Systems and methods for providing domestic hot water

Abstract

This invention provides a system for providing domestic hot water and a method of using the system. The system includes: a heat pump; a tap water supply device; a heat exchanger establishing a thermal connection between a fluid line exiting the tap water supply device and a fluid line exiting the heat pump; a thermal energy storage device connected to the heat pump; and a controller having different operating modes and configured to select between these operating modes and control the heat pump based on the selected operating mode. In a first operating mode, heat energy is supplied from the heat pump to the thermal energy storage device but not to the heat exchanger, while in a second operating mode, heat energy is supplied from the heat pump to the heat exchanger. The configuration of the controller for switching to the second operating mode allows the system and method to continuously provide domestic hot water, i.e., there is no downtime.

Description

Technical Field

[0001] This invention provides a system for providing domestic hot water and a method of using the system. The system includes: a heat pump; a tap water supply device; a heat exchanger establishing a thermal connection between a fluid line leaving the tap water supply device and a fluid line leaving the heat pump; a thermal energy storage device connected to the heat pump; and a controller having different operating modes and configured to select between these operating modes and control the heat pump based on the selected operating mode. In a first operating mode, heat energy is supplied from the heat pump to the thermal energy storage device but not to the heat exchanger, while in a second operating mode, heat energy is supplied from the heat pump to the heat exchanger. The controller configuration for switching to the second operating mode allows the system and method to continuously provide domestic hot water, i.e., there is no downtime. Background Technology

[0002] Combined boilers have a high heat output, with even the smaller models providing 25 kW of heat output for domestic hot water (DHW), whereas heating tap water from 10°C to 40°C requires approximately 15 to 20 kW (for a typical D supply flow rate of 7-10 liters / minute). Therefore, combined boilers can directly provide domestic hot water without a thermal energy storage (TES) device.

[0003] If the system providing domestic hot water does not have a combined boiler but only a residential heat pump with a heat output of approximately 4 to 10 kW, the residential heat pump alone is insufficient to directly heat domestic hot water (DHW) within the heat pump itself. Therefore, in these systems, a thermal energy storage device, particularly a domestic hot water thermal energy storage device (DHW-TES), is required to provide domestic hot water. However, once the domestic hot water thermal energy storage device is completely emptied, the system can no longer provide hot water, and it takes approximately two hours to completely refill the domestic hot water thermal energy storage device.

[0004] US 9,581,340 B2 discloses a preheating tank, a heat exchanger operatively connected to the preheating tank, and the preheating tank receiving water from a distribution subsystem. The controller has a first mode and a second mode, in which fluid is directed through the heat exchanger to transfer heat to the preheating tank, and in the second mode, fluid is directed through the evaporator of a refrigerator to transfer heat to a refrigerant. A water storage tank is connected to the preheating tank to receive water from the preheating tank and is also connected to the condenser of the refrigerator, such that heat discharged from the condenser is transferred to the contents of the water storage tank.

[0005] US 2006 / 0196955 A1 discloses a domestic water tank preheating system for preheating domestic water in a domestic water tank and provides a water-saving system for limiting the waste of clean but warm water.

[0006] GB 2464162 A discloses an auxiliary heat exchange unit for use in conjunction with a hot water tank of a hot water supply device, and includes a first water tank, a second water tank and a central water tank.

[0007] WO 2020 / 227216 A1 discloses a domestic hot water preheater that can be used to supply domestic hot water to buildings and / or preheat cold return water of space heating systems.

[0008] In existing heat pump systems, the heat pump and domestic hot water are separate because tap water enters directly into the domestic hot water thermal energy storage device and is heated within it. Furthermore, in existing heat pump systems, the heating of the domestic hot water thermal energy storage device is independent of domestic hot water demand, and all heat energy from the heat pump is directed to the domestic hot water thermal energy storage device for charging.

[0009] The problem with existing systems is that when the domestic hot water thermal energy storage device (DHW-TES) is completely emptied, the system can no longer provide hot water, and it may take several hours before the storage device is refilled. In other words, the system is unable to provide hot water for a considerable period, until the storage device is sufficiently heated to heat tap water to the desired temperature. This results in a significant downtime when providing domestic hot water. Summary of the Invention

[0010] Therefore, it can be seen that the purpose of this application is to provide a system and method that does not suffer from the disadvantages of existing systems and methods. Specifically, using the system and method, hot water should be available without interrupting the power supply when providing domestic hot water.

[0011] The objective is achieved by an apparatus having the features of technical solution 1 and a method having the features of technical solution 9. Dependent technical solutions describe advantageous embodiments of the invention.

[0012] According to the present invention, a system for providing domestic hot water is provided, the system comprising:

[0013] a) Heat pump;

[0014] b) Tap water supply system;

[0015] c) A heat exchanger that establishes a thermal connection between a fluid line exiting the water supply unit and a fluid line exiting the heat pump;

[0016] d) A thermal energy storage device connected to the heat pump;

[0017] e) First operating mode, in which thermal energy is supplied from the heat pump to the thermal energy storage device, but not to the heat exchanger;

[0018] f) A second operating mode, in which thermal energy is supplied from the heat pump to the heat exchanger; and

[0019] g) A controller configured to select at least between a first operating mode and a second operating mode, and configured to control the heat pump based on the selected operating mode.

[0020] The system according to the invention allows for the provision of domestic hot water without shutdown and allows for increased domestic hot water output capacity. This is because the system according to the invention can switch between a first operating mode and a second operating mode, thereby linking the heat pump operation to the level of domestic hot water demand. If there is no demand for domestic hot water, the system can switch to the first operating mode. If there is (high) demand for domestic hot water, the system can switch to the second operating mode.

[0021] In the first operating mode (i.e., when there is no demand for domestic hot water), the controller of the system controls the heat pump to provide heat energy from the heat pump to the thermal energy storage device, but not to the heat exchanger; that is, the controller heats the thermal energy storage device. In the second operating mode (i.e., when the demand for domestic hot water is high), the controller of the system controls the heat pump to provide heat energy from the heat pump to the heat exchanger of the system; that is, the controller heats the tap water in the heat exchanger. This heating can be preheating of the tap water before it enters the thermal energy storage device of the system, or it can be postheating of the tap water after it leaves the thermal energy storage device. Therefore, in the system according to the invention (used in the method according to the invention), the heat exchanger can be located upstream or downstream of the thermal energy storage device.

[0022] It is evident that in the second operating mode, especially during periods of high demand for domestic hot water, the additional heating of tap water via the heat exchanger reduces the heating load on the heat storage device. In other words, a larger volume of domestic hot water at the target temperature can be provided, or conversely, domestic hot water at the target temperature can be provided for a longer period of time, thereby eliminating downtime.

[0023] In short, the second operating mode has the following advantages:

[0024] —The domestic hot water output of the thermal energy storage device can be increased because the total instantaneous heat load required is distributed between the heat pump and the thermal energy storage device;

[0025] —Since the heat pump is already running and does not require start-up time (including infrequent reheat cycles), the thermal energy storage device can be reheated more quickly after a large amount of domestic hot water is discharged.

[0026] —During the second operating mode, a higher heat pump efficiency (coefficient of performance) can be achieved because there is a low temperature rise between the ambient air temperature and the preheated tap water outlet temperature.

[0027] —If the thermal energy storage device is full and a large demand for domestic hot water is predicted based on user behavior (e.g., all family members showering in the morning), the downtime of domestic hot water supply can be reduced.

[0028] The controller of the system can be configured to allow the heated tap water to flow from the heat exchanger into the thermal energy storage device in the second operating mode. Preferably, the flow of the heated tap water is allowed such that the thermal energy storage device transfers heat energy to the heated tap water (equivalent to further heating the tap water, for example, if the thermal energy storage device is a phase change material thermal energy storage device), or the thermal energy of the heated tap water is transferred to the thermal energy storage device (equivalent to charging the thermal energy storage device, for example, if the thermal energy storage device is a water tank).

[0029] The controller of the system can be configured to switch to the first operating mode if there is no urgent need for domestic hot water and the thermal energy storage device is below a preset threshold.

[0030] Furthermore, the controller of the system can be configured to switch to the second operating mode if the urgent demand for domestic hot water is high and the heat pump is operating or not operating, or if the demand for domestic hot water is low and the heat pump is operating.

[0031] The system may include a third operating mode in which no heat energy is supplied from the heat pump to the heat storage device and the heat exchanger. In the third operating mode, the system is configured to provide domestic hot water solely through the heat energy stored in the heat storage device; that is, only the heat storage device is used to heat tap water into domestic hot water. The controller is preferably configured to switch to the third operating mode if the urgent demand for domestic hot water is low and / or if the heat storage device is at or above a preset threshold and the heat pump must not operate. In the third operating mode (when the demand for domestic hot water is low), the controller of the system controls the heat pump so that no heat energy is supplied from the heat pump to the heat storage device or to the system's heat exchanger; that is, the controller ensures that tap water is heated solely through the heat energy stored in the heat storage device, thereby emptying the heat storage device.

[0032] The system may also include a fluid flow detection sensor adapted to detect the volumetric flow rate of fluid from the thermal energy storage device to the domestic hot water outlet of the system.

[0033] Furthermore, the system may also include a resistance heater for heating the water in the tap water supply unit. The controller is preferably configured to activate the resistance heater if there is a high and urgent demand for domestic hot water. The resistance heater allows for further heating of the tap water and allows for a faster response to heating demands than the heat pump, which requires time to operate at full capacity. The resistance heater can be located upstream or downstream of the thermal energy storage unit. The upstream location of the thermal energy storage unit has the advantage that the resistance heater can help to charge (utilize) the thermal energy storage unit. Additionally, the resistance heater can be located upstream or downstream of the heat exchanger. Preferably, the resistance heater is located downstream of the heat exchanger and upstream of the thermal energy storage unit. The resistance heater and the heat pump can also work together to provide warm drinking water at a temperature that is not too cold for the user. If the thermal energy storage unit is completely emptied and there is still a high demand for domestic hot water, this allows bypassing the thermal energy storage unit to avoid emptying it or provides another measure to avoid a shutdown.

[0034] The system may include a mechanism for heating water in the tap water supply unit using energy recovered from wastewater. The mechanism is preferably located upstream of the heat exchanger in the system.

[0035] The system may further include a heat charge status device configured to determine the heat charge status of the thermal energy storage device. Preferably, the controller is configured to control the heat pump based on the heat charge status determined by the heat charge status device. Furthermore, the controller may be configured to switch to a first operating mode if the determined heat charge status of the thermal energy storage device is below a preset threshold. Furthermore, the controller may be configured to switch to a second operating mode if the determined heat charge status of the thermal energy storage device is below a preset threshold. Furthermore, the controller may be configured to switch to a third operating mode if the heat charge status of the thermal energy storage device is at or above a preset threshold, in which no heat energy is supplied from the heat pump to the thermal energy storage device and the heat exchanger.

[0036] The controller may be configured to switch to the second operating mode if the hot water consuming device has a demand for a large amount of domestic hot water. The hot water consuming device is preferably configured to notify the controller of the demand for a large amount of hot water. The hot water consuming device is particularly preferably selected from the group consisting of a kitchen sink, bathtub, washing machine, dishwasher, and combinations thereof.

[0037] Furthermore, the controller can be configured to switch to the second operating mode if a domestic hot water demand forecast predicts a large demand for domestic hot water. Preferably, the controller is configured to implement the forecast.

[0038] Furthermore, the controller can be configured to switch to the second operating mode if the volumetric flow rate from the thermal energy storage device to the system's domestic hot water outlet reaches a certain threshold and the system's domestic hot water outlet is associated with a large domestic hot water outlet. The volumetric flow rate is preferably detected by a fluid flow detection sensor of the system, configured to notify the controller of the detected volumetric flow rate. The fluid flow detection sensor is particularly preferably selected from the group consisting of a flow meter, a pressure sensor, a temperature sensor, and combinations thereof.

[0039] Furthermore, the controller can be configured to switch to the second operating mode if a direct user input notifies the controller of a large demand for domestic hot water. The direct user input is preferably detected by an input device of the system, which is configured to notify the controller of the large demand for domestic hot water.

[0040] In a preferred embodiment, the thermal energy storage device is a phase change material thermal energy storage device (PCM-TES). The PCM-TES may include an embedded heat exchanger that facilitates the transfer of heat from the heat pump to the PCM-TES. From an energy perspective, the PCM-TES is advantageous as a thermal energy storage device. The PCM-TES stores most of its energy by utilizing the heat of fusion of the phase change material (PCM), meaning that almost all the energy is stored and released at the melting temperature of the PCM (e.g., 50°C). Therefore, water entering at a higher inlet temperature will result in a lower heat discharge flow rate from the PCM to the water. A lower discharge flow rate allows for an increase in the amount of water that can be extracted from the heat stored in the PCM at 50°C.

[0041] Alternatively, the thermal energy storage device may be a water tank, preferably a water tank containing encapsulated phase change material.

[0042] According to the present invention, a method for providing domestic hot water is provided, the method comprising the following steps:

[0043] a) Setting up a system, the system comprising:

[0044] Heat pump;

[0045] tap water supply equipment;

[0046] A heat exchanger that establishes a thermal connection between a fluid line exiting the tap water supply device and a fluid line exiting the heat pump;

[0047] A thermal energy storage device, wherein the thermal energy storage device is connected to the heat pump;

[0048] In the first operating mode, thermal energy is supplied from the heat pump to the thermal energy storage device, but not to the heat exchanger.

[0049] A second operating mode, in which thermal energy is supplied from the heat pump to the heat exchanger; and

[0050] A controller configured to select between at least a first operating mode and a second operating mode.

[0051] b) The heat pump is controlled by the controller based on the selected operating mode.

[0052] Using the method described in this invention, domestic hot water can be provided without shutting down the system, and the output capacity of domestic hot water can be increased.

[0053] In the method, the controller may be configured to allow heated tap water to flow from the heat exchanger into the thermal energy storage device in the second operating mode. Preferably, the heated tap water is allowed to flow from the heat exchanger into the thermal energy storage device, such that the thermal energy of the thermal energy storage device is transferred to the heated tap water or the thermal energy of the heated tap water is transferred to the thermal energy storage device.

[0054] In the method, the controller may be configured to switch to the first operating mode if there is no urgent need for domestic hot water and the thermal energy storage device is below a preset threshold.

[0055] Furthermore, in the method, the controller may be configured to switch to the second operating mode if the urgent demand for domestic hot water is high and the heat pump is operating or not operating, or if the demand for domestic hot water is low and the heat pump is operating.

[0056] The system provided in the method may include a third operating mode in which no heat energy is supplied from the heat pump to the heat storage device and the heat exchanger. In the third operating mode, the system is configured to provide domestic hot water solely through the heat energy stored in the heat storage device; that is, only the heat storage device is used to heat tap water into domestic hot water. In the method, the controller is preferably configured to switch to the third operating mode if the urgent demand for domestic hot water is low and / or if the heat storage device is at or above a preset threshold and the heat pump must not operate.

[0057] The system provided in the method may further include a fluid flow detection sensor adapted to detect the volumetric flow rate of fluid from the thermal energy storage device to the domestic hot water outlet of the system.

[0058] Furthermore, the system provided in the method may further include a resistance heater for heating the water in the tap water supply device. In the method, the controller is preferably configured to activate the resistance heater if there is a high demand for domestic hot water. The resistance heater allows for further heating of the tap water and allows for a faster response to heating demands than the heat pump, which requires time to operate at full capacity. The resistance heater can be located upstream or downstream of the thermal energy storage device. The upstream location of the thermal energy storage device has the advantage that the resistance heater can help to charge (utilize) the thermal energy storage device. Additionally, the resistance heater can be located upstream or downstream of the heat exchanger. Preferably, the resistance heater is located downstream of the heat exchanger and upstream of the thermal energy storage device. The resistance heater and the heat pump can also work together to provide warm drinking water at a temperature that the user feels is not too cold. If the thermal energy storage device is completely emptied and there is still a high demand for domestic hot water, this allows bypassing the thermal energy storage device to avoid emptying it or provides another measure to avoid shutdown.

[0059] The system provided in the method may include a mechanism for heating water in the tap water supply device using energy recovered from wastewater. The mechanism is preferably located upstream of the heat exchanger in the system of the method.

[0060] The system provided in the method may further include a heat charge state device configured to determine the heat charge state of the thermal energy storage device. In the method, the controller is preferably configured to control the heat pump based on the heat charge state determined by the heat charge state device. Furthermore, in the method, the controller is preferably configured to switch to a first operating mode if the determined heat charge state of the thermal energy storage device is below a preset threshold. Furthermore, in the method, the controller is preferably configured to switch to a second operating mode if the determined heat charge state of the thermal energy storage device is below a preset threshold. Furthermore, in the method, the controller is preferably configured to switch to a third operating mode if the heat charge state of the thermal energy storage device is at or above a preset threshold, in which no heat energy is supplied from the heat pump to the thermal energy storage device and the heat exchanger.

[0061] In the method, the controller is configured to switch to the second operating mode if the hot water consuming device has a demand for a large amount of domestic hot water. In the method, the hot water consuming device is preferably configured to notify the controller of the demand for a large amount of hot water. The hot water consuming device is particularly preferably selected from the group consisting of a kitchen sink, bathtub, washing machine, dishwasher, and combinations thereof.

[0062] Furthermore, in the method, the controller can be configured to switch to the second operating mode if the domestic hot water demand forecast predicts a large demand for domestic hot water. Preferably, in the method, the controller is configured to implement the forecast.

[0063] Furthermore, in the method, the controller may be configured to switch to the second operating mode if the volumetric flow rate from the thermal energy storage device to the system's domestic hot water outlet reaches a certain threshold and the system's domestic hot water outlet is associated with a large domestic hot water outlet. The volumetric flow rate is preferably detected by a fluid flow detection sensor of the system, configured to notify the controller of the detected volumetric flow rate. The fluid flow detection sensor may be selected from the group consisting of a flow meter, a pressure sensor, a temperature sensor, and combinations thereof.

[0064] Furthermore, in the method, the controller is configured to switch to the second operating mode if a direct user input notifies the controller of a large demand for domestic hot water. The direct user input is preferably detected by an input device of the system, which is configured to notify the controller of the demand for a large amount of domestic hot water.

[0065] In a preferred embodiment, the thermal energy storage device of the system provided in the method is a phase change material thermal energy storage device. The phase change material thermal energy storage device preferably includes an embedded heat exchanger that facilitates the transfer of heat from the heat pump to the phase change material thermal energy storage device.

[0066] Alternatively, the thermal energy storage device may be a water tank, preferably a water tank containing encapsulated phase change material. Attached Figure Description

[0067] Figure 1 The diagram schematically illustrates simple rule-based control of the controller of the system and method according to the present invention.

[0068] Figure 2 The first system according to the invention is illustrated schematically.

[0069] Figure 3 Another system according to the invention is schematically shown in its first operating mode (heat charging mode).

[0070] Figure 4 schematically shown Figure 3 The system shown is in the second operating mode (preheated water outlet mode).

[0071] Figure 5Another system according to the invention is schematically shown in a second operating mode (post-heated water outlet mode). Detailed Implementation

[0072] Referring to the following figures and embodiments, the subject matter according to the invention is intended to be described in more detail, but it is not intended to limit the subject matter to the specific embodiments shown herein.

[0073] Figure 1 The diagram schematically illustrates simple rule-based control of a controller for a system and method according to the present invention. The controller is configured to determine whether the system should operate in a first operating mode (heating mode) or a second operating mode (preheating mode). In this embodiment, the controller is also configured to determine whether the system should operate in a third operating mode (cooler tap water heated only by the domestic hot water thermal energy storage device). Preheating can be initiated when the urgent demand for domestic hot water is high, or if the urgent demand for hot water is low and the heat pump is already running. When the domestic hot water (DHW) demand has ceased, the controller can return to the first operating mode (heating mode). Furthermore, if a large domestic hot water demand is detected or the state of charge (SOC) of the thermal energy storage device (TES) drops below a minimum threshold, the controller initiates the domestic hot water preheating mode.

[0074] Figure 2 A first system according to the present invention is schematically illustrated. In this embodiment, the thermal energy storage device is a phase change material thermal energy storage device (PCM-TES). Domestic hot water leaving the tap water supply device 2 flows through a fluid line and passes through a heat exchanger 3, where the domestic hot water can receive heat energy from the fluid line leaving the heat pump 1. En route to the thermal energy storage device 4 (in this case, a domestic hot water thermal energy storage device), the preheated tap water can be further heated by a resistance heater 13. In the thermal energy storage device, the preheated tap water is further heated into domestic hot water 10, which can flow to a kitchen sink 14 or a bathtub 15. The system controller 5 is configured to control the heat pump 1. The illustrated system also includes a charging status device 6 and a flow detection sensor 7, the charging status device 6 being configured to determine the charging status of the thermal energy storage device 4. To guide the flow of tap water, the system also includes a switching valve 12, which allows tap water to flow via the resistance heater 13 through the heat exchanger 3 to the thermal energy storage device 4, or to the local space heating system 8. The indoor unit 9 includes the heat exchanger 3, the resistance heater 13, the controller 5, and the switching valve.

[0075] Figure 3Another system according to the invention is schematically shown in a first operating mode (heating mode). In this system, the thermal energy storage device 4 is a water tank. Domestic water leaving the tap water supply device 2 flows through the heat pump 1 in a fluid pipeline, where the domestic water can receive heat energy from the heat pump 1. In this first operating mode, there is no discharge from the thermal energy storage device 4 (see the larger line thickness), that is, no domestic hot water 10 is supplied to the kitchen sink 14 and / or bathtub 15. Furthermore, no tap water enters the thermal energy storage device 4, but water is actively drawn from the thermal energy storage device 4 through a second pipeline, flowing successively through the heat exchanger 3 and the resistance heater 13 before returning to the thermal energy storage device. The controller 5 of the system is configured to control the heat pump 1. The system shown also includes a heating state device 6 and a flow detection sensor 7, the heating state device 6 being configured to determine the heating state of the thermal energy storage device 4. To guide the flow of tap water, the system also includes a switching valve 12. The heating cylinder unit 11 for domestic hot water includes the heat exchanger 3, the resistance heater 13, the controller 5, and the switching valve.

[0076] Figure 4 schematically shown Figure 3 The system shown is in the second operating mode (preheated water output mode). Domestic water leaving the tap water supply device 2 flows through the heat exchanger 3 in a fluid pipeline, where it receives heat energy from the fluid pipeline leaving the heat pump 1. En route to the heat energy storage device 4 (in this case, a water tank), the preheated tap water transfers heat to the heat energy storage device 4. Water heated to domestic hot water 10 in the heat energy storage device 4 can flow to the kitchen sink 14 or bathtub 15. The controller 5 of the system is configured to control the heat pump 1. The system also includes a charging status device 6 and a flow detection sensor 7, the charging status device 6 being configured to determine the charging status of the heat energy storage device 4. To guide the flow of tap water, the system also includes a switching valve 12. The hot water tank unit 11 includes the heat exchanger 3, the resistance heater 13, the controller 5, and the switching valve.

[0077] Figure 5 Another system according to the invention is schematically shown in a second operating mode (post-heated water outlet mode). For clarity, details are omitted. Figures 2 to 4Some components of the system shown are illustrated. In this embodiment, tap water leaving the thermal energy storage device 4 of the system is heated by the heat exchanger 3, which receives heat energy from the heat pump 1 and is located downstream of the thermal energy storage device 4. This allows domestic hot water 10 at the target temperature to be supplied to the kitchen sink 14 and / or bathtub 15 even if the thermal energy storage device has a low heating capacity or is completely drained.

[0078] Example 1—Exemplary use of the system and method

[0079] For example, a shower requires a water flow rate of approximately 7 liters per minute (LPM). To provide domestic hot water for the shower, cooler tap water enters the heat exchanger at a temperature of 10°C, where it is heated to 20°C by a 5kW source from the heat pump, or further heated to 26°C by an additional 3kW source from the resistance heater. The preheated tap water is then further heated from 26°C to an outlet temperature of 40°C in the domestic hot water thermal energy storage device.

[0080] This results in a discharge capacity of 6.8 kW for the domestic hot water thermal energy storage device, which is significantly lower than the 15 kW required without a preheating mode.

[0081] Therefore, if the heating mode (second operating mode) is applied, the amount of domestic hot water supplied by the domestic hot water thermal energy storage device can be doubled. Furthermore, even after the domestic hot water thermal energy storage device is completely emptied, a shower can still obtain warm water at 26°C.

[0082] Example 2—First Embodiment ( Figure 2 )

[0083] Figure 2 A first embodiment of the system and method according to the present invention is shown. In this embodiment, the thermal energy storage device is a phase change material thermal energy storage device (PCM-TES).

[0084] First operating mode (heating mode of phase change material thermal energy storage device)

[0085] The first operating mode refers to a mode in which the heat pump delivers heat to the phase change material thermal energy storage device (preferably via heat delivery to a heat exchanger embedded in the phase change material thermal energy storage device), but does not deliver heat to the water flowing through the heat exchanger, which establishes a thermal connection between the fluid line leaving the tap water supply device and the fluid line leaving the heat pump.

[0086] If there is no urgent need for domestic hot water and the phase state (SOC) of the phase change material thermal energy storage device is below a threshold, the first operating mode can be activated.

[0087] Second operating mode (preheated water output mode)

[0088] The second operating mode refers to a mode in which the heat pump delivers heat to the water flowing through the heat exchanger, which establishes a thermal connection between the fluid line exiting the tap water supply device and the fluid line exiting the heat pump. The tap water, heated in the heat exchanger, is then delivered to the phase change material thermal energy storage device, where it is further heated to its final temperature.

[0089] For example in Figure 2 As can be seen, tap water from the water supply device enters the heat exchanger (which establishes a thermal connection between the fluid line leaving the water supply device and the fluid line leaving the heat pump), and is heated in the heat exchanger by heat from the heat pump (the fluid line of the heat pump's primary circuit). An optional resistance heater can further heat the tap water after it leaves the heat exchanger. The preheated tap water enters the phase change material thermal energy storage device (preferably a heat exchanger embedded in the phase change material thermal energy storage device) at an intermediate temperature and is heated to its desired final temperature by the phase change material thermal energy storage device.

[0090] The second operating mode can be activated, for example, when the following conditions are met:

[0091] - The thermal energy storage device's charging state drops below a threshold, wherein the charging state is preferably detected by a charging state device of the system, the charging state device being configured to notify the controller of the detected charging state; and / or

[0092] - A hot water consuming device has a demand for a large amount of domestic hot water, wherein the hot water consuming device is preferably configured to notify the controller of the demand for a large amount of hot water, wherein the hot water consuming device is particularly preferably selected from the group consisting of a bathtub, a washing machine, and combinations thereof; and / or

[0093] - Domestic hot water demand forecasting predicts a large demand for domestic hot water, wherein, preferably, the controller is configured to implement the forecast; and / or

[0094] - The volumetric flow rate from the thermal energy storage device (4) to the domestic hot water outlet reaches a certain threshold, wherein the volumetric flow rate is preferably detected by a fluid flow detection sensor of the system, the fluid flow detection sensor being configured to notify the controller of the detected volumetric flow rate, wherein the fluid flow detection sensor is particularly preferably selected from the group consisting of a flow meter, a pressure sensor, a temperature sensor, and combinations thereof; and / or

[0095] - Direct user input notification of a large demand for domestic hot water, wherein the direct user input is preferably detected by the input device of the system, the input device being configured to notify the controller of the large demand for domestic hot water.

[0096] Third operating mode (normal water output mode)

[0097] The third operating mode refers to a mode in which the heat pump neither supplies heat to the phase change material thermal energy storage device nor to the heat exchanger, which establishes a thermal connection between the fluid line leaving the tap water supply device and the fluid line leaving the heat pump. In this third operating mode, the heat pump neither supplies heat energy to the tap water (via the heat exchanger) nor to the phase change material thermal energy storage device (i.e., no charging of the phase change material thermal energy storage device occurs).

[0098] For example in Figure 2 As can be seen, tap water from the water supply unit enters the heat exchanger (which establishes a thermal connection between the fluid line leaving the water supply unit and the fluid line leaving the heat pump) and is not heated in the heat exchanger. An optional resistance heater is off. The unheated tap water enters the phase change material thermal energy storage device (preferably embedded in the heat exchanger) at its original temperature and is heated by the phase change material thermal energy storage device (separately) to its desired final temperature.

[0099] Since all the energy input to the tap water is provided by the phase change material thermal energy storage device, the third operating mode is advantageous if only a small amount of domestic hot water output is required, for example, less than the start-up time required by the heat pump. This configuration can also be advantageous if other control decisions prohibit the heat pump's domestic hot water circulation (e.g., due to a lack of inexpensive renewable energy).

[0100] Example 3—Second Embodiment ( Figure 3 and Figure 4 )

[0101] Figure 3 and Figure 4 A second embodiment of the system and method according to the present invention is shown. In this embodiment, the thermal energy storage device is a water tank.

[0102] First operating mode (water tank heating mode)

[0103] The first operating mode is in Figure 3The diagram illustrates a mode in which the heat pump delivers heat to the water tank but not to the tap water flowing through the heat exchanger, which establishes a thermal connection between the fluid line leaving the tap water supply and the fluid line leaving the heat pump.

[0104] If there is no urgent need for domestic hot water and the heating capacity of the water storage tank is below the threshold, the first operating mode can be activated.

[0105] Second operating mode (preheated water output mode)

[0106] The second operating mode is in Figure 4 The diagram illustrates a mode in which the heat pump delivers heat to tap water flowing through the heat exchanger, which establishes a thermal connection between the fluid line exiting the tap water supply and the fluid line exiting the heat pump. The tap water, heated in the heat exchanger, is then delivered to a storage tank, where it transfers heat to the water tank.

[0107] For example in Figure 4 As can be seen, tap water from the water supply device enters the heat exchanger (which establishes a thermal connection between the fluid line leaving the water supply device and the fluid line leaving the heat pump), and is heated in the heat exchanger by heat from the fluid line of the heat pump (the primary circuit of the heat pump). An optional resistance heater can further heat the tap water after it leaves the heat exchanger. The preheated tap water enters the storage tank and transfers heat to it. The preheated tap water is delivered to the storage tank in a non-mixed manner. For this purpose, as... Figure 3 and Figure 4 As shown, it is advantageous if the inlet for guiding the preheated tap water into the water tank is located near the bottom of the tank. This helps maintain stratification while allowing the water tank to be heated synchronously.

[0108] The second operating mode can be activated, for example, when the following conditions are met (activated by the controller of the system):

[0109] - The heating capacity of the water storage tank (e.g., detected by a temperature sensor) drops below a threshold; and / or

[0110] - At least one device consuming domestic hot water (e.g., a bathtub and / or washing machine) notifies of a large demand for domestic hot water (e.g., notifying the controller of the system); and / or

[0111] - Domestic hot water demand forecasting (e.g., via the system's controller) predicts a large demand for domestic hot water; and / or

[0112] - The volumetric flow rate from the water storage tank to the domestic hot water outlet (e.g., detected by a fluid flow sensor) reaches or exceeds a certain threshold (a suitable fluid flow sensor can be selected from the group consisting of flow meters, pressure sensors, temperature sensors, and combinations thereof); and / or

[0113] - Direct user input (such as a button pressed by a user in the kitchen or bathroom) indicates the need for a large amount of domestic hot water.

[0114] Third operating mode (normal water output mode)

[0115] The third operating mode refers to a mode in which the heat pump neither supplies heat to the water storage tank nor to the heat exchanger, which establishes a thermal connection between the fluid line leaving the tap water supply device and the fluid line leaving the heat pump. In this third operating mode, the heat pump neither supplies heat energy to the tap water (via the heat exchanger) nor to the water storage tank (i.e., no heating of the water storage tank occurs).

[0116] Since all the energy input to the tap water is provided by the storage tank, the third operating mode is advantageous if only a small amount of domestic hot water output is needed, for example, less than the start-up time required by the heat pump. This configuration can also be advantageous if other control decisions prevent the heat pump from circulating domestic hot water (e.g., due to a lack of inexpensive renewable energy).

[0117] Example 4—Third Embodiment (not shown in the figure)

[0118] In the third embodiment, the tap water is additionally heated using energy recovered from the wastewater. For example, this additional heating (not shown in the figure) can be arranged before the tap water enters the heat exchanger and is further heated therein.

[0119] Example 5—Fourth Embodiment ( Figure 5 )

[0120] In the fourth embodiment, in the second operating mode (post-heated water outlet mode), the tap water leaving the thermal energy storage device of the system is further heated by using the heat pump.

[0121] This is possible for a single thermal energy storage device, but it is also possible for more than one thermal energy storage device in the system. In one example, the system includes a first low-temperature phase change material thermal energy storage device with storage capacity at 30-45°C (primarily for space heating), and a second high-temperature phase change material thermal energy storage device with storage capacity at 40-60°C.

[0122] Assuming the second high-temperature phase change material thermal energy storage device is completely emptied and there is a demand for domestic hot water, the heat pump can be used to subsequently heat water from the first low-temperature phase change material thermal energy storage device at an intermediate temperature to a suitable domestic hot water outlet temperature. In other words, tap water will be preheated in the first low-temperature phase change material thermal energy storage device and then subsequently heated by the heat pump.

[0123] List of reference numerals

[0124] 1: Heat pump;

[0125] 2: Tap water supply equipment;

[0126] 3: (Heat exchanger connected to the heat pump and tap water supply system);

[0127] 4: Thermal energy storage devices (e.g., PCM-TES or water storage tanks);

[0128] 5: It is configured as a controller to control the heat pump;

[0129] 6: A charge state device (e.g., a phase state device) configured to determine the charge state of a thermal energy storage device;

[0130] 7: Flow detection sensor;

[0131] 8: Localized space heating system;

[0132] 9: Indoor unit;

[0133] 10: Domestic hot water;

[0134] 11: Heating tank unit for domestic hot water;

[0135] 12: Switching valve;

[0136] 13: Resistance heater;

[0137] 14: Kitchen sink; and

[0138] 15: Bathtub.

Claims

1. System for providing domestic hot water (10), the system comprising: a) a heat pump (1); b) a mains water supply (2); c) a heat exchanger (3) establishing a thermal connection between a fluid line leaving the mains water supply (2) and a fluid line leaving the heat pump (1); d) a thermal energy storage device (4) connected to the heat pump (1); e) a first operating mode in which thermal energy is provided from the heat pump (1) to the thermal energy storage device (4) but not to the mains water flowing through the heat exchanger (3); f) a second operating mode in which thermal energy is provided from the heat pump (1) to the heat exchanger (3); and g) a controller configured to select between at least the first and second operating modes, characterized in that the heat exchanger (3) is located upstream of the thermal energy storage device (4) and the controller is configured to control the heat pump (1) based on the selected operating mode.

2. System according to claim 1, characterized in that the controller is configured to allow heated mains water to flow from the heat exchanger (3) into the thermal energy storage device (4) in the second operating mode, such that: i) thermal energy of the thermal energy storage device (4) is transferred to the heated mains water; or ii) thermal energy of the heated mains water is transferred to the thermal energy storage device (4).

3. System according to claim 1 or 2, characterized in that the controller (5) is configured to: i) switch to the first operating mode if there is no urgent demand for domestic hot water and the thermal energy storage device (4) is below a pre-set threshold of a charging state; and / or ii) switch to the second operating mode if there is a high urgent demand for domestic hot water and the heat pump (1) is running or not running, or if there is a low demand for domestic hot water and the heat pump (1) is running.

4. System according to claim 1 or 2, characterized in that the system comprises a third operating mode in which no thermal energy is provided from the heat pump (1) to the thermal energy storage device (4) and the heat exchanger, wherein the controller (5) is configured to switch to the third operating mode if there is a low urgent demand for domestic hot water and / or if the thermal energy storage device (4) is at or above a pre-set threshold of a charging state and the heat pump (1) is not running.

5. System according to claim 1 or 2, characterized in that the system further comprises: i) a fluid flow detection sensor (7) adapted to detect a volume flow of fluid from the thermal energy storage device (4) to a domestic hot water outlet of the system; and / or ii) an electric resistance heater (13) for heating water of the mains water supply (2), wherein the controller is configured to activate the electric resistance heater (13) if there is a high urgent demand for domestic hot water; and / or iii) a mechanism for heating water of the mains water supply (2) with energy recovered from the wastewater, wherein the mechanism is located upstream of the heat exchanger (3) in the system.

6. System according to claim 1 or 2, characterized in that the system further comprises a charge state device (6) configured to determine a charge state of the thermal energy storage device (4), wherein the controller (5) is configured to: i) control the heat pump (1) based on the charge state determined by the charge state device (6); and / or ii) switch to the first operating mode if the determined charge state of the thermal energy storage device (4) is below a preset threshold; and / or iii) switch to the second operating mode if the determined charge state of the thermal energy storage device (4) is below a preset threshold; and / or iv) switch to a third operating mode in which no thermal energy is provided from the heat pump (1) to the thermal energy storage device (4) and the heat exchanger if the charge state of the thermal energy storage device (4) is at or above a preset threshold.

7. System according to claim 1 or 2, characterized in that the controller (5) is configured to switch to the second operating mode if the following conditions are met: i) a hot water consumer has a demand for a large amount of domestic hot water, wherein the hot water consumer is configured to inform the controller (5) about the demand for a large amount of hot water, wherein the hot water consumer is selected from the group consisting of a kitchen sink (14), a bath tub (15), a washing machine, a dishwasher, and combinations thereof; and / or ii) a domestic hot water demand prediction predicts a demand for a large amount of domestic hot water, wherein the controller (5) is configured to implement the prediction; and / or iii) a volumetric flow from the thermal energy storage device (4) to a domestic hot water outlet of the system reaches above a certain threshold, and the domestic hot water outlet of the system is associated with a large domestic hot water outlet, wherein the volumetric flow is detected by a fluid flow detection sensor (7) of the system, which is configured to inform the controller (5) about the detected volumetric flow, wherein the fluid flow detection sensor is selected from the group consisting of a flow meter, a pressure sensor, a temperature sensor, and combinations thereof; and / or iv) a direct user input informs about a demand for a large amount of domestic hot water, wherein the direct user input is detected by an input device of the system, which is configured to inform the controller (5) about the demand for a large amount of domestic hot water.

8. System according to claim 1 or 2, characterized in that the thermal energy storage device (4) is: i) a phase change material thermal energy storage device, wherein the phase change material thermal energy storage device comprises a heat exchanger embedded therein, which facilitates the transfer of heat from the heat pump (1) to the phase change material thermal energy storage device; or ii) a water storage tank, including a water storage tank encapsulating a phase change material.

9. A method for providing domestic hot water (10), the method comprising the steps of: a) providing a system comprising: a heat pump (1); a mains water supply (2); a heat exchanger (3) establishing a thermal connection between a fluid line leaving the mains water supply (2) and a fluid line leaving the heat pump (1); a thermal energy storage device (4) connected to the heat pump (1); a first operating mode in which thermal energy is provided from the heat pump (1) to the thermal energy storage device (4) but not to the mains water flowing through the heat exchanger (3); a second operating mode in which thermal energy is provided from the heat pump (1) to the heat exchanger (3); and a controller configured to select between at least the first operating mode and the second operating mode, characterized in that the heat exchanger (3) is located upstream of the thermal energy storage device (4) and in that the method comprises the step of: b) controlling the heat pump (1) by the controller based on the selected operating mode.

10. The method according to claim 9, characterized in that in the method the controller is configured to allow in the second operating mode heated mains water to flow from the heat exchanger (3) into the thermal energy storage device (4) so that: i) thermal energy of the thermal energy storage device (4) is transferred to the heated mains water; or ii) thermal energy of the heated mains water is transferred to the thermal energy storage device (4).

11. The method according to claim 9 or 10, characterized in that in the method the controller (5) is configured to: i) switch to the first operating mode if there is no urgent demand for domestic hot water and the thermal charging state of the thermal energy storage device (4) is below a pre-set threshold; and / or ii) switch to the second operating mode if the urgent demand for domestic hot water is high and the heat pump (1) is running or not running, or if the demand for domestic hot water is low and the heat pump (1) is running.

12. The method according to claim 9 or 10, characterized in that the system provided in the method comprises a third operating mode in which no thermal energy is provided from the heat pump (1) to the thermal energy storage device (4) and to the heat exchanger, wherein in the method the controller (5) is configured to switch to the third operating mode if the urgent demand for domestic hot water is low and / or if the thermal charging state of the thermal energy storage device (4) is at or above a pre-set threshold and the heat pump (1) is not to be run.

13. The method according to claim 9 or 10, characterized in that the system provided in the method further comprises: i) a fluid flow detection sensor (7) adapted to detect the volumetric flow of fluid from the thermal energy storage device (4) to a domestic hot water outlet of the system; and / or ii) an electrical resistance heater (13) for heating water of the mains water supply (2), wherein in the method the controller is configured to activate the electrical resistance heater (13) if the demand for domestic hot water is high; and / or iii) a mechanism for heating water of the mains water supply (2) with energy recovered from waste water, wherein the mechanism is located upstream of the heat exchanger (3) in the system.

14. The method according to claim 9 or 10, characterized in that the system provided in the method further comprises a charge state device (6) configured to determine a charge state of the thermal energy storage device (4), wherein in the method the controller (5) is configured to: i) control the heat pump (1) based on the charge state determined by the charge state device (6); and / or ii) switch to the first operating mode if the determined charge state of the thermal energy storage device (4) is below a preset threshold; and / or iii) switch to the second operating mode if the determined charge state of the thermal energy storage device (4) is below a preset threshold; and / or iv) switch to a third operating mode in which no thermal energy is provided from the heat pump (1) to the thermal energy storage device (4) and the heat exchanger if the charge state of the thermal energy storage device (4) is at or above a preset threshold.

15. The method according to claim 9 or 10, characterized in that in the method the controller (5) is configured to switch to the second operating mode if the following conditions are met: i) a hot water consumer has a demand for a large amount of domestic hot water, wherein in the method the hot water consumer is configured to inform the controller (5) about the demand for a large amount of hot water, wherein the hot water consumer is selected from the group consisting of a kitchen sink (14), a bath tub (15), a washing machine, a dishwasher and combinations thereof; and / or ii) a domestic hot water demand prediction predicts a demand for a large amount of domestic hot water, wherein in the method the controller (5) is configured to perform the prediction; and / or iii) a volumetric flow from the thermal energy storage device (4) to a domestic hot water outlet of the system reaches above a certain threshold and the domestic hot water outlet of the system is associated with a large domestic hot water outlet, wherein the volumetric flow is detected by a fluid flow detection sensor (7) of the system, which is configured to inform the controller (5) about the detected volumetric flow, wherein the fluid flow detection sensor is selected from the group consisting of a flow meter, a pressure sensor, a temperature sensor and combinations thereof; and / or iv) a direct user input informs about a demand for a large amount of domestic hot water, wherein the direct user input is detected by an input device of the system, which is configured to inform the controller (5) about the demand for a large amount of domestic hot water.

16. The method according to claim 9 or 10, characterized in that, the thermal energy storage device (4) of the system provided in the method is: i) a phase change material thermal energy storage device, wherein the phase change material thermal energy storage device comprises a heat exchanger embedded therein, which facilitates the transfer of heat from the heat pump (1) to the phase change material thermal energy storage device; or ii) a water storage tank comprising a phase change material encapsulated therein.

Images