulating through the refrigerant loop 112 and a second environment, i.e., including inside air 110. Structurally, in at least some embodiments, the inside air heat exchanger 108 includes a series of coiled metal tubes or metal fins (not shown), through which the refrigerant circulates, that increase the surface area for heat exchange and facilitate the efficient absorption or dissipation of thermal energy. The inside air heat exchanger 108 is arranged inside of the building and, in at least some embodiments, is arranged within an indoor ventilation system, such that a fan mounted within the ventilation system blows air through the coiled tubes or fins of the outside air heat exchanger 104 to distribute conditioned air throughout the building.

[0022] The refrigerant loop 112 is a closed, continuous loop system that circulates refrigerant through the various components of the heat pump system 100, enabling the transfer of thermal energy. In some embodiments, the refrigerant loop 112 may more broadly take the form of a thermal energy transport fluid loop that circulates thermal energy transport fluid, including refrigerants, water, glycol solutions (antifreeze), or the like. Thus, references herein to the refrigerant and the refrigerant loop 112 should be understood to alternatively incorporate any thermal energy transport fluid. The refrigerant loop 112 consists of tubing that connects the components of the heat pump system 100, including the outside air heat exchanger 104, the inside air heat exchanger 108, the compressor 116, and the expander 120. The refrigerant flows through these components in a cyclic process, in some cases undergoing phase changes between liquid and gas as it absorbs or releases heat. Additionally, as will be discussed in greater detail below, the refrigerant loop 112 also connects with the thermal energy storage module 130 by way of the plurality of switchable valves 140 to store thermal energy in and release thermal energy from the thermal energy storage module 130.

[0023] The compressor 116 is positioned in the refrigerant loop 112 along a first circulation path between the inside air heat exchanger 108 and the outside air heat exchanger 104. The compressor 116 is configured to compress and circulate the refrigerant through the refrigerant loop 112. The compressor 116 includes a motor that uses electrical energy to compress the refrigerant to increase both the pressure and the temperature of the refrigerant, generally after the refrigerant has absorbed heat from elsewhere along the refrigerant loop 112. In some embodiments, the heat pump system 100 includes multiple compressors 116.

[0024] The expander 120 is positioned in the refrigerant loop 112 along a second circulation path between the inside air heat exchanger 108 and the outside air heat exchanger 104, which is different from the first circulation path including the compressor 116. The expander 120 is configured to further regulate the pressure of the refrigerant as it moves through the refrigerant loop 112. Particularly, the expander 120 includes an expansion valve or capillary tube configured to lower both the pressure and the temperature of the refrigerant, generally after the refrigerant has released heat elsewhere along the refrigerant loop 112. In some embodiments, the heat pump system 100 includes multiple expanders 120.

[0025] It should be appreciated that the illustrated embodiment of the heat pump system 100 is in the form of an air-source heat pump. However, in alternative embodiments, the heat pump system 100 may take the form of a ground-source (geothermal) heat pump or a water-source heat pump. Ground-source (geothermal) heat pumps transfer heat between the building and the ground or groundwater. These systems use underground refrigerant loops that absorb heat from the earth or release heat to the earth, which remains at a relatively constant temperature year-round. Similarly, water-source heat pumps exchange heat with a water tank in the building or with a body of water, such as a lake, river, or well, or. These systems draw heat from the water for heating or discharge heat into the water for cooling.

[0026] In any case, the heat pump system 100 advantageously includes the thermal energy storage module 130. The thermal energy storage module 130 is configured to store excess thermal energy for later release. Particularly, the thermal energy storage module 130 captures excess thermal energy when the heat pump system 100 is producing more thermal energy than is needed for immediate use. For example, during periods of high heat pump efficiency or low demand, the heat pump system 100 can divert excess thermal energy into the thermal energy storage module 130. When demand increases or the heat pump system 100 is not operating optimally, the stored thermal energy can be released back into the refrigerant loop 112 to meet heating or cooling needs. This process helps balance the load, reduce peak energy consumption, and improve overall system efficiency.

[0027] The thermal energy storage module 130 typically consists of one or more insulated storage tanks (not shown) filled with a thermal storage medium, such as water or phase-change materials. In the illustrated embodiment, the thermal energy storage module 130 includes phase-change materials 134 and a TES heat exchanger 138. The TES heat exchanger 138 is connected in the refrigerant loop 112 via the plurality of switchable valves 140 that are operated to direct the flow of refrigerant between the thermal energy storage module 130 and the rest of the heat pump system 100. In some embodiments, the thermal energy storage module 130 has its own compressor or expander (not shown) such that it is easier to retrofit existing designs compared to fully relying on the compressor 116 and expander 120 of the heat pump system 100. The compressor within the thermal energy storage module 130 could be optimized particularly for the thermal energy storage module 130, and thus could be more efficient and lower cost.

[0028] The phase-change materials 134 in the thermal energy storage module 130 are substances that store and release thermal energy through phase changes, typically from solid to liquid or vice versa. It should be appreciated that phase-change materials 134 may alternatively include any other thermal storage medium, such as water. When the heat pump system 100 generates excess thermal energy, the phase-change materials 134 can absorb thermal energy and undergo a phase change, effectively storing the thermal energy at a constant temperature. Conversely, when there is a demand for thermal energy, the phase-change materials 134 can release the stored thermal energy as they revert to their original phase.

[0029] In one embodiment, the thermal energy storage module 130 includes two different thermal storage mediums (not shown), in particular two different phase-change materials 134. A first of the phase-change materials 134 is optimized for releasing thermal energy into the indoors environment while heating the indoors environment. A second of the phase-change materials 134 is optimized for storing thermal energy extracted from the indoors environment while cooling the indoors environment. The two different phase-change materials 134 may, for example, be different materials or different mixtures of materials.

[0030] The TES heat exchanger 138 in the thermal energy storage module 130 is configured to transfer heat between the refrigerant circulating through the refrigerant loop 112 and the phase-change materials 134. Structurally, in at least some embodiments, the TES heat exchanger 138 includes a series of coiled metal tubes or metal fins (not shown), through which the refrigerant circulates. The TES heat exchanger 138 is arranged within or adjacent to the phase-change materials 134 to maximize the contact surface area and ensure efficient heat exchange.

[0031] The TES heat exchanger 138 is connected between an inlet connection and an outlet connection (not shown) of the thermal energy storage module 130, such that refrigerant from the refrigerant loop 112 can flow through the TES heat exchanger 138 to store or release thermal energy in the phase-change materials 134. It should be appreciated that the inlet connection and outlet connection of the thermal energy storage module 130 do not necessarily refer to specific refrigerant connections, since the refrigerant may flow in either direction through the thermal energy storage module 130. Thus, the inlet connection and outlet connection of the thermal energy storage module 130 should be understood as interchangeable.

[0032] In some embodiments, the thermal energy storage module 130 further comprises a resistive heating element 136 arranged adjacent to or within the phase-change materials 134. The resistive heating element 136 typically consists of a high-resistance metal wire, which is coiled or formed into a specific shape to maximize surface area and which is arranged within an insulating material, such as ceramic. When electricity is passed through the resistive heating element 136, it heats up and thermal energy is absorbed by the phase-change materials 134, thereby charging the thermal energy storage module 130.

[0033] The plurality of switchable valves 140 are suitably arranged and operated to manage the storage and release of thermal energy within the thermal energy storage module 130, as well as direct the flow of refrigerant through the outside air heat exchanger 104 and/or the inside air heat exchanger 108. In some embodiments, the plurality of switchable valves 140 may include multi-way valves (e.g., 3-way valves), or equivalent arrangements of multiple valves. The plurality of switchable valves 140 may include a wide variety of possible configurations that enable the thermal energy storage module 130 to be selectively bypassed in a first switching state, selectively connected in series with the outside air heat exchanger 104 in a second switching state, and selectively connected in series with the inside air heat exchanger 108 in a third switching state.

[0034] Additionally, in some embodiments, the plurality of switchable valves 140 have a configuration that enables the compressor 116 and/or the expander 120 to, in different switching states, be selectively connected in the refrigerant loop 112 between the outside air heat exchanger 104 and TES heat exchanger 138, selectively connected in the refrigerant loop 112 between the TES heat exchanger 138 and the inside air heat exchanger 108, and selectively connected in the refrigerant loop 112 between the outside air heat exchanger 104 and the inside air heat exchanger 108. Finally, in some embodiments, the plurality of switchable valves 140 have a configuration that enables the compressor 116 and/or the expander 120 to, in different switching states, be reversed in the refrigerant loop 112.

[0035] In at least some embodiments, the heat pump system 100 further includes a controller 150 configured to manage the overall operation of the heat pump system 100. To these ends, the controller 150 is configured to monitor a variety of parameters including, for example, a temperature of the indoors environment, an ambient temperature of the outdoors environment, a temperature of the phase-change materials 134, and a state of charge of the thermal energy storage module 130. By continuously monitoring these parameters, the controller 150 makes real-time adjustments to the operation of the heat pump system 100, such as modulating the speed of the compressor 116 or adjusting the plurality of switchable valves 140 to store thermal energy in the thermal energy storage module 130 or release thermal energy from the thermal energy storage module 130.

[0036] In some embodiments, the controller 150 is operably connected to a variety of temperature sensors configured to measure different temperatures within the heat pump system 100. These temperature sensors may comprise thermocouples or thermistors, positioned strategically to measure respective temperatures. In one embodiment, an indoor temperature sensor 152 measures one or both of an ambient indoor temperature (e.g., at a thermostat) and a temperature of the air entering the inside air heat exchanger 108. In one embodiment, an outdoor temperature sensor 154 measures one or both of an ambient outdoor temperature and a temperature of the air entering the outside air heat exchanger 104. In one embodiment, an PCM temperature sensor 156 measures a temperature of the phase-change materials 134.

[0037] The controller 150 is configured to selectively operate the heat pump system 100 in either a heating mode, a cooling mode, or a standby mode. In the standby mode, the heat pump system 100 is not actively heating or cooling but remains ready to engage when needed.

[0038] In the heating mode, the heat pump system 100 operates by transferring heat from the outside air to the inside of a building using the refrigerant loop 112. The controller 150 operates the compressor 116 to compress the refrigerant, increasing its temperature and pressure. The higher-temperature, higher-pressure refrigerant from the compressor 116 is circulated through the inside air heat exchanger 108, where it releases heat to warm the inside air 110. Next, the refrigerant passes through the expander 120, where it undergoes a reduction in pressure and temperature. The lower-temperature, lower-pressure refrigerant from the expander 120 is circulated through the outside air heat exchanger 104, where it absorbs heat from the outside air, even in cold conditions. The refrigerant then returns to the compressor 116 to repeat the cycle.

[0039] In the cooling mode, the heat pump system 100 works in reverse to transfer heat from inside the building to the outside environment. The controller 150 operates the compressor 116 to compress the refrigerant, increasing its temperature and pressure. The higher-temperature, higher-pressure refrigerant from the compressor 116 is circulated through the outside air heat exchanger 104, where it releases heat into the outside air 106. Next, the refrigerant passes through the expander 120, where it undergoes a reduction in pressure and temperature. The lower-temperature, lower-pressure refrigerant from the expander 120 is circulated through the inside air heat exchanger 108, where it absorbs heat from the inside air 110. The refrigerant then returns to the compressor 116 to repeat the cycle.

[0040] In addition to operating the heat pump system 100 in the conventional heating or cooling modes, the controller 150 operates the plurality of switchable valves 140 to control the heat pump system 100 to store thermal energy in the thermal energy storage module 130 or to release thermal energy from the thermal energy storage module 130 in either of the heating and cooling modes, as needed.

[0041] When the heat pump system 100 operates to store thermal energy in the thermal energy storage module 130 (i.e., in a charging mode), the controller 150 operates the plurality of switchable valves 140 in a specific manner to direct refrigerant flow from the compressor 116 or from the expander 120 towards the thermal energy storage module 130. In the charging mode, the controller 150 operates the compressor 116 to circulate the refrigerant such that excess thermal energy generated during operation, is transferred to the thermal energy storage module 130 instead of being released into the inside air 110 or released into the outside air 106. Particularly, in the cooling mode, the thermal energy storage module 130 stores thermal energy absorbed from inside air 110 for the purpose of cooling the environment. Conversely, in the heating mode, the thermal energy storage module 130 stores thermal energy absorbed from outside air 106.

[0042] When the heat pump system 100 operates to release thermal energy from the thermal energy storage module 130 (i.e., in a discharging mode), the controller 150 operates the plurality of switchable valves 140 in a specific manner to direct refrigerant flow from the thermal energy storage module 130 to the inside air heat exchanger 108 or to the outside air heat exchanger 104. In the discharging mode, the controller 150 operates the compressor 116 to circulate the refrigerant such that thermal energy is released from the thermal energy storage module 130 instead of being absorbed from the outside air 106 or absorbed from the inside air 110. Particularly, in the heating mode, the thermal energy storage module 130 releases thermal energy into the inside air 110 for the purpose of heating the building. Conversely, in the cooling mode, the thermal energy storage module 130 releases thermal energy into the outside air 106.

[0043] In some embodiments, the controller 150 incorporates intelligent algorithms that determine the optimal times for charging and discharging the thermal energy storage module 130 based on predictive analytics of energy demand, weather forecasts, and electricity tariff rates. The controller 150 adjusts the operation of the compressor 116 and adjusts the flow paths of the refrigerant loop 112 using the plurality of switchable valves 140 to store or release thermal energy in the thermal energy storage module 130, to minimize energy costs, maximize efficiency, and prolong the lifetime of the heat pump system 100.

[0044] In at least some embodiments, the heat pump system 100 further includes an IoT gateway 170. The IoT gateway 170 acts as a communication bridge between the controller 150 and a cloud backend 180 and/or a mobile electronic device 190. The IoT gateway 170 includes, for example, a microprocessor and a network communications module including one or more transceivers (e.g., Wi-Fi, Ethernet, or cellular) for connectivity to the cloud backend 180 and/or the mobile electronic device 190. The IoT gateway 170 enables data exchange and remote monitoring by transmitting system performance metrics, such as sensor data, energy usage, and operational status, to the cloud backend 180 and/or the mobile electronic device 190. Additionally, the IoT gateway 170 enables user control of the heat pump system 100 via a mobile application on the mobile electronic device 190 or via a web application of the cloud backend 180.

[0045] In at least some embodiments, the cloud backend 180 includes one or more servers that act as the central hub for data processing, storage, and system management. The cloud backend 180 receives data from the IoT gateway 170, including sensor data, energy usage, and operational status, and processes and stores this information for analysis and optimization. In some embodiments, the cloud backend 180 also facilitates user interaction by communicating with the mobile electronic device 190 or with another computing device, allowing users to remotely monitor and control the heat pump system 100 via the mobile application or the web application.

[0046] In at least some embodiments, the mobile electronic device 190 operates as a user interface for remotely monitoring and controlling the heat pump system 100. The mobile electronic device 190 communicates with the IoT gateway 170, either directly or via the cloud backend 180, allowing users to monitor system performance, adjust temperature settings, schedule heating or cooling modes, and the like.

Methods for Controlling a Thermal Management System Having Thermal Energy Storage

[0047] FIG. 3 shows a flow diagram for a method 200 for operating a thermal management system, such as the heat pump system 100, which incorporates a thermal energy storage module 130. The method 200 advantageously optimizes the storage and release of thermal energy from the integrated thermal energy storage module during heating and cooling operations to provide energy-saving demand response.

[0048] The method 200 begins with measuring operating parameters of a thermal management system having a thermal energy storage module (block 210). Particularly, the controller 150 of the heat pump system 100 operates one or more of the sensors of the heat pump system 100 to measure values of a plurality of parameters (or operating conditions) of the heat pump system 100. Particularly, the controller 150 operates the indoor temperature sensor 152 to measure the temperature T.sub.indoor of the indoor environment, which is temperature-regulated by the heat pump system 100, and in which the inside air heat exchanger 108 is arranged. The controller 150 operates the outdoor temperature sensor 154 to measure an ambient temperature T.sub.amb of the outdoor environment in which the outside air heat exchanger 104 is arranged. The controller 150 operates the PCM temperature sensor 156 to measure a temperature T.sub.PCM of the phase-change materials 134.

[0049] Additionally, the controller 150 is configured to estimate or directly measure a state of charge of the thermal energy storage module 130, e.g., based on sensor data of a variety of sensors (not shown). Alternatively, the controller 150 receives an estimate of the state of charge of the thermal energy storage module 130 from another device that estimates the state of charge.

[0050] Finally, the controller 150 is configured to receive a time-of-use rate plan, indicating at least one window of time during which a cost of electricity to operate the heat pump system 100 is relatively increased, referred to herein as a peak time window, compared to another window of time during which the cost of electricity to operate the heat pump system 100 is relatively reduced, referred to herein as an off-peak time window. The time-of-use rate plan may, for example, be input by a user via a mobile application or a web application using the mobile electronic device 190 and received by the controller 150 from the mobile electronic device 190 via the IoT gateway 170. Alternatively, the controller 150 may receive the time-of-use rate plan directly from a utility company that provides the electricity, i.e., from a remote server.

[0051] The method 200 continues with selecting, based on the measured parameters, an operating mode of the thermal management system (block 220). Particularly, the controller 150 of the heat pump system 100 selects an operating mode of the heat pump system 100 based on the plurality of parameters of the heat pump system 100, and with reference to one or more setpoint temperatures or threshold values, as will be discussed below. The heat pump system 100 can be operated in a variety of different operating modes, and the controller 150 intelligently selects the appropriate operating mode.

[0052] In a conventional or normal heating mode, the heat pump system 100 operates to draw thermal energy from the outdoors environment and release the thermal energy into the indoors environment, thereby heating the indoors environment. In a conventional or normal cooling mode, the heat pump system 100 operates to draw thermal energy from the indoors environment and release the thermal energy into the outdoors environment, thereby cooling the indoors environment. In a standby mode, the heat pump system 100 is not actively heating or cooling but remains ready to engage when needed.

[0053] In a charging-heating mode, the heat pump system 100 operates to draw thermal energy from the outdoors environment and store the thermal energy in the thermal energy storage module 130, thereby charging the thermal energy storage module 130. In a discharging-heating mode, the heat pump system 100 operates to draw thermal energy from the thermal energy storage module 130 and release the thermal energy into the indoors environment, thereby heating the indoors environment and discharging the thermal energy storage module 130.

[0054] In a charging-cooling mode, the heat pump system 100 operates to draw thermal energy from the indoors environment and store the thermal energy in the thermal energy storage module 130, thereby cooling the indoors environment and charging the thermal energy storage module 130. In a discharging-cooling mode, the heat pump system 100 operates to draw thermal energy from the thermal energy storage module 130 and release the thermal energy into the outdoors environment, thereby discharging the thermal energy storage module 130.

[0055] FIG. 4 shows a flow diagram for a method 300 for selecting a control model for operating a thermal management system. Particularly, in at least some embodiments, the controller 150 uses two different control models for operating the heat pump system 100: a primary heating model 320 and a primary cooling model 330. In the primary heating model 320, the heat pump system 100 is primarily, but not exclusively, used to heat the indoors environment and the thermal energy storage module 130 is leveraged only for heating purposes. Typically, the primary heating model 32 will be used by the controller 150 during cool seasons. Conversely, in the primary cooling model 330, the heat pump system 100 is primarily, but not exclusively, used to cool the indoors environment and the thermal energy storage module 130 is leveraged only for cooling purposes. Typically, the primary cooling model 330 will be used by the controller 150 during warm seasons.

[0056] The controller 150 determines an average of the ambient temperature T.sub.amb of the outdoors environment over a predetermined time period (e.g., over the previous month). Next, the controller 150 compares (block 310) the average of the ambient temperature T.sub.amb with a threshold temperature. In some embodiments, the first threshold temperature is a setpoint temperature T.sub.spc for cooling the indoors environment. In some embodiments, the first threshold temperature is the setpoint temperature T.sub.spc for cooling the indoors environment offset by a predetermined number of degrees (e.g., T.sub.spc2). In response to the average of the ambient temperature T.sub.amb being less than the first threshold temperature (e.g., Monthly.sub.Average(T.sub.amb)<T.sub.spc2), the controller 150 selects the primary heating model 320 for operating the heat pump system 100. In response to the average of the ambient temperature T.sub.amb being greater than or equal to the first threshold temperature (e.g., Monthly.sub.Average(T.sub.amb)T.sub.spc2), the controller 150 selects the primary cooling model 330 for operating the heat pump system 100.

[0057] FIG. 5A shows a flow diagram for a method 400A for controlling the thermal management system using the primary heating model 320. Particularly, once it has been decided to operate using the primary heating model 320 (i.e., when Monthly.sub.Average(T.sub.amb)<T.sub.spc2), the controller 150 compares (block 404 and block 406) the temperature T.sub.indoor of the indoors environment with a deadband temperature range around a setpoint temperature for the indoors environment. In the primary heating model 320, the deadband temperature range is defined by a positive and negative deadband offset T.sub.db around the setpoint temperature T.sub.sph for heating the indoors environment (i.e., T.sub.sphT.sub.db).

[0058] In response to the temperature T.sub.indoor of the indoors environment being outside of the deadband temperature range, the controller 150 selects an operating mode that causes the indoor environment to be heated or cooled as needed. In contrast, in response to the temperature T.sub.indoor of the indoors environment being within the deadband temperature range, the controller 150 selects an operating mode that manages the state of charge of the thermal energy storage module 130 for the purpose of future heating operations.

[0059] More particularly, the controller 150 checks (block 404) whether the temperature T.sub.indoor of the indoors environment is less than the deadband temperature range (i.e., T.sub.indoorT.sub.sphT.sub.db). In response to the temperature T.sub.indoor of the indoors environment being less than the deadband temperature range, the controller 150 selects an operating mode that causes the indoor environment to be heated as needed, e.g., selects the discharging-heating mode 408 or the normal heating mode 410.

[0060] In some embodiments, when the temperature T.sub.indoor of the indoors environment is less than the deadband temperature range (i.e., T.sub.indoorT.sub.sphT.sub.db), the controller 150 evaluates one or more additional conditions to determine whether the discharging-heating mode 408 or the normal heating mode 410 should be selected.

[0061] In one embodiment, the controller 150 checks (block 418) whether a current time is within a peak time window, as defined by a time-of-use rate plan (i.e., TOU=1), during which the cost of electricity to operate the heat pump system 100 is relatively increased, compared to an off-peak time window during which the cost of electricity to operate the heat pump system 100 is relatively reduced. In response to the current time being within a peak time window (i.e., TOU=1), the controller 150 selects the discharging-heating mode 408. Otherwise, in response to the current time being outside of a peak time window (i.e., TOU=0), the controller 150 selects the normal heating mode 410.

[0062] In one embodiment, the controller 150 also checks (block 420) whether the state of charge of the thermal energy storage module 130 exceeds a predetermined threshold. The predetermined threshold may be a value (e.g., 0 or 0% SOC) indicating a minimum desired state of charge of the thermal energy storage module 130. In response to the state of charge exceeding the predetermined threshold (e.g., SOC>0), the controller 150 selects the discharging-heating mode 408. Otherwise, in response to the state of charge being less than or equal to the predetermined threshold (e.g., SOC=0), the controller 150 selects the normal heating mode 410.

[0063] In one embodiment, the controller 150 also compares (block 422) the temperature T.sub.PCM of the phase-change materials 134 with the ambient temperature T.sub.amb of the outdoors environment. In response to the temperature T.sub.PCM of the phase-change materials 134 being greater than the ambient temperature T.sub.amb of the outdoors environment (i.e., T.sub.PCM>T.sub.amb), the controller 150 selects the discharging-heating mode 408. Otherwise, in response to the temperature T.sub.PCM of the phase-change materials 134 being less than ambient temperature T.sub.amb of the outdoors environment (i.e., T.sub.PCMT.sub.amb), the controller 150 selects the normal heating mode 410.

[0064] In the illustrated embodiment, the controller 150 selects the discharging-heating mode 408 only in response to all three conditions (i.e., TOU=1, SOC>0, and T.sub.PCM>T.sub.amb) being true. Otherwise, the controller 150 selects the normal heating mode 410. However, it should be appreciated that different combinations or a subset of these conditions might be adopted in some embodiments.

[0065] With reference again to block 404, if it was determined that the temperature T.sub.indoor of the indoors environment is not less than the deadband temperature range (i.e., T.sub.sphT.sub.dbT.sub.indoor), then the controller 150 checks (block 406) whether the temperature T.sub.indoor of the indoors environment is within the deadband temperature range (i.e., T.sub.sphT.sub.dbT.sub.indoorT.sub.sph+T.sub.db). In response to the temperature T.sub.indoor of the indoors environment being within the deadband temperature range, the controller 150 selects an operating mode to manage the state of charge of the thermal energy storage module 130, as needed, for the purpose of future heating operations, e.g., selects the charging-heating mode 416 or the standby mode 414.

[0066] In some embodiments, when the temperature T.sub.indoor of the indoors environment is within the deadband temperature range (i.e., T.sub.sphT.sub.dbT.sub.indoorT.sub.sph+T.sub.db), the controller 150 evaluates one or more additional conditions to determine whether the charging-heating mode 416 or the standby mode 414 should be selected.

[0067] More particularly, in one embodiment, the controller 150 checks (block 424) whether a current time is outside of a peak time window, as defined by a time-of-use rate plan (i.e., TOU=0), during which the cost of electricity to operate the heat pump system 100 is relatively increased, compared to an off-peak time window during which the cost of electricity to operate the heat pump system 100 is relatively reduced. In response to the current time being outside of a peak time window (i.e., TOU=0), the controller 150 selects the charging-heating mode 416. Otherwise, in response to the current time being within a peak time window (i.e., TOU=1), the controller 150 selects the standby mode 414.

[0068] In one embodiment, the controller 150 also checks (block 426) whether the state of charge of the thermal energy storage module 130 is less than a predetermined threshold. The predetermined threshold may be a value (e.g., 1 or 100% SOC) indicating a maximum desired state of charge of the thermal energy storage module 130. In response to the state of charge being less than the predetermined threshold (e.g., SOC<1), the controller 150 selects the charging-heating mode 416. Otherwise, in response to the state of charge being greater than or equal to the predetermined threshold (e.g., SOC=1), the controller 150 selects the standby mode 414.

[0069] In the illustrated embodiment, the controller 150 selects the charging-heating mode 416 in response to both conditions (i.e., TOU=0 and SOC<1) being true. Otherwise, the controller 150 selects the standby mode 414. However, it should be appreciated that different combinations or only one of the conditions might be adopted in some embodiments.

[0070] With reference again to block 406, if it was determined that the temperature T.sub.indoor of the indoors environment is not within the deadband temperature range, then in response to the temperature T.sub.indoor of the indoors environment being greater than the deadband temperature range (i.e., T.sub.indoor>T.sub.sph+T.sub.db), the controller 150 selects an operating mode that causes the indoor environment to be cooled as needed, e.g., selects the normal cooling mode 412 or the standby mode 414.

[0071] In some embodiments, when the temperature T.sub.indoor of the indoors environment is greater than the deadband temperature range (i.e., T.sub.indoor>T.sub.sph+T.sub.db), the controller 150 evaluates one or more additional conditions to determine whether the normal cooling mode 412 or the standby mode 414 should be selected.

[0072] More particularly, in one embodiment, the controller 150 also compares (block 428) the ambient temperature T.sub.amb of the outdoors environment with a second threshold temperature. In at least one embodiment, the predetermined threshold temperature is a building balance temperature T.sub.bal that indicates the outdoors temperature at which the heat gains of a building (such as from internal sources like occupants, appliances, and lighting) are equal to the heat losses (such as through walls, windows, and roofs). In other words, the building balance temperature T.sub.bal is the temperature at which the building requires neither heating nor cooling to maintain the indoor temperature. In response to the ambient temperature T.sub.amb of the outdoors environment being greater than the building balance temperature T.sub.bal (i.e., T.sub.amb>T.sub.bal), the controller 150 selects the normal cooling mode 412. Otherwise, in response to the ambient temperature T.sub.amb of the outdoors environment being less than the building balance temperature T.sub.bal (i.e., T.sub.ambT.sub.bal), the controller 150 selects the standby mode 414. In this case, it can be expected that the indoors environment will cool naturally due to the cool outdoors temperature.

[0073] FIG. 5B shows a flow diagram for a method 400B for controlling the thermal management system using the primary cooling model 330. Particularly, once it has been decided to operate using the primary cooling model 330 (i.e., when Monthly.sub.Average(T.sub.amb)T.sub.spc2), the controller 150 compares (block 430 and block 432) the temperature T.sub.indoor of the indoors environment with a deadband temperature range around a setpoint temperature for the indoors environment. In the primary cooling model 330, the deadband temperature range is defined by a positive and negative deadband offset T.sub.db around the setpoint temperature T.sub.spc for cooling the indoors environment (i.e., T.sub.spcT.sub.db).

[0074] In response to the temperature T.sub.indoor of the indoors environment being outside of the deadband temperature range, the controller 150 selects an operating mode that causes the indoor environment to be heated or cooled as needed. In contrast, in response to the temperature T.sub.indoor of the indoors environment being within the deadband temperature range, the controller 150 selects an operating mode that manages the state of charge of the thermal energy storage module 130 for the purpose of future cooling operations.

[0075] More particularly, the controller 150 checks (block 430) whether the temperature T.sub.indoor of the indoors environment is greater than the deadband temperature range (i.e., T.sub.indoorT.sub.spc+T.sub.db). In response to the temperature T.sub.indoor of the indoors environment being greater than the deadband temperature range, the controller 150 selects an operating mode that causes the indoor environment to be cooled as needed, e.g., selects the charging-cooling mode 434 or the normal cooling mode 412.

[0076] In some embodiments, when the temperature T.sub.indoor of the indoors environment is greater than the deadband temperature range (i.e., T.sub.indoorT.sub.spc+T.sub.db), the controller 150 evaluates one or more additional conditions to determine whether the charging-cooling mode 434 or the normal cooling mode 412 should be selected.

[0077] In one embodiment, the controller 150 checks (block 438) whether a current time is within a peak time window, as defined by a time-of-use rate plan (i.e., TOU=1), during which the cost of electricity to operate the heat pump system 100 is relatively increased, compared to an off-peak time window during which the cost of electricity to operate the heat pump system 100 is relatively reduced. In response to the current time being within a peak time window (i.e., TOU=1), the controller 150 selects the charging-cooling mode 434. Otherwise, in response to the current time being outside of a peak time window (i.e., TOU=0), the controller 150 selects the normal cooling mode 412.

[0078] In one embodiment, the controller 150 also checks (block 440) whether the state of charge of the thermal energy storage module 130 is less than a predetermined threshold. The predetermined threshold may be a value (e.g., 1 or 100% SOC) indicating a maximum desired state of charge of the thermal energy storage module 130. In response to the state of charge being less than the predetermined threshold (e.g., SOC<1), the controller 150 selects the charging-cooling mode 434. Otherwise, in response to the state of charge being greater than or equal to the predetermined threshold (e.g., SOC=1), the controller 150 selects the normal cooling mode 412.

[0079] In one embodiment, the controller 150 also compares (block 442) the temperature T.sub.PCM of the phase-change materials 134 with the ambient temperature T.sub.amb of the outdoors environment. In response to the temperature T.sub.PCM of the phase-change materials 134 being less than the ambient temperature T.sub.amb of the outdoors environment (i.e., T.sub.PCM<T.sub.amb), the controller 150 selects the charging-cooling mode 434. Otherwise, in response to the temperature T.sub.PCM of the phase-change materials 134 being greater than ambient temperature T.sub.amb of the outdoors environment (i.e., T.sub.PCMT.sub.amb), the controller 150 selects the normal cooling mode 412.

[0080] In the illustrated embodiment, the controller 150 selects the charging-cooling mode 434 only in response to all three conditions (i.e., TOU=1, SOC<1, and T.sub.PCM<T.sub.amb) being true. Otherwise, the controller 150 selects the normal cooling mode 412. However, it should be appreciated that different combinations or a subset of these conditions might be adopted in some embodiments.

[0081] With reference again to block 430, if it was determined that the temperature T.sub.indoor of the indoors environment is not greater than the deadband temperature range (i.e., T.sub.spc+T.sub.dbT.sub.indoor), then the controller 150 checks (block 432) whether the temperature T.sub.indoor of the indoors environment is within the deadband temperature range (i.e., T.sub.spcT.sub.dbT.sub.indoorT.sub.spc+T.sub.db). In response to the temperature T.sub.indoor of the indoors environment being within the deadband temperature range, the controller 150 selects an operating mode to manage the state of charge of the thermal energy storage module 130, as needed, for the purpose of future cooling operations, e.g., selects the discharging-cooling mode 436 or the standby mode 414.

[0082] In some embodiments, when the temperature T.sub.indoor of the indoors environment is within the deadband temperature range (i.e., T.sub.spcT.sub.dbT.sub.indoorT.sub.spc+T.sub.db), the controller 150 evaluates one or more additional conditions to determine whether the discharging-cooling mode 436 or the standby mode 414 should be selected.

[0083] More particularly, in one embodiment, the controller 150 checks (block 446) whether a current time is outside of a peak time window, as defined by a time-of-use rate plan (i.e., TOU=0), during which the cost of electricity to operate the heat pump system 100 is relatively increased, compared to an off-peak time window during which the cost of electricity to operate the heat pump system 100 is relatively reduced. In response to the current time being outside of a peak time window (i.e., TOU=0), the controller 150 selects the discharging-cooling mode 436. Otherwise, in response to the current time being within a peak time window (i.e., TOU=1), the controller 150 selects the standby mode 414.

[0084] In one embodiment, the controller 150 also checks (block 448) whether the state of charge of the thermal energy storage module 130 is greater than a predetermined threshold. The predetermined threshold may be a value (e.g., 0 or 0% SOC) indicating a minimum desired state of charge of the thermal energy storage module 130. In response to the state of charge being less than the predetermined threshold (e.g., SOC>0), the controller 150 selects the discharging-cooling mode 436. Otherwise, in response to the state of charge being less than or equal to the predetermined threshold (e.g., SOC=0), the controller 150 selects the standby mode 414.

[0085] In the illustrated embodiment, the controller 150 selects the discharging-cooling mode 436 in response to both conditions (i.e., TOU=0 and SOC>0) being true. Otherwise, the controller 150 selects the standby mode 414. However, it should be appreciated that different combinations or only one of the conditions might be adopted in some embodiments.

[0086] With reference again to block 432, if it was determined that the temperature T.sub.indoor of the indoors environment is not within the deadband temperature range, then in response to the temperature T.sub.indoor of the indoors environment being less than the deadband temperature range (i.e., T.sub.indoor<T.sub.spcT.sub.db), the controller 150 selects an operating mode that causes the indoor environment to be heated as needed, e.g., selects the normal heating mode 410 or the standby mode 414.

[0087] In some embodiments, when the temperature T.sub.indoor of the indoors environment is less than the deadband temperature range (i.e., T.sub.indoor<T.sub.spcT.sub.db), the controller 150 evaluates one or more additional conditions to determine whether the normal heating mode 410 or the standby mode 414 should be selected.

[0088] More particularly, in one embodiment, the controller 150 also compares (block 450) the ambient temperature T.sub.amb of the outdoors environment with a second threshold temperature. In at least one embodiment, the predetermined threshold temperature is a building balance temperature T.sub.bal that indicates the outdoors temperature at which the heat gains of a building (such as from internal sources like occupants, appliances, and lighting) are equal to the heat losses (such as through walls, windows, and roofs). In other words, the building balance temperature T.sub.bal is the temperature at which the building requires neither heating nor cooling to maintain the indoor temperature. In response to the ambient temperature T.sub.amb of the outdoors environment being less than the building balance temperature T.sub.bal (i.e., T.sub.amb<T.sub.bal), the controller 150 selects the normal heating mode 410. Otherwise, in response to the ambient temperature T.sub.amb of the outdoors environment being greater than the building balance temperature T.sub.bal (i.e., T.sub.ambT.sub.bal), the controller 150 selects the standby mode 414. In this case, it can be expected that the indoors environment will warm naturally due to the warm outdoors temperature.

[0089] In some embodiments, in which the thermal energy storage module 130 incorporates the resistive heating element 136, the controller 150 is configured to selectively operate the resistive heating element 136 to add thermal energy to the thermal energy storage module 130 by heating the phase-change materials 134. In some embodiments, the controller 150 operates the resistive heating element 136 as an alternative to the charging-heating mode 416 and does so in response to the same conditions discussed above with respect to the charging-heating mode 416.

[0090] Moreover, in one embodiment, the controller 150 determines and compares (i) an energy-efficiency of operating the resistive heating element 136 to store thermal energy in the thermal energy storage module 130 and (ii) an energy-efficiency of operating a compressor 116 to circulate refrigerant through the TES heat exchanger 138 to store thermal energy in the thermal energy storage module 130 (i.e., in the charging-heating mode 416). The controller 150 determines these energy-efficiencies, for example, based on the ambient temperature T.sub.amb of the outdoors environment and the temperature T.sub.PCM of the phase-change materials 134. In response to determining that it is more energy-efficient to operate the resistive heating element 136 to store thermal energy in the thermal energy storage module 130, the controller 150 operates the resistive heating element 136 to store additional thermal energy in the thermal energy storage module 130 by heating the phase-change materials 134.

[0091] The method 200 continues with operating the thermal management system in the selected operating mode (block 230). Particularly, once an operating mode has been selected, the controller 150 operates the heat pump system 100 in the selected operating mode to heat or cool the indoors environment and/or to charge or discharge the thermal energy storage module 130.

[0092] When the normal heating mode 410 is selected, the heat pump system 100 operates to draw thermal energy from the outdoors environment and release the thermal energy into the indoors environment, thereby heating the indoors environment. The controller 150 operates the compressor 116 to compress the refrigerant, increasing its temperature and pressure. The higher-temperature, higher-pressure refrigerant from the compressor 116 is circulated through the inside air heat exchanger 108, where it releases heat to warm the inside air 110. Next, the refrigerant passes through the expander 120, where it undergoes a reduction in pressure and temperature. The lower-temperature, lower-pressure refrigerant from the expander 120 is circulated through the outside air heat exchanger 104, where it absorbs heat from the outside air, even in cold conditions. The refrigerant then returns to the compressor 116 to repeat the cycle.

[0093] When the normal cooling mode 412, the heat pump system 100 operates to draw thermal energy from the indoors environment and release the thermal energy into the outdoors environment, thereby cooling the indoors environment. The controller 150 operates the compressor 116 to compress the refrigerant, increasing its temperature and pressure. The higher-temperature, higher-pressure refrigerant from the compressor 116 is circulated through the outside air heat exchanger 104, where it releases heat into the outside air 106. Next, the refrigerant passes through the expander 120, where it undergoes a reduction in pressure and temperature. The lower-temperature, lower-pressure refrigerant from the expander 120 is circulated through the inside air heat exchanger 108, where it absorbs heat from the inside air 110. The refrigerant then returns to the compressor 116 to repeat the cycle.

[0094] When the discharging-heating mode 408 is selected, the heat pump system 100 operates to draw thermal energy from the thermal energy storage module 130 and release the thermal energy into the indoors environment, thereby heating the indoors environment and discharging the thermal energy storage module 130. Particularly, the controller 150 operates the plurality of switchable valves 140 such that the refrigerant from the inside air heat exchanger 108, which has cooled from releasing heat into the inside air 110 is circulated through the expander 120. The lower-temperature, lower-pressure refrigerant from the expander 120 is circulated through the TES heat exchanger 138, where it absorbs heat from the phase-change materials 134, thereby releasing thermal energy for heating. The controller 150 operates the plurality of switchable valves 140 such that the refrigerant from the TES heat exchanger 138 is circulated through the compressor 116. The controller 150 operates the compressor 116 to compress the refrigerant, increasing its temperature and pressure. The higher-temperature, higher-pressure refrigerant from the compressor 116 then returns to the inside air heat exchanger 108 to repeat the cycle.

[0095] When the charging-heating mode 416 is selected, the heat pump system 100 operates to draw thermal energy from the outdoors environment and store the thermal energy in the thermal energy storage module 130, thereby charging the thermal energy storage module 130. Particularly, the controller 150 operates the plurality of switchable valves 140 such that the refrigerant from the outside air heat exchanger 104, which has heated from absorbing heat from the outside air 106 is circulated through the compressor 116. The controller 150 operates the compressor 116 to compress the refrigerant, increasing its temperature and pressure. The higher-temperature, higher-pressure refrigerant from the compressor 116 is circulated through the TES heat exchanger 138, where it releases heat into the phase-change materials 134, thereby storing thermal energy for heating. The controller 150 operates the plurality of switchable valves 140 such that the refrigerant from the TES heat exchanger 138 is circulated through the expander 120. The lower-temperature, lower-pressure refrigerant from the expander 120 is circulated through the outside air heat exchanger 104, where it absorbs heat from the outside air 106. The refrigerant then returns to the compressor 116 to repeat the cycle.

[0096] When the charging-cooling mode 434 is selected, the heat pump system 100 operates to draw thermal energy from the indoors environment and store the thermal energy in the thermal energy storage module 130, thereby cooling the indoors environment and charging the thermal energy storage module 130. Particularly, the controller 150 operates the plurality of switchable valves 140 such that the refrigerant from the inside air heat exchanger 108, which has heated from absorbing heat from the inside air 110, is circulated through the compressor 116. The controller 150 operates the compressor 116 to compress the refrigerant, increasing its temperature and pressure. The higher-temperature, higher-pressure refrigerant from the compressor 116 is circulated through the TES heat exchanger 138, where it releases heat into the phase-change materials 134, thereby storing thermal energy for cooling. The controller 150 operates the plurality of switchable valves 140 such that the refrigerant from the TES heat exchanger 138 is circulated through the expander 120. The lower-temperature, lower-pressure refrigerant from the expander 120 then returns to the inside air heat exchanger 108 to repeat the cycle.

[0097] When the discharging-cooling mode 436 is selected, the heat pump system 100 operates to draw thermal energy from the thermal energy storage module 130 and release the thermal energy into the outdoors environment, thereby discharging the thermal energy storage module 130. Particularly, the controller 150 operates the plurality of switchable valves 140 such that the refrigerant from the TES heat exchanger 138, which has heated from absorbing heat from the phase-change materials 134, is circulated through the compressor 116. The controller 150 operates the compressor 116 to compress the refrigerant, increasing its temperature and pressure. The higher-temperature, higher-pressure refrigerant from the compressor 116 is circulated through the outside air heat exchanger 104, where it releases heat into the outside air 106, thereby releasing thermal energy for cooling. The controller 150 operates the plurality of switchable valves 140 such that the refrigerant from the outside air heat exchanger 104 is circulated through the expander 120. The lower-temperature, lower-pressure refrigerant from the expander 120 is circulated through the TES heat exchanger 138, where it absorbs heat from the phase-change materials 134. The refrigerant then returns to the compressor 116 to repeat the cycle.

[0098] Finally, in a standby mode, the heat pump system 100 is not actively heating or cooling but remains ready to engage when needed.

[0099] Embodiments within the scope of the disclosure may also include non-transitory computer-readable storage media or machine-readable medium for carrying or having computer-executable instructions (also referred to as program instructions) or data structures stored thereon. Such non-transitory computer-readable storage media or machine-readable medium may be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such non-transitory computer-readable storage media or machine-readable medium can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code means in the form of computer-executable instructions or data structures. Combinations of the above should also be included within the scope of the non-transitory computer-readable storage media or machine-readable medium.

[0100] Computer-executable instructions include, for example, instructions and data which cause a general-purpose computer, special purpose computer, or special purpose processing device to perform a certain function or group of functions. Computer-executable instructions also include program modules that are executed by computers in stand-alone or network environments. Generally, program modules include routines, programs, objects, components, and data structures, etc. that perform particular tasks or implement particular abstract data types. Computer-executable instructions, associated data structures, and program modules represent examples of the program code means for executing steps of the methods disclosed herein. The particular sequence of such executable instructions or associated data structures represents examples of corresponding acts for implementing the functions described in such steps.

[0101] While the disclosure has been illustrated and described in detail in the drawings and foregoing description, the same should be considered as illustrative and not restrictive in character. It is understood that only the preferred embodiments have been presented and that all changes, modifications and further applications that come within the spirit of the disclosure are desired to be protected.