KR830001525B1 - Multiple compressor heat pump with coordinated defrost - Google Patents

Abstract

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Description

Equal Design Multiple Compressor Heat Pumps

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 device, in particular a control device for equally adjusting the defrost operation 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 reversible 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 course of cooling operation. However, each compressor is usually operated when the device supplies heat to a zone where air is matched regardless of the heating requirements of the device. In the heated state, the compressor is primarily operated to prevent the cyclic load on the compressor as the device transitions to the defrost cycle. As is well known in the art, starting one of the compressors when the external fan is off, which is typical during defrosting, forces the device to operate under opposite conditions, which can damage the device.

However, continuous operation of the compressors to overcome the various problems associated with defrosting causes other problems that cause unnecessary energy waste and damage to the apparatus. U.S. Patent No. 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 defroster, where one or two compressors are operated to encounter a heating load sensed by the temperature controller. 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 operated, then the other compressors are operated when defrosting is required so that the two compressors work together in the cooling process.

The apparatus relates to each external heat exchanger defrosting independently of each other as well as to allow the two compressor units 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. Heat is supplied. 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.

An object of the present invention is to provide a control apparatus of a heat pump for a multiple compressor heat pump apparatus.

Another object of the present invention is to provide such a control device that allows the heat pump to be performed independently during the heating operation.

It is a further object of the present invention to provide a multiple compressor heat pump apparatus in which the operation of each compressor is adjusted so 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 a plurality of compressors.

It is a further object of the present invention to provide two compressor heat pump devices in which the second compressor is operated to supply heat to the air-conditioned area despite the load condition when the first compressor is in the defrost operation. .

Another object of the present invention is to operate each compressor of the 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 device for adjusting to a multiple compressor heat pump device.

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 and a second 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 for removing accumulated ice from the external heat exchanger, a temperature controller for operating the compressor at a suitable temperature, and a first external heat exchanger connected to operate the first compressor by operating the first defroster. Start the first defrost cycle and start the second compressor by ignoring the temperature controller regardless of the temperature in the air conditioning zone, and then operate the second defroster to operate 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 stop the reversible valves and the appropriate external heat exchanger fan when the device is operating within the defrost operation. An external thermostat connected to a heating relay keeps all the compressors running at the same time, keeping the proper room temperature when the ambient temperature drops below a predetermined level. Thereafter, the auxiliary heater is operated in accordance with the change of the room temperature.

In particular the preferred embodiment described below is intended to be used well with two compressor heat pump apparatus. The following description is applicable to all types of multiple compressor heat pumps utilizing independent defrost cycles for each external heat exchanger 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 the internal heat exchanger 17 and the external heat exchanger 13 via 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 allows a high temperature refrigerant in gaseous state to flow 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 of operation, the compressed gaseous refrigerant is first sent to an internal heat exchanger, where it condenses from the gaseous state into the liquid state while providing the heat of condensation to the area where the air is conditioned. 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 external 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 phases are connected to three wires but are shown here only as one connection for convenience) are connected to line voltage by relay contacts 1CR-1 and 2CR-1. Relay contact 1CR-1 is compressor motor 1CM, normally closed defrost relay contact 1DFR-1, normally open defrost relay contact 1DFR-2 and normally closed defrost relay contact 2DFR- Is connected to 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 2CR-1 and first defrost relay contact 1DFR-3 are the second compressor motor 2CM, normally closed second defrost relay contact 2DFR-2, normally open defrost relay contact 2DFR-3 And a normally closed first defrost relay contact 1DFR-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 open 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 open 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 contact HR-1 and the first compressor relay. The normally open thermostat switch SW-2 is connected to a normally open heating relay contact HR-1, a normally closed heating relay contact HR-3 and a second compressor relay 2CR. The switch SW-4 is connected to the normally closed heating relay contact HR-3 and the normally open heating relay contact HR-2, which is connected to an additional heating source SH which is a typical electrical resistance heater. Switch SW-3 is connected to relay 1RVR for reversible valves and an adjustable external thermostat AOT, and the thermostat AOT 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, if the switch detects lack of cooling, the switch SW-1 closes, and the relay 1CR for the first compressor activates the first compressor motor. The relay 2CR for the two compressors activates the second compressor motor. During the cooling process, frost does not have to be removed, and the rest of the circuit is not used extensively.

In the heating process, if it detects that the heating is insufficient, the switch SW-3 is closed and 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 operated by the operation of the 1RVR-2, and the first compressor system is operated in the heating operation process. In 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 1DT closes contact 1DF-1 and also causes contact 1DF-2 to remain closed for a predetermined defrost time of about 10 minutes. If the first defrost thermostat 1DFT detects the need to remove frost by checking the temperature of the coolant or by using another device that detects ice buildup on the outer coil, The thermostat 1DFT is closed and the first defrost relay 1DFR is activated during the defrost timer contacts 1DF1 and 1DF-2, which 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. It operates by cooling operation to supply heat to 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 that time, the first defrosting relay contact 1DFR-2 is opened and the first defrosting relay 1DFR stops operating. In doing so, the defrosting to check whether the first defrosting thermostat 1DFT is closed is performed. The defrost timer continues to stop defrost until the other DT performs another procedure. Normally closed second defrost relay contact 2DFR-1 is the first defrost timer if the second defrost relay 2DFR in the second compressor circuit operates while indicating that the second circuit is within the defrost cycle. The 1DT is provided to be inoperable. Defrost also ends when such a delay period during which energy is removed from the first defrost relay by opening the defrost timer 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 first defrost relay contact 1DFR-3 is activated, the second external heat exchanger fan motor 2HFM is operated via a normally closed second defrost relay contact 2DFR-2. The second reversible valve is operated via a normally closed contact 2DFR-2 and a relay contact RVR-3 for the closed reversible valve. The second defrost timer 2DT is normally closed through the first defrost relay contact 1DFR-4, which is normally closed for a predetermined period of time until the predetermined period expires, and the contact 2DT-2 is closed. It works to keep it going. For the second defrost timer contact 2DT-1, the second defrost relay is activated when the second defrost temperature controller is closed for about 10 seconds after the second defrost timer 2DT trips. It will remain closed. When the second defrost relay 2DFR is activated, the contact 2DFR-2 is opened so that the second reversible valve and the second external heat exchanger fan motor stop working. The second defrost relay contact 2DFR-3 is closed so that the contact 2DT-2 forms a closed circuit through 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 opens to discontinuously operate the second defrost relay. The second defrost timer contact 2DT-2 is opened after the 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 prevent defrost circuitry. . These contacts serve the same purpose as contact 2DFR-1 in the first compressor circuit.

An adjustable external thermostat AOT is provided to change the operation of the device when the external ambient temperature is below a predetermined level. When the external thermostat AOT 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 drops further, the switch SW-4 is closed and the auxiliary heater, typically an electric resistance heater, is activated. The contact HR-3 is opened and the hanger and auxiliary heater are 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 a raised control circuit is provided in 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 porter control circuit has a device that allows the first compressor motor to operate in the defrost process to drive the first 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 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)

Interoperable with the first and second internal heat exchangers (17,16) and the first and second external heat exchangers (13,14), the internal and external heat exchangers, which provide heating and cooling to the air conditioned area. First and second defrosting relays (1DFR, 2DFR) provided to remove ice from the connected first and second compressors (19,20) and external heat exchangers and thermostats to operate the compressor at a suitable temperature. In a known heat pump apparatus using a refrigerant having a), the defrost cycle for the first external heat exchanger (13) connected to the first compressor (19) is started during operation of the first compressor (19). A first defrost control circuit for operating the first defrosting relay (1DFR) and starting the second compressor (20) regardless of the temperature in the region where air is harmonized, and a second outside connected to the second compressor (20). Let's start the defrost cycle for the heat exchanger (14) Is a second defrost control circuit for operating the second defrost relay (2DFR), and a second defrost control circuit connected to the first defrost control circuit to prevent the start of the defrost cycle when the second defrost control circuit is within the defrost cycle. 2 Defrost relay contact (1DFR-1), the first defrost relay contact (1DFR) connected to the second defrost control circuit to prevent the start of the defrost cycle when the first defrost control circuit is within the defrost cycle. -4) Multiple compressor heat pump of equivalent design, characterized in that consisting of.

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