JP2003240364A - Refrigeration cycle unit, and heat-pump type air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent liquid compression when a compressor 2 is started after equalization, without enlarging a size of an accumulator 10. <P>SOLUTION: This unit is provided with a gas-liquid separating means 6 for a refrigerant between the first heat-exchangers 4, 8 and pressure reducing means 5, 7, an equalization circuit 20 for making gaseous refrigerant separated in the gas-liquid separating means 6 flow in a low pressure portion from an outlet side of the pressure reducing means 5, 7 to a suction side of the compressor 2, and an opening and closing means 21 for opening and closing the equalization circuit 20, and the opening and closing means 21 is opened to conduct equalization for the refrigeration cycle when an operation of the compressor 2 is stopped. The gas-liquid separating means for the refrigerant is provided in a high-pressure side by this manner, only the separated high-pressure side refrigerant separated therein is removed to a low-pressure side, and the equalization is thereby realized without increasing a liquid refrigerant amount in the low-pressure side. The liquid compression is prevented thereby when the compressor 2 is started after equalization, without enlarging the size of the accumulator 10. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration cycle device and a heat pump type air conditioner for cooling and heating a fluid such as air and water, and more particularly to a pressure equalization inside the device when the device is stopped. It is suitable to be applied to a heat pump type air conditioner for cooling and heating air by cooling and heating air.

[0002]

2. Description of the Related Art Conventionally, there is a refrigeration cycle apparatus provided with a pressure equalizing circuit for short-circuiting the high-pressure pipe and the low-pressure pipe to cancel the pressure difference in the device when the operation of the refrigeration cycle is stopped. FIG. 2 is a schematic diagram showing a configuration of a conventional heat pump type air conditioner as an embodiment of such a refrigeration cycle apparatus.

Reference numeral 2 denotes a compressor which compresses and discharges the refrigerant, and the compressed refrigerant has a four-way valve 3 which changes the direction of refrigerant flow to the heat exchanger during cooling and during heating. Reference numeral 4 is an indoor heat exchanger, 5 is an expansion valve for cooling, 6 is a receiver for separating and storing refrigerant by gas-liquid separation, 7 is an expansion valve for heating, 8 is an outdoor heat exchanger,
Reference numeral 10 is an accumulator that separates and stores the refrigerant into gas and liquid, from which the gas refrigerant is sucked into the compressor 2 and circulated.

Incidentally, 1 is an engine for driving,
Other reference numerals that are omitted correspond to the numbers given to the embodiments described later. Further, 21 is a pressure equalizing circuit that short-circuits the high pressure pipe and the low pressure pipe, 21 is an on-off valve that opens and closes the pressure equalizing circuit 20, and opens this on-off valve 21 when the operation of the refrigeration cycle is stopped. The pressure is equalized.

[0005]

However, when the pressure equalization is performed, the liquid refrigerant in the high-pressure side pipe or the like flows into the low-pressure side. Therefore, when the liquid refrigerant capacity of the accumulator is exceeded, the liquid refrigerant overflows. There is a problem that when the compressor enters the suction side of the compressor and the refrigerating cycle is started next time, the compressor sucks the liquid refrigerant to become liquid compression and cause a failure.

In particular, when the indoor heat exchanger and the outdoor heat exchanger are installed separately from each other, the amount of refrigerant to be enclosed becomes large, and it is possible to cope with this by setting an accumulator having a margin for the amount of refrigerant. Although it is possible, problems such as an increase in size of the device and an increase in cost will occur.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to provide a refrigeration cycle apparatus capable of preventing liquid compression at the time of starting the compressor after pressure equalization without increasing the size of the accumulator. It is to provide a heat pump type air conditioner.

[0008]

In order to achieve the above object, the present invention employs the following technical means. Claim 1
In the invention described in (1), the compressor (2) for compressing and discharging the refrigerant, and the first heat exchanger (4, 8) for condensing the refrigerant.
A decompression means (5, 7) for decompressing the refrigerant, a second heat exchanger (4, 8) for evaporating the refrigerant, and an accumulator (10) for gas-liquid separation and storage of the refrigerant, connected in an annular shape. In the formed refrigeration cycle apparatus, the gas-liquid separating means (6) for the refrigerant is provided between the first heat exchanger (4, 8) and the pressure reducing means (5, 7), and the gas-liquid separating means (6). And a pressure equalizing circuit (20) for circulating the separated gas refrigerant to a low pressure portion from the outlet side of the pressure reducing means (5, 7) to the suction side of the compressor (2), and a circuit inside the pressure equalizing circuit (20). An opening and closing means (21) for opening and closing the compressor is provided, and when the operation of the compressor (2) is stopped, the opening and closing means (21) is opened to equalize the pressure in the refrigeration cycle apparatus.

This is because if a gas-liquid separation portion of the refrigerant is provided on the high pressure side and only the high pressure gas refrigerant separated there is discharged to the low pressure side, pressure equalization can be performed without increasing the amount of the liquid refrigerant on the low pressure side. . This makes it possible to prevent liquid compression at the time of starting the compressor after pressure equalization without increasing the size of the accumulator.

The invention according to claim 2 is characterized in that a receiver is used as the gas-liquid separating means (6). In the first place, the present invention focuses on the fact that the receiver can be used as a liquid refrigerant reservoir in which the refrigerant is separated into gas and liquid, and the high-pressure gas refrigerant at the top of the receiver is discharged to the low pressure side to equalize the pressure in the refrigeration cycle apparatus. It can be carried out. At that time, the liquid refrigerant on the high pressure side flows into the receiver, but since the liquid refrigerant is separated into gas and liquid and is stored in the receiver, the amount of the liquid refrigerant on the low pressure side is not increased by pressure equalization.

As a result, by using the same refrigerating cycle constituent equipment as the conventional one, only the high pressure side take-out portion of the pressure equalizing circuit (20) is set as the receiver upper portion, and the compression after pressure equalization is performed without increasing the size of the accumulator. It is possible to prevent liquid compression when the machine is started.

According to a third aspect of the present invention, the refrigeration cycle apparatus according to the first or second aspect is used for a heat pump type air conditioner, and the first and second heat exchangers (4, 8) are used for indoor heat exchange. It is characterized by being used as a vessel (4) and an outdoor heat exchanger (8). This makes it possible to provide an air conditioner that does not cause liquid compression even when the compressor is started after pressure equalization without increasing the size of the accumulator.

The reference numerals in parentheses attached to the above means are as follows:
It shows a correspondence relationship with a specific means described in the embodiment described later.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing a configuration of a heat pump type air conditioner 100 according to an embodiment of the present invention. The present embodiment is driven by a water-cooled engine (for example, a diesel engine) 1, and this heat pump type air conditioner 100 is used as a stationary type or vehicle mounted type air conditioner to cool and heat the inside of a vehicle or the interior of a vehicle. However, this embodiment will be described as being applied to a stationary type.

The heat pump type air conditioner 100 is constituted by connecting refrigeration cycle equipment with refrigerant pipes, and at the time of indoor heating, the compressor 2 → the four-way valve 3 → the indoor heat exchanger 4 → the indoor unit electric valve 5 → the receiver. 6 (gas-liquid separating means) → outdoor unit motor-operated valve 7 → outdoor heat exchanger 8 → four-way valve 3 → refrigerant heater 9 → accumulator 10 → compressor 2 in order of circulation (solid arrow) for heating. .

During indoor cooling, the compressor 2 → the four-way valve 3 → the outdoor heat exchanger 8 → the outdoor unit electric valve 7 → the receiver 6 → the indoor unit electric valve 5 → the indoor heat exchanger 4 → the four-way valve 3 → the refrigerant heating The refrigerant is circulated (broken line arrow) in the order of the container 9 → the accumulator 10 → the compressor 2 for cooling.

The indoor heat exchanger 4 functions as a first heat exchanger that is a condenser during heating, and functions as a second heat exchanger that is an evaporator during cooling. In addition, the outdoor heat exchanger 8
Functions as a second heat exchanger that is an evaporator during heating, and functions as a first heat exchanger that is a condenser during cooling. Then, during heating, the outdoor unit electric valve 7 functions as an expansion valve that is a pressure reducing means for reducing the pressure of the refrigerant, and during cooling,
The indoor unit motor operated valve 5 functions as an expansion valve which is a pressure reducing means.

The engine 1 is configured to transmit a driving force to a pulley 2a provided on the compressor 2 by a V belt 1b wound around a crank pulley 1a. An electromagnetic clutch (not shown) is provided between the pulley 2a and the compressor 2 as a driving force connecting / disconnecting means that transmits or blocks the driving force transmitted to the pulley 2a to the compressor 2.

A known oil separator (not shown) for separating oil from the refrigerant discharged from the compressor 2 is provided in the refrigerant pipe connected to the discharge side of the compressor 2 (the four-way valve 3 side).
Is provided, and the oil separated by the oil separator is connected to the suction side (accumulator 10 side) of the compressor 2 via an oil return tube (not shown) in the path of the refrigerant pipe connected to the compressor 2 It is designed to be returned by the differential pressure between the front and back.

Reference numeral 110 denotes a cooling water circuit, which is a cooling water passage (not shown) formed in the main body of the engine 1 for cooling the engine 1, and a refrigerant heater 9 serving as a refrigerant heating section from the cooling water passage outlet to a cooling device. The first cooling water circuit 111 that sequentially flows through the water switching valve 113 and the cooling water pump 114 and returns to the cooling water passage inlet, and the radiator 1 from the cooling water passage outlet.
15, the second cooling water circuit 112 that sequentially flows through the cooling water switching valve 113, the cooling water pump 114, and returns to the cooling water passage inlet.
It consists of and.

Here, the cooling water pump 114 is an electric pump, and the cooling water switching valve 113 is an electromagnetic switching valve that switches between the first cooling water circuit 111 and the second cooling water circuit 112. Further, the radiator 115 is a well-known heat exchanger for exchanging heat between the cooling water and the outside air, and the refrigerant heater 9 is a double-tube heat exchanger made of, for example, metal or the like, and the cooling water and the refrigerant are heat-exchanged. It is replaceable. Further, the inlet / outlet of the cooling water passage and each member 9, 113 to 115 are connected by, for example, a rubber hose or the like.

In the heat pump type air conditioner 100 having the above construction, the indoor heat exchanger 4 and the indoor unit motorized valve 5 among the respective components constitute the indoor unit 200 and are installed at appropriate places in the room. The outdoor unit 300 is configured and installed in an appropriate place outdoors.

The heat pump type air conditioner 100
Has a control device (not shown) as a control means composed of an electronic circuit and the like. This control device includes a controller provided in a room (not shown), an outside air temperature sensor, a refrigerant temperature sensor, a water temperature sensor, etc. Enter the information, indoor unit 2
00 and the outdoor unit 300 are controlled.

Next, the structure of the main part of this embodiment will be described. A receiver 6 is provided between the indoor heat exchanger 4 and the outdoor heat exchanger 8 and the indoor unit motor-operated valve 5 and the outdoor unit motor-operated valve 7 as gas-liquid separating means for the refrigerant. Then, the gas refrigerant separated in the receiver 6 and accumulated in the upper part is reduced in pressure from the outlet side of the indoor unit electric valve 5 during cooling and the outlet side of the outdoor unit electric valve 7 during heating to the suction side of the compressor 2. A refrigerant pipe portion is provided as a pressure equalizing circuit 20 to be circulated in the portion.

In practice, the refrigerant pipe is provided between the upper surface of the receiver 6 and the downstream of the four-way valve 3 in which the refrigerant flows in the same direction during cooling and heating to the upstream of the accumulator 10 so that the liquid refrigerant can be stored. It is connected. Further, in the pressure equalizing circuit 20, a solenoid valve 21 for equalizing pressure as a circuit opening / closing means.
Is provided.

Next, the operation of this embodiment will be described based on the above configuration. The control device is a heat pump type air conditioner 1
When the electric power is supplied to 00, either the control processing during the heating operation or the control processing during the cooling operation is executed based on information from a controller (not shown).

First, the operation during the heating operation will be described. For example, when the outside air temperature is low, the heating switch of the controller (not shown) is turned on, and when the ON signal is input to the control device, the control device executes the control process during the heating operation.
The control device switches the four-way valve 3 to the heating side (solid line), starts the engine 1 and drives the compressor 2. Also,
The indoor unit motor-operated valve 5 is fully opened, and the outdoor unit motor-operated valve 7 is adjusted to an opening that functions as an expansion valve.

The high-temperature gas refrigerant discharged from the compressor 2 passes through the four-way valve 3 and is condensed in the indoor heat exchanger 4 for heating, and is then separated into gas and liquid in the receiver 6, and the liquid refrigerant is converted into the outdoor unit. The pressure is reduced by the motor-operated valve 7, evaporated by the outdoor heat exchanger 8, and the four-way valve 3
And is then heated by the refrigerant heater 9 by heat exchange with the cooling water that has recovered the engine exhaust heat, and is then gas-liquid separated by the accumulator 10 and the gas refrigerant returns to the compressor 2.

When the engine 1 is started, the cooling water pump 114 is also started, and the cooling water switching valve 113 is switched so that the cooling water flows into the first cooling water circuit 111. The cooling water pumped by the cooling water pump 114 flows through the cooling water passage in the engine 1 to absorb the engine exhaust heat, and then enters the refrigerant heater 9, where the cooling water is evaporated with the refrigerant in the outdoor heat exchanger 8. Heat exchange to heat the refrigerant. After that, the cooling water switching valve 113 returns to the cooling water pump 114 and is sent again to the cooling water passage in the engine 1.

Since the cooling water circulates in this way, the exhaust heat of the engine 1 is recovered by the cooling water and used for heating the refrigerant by the refrigerant heater 9 to form a part of the heating heat source of the heat pump type air conditioner 100. Becomes

Next, the operation during the cooling operation will be described. For example, when the outside air temperature is high, the cooling switch of the controller (not shown) is turned on, and when an ON signal is input to the control device, the control device executes the control process during the cooling operation.
The control device switches the four-way valve 3 to the cooling side (broken line), starts the engine 1 and drives the compressor 2. Further, the outdoor unit motor-operated valve 7 is fully opened, and the indoor unit motor-operated valve 5 is adjusted to an opening degree that functions as an expansion valve.

The high-temperature gas refrigerant leaving the compressor 2 passes through the four-way valve 3, is condensed in the outdoor heat exchanger 8, is separated into gas and liquid by the receiver 6, and the liquid refrigerant is decompressed by the indoor unit electric valve 5, After cooling by evaporating in the outdoor heat exchanger 8, the four-way valve 3
Through the refrigerant heater 9 to the accumulator 10, where the gas-liquid separation is performed in the accumulator 10 and the gas refrigerant returns to the compressor 2.

When the engine 1 is started, the cooling water pump 114 is also started, and the cooling water switching valve 113 is switched to the direction in which the cooling water flows into the second cooling water circuit 112. The cooling water pumped by the cooling water pump 114 flows through the cooling water passage in the engine 1, absorbs the exhaust heat of the engine, and then enters the radiator 115. After that, the cooling water switching valve 1
It returns from 13 to the cooling water pump 114 and is sent again to the cooling water passage in the engine 1.

Since the cooling water circulates in this manner, the exhaust heat of the engine 1 is recovered by the cooling water, and the radiator 115 exchanges heat with the outside air to radiate the heat. With the above configuration and operation, when the engine 1 is stopped or the driving force is cut off by the electromagnetic clutch, the compressor 2 is stopped and the refrigerant circulation in the refrigeration cycle is stopped. 21
Is opened to equalize the pressure in the refrigeration cycle apparatus.

As described above, the gas-liquid separating means 6 for the refrigerant is provided on the high pressure side, and only the high pressure gas refrigerant separated there is discharged to the low pressure side, so that the pressure equalization is performed without increasing the amount of the liquid refrigerant on the low pressure side. ing. As a result, it is possible to prevent liquid compression at the time of starting the compressor 2 after pressure equalization without increasing the size of the accumulator 10.

A receiver is used as the gas-liquid separating means 6. With this, by using the same refrigeration cycle constituent device as the conventional one, only the high pressure side take-out portion of the pressure equalizing circuit 20 is used as the receiver upper portion, and the liquid at the time of starting the compressor after pressure equalization without increasing the size of the accumulator. Compression can be prevented.

Further, such a pressure equalizing circuit 20 is used in a heat pump type air conditioner in which the first and second heat exchangers are the indoor heat exchanger 4 and the outdoor heat exchanger 8. This makes it possible to provide an air conditioner that does not cause liquid compression even when the compressor 2 is started after pressure equalization without increasing the size of the accumulator 10.

(Other Embodiments) In the above embodiment,
Although a receiver is used as the gas-liquid separation means 6, the present invention is not limited to this, and may be provided as a gas-liquid separation device dedicated to the pressure equalizing circuit 20. Further, although the engine-driven heat pump type air conditioner is used, it may be applied to a refrigerant compression type refrigeration cycle other than the heat pump type air conditioner. Further, the compressor 2 may be something other than an engine driven one such as an electric compressor, or may be applied to a hot water supply device or the like for heating brine (heat exchange medium) such as water or antifreeze.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of a heat pump type air conditioner according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a configuration of a heat pump type air conditioner according to a conventional embodiment.

[Explanation of symbols]

2 Compressor 4 Indoor heat exchanger (first heat exchanger during heating, second heat exchanger during cooling) 5 Indoor unit electric valve (pressure reducing means during cooling) 6 Receiver (gas-liquid separation means) 7 Outdoor unit Motor operated valve (pressure reducing means during heating) 8 Outdoor heat exchanger (first heat exchanger during cooling, second heat exchanger during heating) 10 Accumulator 30 Pressure equalizing circuit 31 Pressure equalizing solenoid valve (opening / closing means)

Claims (3)

[Claims] 1. A compressor (2) for compressing and discharging a refrigerant.
A first heat exchanger (4, 8) for condensing the refrigerant, a decompression means (5, 7) for decompressing the refrigerant, a second heat exchanger (4, 8) for evaporating the refrigerant, Accumulator (1) that separates and stores the refrigerant by gas-liquid separation
0) in a refrigeration cycle apparatus formed by connecting the first heat exchanger (4, 8) and the pressure reducing means (5, 7).
And a gas-liquid separating means (6) for the refrigerant, and the gas refrigerant separated by the gas-liquid separating means (6) is sucked into the compressor (2) from the outlet side of the pressure reducing means (5, 7). Pressure equalizing circuit (20) that circulates in the low pressure portion up to the side, and opening / closing means (2) that opens and closes the circuit within the pressure equalizing circuit (20).
1) is provided, and when the operation of the compressor (2) is stopped, the opening / closing means (21) is opened to equalize the pressure in the refrigeration cycle apparatus. 2. The refrigeration cycle apparatus according to claim 1, wherein a receiver is used as the gas-liquid separating means (6). 3. The refrigeration cycle apparatus according to claim 1 or 2, comprising the first and second heat exchangers (4, 8).
Is a heat pump type air conditioner characterized by being an indoor heat exchanger (4) and an outdoor heat exchanger (8).