KR-20260065624-A - Air source heat pump and method for defrosting an air source heat pump

KR20260065624AKR 20260065624 AKR20260065624 AKR 20260065624AKR-20260065624-A

Abstract

A method for defrosting an air heat exchanger of an air source heat pump is provided, the method comprising: receiving refrigerant from the air heat exchanger into a refrigerant storage unit of the heat pump; passing refrigerant from the refrigerant storage unit through an expansion valve to expand the refrigerant before it passes through a refrigerant heat exchanger in liquid refrigerant within the storage unit; supplying refrigerant from the refrigerant heat exchanger to a heat exchanger of a heating system; supplying refrigerant from the heat exchanger of the heating system to a compressor of the heat pump and then supplying refrigerant from the compressor to an air heat exchanger; and controlling the expansion valve to control the amount of energy extracted through the refrigerant heat exchanger from the heat exchanger of the heating system and from the refrigerant within the storage unit. A corresponding heat pump device is also provided.

Inventors

캐슬스, 제이슨

Assignees

옥토퍼스 에너지 히팅 리미티드

Dates

Publication Date: 20260508
Application Date: 20240827
Priority Date: 20230913

Claims (20)

A method for defrosting an air heat exchanger of an air source heat pump, A step of receiving refrigerant from an air heat exchanger into the refrigerant storage unit of a heat pump; A step of passing the refrigerant through an expansion valve from the refrigerant storage unit to expand the refrigerant before the refrigerant passes through a refrigerant heat exchanger in the liquid refrigerant within the storage unit; A step of supplying refrigerant from the above refrigerant heat exchanger to the heat exchanger of the heating system; and A method for defrosting an air heat exchanger, comprising the step of supplying refrigerant from the heat exchanger of the heating system to the compressor of the heat pump, and then supplying refrigerant from the compressor to the air heat exchanger.
In Article 1, An air heat exchanger defrosting method further comprising the step of controlling the expansion valve to control the amount of energy extracted from the heat exchanger of the heating system and from the refrigerant in the storage unit through the refrigerant heat exchanger.
In Article 1 or Article 2, A method for defrosting an air heat exchanger, further comprising the step of determining the need to defrost the air heat exchanger based on a detected change in the electrical characteristics or electrical behavior of the motor of the fan of the heat pump.
In Paragraph 3, An air heat exchanger defrosting method in which the detected change in the above electrical characteristics is an increase in the current or power drawn by the motor.
In Paragraph 3, An air heat exchanger defrosting method in which the detected change in the above electrical characteristics is an increase in the effective duty cycle of the pulse width modulation drive to the motor.
In any one of paragraphs 1 to 5, A method for defrosting an air heat exchanger, further comprising the step of determining successful defrosting of the air heat exchanger based on a detected change in the electrical characteristics of the fan motor of the heat pump.
In Article 6, A method for defrosting an air heat exchanger, wherein the successful defrosting of the air heat exchanger is detected based on the detected reduction of the current drawn by the motor of the fan of the heat pump.
In Article 6, A method for defrosting an air heat exchanger, wherein the successful defrosting of the air heat exchanger is detected based on the detected reduction of the effective duty cycle of the pulse width modulation drive for the motor of the fan of the heat pump.
In any one of paragraphs 3 through 8, A method for defrosting an air heat exchanger, further comprising the step of storing one or more reference values for current or power drawn by the motor, and/or optionally (optionally) one or more reference values for a pulse width modulation duty cycle for the motor obtained during the installation of the heat pump.
An air source heat pump comprising a fluid storage unit (312) for holding a liquid refrigerant, wherein the fluid storage unit (312) comprises a heat exchanger (301) that is at least partially submerged in the liquid refrigerant when in use, and an expansion valve (344) is provided to a refrigerant flow path that is the input side of the heat exchanger (301) in a cooling mode of operation.
In Article 10, Air heat exchanger (320); Heating system heat exchanger (334); Compressor (332); and It further includes a refrigerant storage unit (312) for liquid refrigerant; The heat pump has a defrosting mode in which refrigerant is supplied from the compressor (332) to the air heat exchanger (320), then to the refrigerant storage unit (312), and then to the heating system heat exchanger (334) before returning to the compressor (332); the heat pump further comprises a refrigerant heat exchanger (301) and an expansion valve (344), wherein the refrigerant heat exchanger (301) is located within the refrigerant storage unit (312); In the above defrosting mode, the expansion valve (344) supplies refrigerant from the storage unit (312) to the refrigerant heat exchanger (301), and the arrangement causes the refrigerant to first be expanded by passing through the expansion valve (344) and then pass through the heat exchanger in the liquid refrigerant within the refrigerant storage unit (312) before being supplied to the heating system heat exchanger (334), an air heat source heat pump.
In Article 10, The heat pump comprises a compressor (332) for compressing a refrigerant, an air heat exchanger (320) for extracting energy from ambient air during a heating mode of operation, and a storage unit (312) for liquid refrigerant that allows the refrigerant to flow from an input unit (315, 355) into which the refrigerant is received from the air heat exchanger (320) to an output unit (353, 357), and then through an expansion valve (344) to a refrigerant heat exchanger (301) and then through a heating system heat exchanger (334) to the compressor (332), wherein, in use, the refrigerant heat exchanger (301) is at least partially submerged in the liquid refrigerant within the storage unit (312), thus forming an air source heat pump.
In any one of paragraphs 10 to 12, An air source heat pump further comprising a processor programmed to determine the need to defrost the air heat exchanger based on a detected change in the electrical characteristics or electrical behavior of the motor of the fan (324) of the heat pump.
In Article 13, An air source heat pump, wherein the above electrical characteristic is an increase in driving current or an increase in the rate of change of driving current.
In Article 13, The above electrical characteristic is an increase in the effective duty cycle of the pulse width modulation drive for the motor, an air heat source heat pump.
In any one of paragraphs 13 to 15, The above processor is further programmed to determine the successful defrosting of the air heat exchanger based on a detected change in the electrical characteristics or electrical behavior of the motor of the fan of the heat pump, an air heat source heat pump.
In Article 16, The above electrical characteristic used to determine successful defrosting is a reduction in driving current or a reduction in the rate of change of driving current, for an air source heat pump.
In Article 17, The electrical characteristic used to determine successful defrosting is a reduction in the effective duty cycle of the pulse width modulation drive for the motor, in an air heat source heat pump.
In any one of paragraphs 14 through 18, The above processor is programmed to determine and store the current drawn by the motor of the fan and/or the duty cycle of the pulse width modulation motor drive when the heat pump is commissioned, for an air heat source heat pump.
In any one of Articles 10 through 19, An air source heat pump further comprising a processor operatively connected to a camera and/or another optical sensor to detect ice build-up on the air heat exchanger matrix.

Description

Air source heat pump and method for defrosting an air source heat pump The present invention relates to an air source heat pump and a method for defrosting an air source heat pump. According to Directive 2012/27/EU, buildings account for 40% of final energy consumption and 36% of CO2 emissions. The EU Commission’s 2016 report, "Mapping and Analysis of Heating/Cooling Fuel Deployment (Fossil/Renewable Energy) Now and in the Future (2020-2030)," concluded that heating and hot water alone account for 79% (192.5 Mtoe) of total final energy use in EU households. The EU Commission also reported, based on 2019 Eurostat figures, that approximately 75% of heating and cooling is still generated from fossil fuels, while only 22% is generated from renewable energy. To achieve the EU’s climate and energy goals, the heating and cooling sector must drastically reduce energy consumption and decrease the use of fossil fuels. Heat pumps, which utilize energy drawn from air, land, or water, have been identified as potentially significant contributors to addressing this issue. Since only a fraction of households have access to a body of water to support the use of heat pumps that extract energy from water, and the cost and space requirements for installing ground source heat exchangers are also substantial, it is generally cheaper and more convenient to install air source heat pumps. Furthermore, it is generally recognized that air source heat pumps are a better replacement for conventional central gas heating boilers. However, air source heat pumps have one disadvantage not shared by heat pumps that extract energy from bodies of water or the ground: when the heat pump is operated to extract energy from ambient air ("heating mode"), the heat pump's air heat exchanger must be defrosted periodically in mild and cooler climates. An air heat exchanger is a heat exchanger in which heat from ambient air is transferred to a liquid refrigerant in heating mode. Typically, a matrix of finned tubes (more commonly conduits) contains the cold liquid refrigerant, and ambient air is moved over the tubes by the action of a fan or impeller. In heating mode, energy is extracted from the ambient air because the liquid refrigerant is colder than the ambient air; as the temperature rises, the liquid refrigerant vaporizes, and the temperature of the ambient air decreases. Consequently, water vapor carried by the ambient air tends to condense on the surface of the air heat exchanger. If the ambient air temperature is sufficiently low, water condensing on the surface of the air heat exchanger will freeze to form ice. This ice buildup reduces the heat transfer efficiency of the air heat exchanger, and significant ice accumulation can block gaps between adjacent conduits, causing a loss of airflow and consequently a further reduction in efficiency. Consequently, air source heat pumps are configured to occasionally perform what is known as a defrost cycle (which actually involves temporarily running the heat pump in a cooling mode where heat is given up from the refrigerant to the surroundings through the air heat exchanger), during which relatively warm refrigerant is fed into the air heat exchanger to melt the ice and thus restore the efficiency of the air heat exchanger. The frequency of defrost cycle events is every 35 minutes, possibly for 10 minutes at a time, but depends on ambient conditions and, among other things, the amount of heat load the system intends to transfer. Therefore, the defrosting cycle entails the reverse of the general energy extraction cycle used in heating mode: the heat pump operates in reverse, and energy is transferred from the home (e.g., from a heated space within the home, or from hot water in a space heating system or a domestic hot water supply) to the air heat exchanger and thus to the surroundings. The present invention seeks to provide an air source heat pump in which at least some of the disadvantages of existing air source heat pumps are wholly or partially mitigated. According to a first embodiment, a method for defrosting an air heat exchanger of an air source heat pump is provided, and the method comprises: A step of supplying refrigerant from the compressor of a heat pump to an air heat exchanger; A step of receiving refrigerant from an air heat exchanger within a refrigerant storage unit; The method includes the step of passing refrigerant from a refrigerant storage unit through an expansion valve to expand the refrigerant before passing the expanded refrigerant through a refrigerant heat exchanger within the storage unit, supplying the refrigerant from the refrigerant heat exchanger to a heat exchanger of a heating system, and returning the refrigerant from the heat exchanger of the heating system to a compressor. According to a second embodiment, a method for defrosting an air heat exchanger of an air source heat pump is provided, and the method comprises: A step of supplying refrigerant from the compresso