JPH07174434A - Engine-driven heat pump - Google Patents

Abstract

PURPOSE:To reduce the size of an engine-driven heat pump and to improve the coefficient of performance by a method wherein ventilation is effected in the direction in which air passes a radiator through an outdoor heat- exchanger during cooling operation and in the direction in which air passes the outdoor heat-exchanger through the radiator during heating operation. CONSTITUTION:A radiator 21 and an outdoor heat-exchanger 5 are arranged in a state to be overlapped in the direction of an air flow passage. During cooling operation, the flow of air by an outdoor blower 16 is effected, in the order, of the outdoor heat-exchanger 5 and the radiator 21. The outdoor heat- exchanger 5 is prevented from being influenced by heat dissipation of the radiator 21. Further, during heating operation, the air direction is changed, the flow of air by the outdoor blower 16 is effected, in the order, of the radiator 21 and the outdoor heat-exchanger 5. The exhaust heat of an engine 1 is discharged by the radiator 21 and thereafter, heat is absorbed by the outdoor heat- exchanger 5. This constitution improves the coefficient of performance without increasing the scale of the outdoor heat-exchanger 5 on the freezing cycle side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine driven heat pump used as a refrigerator, an air conditioner or the like.

[0002]

2. Description of the Related Art FIG. 2 is a system diagram of a conventional engine-driven heat pump. In the figure, 1 is an engine, 2 is a coupling, 3 is a compressor, 4 is a four-way valve, 5 is an outdoor heat exchanger, 6 is an outdoor blower, 7a and 7b are check valves, and 8a and 8b.
Is an expansion valve, 9 is an indoor heat exchanger, 10 is a pump, and 11 is a radiator.

The compressor 3 uses the rotational output of the engine 1 as a power source via the coupling 2, and the exhaust heat of the engine 1 is the cooling water supplied by the pump 10 to the engine 1 and the radiator 11 as shown by the white arrow. The radiator 11 radiates heat by the air blown by the outdoor blower 6.

The refrigeration cycle is composed of a compressor 3, a four-way valve 4, an outdoor heat exchanger 5, check valves 7a and 7b, and expansion valves 8a and 8b. The refrigerant is shown by a solid arrow during cooling and by a dotted arrow during heating. Flows like.

During cooling, the gas refrigerant that has become high temperature and high pressure by the compressor 3 enters the outdoor heat exchanger 5 via the four-way valve 4. Here, heat is radiated to the air blown by the outdoor blower 6,
It condenses into a liquid refrigerant. After this, it enters the expansion valve 8a via the check valve 7a, is decompressed there, and enters the indoor heat exchanger 9.
Here, heat is absorbed from the room air and evaporated to become a gas refrigerant, and at this time, the room is cooled. After this, it returns to the compressor 3 via the four-way valve 4.

During heating, the gas refrigerant that has become high temperature and high pressure by the compressor 3 enters the indoor heat exchanger 9 through the four-way valve 4. Here, heat is dissipated to the room air and condensed to become liquid refrigerant,
At this time, the room is heated. After this, it enters the expansion valve 8b through the check valve 7b, where it is decompressed and enters the outdoor heat exchanger 5.
Here, the air blown by the outdoor blower 6 absorbs heat and evaporates to become a gas refrigerant. After this, it returns to the compressor 3 via the four-way valve 4.

[0007]

In the above conventional engine-driven heat pump, the exhaust heat of the engine 1 is radiated through the radiator 11 by the outdoor blower 6 of the outdoor unit. Therefore, the outdoor unit needs a space for the outdoor heat exchanger 5 and the radiator 11 on the refrigeration cycle side, and since the outdoor heat exchanger 5 and the radiator 11 are often installed close to each other, the outdoor heat exchanger 5 always radiates heat. Since it is affected by the radiator 11 that is operating, it must be upsized. Further, if the outdoor heat exchanger 5 and the radiator 11 are shared and downsized, the outdoor heat exchanger 5 is affected by the heat radiation of the radiator 11 and the coefficient of performance is lowered. Therefore, in the conventional engine-driven heat pump, the outdoor unit is upsized or the coefficient of performance is lowered.

The present invention is intended to reduce the size of an engine-driven heat pump and improve the coefficient of performance.

[0009]

Means for Solving the Problems The present invention has been made to solve the above problems, and a heat pump cycle is constituted by a compressor, a four-way valve, an outdoor heat exchanger, a throttle mechanism, and an indoor heat exchanger. In an engine-driven heat pump that drives a compressor by an engine, the present invention relates to an engine-driven heat pump having the following features. (1) An outdoor blower for arranging a radiator for discharging exhaust heat of the engine and an outdoor heat exchanger of the heat pump so as to be overlapped with each other in the direction of the air flow path, and for blowing air to the radiator and the outdoor heat exchanger. Install a device that can reverse the direction of air flow, and ventilate air through the outdoor heat exchanger through the outdoor heat exchanger during cooling and through the outdoor heat exchanger through the radiator during heating. (2) The engine-driven heat pump according to the above item (1) is provided with control means for controlling the rotation speed of the outdoor blower so that the low pressure of the refrigerant circuit becomes a set pressure during heating.

[0010]

According to the above-mentioned item (1) of the present invention, during cooling, heat can be radiated from the outdoor heat exchanger on the refrigeration cycle side without being affected by heat radiation from the radiator.
In addition, during heating, the heat released from the radiator is used to heat the air passing through the outdoor heat exchanger, increasing the heat absorption capacity of the outdoor heat exchanger on the refrigeration cycle side, improving the heating capacity and preventing frost formation on the outdoor heat exchanger. Is possible.

Further, the outside air temperature is lowered during heating, and the heat quantity of the air passing through the radiator is reduced. Therefore, if the wind speed is increased in an attempt to recover sufficient heat from the air after passing through the radiator in the outdoor heat exchanger on the refrigeration cycle side,
This will accelerate heat dissipation from the engine in the radiator more than necessary, leading to a drop in engine water temperature. In the item (2) of the present invention, the rotation speed of the outdoor blower is controlled so that the pressure becomes a preset low pressure in order to prevent heat radiation by the radiator more than necessary.

[0012]

FIG. 1 is a system diagram according to an embodiment of the present invention. In the figure, 16 is an outdoor blower, 21 is a radiator, 22
Is a control device. Other configurations are similar to those of the conventional one shown in FIG. 2, and corresponding members are designated by the same reference numerals. The outdoor blower 16 is a reversible fan that can blow air in the opposite direction, and generates a wind in the direction of arrow C during cooling and a wind in the direction of arrow H during heating. The radiator 21 and the outdoor heat exchanger 5 are arranged so as to overlap in the direction of the air flow path. The outdoor heat exchanger is arranged on the upstream side and the radiator is arranged on the downstream side with respect to the wind direction during cooling. The flow of the cooling water and the flow of the refrigerant are the same as the conventional ones.

In the present apparatus, during cooling, the flow of wind by the outdoor blower 16 causes the outdoor heat exchanger 5 and the radiator 21 to flow.
The outdoor heat exchanger 5 is configured not to be affected by the heat radiation of the radiator 21. During heating, the wind direction is changed and the wind flow by the outdoor blower 16 is changed by the radiator 2
1, the outdoor heat exchanger 5 is arranged in this order, the exhaust heat of the engine 1 is released by the radiator 21, and then the outdoor heat exchanger 5 absorbs the heat. At this time, the control device 22 controls the rotation speed of the outdoor blower 16 so that the low pressure is set in advance.

Since the present embodiment has the above-mentioned structure, the outdoor heat exchanger on the refrigeration cycle side can radiate heat without being affected by the radiator's heat radiation during cooling. When heating, the heat released from the radiator is used to heat the air passing through the outdoor heat exchanger, increasing the heat absorption capacity of the outdoor heat exchanger on the refrigeration cycle side and improving the heating capacity and preventing frost formation on the outdoor heat exchanger. . In addition, the outside air temperature decreases during heating, and the amount of heat of the air passing through the radiator decreases. Therefore, if the outdoor heat exchanger on the refrigeration cycle side attempts to recover sufficient heat from the air that has passed through the radiator and increases the wind speed, it will accelerate the heat radiation of the engine in the radiator more than necessary, and reduce the engine water temperature. Inspire. Therefore, in order to prevent the radiator from dissipating heat more than necessary, the rotation speed of the outdoor blower is controlled so that the low pressure on the refrigeration cycle side becomes a preset pressure.

[0015]

In the engine-driven heat pump according to the present invention, the radiator for discharging exhaust heat of the engine and the outdoor heat exchanger of the heat pump are arranged so as to overlap with each other in the direction of the air flow path thereof, and the radiator and the outdoor An outdoor blower that blows air to the heat exchanger is installed so that the air blow direction can be reversed.When cooling, the outdoor heat exchanger is passed through the radiator, and when heating, the radiator is passed through the outdoor heat exchanger. Since the air is ventilated in the direction of cooling, the coefficient of performance can be improved without increasing the size of the outdoor heat exchanger on the refrigeration cycle side, and the exhaust heat of the engine is radiated to the downstream flow of the outdoor heat exchanger during cooling, so Since the exhaust heat of the engine is radiated to the upstream of the outdoor heat exchanger during heating without any reduction in capacity, the outdoor heat exchanger can recover the exhaust heat of the engine and improve the heating capacity. Frost prevention to the outer heat exchanger is possible.

Further, in the one provided with the control means for controlling the rotation speed of the outdoor blower so that the low pressure of the refrigerant circuit becomes the set pressure, it is possible to prevent excessive exhaust heat of engine exhaust heat during heating. it can.

[Brief description of drawings]

FIG. 1 is a system diagram of an engine-driven heat pump according to an embodiment of the present invention.

FIG. 2 is a system diagram of a conventional engine-driven heat pump.

[Explanation of symbols]

 1 engine 2 coupling 3 compressor 4 four-way valve 5 outdoor heat exchanger 6 outdoor blower 7a, 7b check valve 8a, 8b expansion valve 9 indoor heat exchanger 10 pump 11 radiator 16 outdoor blower 21 radiator 22 controller C during cooling Wind direction H Wind direction during heating

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tadahiro Kato, Nishibiwajima-cho, Nishi-Kasugai-gun, Aichi Prefecture, Asahi-cho, 3-chome, Air-conditioning Plant, Mitsubishi Heavy Industries, Ltd. Asahi-cho 3-chome, Mitsubishi Heavy Industries, Ltd. Air-conditioner factory (72) Inventor Takashi Ogawa 1 at 60, Kutane, Iwatsuka-cho, Nakamura-ku, Nagoya

Claims (2)

[Claims] 1. A heat pump cycle comprising a compressor, a four-way valve, an outdoor heat exchanger, an expansion mechanism, and an indoor heat exchanger, and an engine driven heat pump for driving the compressor by an engine. The radiator for heat release and the outdoor heat exchanger of the heat pump are arranged so as to overlap in the direction of their air flow paths, and the ventilation direction is reversed as an outdoor air blower for blowing air to the radiator and the outdoor heat exchanger. Install what you can do,
An engine-driven heat pump, which ventilates in a direction of passing through an outdoor heat exchanger during cooling, and in a direction of passing through an outdoor heat exchanger through a radiator during heating. 2. The engine-driven heat pump according to claim 1, further comprising control means for controlling the rotation speed of the outdoor blower so that the low pressure of the refrigerant circuit becomes a set pressure during heating. Engine driven heat pump.