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CN-116804466-B - System and method for providing domestic hot water and/or space heating in a building

CN116804466BCN 116804466 BCN116804466 BCN 116804466BCN-116804466-B

Abstract

The present invention provides systems and methods for providing domestic hot water and/or space heating within a building. The system may be used in the method and is characterized by comprising a1 st storage device comprising a1 st phase change material, a1 st detector for determining a charge state of the 1 st storage device, and a1 st phase change material heat exchanger adapted to exchange heat between refrigerant from a refrigeration circuit and the 1 st phase change material. The system further includes a2 nd storage device containing a2 nd phase change material, a2 nd detector for determining a charge state of the 2 nd storage device, and a2 nd phase change material heat exchanger adapted to exchange heat between the 2 nd phase change material and water of a thermal medium circuit. A controller is configured to control operation of the system based at least on the charge state of the 1 st storage device and the charge state of the 2 nd storage device.

Inventors

  • JAMES FREEMAN
  • Christopher Orkis
  • Georgiana Kavalley
  • WU DUAN

Assignees

  • 三菱电机株式会社

Dates

Publication Date
20260508
Application Date
20230317
Priority Date
20220325

Claims (16)

  1. 1. A system for providing Domestic Hot Water (DHW) and/or Space Heating (SH) within a building, the system comprising: a) A refrigeration circuit, the refrigeration circuit comprising: As the refrigerant of the heat medium, A compressor (1), A1 st expansion valve (2) and a2 nd expansion valve (2'), A1 st three-way valve (13) and a2 nd three-way valve (14), A four-way switching valve (3), An outdoor heat exchanger (4) adapted to exchange heat between the refrigerant and air, and A 1 st storage device (5), the 1 st storage device comprising a 1 st phase change material, wherein the 1 st storage device (5) comprises a 1 st detector for determining a charge state (SOC 1 ) of the 1 st storage device (5) and comprises a 1 st phase change material heat exchanger (6) adapted to exchange heat between the refrigerant and the 1 st phase change material; b) A thermal medium circuit, the thermal medium circuit comprising: as the water to be used as the heat medium, A2 nd storage device (7) thermally connected to the domestic hot water circuit and comprising a2 nd phase change material, wherein the phase change temperature of the 2 nd phase change material is higher than the phase change temperature of the 1 st phase change material, wherein the 2 nd storage device (7) comprises a2 nd detector for determining a state of charge (SOC 2 ) of the 2 nd storage device (7) and comprises a2 nd phase change material heat exchanger (8) adapted for heat exchange between water of the hot medium circuit and the 2 nd phase change material, A 3 rd three-way valve (9), said 3 rd three-way valve being adapted to switch the water flow to at least one radiator for space heating in a building or to said 2 nd phase change material heat exchanger (8), and At least one conveying mechanism (10) for circulating water through the heat medium heat exchanger; c) A heat medium heat exchanger (11) constituted by the refrigeration circuit and the heat medium circuit and adapted to transfer heat between the refrigerant and water, and D) A controller (12) configured to control operation of the system based at least on a state of charge (SOC 1 ) of the 1 st storage device (5) determined from information obtained from the 1 st detector and a state of charge (SOC 2 ) of the 2 nd storage device (7) determined from information obtained from the 2 nd detector.
  2. 2. The system of claim 1, wherein the system further comprises a controller configured to control the controller, The 1 st storage device (5) is located outdoors and located in a heat pump outdoor unit, and the heat pump outdoor unit comprises the compressor (1), the 1 st expansion valve (2), the 2 nd expansion valve (2'), the 1 st three-way valve (13), the 2 nd three-way valve (14), the four-way switching valve (3), the outdoor heat exchanger (4) and the heat medium heat exchanger (11).
  3. 3. The system according to claim 1 or 2, wherein, The controller (12) is configured to: If defrosting of the outdoor heat exchanger (4) is required, Heat from the 1 st phase change material heat exchanger (6) is allowed to be transferred to the outdoor heat exchanger (4), Wherein the controller (12) is configured to: i) Setting the four-way switching valve (3) to a position that allows refrigerant to flow from the 1 st phase change material heat exchanger (6) to the outdoor heat exchanger (4) via the compressor (1); ii) setting the 1 st three-way valve (13) to direct refrigerant from the 1 st phase change material heat exchanger (6) to the compressor (1); iii) Setting the 2 nd three-way valve (14) to guide the refrigerant from the compressor (1) to the outdoor heat exchanger (4), and Iv) adjusting the orifice of the 1 st expansion valve (2) and the orifice of the 2 nd expansion valve (2') in combination to control evaporator superheat and compressor subcooling.
  4. 4. The system according to claim 1 or 2, wherein, The controller (12) is configured to: if defrosting of the outdoor heat exchanger (4) is not required, If the determined state of charge (SOC 2 ) of the 2 nd storage device (7) is below a set lower limit (LL 2 ), and If the determined state of charge (SOC 1 ) of the 1 st storage device (5) is below a set lower limit (LL 1 ), or if the determined outdoor air temperature (T OA ) is at or above a set lower limit (LL TOA ) of outdoor ambient air temperature, Then heat from the outdoor heat exchanger (4) is allowed to be transferred to the heat medium heat exchanger (11), particularly before the determined state of charge (SOC 2 ) of the 2 nd storage device (7) is at or above a set upper limit (UL 2 ), Wherein the controller (12) is configured such that, in particular before the determined state of charge (SOC 2 ) of the 2 nd storage device is at or above a set upper limit (UL 2 ), I) Setting the four-way switching valve (3) to a position that allows refrigerant to flow from the outdoor heat exchanger (4) to the heat medium heat exchanger (11) via the compressor (1); ii) setting the 1 st three-way valve (13) to direct refrigerant from the compressor (1) to the heat medium heat exchanger (11); iii) -setting the 2 nd three-way valve (14) to direct refrigerant from the outdoor heat exchanger (4) to the compressor (1); iv) adjusting the orifice of the 1 st expansion valve (2) and the orifice of the 2 nd expansion valve (2') in combination to control evaporator superheat and compressor subcooling, and V) setting the 3 rd three-way valve (9) to direct water to the 2 nd phase change material heat exchanger (8).
  5. 5. The system according to claim 1 or 2, wherein, The controller (12) is configured to: if defrosting of the outdoor heat exchanger (4) is not required, If the determined state of charge (SOC 2 ) of the 2 nd storage device is below a set lower limit (LL 2 ), and If the determined state of charge (SOC 1 ) of the 1 st storage device (5) is at or above a set lower limit (LL 1 ), and if the determined outdoor air temperature (T OA ) is below a set lower limit (LL TOA ) of outdoor ambient air temperature, Then heat from the 1 st phase change material heat exchanger (6) is allowed to transfer to the heat medium heat exchanger (11), in particular before the determined state of charge (SOC 2 ) of the 2 nd storage device (7) is at or above a set upper limit (UL 2 ), Wherein the controller (12) is designed such that, in particular before the determined state of charge (SOC 2 ) of the 2 nd storage device (7) is at or above a set upper limit (UL 2 ), I) Setting the four-way switching valve (3) to a position that allows refrigerant to flow from the 1 st phase change material heat exchanger (6) to the heat medium heat exchanger (11) via the compressor (1); ii) setting the 1 st three-way valve (13) to direct refrigerant from the compressor (1) to the heat medium heat exchanger (11); iii) -setting the 2 nd three-way valve (14) to direct refrigerant from the 1 st phase change material heat exchanger (6) to the compressor (1); iv) adjusting the orifice of the 1 st expansion valve (2) and the orifice of the 2 nd expansion valve (2') in combination to control evaporator superheat and compressor subcooling, and V) setting the 3 rd three-way valve (9) to direct water to the 2 nd phase change material heat exchanger (8).
  6. 6. The system according to claim 1 or 2, wherein, The controller (12) is configured to: if defrosting of the outdoor heat exchanger (4) is not required, If the determined state of charge (SOC 2 ) of the 2 nd storage device (7) is at or above a set lower limit (LL 2 ), If there is a Space Heating (SH) demand in the building, and If the determined state of charge (SOC 1 ) of the 1 st storage device (5) is below a set lower limit (LL 1 ), or if the determined outdoor air temperature (T OA ) is at or above a set lower limit (LL TOA ) of outdoor ambient air temperature, Heat from the outdoor heat exchanger (4) is allowed to be transferred to the heat medium heat exchanger (11), Wherein the controller (12) is configured to: i) Setting the four-way switching valve (3) to a position that allows refrigerant to flow from the outdoor heat exchanger (4) to the heat medium heat exchanger (11) via the compressor (1); ii) setting the 1 st three-way valve (13) to direct refrigerant from the compressor (1) to the heat medium heat exchanger (11); iii) -setting the 2 nd three-way valve (14) to direct refrigerant from the outdoor heat exchanger (4) to the compressor (1); iv) adjusting the orifice of the 1 st expansion valve (2) and the orifice of the 2 nd expansion valve (2') in combination to control evaporator superheat and compressor subcooling, and V) setting the 3 rd three-way valve (9) to direct water to at least one radiator for space heating within a building.
  7. 7. The system according to claim 1 or 2, wherein, The controller (12) is configured to: if defrosting of the outdoor heat exchanger (4) is not required, If the determined state of charge (SOC 2 ) of the 2 nd storage device (7) is at or above a set lower limit (LL 2 ), If there is a Space Heating (SH) demand in the building, and If the determined state of charge (SOC 1 ) of the 1 st storage device (5) is at or above a set lower limit (LL 1 ), and if the determined outdoor air temperature (T OA ) is below a set lower limit (LL TOA ) of outdoor ambient air temperature, Then heat from the 1 st phase change material heat exchanger (6) is allowed to transfer to the heat medium heat exchanger (11), in particular before the determined state of charge (SOC 2 ) of the 2 nd storage device (7) is at or above a set upper limit (UL 2 ), Wherein the controller (12) is designed such that, in particular before the determined state of charge (SOC 2 ) of the 2 nd storage device (7) is at or above a set upper limit (UL 2 ), I) Setting the four-way switching valve (3) to a position that allows refrigerant to flow from the 1 st phase change material heat exchanger (6) to the heat medium heat exchanger (11) via the compressor (1); ii) setting the 1 st three-way valve (13) to direct refrigerant from the compressor (1) to the heat medium heat exchanger (11); iii) -setting the 2 nd three-way valve (14) to direct refrigerant from the 1 st phase change material heat exchanger (6) to the compressor (1); iv) adjusting the orifice of the 1 st expansion valve (2) and the orifice of the 2 nd expansion valve (2') in combination to control evaporator superheat and compressor subcooling, and V) setting the 3 rd three-way valve (9) to direct water to at least one radiator for space heating within a building.
  8. 8. The system according to claim 1 or 2, wherein, The controller (12) is configured to: if defrosting of the outdoor heat exchanger (4) is not required, If the determined state of charge (SOC 2 ) of the 2 nd storage device (7) is at or above a set lower limit (LL 2 ), If there is no Space Heating (SH) requirement in the building, and If the determined state of charge (SOC 1 ) of the 1 st storage device (5) is below a set lower limit (LL 1 ), Then heat from the outdoor heat exchanger (4) is allowed to transfer to the 1 st phase change material heat exchanger (6), particularly before the determined state of charge (SOC 2 ) of the 2 nd storage device (7) is at or above a set upper limit (UL 2 ), Wherein the controller (12) is designed such that, in particular before the determined state of charge (SOC 2 ) of the 2 nd storage device (7) is at or above a set upper limit (UL 2 ), I) Setting the four-way switching valve (3) to a position that allows refrigerant to flow from the outdoor heat exchanger (4) to the 1 st phase change material heat exchanger (6) via the compressor (1); ii) setting the 1 st three-way valve (13) to direct refrigerant from the compressor (1) to the 1 st phase change material heat exchanger (6); iii) -setting the 2 nd three-way valve (14) to direct refrigerant from the outdoor heat exchanger (4) to the compressor (1); iv) adjusting the orifice of the 1 st expansion valve (2) and the orifice of the 2 nd expansion valve (2') in combination to control evaporator superheat and compressor subcooling.
  9. 9. A method for providing Domestic Hot Water (DHW) and/or Space Heating (SH) within a building, the method comprising: a) Providing a system, the system comprising: a refrigeration circuit, the refrigeration circuit comprising: As the refrigerant of the heat medium, A compressor (1), A1 st expansion valve (2) and a2 nd expansion valve (2'), A1 st three-way valve (13) and a2 nd three-way valve (14), A four-way switching valve (3), An outdoor heat exchanger (4) adapted to exchange heat between the refrigerant and air, and A 1 st storage device (5), the 1 st storage device comprising a 1 st phase change material, wherein the 1 st storage device (5) comprises a 1 st detector for determining a charge state (SOC 1 ) of the 1 st storage device (5) and comprises a 1 st phase change material heat exchanger (6) adapted to exchange heat between the refrigerant and the 1 st phase change material; a thermal medium circuit, the thermal medium circuit comprising: as the water to be used as the heat medium, A2 nd storage device (7) thermally connected to the domestic hot water circuit and comprising a2 nd phase change material, wherein the phase change temperature of the 2 nd phase change material is higher than the phase change temperature of the 1 st phase change material, wherein the 2 nd storage device (7) comprises a2 nd detector for determining a state of charge (SOC 2 ) of the 2 nd storage device (7) and comprises a2 nd phase change material heat exchanger (8) adapted for heat exchange between water of the hot medium circuit and the 2 nd phase change material, A 3 rd three-way valve (9), said 3 rd three-way valve being adapted to switch the water flow to at least one radiator for space heating in a building or to said 2 nd phase change material heat exchanger (8), and At least one conveying mechanism (10) for circulating water through the heat medium heat exchanger; A heat medium heat exchanger (11) constituted by the refrigeration circuit and the heat medium circuit and adapted to transfer heat between the refrigerant and water, and A controller (12), B) The operation of the system is controlled based on at least the state of charge (SOC 1 ) of the 1 st storage device (5) determined from the information obtained from the 1 st detector and the state of charge (SOC 2 ) of the 2 nd storage device (7) determined from the information obtained from the 2 nd detector.
  10. 10. The method of claim 9, wherein the step of determining the position of the substrate comprises, The 1 st storage device (5) is located outdoors and located in a heat pump outdoor unit, and the heat pump outdoor unit comprises the compressor (1), the 1 st expansion valve (2), the 2 nd expansion valve (2'), the 1 st three-way valve (13), the 2 nd three-way valve (14), the four-way switching valve (3), the outdoor heat exchanger (4) and the heat medium heat exchanger (11).
  11. 11. The method according to claim 9 or 10, wherein, If defrosting of the outdoor heat exchanger (4) is required, Heat from the 1 st phase change material heat exchanger (6) is allowed to be transferred to the outdoor heat exchanger (4), The method comprises the following steps of: i) Setting the four-way switching valve (3) to a position that allows refrigerant to flow from the 1 st phase change material heat exchanger (6) to the outdoor heat exchanger (4) via the compressor (1); ii) setting the 1 st three-way valve (13) to direct refrigerant from the 1 st phase change material heat exchanger (6) to the compressor (1); iii) Setting the 2 nd three-way valve (14) to guide the refrigerant from the compressor (1) to the outdoor heat exchanger (4), and Iv) adjusting the orifice of the 1 st expansion valve (2) and the orifice of the 2 nd expansion valve (2') jointly to control evaporator superheat and compressor subcooling.
  12. 12. The method according to claim 9 or 10, wherein, If defrosting of the outdoor heat exchanger (4) is not required, If the determined state of charge (SOC 2 ) of the 2 nd storage device (7) is below a set lower limit (LL 2 ), and If the determined state of charge (SOC 1 ) of the 1 st storage device (5) is below a set lower limit (LL 1 ), or if the determined outdoor air temperature (T OA ) is at or above a set lower limit (LL TOA ) of outdoor ambient air temperature, Then heat from the outdoor heat exchanger (4) is allowed to be transferred to the heat medium heat exchanger (11), particularly before the determined state of charge (SOC 2 ) of the 2 nd storage device (7) is at or above a set upper limit (UL 2 ), Wherein the method comprises the steps of, in particular, before the determined state of charge (SOC 2 ) of the 2 nd storage device is at or above a set upper limit (UL 2 ), I) Setting the four-way switching valve (3) to a position that allows refrigerant to flow from the outdoor heat exchanger (4) to the heat medium heat exchanger (11) via the compressor (1); ii) setting the 1 st three-way valve (13) to direct refrigerant from the compressor (1) to the heat medium heat exchanger (11); iii) -setting the 2 nd three-way valve (14) to direct refrigerant from the outdoor heat exchanger (4) to the compressor (1); iv) adjusting the orifice of the 1 st expansion valve (2) and the orifice of the 2 nd expansion valve (2') in combination to control evaporator superheat and compressor subcooling, and V) setting the 3 rd three-way valve (9) to direct water to the 2 nd phase change material heat exchanger (8).
  13. 13. The method according to claim 9 or 10, wherein, If defrosting of the outdoor heat exchanger (4) is not required, If the determined state of charge (SOC 2 ) of the 2 nd storage device (7) is below a set lower limit (LL 2 ), and If the determined state of charge (SOC 1 ) of the 1 st storage device (5) is at or above a set lower limit (LL 1 ), and if the determined outdoor air temperature (T OA ) is below a set lower limit (LL TOA ) of outdoor ambient air temperature, Then heat from the 1 st phase change material heat exchanger (6) is allowed to transfer to the heat medium heat exchanger (11), in particular before the determined state of charge (SOC 2 ) of the 2 nd storage device (7) is at or above a set upper limit (UL 2 ), Wherein the method comprises the steps of, in particular, before the determined state of charge (SOC 2 ) of the 2 nd storage means (7) is at or above a set upper limit (UL 2 ), I) Setting the four-way switching valve (3) to a position that allows refrigerant to flow from the 1 st phase change material heat exchanger (6) to the heat medium heat exchanger (11) via the compressor (1); ii) setting the 1 st three-way valve (13) to direct refrigerant from the compressor (1) to the heat medium heat exchanger (11); iii) -setting the 2 nd three-way valve (14) to direct refrigerant from the 1 st phase change material heat exchanger (6) to the compressor (1); iv) adjusting the orifice of the 1 st expansion valve (2) and the orifice of the 2 nd expansion valve (2') in combination to control evaporator superheat and compressor subcooling, and V) setting the 3 rd three-way valve (9) to direct water to the 2 nd phase change material heat exchanger (8).
  14. 14. The method according to claim 9 or 10, wherein, If defrosting of the outdoor heat exchanger (4) is not required, If the determined state of charge (SOC 2 ) of the 2 nd storage device (7) is at or above a set lower limit (LL 2 ), If there is a Space Heating (SH) demand in the building, and If the determined state of charge (SOC 1 ) of the 1 st storage device (5) is below a set lower limit (LL 1 ), or if the determined outdoor air temperature (T OA ) is at or above a set lower limit (LL TOA ) of outdoor ambient air temperature, Heat from the outdoor heat exchanger (4) is allowed to be transferred to the heat medium heat exchanger (11), The method comprises the following steps of: i) Setting the four-way switching valve (3) to a position that allows refrigerant to flow from the outdoor heat exchanger (4) to the heat medium heat exchanger (11) via the compressor (1); ii) setting the 1 st three-way valve (13) to direct refrigerant from the compressor (1) to the heat medium heat exchanger (11); iii) -setting the 2 nd three-way valve (14) to direct refrigerant from the outdoor heat exchanger (4) to the compressor (1); iv) adjusting the orifice of the 1 st expansion valve (2) and the orifice of the 2 nd expansion valve (2') in combination to control evaporator superheat and compressor subcooling, and V) setting the 3 rd three-way valve (9) to direct water to at least one radiator for space heating within a building.
  15. 15. The method according to claim 9 or 10, wherein, If defrosting of the outdoor heat exchanger (4) is not required, If the determined state of charge (SOC 2 ) of the 2 nd storage device (7) is at or above a set lower limit (LL 2 ), If there is a Space Heating (SH) demand in the building, and If the determined state of charge (SOC 1 ) of the 1 st storage device (5) is at or above a set lower limit (LL 1 ), and if the determined outdoor air temperature (T OA ) is below a set lower limit (LL TOA ) of outdoor ambient air temperature, Then heat from the 1 st phase change material heat exchanger (6) is allowed to transfer to the heat medium heat exchanger (11), in particular before the determined state of charge (SOC 2 ) of the 2 nd storage device (7) is at or above a set upper limit (UL 2 ), Wherein the method comprises the steps of, in particular, before the determined state of charge (SOC 2 ) of the 2 nd storage means (7) is at or above a set upper limit (UL 2 ), I) Setting the four-way switching valve (3) to a position that allows refrigerant to flow from the 1 st phase change material heat exchanger (6) to the heat medium heat exchanger (11) via the compressor (1); ii) setting the 1 st three-way valve (13) to direct refrigerant from the compressor (1) to the heat medium heat exchanger (11); iii) -setting the 2 nd three-way valve (14) to direct refrigerant from the 1 st phase change material heat exchanger (6) to the compressor (1); iv) adjusting the orifice of the 1 st expansion valve (2) and the orifice of the 2 nd expansion valve (2') in combination to control evaporator superheat and compressor subcooling, and V) setting the 3 rd three-way valve (9) to direct water to at least one radiator for space heating within a building.
  16. 16. The method according to claim 9 or 10, wherein, If defrosting of the outdoor heat exchanger (4) is not required, If the determined state of charge (SOC 2 ) of the 2 nd storage device (7) is at or above a set lower limit (LL 2 ), If there is no Space Heating (SH) requirement in the building, and If the determined state of charge (SOC 1 ) of the 1 st storage device (5) is below a set lower limit (LL 1 ), Then heat from the outdoor heat exchanger (4) is allowed to transfer to the 1 st phase change material heat exchanger (6), particularly before the determined state of charge (SOC 2 ) of the 2 nd storage device (7) is at or above a set upper limit (UL 2 ), Wherein the method comprises the steps of, in particular, before the determined state of charge (SOC 2 ) of the 2 nd storage means (7) is at or above a set upper limit (UL 2 ), I) Setting the four-way switching valve (3) to a position that allows refrigerant to flow from the outdoor heat exchanger (4) to the 1 st phase change material heat exchanger (6) via the compressor (1); ii) setting the 1 st three-way valve (13) to direct refrigerant from the compressor (1) to the 1 st phase change material heat exchanger (6); iii) -setting the 2 nd three-way valve (14) to direct refrigerant from the outdoor heat exchanger (4) to the compressor (1); iv) adjusting the orifice of the 1 st expansion valve (2) and the orifice of the 2 nd expansion valve (2') jointly to control evaporator superheat and compressor subcooling.

Description

System and method for providing domestic hot water and/or space heating in a building Technical Field The present invention provides a system and method for providing domestic hot water and/or space heating within a building. The system may be used in the method, characterized in that the system comprises a1 st storage device comprising a1 st phase change material, a1 st detector for determining a charge state of the 1 st storage device, and a1 st phase change material heat exchanger adapted to exchange heat between refrigerant from a refrigeration circuit and the 1 st phase change material. The system further includes a 2 nd storage device containing a 2 nd phase change material, a 2 nd detector for determining a charge state of the 2 nd storage device, and a 2 nd phase change material heat exchanger adapted to exchange heat between the 2 nd phase change material and water of a thermal medium circuit. A controller is configured to control operation of the system based at least on the charge state of the 1 st storage device and the charge state of the 2 nd storage device. Background The main limitation of heat pump heating products for single-family homes is the low heat transfer rate (typically 5-15 kW) compared to small complex boilers (typically 20-30 kW). This means that the heat pump must often be fitted with a tank for domestic hot water, which can be charged for a longer time when convenient. At a supply temperature of about 42 ℃, a typical shower uses about 7 litres of water per minute, assuming a tap water temperature of 10 ℃, which results in a thermal load of about 16kW. A single shower uses about 50 litres of water and 6.5MJ (1.8 kWh) of heat. Phase change materials have been proposed as a more compact alternative to traditional water-based thermal storage for domestic heating applications, i.e. space heating and domestic hot water heating. These two applications have different temperature requirements. For Domestic Hot Water (DHW), the point of use temperature is typically in the range of 40-55 ℃, while for space heating the temperature range may be higher or lower, depending on the type of heating system and the dimensioning basis of the heating system. Older central heating systems using fossil fuel boilers and conventional radiator designs may use water flow temperatures in the range of 60-80 ℃, while modern heating systems designed for electric heat pumps use large radiator areas with water flow temperatures in the range of 35-45 ℃. Meanwhile, heat pumps are designed to operate throughout the year under various outdoor conditions. A typical mode for heat pump control in space heating operation is to use a climate compensation profile for which the water flow temperature increases with decreasing outdoor ambient temperature. This means that the air source heat pump needs to operate under a wide range of "temperature rise" conditions, where "temperature rise" is the difference between the heat source temperature and the output temperature of the heat pump in heating mode. Thus, when designed for use in winter higher peak load conditions, air source heat pumps can suffer from partial load inefficiency when the heat source temperature (outdoor air temperature) is very low and the required heat transfer temperature (water flow temperature) is very high. In other words, the coefficient of performance (COP) of these heat pump systems is low. A configuration for improving the efficiency and coefficient of performance of a heat pump is proposed which divides the pump heating process into two phases, each with a small temperature rise, and uses the surface as a heat reservoir to store the thermal energy pumped from the air (e.g. at <0 ℃) at an intermediate temperature (e.g. at 10 ℃) until it is required, at which point the thermal energy can be pumped through the 2 nd phase to its required delivery temperature (e.g. 40 ℃ for space heating). The problem with this approach is that the cost of installing shallow coil or deep well surface heat exchangers tends to be high and inconvenient, which makes the method and system very expensive. For demand side flexibility services, more attention is paid to increasing the heat storage available for both domestic hot water and space heating. In this regard, many heat pump systems are designed with a heat accumulator that can be used to compensate for heat pump run time from space heating demand time. A problem with this approach is that the space requirements for both the domestic hot water storage tank and the space heating regenerator (typically a water storage tank) inside the building may be excessive for many individual houses. JP2008180473a discloses a system and method in which, when the heat source is insufficient or does not meet the demand of the user side, the heat pump is operated by night electricity using the atmosphere as the heat source to provide backup heat supply. JP2012007796a discloses a system and method in which a heat storage system inclu