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DK181869B1 - Method for defrosting an air heat pump and heat pump comprising a defrosting system - Google Patents

Method for defrosting an air heat pump and heat pump comprising a defrosting system Download PDF

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Publication number
DK181869B1
DK181869B1 DKPA202330106A DKPA202330106A DK181869B1 DK 181869 B1 DK181869 B1 DK 181869B1 DK PA202330106 A DKPA202330106 A DK PA202330106A DK PA202330106 A DKPA202330106 A DK PA202330106A DK 181869 B1 DK181869 B1 DK 181869B1
Authority
DK
Denmark
Prior art keywords
temperature
defrosting
heat pump
pause
tpause
Prior art date
Application number
DKPA202330106A
Other languages
Danish (da)
Inventor
Gardø Christensen Kim
Lund Rasmussen Jonas
Andersen Henrik
Alvandifar Negar
Original Assignee
Fenagy As
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fenagy As filed Critical Fenagy As
Priority to DKPA202330106A priority Critical patent/DK181869B1/en
Priority to EP24185243.3A priority patent/EP4484858A1/en
Priority to US18/757,791 priority patent/US20250003658A1/en
Priority to CA3244781A priority patent/CA3244781A1/en
Application granted granted Critical
Publication of DK181869B1 publication Critical patent/DK181869B1/en
Publication of DK202330106A1 publication Critical patent/DK202330106A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B13/00—Compression machines, plants or systems, with reversible cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/30—Control or safety arrangements for purposes related to the operation of the system, e.g. for safety or monitoring
    • F24F11/41—Defrosting; Preventing freezing
    • F24F11/42—Defrosting; Preventing freezing of outdoor units
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B30/00—Heat pumps
    • F25B30/02—Heat pumps of the compression type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B47/00—Arrangements for preventing or removing deposits or corrosion, not provided for in another subclass
    • F25B47/02—Defrosting cycles
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B47/00—Arrangements for preventing or removing deposits or corrosion, not provided for in another subclass
    • F25B47/02—Defrosting cycles
    • F25B47/022—Defrosting cycles hot gas defrosting
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B47/00—Arrangements for preventing or removing deposits or corrosion, not provided for in another subclass
    • F25B47/02—Defrosting cycles
    • F25B47/022—Defrosting cycles hot gas defrosting
    • F25B47/025—Defrosting cycles hot gas defrosting by reversing the cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B5/00—Compression machines, plants or systems, with several evaporator circuits, e.g. for varying refrigerating capacity
    • F25B5/02—Compression machines, plants or systems, with several evaporator circuits, e.g. for varying refrigerating capacity arranged in parallel
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
    • F25D21/00—Defrosting; Preventing frosting; Removing condensed or defrost water
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
    • F25D21/00—Defrosting; Preventing frosting; Removing condensed or defrost water
    • F25D21/002—Defroster control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2339/00—Details of evaporators; Details of condensers
    • F25B2339/04—Details of condensers
    • F25B2339/047—Water-cooled condensers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2347/00—Details for preventing or removing deposits or corrosion
    • F25B2347/02—Details of defrosting cycles
    • F25B2347/021—Alternate defrosting
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/02—Humidity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/19—Pressures
    • F25B2700/197—Pressures of the evaporator
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/21—Temperatures
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/21—Temperatures
    • F25B2700/2106—Temperatures of fresh outdoor air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/21—Temperatures
    • F25B2700/2117—Temperatures of an evaporator
    • F25B2700/21171—Temperatures of an evaporator of the fluid cooled by the evaporator
    • F25B2700/21172—Temperatures of an evaporator of the fluid cooled by the evaporator at the inlet
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/21—Temperatures
    • F25B2700/2117—Temperatures of an evaporator
    • F25B2700/21171—Temperatures of an evaporator of the fluid cooled by the evaporator
    • F25B2700/21173—Temperatures of an evaporator of the fluid cooled by the evaporator at the outlet
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/21—Temperatures
    • F25B2700/2117—Temperatures of an evaporator
    • F25B2700/21175—Temperatures of an evaporator of the refrigerant at the outlet of the evaporator

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Air Conditioning Control Device (AREA)

Abstract

Method for defrosting an air source heat pump (2) comprising a plurality of outdoor evaporators (6, 6’, 6’’, 6’’’) each comprising a number of coils (20, 20’, 20’’, 20’’’) each comprising fins (8, 8’, 8’’, 8’’’) and pipes (30, 30’, 30’’, 30’’’). The heat pump (2) comprises a defrost system that applies a defrosting medium to provide thermal energy to defrost the coils (20, 20’, 20’’, 20’’’). The method comprising: a) by using at least one temperature sensor (12) measuring at least one temperature (T₁, T₂, T₃) of at least one of the coils (20, 20’, 20’’, 20’’’) of at least one of the outdoor evaporators (6, 6’, 6’’, 6’’’); b) activating the defrost system and hereby performing several defrost processes each having a duration (T defrost) separated by a pause (T pause) without defrosting, when the at least one temperature (T₁, T₂, T₃) is below a predefined temperature value, d) by using at least one temperature sensor (16, 16’, 16’’) measuring at least one outdoor temperature (T out ₁, T out ₂, T out ₃), The method comprises the following steps: determine a maximum allowable pause time (T pause, ₘₐₓ) in dependency of the at least one outdoor temperature (T out ₁, T out ₂, T out ₃).

Description

DK 181869 B1 1
Method for Defrosting a Heat Pump and Heat Pump Comprising a
Defrost System
Field of invention
The present invention relates to a method for defrosting an air source heat pump comprising a plurality of outdoor evaporators each comprising a number of coils each comprising fins and pipes. The present invention also relates to an air source heat pump comprising a plurality of outdoor evaporators each comprising a number of coils, said heat pump comprising a defrost system that applies a defrosting medium to provide thermal energy to defrost the coils.
Prior art
Different defrost control strategies have been used in the air source heat pumps with the time control method being the most common one. These control strategies include time control, pressure difference control, and temperature control.
Defrosting is an energy demanding process. Accordingly, one would like to wait as long as possible to initiate defrosting process. The performance, however, decreases as the frost is created and moreover, it is difficult to defrost if one waits too long time.
EP0278701A2 discloses an adaptive heat exchanger defrost system e.g. for a heat pump evaporator, incorporates a system controller which adapts the intervals between defrost cycles to prevailing conditions in order to improve overall efficiency. The time taken to complete a defrost cycle is measured and compared with the time taken for the preceding defrost cycle to determine whether it is appropriate to increase or decrease the interval between samplings of the operating parameter used to determine whether a defrost cycle is required. The defrost cycle is in practice, however, not adapted in a manner sufficient to provide improve overall efficiency in a sufficient manner. Accordingly, it would be
DK 181869 B1 2 advantageous to provide an alternative to this solution.
The prior art methods for controlling defrost of heat pumps detect a fin temperature and applies it for determining when to start and stop the defrost procedure. These systems are, however, based on a single or two control methods. Accordingly, the prior art solutions have a poor performance.
Thus, there is a need for a method and an air source heat pump which enables a higher performance, and which reduces or even eliminates the above mentioned disadvantages of the prior art.
Summary of the invention
The object of the present invention can be achieved by a method as defined in claim 1 and by an air source heat pump as defined in claim 10.
Preferred embodiments are defined in the dependent subclaims, explained in the following description and illustrated in the accompanying drawings.
The method according to the invention is a method for defrosting an air source heat pump comprising a plurality of outdoor evaporators each comprising a number of fans and a number of coils each comprising fins and pipes, wherein the heat pump comprises a defrost system that applies a defrosting medium to provide thermal energy to defrost the coils, the method comprising: a) by using at least one coil temperature sensor measuring at least one coil temperature of at least one of the coils of at least one of the outdoor evaporators; b) activating the defrost system and hereby performing several defrost processes each having a duration (Tidefrost) Separated by a pause (Tpause) Without defrosting, when the at least one temperature is below a predefined temperature value,
DK 181869 B1 3 c) by using at least one temperature sensor measuring at least one outdoor ambient temperature (Tout 1, Tout 2, Tout 3), wherein the method comprises the following steps: determine a maximum allowable pause time (T pause, max) in dependency of the at least one outdoor ambient temperature (Tout 1, Tout 2, Tout 3).
Hereby, it is possible to provide a method that enables a higher performance, and which reduces or even eliminates the above mentioned disadvantages of the prior art.
The method according to the invention is a method for defrosting an air source heat pump. The heat pump comprises a plurality of outdoor evaporators each comprising a number of fans and a number of coils each comprising fins and pipes.
The heat pump comprises a defrost system that applies a defrosting medium to provide thermal energy to defrost the coils.
The method comprising: a) by using at least one temperature sensor measuring at least one temperature of at least one of the coils of at least one of the outdoor evaporators; b) activating the defrost system and hereby performing several defrost processes each having a duration (Teefrost) Separated by a pause (Tpause) Without defrosting, when the at least one temperature is below a predefined temperature value, c) by using at least one temperature sensor measuring at least one outdoor temperature (Tout 1, Tout 2, Tout 3).
The method comprises the following steps: determine a maximum allowable pause time (T pause, max) in dependency of the at least one outdoor temperature (Tout 1, Tout 2, Tout 3).
DK 181869 B1 4
By determining a maximum allowable pause time (Tpause, max) in dependency of the at least one outdoor temperature (Tout 1, Tout 2, Tout 3), it is possible to provide an adaptive method that automatically adapts to the the at least one outdoor temperature (Tout 1, Tout2, Tout 3).
The term “determine” in the expression: “determine a maximum allowable pause time (Tpause, max) in dependency of the at least one outdoor temperature (Tout 1, Tout2, Tout 3)” may by way of example refer to: 1) a calculation by using one or more predefined formulas or; 2) application of a lookup table comprising predefined values; 3) application of a predefined algorithm.
In an embodiment, the maximum allowable pause time (Tpause, max) is in the range 10-300 min.
In an embodiment, the maximum allowable pause time (Tpause, max) is in the range 60-200 min.
In an embodiment, the maximum allowable pause time (Tpause, max) is in the range 100-150 min.
In an embodiment, the temperature is a surface temperature.
In an embodiment, the predefined temperature value is OC.
In an embodiment, the predefined temperature value is 0.5°C.
In an embodiment, the predefined temperature value is 0.9°C.
In an embodiment, the defrosting medium is water containing glycol.
DK 181869 B1
In an embodiment, the defrosting medium is a high temperature refrigerant.
In an embodiment, the defrosting medium is a medium temperature 5 refrigerant.
In an embodiment, the at least one temperature sensor is arranged to detect a temperature at a surface of at least one of the coils.
In an embodiment, at least one temperature is an average temperature calculated on the basis of two or more temperatures detected by at least two temperature sensors.
The pause (Tpause) Without defrosting is the elapsed time since the end of the last defrosting process for evaporator in question.
In an embodiment, the method comprising: - by using at least one sensor detecting a pressure difference (AP) across an evaporator and - activating the defrost system when the pressure difference (AP) across the evaporator is above a predefined pressure difference level (APmax).
Hereby, it is possible to apply the pressure difference (AP) across the evaporator to activate the defrost system.
In an embodiment, the method comprising: - by using at least one humidity sensor detecting the relative humidity (H) of the ambient air, wherein the method comprising: - activating the defrost system in dependency of the relative humidity (H).
DK 181869 B1 6
In an embodiment, the method comprising: - determining a minimum allowable pause time (Tpause min safety), - ensuring that the defrost system is only activated when the pause (Tpause) has exceeded the minimum allowable pause time (Tpause min safety).
In an embodiment, the method comprising: - determining a maximum allowable pause time (Tpause max safety), - determining the time/pause (Tpause) since the last defrost process and - activating the defrost system when the pause (Tpause) has exceeded the maximum allowable pause time (Tpause, max).
In an embodiment, the method comprising: - detecting a temperature of the defrosting medium, wherein the duration (Tietrost) Of a defrost process is determined in dependency of: a) the at least one outdoor temperature (Tout 1, Tout 2, Tout 3) and b) the temperature of the defrosting medium.
In an embodiment, the method defrosts all evaporators sequentially one at a time.
In an embodiment, no break is provided in between.
In an embodiment, the method defrosts a fraction of the evaporators sequentially one at a time. Hereby, the remaining fraction of the evaporators can be operated.
In an embodiment, no break is provided in between.
In an embodiment, a pause is provided between the defrost of the last evaporator and the next process (the subsequent defrost of the first
DK 181869 B1 7 evaporator).
In an embodiment, no pause is provided between the defrost of the last evaporator and the next process (the subsequent defrost of the first evaporator).
In an embodiment, the predefined pressure difference level (APmax) corresponds to 20-50 % blockage ratio.
In an embodiment, the “blockage ratio” is defined as the ratio between the frost thickness and half of the fin spacing (the distance between adjacent fins).
In an embodiment, the predefined pressure difference level (APmax) corresponds to 30-45 % blockage ratio.
In an embodiment, the predefined pressure difference level (APmax) corresponds to 40 % blockage ratio.
In an embodiment, the defrosting medium is recircled water-containing liquid.
In an embodiment, the defrosting medium comprises glycol.
In an embodiment, the defrosting medium is cooled refrigerant.
In an embodiment, the defrosting medium is heated refrigerant.
In an embodiment, the the heat pump comprises an air inlet and an air outlet, wherein the method comprises detecting a temperature of the air inlet and a temperature of the air outlet, wherein: a) when the difference the temperature of the air inlet and temperature of the air outlet during a defrost process exceeds a predefined level,
DK 181869 B1 8 operation of the fans of the heat pump is initiated and maintained for a predefined time period.
This is done to keep the heat in the casing by running the fans upwards for a user defined period. When the time period has exceeded a new measurement of one of the sensors is needed to start the period.
In an embodiment, the method comprising: = determining a maximum allowable pause time T pause, max safety, - ensuring that the defrost system is activated when the pause (Tpause) has exceeded the maximum allowable pause time Tpause, max safety.
In an embodiment, the maximum allowable pause time Tpause, max safety IS set by the user, wherein the maximum allowable pause time Tpause, max safety IS overruling the determined Tpause, max.
In an embodiment, the Tpause max savety iS in the range 15-600 min.
In an embodiment, the Tpause max savety iS in the range 90-400 min.
In an embodiment, the Tpause max savety is in the range 200-600 min.
Tpause max savety May depend on the number of evaporators og the given system.
In an embodiment, the method comprising: - defining a minimum allowable pause time Tpause, min safety, - ensuring that the defrost system is not activated when before the pause (Tpause) has exceeded the required minimum allowable pause time T pause, min safety.
In an embodiment, the Tpause min safety is in the range 10-100 min.
DK 181869 B1 9
In an embodiment, the Tpause min safety is in the range 10-75 min.
In an embodiment, the Tpause min safety is in the range 10-25 min.
Tpause min savety May depend on the number of evaporators og the given system.
The heat pump according to the invention is an air source heat pump comprising a plurality of outdoor evaporators each comprising a number of fans and a number of coils, said heat pump comprising a defrost system that applies a defrosting medium to provide thermal energy to defrost the coils, wherein the heat pump comprises at least one coil temperature sensor arranged and configured to measure at least one coil temperature (Ty, T2, T3) of at least one of the coils of at least one of the outdoor evaporators, wherein the defrost system is configured to perform several defrost processes each having a duration (Tdefrost) Separated by a pause (Tpause) without defrosting when the at least one temperature (Ti, T2, T3) is below a predefined temperature value, the defrost system comprising: - at least one temperature sensor arranged and configured to measure at least one outdoor ambient temperature (Tout 1, Tout 2,
Tout 3), wherein the defrost system is configured to: - determining a maximum allowable pause time (Tpause, max) in dependency of: a) the at least one outdoor ambient temperature (Tout 1, Tout 2, Tout 3).
Hereby, it is possible to provide a provide a heat pump that enables a higher performance, and which reduces or even eliminates the above mentioned disadvantages of the prior art.
DK 181869 B1 10
The heat pump is an air source heat pump comprising a plurality of outdoor evaporators. Each outdoor evaporator comprises a number of coils.
The heat pump comprises a defrost system that applies a defrosting medium to provide thermal energy to defrost the coils.
The heat pump comprises at least one temperature sensor arranged and configured to measure at least one temperature (Ti, T2, T3) of at least one of the coils of at least one of the outdoor evaporators.
In an embodiment, an average temperature is calculated on the basis of temperature measurements made by several temperature sensors.
The defrost system is configured to perform several defrost processes each having a duration (Tuefrost) Separated by a pause (Tpause) without defrosting when the at least one temperature (Ti, Tz, T3) is below a predefined temperature value.
The defrost system comprises: - at least one temperature sensor arranged and configured to measure at least one ambient (outdoor) temperature (Tout 1, Tout 2,
Tout 3).
The defrost system is configured to: - determine a maximum allowable pause time (Tpause, max) in dependency of: a) the at least one ambient (outdoor) temperature (Tout1, Tout2, Tout 3).
The term “determine” may by way of example refer to: 1) a calculation by using one or more predefined formulas or; 2) application of a lookup table comprising predefined values;
DK 181869 B1 11 3) application of a predefined algorithm.
By determining a maximum allowable pause time (Tpause, max) in dependency of the at least one outdoor temperature (Tout 1, Tout 2, Tout 3), it is possible to provide an adaptive defrost system i that automatically adapts to the the at least one outdoor temperature (Tout 1, Tout2, Tout 3).
In an embodiment, the defrost system comprises: - at least one sensor arranged and configured to detect a pressure difference (AP) across an evaporator, wherein the defrost system is configured to activating the defrost system when the pressure difference (AP) across the evaporator is above a predefined pressure difference level (APmax).
Hereby, the defrost system can take into consideration the pressure difference (AP) across the evaporator.
In an embodiment, the defrost system comprises: - at least one humidity sensor arranged and configured to detect the relative humidity (H) of the ambient air, wherein the defrost system is configured to: - determine a maximum allowable pause time (Tpause, max) in dependency of the relative humidity (H).
Hereby, the defrost system can take into consideration the relative humidity (H) of the ambient air.
The term “determine” may by way of example refer to: 1) a calculation by using one or more predefined formulas or; 2) application of a lookup table comprising predefined values; 3) application of a predefined algorithm.
DK 181869 B1 12
In an embodiment, the air source heat pump is configured to ensure that the defrost system is only activated when the pause (Tpause) has exceeded the minimum allowable pause time (Tpause min safety).
Hereby, it is possible ensure that pause (Tpause) is not less than the minimum allowable pause time (Tpause, min).
In an embodiment, the air source heat pump is configured to: - determine the time since the last defrost process and - activate the defrost system when the pause (Tpause) has exceeded a predefined maximum allowable pause time (Tpause, max).
In an embodiment, the air source heat pump is configured to: - detect a temperature of the defrosting medium, wherein the duration (Taefrost) Of a defrost process is determined in dependency of: a) the at least one outdoor ambient temperature (Tout 1, Tout 2, Tout 3) and b) the temperature of the defrosting medium.
In an embodiment, the air source heat pump is configured to defrost a fraction of the evaporators at a time only.
In an embodiment, the air source heat pump is configured to defrost all evaporators sequentially one at a time. In an embodiment, no break is provided in between.
In an embodiment, the air source heat pump is configured to defrost a fraction of the evaporators sequentially one at a time.
In an embodiment, a pause is provided between the defrost of the last evaporator and the next process (the subsequent defrost of the first evaporator).
DK 181869 B1 13
In an embodiment, no pause is provided between the defrost of the last evaporator and the next process (the subsequent defrost of the first evaporator).
In an embodiment, the predefined pressure difference level (APmax) corresponds to 20-50 % blockage ratio.
In an embodiment, the heat pump comprises an air inlet and an air outlet, wherein the heat pump is configured to detect a temperature of the air inlet and a temperature of the air outlet, wherein the heat pump is configured to ensure that: a) when the difference between the temperature of the air inlet and temperature of the air outlet during a defrost process exceeds a predefined level, operation of the fans is initiated and maintained for a predefined time period.
In an embodiment, the least one temperature sensor is arranged and configured to measure at least one surface temperature of at least one of the coils of at least one of the outdoor evaporators.
In an embodiment, the predefined pressure difference level (APmax) corresponds to 35-40 % blockage ratio.
In an embodiment, the at least one temperature sensor is arranged to detect a temperature at a surface of at least one of the coils.
In an embodiment, the at least one temperature is an average temperature calculated on the basis of two or more temperatures detected by at least two temperature sensors.
Description of the Drawings
The invention will become more fully understood from the detailed description given herein below. The accompanying drawings are given by way of illustration only, and thus, they are not limitative of the present
DK 181869 B1 14 invention. In the accompanying drawings:
Fig. 1 shows a schematic view of a heat pump according to the invention;
Fig. 2 shows a flowchart of a method according to the invention;
Fig. 3A shows a schematic cross-sectional view of the fins of coil of a heat pump according to the invention;
Fig. 3B shows another schematic cross-sectional view of the fins of the coil shown in Fig. 3A;
Fig. 4 shows a table illustrating the defrosting processes of a method according to the invention;
Fig. 5 shows a heat pump according to the invention comprising an indoor unit installed in a building and
Fig. 6 shows a flowchart of a method according to the invention.
Detailed description of the invention
Referring now in detail to the drawings for the purpose of illustrating preferred embodiments of the present invention, a heat pump 2 of the present invention is illustrated in Fig. 1.
Fig. 1 illustrates a schematic view of a heat pump 2 according to the invention. The heat pump 2 comprises an indoor unit 29 comprising compressors or a pump depending on the application (not shown). The indoor unit 29 is connected to several outdoor coils 20, 20’, 20”, 20” by using forward lines 48’, 50’ and return lines 48, 50. The dotted lines are used in the defrost circuit. The solid lines are used in the refrigerant circuit.
Each of the outdoor coils 20, 20’, 20”, 20'” comprises: - an evaporator 6, 6’, 6”, 6"; - afan 42; - a pipe 30, 30', 30”, 30”” for conducting the refrigerant through the
DK 181869 B1 15 coil 20, 20’, 20”, 20'” and - apipe 31, 31’, 31”, 31" for conducting a defrosting medium through the coil 20, 20’, 20”, 20".
The refrigerant flows from the indoor unit 29 to the forward lines 50’ to the first coil 20 through a first refrigerant pipe 30, to the second coil 20’ through a second refrigerant pipe 30’, to the third coil 20 through a third refrigerant pipe 30” and to the fourth coil 20” through a fourth refrigerant pipe 30".
The refrigerant is returned to the indoor unit 29 from the coils 20, 20’, 20”, 20" through the return line 50.
The indoor unit 29 supplies a defrosting medium to the outdoor coils 20, 20', 20”, 20'” by using a forward line 48 that is connected toto the first coil 20 through a first defrosting pipe 31, to the second coil 20' through a second defrosting pipe 31’, to the third coil 20 through a third defrosting pipe 31” and to the fourth coil 20" through a fourth defrosting pipe 317”.
The defrosting medium is returned to the indoor unit 29 from the coils 20, 207, 20”, 20" through the return line 48.
In an embodiment, the indoor unit 29 supplies hot water to a plate heat exchanger (not shown) via a supply water line 36. The the indoor unit 29 receives water from the heat exchanger via a return water line 38.
A differential pressure sensor 14 is arranged and configured to detect the pressure difference AP across the first evaporator 6. Hereby, the differential pressure sensor 14 is configured to detect when the pressure difference AP across the first evaporator 6 is above a predefined pressure difference level APmax.
DK 181869 B1 16
A first temperature sensor 16 is arranged to detect an ambient (outdoor) temperature Tout 1. The ambient (outdoor) temperature Tout 1 is typically measured at the air-side inlet of the first evaporator 6. In an embodiment, additional outdoor temperatures are detected. In an embodiment, the ambient temperature Tout 1 is the temperature of the inlet (an inlet temperature). The temperature sensors applied for measuring the ambient (outdoor) temperature Tout 1 or other ambient temperatures are typically arranged outside the coils 20, 20', 20”, 20".
In an embodiment, a first ambient (outdoor) temperature Tout 1 iS measured at an air-side inlet of the first evaporator 6 by using a first temperature sensor 16, wherein a second ambient (outdoor) temperature
Tout 2 is measured at an air-side inlet of the first evaporator 6 by using a second temperature sensor 16”.
In an embodiment, a first ambient (outdoor) temperature Tout 1 is measured outside the first evaporator 6 by using a first temperature sensor 16, wherein a second ambient (outdoor) temperature Tout2 is measured outside the first evaporator 6 by using a second temperature sensor 16', wherein a third ambient (outdoor) temperature Tout 3 is measured outside one of the remaining evaporators (e.g. the second evaporator 67) by using a third temperature sensor 16”. In general, the ambient (outdoor) temperatures may be measured by using temperature sensors arranged outside, typically at or in close proximity to an air-side inlet.
In an embodiment, an outlet temperature Toutiet is measured at the outlet of the first evaporator 6 by using a temperature sensor 46.
In an embodiment, a temperature of the liquid in the return water line 38 is measured by using a temperature sensor 32.
DK 181869 B1 17
In an embodiment, a temperature of the fins of the first evaporator 6 is measured by using a temperature sensor 12.
In an embodiment, heat pump 2 comprises a humidity sensor 40 arranged and configured for detecting the relative humidity of the ambient air. In an embodiment, the humidity sensor 40 is outside one of the coils 20, 20’, 20”, 207”. In an embodiment, the humidity sensor 40 is at the air-side inlet of an evaporator. In general, the relative humidity of the ambient air may be measured by using one or more humidity sensors arranged outside, typically at or in close proximity to an air-side inlet.
In an embodiment, heat pump 2 comprises a control unit 10 arranged and configured for carrying out the method according to the invention. In an embodiment, the control unit 10 arranged and configured for receiving data from the sensors of the heat pump 2. The data may be transmitted to the control unit 10 via wires or via wireless connections. In an embodiment, the control unit 10 is electrically connected to the indoor unit 29. The indoor unit 29 is connected to an energy source (e.g. the mains) which is not shown in Fig. 1.
Fig. 2 illustrates a flowchart of a method according to the invention. The first step is to start the heat pump 2.
In the next step it is evaluated if the temperature of the fins Trin is below a predefined temperature level. In an embodiment, the predefined temperature level is 0°C.
If the temperature of the fins Tr, is above the predefined temperature level (e.g. 0°C), no defrosting is initiated.
If the temperature of the fins Trin is below the predefined temperature level (e.g. OC), it is evaluated if: a) the pressure difference AP across the first evaporator 6 is above a
DK 181869 B1 18 predefined pressure difference level APmax Or b) the pause Tpause has exceeded the maximum allowable pause time
T pause, max.»
If either of these two conditions a), b) is meet, the defrosting is initiated and the defrosting is maintained for a time period Tdefrost.
In an embodiment, it is ensured that the time period Tiefrost exceeds a predefined minimum defrosting time period Tiaefrost, min. When the time period Tdefrost exceeds the predefined minimum defrosting time period
Tdefrost, min, the defrosting of the evaporator can be stopped as long as the fin temperature is above the predefined threshold. If Tdefrost exceeds Taefrost max safety, the defrost process is stopped.
In an embodiment, the minimum defrosting time period Tdefrost, min IS determined (e.g. calculated) on the basis of at least one detected air temperature and/or a return temperature of the defrosting media.
In an embodiment, the maximum allowable pause time Tpause, max iS determined (e.g. calculated) on the basis of at least one detected air temperature and/or a relative humidity measurement of ambient air.
Even though it is not shown, the fin temperature is detected after "start defrosting”. Moreover, when the time exceeds the Taefrost,min, the fin temperate will be checked and if the fin temperature is above a predefined threshold, or the Tdefrost exceeds Tdefrost max safety, the defrost process will be stopped.
Fig. 3A illustrates a schematic cross-sectional view of the fins 8, 8’, 8”, 8'” of coil 20 of a heat pump according to the invention. An air flow 24 enters the air gap 22 between adjacent fins 8, 8’, 8”, 8”. Since the fin temperature is above OC, no ice is present on the fins 8, 8’, 8”, 8".
DK 181869 B1 19
Accordingly, the distance between adjacent fins (fin spacing) D: is maximum and thus the pressure difference (AP) across the evaporator of the coil 20 is low and not above a predefined pressure difference level
APmax.
Fig. 3B illustrates another schematic cross-sectional view of the fins 8, 8', 8”, 87” of the coil 20 shown in Fig. 3A. The fin temperature is below
OC and the fins 8, 8’, 8”, 8” are covered by a layer of ice 26. Accordingly, the distance between adjacent fins (fin spacing) Di is lower than in Fig. 3A. Accordingly, the pressure difference (AP) across the evaporator of the coil 20 has increased.
Fig. 4 illustrates a table illustrating the defrosting processes of a method according to the invention. No pause is provided between the defrost of each evaporator and the next process (the subsequent defrost of the first evaporator).
At time to, defrost of evaporator 1 is initiated. At time t; evaporator 1 has been defrosted.
At time ti, defrost of evaporator 2 is initiated. At time t; evaporator 2 has been defrosted.
At time t;, defrost of evaporator 3 is initiated. At time ts evaporator 3 has been defrosted.
At time t:, defrost of evaporator 4 is initiated. At time t4 evaporator 4 has been defrosted.
A pause is provided between time ts and ts.
At time ts, defrost of evaporator 1 is initiated. At time ts evaporator 1 has
DK 181869 B1 20 been defrosted.
At time ts, defrost of evaporator 2 is initiated. At time t; evaporator 2 has been defrosted.
At time ty, defrost of evaporator 3 is initiated. At time ts evaporator 3 has been defrosted.
At time ts, defrost of evaporator 4 is initiated. At time ts evaporator 4 has been defrosted. A break is conducted from time ts to tio.
Fig. 5 illustrates a heat pump 2 according to the invention comprising an indoor unit 29 installed in a building 44. The heat pump 2 comprises an outdoor coil 20, in which a fan 42 is arranged and configured to suck an air flow 24 into the coil 20 through air gaps between adjacent fins 8
Fig. 5 illustrates an air to air heat pump 2. A heat exchanger 120 is arranged and configured to heat water inside the building 44. In an embodiment the water is used for district heating. The heat exchanger 120 is arranged and configured to heat the room in which the heat exchanger 120 is placed.
The heat pump 2 comprises an indoor unit 29 arranged and configured to receive a refrigerant through a return line 52 that connects the outlet of the outdoor coil 20 to the indoor unit 29. The indoor unit 29 provides pressurised refrigerant to the outdoor coil 20 via the forward line 54.
The indoor unit 29 is in fluid communication with the heat exchanger 120 via the forward line 56 and via the return line 58.
The heat pump 2 comprises a defrosting circuit that delivers a defrosting medium from the indoor unit 29 to the outdoor coil 20 through the forward defrosting line 62. The defrosting medium is returned to the
DK 181869 B1 21 indoor unit 29 via the return defrosting line 64. In an embodiment, the defrosting medium is refrigerant received by the compressor via the forward line 56.
Fig. 6 illustrates a flowchart of a method according to the invention. The first step is to start the heat pump.
In the next step it is evaluated if Tpause (the elapsed time since the end of the last defrosting process for evaporator in question) has exceeded a predefined level, Tpause min safety. If Tpause has not yet exceeded the predefined level Tpause min safety, @ waiting step is conducted until Tpause exceeds the predefined level, so the following condition is meet: 1) Tpause > T pause min safety.
In the next steps it is evaluated if: a) the pressure difference AP across the evaporator is above a predefined pressure difference level APmax and b) If Tpause (the elapsed time since the end of the last defrosting process for evaporator in question) has exceeded a determined maximum allowable time Tpause, max.
If either condition a) or condition b) is meet, it is evaluated if the coil temperature exceeds a predefined threshold 1. If the coil temperature exceeds the predefined threshold 1, the defrost process is initiated. If not, the previous steps (after Start) are repeated.
If the pressure difference AP across the evaporator is not above the predefined pressure difference level APmax and if Tpause (the elapsed time since the end of the last defrosting process for evaporator in question) has not exceeded a predefined maximum allowable level Tpause, max, it is evaluated if the pressure difference AP exceeds the predefined pressure difference level APmax and if Tpause has exceeded a the predefined
DK 181869 B1 22 maximum allowable level Tpause, max.
During the defrost process the defrost time Taefrost is initially set to zero and the defrost process continues until the defrost time Tiefrost exceeds a predefined minimum requires defrost time level, Tdefrost, min.
In the next step is evaluated if: c) the defrost time Tidefrost has exceeded a predefined maximum allowable defrost time T defrost max safety and d) the coil temperature has exceeded the predefined threshold 2.
If either of the conditions c) or d) are meet, the defrost process (of evaporation 1) is stopped.
If the defrost time T4errost has not exceeded the predefined maximum allowable defrost time Taefrost, max the defrost process continues.
Similarly, if the coil temperature has not yet exceeded the predefined threshold 2 the defrost process continues.
When the defrost process of evaporator 1 has ended the defrost process of evaporator 2 is initiated. This process continues until all evaporators have been defrosted.
In an embodiment, the threshold 1 is 0.5°C or 0°C.
DK 181869 B1 23
List of reference numerals 2 Heat pump 6,6’, 6”, 6" Evaporator 8, 87, 8” 8” Fin
Control unit 12 Temperature sensor 14 Pressure differential sensor 10 16 Temperature sensor 20, 20', 20”, 20” — Coil 22 Air gap 24 Air flow 26 Ice 28 Compressor 29 Indoor unit 30, 30’, 30”, 30”” Pipe
AP Pressure difference
Tout 1, Tout 2, Tout 3 Ambient temperature
Toutlet Outlet temperature
T1, T2, T3 Temperature
T pause Pause (duration)
T pause, max Maximum allowable pause time
APmin Predefined pressure difference level
T defrost Duration
H Relative humidity of the ambient air
S3 Air inlet
S4 Air outlet
Di, D2 Distance between adjacent fins (fin spacing) 32 Temperature sensor 36 Supply water line 38 Return water line
DK 181869 B1 24 40 Humidity sensor 42 Fan 44 Building 46 Temperature sensor 48 Forward line 48’ Return line 50 Forward line 50° Return line 52 Return line 54 Forward line 56 Forward line 58 Return line 60 Valve 62 Defrosting line 64 Defrosting line 120 Heat exchanger

Claims (17)

DK 181869 B1 25 PatentkravDK 181869 B1 25 Patent claims 1. Fremgangsmåde til afrimning af en luftvarmepumpe (2), og som omfatter en flerhed af udendarsfordampere (8, 6,67, 67), der hver omfatter et antal ventilatorer (42) og et antal spiralrer (20, 20°, 20", 20™), der hvert omfafter finner (8, 8, 8”, 87) og rør (30, 30', 307, 30), hvor varmepumpen (2) omfatter et afrimningssystem, der anvender et alrimningsmiddel til at tilvejebringe termisk energi til afrimning af spiralrørene (20, 20°, 20", 20), hvilken fremgangsmåde omfatter a} ved hjælp af mindst én spiralrerstemperatursensor (12) måling af mindst en spiralrorstemperatur (11, Tz, Ta) for mindst ét af spiralrørene (20, 20°, 20", 20") i mindst én af udendørsfordampeme (6, 6, 67, 67); b) aktivering af afrimningssystemet og derved udførelse af flere afrimningsprocesser, der hver har en varighed (Tætost) adskilt af en pause {Tpause} Uden afrimning, når den mindst ene spiralfrørstemperatur (Ti, Tz, Ta} er under en foruddefineret temperaturværdi, c) ved hjælp af mindst én temperatursensor (16, 168°, 167) måling af mindst én omgivende udendørstemperatur (Tout 1, Toute, Touts), kendetegnet ved, at fremgangsmåden omfatter følgende trin: at bestemme en maksimalt tilladt pausetid (Tpause, max) afhængigt af den mindst ene omgivende udendørstemperatur {Tout 1, Fout2, Touts).1. A method for defrosting an air source heat pump (2), comprising a plurality of outdoor evaporators (8, 6, 67, 67), each comprising a number of fans (42) and a number of coils (20, 20°, 20", 20™), each comprising fins (8, 8, 8", 87) and tubes (30, 30', 307, 30), the heat pump (2) comprising a defrosting system using a de-icing agent to provide thermal energy for defrosting the coil tubes (20, 20°, 20", 20), the method comprising a} measuring at least one coil tube temperature (11, Tz, Ta) for at least one of the coil tubes (20, 20°, 20", 20") in at least one of the outdoor evaporators (6, 6, 67, 67); b) activating the defrosting system and thereby performing several defrosting processes, each having a duration (Tdest) separated by a pause {Tpause} Without defrosting when the at least one coil temperature (Ti, Tz, Ta} is below a predefined temperature value, c) by means of at least one temperature sensor (16, 168°, 167) measuring at least one ambient outdoor temperature (Tout 1, Toute, Touts), characterized in that the method comprises the following steps: determining a maximum permissible pause time (Tpause, max) depending on the at least one ambient outdoor temperature {Tout 1, Fout2, Touts). 2. Fremgangsmåde ifølge krav 1, hvor fremgangsmåden omfatter - ved hjælp af mindst én sensor (14, 14', 147) detektering af en tryklorske! (AP) over en fordamper (6, 6, 6", 6) og - aktivering af afrimningssystemet, når tykforskellen {AP} over fordamperen (8, 6, 67, 6) er over et foruddefineret tryklorskelsniveau (APmax).2. Method according to claim 1, wherein the method comprises - by means of at least one sensor (14, 14', 147) detecting a pressure threshold (AP) across an evaporator (6, 6, 6", 6) and - activating the defrosting system when the thickness difference {AP} across the evaporator (8, 6, 67, 6) is above a predefined pressure threshold level (APmax). DK 181869 B1 26DK 181869 B1 26 3. Fremgangsmåde ifølge krav 1 eller 2, hvor fremgangsmåden omfatter - ved hjælp af mindst én fugtmåler detektering af den omgivende lufts relative fugtighed (H), hvor fremgangsmåden omfatter - bestemmelse af en maksimalt tilladt pausetid (Tpause, max) afhængigt af den relative fugtighed (H)3. Method according to claim 1 or 2, wherein the method comprises - by means of at least one humidity meter detecting the relative humidity (H) of the ambient air, wherein the method comprises - determining a maximum permitted pause time (Tpause, max) depending on the relative humidity (H) 4. Fremgangsmåde ifølge et hvilket som helst af de foregående krav, hvor fremgangsmåden omfatter - definering af en minimalt tilladt pausetid (Tpause, min safety), - — sikring af, at afrimningssystemet kun aktiveres, når pausen (Tpause) har overskredet den minimalt tilladte pausetid (T pause, min safety).4. Method according to any one of the preceding claims, wherein the method comprises - defining a minimum allowed pause time (Tpause, min safety), - - ensuring that the defrosting system is only activated when the pause (Tpause) has exceeded the minimum allowed pause time (T pause, min safety). 5. Fremgangsmåde ifølge et hvilket som helst af de foregående krav, hvor fremgangsmåden omfatter - bestemmelse af en maksimalt tilladt pausetid (T pause, max), - bestemmelse af tiden/pausen (Tpause) siden den seneste afrimningsproces og - — aktivering af afrimningssystemet, når pausen (Tpause) har overskredet den maksimalt tilladte pausetid (Tpause, max).5. Method according to any one of the preceding claims, wherein the method comprises - determining a maximum allowed pause time (T pause, max), - determining the time/pause (T pause) since the last defrost process and - - activating the defrost system when the pause (T pause) has exceeded the maximum allowed pause time (T pause, max). 6. Fremgangsmåde ifølge et hvilket som helst af de foregående krav, hvor fremgangsmåden omfatter - —2detektering af en temperatur på afrimningsmidlet, hvor varigheden (Taetrost) af en afrimningsproces bestemmes afhængigt af: a) den mindst ene udendørstemperatur (Tout 1, Tout2, Tout3) Og b) temperaturen pa afrimningsmidlet.6. Method according to any one of the preceding claims, wherein the method comprises - —2detecting a temperature of the defrosting agent, wherein the duration (Taetrost) of a defrosting process is determined depending on: a) the at least one outdoor temperature (Tout 1, Tout2, Tout3) and b) the temperature of the defrosting agent. 7. Fremgangsmåde ifølge et hvilket som helst af de foregående krav, hvor fremgangsmåden omfatter afrimning af kun en fraktion af fordamperne (6, 6', 6”, 6”) ad gangen.A method according to any one of the preceding claims, wherein the method comprises defrosting only one fraction of the evaporators (6, 6', 6", 6") at a time. DK 181869 B1 27DK 181869 B1 27 8. Fremgangsmåde ifølge et hvilket som helst af de foregående krav, hvor det foruddefinerede trykforskelsniveau (APmax) svarer til 20-50 % af blokeringsforholdet.8. A method according to any one of the preceding claims, wherein the predefined pressure difference level (ΔPmax) corresponds to 20-50% of the blocking ratio. 9. Fremgangsmåde ifølge et hvilket som helst af de foregående krav, hvor varmepumpen (2) omfatter en luftindgang (S3) og en luftudgang (S4), hvor fremgangsmåden omfatter detektering af en temperatur på luftindgangen (S3) og en temperatur på luftudgangen (S4), hvor: a) når forskellen mellem luftindgangens (S3) temperatur og luftudgangens (S4) temperatur under en afrimningsproces overstiger et foruddefineret niveau, driften af ventilatorerne startes og opretholdes i et foruddefineret tidsrum.9. Method according to any one of the preceding claims, wherein the heat pump (2) comprises an air inlet (S3) and an air outlet (S4), wherein the method comprises detecting a temperature of the air inlet (S3) and a temperature of the air outlet (S4), wherein: a) when the difference between the temperature of the air inlet (S3) and the temperature of the air outlet (S4) during a defrosting process exceeds a predefined level, the operation of the fans is started and maintained for a predefined period of time. 10. Luftkildevarmepumpe (2), der omfatter en flerhed af udendørsfordampere (6, 6°, 6”, 6°”), der hver omfatter et antal ventilatorer (42) og et antal spiralrør (20, 20°, 20”, 20”), hvilken varmepumpe (2) omfatter et afrimningssystem, der anvender et afrimningsmiddel til at tilvejebringe termisk energi til afrimning af spiralrørene (20, 20°, 20”, 20’), hvor varmepumpen (2) omfatter mindst én spiralrørstemperatursensor (12) indrettet og konfigureret til at måle mindst én spiralrørstemperatur (T1, T2, T3) for mindst ét af spiralrørene (20, 20°, 20”, 20”) i mindst én af udendørsfordamperne (6, 6’, 6”, 6”), hvor afrimningssystemet er konfigureret foretage flere afrimningsprocesser, der hver har en varighed (Taetrost) adskilt af en pause (Tpause) uden afrimning, når den ene spiralrørstemperatur (T1, T2, Ta) er under en foruddefineret temperaturværdi, hvilket afrimningssystem omfatter: - mindst én temperatursensor (16, 16', 16”) anbragt og konfigureret til at måle mindst én omgivende udendørstemperatur (Tout 1, Tout 2, Tout 3),10. An air source heat pump (2) comprising a plurality of outdoor evaporators (6, 6°, 6”, 6°”), each comprising a number of fans (42) and a number of coil tubes (20, 20°, 20”, 20”), the heat pump (2) comprising a defrosting system using a defrosting agent to provide thermal energy for defrosting the coil tubes (20, 20°, 20”, 20’), the heat pump (2) comprising at least one coil tube temperature sensor (12) arranged and configured to measure at least one coil tube temperature (T1, T2, T3) for at least one of the coil tubes (20, 20°, 20”, 20”) in at least one of the outdoor evaporators (6, 6’, 6”, 6”), the defrosting system being configured to perform multiple defrosting processes, each having a duration (Taetrost) separated by a pause (Tpause) without defrosting when the one coil temperature (T1, T2, Ta) is below a predefined temperature value, the defrosting system comprising: - at least one temperature sensor (16, 16', 16”) arranged and configured to measure at least one ambient outdoor temperature (Tout 1, Tout 2, Tout 3), DK 181869 B1 28 kendetegnet ved, at afrimningssystemet er konfigureret til at: - bestemme en maksimalt tilladt pausetid (Tpause, max) afhængigt af: a) den mindst ene omgivende udendørstemperatur (Tout 1, Tout 2, ToutDK 181869 B1 28 characterized in that the defrosting system is configured to: - determine a maximum allowed pause time (Tpause, max) depending on: a) the at least one ambient outdoor temperature (Tout 1, Tout 2, Tout 3).3). 11. Luftkildevarmepumpe (2) ifølge krav 10, hvor afrimningssystemet omfatter: - mindst én sensor (14, 14’, 14”) indrettet og konfigureret til at detektere en trykforskel (AP) over en fordamper (6, 6’, 6”, 6), hvor afrimningssystemet er konfigureret til at aktivere afrimningssystemet (4), når trykforskellen (AP) over fordamperen (6, 6', 6”, 6) er over et foruddefineret trykforskelsniveau (APmax).11. Air source heat pump (2) according to claim 10, wherein the defrosting system comprises: - at least one sensor (14, 14', 14") arranged and configured to detect a pressure difference (AP) across an evaporator (6, 6', 6", 6), wherein the defrosting system is configured to activate the defrosting system (4) when the pressure difference (AP) across the evaporator (6, 6', 6", 6) is above a predefined pressure difference level (APmax). 12. Luftkildevarmepumpe (2) ifølge krav 10 eller 11, hvor afrimningssystemet (4) omfatter: - mindst én fugtmåler indrettet og konfigureret til at detektere den omgivende lufts relative fugtighed (H), hvor afrimningssystemet er konfigureret til at: - bestemme en maksimalt tilladt pausetid (Tpause, max) afhængigt af den relative fugtighed (H).12. Air source heat pump (2) according to claim 10 or 11, wherein the defrosting system (4) comprises: - at least one moisture meter arranged and configured to detect the relative humidity (H) of the ambient air, wherein the defrosting system is configured to: - determine a maximum permitted pause time (Tpause, max) depending on the relative humidity (H). 13. Luftkildevarmepumpe (2) ifølge krav 10-12, hvor luftkildevarmepumpen (2) er konfigureret til at sikre, at afrimningssystemet kun aktiveres, når pausen (Tpause) har overskredet den minimalt tilladte pausetid (T pause, min safety).13. Air source heat pump (2) according to claims 10-12, wherein the air source heat pump (2) is configured to ensure that the defrosting system is only activated when the pause (Tpause) has exceeded the minimum allowed pause time (T pause, min safety). 14. Luftkildevarmepumpe (2) ifølge krav 10-13, hvor luftkildevarmepumpen (2) er konfigureret til at: - bestemme tiden/pausen (Tpause) Siden den seneste afrimningsproces og - — aktivere afrimningssystemet, når pausen (Tpause) har overskredet en foruddefineret maksimalt tilladt pausetid (Tpause, max).14. Air source heat pump (2) according to claims 10-13, wherein the air source heat pump (2) is configured to: - determine the time/pause (Tpause) since the last defrost process and - - activate the defrost system when the pause (Tpause) has exceeded a predefined maximum allowed pause time (Tpause, max). DK 181869 B1 29DK 181869 B1 29 15. Luftkildevarmepumpe (2) ifølge krav 10-14, hvor luftkildevarmepumpen (2) er konfigureret til at: - — detektere en temperatur pa afrimningsmidlet, hvor varigheden (Taetrost) af en afrimningsproces bestemmes afhængigt af: a) den mindst ene omgivende udendørstemperatur (Tout 1, Tout2, Tout3) og b) temperaturen pa afrimningsmidlet.15. Air source heat pump (2) according to claims 10-14, wherein the air source heat pump (2) is configured to: - — detect a temperature of the defrosting agent, wherein the duration (Taetrost) of a defrosting process is determined depending on: a) the at least one ambient outdoor temperature (Tout 1, Tout2, Tout3) and b) the temperature of the defrosting agent. 16. Luftkildevarmepumpe (2) ifølge krav 10-15, hvor varmepumpen (2) omfatter en luftindgang (S3) og en luftudgang (S4), hvor varmepumpen (2) er konfigureret til at detektere en temperatur for luftindgang (S3) og en temperatur for luftudgangen (S4), hvor varmepumpen (2) er konfigureret til at sikre: a) når forskellen mellem luftindgangens (S3) temperatur og luftudgangens (S4) temperatur under en afrimningsproces overstiger et foruddefineret niveau, at drift af ventilatorerne startes og opretholdes i et foruddefineret tidsrum.16. Air source heat pump (2) according to claims 10-15, wherein the heat pump (2) comprises an air inlet (S3) and an air outlet (S4), wherein the heat pump (2) is configured to detect a temperature of the air inlet (S3) and a temperature of the air outlet (S4), wherein the heat pump (2) is configured to ensure: a) when the difference between the temperature of the air inlet (S3) and the temperature of the air outlet (S4) during a defrosting process exceeds a predefined level, that operation of the fans is started and maintained for a predefined period of time. 17. Luftkildevarmepumpe (2) ifølge krav 10-15, hvor den mindst ene temperatursensor (12) er indrettet til at detektere en temperatur ved en flade af mindst ét af spiralrørene (20, 20', 20”, 20”).17. Air source heat pump (2) according to claims 10-15, wherein the at least one temperature sensor (12) is arranged to detect a temperature at a surface of at least one of the spiral tubes (20, 20', 20”, 20”).
DKPA202330106A 2023-06-28 2023-06-28 Method for defrosting an air heat pump and heat pump comprising a defrosting system DK181869B1 (en)

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DKPA202330106A DK181869B1 (en) 2023-06-28 2023-06-28 Method for defrosting an air heat pump and heat pump comprising a defrosting system
EP24185243.3A EP4484858A1 (en) 2023-06-28 2024-06-28 Method for defrosting a heat pump and heat pump comprising a defrost system
US18/757,791 US20250003658A1 (en) 2023-06-28 2024-06-28 Methods for Defrosting a Heat Pump and Heat Pumps Comprising a Defrost System
CA3244781A CA3244781A1 (en) 2023-06-28 2024-06-28 Method for Defrosting a Heat Pump and Heat Pump Comprising a Defrost System

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