Method, system and apparatus for reducing energy consumption and water consumption

Abstract

A local hot water supply system comprising: a cold water inlet (302) for receiving cold water from a main water supply system; a hot water outlet (304) for providing hot water on demand to a local hot water outlet activated by a user; a heat exchanger (308) for heating water with the hot fluid received from the hot fluid source (306); an electric heater (326); a heat storage device (342) for storing heat; a circulation pump (320) for pumping water from the heat storage device (342) to the heat exchanger (308); and a controller (340) for controlling operation of the system, where the system is controlled to flow hot fluid received from the hot fluid source (306) to the heat exchanger (308) to transfer thermal energy of the hot fluid to hot water to flow the hot water to the hot water outlet (304); and, if it is determined that the temperature of the hot water at the hot water outlet (304) is above the desired temperature, the control system mixes the cold water from the cold water inlet (302) with the hot water from the heat exchanger (308) to reduce the temperature of the mixed water flowing to the hot water outlet (304).

Description

Technical Field

[0001] This disclosure relates to methods and apparatus suitable for facilities such as hot water supply systems in buildings, which help reduce energy and water consumption. Background Technology

[0002] Globally, the problem of drinking water shortages is becoming increasingly severe. Water scarcity is widely reported around the world, and while one might assume such problems only affect "hot" countries and regions, this is far from the truth. A report by the European Environment Agency states that water scarcity or water stress affects millions of people worldwide, including over 100 million in Europe. Approximately 88.2% of Europe's freshwater (including drinking and other uses) comes from rivers and groundwater, with the remainder from reservoirs (10.3%) and lakes (1.5%). This makes these water sources 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 uses 144 liters of fresh water per day for household consumption, but most of this water is wasted due to carelessness and improper selection of faucets, shower fixtures, and local appliances.

[0004] Along with the need to reduce water consumption comes the need to reduce household energy consumption, especially given that (at least in Europe) approximately 75% of heating and cooling still comes from fossil fuels, while only 22% comes from renewable energy sources.

[0005] According to EU Directive 2012 / 27 / EU, buildings account for 40% of the EU's final energy consumption and 36% of CO2 emissions. A 2016 report by the European Commission, "Mapping and Analysis of Heating / Cooling Fuel Deployment (Fossil Fuels / Renewable Energy) Current and Future (2020-2030)," indicates that heating and hot water alone account for 79% (192.5 million tonnes of oil equivalent) of total final energy consumption in EU households. The European Commission also reported that, "According to Eurostat data from 2019, approximately 75% of heating and cooling still comes from fossil fuels, while only 22% comes from renewable energy. To achieve the EU's climate and energy targets, the heating and cooling sector must significantly reduce energy consumption and fossil fuel use. Heat pumps (which utilize energy from air, soil, or water) have been identified as a potentially important approach to addressing this issue." Many countries have implemented policies and exerted pressure to reduce their carbon footprint. For example, in 2020, the UK government published a white paper on "Standards for the Future of Homes," proposing to reduce carbon emissions from new homes by 75% to 80% by 2025. Furthermore, in early 2019, the UK government announced a ban on gas-fired boilers in new homes from 2025. As of the time of writing, it was reported that 78% of total building heating energy consumption in the UK came from natural gas, while electricity accounted for only 12%.

[0006] The UK has a large number of small homes, typically with two or three bedrooms or less, and use gas-fired central heating systems. These homes mostly use what are known as modular boilers, which function as both instantaneous water heaters and central heating (space heating) boilers. Modular boilers are popular because of their compact size, ability to provide virtually unlimited instant hot water (output power of 20 to 35 kW), and the elimination of the need for a storage tank. These boilers can be purchased from reputable manufacturers at relatively low prices. Due to their small size and lack of a storage tank, they can often be installed even in small apartments or homes—usually mounted on the kitchen wall, and installation can be completed by one person in a day. Therefore, the cost of installing a new gas-fired modular boiler is not high. With the impending ban on new gas-fired boilers, people will need to find alternative heat sources for gas-fired modular boilers. Furthermore, previously installed gas-fired modular boilers will eventually need to be replaced with other types of boilers. The dimensions of a gas-fired modular boiler are typically: approximately 70 cm to 200 cm high, approximately 420 cm to 150 cm wide, and approximately 20 cm to 100 cm deep. The average dimensions of a typical indoor gas-fired combined boiler used in small to medium-sized residences are approximately 75 cm high, 45 cm wide, and 50 cm deep. Of course, these dimensions may vary depending on the manufacturer and the boiler's rated power.

[0007] With increasing public concern about the environmental impact of energy consumption, the use of heat pump technology to provide domestic hot water has garnered growing attention in recent years. A heat pump is a device that transfers heat energy from a heat source to a storage container. While heat pumps require electricity to complete this transfer, they are generally more efficient than resistance heaters (electric heating elements), typically boasting a coefficient of performance (COP) of at least 3 or 4. This means that, with the same electricity consumption, a heat pump can provide three to four times more heat to a user than a resistance heater.

[0008] The heat transfer medium that transfers heat energy is called a refrigerant. Heat energy is extracted from the air (e.g., outdoor air or air in a hot indoor room) or from a ground source (e.g., buried pipes or water injection wells) by a receiving heat exchanger and transferred to the stored refrigerant. Refrigerants with higher energy are compressed, their temperature rises significantly, and then the heat energy is transferred to the heated water circulation system via a heat exchanger. In terms of hot water supply, the heat extracted by the heat pump can be transferred to water in an insulated tank, which acts as a heat storage tank, allowing hot water to be used as needed. The hot water can then be delivered to one or more outlets as needed, such as faucets, shower heads, radiators, etc. However, compared to electric heaters, heat pumps typically take longer to heat water to the desired temperature.

[0009] While heat pumps are considered a potential solution for reducing reliance on fossil fuels and lowering CO2 emissions, they are currently unsuitable as a replacement for gas boilers in small homes (and small commercial properties) due to numerous technical, commercial, and practical reasons. Heat pumps are typically bulky, requiring a fairly large unit to be installed externally. Therefore, they are difficult to retrofit into homes already equipped with conventional gas boilers. Currently, a heat pump capable of providing the same output power as a conventional gas boiler is expensive and may require significant amounts of electricity. Not only are heat pumps themselves several times more expensive than equivalent gas boilers, but their size and complexity also mean complex and costly installation. Furthermore, the need for a hot water storage tank further hinders their application in small homes. Another technical issue is that heat pumps typically take a considerable amount of time to respond to demand and begin supplying heat, potentially requiring a 30-second self-check followed by additional time to heat up—there can be a delay of one minute or more between requesting hot water and receiving it. For this reason, renewable energy solutions using heat pumps and / or solar energy are generally only suitable for larger homes that require hot water storage tanks (which also present challenges such as space occupation, heat loss, and Legionnaires' disease risks).

[0010] A significant portion of household energy consumption stems from the use of hot water, manifested in both the amount of hot water used and the energy waste caused by overheating. Of course, hot water waste is also a major factor contributing to the more widespread problem of water waste, a problem that urgently needs to be addressed. Humanity must prioritize this issue if it desires a sustainable future.

[0011] Whether in commercial settings or homes, hot water is needed 24 / 7, year-round. Undoubtedly, a hot water supply requires clean water and a heat source. To provide hot water, centralized water supply systems are typically equipped with heating systems to heat the water to a preset temperature (such as a user-set temperature). Common heat sources are one or more electric heating elements or natural gas combustion. Generally, during peak energy demand periods (such as natural gas or electricity), utilities implement peak-hour pricing, increasing the price per unit of energy, partly to cover the cost of purchasing extra energy to meet customer demand and partly to curb unnecessary energy consumption. During off-peak periods, utilities implement off-peak pricing, reducing the price per unit of energy and encouraging customers to use electricity during off-peak hours rather than peak hours, thus achieving a more balanced energy consumption in the long run. However, these strategies are only effective if customers are always aware of the tariff changes and consciously strive to change their energy consumption habits.

[0012] Because different homes, workplaces, and commercial spaces have different needs and preferences for hot water use, new hot water supply methods are needed to make heat pumps a practical alternative to electric heaters. Summary of the Invention

[0013] This disclosure provides a hot water supply system as described in claim 1.

[0014] This disclosure also provides a method for controlling a hot water supply system, as described in claim 9.

[0015] This disclosure also provides a corresponding computer program product as described in claim 13. Attached Figure Description

[0016] Referring to the accompanying drawings, embodiments of various aspects of this disclosure will be described below by way of example only, wherein: Figure 1 This is a schematic diagram of an exemplary water supply system. Figure 2 This is a schematic diagram of a building water supply facility according to one aspect of this disclosure; Figure 3 Is with Figure 2 A partial schematic diagram of a similar building's water supply system, showing the components and flow paths; Figure 4 It shows Figure 3 The building's water supply facilities are shown, along with their first operating mode. Figure 5 It shows Figure 3 The building's water supply facilities are shown, along with its second operating mode. Figure 6 It shows Figure 3The building's water supply facilities are shown, along with its third operating mode. Figure 7 It shows Figure 3 The building's water supply facilities are shown, along with its fourth operating mode. Figure 8 It shows Figure 3 The building's water supply system is shown, along with its fifth operating mode. Figure 9 It shows Figure 3 The building's water supply facilities are shown, along with its sixth operating mode. Figure 10 It shows Figure 3 The building's water supply facilities are shown, along with its seventh operating mode. Figure 11 It shows Figure 3 The building's water supply facilities are shown, along with its eighth operating mode. Figure 12 It shows Figure 3 The building's water supply system is shown, along with its ninth operating mode. Detailed Implementation

[0017] When discussing household energy consumption, the energy consumption during the hot water supply process must be considered. This means taking into account not only the temperature of the supplied or stored water but also the amount of hot water used. Historically, many countries and regions considered to have abundant freshwater resources have paid little attention to household water consumption, largely due to the configuration of water supply systems and the flow rate at water outlets. It is not uncommon for bathtub faucets to flow more than 15 liters per minute, kitchen faucets to flow 12 liters or more per minute, and even washbasin faucets to flow 10 liters or more per minute. Shower outlets can also exceed 15 liters per minute, with about two-thirds typically coming from the hot water supply.

[0018] Over the past two decades, as people have become more aware of water scarcity and as public water providers have been privatized, with the introduction of local water meters and pay-as-you-go pricing, attitudes have shifted to some extent. Consequently, the maximum flow rate of faucets and showerheads in newly built homes is typically only half to two-thirds of that of older models. However, high-flow-rate faucets and showerheads are still prevalent not only in older homes, but even more modern faucets can easily lead to water consumption far exceeding what is needed for washing hands, bathing, or showering. For example, a 15-liter-per-minute shower consumes 180 liters of water, of which approximately 100 to 110 liters are hot water. Hot water temperatures are typically between 50 and 60 degrees Celsius—while the initial water temperature is usually no more than 10 degrees Celsius, and often even lower. Therefore, people realize that not only is a large amount of water consumed, but also a significant amount of energy is required to heat it.

[0019] In addition, while a hot water supply temperature of 50 to 60 degrees Celsius can help reduce the risk of Legionella infection, there is also a considerable risk of burns within this temperature range.

[0020] In embodiments of this disclosure, cold and hot water are supplied by a centralized water supply system to multiple outlets in a residential or commercial building, including faucets, showers, radiators, etc. Figure 1 An exemplary water supply system according to an embodiment is illustrated. In this illustrative system, the water supply system 100 includes a control module 110, which may include one or more machine learning algorithms 120. The control module 110 is communicatively coupled to various components of the water supply system and configured to control these components, such as a flow control element 130 (e.g., using one or more valves to control the water flow 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 heat storage device 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. Hot water, whether heated by the heat storage device 150 or the electric heating elements 160, can be delivered to one or more outlets as needed. In some embodiments, the heat pump 140 extracts ambient heat into a heat storage medium within the heat storage device 150. This heat storage medium can also be heated by other heat sources. Once the heat storage medium is heated to the desired operating temperature, it can be used to heat cold water (e.g., from the main water supply system) to the target temperature. The heated water can then be delivered to various outlets in the system.

[0021] In this illustrative system, the control module 110 is configured to receive inputs from multiple 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 indoor and / or outdoor air temperature sensors, one or more water temperature sensors, one or more water pressure sensors, one or more timers, one or more motion sensors, and may also include other sensors not directly connected to the water supply system 100, such as GPS signal receivers, calendars, weather forecast applications, etc. These applications may be installed on, for example, a user's smartphone and communicate with the control module via a communication channel. In this embodiment, the control module 110 is configured to use the received inputs to perform various control functions, such as controlling the water flow through the flow control element 130 to the heat storage device 150 or the electric heating element 160 to heat the water.

[0022] While heat pumps are generally more energy-efficient at heating water than electric heaters, they require startup time due to various checks and cycles before reaching normal operating conditions and the time needed to transfer sufficient heat to the storage medium to reach the desired operating temperature. Electric heaters, on the other hand, typically provide heat much faster. Therefore, a heat pump may take longer to heat the same amount of water to the same temperature compared to an electric heater.

[0023] Figure 2A more detailed schematic diagram of a hot water supply facility 200 within a building is shown. The hot water supply facility 200 has multiple controllable water outlets (various faucets and shower heads, described in detail later), a hot water supply device 205 (at least one of which has a controllable water temperature), and a water flow path located between the hot water supply device 205 and the multiple controllable water outlets. This water flow path includes at least one first temperature sensor 243 for detecting the water temperature, at least one flow measurement device 210, and at least one flow regulator 215. A processor 240 is operatively connected to the at least one flow measurement device 210 and the at least one flow regulator 215. The water supply facility shown represents a residence with a master bathroom 221, a first ensuite shower room 222, a second ensuite shower room 223, a toilet 224, and a kitchen 225. The master bathroom 221 and the first ensuite shower room 222 may be located on the same floor of the residence, while the toilet 224, the second ensuite shower room 223, and the kitchen 225 may be located on another floor. In this scenario, as shown in the diagram, it might be more convenient to set up two independent loops 230 and 231 to supply water to each outlet. These two loops 230 and 231 can be supplied by different outlets, the temperature of each outlet can be adjusted independently, and each outlet 1 is equipped with its own temperature sensor 243. The water temperature 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 input to the heat source (e.g., an electric heating element or even a gas heater). We will later discuss hot water systems incorporating thermal storage devices, which are typically used in conjunction with heat pumps. In such systems, the hot water supply temperature is usually adjusted by mixing different proportions of cold water from a cold water supply unit. Sometimes, such systems have an instantaneous heat source (e.g., an electric heating element) downstream of the thermal storage unit, controlled by a system processor. In such facilities, controlling the hot water supply temperature may involve controlling the energy supply to the instantaneous water heater, or it may involve mixing different proportions of cold water from a cold water supply unit.

[0024] As shown in the diagram, the main bathroom 221 includes a shower head 235, a bathtub faucet 236, and a sink faucet 237. Ensuite shower rooms 222 and 223 also include a shower head 235 and a sink faucet 237. In contrast, the toilet 224 contains only a toilet (not shown) and a sink with a faucet 238. Finally, the kitchen 235 features a sink with a faucet 239.

[0025] The processor or system controller 240 and its associated memory 241 are 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 circuits 230 and 231 is equipped with a flow measurement device 210 and a flow regulator 215. The processor may also be selectively connected to one or more temperature sensors 243, one for each circuit 230 and 231. The processor may be associated with an energy storage device.

[0026] The processor can also connect 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 connects to the Internet 244 to connect to a server or central station 245, and can also selectively connect to a cellular wireless network (e.g., LTE, UMTS, 4G, 5G, etc.). Through the RF transceiver 242 and / or the Internet connection, the processor 240 can communicate with a mobile device 250 (e.g., a smartphone or tablet) for installation engineers to configure (and optionally draw) wiring diagrams of the building's water supply facilities. The mobile device 250 includes software (e.g., a specific application) that works in conjunction with corresponding software in the system controller 240 and the server 245 to facilitate configuration (and optional mapping) methods according to embodiments of this disclosure, particularly for synchronizing operations taken by the engineer with the clocks of the system controller 240 / server 245. The memory 241 contains code enabling the processor to execute methods for configuring (and optionally mapping) the building's water supply facilities, for example, during the commissioning of a new facility.

[0027] During commissioning, to configure the hot water supply facility 200, engineers may need to install temperature sensors directly below specific hot water outlets (e.g., specific faucets or shower heads) and fully open those outlets at specific times. The system processor is configured to measure flow rate, the temperature difference between the outlet water temperature and the desired temperature, time delay, and (ideally) the outdoor temperature (data provided by an external temperature sensor). This allows algorithms (e.g., MLA) to calculate the heat loss of the distribution system, the distance between the outlet (faucet or shower head) and the hot water source, and ultimately precisely adjust the outlet water temperature so that the relevant controllable outlet (e.g., faucet) reaches the appropriate water temperature. For example, if there are children in the home, the maximum hot water temperature for all outlets except the kitchen sink might be limited to 40°C or 41°C; while if there is an infant in the home, the maximum temperature might be limited to 37°C. Even if there are no children in the home, the maximum temperature for all outlets except the kitchen sink could be set to 43°C, and the maximum temperature for the shower head might be set to 41°C.

[0028] This system can also be configured to restrict hot water flow to certain types of outlets, such as washbasins, sinks, and possibly showerheads. The maximum flow rate can be set differently for each type of outlet, or a specific maximum flow rate can be set for a particular outlet—for example, lower flow rates can be set for bathrooms and toilets used by children. The maximum temperature and flow rate settings can be based on rules provided by the system supplier. We will discuss hot water supply systems using heat pumps and thermal storage units later. These systems can greatly benefit from temperature and flow control—because heat pumps designed for the heating needs of medium-sized one- to three-bedroom homes often lack sufficient heating capacity to meet the instantaneous hot water needs of a household unless equipped with a large-capacity hot water storage tank. By controlling the hot water flow and temperature, the necessity of a hot water storage tank may be eliminated, while minimizing the energy gap that needs to be compensated for otherwise. If the facility does include thermal storage units and heat pumps, the system supplier will typically pre-set appropriate temperature and flow rate values ​​for the processor based on the outlet type and household composition.

[0029] The system controller has internet access to a database containing temperature (optional flow rate) data, which is based on outlet type and family composition and is updated regularly. The system controller's user interface provides residents and / or maintenance engineers with the ability to adjust settings according to changes in family composition—for example, when guests arrive with infants, children, or elderly / infirm individuals, users can set lower maximum temperatures and / or flow rates.

[0030] Figure 3 The heating system 300 is schematically shown in the figure, and is illustrated in relation to the above. Figure 1 Some components and flow paths between components may be used in systems similar to the described system. As shown in the figure, heating system 300 includes a main cold water inlet 302 and a local hot water outlet 304 (e.g., a faucet or shower head), and a local hot water heating device 310 (e.g., a radiator). System 300 also includes a heat pump 306 (with a typical heating capacity of 3-12 kW), a heat exchanger 308, and a heat storage device 342 (e.g., a small water tank with a capacity of approximately 15 liters). These components are connected by water pipes equipped with flow sensors, temperature sensors, and valves to control the flow of water through the pipes in a manner described below. Both the flow sensors and temperature sensors are connected via signal lines to provide signals to system controller 340. System controller 340 controls the valves, thereby enabling the system to operate in one of several operating modes as described below. One, some, or all of the flow sensors may be replaced by pressure sensors, which are used to measure fluid pressure to determine the flow rate.

[0031] A first flow path 312, extending from the main cold water inlet 302, leads to the first inlet HX1 of the heat exchanger 308. Temperature sensor TT01 and flow sensor FT01 measure the temperature and flow rate of the cold water at the main cold water inlet 302. Temperature sensor TT02 and flow sensor FT03 measure the temperature and flow rate at the first inlet HX1 of the heat exchanger 308. A second flow path 314 extends from the first flow path 312, near the main cold water inlet 302, to the local hot water outlet 304. A first electric valve MV01 is located in the second flow path 314 and is used to regulate the water flow rate within the second flow path 314. Flow sensor FT02 measures the flow rate of cold water flowing through the first electric valve MV01. After flowing out of the first electric valve MV01, the cold water selectively mixes with water flowing out of the electric three-way valve MV03 (as described further below) and flows to the local hot water outlet 304. Next to the local hot water outlet 304, temperature sensor TT07 measures the temperature of the water flowing to the local hot water outlet 304.

[0032] The first portion 316a of the third flow path 316 leads out from the first flow path 312 and is closer to the heat exchanger 308 than the second flow path 314. A second electric valve MV02 is located in the first portion 316a of the third flow path 316 and is used to regulate the water flow within this portion, which flows towards the lower part of the heat storage device 342. Temperature sensor TT11 measures the water temperature at the lower part of the heat storage device 342, and another temperature sensor TT10 measures the water temperature at the upper part of the heat storage device 342. The second portion 316b of the third flow path 316 leads out from the upper part of the heat storage device 342 and is connected to the second inlet B of the electric three-way valve MV03. Temperature sensor TT05 measures the water temperature in the second portion 315b of the third flow path 316. A return flow path 318 is provided to return water from the outlet of the electric valve MV02 in the first portion 316a of the third flow path 316 to the inlet of the electric valve MV02 via a circulation pump 320 and a check valve 322.

[0033] The first outlet HX2 of heat exchanger 308 receives water entering the heat exchanger via the first inlet HX1. A fourth flow path 324 extends from the first outlet HX2 of the heat exchanger via an electric heater 326 to the first inlet A of the electric three-way valve MV03. Temperature sensor TT03 measures the temperature of the water leaving the first outlet HX2 of heat exchanger 308, and temperature sensor TT04 measures the temperature of the water leaving the electric heater 326 and entering the first inlet A of the electric three-way valve MV03. A fifth flow path 328 flows from the outlet AB of the electric three-way valve MV03 to the local hot water outlet 304, and merges with the first flow path 314 before reaching the local hot water outlet 304. Temperature sensor TT06 measures the temperature of the water flowing out of the outlet AB of the electric three-way valve MV03 before merging with the water from the second flow path 314, and temperature sensor TT07 measures the temperature of the water entering the local hot water outlet 304 after merging with the water from the second flow path 314.

[0034] On the other side of heat exchanger 308, opposite to the first inlet HX1 and the first outlet HX2 are the second inlet HX3 and the second outlet HX4. The second inlet HX3 is supplied with water by a sixth flow path 330, which extends from the outlet of heat pump 306 via an electric three-way valve MV04. A temperature sensor TT08 measures the water temperature at the second inlet HX3 of heat exchanger 308. A seventh flow path 332 connects 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, used to heat the water at the inlet and discharge the heated water. A temperature sensor TT09 measures the temperature of the water leaving heat exchanger 308 and entering the inlet of heat pump 306. Therefore, the first inlet A of the electric three-way valve MV04 is connected to the outlet of heat pump 306, and the outlet AB is connected to the second inlet HX3 of heat exchanger 308. The second outlet B of the electric three-way valve MV04 leads to the inlet of the local hot water heating device 310, and the outlet of the device leads to the seventh flow path 332.

[0035] The dashed line 344 in the figure indicates all the components of the system, which can be installed in a housing similar in size and shape to a modular boiler. Those skilled in the art will understand that in some cases these components can be arranged differently inside or outside the housing, and in others this arrangement may be completely unnecessary. For example, the temperature sensor TT09 can be located inside the housing 344 near the heat exchanger 308, or outside the housing 344 near the local hot water heating unit 310. Other temperature and flow sensors, such as the flow sensor FT01 and / or the temperature sensor TT01, can also be arranged similarly inside or outside the housing as needed.

[0036] The following will be referenced Figures 4 to 12The operating modes of the heating system 300 are described in more detail. Figures 4 to 12 It shows Figure 3 The system is shown in the figure, but for clarity, the signal lines between the controller 340 and the various flow and temperature sensors, as well as the device itself, are omitted. Instead, superimposed dashed lines indicate the flow paths used in specific operating modes, illustrating which flow paths and components are controlled in that mode. The heating system 300 has several different operating modes, which will be described one by one below. Several operating modes may be interrelated and can be used in combination or individually. These modes include: Mode 1 ( Figure 4 ): Heat exchanger storage mode, wherein heat exchanger 308 is used to heat water, and the heated water is used to fill (or charge) the heat storage device 342; Mode 2 ( Figure 5 ): Electric heater heat storage mode, wherein the electric heater 326 is used to heat water, and the heated water is used to fill the heat storage device 342; Mode 3 ( Figure 6 ): Initial hot water mode, wherein the hot water supplied to the local hot water outlet 304 is provided by the heat storage device 342 (if it is already full of hot water), or by the electric heater 326, or a combination of both as needed; Mode 4 ( Figure 7 ): Mixed water mode, which mixes the water in mode 3 with the cold water from the main cold water inlet 302 to reduce the temperature of the water delivered to the local hot water outlet 304; Mode 5 ( Figure 8 ): Steady-state mode, wherein heat pump 306 is used to heat cold water from main cold water inlet 302 at heat exchanger and mix the heated water (optionally further heated by electric heater 326) with cold water from main cold water inlet 302 to reduce the temperature of the water delivered to local hot water outlet 304; Mode 6 ( Figure 9 ): Combination mode, which is a combination of mode 3 and mode 5; Mode 7 ( Figure 10 Heat pump defrosting mode; Mode 8 ( Figure 11 ): House heating mode; and Mode 9 ( Figure 12 ): The overall mode is a combination of mode 6 and mode 8.

[0037] First, refer to Figure 4The diagram illustrates the first operating mode (“heat pump storage mode”), in which the heat storage device 342 is filled with hot water supplied by the heat exchanger 308. In this first mode, the second electric valve MV02 is closed, and the circulation pump 320 in the return flow path 318 is activated, pumping water from the heat storage device 342 through the circulation pump 320, check valve 322, and first flow path 312 to the first inlet HX1 of the heat exchanger 308. Since the water is pumped into the first flow path 312 from the first portion 316a of the third flow path 316, water from the local cold water inlet 302 does not affect the water flow. The water is heated in the heat exchanger 308 and then flows from the first outlet HX2 through the fourth flow path 324, past the electric heater 326 (which is closed in this mode), to the electric valve MV03. The electric valve MV03 controls the water flow from port A to port B, returning the water to the heat storage device 342. Obviously, if necessary, the water can be circulated multiple times until the water temperature in the heat storage device 342 reaches a predetermined temperature, which is measured by temperature sensor TT10 or temperature sensor TT04. To supply hot water from the heat pump to the heat exchanger 308, the electric valve MV04 is controlled to allow water from the sixth flow path 330 of the heat pump 306 to flow through port A to port AB of the electric valve MV04, thereby entering 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.

[0038] In the first mode, the heat pump power is adjusted to transfer heat to the circulating hot water loop for heat storage in the heat storage device 342 (e.g., a 15-liter water tank), while the circulating pump 320 on the hot water side continues to operate. For example, if the circulating pump 320 operates at a flow rate of 6 liters per minute, 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 circulating pump 320 will run for approximately 6 minutes, allowing the water in the heat storage device 342 to reach 55°C after circulating twice in the loop.

[0039] Figure 5The second operating mode (“Electric Heater Storage Mode”) is demonstrated, in which the heat storage device 342 stores hot water heated by the electric heater 326. Similar to the first mode, in this mode, the second electric valve MV02 is closed, and the circulation pump 320 in the return flow path 318 is activated, pumping water from the heat storage device through the circulation pump 320, check valve 322, and first flow path 312 to the first inlet HX1 of the heat exchanger 308. In this mode, the heat pump does not supply heat to the heat exchanger, so water flows from the first outlet HX2 of the heat exchanger through the fourth flow path 324 to the electric heater 326, which is actively controlled by the system to heat the water in this mode. The hot water is then sent to the electric valve MV03, which controls the water flow from port A to port B, thus returning the hot water to the heat storage device 342. Clearly, if necessary, the water can be circulated in this way multiple times until the water in the heat storage device 342 reaches a predetermined temperature, measured by temperature sensor TT10 or temperature sensor TT04.

[0040] In the 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 flow rate of the circulation pump 320 is 5 liters / minute and the power of the electric heater 326 is adjusted to heat the water in the hot water circuit to 55°C (measured by the temperature sensor TT04), the circulation pump 320 will run for 6 minutes, heating the water in the heat storage device 342 to 55°C in two stages.

[0041] Therefore, the controller can choose to use either the first or second mode to store heat for the thermal storage device. This may depend on whether the heat pump is available and operational. If the heat pump is running and there is already hot water in the heat exchanger, the first mode can be selected. If the heat pump is running, but the electric valve MV04 is preventing hot water from flowing to the heat exchanger, the first mode can still be selected, and the electric valve MV04 can be controlled as described above to allow hot water to flow from port A to port AB, thereby reaching the second inlet HX3 of the heat exchanger. On the other hand, if the heat pump is not running, and as described above, it takes some time to start producing hot water, the controller can select the second mode, which uses an electric heater to heat the water to store heat for the thermal storage device.

[0042] In the third operating mode (“initial hot water mode”), such as Figure 6As shown, hot water is supplied to the local hot water outlet 304 by heating via a heat storage device 342 (if already filled with hot water) or an electric heater 326, or a combination of both. If the heat storage device 342 is already filled with hot water, the hot water in the heat storage device 342 is used preferentially over the electric heater 326. To use the hot water in the heat storage device 342, the electric valve MV02 is opened, allowing cold water to be introduced from the main cold water inlet 302 through the third flow path 316 to displace the hot water in the heat storage device 342. The hot water in the heat storage device 342 flows from port B to port AB via the electric valve MV03. As the water temperature from the heat storage device 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 rates at ports A-AB and B-AB are inversely proportional, thus keeping the flow rate of water flowing from port AB to the fifth flow path 328 leading to the local hot water outlet 304 constant. The flow rate is regulated based on the temperature detected by temperature sensor TT06, specifically whether the detected temperature is lower than the set temperature of temperature sensor TT06. Therefore, if the temperature at temperature sensor TT06 is lower than the desired temperature, the proportion of fluid allowed to flow from port B to port AB can be reduced from 100% to allow fluid to flow through port A, while reducing the flow rate from port B. At this time, the flow rate from port B is reduced and mixes with the flow rate from port A. Water flowing through port A of electric valve MV03 originates from the fourth flow path 324 and is heated as needed by electric heater 326 to bring the hot water temperature at ports AB to the desired temperature (detected by temperature sensor TT06). Water in the fourth flow path 324 flows through heat exchanger 308, and water in the fourth flow path 324 flows through the first flow path 312 from the main cold water inlet 302 to heat exchanger 308. This operating mode relies on pre-heat storage in the heat storage device 342, for example, through one of the first or second operating modes.

[0043] Normally, the water in the heat storage device 342 is filled to 1.25 times the volume of water needed to reach the desired temperature, which is sensed by temperature sensor TT07 and measured by temperature sensors TT11 and TT10. When there is a secondary hot water demand flow (measured by flow sensor FT01), water flows through the third flow path 316 into the heat storage device 342. The heat storage device 342 can be a tiered water tank with a volume of 15 liters, in which 15 liters of water enter at the temperature measured by temperature sensor TT01, and 15 liters of preheated water are discharged. The water loss in the tank is measured by reading the temperatures of temperature sensors TT10 and TT11, as well as knowing the amount of water flowing through the tank. V=t*(Q@FT01-Q@FT03-Q@FT02) Where V is the amount of water level drop in the tank; t represents time; Q@FT01 represents the flow rate measured at the flow sensor FT01; Q@FT02 represents the flow rate measured at the flow sensor FT02; Q@FT03 represents the flow rate measured at the flow sensor FT03.

[0044] When water flows from the tank and enters port B of the electric valve MV03, if, for any reason, the temperature at temperature sensor TT05 is lower than the required temperature at temperature sensor TT07, the electric heater 326 can be used to raise the temperature of the water flowing through the fourth flow path 324. At this time, the electric valve MV03 is controlled to at least partially open port A to allow at least a portion of the flow measured at flow sensor FT01 to flow through the fourth flow path 324 to the electric heater 326. By controlling the electric heater 326, the flow in the bypass portion of flow sensor FT03 can be heated from the temperature at temperature sensor TT03 to the temperature at temperature sensor TT04.

[0045] This mode is very useful when the heat pump 306 is not running or not fully running, i.e., when no hot fluid is being supplied to the heat exchanger 308. Of course, as the heat pump heats up, the fluid temperature begins to rise and can be delivered to the heat exchanger 308, thereby causing the water flowing through it to begin to rise in temperature (measured by the temperature sensor TT03), which in turn controls the heat supplied by the electric heater 326 to produce the desired appropriate temperature.

[0046] Figure 7 The fourth operating mode, the mixed water mode, is shown. In this mode, hot water from the thermal storage unit 342 and / or the electric heater 326 (as described above, provided according to the third operating mode) or the heat exchanger 308 (if it produces hot water according to the fifth mode) is mixed with cold water from the main cold water inlet 302 to reduce the water temperature delivered to the local hot water outlet 304. In this mode, regardless of whether the hot water leaving the AB port of the electric three-way valve MV03 is provided via the fourth flow path 324 through the heat exchanger 308 (regardless of whether the water is heated by the electric heater 326) or from the thermal storage unit 342, the temperature of the hot water leaving the AB port of the electric three-way valve MV03 is measured using the temperature sensor TT06. The temperature signal is sent to the system controller 340. Figures 4 to 12(Not shown in the image). Controller 340 then determines whether the temperature at temperature sensor TT06 is higher than the desired hot water temperature at local hot water outlet 304. If it is higher than the desired temperature, it opens electric valve MV01 to mix cold water from the second flow path 314 with hot water flowing from the AB port of electric three-way valve MV03 into the fifth flow path 328. The opening degree of electric valve MV01 depends on the cold water temperature at the main inlet 302 (measured by temperature sensor TT01) and the cold water flow rate at the main inlet 302 (measured by flow sensor FT01) to generate the required flow rate (measured by flow sensor FT02) in the second flow path 314 leading to the fifth flow path 328, thereby mixing the cold water from the second flow path 314 with the hot water in the fifth flow path 328 to produce the desired temperature, thus bringing the water temperature at local hot water outlet 304 to the desired temperature (measured by temperature sensor TT07). Appropriate control procedures executed by the controller will regulate this mixing during normal operation to prevent the water temperature at local hot water outlet 304 from deviating from the desired temperature.

[0047] First, this function serves as a safety measure to prevent scalding for users whose faucets or water pipes are not equipped with temperature safety valves. Second, the mixing function allows the heat storage device 342 to store water at a temperature higher than the desired outlet water temperature. Thus, when the system operates in a mode where the heat storage device 342 supplies hot water from the local hot water outlet 304, the high-temperature water mixes with the cold water from the main cold water inlet, thereby slowing down the water flow rate from the heat storage device 342 and correspondingly increasing its effective volume.

[0048] In the third operating mode, hot water is initially supplied by the heat storage device 342 or the electric heater 326 (or a combination of both). Once the heat pump reaches full load operation and supplies hot fluid to the heat exchanger 308, the fifth operating mode can be entered. Figure 8As shown, in steady-state mode, electric valve MV02 is closed, so there is no fluid flow between the third flow path 316 and the heat storage device 342. Electric heater 326 is operational and can be controlled by the controller. As described above, the mixing control in the fourth mode is also operational. Therefore, electric valve MV04 is controlled to allow water to flow from port A to port AB. In this mode, heat pump 306 actively supplies heating fluid through the sixth flow path 330, and electric valve MV04 is set to deliver fluid from port A to port AB, entering heat exchanger 308. The fluid temperature is determined by the measured secondary hot water demand flow rate and the set hot water temperature (measured by temperature sensor TT07). The water flowing through heat exchanger 308 is heated by the heat exchanger to the temperature measured by temperature sensor TT03. Therefore, the flow rate measured by flow sensor FT03, the temperature measured by temperature sensor TT02, and the temperature measured by temperature sensor TT03 can be used to determine the energy supplied by the heat pump and subsequently provide feedback to the heat pump to adjust the power output. If the temperature measured by temperature sensor TT03 is lower than the desired temperature measured by temperature sensor TT07, then the electric heater 326 is controlled to heat the water to the desired temperature measured by temperature sensor TT04. Obviously, since the water flows from port A to port AB through the electric valve MV03, the temperature measured by temperature sensor TT04 will be the same as the temperature measured by temperature sensor TT06. If the temperature measured by temperature sensor TT06 is higher than the desired temperature measured by temperature sensor TT07, then the cold water can be mixed with the hot water described in the fourth operating mode, that is, the hot water is mixed with the cold water from the main cold water inlet 302 to lower the water temperature delivered to the local hot water outlet 304.

[0049] Figure 9 The sixth operating mode is displayed, which is essentially a combination of the third mode (initial hot water mode) and the fifth mode (steady-state mode). Hot water is supplied by heat exchanger 308 or heat storage device 342. If the water temperature measured by temperature sensor TT06 is lower than the desired water temperature set by temperature sensor TT07, the water from heat exchanger 308 can be heated using electric heater 326. On the other hand, if the water temperature measured by temperature sensor TT06 is higher than the desired water temperature set by temperature sensor TT07, the cold water from the self-cooled cold water inlet 302 can be mixed with the hot water through the second flow path 314 to lower its temperature to the desired temperature.

[0050] In severe weather, heat pumps sometimes face the risk of freezing. In such cases, whether to defrost an already frozen heat pump or to prevent freezing when temperatures may drop below freezing, the controller can put the system into a seventh mode ("Heat Pump Defrost Mode"). Figure 10As shown, in the seventh operating mode, the second electric valve MV02 is closed, and the circulation pump 320 in the return flow path 318 is started, causing water to be pumped from the heat storage device 342 through the circulation pump 320, check valve 322, and first flow path 312 to the first inlet HX1 of the heat exchanger 308. Since the water is pumped into the first flow path 312 from the first part 316a of the third flow path 316, the water from the local cold water inlet 302 does not affect the water flow. The water flows from the first outlet HX2 through the fourth flow path 324, through the electric heater 326, to the electric valve MV03, which controls the water flow from port A to port B, causing the water to return to the heat storage device 342 and circulate again. The water entering from the first inlet HX1 of the heat exchanger 308 is controlled to be hot; the heat source can be the heat storage device, or more likely, the electric heater 326, or a combination of both, depending on the degree of hot water filling in the heat storage medium.

[0051] In the seventh mode, the electric heater starts and adjusts its power to transfer heat to the circulating hot water loop flowing through the heat storage device 342. The electric valve MV04 is controlled, causing water from the sixth flow path 330 of the heat pump 306 to flow through port A of the electric valve MV04 to port AB, and then into 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 described above, when water flows from the second inlet HX3 to the second outlet HX4 of the heat exchanger 308, it exchanges heat with the hot water flowing from the first inlet HX1 to the first outlet HX1 of the heat exchanger 308, thus being heated. The hot water returning to the heat pump 306 can then provide heat energy to the refrigerant loop of the heat pump 306, which is circulated again through the heat pump's compressor. The now warmer refrigerant can defrost the evaporator coils.

[0052] Figure 11 The eighth mode shown (“House Heating Mode”) assumes that local hot water outlet 304 (or any other hot water outlet) does not require hot water, and therefore this mode is specifically designed to provide hot water (e.g., water) for heating a residence or other building via radiators or a hot water underfloor heating system. In this mode, the heat pump actively generates hot water and controls the flow of hot water from port A to port B via an electric valve MV04, thereby delivering the hot water to the local hot water heating device 310, whose outlet then returns to the heat pump 306.

[0053] Figure 12The ninth mode is demonstrated; it is a combination of modes six and eight, and therefore also a combination of modes three (initial hot water), five (steady-state), and eight (house heating), allowing for the combination of these modes as needed. In this mode, the electric heater 326 is active and adjustable, and all four electric valves MV01, MV02, MV03, and MV04 are active and adjustable. In this mode, the heat pump 306 can provide heating (as described in mode eight above) or provide thermal energy to heat or preheat hot water at the heat exchanger 308. As described in mode six above, hot water is provided by the heat exchanger 308 or the thermal storage device 342. If the water temperature measured by temperature sensor TT06 is lower than the desired water temperature measured by temperature sensor TT07, the electric heater 326 can be used to raise the water temperature from the heat exchanger 308. On the other hand, if the water temperature measured by temperature sensor TT06 is higher than the required water temperature measured by temperature sensor TT07, cold water from the main cold water inlet 302 can be mixed into the hot water through the second flow path 314 to lower its temperature to the desired temperature. As described above, apart from the heat pump 306, the local hot water outlet 304, and the local hot water heating device 310, most of the system components are typically contained within a single housing (or casing) 344, the size and shape of which can be similar to that of a modular boiler. The housing 344 may include insulation material to reduce heat loss. Clearly, different operating modes can be used in combination or individually as needed, and are controlled by a controller.

Claims

1. A local hot water supply system, comprising: The cold water inlet is used to receive cold water from the main water supply system; A hot water outlet is used to provide hot water to the local hot water outlet activated by the user on demand, and is connected to the cold water inlet; A heat exchanger has an inlet connected to the cold water inlet and an outlet connected to the hot water outlet, the heat exchanger selectively heating the water between the inlet and the outlet using a heat fluid selectively received from a heat fluid source; Electric heaters are used for selectively heating water; A heat storage device, used to store heat, is connected to the hot water outlet; A circulating pump is used to pump water from the thermal storage device to the heat exchanger; The first flow path connects the cold water inlet and the water inlet of the heat exchanger; The second flow path connects the cold water inlet and the fifth flow path; The third flow path connects the heat storage device and the fifth flow path; The fourth flow path connects the outlet of the heat exchanger to the fifth flow path; The fifth flow path connects to the hot water outlet from the fourth and third flow paths; 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 hot water supply system to operate in one or more of the following operating modes: A steady-state mode is used to supply hot water to the hot water outlet, the steady-state mode including: a) Determine whether there is a demand for hot water at the local hot water outlet; if it is determined that there is a demand for hot water at the local hot water outlet, then: b) Determine whether the heat exchanger receives hot fluid from the heat fluid source; c) When it is determined that the heat exchanger has not received hot fluid from the heat fluid source, the system is controlled to transport the hot fluid received from the heat fluid source to the heat exchanger, thereby transferring the thermal energy of the hot fluid to the water between the inlet and outlet of the heat exchanger to generate hot water; d) Control the system to allow hot water to flow from the heat exchanger through the fourth flow path and through the fifth flow path to the hot water outlet; e) Determine the temperature of the hot water at the hot water outlet; f) If it is determined that the temperature of the hot water at the hot water outlet is higher than the desired temperature, the system is controlled to allow cold water to flow from the cold water inlet through the second flow path and mix with the hot water from the fourth flow path, thereby reducing the temperature of the mixed water flowing through the fifth flow path to the hot water outlet; and g) Repeat steps e) and f) to control the flow rate of cold water through the second flow path so that the temperature of the mixed water at the hot water outlet is equal to or lower than the desired temperature.

2. The local hot water supply system according to claim 1, wherein, When it is determined in step a) that there is a demand for hot water at the local hot water outlet, and in step b) it is determined that the heat exchanger has not received hot fluid from the heat source, the hot water supply system is controlled to operate in an initial hot water mode to provide hot water to the hot water outlet. The initial hot water mode includes: h) Determine whether the heat storage medium has stored enough heat to provide the required hot water; i) If the heat storage device has stored enough heat, control the system to make hot water flow from the heat storage device through the third flow path to the fifth flow path, so as to reach the hot water outlet; j) If the heat storage device does not store enough heat, the system is controlled to allow water to flow from the heat exchanger through the fourth flow path to the fifth flow path, and through a controlled electric heater, which heats the water flowing through it; and k) Repeat steps h)-j) as soon as it is determined that the local hot water outlet requires hot water and the heat exchanger is not receiving hot fluid from the heat fluid source.

3. The hot water supply system according to claim 2 further includes one or more temperature sensors located in or near the heat storage medium and coupled to the controller to transmit temperature signals to the controller, enabling the controller to determine in step h) whether the heat storage medium has stored sufficient heat.

4. The hot water supply system according to any one of claims 1 to 3 further includes one or more temperature sensors located at or near the hot water outlet and coupled to the controller to transmit a temperature signal to the controller, enabling the controller to determine the temperature of the hot water at the hot water outlet in step e).

5. The hot water supply system according to any one of claims 1 to 4 further includes one or more temperature sensors located in or near the heat exchanger and coupled to the controller to transmit a temperature signal to the controller, enabling the controller to determine in step b) whether the heat exchanger has received hot fluid from the heat fluid source.

6. The hot water supply system according to any one of claims 1 to 5 further includes one or more flow sensors located in or near the flow path leading to the hot water outlet, coupled to the controller to transmit a flow signal to the controller, enabling the controller to determine whether there is a demand for hot water at the local hot water outlet.

7. The hot water supply system according to any one of claims 1 to 5 further includes one or more pressure sensors located in or near the flow path leading to the hot water outlet, coupled to the controller to transmit a pressure signal to the controller, enabling the controller to determine whether there is a demand for hot water at the local hot water outlet.

8. The hot water supply system according to any one 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 all contained within a housing.

9. The hot water supply system according to claim 8, wherein the floor area of ​​the casing is similar to that of a local combined boiler.

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

11. The hot water supply system according to claim 10, wherein the dimensions of the housing are approximately 75 cm high, 45 cm wide, and 50 cm deep.

12. A method for controlling a local hot water supply system, the local hot water supply system comprising: The cold water inlet is used to receive cold water from the main water supply system; A hot water outlet is used to provide hot water to the local hot water outlet activated by the user on demand, and is connected to the cold water inlet; A heat exchanger has an inlet connected to the cold water inlet and an outlet connected to the hot water outlet, the heat exchanger selectively heating the water between the inlet and the outlet using a heat fluid selectively received from a heat fluid source; Electric heaters are used for selectively heating water; A heat storage device, used to store heat, is connected to the hot water outlet; A circulating pump is used to pump water from the thermal storage device to the heat exchanger; The first flow path connects the cold water inlet and the water inlet of the heat exchanger; The second flow path connects the cold water inlet and the fifth flow path; The third flow path connects the heat storage device and the fifth flow path; The fourth flow path connects the outlet of the heat exchanger to the fifth flow path; The fifth flow path connects to the hot water outlet from the fourth and third flow paths; as well as The controller is coupled to the heat exchanger, the electric heater, the heat storage device, and the circulating pump; The method includes controlling the hot water supply system to operate in one or more of the following operating modes via a controller: A steady-state mode is used to supply hot water to the hot water outlet, the steady-state mode including: a) Determine whether there is a demand for hot water at the local hot water outlet; if it is determined that there is a demand for hot water at the local hot water outlet, then: b) Determine whether the heat exchanger receives hot fluid from the heat fluid source so that the heat energy of the hot fluid can be used to heat water in the heat exchanger; c) When it is determined that the heat exchanger has not received hot fluid from the heat fluid source, the system is controlled to transport the hot fluid received from the heat fluid source to the heat exchanger, thereby transferring the thermal energy of the hot fluid to the water between the inlet and outlet of the heat exchanger to generate hot water; d) Control the system to allow hot water to flow from the heat exchanger through the fourth flow path and through the fifth flow path to the hot water outlet; e) Determine the temperature of the hot water at the hot water outlet; f) If it is determined that the temperature of the hot water at the hot water outlet is higher than the desired temperature, the system is controlled to allow cold water to flow from the cold water inlet through the second flow path and mix with the hot water from the fourth flow path, thereby reducing the temperature of the mixed water flowing through the fifth flow path to the hot water outlet; and g) Repeat steps e) and f) to control the flow rate of cold water through the second flow path so that the temperature of the mixed water at the hot water outlet is equal to or lower than the desired temperature.

13. The method for controlling a local hot water supply system according to claim 12, wherein, When it is determined in step a) that there is a demand for hot water at the local hot water outlet, and in step b) it is determined that the heat exchanger has not received hot fluid from the heat source, the hot water supply system is controlled to operate in an initial hot water mode to provide hot water to the hot water outlet. The initial hot water mode includes: h) Determine whether the heat storage medium has stored enough heat to provide the required hot water; i) If the heat storage device has stored enough heat, control the system to make hot water flow from the heat storage device through the third flow path to the fifth flow path, so as to reach the hot water outlet; j) If the heat storage device does not store enough heat, the system is controlled to allow water to flow from the heat exchanger through the fourth flow path to the fifth flow path, and through a controlled electric heater, which heats the water flowing through it; and f) If it is determined that the local hot water outlet requires hot water and the heat exchanger is not receiving hot fluid from the heat fluid source, repeat steps h)-j).

14. The method for controlling a local hot water supply system according to claim 12, wherein determining whether the heat storage medium has stored sufficient heat in step h) comprises: One or more temperature sensors are used, located within or near the heat storage medium, and temperature signals from the one or more temperature sensors are transmitted to the controller.

15. The method for controlling a local hot water supply system according to any one of claims 11 to 14, wherein determining whether the heat exchanger receives hot fluid from the heat fluid source in step b) comprises: One or more temperature sensors are used, located inside or near the heat exchanger, and the temperature signal is transmitted to the controller.

16. The method for controlling a local hot water supply system according to any one of claims 11 to 15, wherein determining the temperature of the hot water at the hot water outlet in step e) comprises: One or more temperature sensors are used at or near the hot water outlet, and temperature signals from the one or more temperature sensors are transmitted to the controller.

17. The method for controlling a local hot water supply system according to any one of claims 11 to 16, wherein determining whether there is a demand for hot water at the local hot water outlet comprises: One or more flow sensors are used in or near the flow path leading to the hot water outlet, and flow signals from the one or more flow sensors are transmitted to the controller.

18. The method for controlling a local hot water supply system according to any one of claims 11 to 16, wherein determining whether there is a demand for hot water at the local hot water outlet comprises: One or more pressure sensors are used in or near the flow path leading to the hot water outlet, and pressure signals from the one or more pressure sensors are transmitted to the controller.

19. A computer-readable medium having instructions stored thereon that, when executed by one or more processors of a controller, cause the controller to perform the method of any one of claims 11 to 17.

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