JPS60259794A - Heat pump type air conditioner - Google Patents

Abstract

PURPOSE:To make the overheat of a compressor and a supercompression phenomenon preventable from occurring, by installing a valve, which interconnects a discharge chamber in time of pressure in a displacement chamber being high but interconnects a liquid injection circuit in time of this pressure being low, in a minimum displacement chamber of a scroll compressor. CONSTITUTION:In a hole 20 to be interconnected to an actuating chamber 9, becoming minimum displacement volume, of a scroll compressor, there is provided with a selector valve 20 serving both as a liquid injection valve and a relief valve. The back of this selector valve 20 is interconnected to a liquid injection pipe 107, and it is so constituted as to make a valve body 23 move up and down with a pressure differential between injection pressure and pressure inside the actuating chamber. When the valve body moves up and down with the injection pressure, a liquid refrigerant is spouted to the inside of the actuating chamber via an orifice 27 but when the inside of the actuating chamber comes into a state of supercompressed, the valve body moves upward whereby the pressure inside the actuating chamber is relieved to a discharge chamber via a passage 26.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a heat pump type air conditioner using a scroll compressor, and particularly to a heat pump type air conditioner suitable for obtaining high temperature air or high temperature water.

[Background of the invention]

A conventional heat pump air conditioner using a scroll compressor will be explained with reference to FIGS. 5 and 6. Figure 5 is a cycle system diagram of a heat pump type air conditioner and a vertical cross-sectional view of a scroll compressor, Figure 6 (al is a vertical cross-sectional view of the compressor section of the scroll compressor, and Figure 6 (bl is a cross-sectional view thereof) In the figure, 100 is a scroll compressor;
101 is a four-way valve, 102 is 'l & Kaisho Go-25979
4(2) The first heat exchanger, 103 is an expansion valve, and 104 is a second heat exchanger. Each of these devices is connected to piping as shown in the figure, and a heat pump cycle is constructed by switching the four-way valve 101 to the solid line position or the broken line position to flow the refrigerant in the direction of the solid line arrow or the broken line arrow.

To explain the structure of the scroll compressor 100 in detail, a compressor section 2 and an electric motor 3 are housed in a closed container l. A compression chamber 9 is formed in the compressor section 2 by a fixed scroll 5 and an orbiting scroll 6, and the compression chamber 9 is It gradually moves towards the center and its volume decreases, compressing the gas. The rotation of the orbiting scroll is prevented by an Oldham mechanism 13 consisting of an Oldham ring, a key, and a key provided on the back surface of the orbiting scroll. An intermediate pressure chamber 15 is provided on the back surface of the orbiting scroll, and communicates with the compression chamber through a small hole (not shown) provided in the orbiting scroll end plate.

The pressure in the intermediate pressure chamber 15 is approximately equal to the average pressure of the compression chamber through which the small hole communicates, and the position of the small hole is adjusted so that this pressure is the appropriate pressure necessary for tightly contacting the orbiting scroll with the fixed scroll. is decided. The bearings and the sliding surfaces of the orbiting scroll head plate are lubricated by supplying oil from the oil reservoir 16 through oil passages 17, 18, and 19 by differential pressure or centrifugal pump action. Gas flows from suction pipe 7 to suction chamber 8
The gas is compressed and discharged from the discharge boat 10 into the closed container 1, passes through the discharge gas passage 11, and is discharged from the discharge pipe 12 to the outside of the compressor.

By the way, in the scroll compressor 100,
When the operating temperature of the heat pump cycle is high, the discharge pressure rises and the discharge gas temperature also rises, which may cause the motor winding temperature to exceed the limit value and cause burnout, or the oil temperature to rise and lubricate the bearings. There are problems such as negative effects and deterioration of the oil itself.

Further, as shown in FIG. 6, the compression chambers 9a and 9b complete suction and form the maximum sealed volume Vs as the orbiting scroll 6 moves, and the compression chamber gradually moves toward the center and decreases in volume. However, until the minimum sealed volume Vi shown in 9c and 9d on page 6 is formed, the suction pressure P is maintained regardless of the discharge pressure determined by the operating state of the refrigeration cycle.
The compression chamber pressure Pc is determined from s, the compression chamber volume Vc, and the polytropic index n as follows.

s n Pc = Ps () c Furthermore, the pressure Pi when the minimum sealed volume Vi is formed immediately before communicating with the discharge boat 10 in the center is also determined as follows.

Pi = Ps (-M-L-)'' ■1 After this, when the compression chamber communicates with the discharge boat IO, the pressure becomes the discharge pressure Pd.

When Pd matches Pi, the pressure follows the line 1 → 2 → 3 → in the pressure-volume diagram in Figure 7, and no compression power loss occurs, but if Pd is lower than Pi, the pressure decreases to 1. →2→2
Following the line '→3', overcompression occurs and a compression power loss corresponding to the area shown by hatching in the figure occurs. On the other hand, if Pd is higher than Pi, the pressure will follow the line 1 → 2 → 2' → 3', resulting in insufficient compression and a compression power loss corresponding to the area shown by the hatching in Figure B on page 7. arise. As described above, the scroll compressor has the disadvantage that efficiency decreases when it is operated at a pressure ratio other than the design pressure ratio Pi/Ps.

On the other hand, when an air conditioner is cooling or heating, the suction pressure and discharge pressure fluctuate due to changes in temperature inside and outside the valve chamber, and the pressure also changes.

In particular, in the case of high-temperature heat pump air conditioners designed to obtain high-temperature air or high-temperature water, the pressure ratio P d / P during cooling is
While s is 3 to 35, the pressure ratio during heating and hot water supply is 55 to 10, which is a wide range of pressure ratios. If the aforementioned scroll compressor is used in an air conditioner that requires such a wide pressure ratio range, the energy efficiency ratio (SEER) throughout the year will be considerably lower than the energy efficiency ratio (EER) during optimum pressure ratio operation. There is a problem with doing so.

As mentioned above, in conventional heat pump air conditioners, when the scroll compressor is designed with a high pressure ratio, efficiency is good during operation with a high pressure ratio such as during high-temperature wind heating or high-temperature water supply, but the discharge gas temperature '1% Kaisho GO-25979
4(3) Excessive rise is a problem, and during operation at a low pressure ratio such as during cooling, the temperature of the discharged gas is low and there is no problem, but the problem arises that the efficiency decreases.

In addition, the suction pressure is high at startup, and in scroll compressors with a high pressure ratio design, a very large overcompression phenomenon occurs and the startup torque becomes extremely large, leading to insufficient motor torque and excessive startup current flowing. There are also problems such as a shortage of power supply capacity.

[Purpose of the invention]

The purpose of the present invention is to prevent excessive rise in discharge gas temperature during high pressure ratio operation, prevent overcompression phenomenon during low pressure ratio operation and startup, and achieve high reliability and efficiency under a wide range of conditions. An object of the present invention is to provide a heat pump type air conditioner that can be operated.

[Summary of the invention]

In order to achieve this object, the present invention provides a heat pump cycle with a liquid refrigerant injection circuit connected to the outlet side of the first and second heat exchangers, respectively, when the first and second heat exchangers act as condensers, and The compression chamber portion 9, which has the smallest volume in the compressor, is provided with a valve device that operates based on the differential pressure between the pressure of the compression chamber and the high pressure circuit pressure of the heat pump cycle, so that the pressure inside the compression chamber is equal to the high pressure circuit pressure of the heat pump cycle. When the pressure is low, the compression chamber and the liquid refrigerant injection circuit are communicated via the valve device, and when the pressure inside the compression chamber is higher than the high pressure circuit pressure of the heat pump cycle, the compression chamber and the discharge port are communicated via the valve device. It is characterized by being configured so that it communicates with the side.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. Fig. 1 is a cycle system diagram of a heat pump air conditioner according to the present invention and a vertical cross-sectional view of a scroll compressor, Fig. 2 is a cross-sectional view of a compressor section of the scroll compressor, and Fig. 3 is a diagram showing the compressor section and valves of the scroll compressor. FIG. 4 is a cross-sectional perspective view of the device, and FIG. 4 is a cross-sectional perspective view showing the operating state of the valve device. In FIG. 1, a scroll compressor 100, a four-way valve 101, a first heat exchanger 102, an expansion valve 103, and a second heat exchanger 10 are shown.
By connecting 4 with piping as shown in the figure, the heat pump size 10? Dingkuru is composed. Furthermore, the solid arrow indicates the four-way valve 101.
indicates the flow direction of the refrigerant when the four-way valve 101 is switched to the solid line position, and the broken line arrow indicates the flow direction of the refrigerant when the four-way valve 101 is switched to the broken line position. Furthermore, since the basic configuration of the scroll compressor is the same as that shown in FIG. 5, the same or corresponding parts are given the same reference numerals.
The explanation will be omitted.

The heat pump cycle includes a connection between the first heat exchanger 102 and the expansion valve 103, and between the second heat exchanger 104 and the expansion valve 1.
03 through check valves 105 and 106, respectively, are provided with liquid refrigerant injection circuits 107. The check valves 105 and 106 allow the refrigerant to flow only in the direction of the arrow.

In the compression chamber 9 portion having the minimum volume in the scroll compressor 100, there is a valve device 20.20 that operates based on the differential pressure between the pressure of the compression chamber 9 and the high pressure circuit pressure of the heat pump cycle.
is installed. As shown in FIG. 3, the valve device 20 has a valve body 21 mounted on the end plate of the fixed scroll 5
and a valve body 23 housed in a valve chamber 22 within the valve body 21. The lower part of the valve chamber 22 communicates with the compression chamber 9 through a first boat 24 bored in the head plate, and the upper part communicates with the compression chamber 9 through a second boat 25 bored in the valve seat portion of the valve body 21. A third boat 2 is connected to the refrigerant injection circuit 107 and is bored halfway through the valve body 21 and the end plate.
It communicates with the discharge boat 10 via 6. The valve body 2
No. 3 has pressure-receiving surfaces formed on its upper and lower surfaces, and has a flow path n opening to both pressure-receiving surfaces inside. The lower open end of the flow path 27 is located at the center of the valve body 23, and the upper open end is located offset from the center of the valve body 23 by a distance equal to or greater than the radius of the second boat 25.

In the above-mentioned valve device, when the pressure acting on the upper pressure receiving surface of the valve body 23 is higher than the pressure acting on the lower pressure receiving surface, the valve body 23 is lowered by the differential pressure and the 17th
-124 and the third boat 26 are closed, and the inside of the compression chamber 9 and the liquid refrigerant injection circuit 107 are communicated via the flow path 27 in the valve body 23. In addition, the pressure acting on the upper pressure receiving surface of the valve body 23 is applied to the lower pressure receiving surface.
4) When the pressure is lower than the applied pressure, the valve body 23 is raised by the pressure difference and closes the second port 25, and at the same time opens the first boat 24 and the third boat 26 to open the inside of the compression chamber 9. and the discharge boat 10, both of the aforementioned boats 24.27
It is designed to communicate via.

In this embodiment, as shown in FIG. 2, the first boat 24 is placed in a position that is almost in contact with the lap wall surface, and the first boat 24 and the discharge boat 1
0 is shown in the example in which it is provided in a position where it communicates with the same compression chamber, but this position is the most efficient in terms of efficiency, and it does not preclude it from being provided in any other position.

Next, the operation of the present invention will be explained.

When operating at a pressure ratio higher than the design pressure ratio, the pressure on the high pressure side of the heat pump cycle is lower than the pressure in the compression chamber 9.
That is, since the pressure of the liquid refrigerant injection circuit 107 connected to the outlet of the first heat exchanger 102 or the second heat exchanger 104 acting as a condenser is higher, the valve device 20
The valve body 23 is lowered as shown in FIG. As a result, the first boat 24 and the thirteenth page third boat 26 are closed, and the compression chamber 9 and the discharge boat 1o are cut off. At this time, the liquid refrigerant injection circuit 107 and the compression chamber 9 communicate with each other via the flow path n of the valve body 23, and as shown by arrow A, the liquid refrigerant is injected into the compression chamber 9, depressurized, vaporized, and compressed. The gas temperature in chamber 9 is lowered. Therefore, the temperature of the discharged gas also decreases, and an excessive increase is prevented.

On the other hand, when operating at a pressure ratio lower than the design pressure ratio and at startup, the high-pressure side pressure of the heat pump cycle,
That is, the pressure in the compression chamber 9 becomes higher than the pressure in the liquid refrigerant injection circuit 107 connected to the condenser outlet, and the valve body 23 of the valve device 2o is raised as shown in FIG. At this time, the second port 25 is closed, and the compression chamber 9 and the liquid refrigerant injection circuit 107 are cut off. Further, at this time, the compression chamber 9 and the discharge boat LO communicate with each other via the first boat 24 and the third boat 26, and the gas in the compression chamber 9 is released to the discharge boat LO side as shown by the arrow port. Therefore,
Overcompression is prevented, efficiency is improved during low pressure ratio operation, and excessive torque and excessive current can be prevented during startup.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to prevent excessive rise in discharge gas temperature during high pressure ratio operation, and prevent overcompression phenomenon during low pressure ratio operation and startup, thereby increasing reliability. Moreover, it can operate efficiently under a wide range of conditions.

[Brief explanation of the drawing]

1 to 4 show an embodiment of the present invention, FIG. 1 is a cycle system diagram of a heat pump air conditioner according to the present invention and a longitudinal sectional view of a scroll compressor, and FIG. 2 is a compression diagram of a scroll compressor. 3 is a cross-sectional perspective view of the compressor unit and valve device, FIG. 4 is a sectional perspective view showing the operating state of the valve device, and FIG. 5 is a cycle of a conventional heat pump air conditioner. System diagram and vertical cross-sectional view of scroll compressor,
FIG. 6(a) is a longitudinal cross-sectional view of the compressor section of the scroll compressor, Tb) is a cross-sectional view thereof, and FIG. 7 is a pressure-volume diagram. 5. Fixed scroll, 6. Rotating scroll,
9l5 100... Compression chamber, 10... Discharge boat, 20... Valve device, 21... Valve body, 22... Valve chamber, 23... Valve body, 24... First boat , 25... 2nd boat, 2
6... Third port, 27... Channel, 100... Scroll compressor, 101... Four-way valve, 102... First heat exchanger, 103... Expansion valve, 104... -Second heat exchanger, 107...liquid refrigerant injection circuit. Agent Patent Attorney Tadashi Akimoto Jitsu No. 1 Law No. 2 Illustration 3 Ko No. 4 107 Fig. 5 Fig. 6 'P, 7 Fig. 6 藷V

Claims (1)

[Claims] 1. A heat pump cycle is configured by connecting a compressor, a four-way valve, a first heat exchanger, an expansion valve, and a second heat exchanger with piping,
The compressor includes a fixed scroll member and an orbiting scroll member each having a spiral wrap standing upright on an end plate, and both scroll members are assembled with the wraps facing inward. In a heat pump air conditioner that uses a scroll compressor that compresses refrigerant by rotating the refrigerant without rotating,
The heat pump cycle is provided with a liquid refrigerant injection circuit connected to the outlet side of the condenser when the first and second heat exchangers act as a condenser, and a compression chamber having a minimum sealed volume in the scroll compressor is provided. A valve device operated by a pressure difference between the pressure in the compression chamber and the high pressure circuit pressure of the heat pump cycle is provided in a position communicating with
When the pressure in the compression chamber is higher than the high pressure circuit pressure of the heat pump cycle, the compression chamber and the liquid refrigerant injection circuit are communicated via the valve device, and when the pressure in the compression chamber is higher than the high pressure circuit pressure of the heat pump cycle, the compression chamber and the discharge boat are communicated via the valve device. A heat pump type air conditioner characterized by being configured to communicate with the side. 2. The valve device includes a valve body mounted on an end plate of a fixed scroll member, and a valve body housed in a valve chamber in the valve body, and one of the valve chambers has a first hole bored in the end plate. The second boat communicates with the compression chamber via a boat, and the other communicates with the liquid refrigerant injection circuit via a second boat provided in the valve seat portion of the valve body, and a hole is bored halfway through the valve body and end plate. It communicates with the discharge boat through a third port, pressure receiving surfaces are formed on both sides of the valve body, and a flow path opening to both pressure receiving surfaces is provided inside, so that the pressure in the compression chamber is controlled by the heat pump cycle. When the pressure is lower than the high pressure circuit pressure, the pressure difference causes the valve body to be displaced to the position where the first boat is closed, thereby communicating the compression chamber and the liquid refrigerant injection circuit via the flow path, and When the pressure inside the compression chamber becomes higher than the high pressure circuit pressure of the heat pump cycle, the pressure difference causes the valve body to be displaced to a position that closes the second boat, thereby connecting the compression chamber and the discharge boat via the third boat. A heat pump type air conditioner according to item 1 of the patent application, characterized in that the heat pump type air conditioner is configured to communicate with each other.