FR2595797A1 - METHOD FOR QUICKLY ESTABLISHING THE PERMANENT REGIME OF OPERATION OF AN AIR CONDITIONING APPARATUS, THIS APPARATUS AND METHOD FOR DEFROSTING A HEAT PUMP - Google Patents

Abstract

THE INVENTION RELATES TO A METHOD AND A DEVICE FOR QUICKLY ESTABLISHING THE PERMANENT OPERATING REGIME OF AN AIR CONDITIONING INSTALLATION, FOR EXAMPLE A HEAT PUMP INSTALLATION. IT CONSISTS OF USING A DOUBLE DRAIN REGULATOR ASSEMBLY 12 WHICH ESTABLISHES A FREE FLOW PATH, IN A DUCT 40, OF THE REFRIGERANT FLUID, FROM THE LOW PRESSURE PART TO THE HIGH PRESSURE PART OF THE INSTALLATION 10, TO RELEASE THE REFRIGERANT FROM THE LOW PRESSURE PART TO THE HIGH PRESSURE PART, AND TO ESTABLISH A PATH OPPOSING A RESISTANCE TO THE FLOW, BY MEANS OF ELEMENTS 42, 44, TO DOSE THE FLOW OF THE REFRIGERANT FLUID FROM THE HIGH PART PRESSURE TO LOW PRESSURE PART. FIELD OF APPLICATION: AIR CONDITIONING SYSTEMS.

Description

The invention relates generally

  the field of refrigeration, and more particularly devices and methods for initiating the cycle of operation of a refrigeration apparatus to minimize cyclic losses due to non-steady state operation.

  Increasing energy costs have increased the demand for efficient heating and cooling systems of all types and sizes. Heat pumps have become popular quickly, largely because of the efficiency of heat pumps compared to that of conventional heating systems. The efficiencies of the heat pumps themselves have also been improved. 15 mainly by improving the yields of the

  compressors, fans and motors used in heat pumps. Newly designed heat pumps use larger coils to improve seasonal performance by increasing steady state efficiency.

  In the steady-state operation of an air-conditioning installation, about 65-80% of the refrigerant charge is on the high-pressure side of the installation. During prolonged shutdown periods, a large portion of the coolant migrates to the evaporator because the latter is generally at a lower ambient pressure than the condenser. At the beginning of the next operating cycle, the excess refrigerant charge in the bottom side of the plant must be pumped to the high sides for the steady state to be established. The coolant in the evaporator flows to the accumulator, the suction pressure drops to a low enough value to vaporize the liquid, and the compressor pumps the steam to the condenser. This process can take several minutes during which the air conditioning installation does not operate at its steady state capacity. Cyclic losses are greater in installations with larger coils due to the greater amount of refrigerant charge from these facilities. In a conventional heat pump, the period during which the coolant is pumped from the evaporator to the condenser to achieve steady state operation can be 6 minutes or more. A similar problem occurs during a defrost cycle of a heat pump, both at the beginning of the defrost cycle and at its end, and when resuming operation in heating mode. When the cycle is reversed, at the beginning and at the end of a defrosting cycle, the coolant flows to the accumulator and gradually exits by boiling to establish the steady state of operation. Therefore, the heating efficiency of the heat pump is reduced by the disadvantages resulting from an improper refrigerant position when the functions of the heat exchanger are reversed, at the beginning of the defrost cycle and at the restart. Operation in heating mode. The time required for defrosting is lengthened due to the cyclic loss occurring at the beginning of a defrost cycle, and the amount of additional heat required is increased due to the two cyclic losses. The isolation of each coil by means of electrovalve substantially reduces the migration of the refrigerant during the rest cycle, due to temperature differences. Although the normal cyclic losses due to the migration of the coolant can thus be reduced, no reduction in cyclic losses occurring in the defrosting cycle resulting from the reversal of the functions of the heat exchanger is achieved. and the poor positioning resulting from the coolant. In addition, because of the high differential pressure at which the compressor is subjected to start-up, a difficult starting kit must be incorporated in such an installation. Cost reductions resulting from a reduction in cyclical losses generally do not justify additional equipment.

  when the coils are isolated by solenoid valves.

  One of the main objects of the present invention is therefore to provide an air conditioning installation and a method for operating the installation, making it possible to rapidly reach a steady state of operation so as to substantially reduce the losses. cyclical effects due to

non-permanent regime.

  The subject of the invention is also a

  An air conditioning installation and a method for operating this installation, eliminating the need for an accumulator and offsetting the refrigerant migration without requiring the presence of difficult start kits.

  Another object of the invention is a method for operating an air conditioner, which substantially reduces the cyclic losses in a heat pump, which losses result from non-steady state operation.

  as a result of improper positioning of the coolant, due to a reversal of the functions of the heat exchanger, both at the beginning of a defrosting cycle and at resuming operation in normal heating mode.

  These objects as well as other objects are made according to the invention by a dual flow expander assembly mounted in the coolant line between the heat exchangers of a conventional air conditioning apparatus. An inversion valve is provided in the compressor discharge line, and at the beginning of a cycle the reversing valve is set to a position directing the refrigerant flow in the opposite direction to that of the desired mode. Operating. The regulator assembly

  Double flow is opened in order to oppose practically no resistance to flow in the refrigerant line between the heat exchangers.

  The coolant is flown from the future evaporator to the future condenser, and the dual flow expansion valve assembly is closed in a dosing state. The inversion valve is set to direct the coolant in the direction appropriate for the desired operating mode, and normal operation begins. In a heat pump, at the beginning of a defrost cycle, the dual flow expander assembly is opened to allow refrigerant to flow from the inner coil to the outer coil. The inverter valve is then passed to defrost mode, the dual flow expander assembly is set to a metering state of the refrigerant and defrosting results. At the end of the defrost cycle, the dual flow expander assembly is reopened to oppose substantially no flow resistance in the fluid line.

  In the case of the refrigerant, the coolant flows to the inner coil, the reversing valve is set to the heating operation mode, and the dual flow expander assembly is closed in a metering state of the coolant.

  The invention will be described in more detail with reference to the accompanying drawing by way of non-limiting example and in which the single figure is a diagram of a heat pump having a dual flow expander assembly for operating in accordance with the method of the invention. 'invention.

  Referring more particularly to the drawing, reference numeral 10 denotes a heat pump of substantially conventional design but having a dual flow expander assembly 12 which allows

  at the heat pump to operate according to the method of the invention. The dual flow regulator assembly replaces the regulators and check valves generally found in the coolant line between the heat exchangers of a pump.

  heat. The operation of the dual flow expansion valve assembly will be described more fully hereinafter. The heat pump also comprises a compressor 14, an indoor heat exchanger 16 and an outdoor heat exchanger 18. A storage tank 20

  is provided in the pipe 21 for closing the compressor; however, it is contemplated that an air conditioner can be operated in accordance with the method of the invention without the need for an accumulator.

  The indoor heat exchanger 16 includes a coolant heat exchange coil 22 to the air and a fan 24, and it also includes, as shown, a heating coil 30 with electrical resistance 26 of reinforcement. The outdoor heat exchanger 18 includes a refrigerant heat exchange coil 28 to the air and a fan 30. Inner and outer heat exchangers are of conventional design and will not be described in more detail. An inversion valve 32 is

  connected to the discharge port of the compressor via a refrigerant pipe 34, to the suction port of the compressor via a suction pipe 21 and to the coils 22 and 28 via the water supply pipes 36 and 38. refrigerant, respectively.

  The inversion valve is also of conventional design for directing the refrigerant vapor under high pressure from the compressor to the inner coil in heating operation mode, or to the outer coil in cooling operation mode,

  or for defrosting, and for returning the cooling fluid of the evaporator coil to the compressor.

  A refrigerant pipe 40 is disposed between the inner coil 22 and the outer coil 28, and the above-mentioned dual flow expander assembly 12 is mounted in this conduit 40. Although the dual flow expander assembly may include many different types 20-valve structures whose functions cooperate, or a single complex valve that can be traversed without resistance by a flow and allowing a dosed flow in one direction or the other, the assembly is shown schematically as comprising dosing passages 42 and 44 for dosing the refrigerant flowing therethrough following paths directed, respectively, to the inner coil 22 and to the outer coil 28. A solenoid valve 46 or the like is mounted in line 40, and this valve 46 can to be open 30 in order to be traversed without resistance by the fluid

  refrigerant flowing in the pipe 40, or it can be closed to allow the refrigerant fluid to flow only through the dosing orifice 42 or the dosing orifice 44, these orifices being connected to the pipe 40 through lines 48 and 50 of

  bypassing the direct passage through the entire

containing the solenoid valve 46.

  Since the fundamental structure of a heat pump according to the invention has been fully described, the operation of the heat pump in each of its modes will now be more fully described.

  heat according to the method of the invention.

  At the beginning of a cooling mode cycle, the coolant has migrated to the inner coil 22 due to lower ambient temperatures in the interior assembly. For steady state operation, about 65 to 80 percent of the coolant should be in the high pressure side including the outer coil 28. To quickly establish this condition at the beginning of the operating cycle, the dual flow expansion valve assembly 12 is set in a free-flow state in which the valve 46 is open and the flow of the refrigerant is limited only by the capacity of the conundrum 40. The inversion valve 32 is set to the position of operation in the heating mode in which the refrigerant vapor, under high pressure, is directed to the inner coil 22. The compressor is started and the excess refrigerant present in the inner coil is rapidly discharged through the expander assembly double flow to the outdoor coil. When the coolant has been discharged from the inner coil, which may take a few seconds, the dual flow expansion valve assembly 12 is set to a metering state in which the free flow passage through the valve 46 is closed. The inversion valve 32 is set to the appropriate position for cooling mode operation in which the refrigerant vapor is directed to the coil

  outside. A typical operation in cooling mode then follows.

  During operation in the heating mode, a process is followed which is the reverse of that just described for operation in the cooling mode.

  The excess coolant has migrated to the outer coil which is at a lower ambient temperature than the inner coil. At the beginning of a heating cycle, the reversing valve 32 is set to an operating position in the cooling mode, the double flow expander assembly 12 is set to a free flow state in which the valve 46 is completely open, and the compressor is turned on to flush the coolant from the outer coil to the inner coil. Once this is done, the dual flow regulator assembly is set to a refrigerant dosing state in which the valve 46 is closed, the inversion valve is set for operation in the heating mode and it follows. a classic heating cycle. As before, the refrigerant was conveniently positioned in the heat pump in a few seconds, eliminating the non-steady operation for many minutes which is often found in

conventional installations.

  When a defrost cycle is requested, the inversion valve is initially in an operating position in the heating mode and the compressor is normally running. With the inverting valve remaining in the operating position in the heating mode, the dual flow expander assembly is set to a free flow state in which the valve 46 is fully open, the compressor continues to operate, and the refrigerant from the inner coil is pumped rapidly to the outer coil. The dual flow regulator assembly is then set to a metering state of the coolant, the inverting valve 32 is set to an operating position in cooling mode for defrosting and the defrost cycle follows. At the end of the defrost cycle, the inverting valve 32 is left in the operating position in the cooling or defrosting mode, the dual flow regulator 12 is set to a free-flow position and the coolant is quickly pumped from the outside serpen10 tin to the inner coil. All

  The dual flow regulator is set to a fluid dosing position, and the reversing valve is set to an operating position in the heating mode to complete the cycle.

  Significant energy savings can.

  result of the implementation of the method of the invention, in particular during the operating mode in defrosting, because it eliminates many minutes of operation in non-steady state, both at the beginning of a defrost cycle and at the resumption of the heating mode cycle. The defrost cycle is performed more efficiently, reducing the time required for defrosting and the required backup heat. The fundamental cycles of cooling and heating are more efficiently achieved by decreasing cyclic losses, which shortens the cycle time-out intervals.

  and decreases energy consumption.

  The invention is also quite suitable for an air conditioning installation working only in cooling. In such an installation, an inversion valve and a dual flow expander assembly must be added to the circuit. At the beginning of each cooling cycle, the plant 35 operates as previously described for the cycle of cooling.

  cooling a heat pump.

  It is also planned to be able to use the dual flow regulator assembly to limit the degree of overheating at the outlet of the evaporator. A semiconductor regulator can be used to optimize overheating according to the conditions

  existing operating conditions as well as to control the installation at the beginning of the operating cycles.

  Therefore, in addition to improving the overall efficiency of the plant by minimizing non-steady state operation times, the invention can also be used to improve steady state operation.

  permanent and further increase the efficiency of an air conditioning installation.

  It goes without saying that many modifications can be made to the air conditioning installation and to its method of implementation described and shown, in particular with reference to a heat pump.

  heat, without departing from the scope of the invention.

Claims (12)

  A method for rapidly establishing the steady state of operation of an air conditioner comprising a compressor (14), a condenser (16 or 18) and an evaporator (16 or 18), the process being characterized in that it comprises, at start-up, the steps of establishing a substantially free path for the flow of refrigerant from the evaporator to the condenser, flowing the refrigerant from the evaporator to the condenser through the free flow path, and to establish a pathway opposing flow resistance for metering condenser refrigerant flow to the evaporator.   2. Method according to claim 1, characterized in that the step of flowing the refrigerant is to operate the compressor and to direct the compressed refrigerant vapor   from this compressor to the evaporator.   3. Method according to claim 1, characterized in that it further comprises establishing a substantially free flow path for the refrigerant fluid from the condenser to the evaporator, to flow the refrigerant from the condenser to the evaporator, 25 to establish a flow resistance path for dosing refrigerant flow from the evaporator to the condenser, operating the compressor, and directing the compressed refrigerant vapor from the compressor to the evaporator to defrost it. last, and to repeat the steps of establishing a substantially free flow path for the refrigerant fluid from the evaporator to the condenser, flowing the coolant from the evaporator to the condenser, and establishing an opposing path Resistance to the flow of refrigerant   to assay the latter from the condenser to the evaporator.   4. A process according to claim 3, characterized in that the steps of flowing the refrigerant is to operate the compressor and to direct the refrigerant vapor from the compressor to the condenser or evaporator thereof. flows the refrigerant.   A method for operating an air conditioner comprising a compressor (14), an evaporator (16 or 18), a condenser (16 or 18), fluid lines (34, 36, 38, 40) refrigerant arranged between the compressor and the condenser, between the evaporator and the compressor and between the evaporator and the condenser, a first valve means (12) disposed in the coolant line between the evaporator and the condenser and comprising an open flow passage portion (46) in an operating state in which the refrigerant fluid can flow through said valve means, substantially without the latter, placed between the evaporator and the condenser, opposes a resistance to this flow, the valve means also having a dosing portion (42, 44) which opposes flow resistance when the valve means is placed in a position in which the refrigerant flow It is arranged between the condenser and the evaporator, an inverting valve (32) having first and second working positions for directing the refrigerant vapor from the compressor to the condenser or the evaporator, the process being characterized in that it consists of placing the first valve means in the free flow position, adjusting the reversing valve to direct the refrigerant vapor from the compressor to the evaporator, to operate the compressor so that it pumps the excess refrigerant liquid from the evaporator   to the condenser through the free flow portion of the first valve means, placing the first valve means in the position opposing flow resistance to meter the flow of coolant from the condenser to the evaporator , and adjust the reversing valve to direct refrigerant vapor from the compressor to the condenser.   6. Method according to claim 5, characterized in that it further consists of placing the first valve means in the free flow position while maintaining the inversion valve in a position such that the refrigerant vapor is pumped to the condenser, to pump the excess refrigerant liquid from the condenser to the evaporator, to place the first valve means in the flow dosing position to meter the refrigerant flow from the evaporator to the condenser, adjusting the reversing valve to direct refrigerant vapor from the compressor to the evaporator for defrosting the latter, re-opening the first valve means to allow free flow of refrigerant from the evaporator to the evaporator. condenser while maintaining the inversion valve in a position such that the refrigerant vapor is pumped to the evaporator, to pump the excess refrigerant liqui25 evaporator area to the   condenser, returning the first valve means to a position opposing flow resistance to meter the flow of coolant from the condenser to the evaporator, and repositioning the reversing valve to refrigerant vapor from the compressor to the condenser.   7. A method of operating a heat pump having indoor and outdoor heat exchangers (16, 18) alternately operating as an evaporator and a condenser in cooling and heating modes, respectively, a compressor (14), pipes Refrigerant fluid (34, 36, 38, 40) disposed between the heat exchangers and the compressor, an inverting valve (32) having first and second positions for directing refrigerant fluid from the compressor to the heat exchanger outside in a first mode of operation and to the indoor heat exchanger in the second mode of operation, respectively, and a dual flow expander assembly (12) mounted in a refrigerant line (40) between the indoor heat exchangers and exterior to meter the flow of refrigerant in one direction or the other between the heat exchangers and allow e a virtually free flow of refrigerant in the refrigerant line 15 between the heat exchangers, the method being characterized in that it consists in placing the inversion valve in the position directing the refrigerant vapor towards the heat exchanger. In order to allow a substantially free flow of refrigerant fluid between the heat exchangers, to operate the compressor to flush the refrigerant liquid through the heat exchanger, the evaporator heat system operates during the desired operating mode. heat exchanger 25 which operates as an evaporator during the desired operating mode to the heat exchanger which operates as a condenser during the desired operating mode, to place the dual flow expander assembly in a position dosing the flow of the fluid refrigerant between heat exchangers,   and placing the inversion valve in the position directing the refrigerant vapor to the heat exchanger that operates as a condenser during the desired operating mode.   The method of claim 7, wherein the heat pump is operating in the second mode of operation while the indoor heat exchanger is operating as a condenser and the external heat exchanger is operating as an evaporator, characterized in that it further comprises adjusting the dual flow expander assembly so that free flow of the inner heat exchanger to the outer heat exchanger can pass through while maintaining the inversion valve in the second mode. In operation, flow of refrigerant from the indoor heat exchanger to the outdoor heat exchanger through the dual flow expander assembly, place the inversion valve in the first operating mode and adjust dual flow regulator assembly for dosing refrigerant flow from the outdoor heat exchanger to the indoor heat exchanger To operate the compressor to defrost the outdoor heat exchanger, re-adjust the dual flow expander assembly to allow free flow through the refrigerant line of the outdoor heat exchanger to the outlet. heat exchanger interior while maintaining the inversion valve in the first operating mode, flowing the refrigerant fluid from the outdoor heat exchanger to the indoor heat exchanger through the dual flow expander assembly, and to return the inversion valve to the second operating mode and the en30 appears dual flow regulator in the position dosing the flow of refrigerant from the indoor heat exchanger to the outdoor heat exchanger. A method of defrosting a heat pump comprising an evaporator (16 or 18), a condenser (16 or 18), a compressor (14), refrigerant fluid lines (34, 36, 38, 40) disposed between the compressor and the evaporator, between the compressor and the condenser and between the evaporator and the condenser, and throttling means (42, 44) for dosing the flow of refrigerant on paths from the evaporator to the condenser and condenser to the evaporator, the method being characterized in that it consists in allowing a free flow of the coolant managing fluid on a path from the condenser to the evaporator, to flush the coolant condenser to the condenser. evaporator, to throttle the flow of refrigerant on a path from the evaporator to the condenser, to operate the heat pump in a conventional defrost mode by directing the refrigerant vapor of the compressor to the evaporator, to allow a free flow of refrigerant on a path from the evaporator to the condenser, to flow the coolant from the evaporator 20 to the condenser, to restrict the flow of refrigerant on a path of from the condenser to the evaporator, and to resume the conventional operation of the pump heat.   10. An air conditioning apparatus comprising first and second heat exchangers (16, 18), one of which works as an evaporator and the other as a condenser, a compressor (14), pipes (34, 36, 38). 40) arranged between the heat exchangers and between the compressor and the heat exchangers, and an inverting valve (32)   intended to direct the refrigerant fluid of the compressor towards one or the other of the heat exchangers, the apparatus being characterized in that it comprises means (12) triggered for a short period of time, at startup, for flush the refrigerant fluid   manager of the heat exchanger working in the evaporator, to the heat exchanger working in condenser.   11. Apparatus according to claim 10, characterized in that the means pouring the refrigerant fluid comprise a dual flow expander assembly (12) disposed in the pipe (40) of coolant between the first and second heat exchangers, this dual flow regulator assembly 10 being traversed by a first channel   (42 or 44) for dosing the flow of coolant between the first and second heat exchangers, and a second path (46) for the flow of coolant between the first and second heat exchangers without this set double flow regulator opposes a sensible resistance to this flow.   12. A method for quickly establishing the steady state of operation of a heat pump installation having a low pressure portion and a high pressure portion, characterized in that it consists, at startup, in establishing a substantially free for the flow of a refrigerant fluid from the low pressure portion of the installation to the high pressure portion, to flush the refrigerant 25 from the low pressure portion to the high pressure portion   pressure of the plant, and to establish a flow resistance path for dosing the flow of refrigerant from the high pressure portion to the low pressure portion of the plant.