JP2730934B2 - Heat pump refrigeration system - Google Patents

Description

The present invention relates to a heat pump type refrigerating apparatus for driving a compressor by an engine, and more particularly to a heat pump type refrigerating apparatus suitable for cooling and heating a plurality of rooms.

(B) Conventional technology The heating capacity of a heat pump refrigeration system that uses outside air as a heat source varies depending on the outside air temperature and humidity. When the outside air temperature decreases, the heating capacity also decreases.

For this reason, as presented in Japanese Utility Model Publication No. 60-116161,
Attempts have been made to integrate the radiator through which the engine exhaust heat passes into the outdoor heat exchanger, recover the heat of the engine exhaust heat during heating, and improve the heating capacity even when the outside temperature drops. .

(C) Problems to be Solved by the Invention In the device presented in the above publication, heat exchange between the exhaust heat water of the engine and the refrigerant is not performed directly, so that only a part of the heat amount of the exhaust heat water can be used for heating. The present invention is to provide a heat pump refrigeration apparatus that solves the above problem.

(D) Means for Solving the Problems In order to achieve the above object, the present invention sequentially interposes an auxiliary pressure reducing element and a heat exchanger for recovering exhaust heat of an engine in a branch line branched from a high-pressure liquid pipe. The other end of the branch pipe is connected to the refrigerant suction side of the compressor, and the refrigerant suction pressure of the compressor is opened below the set pressure during the cooling operation, and the outside air temperature is set during the heating operation. A valve that opens below the temperature is provided.

(E) Function When the outside air temperature decreases during heating operation, the amount of heat pumped from the outside air decreases and the heating capacity decreases, the branch pipe valve opens, and a part of the high-pressure liquid refrigerant recovers the exhaust heat from the auxiliary pressure reducing element and the engine. Auxiliary heating operation, which returns to the compressor via the heat exchanger for air, is started, and the heat retained by the exhaust heat water of the engine is directly recovered by the refrigerant, so the heat source by the exhaust heat water of the engine as well as the air heat source is heated The heating capacity does not decrease even if the outside air temperature decreases.

(F) Embodiment The present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes an outdoor unit having a machine room 2 at a lower portion and a heat exchanger room 3 at an upper portion, and 4A, 4B, and 4C are indoor units. These units are connected by gas pipe 5, gas side unit pipes 5A, 5B, 5C, high pressure liquid pipe 6, and liquid side unit pipes 6A, 6B, 6C.

7 is an engine, 8 is a compressor driven by the engine 7, 9 is a four-way switching valve for switching the refrigerant flow path, 10 is a gas pipe side closing valve provided in the gas pipe 5, 11A, 11B and 11C are gas side. Electromagnetic gas-side on-off valve provided in unit piping 5A, 5B, 5C, 12A, 12
B and 12C are indoor heat exchangers forcibly exchanging heat with indoor air and indoor fans 13A, 13B and 13C, respectively, 14A, 14B and 14C are expansion valves for cooling, and 15A, 15B and 15C are check valves for heating. , 16A, 16B, 16C are electromagnetic liquid-side on-off valves provided on the liquid-side unit piping 6A, 6B, 6C, 17 is a liquid-tube-side closing valve provided on the high-pressure liquid pipe 6, 18 is a receiver tank, and 19 is a receiver tank. A pressure reducing element comprising a heating expansion valve having a temperature sensing part 20, a cooling check valve 21, an outdoor heat exchanger 22 for forcibly exchanging heat with outdoor air and an outdoor fan 23, and 24 an accumulator. , These are connected in a ring to the pipe. Reference numeral 25 denotes a hot gas bypass pipe which communicates a discharge port and a suction port of the compressor 8, and is provided with an electromagnetic valve 26 which is opened for a predetermined time when the compressor 8 is started.

Reference numeral 27 denotes a bypass pipe which is provided so as to straddle a high pressure liquid pipe 6 and a pipe 29 on the upstream side of the refrigerant pipe 28 to which the temperature sensing part 20 of the expansion valve 19 is attached during the heating operation. Is a refrigerant pressure reducing element 30 such as a capillary tube and an indoor unit.
An electromagnetic valve 31 that is opened and closed by the number of operating units 4A, 4B, and 4C, an on-off valve 32 that opens when the pressure is equal to or higher than a set pressure, and a check valve 33 are provided. Reference numeral 34 denotes a first bypass which connects the high-pressure liquid pipe 6 between the liquid pipe side closing valve 17 and the receiver tank 18 and a pipe on the upstream side of the accumulator 24.
A capillary tube 36 and an auxiliary evaporator 37 are sequentially provided.

Reference numeral 38 denotes a second bypass passage connecting the gas pipe 5 between the four-way switching valve 9 and the gas pipe side closing valve 10 and the refrigerant pipe between the heating pressure reducing element 19 and the outdoor heat exchanger 22; When the pressure is equal to or higher than the set pressure, fertilizing pressure adjusting valves 39 and 40, a check valve 41 and an electromagnetic valve 42 are provided.

Reference numeral 43 denotes a branch pipe branched from the high-pressure liquid pipe 6. The branch pipe 43 is a solenoid valve 44 that is opened and closed during a heating operation, an auxiliary pressure reducing element 46 including an auxiliary heating expansion valve having a temperature sensing part 45, and a discharge port of the engine 7. This branch pipe is interposed sequentially with a heat exchanger 47 for heat recovery.
The other end of 43 is the refrigerant suction side of the compressor 8, for example, the four-way switching valve 9
And the accumulator 24.

Reference numeral 48 denotes a cooling water pipe of the engine 7. The cooling water from the circulating pump 49 flows through the cooling unit 50 of the engine 7 and rises in temperature, and then flows through the heat exchanger 47 for exhaust heat recovery.
When the outlet water temperature is below 50 ° C., it returns to the circulation pump 49 via the three-way valve 51, while when it exceeds 50 ° C., it opens to the first radiator 53 via the electromagnetic valve 52 which opens when heating, and opens when cooling. After flowing to the second radiator 55 via the electromagnetic valve 54, it returns to the circulation pump 49 via the three-way valve 51.

56, when the outside air temperature falls below the set temperature during heating,
This is detected by the temperature sensor 57, and the solenoid valve 44 is opened.
When the suction refrigerant pressure of the compressor 8 drops below the set pressure during cooling, the pressure sensor 58 detects this and controls the electromagnetic valve 44 to open.

 Next, the operation will be described.

When three indoor units 4A, 4B, and 4C perform the heating operation at the same time, the four-way switching valve 9 is in the solid line state, and the gas-side on-off valves 11A, 11B, and 11C, and the liquid-side on-off valves 16A, 16B, and 16C are open. Becomes Further, the engine 7 drives the compressor 8 at full speed. Compressor 8
The high-temperature and high-pressure gas refrigerant discharged from the pump is a four-way switching valve 9-gas side on-off valves 11A, 11B, 11C-indoor heat exchangers 12A, 12B, 12C-heating check valves 15A, 15B, 15C-liquid side on-off valves 16A, 16B, 16C-Receiver tank 18-Decompression element for heating 19-Outdoor heat exchanger 22-
The flow is returned to the compressor 8 via the four-way switching valve 9 and the accumulator 24 in order. By such an operation, the indoor heat exchanger 12A,
In 12B and 12C, the refrigerant condensing action is performed, and the indoor unit 4A,
Each room with 4B and 4C is heated individually. On the other hand, the outdoor heat exchanger 22 from which the refrigerant is evaporated draws this heating heat source from the outside air.

During the heating operation, when the outside air temperature falls below the set temperature, this is detected by the temperature sensor 57 and the electromagnetic valve 44 is opened by a signal issued from the control means 56, and a part of the high-pressure liquid refrigerant from the high-pressure liquid pipe 6 is released. Guided to branch line 43, auxiliary pressure reducing element
The auxiliary heating operation, which returns to the compressor 8 through the heat exchanger 46 for recovering the exhaust heat and the heat exchanger 46, is started. By this auxiliary heating operation, the heat retained in the exhaust heat water of the engine 7 is directly recovered by the refrigerant in the heat exchanger 47 for recovering the exhaust heat, the refrigerant is evaporated in the heat exchanger 47, and the heat is removed from the outside air in the outdoor heat exchanger 22. The heating operation is continued by the heating heat source to be pumped and the auxiliary heating heat source to be pumped from the engine exhaust heat water by the heat exchanger 47, so that the heating capacity does not decrease due to the decrease in the outside air temperature.

On the other hand, during the cooling operation, the four-way switching valve 9 is switched to the broken line state, and when the engine 7 is operated at a high speed, the compressor 8-the four-way switching valve 9-the outdoor heat exchanger 22-the cooling check valve-21-the receiver tank 18 -Liquid side on-off valves 16A, 16B, 16C-Cooling expansion valves 14A, 1
4B, 14C-Indoor heat exchanger 12A, 12B, 12C-Gas side on-off valve 11A, 1
1B, 11C-four-way switching valve 9-accumulator 24-compressor 8
The refrigerant circulates in this order, and each room is cooled by the refrigerant evaporating action in the indoor heat exchangers 12A, 12B, 12C.

During the cooling operation, when the number of operating indoor units 4A, 4B, and 4C decreases and the cooling load decreases, and the suction refrigerant pressure of the compressor 8 drops below the set pressure, this is detected by the pressure sensor 58 and the control means 56 The emitted signal causes the solenoid valve 44 to open, and a portion of the high-pressure liquid refrigerant from the high-pressure liquid pipe 6
To return to the compressor 8 via the auxiliary pressure reducing element 46 and the heat exchanger 47 for exhaust heat recovery. In the heat exchanger 47, the refrigerant is evaporated by the engine exhaust heat water to increase the low pressure. Therefore, for example, the indoor heat exchanger 12A of the indoor unit 4A that is performing the single cooling operation does not freeze.

In the above embodiment, the outside air temperature is detected during the heating as the input signal of the control means 56, but the pressure of the refrigerant discharged from the compressor 8 or the pressure of the suction refrigerant may be detected instead.

(G) Effects of the Invention According to the present invention, when the heating operation is performed during severe cold winter conditions where the outside air temperature is low, a part of the high-pressure liquid refrigerant is heat-exchanged with the heat exchanger for recovering the exhaust heat of the engine. Since the exhaust heat from the engine as well as the outside air is drawn as a heat source for heating, it is possible to prevent a decrease in the heating capacity at a low outside air temperature.

Also, when the cooling load decreases during the cooling operation, a part of the high-pressure liquid refrigerant is heat-exchanged with the heat exchanger for recovering the exhaust heat of the engine, so that the low-pressure refrigerant pressure is increased.
Freezing of the indoor heat exchanger can be prevented.

[Brief description of the drawings]

The drawing is a refrigerant circuit diagram of a heat pump refrigeration apparatus showing an embodiment of the present invention. 6 ... high-pressure liquid pipe, 7 ... engine, 8 ... compressor, 9 ...
… Four-way switching valve, 12A, 12B, 12C …… Indoor heat exchanger, 19 ……
Pressure reducing element, 22 …… Outdoor heat exchanger, 43 …… Branch line, 44…
... Valve, 46 ... Auxiliary pressure reducing element, 47 ... Heat exchanger for heat recovery.

Claims (1)

(57) [Claims] 1. A heat pump type refrigeration system in which a compressor driven by an engine is connected to a refrigerant pipe of an indoor heat exchanger, a pressure reducing element, and an outdoor heat exchanger via a four-way switching valve. An auxiliary pressure reducing element and a heat exchanger for recovering exhaust heat of the engine are sequentially interposed in a branch pipe branched from the liquid pipe, and the other end of the branch pipe is connected to the refrigerant suction side of the compressor. A heat pump type refrigerating apparatus, wherein a branch pipe line is provided with a valve that opens when a refrigerant suction pressure of the compressor is lower than a set pressure during a cooling operation and opens when an outside air temperature is lower than or equal to a set temperature during a heating operation.