Methods and systems and apparatus for supporting reduced energy and water usage

Abstract

A domestic hot water supply system comprises: a cold water inlet (302) for receiving cold water from a header supply; a hot water outlet (304) connected for providing hot water, as needed, to a household hot water outlet activated by a user; a heat exchanger (308) for heating water using a hot fluid received from a hot fluid source (306); an electric heater (326); a heat storage means (342) for storing heat; a circulation pump (320) for pumping water from the heat storage appliance (342) to the heat exchanger (308); and a controller (340) for controlling operation of the system to charge the heat storage appliance (342) with hot water heated by the heat exchanger (308) or hot water heated by the electric heater (326) depending on availability of hot fluid to be provided to the heat exchanger (308) from the hot fluid source (306).

Description

Technical Field

[0001] This disclosure relates in many ways to methods and apparatus for supporting the reduction of energy and water consumption in facilities including hot water supply systems within buildings. Background Technology

[0002] A global drinking water shortage is underway. Water scarcity is now widely reported worldwide, and while one might think this problem only affects “hotspot” countries and continents, this is no longer the case. The European Environment Agency reports that water scarcity, or water tension, is a problem affecting millions of people worldwide, including more than 100 million in Europe. Approximately 88.2% of freshwater use in Europe (drinking and other uses) comes from rivers and groundwater, with the remainder from reservoirs (10.3%) and lakes (1.5%), making these resources highly vulnerable to overexploitation, pollution, and climate change.

[0003] Therefore, there is an urgent need to reduce household water consumption. In Europe, the average person has 144 liters of fresh water available for household consumption per day, but most of this water is wasted due to negligence and improper selection of faucets, showers, and appliances.

[0004] Related to the need to reduce water consumption is the need to reduce household energy consumption, especially considering that (at least in Europe) about 75% of heating and cooling is still generated from fossil fuels, while only 22% is generated from renewable energy sources.

[0005] According to Directive 2012 / 27 / EU, buildings account for 40% of the EU's final energy consumption and 36% of CO2 emissions. The European Commission's 2016 report, "Mapping and analyses of the current and future (2020-2030) heating / cooling fuel deployment (fossil / renewables)," concluded that heating and hot water alone account for 79% (192.5 Mtoe) of total final energy consumption in EU households. The Commission also reported that, "According to Eurostat data from 2019, approximately 75% of heating and cooling is still generated from fossil fuels, while only 22% is generated from renewable energy sources. To achieve the EU's climate and energy targets, the heating and cooling sector must significantly reduce energy consumption and the use of fossil fuels. Heat pumps (which extract energy from the air, ground, or water) have been identified as a potentially significant contributor to addressing this issue."

[0006] In many countries, there is policy pressure and pressure to reduce carbon footprints. For example, in the UK, the government published a white paper on future housing standards in 2020, proposing to reduce carbon emissions from new homes by 75% to 80% by 2025 compared to current levels. Furthermore, in early 2019, it was announced that gas boilers would be banned in new homes from 2025. It was reported that in the UK, 78% of the total energy used for building heating came from natural gas, while 12% came from electricity.

[0007] The UK has a large number of small properties with 2-3 bedrooms or fewer, with gas-fired central heating, and most of these properties use what are called duplex boilers, where the boiler acts as both an instant hot water heater and a boiler for central heating (space heating). Duplex boilers are popular because they combine a small form factor, provide a nearly direct “unlimited” source of hot water (20 to 35 kW output), and eliminate the need for hot water storage. Such boilers can be purchased relatively inexpensively from reputable manufacturers. The small form factor and the ability to operate without a hot water storage tank mean that such boilers can often be accommodated even in small apartments or houses (often wall-mounted in the kitchen), and a new boiler can be installed within a working day. Therefore, new duplex gas boilers can be installed inexpensively. With the impending ban on new gas boilers, alternative heat sources will be needed to replace gas-fired duplex boilers. Furthermore, previously installed duplex boilers will eventually need to be replaced with alternative boilers. Duplex boilers typically have dimensions ranging from approximately 70 cm to 200 cm in height, 420 cm to 150 cm in width, and 20 cm to 100 cm in depth. The average internal duplex boiler used in small to medium-sized homes is approximately 75 cm in height, 45 cm in width, and 50 cm in depth. However, these dimensions can vary depending on the manufacturer and the boiler's rated power.

[0008] With increasing concern about the environmental impact of energy consumption, there has been growing interest in using heat pump technology as a way to provide heated water for homes. A heat pump is a device that transfers heat energy from a heat source to a heat storage tank. Although heat pumps require electricity to perform the task of transferring heat energy from the heat source to the heat storage tank, they are generally more efficient than resistance heaters (electric heating elements) because they typically have a coefficient of performance (COP) of at least 3 or 4. This means that, for the same amount of electricity consumed, a heat pump can provide a user with 3 to 4 times more heat than a resistance heater.

[0009] The heat transfer medium that carries heat energy is called a refrigerant. Heat energy from the air (e.g., outside air, or air from a heated room in a house) or from a ground source (e.g., a ground loop or a well filled with water) is extracted by a receiving heat exchanger and transferred to the contained refrigerant. The refrigerant, now with higher energy, is compressed, thus significantly raising its temperature, and the now-hotter refrigerant exchanges heat energy with the heated water loop through a heat exchanger. In the context of supplying heated water, the heat extracted by the heat pump can be transferred to the water in an insulated tank that acts as a heat energy storage device, and the heated water can be used at a later time when needed. The heated water can be diverted to one or more water outlets as needed, such as faucets, showers, or radiators. However, compared to resistance heaters, heat pumps typically require more time to bring the water to the desired temperature.

[0010] While heat pumps have been proposed as a potential solution to the need to reduce dependence on fossil fuels and cut CO2 emissions, they are currently unsuitable for replacing gas boilers in smaller residential (and small commercial) properties due to several technical, commercial, and practical reasons. These properties are typically very large and require a sizable unit outside the property. Therefore, they cannot be easily retrofitted into a property with a typical duplex boiler. Units capable of providing an equivalent output to a typical gas boiler would currently be expensive and likely require significant electricity. These units themselves not only cost several times more than the equivalent gas equivalent, but their size and complexity mean that installation is technically complex and therefore expensive. Storage tanks for hot water are also required, which is another factor hindering the use of heat pumps in small residential homes. Another technical issue is that heat pumps tend to take a considerable amount of time to begin generating heat in response to demand, potentially requiring 30 seconds for self-testing, followed by some time to heat, resulting in a delay of one minute or more between requesting hot water and its delivery. For this reason, attempts to use renewable solutions with heat pumps and / or solar energy are typically suited to large properties with space for hot water storage tanks (with space requirements, heat loss, and Legionnaires' risk).

[0011] A significant portion of household energy consumption comes from the use of hot water, both in terms of the amount of hot water used and the energy waste caused by overheating. Of course, hot water waste is also a major cause of the more widespread problem of water waste, and this issue needs to be addressed if humanity is to have a sustainable future.

[0012] Whether in a commercial or residential setting, heated water is needed year-round. Needless to say, providing heated water requires both clean water and a heat source. To provide heated water, heating systems are typically supplied to centralized water supply systems to heat the water to a predetermined temperature, for example, set by the user, and the heat source is usually one or more electric heating elements or natural gas combustion. Typically, during periods of high energy demand (such as gas or electricity), utility providers implement peak-hour pricing, which increases the unit cost of energy, partly to cover the additional costs of purchasing more energy to supply customers, and partly to discourage unnecessary energy use. Then, during periods of low energy demand, utility providers implement off-peak pricing, which reduces the unit cost of energy to incentivize customers to switch energy use during these off-peak periods rather than peak periods, thus achieving a more balanced overall energy consumption over time. However, this strategy is only effective if customers are consistently aware of the price changes and, in addition, consciously strive to change their energy consumption habits.

[0013] Because different homes, workplaces, and commercial spaces have different requirements and preferences for heated water use, there is a need for new heated water supply methods that would allow heat pumps to become a viable alternative to electric heaters. Summary of the Invention

[0014] The present invention provides a hot water supply system as described in claim 1.

[0015] The present invention also provides a method for controlling a hot water supply system as described in claim 10.

[0016] The present invention further provides a corresponding computer program product as described in claim 15. Attached Figure Description

[0017] Embodiments of various aspects of this disclosure will now be described by way of example only with reference to the accompanying drawings, in which:

[0018] Figure 1 This is an illustrative system overview of an exemplary water supply system;

[0019] Figure 2 This is a schematic diagram showing a water supply facility within a building according to one aspect of this disclosure;

[0020] Figure 3 It is similar to Figure 2 A schematic diagram of a portion of the water supply system within a building, showing the components and flow paths;

[0021] Figure 4 It shows Figure 3The water supply facilities inside the building are illustrated in the first operating mode.

[0022] Figure 5 It shows Figure 3 The water supply facilities inside the building are illustrated in the second operating mode;

[0023] Figure 6 It shows Figure 3 The water supply facilities inside the building are illustrated in the third operating mode.

[0024] Figure 7 It shows Figure 3 The water supply facilities inside the building are illustrated in the fourth operating mode;

[0025] Figure 8 It shows Figure 3 The water supply facilities inside the building are illustrated in the fifth operating mode;

[0026] Figure 9 It shows Figure 3 The water supply facilities inside the building are illustrated in the sixth operating mode.

[0027] Figure 10 It shows Figure 3 The water supply facilities inside the building are illustrated in the seventh operating mode.

[0028] Figure 11 It shows Figure 3 The building's water supply facilities are illustrated in the eighth operating mode; and

[0029] Figure 12 It shows Figure 3 The diagram illustrates the building's water supply facilities, specifically the ninth operating mode. Detailed Implementation

[0030] When addressing household energy consumption, it is important to consider the energy used to provide hot water, which means considering not only the temperature of the water supplied or stored, but also the volume of hot water used. In many countries and regions considered to have ample fresh water, historically little attention has been paid to household water consumption, primarily reflected in the configuration of water supply systems and the flow rate at water outlets. It is not uncommon for bathtub faucets to have flow rates exceeding 15 liters per minute, kitchen faucets exceeding 12 liters per minute, and even basin faucets exceeding 10 liters per minute. Shower outlets can also have flow rates exceeding 15 liters per minute, with approximately two-thirds typically coming from the heat supply.

[0031] Over the past two decades, attitudes have changed as people have become more aware of water scarcity and as former public water providers have been privatized, leading to the introduction of household water meters and pay-as-you-go pricing. Consequently, new homes often have faucets and shower outlets with maximum flow rates that are about half to two-thirds of those in their historical counterparts. Nevertheless, not only are high-flow-rate faucets and showers still common in older homes, but even more modern outlets make it easy to use far more water than is strictly necessary for washing hands, bathing, or showering. Consider a shower with a flow rate of 15 liters per minute: a 12-minute shower would use 180 liters of water, of which about 100 to 110 liters would come from the heated supply. Hot water supply temperatures are typically in the range of 50 to 60 degrees Celsius – never heated by more than 10 degrees Celsius, and often heated from rather low temperatures. Therefore, it should be recognized that not only is a large amount of water used, but also a significant amount of energy is used to heat that water.

[0032] In addition, while high hot water supply temperatures of 50 to 60 degrees Celsius have the benefit of reducing the risk of Legionella infection, there is a considerable risk of burns in this temperature range.

[0033] In embodiments of this technology, cold water and heated water are supplied by a centralized water supply system to multiple water outlets in buildings used in residential or commercial environments, including faucets, showers, radiators, etc. Figure 1 An exemplary water supply system according to an embodiment is illustrated. In this illustrative system, water supply system 100 includes a control module 110, which may include one or more machine learning algorithms 120. Control module 110 is communicatively coupled to and configured to control various components of the water supply system, including a flow control 130, which may be, for example, in the form of one or more valves arranged to control the flow of water inside and outside the system; a (ground-source or air-source) heat pump 140 configured to extract heat from the surrounding environment and store the extracted heat in a thermal energy storage unit 150 for heating water; and one or more electric heating elements 160 configured to directly heat cold water to a desired temperature by controlling the amount of energy supplied to the electric heating elements 160. The heated water (whether heated by thermal energy storage unit 150 or by electric heating elements 160) is then directed to one or more water outlets as needed. In this embodiment, heat pump 140 extracts heat from the surrounding environment into a thermal energy storage medium within thermal energy storage unit 150. Furthermore, the thermal energy storage medium can be heated by other sources. The thermal energy storage medium is heated until it reaches the desired operating temperature, and then, for example, cold water from the main pipe can be heated to the desired temperature by the thermal energy storage medium. The heated water can then be supplied to the various water outlets in the system.

[0034] In this illustrative system, the control module 110 is configured to receive input from a plurality of sensors 170-1, 170-2, 170-3, ..., 170-n. These sensors 170-1, 170-2, 170-3, ..., 170-n may include, for example, one or more air temperature sensors, one or more water temperature sensors, one or more water pressure sensors, one or more timers, and one or more motion sensors located indoors and / or outdoors. They may also include other sensors not directly connected to the water supply system 100, such as a GPS signal receiver, a calendar, or a forecast application on a smartphone carried by a resident and communicating with the control module via a communication channel. In this embodiment, the control module 110 is configured to use the received input to perform various control functions, such as controlling the water flow rate to the thermal energy storage unit 150 or the electric heating element 160 via the flow control 130 to heat the water.

[0035] While heat pumps are generally more energy-efficient at heating water than resistance heaters, they require startup time as they perform various checks and cycles before reaching normal operating conditions and need time to transfer sufficient heat to the storage medium before reaching the desired operating temperature. Resistance heaters, on the other hand, typically provide heat more immediately. Therefore, a heat pump may take longer to heat the same amount of water to the same temperature compared to a resistance heater.

[0036] Figure 2A more detailed schematic diagram of a hot water supply facility 200 within a building is shown, which includes multiple controllable water outlets (various faucets and showers, described more fully later), a hot water supply source 205 with at least one outlet having a controllable outflow temperature, and at least one first temperature sensor 243 for detecting the outflow temperature, at least one flow measurement device 210, and at least one flow regulator 215 along the water flow path between the water supply source 205 and the multiple controllable water outlets. A processor 240 is operatively connected to at least one flow measurement device 210 and at least one flow regulator 215. The illustrated water supply facility represents a residence having a master bathroom 221, a first ensuite shower room 222, a second ensuite shower room 223, a cloakroom 224, and a kitchen 225. The master bathroom 221 and the first ensuite shower room 222 may be located on the first floor of the residence, while the cloakroom 224, the second ensuite 223, and the kitchen 225 may be located on another floor of the residence. In this scenario, as shown in the figure, it may be convenient to have two separate loops 230 and 231 to supply water to each outlet. Both loops 230 and 231 can be supplied with water from different outlets, the temperatures of which are individually adjustable, and each outlet 1 has its own associated temperature sensor 243. The temperature of the water at the outlet can be adjusted by mixing cold water with hot water from a fixed or variable temperature source, or by controlling the energy introduced into the heat source (such as an electric heating element or even a gas heater). Later, hot water systems will be described that include a thermal energy storage arrangement typically combined with a heat pump, and in such systems, the hot water supply temperature can typically be adjusted by mixing in different proportions of cold water from a cold water supply source. Sometimes, such systems may include an instantaneous heat source (such as an electric heating element) downstream of the thermal energy storage arrangement, controlled by the system's processor, and in such facilities, the control of the hot water supply temperature may involve controlling the amount of energy supplied to the instantaneous water heater, or it may be controlled by mixing in different proportions of cold water from a cold water supply source.

[0037] The main bathroom 221 is shown as including a shower outlet 235, a bathtub faucet or tap 236, and a sink tap 237. Ensuite shower rooms 222 and 223 also include a shower outlet 235 and a sink tap 237. Conversely, the walk-in closet 224 contains only a toilet (not shown) and a sink with a tap 238. Finally, the kitchen 235 has a sink with a tap 239.

[0038] A processor or system controller 240 with associated memory 241 is coupled to at least one flow measurement device 210 and at least one flow regulator 215. It should be understood that each of the two loops 230 and 231 is provided with a corresponding flow measurement device 210 and flow regulator 215. The processor may also optionally be connected to one or more temperature sensors 243, one temperature sensor for each of loops 230 and 231. The processor may be associated with an energy reservoir.

[0039] The processor may also be coupled to an RF transceiver 242, which includes at least one RF transmitter and at least one RF receiver for bidirectional communication via Wi-Fi, Bluetooth, etc., and preferably also coupled to the Internet 244 for connection to a server or central station 245, and optionally coupled to a cellular radio network (e.g., LTE, UMTS, 4G, 5G, etc.). Through the RF transceiver 242 and / or the Internet connection, the processor 240 is able to communicate with a mobile device 250, which may be, for example, a smartphone or tablet, for installation engineers to configure (and optionally map) water supply facilities within a building. The mobile device 250 includes software (e.g., a specific application) that collaborates with corresponding software in the system controller 240 and potentially in the server 245 to facilitate configuration (and optionally mapping) methods according to embodiments of the invention, and particularly to synchronize actions taken by the engineer with the clock of the system controller 240 / server 245. The memory 241 contains code that enables the processor to perform methods for configuring (and optionally mapping) the water supply facility processor within the building, for example, during the commissioning of a new facility.

[0040] During commissioning, to configure the hot water supply facility 200, engineers can be instructed to install temperature sensors directly below specific hot water outlets (e.g., specific faucets or shower outlets) and fully open the outlets at specific times. The system processor is configured to measure the flow rate, the difference between the outflow temperature and the supplied temperature, the time delay, and preferably the outdoor temperature (data provided from an external temperature sensor). This allows algorithms (e.g., MLA) to calculate, by allocating system heat losses, the distance between the outlet (faucet or shower outlet) and the hot water source, and ultimately accurately adjust the outflow temperature to achieve the correct water temperature at the relevant controllable outlet (e.g., the faucet). For example, if the household includes children, the maximum hot water temperature for each outlet, except for, for example, the kitchen sink, can be limited to 40°C or 41°C, while if there is an infant in the household, the maximum temperature can be limited to 37°C. Even in the absence of children, the maximum temperature for all outlets except the kitchen sink can be set to 43°C, while the maximum temperature for the shower outlet might be set to 41°C.

[0041] The system can also be configured to restrict hot water flow to certain categories of water outlets (such as washbasins and sinks, and possibly showers), with different maximum flow rates set for each category of outlet, and / or a specific maximum flow rate can be set for a particular outlet—thus, for example, a lower flow rate for bathrooms and dressing rooms used by children. The determination of maximum temperature and flow rate can be based on rules provided by the system supplier. We will discuss later hot water supply systems using heat pumps and thermal storage arrangements, and such systems significantly benefit from the application of temperature and flow rate control—since heat pumps sized according to the space heating needs of a modestly sized 1- to 3-bedroom home typically do not have the heating capacity to meet the immediate hot water needs of a household without a large-capacity hot water storage tank. By managing hot water flow and temperature, the need for providing hot water storage can be eliminated, while minimizing the scale of energy shortages that would otherwise need to be addressed by other means. If the facility does include a thermal storage arrangement and a heat pump, the system supplier will typically pre-program the processor with appropriate temperature and flow values ​​based on the outlet type and household composition.

[0042] A database of temperatures and optional flow rates, based on outlet type and household composition, is also available to the system controller via the Internet and is updated from time to time. The user interface for the system controller provides residents and / or service engineers with the means to adjust various settings according to changes in household composition – and also to allow users to set lower maximum temperatures and / or flow rates, for example, when guests arrive with infants, children, or elderly or infirm persons.

[0043] Figure 3 The heating system 300 is schematically shown, illustrating its compatibility with the above reference. Figure 1 The described system includes some components used in similar systems and the flow paths between these components. As shown, heating system 300 includes a main cold water inlet 302 and a domestic hot water outlet 304 (e.g., a faucet or shower outlet) and a domestic hot water heating appliance 310 (e.g., a radiator). System 300 further includes a heat pump 306, typically with a heating capacity of 3-12 kW, a heat exchanger 308, and a heat storage appliance 342, such as a relatively small tank holding approximately 15 liters of water. These components are connected via water flow pipes, through which flow transducers, temperature transducers, and valves control the flow rate of water, as described below. Both flow transducers and temperature transducers are connected via signal lines to provide signals to a system controller 340, which controls the valves to control the system to operate in one of several operating modes, as described below. One, some, or all of the flow transducers may be replaced by pressure transducers, which determine the pressure of the fluid to determine the flow rate.

[0044] Starting from the main cold water inlet 302, a first flow path 312 leads to the first inlet HX1 of the heat exchanger 308. Temperature transducer TT01 and flow transducer FT01 measure the temperature and flow rate of the cold water at the main cold water inlet 302. Temperature transducer TT02 and flow transducer FT03 measure the temperature and flow rate at the first inlet HX1 of the heat exchanger 308. A second flow path 314, near the main cold water inlet 302, leads from the first flow path 312 to the domestic hot water outlet 304. A first electric valve MV01 is located on the second flow path 314 to regulate the water flow rate within it. Flow transducer FT02 measures the flow rate of the cold water passing through the first electric valve MV01 toward the domestic hot water outlet 304, where the cold water is selectively combined with water flowing out of the electric three-way valve MV03, which will be further described below. Temperature transducer TT07, adjacent to the domestic hot water outlet, measures the temperature of the water leading to the domestic hot water outlet 304.

[0045] The first portion 316a of the third flow path 316 extends from the first flow path 312 to a location closer to the heat exchanger 308 compared to the second flow path 314. A second electric valve MV02 is located on the first portion 316a of the third flow path 316 to regulate the water flow rate within the first portion 316a of the third flow path 316 leading to the lower portion of the heat storage device 342. A temperature transducer TT11 measures the water temperature at the lower portion of the heat storage device 342, and another temperature transducer TT10 measures the water temperature at the upper portion of the heat storage device 342. The second portion 316b of the third flow path 316 extends from the upper portion of the heat storage device 342 to the second inlet B of the electric three-way valve MV03, wherein a temperature transducer TT05 measures the water temperature in the second portion 316b of the third flow path 316. A return path 318 is provided to allow water to return from the outlet of the electric valve MV02 on the first part 316a of the third flow path 316 to the inlet of the electric valve MV02 via the circulation pump 320 and the check valve 322.

[0046] Heat exchanger 308 has a first outlet HX2 connected to receive water entering the heat exchanger through a first inlet HX1. A fourth flow path 324 extends from the first outlet HX2 of the heat exchanger to the first inlet A of an electric three-way valve MV03 via an electric heater 326. Temperature transducer TT03 measures the temperature of the water flowing out of the first outlet HX2 of the heat exchanger 308, and temperature transducer TT04 measures the temperature of the water flowing out of the electric heater 326 and into the first inlet A of the electric three-way valve MV03. A fifth flow path 328 extends from the outlet AB of the electric three-way valve MV03 to the domestic hot water outlet 304, and combines with the first flow path 314 before reaching the domestic hot water outlet 304. Temperature transducer TT06 measures the temperature of the water flowing out of the outlet AB of the electric three-way valve MV03 before combining with the water from the second flow path 314, and temperature transducer TT07 measures the temperature of the water after combining with the water from the second flow path 314 as it enters the domestic hot water outlet 304.

[0047] Looking from the first inlet HX1 and the first outlet HX2, on the other side of heat exchanger 308 are the second inlet HX3 and the second outlet HX4. The second inlet HX3 is fed water via a sixth flow path 330, leading from the outlet of heat pump 306 through an electrically operated three-way valve MV04, where a temperature transducer TT08 measures the temperature of the water at the second inlet HX3 of heat exchanger 308. A seventh flow path 332 is coupled between the second outlet HX4 of heat exchanger 308 and the inlet of heat pump 306. As shown, heat pump 306 includes a heat exchanger 334 and a circulation pump 336 to heat the water received at the inlet and output heated water. A temperature transducer TT09 measures the temperature of the water flowing out of heat exchanger 308 and into the inlet of heat pump 306. Therefore, the electrically operated three-way valve MV04 has a first inlet A coupled to the outlet of heat pump 306 and an outlet AB coupled to the second inlet HX3 of heat exchanger 308. The second outlet B of the electric three-way valve MV04 is connected to the inlet of the domestic hot water heater 310, and the outlet of the domestic hot water heater is connected to the seventh flow path 332.

[0048] The dashed line marked 344 illustrates all the components of the system that may be included in the housing, which may be manufactured to have a similar size and shape to replace the duplex boiler. However, those skilled in the art will recognize that in some cases, these components may be arranged otherwise inside or outside such housing, which may not be necessary in some cases. In particular, for example, the temperature transducer TT09 may be located inside housing 344, closer to heat exchanger 308, or outside housing 344, closer to domestic hot water heating appliance 310. Other temperature and flow transducers (e.g., flow transducer FT01 and / or temperature transducer TT01) may similarly be positioned inside or outside the housing as needed.

[0049] Now refer to Figures 4 to 12 These figures provide a more comprehensive description of the operating modes of the heating system 300. Figure 3 The system is described, but for clarity, there are no signal lines or devices between the controller 340 and the various flow transducers and temperature transducers. Instead, the flow paths used in a particular operating mode are shown with superimposed dashed lines to illustrate which flow paths and components are being controlled in that mode. Several different operating modes exist, each of which will be described in turn, but several operating modes may be related to each other and used in combination or individually. These modes include:

[0050] Mode 1 ( Figure 4 ): Heat exchanger charging mode, in which heat exchanger 308 is used to heat the water used to fill (or charge) the heat storage appliance 342;

[0051] Mode 2 ( Figure 5 ): Electric heater charging mode, in which electric heater 326 is used to heat the water used to charge the thermal storage appliance 342;

[0052] Mode 3 ( Figure 6 ): Initial hot water mode, in which hot water supplied to the domestic hot water outlet 304 is provided by the thermal energy storage appliance 342 (if it is filled with hot water), or by the electric heater 326, or by a combination of both as needed;

[0053] Mode 4 ( Figure 7 ): Mixing mode, used to mix water from mode 3 with cold water from the main cold water inlet 302 to lower its temperature, thereby lowering the temperature of the water supplied to the domestic hot water outlet 304;

[0054] Mode 5 ( Figure 8): Steady-state mode, in which heat pump 306 heats water from cold water inlet 302 at heat exchanger and provides heated water, which may optionally be further heated by electric heater 326 and mixed with cold water from cold water inlet 302 to reduce the temperature of water supplied to domestic hot water outlet 304.

[0055] Mode 6 ( Figure 9 ): Combination pattern, which is a combination of pattern 3 and 5;

[0056] Mode 7 ( Figure 10 Heat pump defrosting mode;

[0057] Mode 8 ( Figure 11 ): Housing heating modes; and

[0058] Mode 9 ( Figure 12 ): The overall mode, which is a combination of modes 6 and 8.

[0059] First go to Figure 4 The diagram illustrates a first operating mode (“heat pump charging in storage mode”), in which hot water supplied from heat exchanger 308 is charged into storage appliance 342. In this first operating mode, the second electric valve MV02 is closed and the circulation pump 320 on the return path 318 is opened, allowing water to be pumped from storage appliance 342 to the first inlet HX1 of heat exchanger 308 via circulation pump 320, check valve 322, and first flow path 312. Water from domestic cold water inlet 302 does not affect the flow rate because water is pumped from the first portion 316a of the third flow path 316 into the first flow path 312. The water is heated in heat exchanger 308 and flows from the first outlet HX2 through the fourth flow path 324 via electric heater 326 (which is closed in this mode) to electric valve MV03, which is controlled to direct water from port A to port B, thus returning water to storage appliance 342. It will be apparent that, if desired, the water can circulate in this manner more than once until the water at the heat storage unit 342 reaches a predetermined temperature as measured by temperature transducer TT10 or temperature transducer TT04. To supply hot water from the heat pump to heat exchanger 308, the electric valve MV04 is controlled such that water in the sixth flow path 330, originating from heat pump 306, passes through port A to port AB of electric valve MV04, and thus reaches the second inlet HX3 of heat exchanger 308. The water then returns to heat pump 306 from the second outlet HX4 of heat exchanger 308.

[0060] In this first mode, the heat pump power is adjusted to transfer heat to the circulating hot water loop, thereby charging the thermal energy storage device 342 (e.g., a 15-liter tank), while the circulation pump 320 continues to operate on the hot water side. An example scenario would be that if the circulation pump 320 operates at 6 L / min, and the heat pump 306 is adjusted to heat the water in the hot water loop to 55°C at the heat exchanger 308, the circulation pump 320 will run for approximately 6 minutes, charging the thermal energy storage device 342 twice through the loop to reach 55°C.

[0061] Figure 5 The illustration shows a second operating mode (“Electric Heater Charging in Thermal Storage Mode”), in which thermal storage appliance 342 is charged with hot water heated by electric heater 326. In this mode, similar to the first mode, the second electric valve MV02 is closed and the circulation pump 320 on the return path 318 is opened, allowing water to be pumped from the thermal storage appliance to the first inlet HX1 of the heat exchanger 308 via the circulation pump 320, check valve 322, and first flow path 312. In this mode, the heat pump does not supply heat to the heat exchanger, so water is transferred from the first outlet HX2 of the heat exchanger to the electric heater 326 via the fourth flow path 324, where the electric heater is effectively controlled to heat the water. The hot water is then passed to the electric valve MV03, which is controlled to direct water from port A to port B, thus returning the hot water to the thermal storage appliance 342. It will be obvious that, if desired, the water can be circulated more than once until the water at the thermal storage device 342 reaches the predetermined temperature as measured by temperature transducer TT10 or temperature transducer TT04.

[0062] In this second mode, the power of the electric heater is adjusted to heat the circulating water on the hot water side to the desired temperature. For example, if the circulation pump 320 is running at 5 L / min and the electric heater 326 is adjusted to heat the water in the hot water loop to 55°C as measured at the temperature transducer TT04, the circulation pump 320 will run for 6 minutes to fill the thermal energy storage device 342 twice to reach 55°C.

[0063] Therefore, the controller can choose to use either the first mode or the second mode to charge the thermal energy storage appliance. This can depend on whether the heat pump is available and operational. If the heat exchanger is operational and the hot fluid is already available at the heat exchanger, the first mode can be selected. If the heat pump is operational, but the electric valve MV04 does not allow the hot fluid to be fully transferred to the heat exchanger, the first mode can still be selected, and the electric valve MV04 can be controlled as described above, so that the hot fluid is transferred from port A to port AB and thus to the second inlet HX3 of the heat exchanger. On the other hand, if the heat pump is not operational, and given that it takes some time for the heat pump to start generating hot fluid, as described above, the controller can select the second mode to heat the water using an electric heater to charge the thermal energy storage appliance.

[0064] exist Figure 6In the third operating mode (“Initial Hot Water Mode”) shown, hot water is supplied to the domestic hot water outlet 304 either by the thermal energy storage unit 342 (if it is filled with hot water), or by the electric heater 326, or a combination of both. If the thermal energy storage unit 342 is full of hot water, the hot water can be used, prioritizing the use of the electric heater 326 to heat the water. To use the hot water from the thermal energy storage unit 342, the electric valve MV02 is opened, allowing the third flow path 316 to draw cold water from the main cold water inlet 302 to displace the hot water from the thermal energy storage unit 342. The hot water from the thermal energy storage unit 342 passes through the electric valve MV03 from port B to port AB. As the temperature of the water from the thermal energy storage unit 342 decreases (due to mixing with the cold water from the main cold water inlet 302), the electric valve MV03 is controlled to gradually open the passage from port A to port AB while gradually closing the passage from port B to port AB. The flow velocities at ports A-AB and B-AB are configured to be inversely proportional, keeping the water flow rate from port AB into the fifth flow path 328 leading to the domestic hot water outlet 304 constant. This is adjusted based on the temperature sensed at the temperature transducer TT06, depending on whether the sensed temperature is lower than the desired temperature at the temperature transducer TT06. Therefore, if the temperature at the temperature transducer TT06 is lower than the desired temperature, the proportion of fluid allowed to flow to port B of port AB can be reduced from 100% to allow flow through port A, while reducing the flow rate from port B. The reduced flow rate from port B is now mixed with the flow rate from port A. Water passing through port A via the electric valve MV03 comes from the fourth flow path 324 and passes through the electric heater 326, where the water is heated as needed to provide hot water at port AB at the desired temperature sensed by the temperature transducer TT06. Water in the fourth flow path 324 comes from the heat exchanger 308, having already reached the heat exchanger via the first flow path 312 starting from the main cold water inlet 302. This operating mode depends on the thermal energy storage device 342 being pre-charged, for example, via either the first or second operating mode.

[0065] Typically, water in the thermal energy storage device 342 is filled to 1.25 times the desired temperature sensed at temperature transducer TT07, measured as the temperature at temperature transducers TT11 and TT10. When there is a secondary hot water flow demand, as measured at flow transducer FT01, water flows through a third flow path 316 and into the thermal energy storage device 342. The thermal energy storage device 342 may be a 15 L tiered tank, wherein the 15 L of water entering at the temperature measured by temperature transducer TT01 will displace 15 L of preheated hot water. Tank depletion is measured by reading the temperatures at temperature transducers TT10 and TT11 and by knowing the amount of water that has passed through the tank.

[0066] V = t*(Q@FT01-Q@FT03-Q@FT02)

[0067] In the formula, V represents the depletion of the can;

[0068] t is time;

[0069] Q@FT01 is the flow rate measured at the flow transducer FT01;

[0070] Q@FT02 is the flow rate measured at the flow transducer FT02; and

[0071] Q@FT03 is the flow rate measured at the flow transducer FT03.

[0072] When water flows out of the tank and into port B of the electric valve MV03, if for any reason the temperature at temperature transducer TT05 is lower than the desired temperature at temperature transducer TT07, the electric heater 326 can be used to raise the temperature of the water passing through the fourth flow path 324, wherein the electric valve MV03 is controlled to at least partially open port A to allow at least a certain proportion of the flow rate measured at flow transducer FT01 to reach the electric heater 326 through the fourth flow path 324, wherein the bypass proportion of the flow rate at flow transducer FT03 can be controlled by the electric heater 326 to heat from the temperature at temperature transducer TT03 to the temperature at temperature transducer TT04.

[0073] This is a useful mode for use when the heat pump 306 is not operating or not yet fully operational, in which case the heat pump does not supply hot fluid to the heat exchanger 308. Of course, as the heat pump heats up, the fluid will begin to become hotter and can be supplied to the heat exchanger 308, allowing the water passing through the heat exchanger to begin to rise in temperature, as measured by the temperature transducer TT03, so that the heating provided by the electric heater 326 can be controlled to produce the appropriate desired temperature.

[0074] Figure 7A fourth operating mode is shown, which is a mixing mode, in which the temperature of hot water from the thermal energy storage appliance 342 and / or from the electric heater 326 (provided according to the third operating mode described above) or from the heat exchanger 308 (if the heat exchanger produces hot water according to the fifth mode) is mixed with cold water from the main cold water inlet 302 to reduce the temperature of the water supplied to the domestic hot water outlet 304. In this mode, the temperature of the hot water flowing out of port AB of the electric three-way valve MV03 is measured using a temperature transducer TT06, regardless of whether the hot water flowing out of port AB of the electric three-way valve MV03 is provided via the heat exchanger 308 through the fourth flow path 324 (regardless of whether the water is heated by the electric heater 326) or from the thermal energy storage appliance 342. The temperature is signaled to the system controller 340. Figures 4 to 12 (Not shown in the diagram). Then, the controller 340 determines whether the temperature at the temperature transducer TT06 is higher than the desired temperature of the hot water available at the domestic hot water outlet 304. If the temperature is higher, the controller opens the electric valve MV01 to mix the cold water from the second flow path 314 into the hot water flowing out of port AB of the electric three-way valve MV03 into the fifth flow path 328, so as to allow the cold water from the main cold water inlet 302 to flow through the second flow path 314 to the fifth flow path 328. The amount by which the electric valve MV01 opens will depend on the temperature of the cold water from the main inlet 302, as measured by the temperature transducer TT01, and the flow rate of the cold water from the main inlet 302, as measured by the flow transducer FT01, to produce the desired flow rate, as measured by the flow transducer FT02 on the second flow path 314 leading to the fifth flow path 328. This allows the cold water from the second flow path 314 to mix with the hot water in the fifth flow path 328 to produce the desired temperature of the water available at the domestic hot water outlet 304, as measured by the temperature transducer TT07. A suitable control program executed by the controller will regulate this mixing during normal operation, thereby preventing any overshoot at the domestic hot water outlet 304 relative to the desired temperature.

[0075] This serves primarily as a safety feature to prevent scalding for users who do not have temperature safety valves installed on their faucets or taps in their homes. Secondly, the mixing allows the thermal storage appliance 342 to be charged to a temperature higher than the desired outlet temperature, so that when the system operates in the mode where the thermal storage appliance 342 provides hot water to be used from the domestic hot water outlet 304, the higher-temperature water mixes with the cold water from the main cold water inlet, thereby producing a slower discharge at the thermal storage appliance 342 and giving the thermal storage appliance a proportionally higher effective volume.

[0076] After the third operating mode, where hot water is initially supplied by the thermal energy storage device 342 or from the electric heater 326 (or a combination of both), a fifth operating mode can be established once the heat pump has reached full operation and is supplying hot fluid to the heat exchanger 308. In this steady-state mode, such as Figure 8 As illustrated, the electric valve MV02 is closed, preventing flow through the third flow path 316 and the thermal energy storage device 342. The electric heater 326 is active and controllable by the controller. The mixing control described above with reference to the fourth mode is also active. Therefore, the electric valve MV04 is controlled to transfer water from port A to port AB. In this mode, the heat pump 306 efficiently supplies heated fluid through the sixth flow path 330, and the electric valve MV04 is set to transfer the fluid at a temperature determined by the flow rate of the measured secondary hot water demand from port A to port AB to reach the heat exchanger 308, and to set the hot water temperature as measured by the temperature transducer TT07. The water flow through the heat exchanger 308 is heated by the heat exchanger to the temperature measured by the temperature transducer TT03. Therefore, the flow rate measured at the flow transducer FT03, the temperature measured by the temperature transducer TT02, and the temperature measured by the temperature transducer TT03 can be used to determine the amount of energy supplied by the heat pump and subsequently provide feedback to the heat pump for power output adjustment. If the temperature measured by temperature transducer TT03 is determined to be lower than the desired temperature at temperature transducer TT07, then the electric heater 326 is controlled to heat the water to raise its temperature to the desired temperature as measured at temperature transducer TT04. It will be apparent that, since water travels from port A through the electric valve MV03 to port AB, the temperature measured by temperature transducer TT04 will be the same as the temperature at temperature transducer TT06. If the temperature measured by temperature transducer TT06 is higher than the desired temperature at temperature transducer TT07, cold water can be mixed with hot water as described for a fourth operating mode, in which the temperature of the hot water is mixed with cold water from the main cold water inlet 302 to lower the temperature of the water supplied to the domestic hot water outlet 304.

[0077] Figure 9 A sixth operating mode is shown, which is essentially a combination of the third (initial hot water) mode and the fifth (steady-state) mode. Hot water is supplied from heat exchanger 308 or from heat storage device 342. If the water temperature measured at temperature transducer TT06 is lower than the desired water temperature at temperature transducer TT07, electric heater 326 can be used to raise the water temperature from heat exchanger 308. On the other hand, if the water temperature measured at temperature transducer TT06 is higher than the desired water temperature at temperature transducer TT07, cold water from main cold water inlet 302 via second flow path 314 can be mixed with the hot water to lower its temperature to the desired temperature.

[0078] Sometimes, in severe weather, heat pumps are at risk of freezing. In such cases, whether defrosting a frozen heat pump or attempting to prevent it from freezing when the temperature is known to drop below freezing, the controller can control the system to enter a seventh operating mode (“Heat Pump Defrosting Mode”). In this seventh operating mode, such as Figure 10 As shown, the second electric valve MV02 is closed and the circulation pump 320 on the return path 318 is opened, allowing water to be pumped from the thermal storage unit 342 to the first inlet HX1 of the heat exchanger 308 via the circulation pump 320, check valve 322, and first flow path 312. Water from the domestic cold water inlet 302 does not affect the flow rate because water is pumped from the first portion 316a of the third flow path 316 into the first flow path 312. Water from the first outlet HX2 passes through the electric heater 326 and through the fourth flow path 324 to the electric valve MV03, which is controlled to direct water from port A to port B, allowing the water to return to the thermal storage unit 342 and be recirculated. The water entering at the first inlet HX1 of the heat exchanger 308 is controlled to be hot, either from the thermal storage unit, or more likely from the electric heater 326, or a combination of both, depending on the degree to which the thermal storage medium is charged with hot water.

[0079] In this seventh mode, the electric heater is active and regulated to transfer heat to the circulating hot water loop, passing through the thermal energy storage device 342. The electric valve MV04 is controlled so that water in the sixth flow path 330, starting from the heat pump 306, passes through port A to port AB of the electric valve MV04, and thus reaches the second inlet HX3 of the heat exchanger 308. The water then returns to the heat pump 306 from the second outlet HX4 of the heat exchanger 308. As the water flows from the second inlet HX3 to the second outlet HX4 of the heat exchanger 308, it is heated, as described above, by exchanging heat with the hot water that enters the first outlet HX1 of the heat exchanger 308 through the first inlet HX1. The heated water returning to the heat pump 306 can then provide heat to the refrigerant loop at the heat pump 306, which in turn circulates through the heat pump's compressor. The now-hot refrigerant can then defrost the evaporator coils.

[0080] Figure 11 The eighth mode (“House Heating Mode”) illustrated herein assumes that no hot water is needed at the domestic hot water outlet 304 (or any other hot water outlet), and this mode therefore focuses solely on providing a heat fluid, which may be water, for heating a home or other building using radiators or a hot water underfloor heating system. In this mode, the heat pump effectively produces hot water, which is directed through an electric valve MV04 controlled to transfer the hot water from port A to port B, such that the hot water is delivered to the domestic hot water heating appliance 310, whose outlet returns to the heat pump 306.

[0081] Figure 12 The diagram illustrates a ninth mode, which is a combination of modes six and eight. Therefore, this ninth mode is a combination of mode three (initial hot water), mode five (steady-state), and mode eight (house heating), allowing for the combination of all the various modes discussed above as needed. In this mode, electric heater 326 is active and adjustable, and all four electric valves MV01, MV02, MV03, and MV04 are active and adjustable. In this mode, heat pump 306 can simultaneously provide heating (according to mode eight discussed above) and thermal energy to heat or preheat the hot water at heat exchanger 308. As described above regarding mode six, hot water is supplied from heat exchanger 308 or from storage appliance 342. If the water temperature measured at temperature transducer TT06 is lower than the desired water temperature at temperature transducer TT07, electric heater 326 can be used to raise the water temperature from heat exchanger 308. On the other hand, if the water temperature measured at temperature transducer TT06 is higher than the desired water temperature at temperature transducer TT07, then cold water from the main cold water inlet 302 through the second flow path 314 can be mixed into the hot water to lower its temperature to the desired temperature.

[0082] As described above, most components of the system (excluding the heat pump 306, the domestic hot water outlet 304, and the domestic hot water heating appliance 310) are typically housed within an outer casing (or housing) 344, which may be manufactured to have a similar size and shape to replace the duplex boiler. The housing 344 may include insulation material to reduce heat loss, and it will be apparent that different operating modes may be used in combination or individually as needed and controlled by a controller.

Claims

1. A household hot water supply system, comprising: A cold water inlet, which is used to receive cold water from the main supply source; A hot water outlet, the hot water outlet being connected to provide hot water as needed to a household hot water outlet activated by a user; A heat exchanger having a water inlet connected to the cold water inlet and a water outlet, the heat exchanger selectively heating the water between the water inlet and the water outlet using a hot fluid selectively received from a hot fluid source; An electric heater for selectively heating water; A heat storage device for storing heat, the heat storage device being connected to the hot water outlet; A circulation pump for pumping water from the thermal storage device to the heat exchanger; A first flow path, the first flow path being between the cold water inlet and the water inlet of the heat exchanger; A second flow path, which is between the cold water inlet and the fifth flow path; A third flow path, the third flow path being between the thermal storage device and the fifth flow path; The fourth flow path is between the water outlet of the heat exchanger and the fifth flow path; The fifth flow path extends from the fourth flow path and the third flow path to the hot water outlet; as well as A controller, coupled to the heat exchanger, the electric heater, the thermal storage device, and the circulating pump, is used to control the operation of the hot water supply system in one or more operating modes, the one or more operating modes including: A heat exchanger charging mode, wherein the heat exchanger charging mode is used to charge the heat storage appliance with hot water heated by the heat exchanger, the heat exchanger charging mode includes: a) Determine whether hot water is needed at the household hot water outlet, and if it is determined that hot water is not needed at the household hot water outlet, then: b) Control the system to pump water from the thermal storage device through the circulation pump to the water inlet of the heat exchanger via the first flow path. c) Heating the water in the heat exchanger, the heat exchanger being arranged to provide a first higher level of heating. d) Control the system to pump the heated water from the heat exchanger through the fourth flow path and the electric heater to return it to the thermal storage unit through the third flow path, wherein the electric heater is controlled to be inactive. e) Determine the temperature of the water input into the thermal storage appliance. f) Determine whether the temperature has reached the predetermined temperature, and g) If the temperature has not yet reached the predetermined temperature, repeat steps b)-f). An electric heater charging mode, wherein the electric heater charging mode is used to charge the thermal storage appliance with hot water heated by the electric heater, the electric heater charging mode includes: h) Determine whether hot water is needed at the household hot water outlet, and if it is determined that hot water is not needed at the household hot water outlet, then: i) The system controls the pumping of water from the thermal storage unit via the circulation pump into the first flow path to the heat exchanger, through the heat exchanger, and from the heat exchanger through the fourth flow path to the electric heater, the heat exchanger being arranged to provide a second, lower level of heating or not to provide heating. j) The water is heated using the electric heater. k) Control the system to deliver the heated water back to the thermal storage appliance via the third flow path. l) Determine the temperature of the water input into the thermal storage device. m) Determine whether the temperature has reached the predetermined temperature, and n) If the temperature has not yet reached the predetermined temperature, repeat steps i)-m). The controller selects either the heat exchanger charging operation mode or the electric heater charging operation mode based on the availability of the heat fluid to be supplied to the heat exchanger from the heat fluid source.

2. The domestic hot water supply system according to claim 1, wherein, When it is determined in step a) or h) that hot water is needed at the domestic hot water outlet: Determine whether the heat exchanger is receiving heat fluid from the heat fluid source, and when it is determined that the heat exchanger is not receiving heat fluid from the heat fluid source, control the operation of the hot water supply system to an initial hot water mode, which is used to supply hot water to the hot water outlet, the initial hot water mode including: o) Determine whether the heat storage medium contains sufficient heat to provide the required hot water; p) If the heat storage device stores sufficient heat, the system is controlled to transfer hot water from the heat storage device through the third flow path to the fifth flow path leading to the hot water outlet. q) If the heat storage device does not store sufficient heat, the system is controlled to transfer water from the heat exchanger through the fourth flow path, through the electric heater, to the fifth flow path, the electric heater being controlled to heat the water flowing through it; and r) Repeat steps o)–q) whenever it is determined that hot water is needed at the domestic hot water outlet and the heat exchanger is not receiving hot fluid from the heat fluid source.

3. The hot water supply system according to claim 1 or claim 2, the hot water supply system further comprising one or more temperature sensors located in or adjacent to the heat storage medium and coupled to transmit a temperature signal to the controller, thereby enabling the controller to determine the temperature of the water input to the heat storage appliance in steps e) and l) and / or to determine in step o) whether sufficient heat is stored in the heat storage medium.

4. The hot water supply system according to any one of claims 1 to 3, the hot water supply system further comprising one or more flow transducers located on or adjacent to a flow path leading to the hot water outlet, the one or more flow transducers being coupled to transmit a flow signal to the controller, thereby enabling the controller to determine whether hot water is needed at the domestic hot water outlet.

5. The hot water supply system according to any one of claims 1 to 3, the hot water supply system further comprising one or more pressure transducers located on or adjacent to a flow path leading to the hot water outlet, the one or more pressure transducers being coupled to transmit a pressure signal to the controller, thereby enabling the controller to determine whether hot water is needed at the domestic hot water outlet.

6. The hot water supply system according to any of the preceding claims, wherein, The cold water inlet, the hot water outlet, the controller, the heat exchanger, the electric heater, the heat storage device, and the circulation pump are contained within the housing.

7. The hot water supply system according to claim 6, wherein, The footprint of the casing is similar to that of a household duplex boiler.

8. The hot water supply system according to claim 6, wherein, The maximum dimensions of the shell are 90 cm high, 60 cm wide and 60 cm deep.

9. The hot water supply system according to claim 8, wherein, The dimensions of the shell are approximately 75 cm high, approximately 45 cm wide, and approximately 50 cm deep.

10. A method for controlling a domestic hot water supply system, the domestic hot water supply system comprising: A cold water inlet, which is used to receive cold water from the main supply source; A hot water outlet, which is used to provide hot water as needed to a household hot water outlet activated by a user and connected to the cold water inlet; A heat exchanger having a water inlet connected to the cold water inlet and a water outlet connected to the hot water outlet, the heat exchanger selectively heating the water between the water inlet and the water outlet using a hot fluid selectively received from a heat fluid source; An electric heater for selectively heating water; A heat storage device for storing heat, the heat storage device being connected to the hot water outlet; A circulation pump for pumping water from the thermal storage device to the heat exchanger; A first flow path, the first flow path being between the cold water inlet and the water inlet of the heat exchanger; A second flow path, which is between the cold water inlet and the fifth flow path; A third flow path, the third flow path being between the thermal storage device and the fifth flow path; The fourth flow path is between the water outlet of the heat exchanger and the fifth flow path; The fifth flow path extends from the fourth flow path and the third flow path to the hot water outlet; as well as A controller coupled to the heat exchanger, the electric heater, the thermal storage device, and the circulating pump; The method includes the controller controlling the operation of the hot water supply system in one or more operating modes, the one or more operating modes including: A heat exchanger charging mode, wherein the heat exchanger charging mode is used to charge the heat storage appliance with hot water heated by the heat exchanger, the heat exchanger charging mode includes: a) Determine whether hot water is needed at the household hot water outlet, and if it is determined that hot water is not needed at the household hot water outlet, then: b) Control the system to pump water from the thermal storage device through the circulation pump to the water inlet of the heat exchanger via the first flow path. c) Heating the water in the heat exchanger, the heat exchanger being arranged to provide a first higher level of heating. d) Control the system to pump the heated water from the heat exchanger through the fourth flow path and the electric heater to return it to the thermal storage unit through the third flow path, wherein the electric heater is controlled to be inactive. e) Determine the temperature of the water input into the thermal storage appliance. f) Determine whether the temperature has reached the predetermined temperature, and g) If the temperature has not yet reached the predetermined temperature, repeat steps b)-f). An electric heater charging mode, wherein the electric heater charging mode is used to charge the thermal storage appliance with hot water heated by the electric heater, the electric heater charging mode includes: h) Determine whether hot water is needed at the household hot water outlet, and if it is determined that hot water is not needed at the household hot water outlet, then: i) The system controls the pumping of water from the thermal storage unit via the circulation pump into the first flow path to the heat exchanger, through the heat exchanger, and from the heat exchanger through the fourth flow path to the electric heater, the heat exchanger being arranged to provide a second, lower level of heating or not to provide heating. j) The water is heated using the electric heater. k) Control the system to deliver the heated water back to the thermal storage appliance via the third flow path. l) Determine the temperature of the water input into the thermal storage device. m) Determine whether the temperature has reached the predetermined temperature, and n) If the temperature has not yet reached the predetermined temperature, repeat steps i)-m). The controller selects either the heat exchanger charging operation mode or the electric heater charging operation mode based on the availability of the heat fluid to be supplied to the heat exchanger from the heat fluid source.

11. The method for controlling a domestic hot water supply system according to claim 10, wherein, When it is determined in step a) or h) that hot water is needed at the domestic hot water outlet: Determine whether the heat exchanger is receiving heat fluid from the heat fluid source, and when it is determined that the heat exchanger is not receiving heat fluid from the heat fluid source, control the operation of the hot water supply system to an initial hot water mode, which is used to supply hot water to the hot water outlet, the initial hot water mode including: o) Determine whether the heat storage medium contains sufficient heat to provide the required hot water; p) If the heat storage device stores sufficient heat, the system is controlled to transfer hot water from the heat storage device through the third flow path to the fifth flow path leading to the hot water outlet. q) If the heat storage device does not store sufficient heat, the system is controlled to transfer water from the heat exchanger through the fourth flow path, via the electric heater, to the fifth flow path, the electric heater being controlled to heat the water passing through it; and r) Repeat steps o)–q) whenever it is determined that hot water is needed at the domestic hot water outlet and the heat exchanger is not receiving hot fluid from the heat fluid source.

12. The method for controlling a domestic hot water supply system according to claim 10 or claim 11, wherein, Determining the temperature of the water input to the thermal storage appliance in steps e) and l) and / or determining whether sufficient heat is stored in the thermal storage medium in step o) includes using one or more temperature sensors located in or near the thermal storage medium and transmitting temperature signals from the one or more temperature sensors to the controller.

13. The method for controlling a domestic hot water supply system according to any one of claims 10 to 12, wherein, Determining whether hot water is needed at the domestic hot water outlet includes using one or more flow transducers located on or near the flow path leading to the hot water outlet, and transmitting flow signals from the one or more flow transducers to the controller.

14. The method for controlling a domestic hot water supply system according to any one of claims 10 to 12, wherein, Determining whether hot water is needed at the domestic hot water outlet includes using one or more pressure transducers located on or near the flow path leading to the hot water outlet, and transmitting pressure signals from the one or more pressure transducers to the controller.

15. A computer-readable medium storing instructions that, when executed by one or more processors of a controller, cause the controller to perform the method as described in any one of claims 10 to 14.

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