JPS61161371A - Heat pump type refrigerator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

(a) Industrial Application Field The present invention relates to a heat pump type refrigeration system, and particularly to a heat pump type refrigeration system suitable for heating and cooling a plurality of rooms. (Part 1) Conventional technology In a heat pump type refrigeration system that can operate multiple indoor units for heating and cooling simultaneously or arbitrarily, if any indoor unit stops operating, especially during heating, the amount of refrigerant condensed decreases and the high-pressure side pipe As the pressure rises abnormally and overloads the compressor, there is a risk that the protection device will be activated and heating will no longer be possible.Therefore, as a countermeasure, the In addition, attempts have been made to control the capacity of the compressor according to changes in the indoor load, and to bypass the pressure gas to the low pressure side when the high pressure increases. When the compressor is busy with large load fluctuations, such as a large separate air conditioner with three or more connected units, the compressor capacity cannot be adjusted to keep up with the load, and high pressure control cannot be performed accurately. , the low-pressure pressure increases due to the bypass of the high-pressure saturated gas, the temperature of the compressor increases, and the windings burn out. e] Problems to be solved by the invention The problems to be solved by the invention are The purpose is to suppress the increase in high pressure without adversely affecting the compressor, so that an appropriate refrigerant pressure can be obtained regardless of increases or decreases in the heating load.Measures to solve the problem According to the present invention, during heating, the above problem is solved by distributing the refrigerant to the discharge port of the compressor, the gas pipe, the indoor heat exchanger, the liquid pipe, the outdoor heat exchanger, the auxiliary evaporator, and the compressor suction port in this order. During cooling, the refrigerant is sent to the compressor discharge port, outdoor heat exchanger, liquid pipe,
In a heat pump type refrigeration system that flows in the order of indoor heat exchanger, gas pipe, auxiliary evaporator, and compressor inlet, a portion of the refrigerant in the liquid pipe is supplied to the auxiliary evaporator via the first on-off valve and the pressure reducing device. a first bypass circuit that supplies a portion of the refrigerant discharged from the compressor to the outdoor heat exchanger via a second on-off valve; This problem is solved by providing a control device that opens the $2 on-off valve and opens the $2 on-off valve when the high pressure is high. (E) When the heating load on the indoor side becomes smaller during heating, the amount of refrigerant condensed in the indoor heat exchanger decreases, resulting in an excess of refrigerant and an increase in high pressure. Then, when the first on-off valve is opened, a part of the refrigerant in the liquid pipe flows through the first bypass circuit, is depressurized by the pressure reducing device, and then evaporated by the auxiliary evaporator. Therefore, the amount of liquid refrigerant flowing into the outdoor heat exchanger decreases, and the low pressure decreases, which in turn causes the high pressure to decrease. Despite such refrigerant control, if the high pressure increases, the second on-off valve is opened. Then, a part of the high-pressure saturated gas (hot gas) discharged from the compressor is supplied to the outdoor heat exchanger through the second bypass circuit, and an increase in the high-pressure pressure is suppressed. In this way, rather than supplying hot gas directly to the low-pressure side (by supplying hot gas to the outdoor heat exchanger), the rise in low-pressure pressure is reduced and the temperature rise of the compressor is prevented. (To) Examples Below, the present invention will be explained in detail as shown in the drawings.(1) has a machine room (2) in the lower part and a heat exchange room (3) in the upper part.
(4a), (4b), and (4c) are indoor units, which are equipped with a gas pipe (5) and a liquid pipe (
6) is connected with

[There is. (7) is a compressor, (8) is a four-way switching valve for switching between cooling and heating channels, and (9a) (9b) (9c) are gas side branch pipes <5a) (
5b) Installed on (5c)
10a) (10b) (10C) are indoor heat exchangers that forcibly exchange heat with indoor air and indoor fans (lla) (llb) (llc), respectively, (12a) (12b) (1
2c) is a cooling pressure reducing element consisting of an expansion valve; (14a)
(14b) (14c) are heating check valves, (15a) (1
5b) (15c) are liquid side branch pipes (6a) (6b) (6C
) is an electromagnetic liquid side on-off valve (161 is the liquid receiver, α
η is a pressure reducing element for heating consisting of an expansion valve, 0 seconds is a check valve for cooling, 顛α9 is an outdoor heat exchanger that forcibly exchanges heat between outdoor air and an outdoor fan ■, 021) is a compressor (7 ) is an auxiliary evaporator that cools the heat that rises due to heat generation and is trapped in the machine room (2).■ is an accumulator. @During heating operation, a portion of the high-pressure liquid refrigerant in the liquid receiver ae is transferred to the auxiliary evaporator a! via the auxiliary pressure reducing element (c) consisting of the first electromagnetic on-off valve @ and the capillary tube. The first bypass circuit (a) leads to the outdoor heat exchanger (II) through a second electromagnetic on-off valve and a part of the high-pressure saturated gas (hot gas) discharged from the compressor (7). (1! 2nd lead to 3
It is a bypass circuit. ■ is the gas side on/off valve (
9a) (9b) (9c) and liquid side on-off valve (15a) (
15b) and (15c), and K controls the rotation speed of the compressor (7) depending on the number of operating indoor units. 1 Opening the on-off valve @ and
Compressor (7) discharge pipe Ci! This is a control device that controls opening and closing of the second on-off valve □□□ according to a detection signal from a pressure detector (to) provided at 9. Next, the circuit operation will be explained. Indoor - 2) (4a) (4
b) When three units (4c) are in heating operation at the same time, the four-way switching valve (8) is in the solid line state, and the gas side on-off valve (9a) is in the solid line state.
(9b) (9c) and light side on-off valves (15a) (15b
) (15c) is opened, and the compressor (7) operates at full speed (for example, 1800 rpm). The high-temperature, high-pressure gas refrigerant discharged from the discharge port (7a) of the compressor (7) passes through the four-way switching valve (8) - gas side on-off valves (9a) (9b) (9c) -
Indoor heat exchanger (10a) (10b) (10c) - Heating check valve (14a) (14b') (14c) - Light side on-off valve (15a) (15b) (15c), - Receiver ae - Heating pressure reducing element 17) - Outdoor heat exchanger α9αl - Four-way switching valve (8) - Auxiliary evaporator 01) - Accumulator are valved in sequence and returned to the suction port (7b) of the compressor (7) . With this operation, the indoor heat exchanger (10a) (10
b) The indoor unit due to the refrigerant condensation action in (10c))
Each room with (4a), (4b, and 4c) is heated, and the outdoor heat exchanger α9 (19
The auxiliary evaporator (2) draws this heating heat source from outside air and the warm air inside the machine room (2). As a result of this heating operation, the indoor temperature rises and the room temperature thermostat is turned off, or the manual switch is turned off and, for example, when the indoor fan (lie) of the indoor unit (4c) stops, heating operation of only one unit stops. Refrigerant condensation is no longer performed in the indoor heat exchanger (10c). At this time,
The control device (to) is an indoor unit whose operation is stopped) (4c)
Close the gas side on-off valve (9C) and the light side on-off valve (15c), and further increase the rotation speed of the compressor (7) to 1400 r*p.
Lower it to @m. In this way, during heating operation, while the indoor unit (4c) is stopped, the gas side on-off valve (9C) and the light side on-off valve (15c) are closed, and the compressor (7) operates at medium speed. K, the high pressure is maintained within an appropriate range of 15 kg/ffl to zolq/c++t without the compressor (7) rising to an abnormal temperature K. This heating operation control is the same even when the other indoor units (4a) and (4b) are stopped. Next, we will explain what will happen if, for example, two indoor units (4b) and (4c) stop heating operation. In such a case, both units) (4b) (4c) gas side on-off valve (9b)
(9c) and the light side on-off valve (15b) (tsc) are closed, and the control device (to) operates the compressor (7) at 1000 r
*p*m low-speed operation is busy, and the first on-off valve (Foundation)
to be opened. In this way, when the number of operating indoor units decreases from three to one, the compressor (7) rotates at the lowest rotation speed (1000r@p
Operate with @m). However, because it is mechanically impossible to reduce the rotation speed to 1/3 of the maximum rotation speed to match the reduction in the amount of refrigerant condensation, the amount of refrigerant circulating becomes excessive, and the liquid refrigerant condenses in the indoor heat exchanger (10a). is evaporated and superheated in the large-capacity outdoor heat exchanger (11 (II), and this increase in the degree of superheating causes the discharge pressure of the compressor (7) to rise. When you open the
A portion of the liquid refrigerant that accumulated at the time of the liquid receiver flows through the first bypass circuit (
After being depressurized by the auxiliary pressure reducing element (c), it is evaporated by the auxiliary evaporator CI) and sucked into the compressor (7). This flow of refrigerant causes the outdoor heat exchanger (19 (
The amount of liquid refrigerant flowing into the refrigerant 19 decreases, the amount of superheated refrigerant decreases, the low pressure decreases, and the increase in high pressure is suppressed. In addition, despite such refrigerant control, if the high pressure exceeds 23 kg/d for some reason, the control device
opens the second on-off valve and supplies hot gas to the outdoor heat exchanger α9r11 via the second bypass circuit (e). Therefore, the discharge pressure of the compressor (7) decreases. Moreover, since hot gas is not directly supplied to the suction side of the compressor (7), there is little rise in low pressure and there is no concern that the temperature of the compressor (7) will rise. As a result, the high pressure increases from 22 to 9
When the temperature drops below A, the second on-off valve (■) closes. On the other hand, during cooling operation, when the four-way switching valve (8) is switched to the broken line state and the compressor (7) is operated at high speed, the compressor (7) -
Four-way switching valve (8) - Outdoor heat exchanger αIα - Cooling check valve a8 - Receiver tilting liquid side on-off valve (15a) (15b)
(15C)-Reducing pressure element for cooling (12a) (12b) (1
2c) - Indoor heat exchanger (10a) (10b) (10c
) - Gas side on-off valve (9a) (9b) (9c) - Four-way switching valve (8) - Auxiliary evaporator Vessel (10m)
Each room is cooled by the refrigerant evaporation action in (10b) and (10c). For example, when only one of the indoor units (4c) stops cooling operation, the light side on-off valve (15c) and the gas side on-off valve (9c) close, and the compressor (7) operates at medium speed. Cooling operation is performed with a refrigerant circulation amount suitable for two-unit operation. Furthermore, for example, if the cooling operation of the indoor unit (4b) is also stopped, the light side on-off valve (15b) and the gas side on-off valve (9)
b) is closed, and the compressor (7) operates at low speed. During cooling operation, even if one or two indoor units stop operating, the outdoor heat exchanger (I9 (1'J) sufficiently condenses the refrigerant, so the high pressure will not rise. In the embodiment described above, a plurality of indoor heat exchangers (1
0a), (10b), and (10c) are connected in parallel to cool and heat multiple rooms. K is also applicable. (g) Effects of the Invention Since this invention is configured as described above, when the heating load decreases and refrigerant becomes excessive, part of the refrigerant in the liquid pipe is depressurized in the @1 bypass circuit and auxiliary The refrigerant can be evaporated in the evaporator and then sucked into the compressor, thereby reducing the amount of refrigerant flowing into the outdoor heat exchanger and preventing a rise in high pressure. Moreover, in the event that the high pressure rises, the discharge gas from the compressor is supplied to the outdoor heat exchanger, which prevents the low pressure from rising and burns out the windings due to the compressor's temperature rise. It is possible to suppress high pressure while preventing this.

[Brief explanation of the drawing]

The figure is a piping system diagram of a heat pump type refrigeration system showing one embodiment of the present invention. (5)...Gas pipe, (6)...Liquid pipe, (7)...
...Compressor, (10a) (10b) (10c) -Indoor heat exchanger, (19-...Outdoor heat exchanger, (21)
)...Auxiliary evaporator, @...1st bypass circuit,
(Foundation)...First on-off valve, (C)...Pressure reducing device, Kan...Second bypass circuit, ■...Second on-off valve, (To)...Control device.

Claims (3)

[Claims] (1) During heating, the refrigerant flows through the compressor discharge port, gas pipe, indoor heat exchanger, liquid pipe, outdoor heat exchanger, auxiliary evaporator, and compressor inlet in this order, and during cooling, the refrigerant flows through the Compressor discharge port, outdoor heat exchanger, liquid pipe, indoor heat exchanger, gas pipe,
In a heat pump refrigeration system in which refrigerant flows in order from an auxiliary evaporator to an inlet of a compressor, a first bypass circuit supplies part of the refrigerant in a liquid pipe to the auxiliary evaporator via a first on-off valve and a pressure reducing device, and a compressor. A second bypass circuit supplies a part of the refrigerant discharged from the refrigerant to the outdoor heat exchanger via a second on-off valve, and opens the first on-off valve when the heating load is small and when the high pressure is high. A heat pump type refrigeration device comprising: a control device for opening a second on-off valve. (2) The heat pump type refrigeration system according to claim 1, wherein a plurality of indoor heat exchangers are provided in parallel. (3) A heat pump type refrigeration system according to claim 1 or 2, wherein the compressor is of a variable capacity type.