KR20060104931A - Engine driving type air conditioner - Google Patents

Abstract

The present invention relates to an engine driven air conditioner that can quickly determine the amount of refrigerant supplied to a supercooled heat exchanger and stabilize the system quickly.

The bypass for heat exchange in the subcooling heat exchanger 213 branched from the part located upstream of the subcooling heat exchanger 213. In addition, the degree of subcooling of the refrigerant at the outlet of the outdoor heat exchanger 204 was determined, and the subcooling expansion valve 216 was opened and closed based on the degree of subcooling.

Description

Engine Driven Air Conditioner {ENGINE DRIVING TYPE AIR CONDITIONER}

1 is a schematic configuration diagram of an engine driven air conditioner according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

100: engine driven air conditioner 200: outdoor unit

300: indoor unit 201: engine

202: compressor (compressor) 202a: suction port

202b: discharge port 203: four-way switching valve

204: outdoor heat exchanger 205: refrigerant-cooling water heat exchanger

206: accumulator 207: main circuit

207a: outdoor side first passage 207b: outdoor side second passage

207c: third outdoor passage 207d: fourth outdoor passage

207e: outdoor side fifth passage 207f: cooling passage

208: bypass passage for low temperature heating 209: main solenoid expansion valve

210: sub solenoid expansion valve 212: control means

213: supercooled heat exchanger 214: bypass passage for supercooling

215: fan 216: supercooled expansion valve

217: temperature sensor 218: supercooling temperature sensor

219: pressure sensor 220: supercooled expansion valve control means

301: main circuit 301b: indoor side first passage

301c: Interior side second passage 301d: Interior side third passage

302: indoor heat exchanger 303: expansion valve

Patent Document 1. Japanese Unexamined Patent Application Publication No. 10-160267

Patent Document 2. Japanese Unexamined Patent Publication No. 2002-39648

The present invention relates to an engine driven air conditioner.

GHP (Gas Heat Pump) is a kind of air conditioner, and performs air conditioning using a gas engine. Specifically, the refrigerant is circulated in the main circuit by driving a compressor (compressor) connected to the main circuit through which the refrigerant flows, and condensation and evaporation of the refrigerant in the indoor heat exchanger and the outdoor heat exchanger installed in the main circuit. By performing the operation, air conditioning is performed by the movement of heat accompanying this operation.

In detail, during the heating, the refrigerant discharged from the compressor passes through the indoor heat exchanger (condensation), expansion valve (expansion), and outdoor heat exchanger (evaporation) through the main circuit in this order to return to the compressor. When the indoor heat exchanger condenses the refrigerant, heat of condensation is generated, and the heat of condensation is provided to the indoor heating. On the other hand, during cooling, the refrigerant discharged from the compressor passes through the outdoor heat exchanger (condensation), expansion valve, and indoor heat exchanger (evaporation) in this order through the main circuit, and returns to the compressor. The evaporation action of the refrigerant is performed, and the surrounding space is cooled by taking heat from the surroundings as heat of evaporation by this evaporation action, and cooling heat generated by this cooling is provided to the room cooling.

At the time of cooling, however, it is necessary to sufficiently cool the refrigerant introduced into the indoor heat exchanger in order to sufficiently evaporate the refrigerant in the indoor heat exchanger to promote the cooling action by the vaporization heat. To this end, a subcooling heat exchanger is often installed on the downstream side of the outdoor heat exchanger of the main circuit, and the subcooling heat exchanger is often employed to sufficiently cool the refrigerant.

Patent Document 1 describes a configuration in which a receiver is provided in a high-pressure refrigerant circuit in a main circuit in an air conditioner employing this subcooled heat exchanger. According to this document, the liquid receiver once separates the refrigerant in the high-pressure refrigerant circuit into a liquid refrigerant rich in a high boiling point refrigerant and a liquid refrigerant rich in a low boiling point refrigerant. The refrigerant rich in high boiling point and high boiling point refrigerant is heat-exchanged in the subcooling heat exchanger to thereby supercool the refrigerant rich in low boiling point refrigerant. In this way, when a mixed refrigerant is employed as the refrigerant, a refrigerant rich in low boiling point refrigerant flows into the main circuit, thereby reducing the pressure loss in the main circuit.

Patent Literature 2 discloses a configuration in which a liquid is separated from a refrigerant in an accumulator without providing a receiver in a high voltage circuit, and the accumulator is provided with a function of adjusting the amount of refrigerant flowing into the main circuit. This configuration eliminates the need for providing a receiver in the main circuit, and can provide a circuit configuration that does not require increasing the amount of refrigerant encapsulation as the receiver is provided.

According to the invention described in Patent Document 2, since the receiver is not provided in the main circuit, there is an advantage that the amount of refrigerant encapsulated into the main circuit can be saved. However, the structure of Patent Literature 2, in the heat exchange in the subcooled heat exchanger, bypasses the refrigerant from the downstream side of the subcooled heat exchanger of the main circuit, expands the bypassed refrigerant in the subcooled expansion valve, and then introduces the subcooled heat exchanger into the subcooled heat exchanger. The solar cell which adopts heat exchange with the refrigerant | coolant in a main circuit is adopted.

The reason for taking the heat source in the subcooling from the downstream side of the subcooling heat exchanger is that the system is completely liquefied in the case of the refrigerant via the subcooling heat exchanger, and therefore, hunting of the system caused by the gas-liquid two-phase refrigerant flowing into the subcooling expansion valve; This is because it prevents hunting, and it is considered that the supercooling effect of the refrigerant in the main circuit is sufficiently exerted by thermally contacting the refrigerant having a sufficiently low enthalpy completely liquefied with the refrigerant in the main circuit.

However, as in Patent Literature 2, if the bypass flow passage is branched from the downstream side of the supercooled heat exchanger, the refrigerant in the heat exchanged main circuit is immediately used as the supercooled refrigerant. The opening degree setting of the subcooled expansion valve is considered to be controlled to open and close based on the subcooling degree of the refrigerant downstream of the subcooled heat exchanger in the main circuit. Since the influence of the heat exchange in the heat exchanger immediately acts on the downstream refrigerant of the supercooled heat exchanger, and the state of the bypassed refrigerant is changed by this, there is a need to adjust the amount of refrigerant flowing to the supercooled heat exchanger again. . For this reason, the time until the amount of the refrigerant of the bypass refrigerant flowing to the subcooled heat exchanger becomes constant becomes long, and a problem arises in that the state of the refrigerant in the subcooled heat exchanger cannot be quickly determined.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and the technical problem is to devise a flow path of a refrigerant flowing into a subcooled heat exchanger, to quickly determine the amount of refrigerant supplied to the subcooled heat exchanger, and to stabilize the system quickly.

In order to solve the above technical problem, the invention of claim 1 is

Engine,

A compressor having a suction port for sucking the refrigerant and a discharge port for discharging the refrigerant, the compressor being driven by the engine to compress the refrigerant sucked from the suction port and discharge the refrigerant from the discharge port;

A main circuit whose one end communicates with the discharge port of this compressor and the other end communicates with the suction port of the compressor,

A condenser which is opened downstream of the discharge port of the compressor in the middle of the main circuit and condenses the supplied refrigerant;

An evaporator installed downstream of the condenser in the middle of the main circuit, for evaporating the supplied refrigerant;

An engine-driven air conditioner having a subcooling heat exchanger which is downstream of the condenser and at the same time located in the main circuit located upstream of the evaporator and supercools the refrigerant passing therethrough,

Branched from the main circuit at a portion located upstream of the subcooled heat exchanger in the main circuit, and via the subcooled heat exchange, at a portion located downstream of the indoor heat exchanger in the main circuit to the main circuit. A bypass passage to be joined, a subcooled expansion valve in the middle of the bypass passage and provided at a portion between the main circuit and a portion between the subcooled heat exchanger and control means for opening and closing the subcooled expansion valve. and,

The supercooled heat exchanger cools the refrigerant flowing in the main passage by the refrigerant flowing in the bypass passage,

The control means is an engine-driven air conditioner that controls the opening and closing of the subcooled expansion valve based on the subcooling degree of the refrigerant condensed in the condenser.

According to the invention of claim 1, the bypass passage branches off from the upstream side of the supercooling heat exchanger as a circumference. The subcooled expansion valve in the bypass passage is controlled to open and close based on the degree of subcooling of the refrigerant condensed in the condenser (outdoor heat exchanger during cooling). Therefore, when the subcooling degree of the refrigerant after condensation is small, that is, when the refrigerant after condensation is not sufficiently liquefied, the subcooling expansion valve can be closed to prevent the supercooling. On the other hand, when the subcooling degree of the refrigerant after condensation is large, that is, when the refrigerant after condensation is completely liquefied, the subcooling expansion valve is opened and heat exchange is performed in the subcooling heat exchanger. By doing in this way, the following three effects can be acquired.

(1) Hunting of the system caused by the introduction of the gas-liquid two-phase refrigerant into the subcooled expansion valve can be prevented.

(2) The refrigerant on the bypass side is sufficiently liquefied, that is, the heat exchange in the supercooled heat exchanger can be performed with the refrigerant having a high mass flow rate, and the refrigerant in the main circuit can be reliably subcooled.

(3) Since the refrigerant in the bypass flow path bypassed from the upstream side of the subcooled heat exchanger is used as the refrigerant for heat exchange in the subcooled heat exchanger, the state of the refrigerant flowing into the bypass side is determined by the opening and closing state of the subcooled expansion valve. Hard to be affected For this reason, the refrigerant | coolant circulation state in a subcooling heat exchanger is quickly determined.

In addition, in the invention of claim 1, "opening and controlling the supercooled expansion valve based on the supercooling degree of the refrigerant condensed in the condenser" means that the supercooled of the refrigerant condensed in the condenser is controlled when the supercooled expansion valve is opened and closed. This means that the figure is considered as a factor of the opening and closing control. Therefore, after the subcooling degree is considered, the subcooling expansion valve may be opened and closed as a result based on other factors. In a preferred embodiment for carrying out the invention described later, the upper limit calculation subcooling corresponds to the subcooling degree in the present invention, but as a result, other factors, for example, the subcooling of the refrigerant supercooled in the subcooling heat exchanger (invention to be described later) Even if the subcooled expansion valve is opened or closed based on the required calculated subcooling degree) in the preferred embodiment for carrying out the present invention, the upper limit calculated subcooling degree does not matter. In the invention according to claim 1, "opening and closing the supercooled expansion valve" shall also include opening and controlling the supercooled expansion valve.

EMBODIMENT OF THE INVENTION Hereinafter, the preferable form for implementing this invention is demonstrated based on drawing.

1 is a schematic configuration diagram of an engine-driven air conditioner in this example. In FIG. 1, the engine-driven air conditioner 100 in this example can be roughly divided into the outdoor unit 200 and the indoor unit 300. As shown in FIG.

The outdoor unit 200 includes an engine 201, a compressor 202, a four-way switching valve 203, an outdoor heat exchanger 204, an accumulator 206, a main circuit 207 communicating these, and a refrigerant-cooled water heat exchanger. 205, the low-temperature heating bypass passage 208 in which the refrigerant-cooling water heat exchanger 205 is installed, the subcooling heat exchanger 213, and the subcooling bypass passage 214 are the main components. It is in the state accommodated in the housing (not shown) of the.

The engine 201 may be any type as long as it functions as a prime mover. In the engine driven air conditioner, a gas engine driven by gas fuel is generally used.

The compressor 202 is connected to the output shaft of the engine 201 via a clutch mechanism (not shown), and the drive force of the engine 201 is transmitted and operates. In addition, the compressor 20 has a suction port 202a and a discharge port 202b, which are communication ports for the outside, and suction the refrigerant from the suction port 202a, increase the pressure of the refrigerant sucked from the inside, and It discharges from the discharge port 202b. In addition, any type of compressor may be used, but a Recipro type compressor or a Scroll type compressor is mainly used. In addition, the number of compressors may be one or a plurality depending on the air conditioning capability or the control specification.

The discharge port 202b of the compressor 202 communicates with the four-way switching valve 203 through the outdoor first passage 207a in the main circuit 207. The four-way switching valve 203 includes a compressor input port 203a, a first output port 203b, a second output port 203c, and an accumulator output port 203d, and includes a compressor input port 203a and a first input port 203a. The first output port 203b communicates with the first state where the second output port 203c and the accumulator output port 203d communicate with each other, and the compressor input port 203a and the second output port 203c communicate with each other. On the other hand, the valve can be switched to the second state in which the first output port 203b and the accumulator output port 203d communicate with each other. When the four-way switching valve 203 is in the first state, room heating is performed, and in the second state, room cooling is performed.

The outdoor second passage 207b of the main circuit 207 communicates with the first output port 203b of the four-way switching valve 203. The open / close valve mechanism 41b is connected to the end of this outdoor side second passage 207b.

The outdoor third passage 207c of the main circuit 207 communicates with the second output port 203c of the four-way switching valve 203. The outdoor side third passage 207c is provided with an outdoor heat exchanger 204, a main solenoid expansion valve 209, a subcooling heat exchanger 213, and an open / close valve mechanism 41c connected to the end thereof. It is.

The outdoor heat exchanger 204 heat-exchanges the refrigerant introduced into the outside air, and specifically, connects to a meandering flow path through which the refrigerant flows, and a meandering flow path. Take a shape of stacking plate-shaped plates with one pin installed. The meandering flow path through which the coolant flows is introduced into the adjacent plate at the side end of each plate, whereby the coolant flows through the meandering flow path in each plate through one passage. The heat collected from the surrounding air is transferred from the fins to the refrigerant in the meandering flow path while the meandering flow path in each plate flows, and heat exchange is performed. In this example, the plate is laminated in four layers, and at the same time, the innermost plate of the plate serves as a separate passage from the refrigerant passage flowing in the remaining three layers, and functions as a radiator. have.

As can be seen from the figure, a fan 215 is disposed adjacent to the outdoor heat exchanger 204. In this example, three fans 215 are arranged. The fan 215 is driven to rotate to blow outside air into the outdoor heat exchanger 204, and to perform heat exchange with the refrigerant flowing through the outdoor heat exchanger 204 and the blown outside air. In addition, in this example, operation is performed by making the rotation speed of each fan 215 different. When all the fans are operated at the same rotational speed, a fluttering sound or the like accompanying the rotation of the fan may resonate. In this case, a very loud beeping sound may occur. In other cases, the fluttering sound is not resonant and the occurrence of the bent sound can be prevented. In addition, each fan 215 is rotationally controlled individually, and even if one fan fails, the other fan is made to rotate. By such control, it is possible to avoid stopping all the fans when the fan rotation control means is broken. In addition, a DC motor is employed in this example as a drive motor for driving each fan.

The main solenoid expansion valve 209 is a valve whose valve opening degree is adjustable by electrical control, and it is possible to control the flow rate of the refrigerant passing through the outdoor side third passage 207c by adjusting the valve opening degree. Will be done.

As can be seen from the figure, one end of the cooling passage 207f is formed at a portion of the point C which is a portion between the outdoor heat exchanger 204 and the main solenoid expansion valve 209 of the outdoor third passage 207c. Connected. The other end of the cooling passage 207f is connected to a point D which is a position beyond the main solenoid expansion valve 209 in the outdoor third passage 207c from the point C, and connects the cooling passage 207f. By passing through the refrigerant, the main electromagnetic expansion valve 209 is configured to bypass. In the middle of the cooling passage 207f, a one-way valve 211 is provided that allows a refrigerant flow from the point C to the point D and blocks the refrigerant flow from the point D to the point C direction. For this reason, only the refrigerant flowing from the outdoor heat exchanger 204 side flows to the cooling passage 207f.

The outdoor side fourth passage 207d of the main circuit 207 is connected to the accumulator output port 203d of the four-way switching valve 203. An end portion of the fourth outdoor passage 207d penetrates into the accumulator 206. From the accumulator 206, the outdoor side 5th passage 207e of the main circuit 207 is connected, and this outdoor side 5th passage 207e is connected to the suction port 202a of the compressor 202.

Moreover, as can be seen from the figure, one end of the low-temperature heating bypass passage 208 branched from this outdoor side third passage 207c is connected to the point A in the outdoor side third passage 207c. A refrigerant-cooling water heat exchanger 205 and a sub solenoid expansion valve 210 are provided in the middle of the low temperature heating bypass passage 208. The other end of the low-temperature heating bypass passage 208 is configured to join the outdoor side fourth passage 207d at point B in the figure.

The refrigerant-cooling water heat exchanger 205 heat-exchanges the cooling water for cooling the engine 201 and the refrigerant flowing through the bypass passage 208 for low temperature heating. In this example, a plurality of plate-like flat plates are folded and folded. Heat exchange is adopted. The cooling water introduced into the refrigerant-cooling water heat exchanger 205 is heated because the cooling water after cooling the engine 201 is heated. Thus, in the refrigerant-cooling water heat exchanger 205, the refrigerant is heated by the heated cooling water.

Like the main solenoid expansion valve 209, the sub solenoid expansion valve 210 is a valve whose valve opening degree is adjustable by electrical control, and the refrigerant passing through the low-temperature heating bypass passage 208 by adjusting the valve opening degree. It is possible to control the flow rate.

The main solenoid expansion valve 209 and the sub solenoid expansion valve 210 are electrically connected to the control means 212. This control means 212 is provided with the function which sets the valve opening degree of both expansion valves 209 and 210 from the state of the refrigerant | coolant which flows in each refrigerant | coolant channel | path, the state of each apparatus, etc.

Moreover, the subcooling heat exchanger 213 is provided in the outdoor side 3rd channel 207c. The subcooling heat exchanger 213 further cools the refrigerant in the outdoor third passage 207c, and improves the cooling efficiency at the time of cooling by increasing the degree of subcooling of the refrigerant. The supercooled heat exchanger 213 is arranged so that the refrigerant condensed in the outdoor heat exchanger 204 is introduced during the cooling fare. That is, the subcooling heat exchanger 213 is provided downstream of the outdoor heat exchanger 213 at the time of cooling.

Moreover, from the part between the subcooling heat exchanger 213 and point A of the outdoor side 3rd passage 207c, ie, the point E part which is the upstream side at the time of cooling of the subcooling heat exchanger 213, the outdoor side 3rd passage 207c The bypass passage 214 for subcooling branched from the () is connected. The subcooling bypass passage 214 is configured such that the subcooling expansion valve 216 is provided in the middle thereof, and joins the outdoor side fourth passage 207d at the point F portion via the subcooling heat exchanger 213. Becomes The subcooled expansion valve 216 provided in the subcooling bypass passage 214 is electrically connected to the subcooled expansion valve control means 220, and the subcooled expansion valve (216) is instructed by the supercooled expansion valve control means 220. 216 is controlled to open and close.

Moreover, as shown in the figure, the temperature sensor 217 is provided in the part of the outdoor side 3rd passage 207c between the outdoor heat exchanger 204 and the point C. As shown in FIG. Since the temperature sensor 217 is located downstream of the outdoor heat exchanger 204 at the time of cooling, the exit temperature of the outdoor heat exchanger 204 at the time of cooling is detected. Moreover, the pressure sensor 219 is provided in the outdoor 1st channel 207a. Since the outdoor first passage 207a communicates with the discharge port 202b of the compressor 202, the pressure sensor 219 detects the discharge pressure from the compressor 202. In addition, at the time of cooling, since the outdoor first passage 207a communicates with the outdoor heat exchanger 204 via the four-way switching valve 203 and the outdoor third passage 207c, the pressure sensor 219 is outdoors. It is also possible to detect the condensation pressure of the refrigerant when introduced into the heat exchanger 204 and condensed. In addition, the subcooling temperature sensor 218 is provided in the part of the outdoor side 3rd passage 207c between the subcooling heat exchanger 213 and the on-off valve mechanism 41c. Since the subcooling temperature sensor 218 is located downstream of the subcooling heat exchanger 213 at the time of cooling, the outlet temperature of the subcooling heat exchanger 213 at the time of cooling is detected by the subcooling temperature sensor 218. do.

The information detected by the temperature sensor 217, the subcooled temperature sensor 218, and the pressure sensor 219 is input to the subcooled expansion valve control means 220. The subcooled expansion valve control unit 220 calculates the subcooling degree of the refrigerant from the input temperature information and the pressure information, and controls the opening and closing of the subcooling expansion valve 216 based on the calculated subcooling degree of the refrigerant. In addition, in this specification, a "supercooling degree" means that the refrigerant temperature at a certain state point is from the saturated liquid temperature (the boundary temperature of the liquid phase and gas-liquid mixed phase in the Moriel diagram) at the pressure at that state point. It is the quantity which shows how much the liquid phase is separated, and a unit is represented by temperature. Therefore, when a supercooling degree is large at a certain pressure, it shows that it is a refrigerant | coolant which is lower in temperature and low in enthalpy.

The indoor unit 300 has the indoor heat exchanger 301, the expansion valve 302, and the main circuit 301 which connects these as a main component.

The configuration of the main circuit 301 of the indoor unit 300 includes the indoor first passage 301c connected to the on-off valve mechanism 41c and the indoor second passage 301b connected to the open / close valve mechanism 41b. And the interior third passage 301d communicating the interior first passage 301c and the interior second passage 301b. The indoor side third passage 301d is required for the number of installation of the indoor heat exchanger. For example, if there are two indoor heat exchangers, two indoor side 3rd passages 301d will be needed.

An indoor heat exchanger 302 and an expansion / valve 303 are provided in the indoor side third passage 301d. The indoor heat exchanger 302 heat-exchanges indoor air with the refrigerant | coolant introduced inside, and the concrete structure is a structure similar to an outdoor heat exchanger. The expansion valve 303 throttles the flow path to expand the refrigerant flowing therein and to reduce the pressure.

As can be seen from the above description, the main circuit 207 on the outdoor unit 200 side and the main circuit 301 on the indoor unit 300 side communicate with each other in the open / close valve mechanisms 41b and 41c. . Thereby, the compressor 202, the outdoor heat exchanger 204, the indoor heat exchanger 301, and the expansion valve 302 are connected by the main circuits 207 and 301, respectively.

In the above configuration, the operation of the engine driven air conditioner 100 in this example will be described. First, the operation at the time of heating is demonstrated.

(When heating)

When the compressor 202 is driven by driving the engine 201, the compressor 202 sucks gaseous refrigerant from the intake port 202a side, compresses the gaseous refrigerant therein, and discharges the gaseous refrigerant of a predetermined high pressure into the discharge port ( Discharge from 202b). The refrigerant discharged from the compressor 202 enters the compressor input port 203a of the four-way switching valve 203 through the outdoor first passage 207a. At the time of heating, since the four-way switching valve 203 is in the first state, the refrigerant entering the compressor input port 203a exits the four-way switching valve 203 from the first output port 203b. The outdoor second passage 207b flows. And it flows into the indoor unit 300 from the indoor side 1st passage 301b via the open / close valve mechanism 41b at the edge part of the outdoor side 2nd passage 207b.

Since the indoor third passage 301d is connected to the indoor first passage 301b in the indoor unit 300, the coolant flows to the indoor third passage 301d. The refrigerant flowing into the indoor third passage 301d again enters the indoor heat exchanger 302. The refrigerant introduced into the indoor heat exchanger 302 is a high-pressure gas state refrigerant compressed by the compressor 202, and the gas state refrigerant exchanges heat with ambient air in the indoor heat exchanger 302 to condense (liquefy). do. As the refrigerant condenses, the refrigerant discharges condensation heat in rotation, so that the surrounding air is heated. In this way, at the time of heating, indoor air is heated by the condensation action of the refrigerant operated by the indoor heat exchanger 302, so that indoor heating is realized.

The refrigerant condensed in the indoor heat exchanger 302 exits the indoor heat exchanger 302 in a liquid state or a gas-liquid two-phase state. Next, in the expansion valve 303 provided downstream of the indoor heat exchanger 302 (downstream when heating), the refrigerant is expanded, and the pressure decreases to become a low pressure refrigerant. The low pressure refrigerant flows from the indoor third passage 301d to the indoor second passage 301c and passes from the outdoor third passage 207c to the outdoor unit 200 via the open / close valve mechanism 41c. Flows into.

The refrigerant entering the outdoor third passage 207c of the outdoor unit 200 is first introduced into the subcooling heat exchanger 213. However, at the time of heating, the subcooled expansion valve 216 is closed. Therefore, the subcooled heat exchanger 213 does not perform heat exchange, and the refrigerant passes only through the heat exchanger 213. Thereafter, the coolant is classified into a coolant flowing through the outdoor third third passage 207c and a coolant flowing through the low temperature heating bypass passage 208 at the point A. The refrigerant flowing from the point A toward the outdoor third passage 207c enters the main solenoid expansion valve 209 provided on the downstream side (downstream side at the time of heating) again. As described above, the main solenoid expansion valve 209 operates on the basis of an electrical input signal and is a valve capable of adjusting the opening degree. Therefore, the amount of refrigerant flowing into the outdoor heat exchanger 204 from the outdoor third passage 207c is adjusted by adjusting the opening degree of the main solenoid expansion valve 209.

The gas-liquid two-phase refrigerant flowing into the outdoor heat exchanger 204 via the main solenoid expansion valve 209 performs heat exchange with the outdoor air in the outdoor heat exchanger 204, and receives the heat of the external air to evaporate. By this evaporation, the refrigerant evaporates and becomes a gaseous refrigerant. Then exit the outdoor heat exchanger 204.

On the other hand, the refrigerant flowing from the point A toward the low temperature heating bypass passage 208 side enters the sub solenoid expansion valve 210. Like the main solenoid expansion valve 209, this sub solenoid expansion valve 210 also operates based on an electrical input signal, and is a valve which can adjust an opening degree. Therefore, the flow rate of the refrigerant flowing through the low-temperature heating bypass passage 208 is adjusted by adjusting the opening degree of the sub solenoid expansion valve 210.

The refrigerant flow-modulated by the sub solenoid expansion valve 210 also flows into the refrigerant-cooling water heat exchanger 205 provided downstream thereof (downstream side during heating). In this refrigerant-cooling water heat exchanger (205), the refrigerant receives heat from the cooling water cooling the engine and evaporates. By this evaporation action, the refrigerant vaporizes into a gas refrigerant. And a refrigerant-cooled water heat exchanger 205.

The refrigerant leaving the outdoor heat exchanger 204 enters the four-way switching valve 203 at the second output port 203c. As described above, since the four-way switching valve is in the first state during heating, the refrigerant entering the second output port 203c exits the four-way switching valve 203 through the accumulator output port 203d. The front outdoor side fourth passage 207d flows. On the other hand, the refrigerant leaving the refrigerant-cooling water heat exchanger 205 again flows through the low-temperature heating bypass passage 208 to the downstream side (downstream side during heating). The downstream end (downstream side at the time of heating) of the bypass passage 208 for low temperature heating joins to the outdoor side 4th passage 207d at point B. FIG. Thus, at this point B, the refrigerant exiting the outdoor heat exchanger 204 and the refrigerant exiting the refrigerant-cooling water heat exchanger 205 join. And the refrigerant | coolant which merged flows back to the downstream side (downstream side at the time of heating) again and enters the accumulator 206 again. In the accumulator 206, the refrigerant is separated into a gas phase part and a liquid phase part. In the accumulator 206, only the refrigerant (gas refrigerant) in the gas phase part is sucked into the compressor 202 from the suction port 202a of the compressor 202.

In heating, the above cycle is repeated to generate heat in the indoor heat exchanger 302 to perform indoor heating.

Next, operation | movement at the time of cooling is demonstrated.

(When cooling)

When the compressor 202 is driven by the driving of the engine 201, the compressor 202 sucks gaseous refrigerant from the intake port 202a side, compresses the gaseous refrigerant therein, and discharges the gaseous refrigerant of a predetermined high pressure to the discharge port ( Discharge from 202b). The refrigerant discharged from the compressor 202 enters the compressor input port 203a of the four-way switching valve 203 through the outdoor refrigerant passage 207a. At the time of cooling, since the four-way switching valve 203 is in the second state, the refrigerant entering the compressor input port 203a exits the four-way switching valve 203 through the second output port 203c, and in front of it. The outdoor side of the third passage 207c flows. Then, the outdoor heat exchanger 204 installed in the outdoor third passage 207c enters. The refrigerant introduced into the outdoor heat exchanger 204 is a high-pressure gas state refrigerant compressed by the compressor 202, and the gas state refrigerant exchanges heat with outside air in the outdoor heat exchanger 204 to condense (liquefy). .

The refrigerant condensed in the outdoor heat exchanger 204 becomes a liquid state or a gas-liquid two-phase state and exits the outdoor heat exchanger 204. Here, although the main solenoid expansion valve 209 is provided in the downstream (downstream side of cooling) position of the outdoor heat exchanger 204 in the outdoor side 3rd passage 207c, at the time of cooling, this main solenoid expansion valve is carried out. 209 is in a completely closed state. Therefore, the refrigerant flows through the cooling passage 207f from the point C. The one-way valve 211 is provided in the middle of the cooling passage 207f. However, since the one-way valve 211 allows a flow from the point C to the point D, the refrigerant flowing from the point C is one-way. Pass the valve and head to point D.

The coolant through the cooling passage 207f from the point C joins the outdoor third third passage 207c at the point D again. Then, the outdoor third passage 207c flows again and branches from the point E portion to the outdoor third passage 207c and the subcooling bypass passage 214. The refrigerant flowing from the point E portion into the outdoor third passage 207c is introduced into the subcooling heat exchanger 213 as it is. On the other hand, the refrigerant flowing from the point E portion to the subcooling bypass passage 214 is expanded by the subcooling expansion valve 216 provided in the subcooling bypass passage 214, and is reduced in pressure. In the subcooling heat exchanger 213, the refrigerant flowing through the third outdoor passage 207c and the refrigerant flowing through the subcooling bypass passage 214 perform heat exchange. In this case, since the refrigerant flowing through the subcooling bypass passage 214 is expanded by the subcooling expansion valve 216 and has a lower temperature and lower pressure than the refrigerant flowing through the outdoor third passage, the outdoor third passage ( The refrigerant of 207c is filled by the refrigerant of the subcooling bypass passage 214, and is cooled more. In this way, the refrigerant in the outdoor-side third passage 207c is subcooled, and then the subcooled heat exchanger 213 exits. The refrigerant leaving the supercooled heat exchanger 213 flows into the indoor unit 300 from the indoor second passage 301c via the on-off valve mechanism 41c.

The refrigerant flowing into the indoor unit 300 flows from the indoor second passage 301c again to the indoor third passage 301d and to the expansion valve 303 provided in the indoor third passage 301d. To this. In this expansion valve 303, the refrigerant expands to low pressure. The refrigerant depressurized by the expansion valve 303 again reaches the indoor heat exchanger 302 installed on the downstream side (downstream during cooling).

The gas-liquid two-phase refrigerant introduced into the indoor heat exchanger 302 heat exchanges with the indoor air in the indoor heat exchanger 302, and receives the heat from the outside air and evaporates it. The refrigerant vaporizes by this evaporation action. At this time, the refrigerant takes heat from the surroundings and cools the surrounding air. In this way, the indoor air is cooled, and a cooling effect is achieved.

The refrigerant evaporated in the indoor heat exchanger 302 again flows through the indoor side first passage 301b on the downstream side (downstream during cooling) and passes through the open / close valve mechanism 41b to the outdoor side second passage 207b. Enters the outdoor unit (200). The refrigerant flows again through the outdoor second passage 207b and enters the four-way switching valve 203 from the first output port 203b. As described above, since the four-way switching valve is in the second state at the time of cooling, the refrigerant entering the first output port 203b exits the four-way switching valve 203 from the accumulator output port 203d. In front of it, the outdoor side fourth passage 207d flows. Since the subcooling bypass passage 214 joins to the fourth outdoor passage 207d at the point F, the refrigerant flowing through the subcooling bypass passage 214 and the outdoor fourth passage 207d are connected. Flowing refrigerant joins at point F and then enters accumulator 206. In the accumulator 206, the refrigerant is separated into a gas phase part and a liquid phase part. In the accumulator 206, only the refrigerant (gas refrigerant) in the gas phase part is sucked into the compressor 202 from the suction port 202a of the compressor 202.

At the time of cooling, by repeating the said cycle, it receives heat by indoor heat exchange and performs room cooling.

At the time of cooling, as described above, the subcooled heat exchanger 213 subcools the refrigerant in the main circuit. In that case, the amount of refrigerant flowing to the subcooling bypass passage 214 is subcooled expansion valve 216. I regulate it by the opening degree of). The opening degree of the subcooled expansion valve 216 is controlled by the subcooled expansion valve control means 220. In this example, the supercooled expansion valve control means 220 includes temperature information and condensation pressure information from the temperature sensor 217 and the pressure sensor 219 provided downstream of the outdoor heat exchanger 204 (downstream when cooling). The subcooling temperature information from the subcooling temperature sensor 218 provided on the outlet side (downstream side of cooling) of the subcooling heat exchanger 213 is inputted, respectively. The subcooled expansion valve control means 220 sets the following two subcooled expansion valve opening degrees based on this information.

(1) Setting of required opening degree

First, the subcooling degree of the refrigerant at the outlet of the subcooling heat exchanger 213 is calculated from the subcooling temperature information from the subcooling temperature sensor 218 and the condensation pressure information from the pressure sensor 219 (required calculation subcooling degree). In addition, the subcooling degree target value at the outlet of the subcooling heat exchanger 213 is set in advance (required target subcooling degree). In addition, the required target supercooling degree can be set such that the degree of supercooling is sufficient to procure that the pressure loss is increased due to the length of the pipe constituting the main circuit and the cooling capacity is lowered. For example, the required target subcooling degree can be set to 25 degrees. Then, the required calculated subcooling degree is compared with the required target subcooling degree, and the required opening degree of the subcooled expansion valve 216 is set from the comparison result. Specifically, when the required calculation subcooling degree is greater than the required target subcooling degree, the required opening degree is set small, while when the required calculation subcooling temperature is smaller than the required target subcooling degree, the required opening degree is set large. In setting the required opening degree, in order to prevent the subcooled expansion valve from being hunted, an opening degree setting in which a temperature dead zone is provided for the required target supercooling degree may be used.

(2) Setting of the upper limit opening degree

First, the supercooling degree of the refrigerant at the outlet of the outdoor heat exchanger 204 is calculated from the temperature information from the temperature sensor 217 and the condensation pressure from the pressure sensor 219 (upper limit calculation subcooling). In addition, the target value of the subcooling degree of the refrigerant at the outlet of the outdoor heat exchanger 204 is set in advance (upper limit subcooling degree). In addition, this upper limit target subcooling degree can set the subcooling degree at which the refrigerant | coolant which exited the outdoor heat exchanger 204 is fully liquefied. In this case, if the subcooling degree is an integer, the liquid will be completely liquefied. However, the upper limit target subcooling degree can be set to 4 degrees, for example to some extent. The upper limit calculation subcooling degree is compared with the upper limit target subcooling degree, and the upper limit opening degree of the subcooling expansion valve 216 is set from the comparison result. Specifically, when the upper limit calculation subcooling degree is greater than the upper limit target subcooling degree, the upper limit opening degree is set large, while when the upper limit calculation subcooling degree is smaller than the upper limit target subcooling degree, the upper limit opening degree is set small. In the setting of the upper limit opening degree, in order to prevent the subcooled expansion valve from hunting, the opening degree setting in which the temperature dead zone is provided for the upper limit target subcooling degree may be used.

When the required opening degree and the upper limit opening degree are set as described above, the required opening degree and the upper limit opening degree are compared next, and the smaller one is set as the opening degree of the subcooled expansion valve. The subcooled expansion valve control means 220 sends a control command to the subcooled expansion valve 216 such that the subcooled expansion valve 216 is opened at this degree, and the subcooled expansion valve 216 is the opening degree determined by the command.

By controlling the subcooled expansion valve 216 in this way, the liquefaction of the refrigerant at the outlet of the outdoor heat exchanger 204 is incomplete or the system becomes unstable and the controllability of the subcooled expansion valve 216 is prevented. It is possible to prevent the cooling capacity from being lowered due to factors such as the length of the pipe without harming it. As can be seen from FIG. 1, the subcooling bypass passage is bypassed from the upstream side of the subcooling heat exchanger 213 not from the downstream side of the subcooling heat exchanger 213. The refrigerant state on the bypass side does not change, the refrigerant state can be quickly determined, and contributed by the stability of the system.

Claims (1)

Engine, A compressor having a suction port for sucking the refrigerant and a discharge port for discharging the refrigerant, the compressor being driven by the engine to compress the refrigerant sucked from the suction port and discharged from the discharge port; A main circuit whose one end communicates with the discharge port of this compressor and the other end communicates with the suction port of the compressor; A condenser provided downstream of the discharge port of the compressor in the middle of the main circuit and condensing the supplied refrigerant; An evaporator installed downstream of the condenser in the middle of the main circuit, for evaporating the supplied refrigerant; An engine-driven air conditioner having a subcooling heat exchanger disposed in the main circuit downstream of the condenser and at the same time located upstream of the evaporator and for supercooling the refrigerant passing therethrough, The main circuit branches from the main circuit at a portion located upstream of the subcooled heat exchanger in the main circuit, and is located at a downstream side of the indoor heat exchanger in the main circuit via the subcooled heat exchanger. A bypass passage joining the circuit, a subcooled expansion valve disposed in the middle of the bypass passage and at the same time between the main circuit branch and the subcooling heat exchanger, and a supercooling valve for opening and closing the supercooled expansion valve. An expansion valve control means, The supercooled heat exchanger cools the refrigerant flowing in the main passage by the refrigerant flowing in the bypass passage, And the subcooled expansion valve control means controls the opening and closing of the subcooled expansion valve based on the subcooling degree of the refrigerant condensed in the condenser.

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