KR830001524B1 - Operation method for multiple compressor heat pump with coordinated defrost - Google Patents

Abstract

The electrical control means provides for a second compressor being energized when the outdoor heat exchanger of a first compressor is being defrosted and the first and second contact means located within the individual defrost circuits for the first and second outdoor heat exchanger is being defrosted the second outdoor heat exchanger maynot commence a defrost cycle and when the second compressor is being operated in a defrost cycle a first compressor may not commence a defrost cycle.

Description

How to operate a multi-compressor heat pump of equivalent design

1 is a schematic diagram of a heat pump apparatus using two compressors, two internal heat exchangers and two external heat exchangers.

2 is an electrical circuit diagram showing a circuit for adjusting the operation of a compressor used in the heat pump apparatus shown in FIG.

The present invention relates to a heat pump control method, and in particular to a control method for coordinating defrosting operations of two compressor heat pump devices.

The use of two compressor heat pumps is advantageous because it allows the compressor to run independently to control the input of energy required for the required cooling and heating operations. As used herein, the term "heat pump" refers to a heating chiller that can deliver heating or cooling as required to an area where air is matched. Most small heat pump units use only one compressor. In such a device, only one compressor is used, which is relatively simple and causes little problems. However, in very large heat pump devices, two compressors are used to supply refrigerant through a closed loop circuit.

In a heat pump apparatus using two compressors, it is common for the compressor to operate in sequence as the cooling load of the apparatus increases, allowing the compressor to operate when the heat pump is in the process of cooling operation. However, angular compressors usually operate when the device supplies heat to a zone where air is harmonized, regardless of the heating requirements of the device. In the heated state, the compressor operates primarily to prevent the cyclic load on the compressor as the device transitions to the defrost cycle. As is well known in the art, it is typical during the defrost process, which is typical of compressed air when the external fan is turned off. Starting one will force the device to operate under the opposite conditions, which can damage the device.

However, continuous operation of various problems associated with the defrosting operation causes other problems that cause unnecessary energy waste and damage to the device. US patent application 739,398 describes a heat pump control device for operating a dual compressor device during a heating operation. The patent application shows an electrical circuit including a frost control device, in which one or two compressors are operated to encounter a heating load sensed by a temperature control device. The device of the patent application states that the external heat exchangers are defrosted at the same time if it is necessary to remove the frost. The need for defrost is determined by making the temperature of the refrigerant in each device uniform. If only one compressor is running, then the other compressors are operated when defrosting is required so that the two compressors work together in the cooling process.

The present invention relates to a method in which each external heat exchanger defrosts independently of each other as well as allowing the two compressors to operate properly during the heating operation. The provided electrical control circuit drives the second compressor, in which the first compressor operates within the defrost cycle, where the air is conditioned even though the second compressor is operated in the cooling process to remove frost from the external heat exchanger. Are supplied openly. In addition, if one of the compressors is operated in a defrost cycle, each relay contact is provided in each defrost system to prevent the other compressor from starting the defrost cycle. As a result, during the heating operation, one compressor always supplies heat to the area where the air is to be coordinated despite the operation of the other compressor.

It is an object of the present invention to provide a method of controlling a heat pump for a multiple compressor heat pump device.

Another object of the present invention is to provide such a control method for allowing the heat pump to perform independently during the heating operation.

It is a further object of the present invention to provide a method of operating a multiple compressor heat pump in which the operation of each compressor is adjusted such that only one compressor is in the defrost operation at any time.

Another object of the present invention is to minimize the energy loss generated in the heat pump apparatus due to the use of multiple compressors.

It is another object of the present invention to operate a method of operating two compressor heat pumps operated by a second compressor to supply heat to an air-conditioned area despite the load condition when the first compressor is in a defrost operation. To provide.

It is a further object of the present invention to provide a method of operating each compressor of two heat pump apparatuses according to the initial heating requirements when the external ambient temperature drops below a predetermined level.

Another object of the present invention is to provide a reliable, economical and permanent control method for adjusting a multiple compressor heat pump apparatus.

The above and other objects will be clearly understood by reading the following description and claims.

The above objects are achieved according to the invention by installing a heat pump apparatus having a first and a second compressor, a first internal heat exchanger. The heat exchanger is used to provide heating and cooling to the air conditioned area. The first and second external heat exchangers are connected to operate in a suitable compressor and internal heat exchanger to form a closed circuit of the fluid refrigerant. A first and second defroster to remove accumulated ice from the external heat exchanger, a thermostat to operate the compressor at a suitable temperature, and a first external heat exchanger connected to the first compressor by operating the first defroster. A first control circuit for ignoring the temperature regulator and starting the second compressor, regardless of the temperature of the region in which the air is conditioned, and operating the second defroster to operate on the second compressor. Also provided is a second defrost control circuit or the like that initiates a defrost cycle for the second external heat exchanger. Normally closed first defrost relay contacts connected to the first defrost control circuit are used to prevent the defrost cycle from starting when the second defrost control circuit is within the defrost cycle. When in the defrost cycle, normally closed second defrost relay contacts connected to the second defrost control circuit are used to prevent the defrost cycle from starting. Relay contacts are provided to deactivate the reversible valves and the appropriate external heat exchanger fan when the device is operated within the defrost operation. An external thermostat connected to a heating relay keeps all the compressors running at the same time when the ambient temperature drops below a predetermined level to ensure proper room temperature. The auxiliary heater is then activated as the room temperature changes.

In particular, the preferred embodiment described below is intended for good use with two compressor heat pump devices. The following description is applicable to all types of multiple compressor heat pumps utilizing independent defrost cycles for external heat exchangers without departing from the scope of the present invention. The size, load requirements and end use of each heat pump device do not affect the scope of the present invention as described below. Referring to the drawings, FIG. 1 shows that the compressor 19 is connected to an internal heat exchanger 17 and an external heat exchanger 13 through a reversible valve 21. It is also shown that the compressor 20 is connected to the internal heat exchanger 16 and the external heat exchanger 14 via a reversible valve 23. Expansion valves 28 and 29 are provided in circuits in which internal and external heat exchangers and respective compressors are connected to each other.

In the cooling mode in operation, the reversible valve flows a hot refrigerant in a gaseous state to an external heat exchanger, where the gaseous refrigerant is condensed in a liquid state. The condensed liquid flow from the external heat exchanger is throttled through the expansion valve and the pressure drops. At this time, the refrigerant is converted into a vapor state in the internal heat exchanger to absorb heat from the air passing through the heat exchanger. Then one cycle is completed as the gaseous refrigerant is returned to the compressor.

In the heating mode during operation, the compressed gaseous refrigerant is first sent to an internal heat exchanger, where it condenses into a liquid state while providing condensation heat to the air-conditioned area. At this time, the liquid refrigerant from the internal heat exchanger enters the external heat exchanger through the expansion valve, where the liquid refrigerant evaporates while absorbing heat from the outside air before returning to the compressor as a gas. Each heat pump circuit in the device operates in the same way.

Referring to FIG. ₂ , it can be seen that the line voltage is supplied to the electric circuit through L ₁ and L ₂ . Compressor motors marked 1CM and 2CM (usually three-phase, connected by three wires but shown here for convenience only) are connected to line voltage by relay contacts CR-1 and 2CR-1. Relay contact 1CR-1 is a pore motor 1CM, a normally closed first defrost relay contact 1DFR-1, a normally open first defrost relay contact 1DFR-2 and a normally closed second defrost relay Connect with contact 2DFR -1. The first defrost relay contact 1DFR-1 is connected to the first external heat exchanger fan motor 1HFM and the normally open reversible relay contact 1RVR-2. The normally open relay contact 1RVR-2 for the reversible valve is connected to the first reversible valve 1RV. The first defrost relay contact 1DFR-2 is connected to the normally open defrost timer contact 1DF-1 and the normally closed defrost timer contact 1DF-2. The normally closed second defrost relay contact 2DFR-1 is connected to the contact 1DF-1 and the first defrost timer 1DT. The normally closed defrost timer contact 1DF-2 is connected to the first defrost thermostat 1DFT, and the thermostat 1DFT is connected to the first defrost relay 1DFR.

Relay contact 2 CR-1 and the first defrost relay contact 1DFR-3 are the second compressor motor 2CM, normally closed second defrost contact 2DFR-2. It is connected to the normally open second defrost relay contact 2DFR-2 and the normally closed second defrost relay contact DFR-4. The second defrost relay contact 2DFR-2 is connected to the second reversible valve 2RV via the second external heat exchanger fan motor 2HFM. The second defrost relay contact 2DFR-3 is connected to the normally defrosted second defrost timer contact 2DT-1 and the normally closed second defrost timer contact 2DT-2. The first defrost relay contact 1DFR-4 is connected to the normally defrosted second defrost timer contact 2DT-1 and the second defrost timer 2DT. The normally closed second defrost timer contact 2DT-2 is connected to the second defrost thermostat 2DFT, and the thermostat 2DFT is connected to the second defrost relay 2DFR.

Transformer T-1 supplies the control current from the line portion of the circuit to the control portion of the circuit. Within the control section of the circuit is a thermostat with a series of four switches (SW-1 through SW-4). The switch SW-1 of the thermostat is connected to the normally open reversible relay contact RVR-1, the normally open relay relay HR-1 and the first compressor relay. The switch SW-2 of the normally open thermostat is connected to the normally open heating relay contact HR-1, the normally closed heating relay contact HR-3 and the second compressor relay 2CR. The switch SW-4 is connected to a normally closed heating relay contact HR-3 and a normally open heating relay contact HR-2, which is connected to an additional heating source SH which is a typical electrical resistance heater. The switch SW-3 is connected to the relay 1RVR for the reversible valve and an adjustable external temperature controller AOT, which is connected to the heating relay HR. The relay contact RVR-1 for the reversible valve is connected to transformer T-1, the normally open thermostat switch SW-1, the relay 1CR for the first compressor and the normally open relay contact HR-1.

During operation, the switch SW-1 closes when it detects that the cooling is insufficient, and the relay 1CR for the first compressor activates the first compressor motor. 2 Compressor relay 2CR operates the second compressor motor. During the cooling process, the frost does not need to be removed and as a result the rest of the circuit is not used.

In the heating process, if it detects that the heating is insufficient, the switch SW-3 is closed, the relay 1RVR for the reversible valve is activated and the relay contact RVR-1 for the appropriate reversible valve is closed. When contact RVR-1 is closed, relay 1CR for the first compressor, which continues to operate the first compressor motor, is activated. The relay contact 1RVR-2 for the reversible valve is also operated by the relay 1RVR for the reversible valve, the first reversible valve 1RV is activated by the operation of the 1RVR-2, and the first compressor system is operated in the heating operation process. During operation, the first defrost timer 1DT is energized through a normally closed second defrost relay contact 2DFR-1. After a predetermined period of time, the first defrost timer 2DT closes the hot spot 1DF-1 and also allows the contact 1DF-2 to remain closed for a selected defrost time of about 10 minutes. If the first defrosting thermostat 1DFT detects the need to remove frost by checking the temperature of the refrigerant or by using another device that detects ice accumulation in the outside nose routine, the first defrost temperature The regulating device 1DFT is closed and then the first defrosting relay 1DFR is activated during the period that the defrost timer contacts 1DF-1 and 1DF-2 are closed. Once the first defrost relay 1DFR is activated, the first defrost relay contact 1DFR-1 is opened to allow the first external heat exchanger fan motor to operate discontinuously and remove energy from the first reversible valve, thus cooling the system. It works by the operation process and supplies heat to the external coil. When the first defrost relay contact 1DFR-2 is closed to provide a passage of current, the first defrost relay 1DFR operates continuously until the defrost thermostat detects and removes the ice. do. At this time, the first defrosting relay contact 1DFR-2 is opened, the first defrosting relay 1DFR stops operation, thereby defrosting to determine whether the first defrosting thermostat 1DFT is closed. Timer 1DT will continue to stop deactivation until another procedure is performed. Normally closed second defrost relay contact 2 DFR-1, if the second defrost relay 2DFR in the second compressor circuit operates while indicating that the second circuit is within the defrost cycle, The timer 1DT is provided such that it cannot be started. Defrost also ends when the defrost timer expires such a delay period during which energy is removed from the first defrost relay by opening contact 1DF-2.

The operation of the second compressor circuit is similar to the first compressor circuit. If the need for further heating is detected, energy is supplied to the relay 2CR for the second compressor via the closed heating relay contact HR-3 with the switch SW-4 closing. Subsequently, the relay contact 2CR-1 for driving the second compressor motor is closed. The motor for the second compressor is also energized via the first defrost relay contact 1DFR-3. When the first compressor is operated in the defrost process, the first defrost relay 1DFR operates to close the first defrost relay contact 1DFR-3, and then the second compressor motor is in the cooling process to remove the frost. Although the first compressor motor is operated it will be operated to supply heat from the second compressor to the internal coil. When relay contact 2CR-1 or primary defrost relay contact 1DFR-3 is activated, the second external heat exchanger fan motor 2HFM is operated via normally closed contact 2DFR-2 and relay contact RVR-3 for closed reversible valves. do. The second defrost timer 2DT remains in a state in which the contact 2DT-1 is closed for the predetermined period and the contact 2DT-2 is closed until the predetermined period is completed through the normally closed first defrost relay relay 1DFR-4. It works to keep it going. The second defrost timer contact 2DT-1 operates when the second defrost relay is closed when the second defrost temperature controller is closed. During this period, about 10 seconds after the second defrost timer 2DT is tripped. Will remain closed for a while. When the second defrost relay 2DFR is activated, the contact 2DFR-2 is opened, which causes the second reversible valve and the second external heat exchanger fan motor to stop operating. The second defrost relay contact 2DFR-3 is closed to form a closed circuit through contact 2DT-2 and the second defrost thermostat to continue to operate the second defrost relay 2DFR. When the second defrosting thermostat senses that it is no longer necessary to remove the defrost, the thermostat is opened to discontinuously operate the second defrost relay. The second defrost timer contact 2DT-2 is opened after a predetermined period of about 10 minutes has expired, thereby completing the defrost work. The first defrost relay contact 1DFR-4 is arranged such that when the first compressor is in the defrost operation, the contact 1DFR-4 is opened and subsequently no current flows to the second defrost timer to achieve a defrost circuit. do. These contacts serve the same purpose as contact 2DFR-1 in the first compressor circuit.

An adjustable external thermostat ADT is provided to change the operation of the device when the external ambient temperature is below a predetermined level. When the external thermostat ADT is closed, the heating relay HR is then activated when the switch SW-3 is closed. Thus, contacts HR-1 and HR-2 are closed and contacts HR-3 are open. When the contact HR-1 is closed, the 1CR and 2CR operate simultaneously, and the compressors operate simultaneously to supply heat to the air conditioned area, depending on the initial heating requirements. When the room temperature is no longer intensified, the switch SW-4 is closed and an auxiliary heater, typically an electric resistance heater, is activated. The contact HR-3 is opened and as a result the auxiliary heater is started regardless of the operation of the compressor. The net effect of the heating relay is to open and close the heating pump device in accordance with the external ambient temperature, from the operation of the appropriate compressor to the proper operation between the compressor and the subheater.

It is already known that an electrical control circuit is provided within the heating operation stage which drives the compressor motor step by step. The electrical control circuit allows only the first compressor to operate when the heating load is satisfactory and the second compressor motor to operate when the heating load increases. In addition, the first compressor motor control circuit has a device that allows the first compressor motor to operate in a defrost process to drive the second compressor motor when heat continues to be supplied to an area where air is to be balanced. When the first defrost relay is activated, the relay stops the operation of the second defrost relay, and conversely, each relay contact is provided in each circuit such that only one external heat exchanger is defrosted at any particular time.

While the invention described above has been described with reference to the accompanying drawings, it will be understood that modifications and variations may be applied within the scope of the following claims.

Claims (1)

A plurality of compressors (19, 20), a plurality of external heat exchangers (13, 14) connected to operate with the compressor, a plurality of light defrosts for the internal heat exchangers (16, 17), suitable external heat exchangers (13, 14) It is connected to each other with the relays (1DFR, 2DFR), a plurality of fans connected to a suitable heat exchanger, and each compressor and thermostat which operates the compressor at a suitable temperature, and changes the direction of refrigerant flow in the heat pump. In the known method of operating a plurality of compressor heat pumps composed of a plurality of reversible valves (21, 23) to make, the appropriate operation process and the number of compressors are selected to allow the device to operate while performing the proper function, The first compressor 19 is operated to transfer heat between the first internal heat exchanger 17 and the first external heat exchanger 13 under an appropriate load condition, and the second compressor 20 is operated to operate the first external heat exchanger ( 13) dragon When the first defrost relay 1DFR is operated, heat is transferred from the second subheat exchanger 14 to the second internal heat exchanger 16, and both the first and second compressors 19 and 20 are operated. To transfer heat between the first and second external heat exchangers (13, 14) and the first and second internal heat exchangers (17, 16) under moderate load, and to remove the first frost connected to the first compressor (19). When the relay 1DFR is operated, the operation of the second defrosting relay 2DFR connected to the second compressor 20 is stopped and the second defrosting relay 2DFR connected to the second compressor 20 is operated. A method of operating a multiple compressor heat pump of equivalent design, characterized in that the first defrost relay (1DFR) connected to the compressor (19) is deactivated.

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