JP2014066439A - Engine driven type air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine driven type air conditioner which evaporates a refrigerant using an outdoor heat exchanger even when an outdoor temperature is low, and in which stagnation of a liquid refrigerant is controlled.SOLUTION: When it is predicted that the stagnation may occur, the flow of a refrigerant in a twelfth pipeline L12 from an eleventh pipeline L11 toward a tenth pipeline L10 is blocked, so that it is prevented that a refrigerant pressure in an engine exhaust heat reclaimer 18 exerts influence on a refrigerant pressure in an outdoor heat exchanger 16. Thereby, the refrigerant pressure in the outdoor heat exchanger 16 is decreased by adjustment of an electronic expansion valve 17a. As a result, even when the outdoor temperature is so low that the stagnation may occur, the outdoor heat exchanger 16 functions as an evaporator, and the refrigerant can be evaporated in the outdoor heat exchanger 16. In addition, the refrigerant is evaporated in the outdoor heat exchanger 16, so that the stagnation of the liquid refrigerant can be also prevented in the outdoor heat exchanger 16.

Description

  The present invention relates to an engine-driven air conditioner.

  The engine-driven air conditioner compresses refrigerant with a compressor driven by engine power, and air-conditions the room using the phase change of the compressed refrigerant. Therefore, this type of air conditioner includes a condenser that condenses the refrigerant and an evaporator that evaporates the refrigerant. During indoor heating, an indoor heat exchanger installed indoors functions as a condenser, and an outdoor heat exchanger installed outdoors functions as an evaporator. On the other hand, during indoor cooling, the indoor heat exchanger functions as an evaporator, and the outdoor heat exchanger functions as a condenser.

  An engine-driven air conditioner equipped with an engine exhaust heat recovery device is also known. A part of the refrigerant discharged from the outdoor heat exchanger is supplied to the engine exhaust heat recovery device. The refrigerant supplied to the engine exhaust heat recovery device exchanges heat with engine exhaust heat (for example, engine coolant after the engine is cooled). The refrigerant is overheated by the engine exhaust heat recovery device.

  As described above, the outdoor heat exchanger functions as an evaporator during heating. However, when the outside air temperature is extremely low (for example, when the outside air temperature is lower than the evaporation temperature of the refrigerant), the outdoor heat exchanger cools the heat of the outside air as a refrigerant. It becomes difficult to make it take in. In such a case, the flow rate of the refrigerant supplied to the outdoor heat exchanger is adjusted by adjusting the opening degree of the electronic expansion valve attached to the upstream side of the outdoor heat exchanger. As a result, the refrigerant pressure is lowered, and the refrigerant can be evaporated by the outdoor heat exchanger even when the outside air temperature is low.

  However, when an engine exhaust heat recovery unit is provided to overheat the refrigerant, the refrigerant pressure in the engine exhaust heat recovery unit affects the refrigerant pressure in the outdoor heat exchanger. Even if the refrigerant flow in the outdoor heat exchanger is reduced by adjusting the refrigerant flow rate with an electronic expansion valve so that the refrigerant in the outdoor heat exchanger easily evaporates at low The refrigerant pressure in the outdoor heat exchanger cannot be lowered to a desired pressure by being pulled by the pressure. That is, the low pressure required for the evaporation of the refrigerant cannot be obtained. For this reason, the refrigerant cannot be evaporated well in the outdoor heat exchanger. In addition, the evaporation capacity in the engine exhaust heat recovery unit exceeds the evaporation capacity in the outdoor heat exchanger, and as a result, the refrigerant may condense in the outdoor heat exchanger. In such a situation, the liquid refrigerant is trapped in the outdoor heat exchanger and the liquid refrigerant accumulates in the outdoor heat exchanger, that is, stagnation occurs. The occurrence of stagnation causes a decrease in the amount of refrigerant circulating in the refrigerant circuit, which in turn leads to a stop of the air conditioning operation.

  Patent Documents 1 and 2 disclose an engine-driven air conditioner that can effectively prevent the occurrence of sleeping. According to the engine-driven air conditioner disclosed in Patent Documents 1 and 2, on-off valves are provided on the upstream side and the downstream side of the outdoor heat exchanger. When the outside air temperature is lower than the set temperature, that is, when it is predicted that stagnation will occur, the on-off valves provided on the upstream side and the downstream side of the outdoor heat exchanger are both closed, and the indoor heat The refrigerant exiting the exchanger is configured to pass through the engine exhaust heat recovery unit without passing through the outdoor heat exchanger. According to this, since the entrance and exit of the outdoor heat exchanger are blocked when the outside air temperature, which is thought to cause refrigerant stagnation in the outdoor heat exchanger, is low, the stagnation of the refrigerant in the outdoor heat exchanger is prevented. Generation is effectively suppressed.

JP 2005-16805 A JP 2005-283025 A

(Problems to be solved by the invention)
However, according to the engine-driven air conditioners described in Patent Documents 1 and 2, since the use of the outdoor heat exchanger is prohibited in order to prevent stagnation, the evaporation capability of the outdoor heat exchanger is completely utilized. Can not do it. For this reason, the air conditioning capacity is reduced. Further, when the inlet and outlet of the outdoor heat exchanger are blocked while liquid refrigerant is accumulated in the outdoor heat exchanger, a phenomenon similar to that of stagnation occurs, and the operation cannot be continued due to insufficient refrigerant operation. In addition, when it is considered that stagnation occurs in the outdoor heat exchanger, first, after the operation of releasing the refrigerant from the outdoor heat exchanger into the refrigerant circuit (that is, the operation of discharging the refrigerant from the outdoor heat exchanger) is executed, The inlet and outlet of the outdoor heat exchanger are blocked. However, in this case, it takes time until the operation is started in a state where the inlet and outlet of the outdoor heat exchanger are blocked, which impedes the comfort of air conditioning.

  The present invention is an engine drive that can evaporate refrigerant using an outdoor heat exchanger even when the outside air temperature is low, and effectively suppresses stagnation of liquid refrigerant in the outdoor heat exchanger. It aims at providing a type air conditioner.

(Means for solving the problem)
The present invention includes a first compressor and a second compressor that are driven by an engine to suck in a refrigerant and compress and discharge the sucked refrigerant, and the first compressor and the second compressor that are provided indoors and are heated. An indoor heat exchanger that is supplied with the refrigerant compressed in the above, heat-exchanges the supplied refrigerant and indoor air to condense the refrigerant, and an expansion valve that expands the refrigerant discharged from the indoor heat exchanger during heating An outdoor heat exchanger that is provided outside and is supplied with refrigerant expanded by the expansion valve during heating, heats the supplied refrigerant and outside air to evaporate the refrigerant, and from the indoor heat exchanger during heating The discharged refrigerant is supplied, the engine exhaust heat recovery unit that exchanges heat between the supplied refrigerant and the exhaust heat of the engine, and the refrigerant discharged from the outdoor heat exchanger The outdoor heat exchanger side intake pipe connecting the outdoor heat exchanger and the first compressor so as to be sucked into the first compressor, and the refrigerant discharged from the engine exhaust heat recovery device sucks into the second compressor. The exhaust heat recovery device side suction pipe connecting the engine exhaust heat recovery device and the second compressor, and the connection connecting the outdoor heat exchanger side suction piping and the exhaust heat recovery device side suction piping When the refrigerant is expected to stagnate at least in the outdoor heat exchanger, the exhaust heat recovery side suction pipe is changed to the outdoor heat exchanger side suction pipe. There is provided an engine-driven air conditioner comprising: a valve member that blocks a flow of refrigerant in the connecting pipe heading.

  According to the present invention, when it is predicted that stagnation will occur, the flow of the refrigerant in the connection piping from the exhaust heat recovery device side suction piping to the outdoor heat exchanger side suction piping is blocked. The exhaust heat recovery device side suction pipe is connected to the engine exhaust heat recovery device, and the outdoor heat exchanger side suction piping is connected to the outdoor heat exchanger. The refrigerant in the engine exhaust heat recovery unit is prevented from moving toward the outdoor heat exchanger. This prevents the refrigerant pressure in the engine exhaust heat recovery unit from affecting the refrigerant pressure in the outdoor heat exchanger. Therefore, by adjusting the flow rate of the refrigerant supplied to the outdoor heat exchanger with the expansion valve, the refrigerant easily evaporates in the outdoor heat exchanger without worrying about the refrigerant pressure in the engine exhaust heat recovery unit. As described above, the refrigerant pressure in the outdoor heat exchanger can be reduced. As a result, even if the outside air temperature at which stagnation is predicted to occur is extremely low, the outdoor heat exchanger can function as an evaporator, and the refrigerant can be evaporated in the outdoor heat exchanger. Moreover, since the refrigerant is evaporated in the outdoor heat exchanger, it is possible to prevent the liquid refrigerant from sleeping in the outdoor heat exchanger.

  In the above invention, the engine exhaust heat recovery device may be any one as long as it can evaporate the refrigerant by using the exhaust heat of the engine. For example, the engine exhaust heat recovery device may be configured so that the heated cooling water after cooling the engine is brought into thermal contact with the refrigerant to evaporate the refrigerant, or the engine exhaust is brought into thermal contact with the refrigerant. The engine exhaust heat recovery unit may be configured to evaporate the refrigerant.

  Further, the valve member may be anything as long as the refrigerant flow from the exhaust heat recovery device side suction pipe to the outdoor heat exchanger side suction pipe is blocked. In particular, when the valve member is predicted to stagnate the refrigerant in the outdoor heat exchanger, the valve member is closed, and when the stagnation of the refrigerant in the outdoor heat exchanger is predicted not to occur. It is good that it is an on-off valve that opens. In this case, the engine-driven air conditioner determines whether or not refrigerant stagnation occurs in the outdoor heat exchanger, and determines that refrigerant stagnation occurs in the outdoor heat exchanger. It is good to further have a control part which controls the on-off valve so that the on-off valve opens when it is judged that the on-off valve is closed and the refrigerant stagnation does not occur in the outdoor heat exchanger. . According to this, by controlling the opening / closing operation of the on-off valve by the control unit, when it is predicted that the refrigerant will stagnate in the outdoor heat exchanger, the outdoor heat is extracted from the exhaust heat recovery side suction pipe. The refrigerant flow in the connecting pipe toward the exchanger-side suction pipe is blocked.

  Further, the valve member allows a refrigerant flow from the outdoor heat exchanger side suction pipe to the exhaust heat recovery side suction pipe, and from the exhaust heat recovery side suction pipe to the outdoor heat exchanger side suction pipe. It may be a check valve that blocks the flow of refrigerant toward the. According to this, the flow of the refrigerant in the connecting pipe heading from the exhaust heat recovery apparatus side suction pipe to the outdoor heat exchanger side suction pipe is reliably blocked by the check valve. Further, since the check valve does not need to be controlled, the engine-driven air conditioner can be configured at low cost.

It is the schematic which shows the whole structure of the engine drive type air conditioning apparatus which concerns on 1st Embodiment. It is a flowchart which shows the on-off valve control routine performed in order that an on-off valve control apparatus may control the opening / closing operation | movement of an on-off valve. It is the schematic which shows the whole structure of the engine drive type air conditioning apparatus which concerns on 2nd Embodiment. It is the schematic which shows the whole structure of the engine drive type air conditioning apparatus which concerns on 3rd Embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing an overall configuration of an engine-driven air conditioner according to a first embodiment of the present invention. As shown in FIG. 1, an engine-driven air conditioner 1 according to this embodiment includes a gas engine 11, a first compressor 12, a second compressor 13, a four-way switching valve 14, an indoor heat exchanger 15, The main components of the outdoor heat exchanger 16, the electronic expansion valves 17a and 17b, the engine exhaust heat recovery unit 18, the on-off valve 21, and the on-off valve control device 22 for controlling the on-off operation of the on-off valve 21. Prepare.

  The gas engine 11 is driven by burning fuel gas (for example, LPG). When the driving force of the gas engine 11 is transmitted to the first compressor 12 and the second compressor 13, the first compressor 12 and the second compressor 13 are driven. These compressors may be configured to be driven independently.

  The first compressor 12 and the second compressor 13 have suction ports 12a and 13a and discharge ports 12b and 13b, respectively, suck gas refrigerant from the suction ports 12a and 13a, and compress and compress the gas refrigerant inside. A high-temperature and high-pressure gas refrigerant is discharged from the discharge ports 12b and 13b.

  One end of the first pipe L1 is connected to the discharge port 12b of the first compressor 12, and one end of the second pipe L2 is connected to the discharge port 13b of the second compressor 13, respectively. The other end of the first pipe L1 and the other end of the second pipe L2 merge into a single third pipe L3 at point A in the figure. An oil separator 20 is interposed in the middle of the third pipe L3.

  The third pipe L3 is connected to the four-way switching valve 14. The four-way switching valve 14 includes a first port 14a, a second port 14b, a third port 14c, and a fourth port 14d. The first port 14a and the second port 14b communicate with each other, and the third port 14c and the fourth port It is configured to be switchable between a heating switching position where 14d communicates and a cooling switching position where the first port 14a and the fourth port 14d communicate and the second port 14b and the third port 14c communicate. The third pipe L3 is connected to the first port 14a of the four-way switching valve 14.

  One end of a fourth pipe L4 is connected to the second port 14b of the four-way switching valve 14. The other end of the fourth pipe L4 is connected to the suction port 15a of the indoor heat exchanger 15. The indoor heat exchanger 15 supplies refrigerant from the suction port 15a and exchanges heat between the supplied refrigerant and indoor air. Then, the heat-exchanged refrigerant is discharged from the discharge port 15b.

  The fifth pipe L5 is connected to the discharge port 15b of the indoor heat exchanger 15. The fifth pipe L5 branches into a sixth pipe L6 and a seventh pipe L7 at point B in the figure. The sixth pipe L6 is connected to the intake port 16a of the outdoor heat exchanger 16, and the seventh pipe L7 is connected to the engine exhaust heat recovery unit 18. An electronic expansion valve 17a is interposed in the middle of the sixth pipe L6, and an electronic expansion valve 17b is interposed in the middle of the seventh pipe L7. The electronic expansion valves 17a and 17b are configured so that their opening degrees can be adjusted. The refrigerant expands when it passes through the electronic expansion valves 17a and 17b.

  The outdoor heat exchanger 16 has a suction port 16a and a discharge port 16b. The refrigerant is supplied from the suction port 16a and exchanges heat with the outside air. Then, the heat-exchanged refrigerant is discharged from the discharge port 16b.

  The engine exhaust heat recovery unit 18 includes a refrigerant circulation pipe 181 and a cooling water circulation pipe 182. A refrigerant suction port 181a and a refrigerant discharge port 181b are formed in the refrigerant flow pipe 181. The seventh pipe L7 is connected to the refrigerant suction port 181a. Therefore, the refrigerant is supplied from the seventh pipe L7 side into the refrigerant circulation pipe 181 through the refrigerant intake port 181a. The supplied refrigerant flows through the refrigerant flow pipe 181 and is discharged from the refrigerant discharge port 181b. Further, the cooling water flow pipe 182 is formed with a cooling water suction port 182a and a cooling water discharge port 182b. Cooling water that has cooled the gas engine is supplied to the cooling water circulation pipe 182 from the cooling water intake port 182a. The supplied cooling water flows in the cooling water flow pipe 182. At this time, heat exchange with the refrigerant flowing through the refrigerant flow pipe 181 is performed. The cooling water flowing through the cooling water circulation pipe 182 is discharged from the cooling water discharge port 182b and returns to the gas engine 11 side.

  One end of an eighth pipe L8 is connected to the discharge port 16b of the outdoor heat exchanger 16. The other end of the eighth pipe L8 is connected to the fourth port 14d of the four-way switching valve 14. The third port 14c of the four-way switching valve 14 is connected to one end of the ninth pipe L9. The other end of the ninth pipe L9 is connected to the accumulator 19. The accumulator 19 is a device that separates liquid refrigerant and gas refrigerant. The accumulator 19 is formed with a refrigerant suction port 19a and a refrigerant discharge port 19b, and the other end of the fourth pipe L9 is connected to the refrigerant suction port 19a. On the other hand, the refrigerant discharge port 19b is connected to one end of the tenth pipe L10. The other end of the tenth pipe L10 is connected to the suction port 12a of the first compressor 12. As can be seen from FIG. 1, the outdoor heat exchanger 16 and the eighth pipe L8, the ninth pipe L9, and the tenth pipe L10 are connected to the outdoor heat exchanger 16 so that the refrigerant discharged from the outdoor heat exchanger 16 is sucked into the first compressor 12. A first compressor 12 is connected. The eighth pipe L8, the ninth pipe L9, and the tenth pipe L10 correspond to the outdoor heat exchanger side suction pipe of the present invention.

  One end of the eleventh pipe L11 is connected to the refrigerant discharge port 181b formed in the refrigerant flow pipe 181 of the engine exhaust heat recovery device 18. The other end of the eleventh pipe L11 is connected to the suction port 13a of the second compressor 13. As can be seen from FIG. 1, the engine exhaust heat recovery device 18 and the second compressor 13 are connected by the eleventh pipe L11 so that the refrigerant discharged from the engine exhaust heat recovery device 18 is sucked into the second compressor 13. Is done. The eleventh pipe L11 corresponds to the exhaust heat recovery device side suction pipe of the present invention.

  Further, the tenth pipe L10 (outdoor heat exchanger side suction pipe) and the eleventh pipe L11 (exhaust heat recovery side suction pipe) are connected by a twelfth pipe L12 (connection pipe). An on-off valve 21 (valve member) is interposed in the middle of the twelfth pipe L12. The on / off valve 21 is electrically connected to the on / off valve control device 22, and its opening / closing operation is controlled based on an open / close command signal from the on / off valve control device 22.

  In addition, a first temperature sensor 23a is attached to a position near the suction port 12a of the first compressor 12 in the tenth pipe L10, and a second temperature is located near the suction port 13a of the second compressor 13 in the eleventh pipe L11. A sensor 23b is attached. The first temperature sensor 23a detects the temperature (refrigerant intake temperature) T1 of the gas refrigerant sucked into the first compressor 12, and the second temperature sensor 23a detects the temperature of the gas refrigerant (refrigerant intake temperature) sucked into the second compressor 13. T2) is detected. Signals representing the temperatures detected by these sensors are output to the on-off valve control device 22. Further, a third temperature sensor 23 c is installed in the vicinity of the outdoor heat exchanger 16. The third temperature sensor 23c detects an outside air temperature T3 in the vicinity of the outdoor heat exchanger 16. A signal indicating the temperature detected by the third temperature sensor 23 c is output to the on-off valve control device 22.

  In the engine-driven air conditioner 1 having the above configuration, the operation during heating will be described below.

  When the gas engine 11 is driven, the first compressor 12 and the second compressor 13 are driven. When the first compressor 12 is driven, the first compressor 12 sucks the gas refrigerant from the suction port 12a, compresses the sucked gas refrigerant, and discharges it from the discharge port 12b as a high-temperature and high-pressure gas refrigerant. The discharged high-temperature and high-pressure gas refrigerant flows through the first pipe L1. When the second compressor 13 is driven, the second compressor 13 sucks the gas refrigerant from the suction port 13a, compresses the sucked gas refrigerant, and discharges it from the discharge port 13b as a high-temperature and high-pressure gas refrigerant. The discharged high-temperature and high-pressure gas refrigerant flows through the second pipe L2.

  The high-temperature and high-pressure gas refrigerant flowing through the first pipe L1 and the high-temperature and high-pressure gas refrigerant flowing through the second pipe L2 merge at the point A, and further supplied to the oil separator 20 through the third pipe L3. The oil separator 20 separates oil mixed in the gas refrigerant. The separated oil is returned to the accumulator 19 and used for lubricating the first compressor 12 and the second compressor 13. The high-temperature and high-pressure gas refrigerant from which the oil has been separated by the oil separator 20 is further introduced into the four-way switching valve 14 from the first port 14a of the four-way switching valve 14. Since the first port 14a and the second port 14b of the four-way switching valve 14 communicate with each other during heating, the refrigerant gas introduced into the four-way switching valve 14 from the first port 14a is discharged from the second port 14b.

  The high-temperature and high-pressure refrigerant gas discharged from the second port 14b of the four-way switching valve 14 is supplied to the indoor heat exchanger 15 from the suction port 15a of the indoor heat exchanger 15 through the fourth pipe L4. The high-temperature and high-pressure gas refrigerant supplied to the indoor heat exchanger 15 is condensed by exchanging heat with indoor air. The condensed gas refrigerant changes into a low-temperature and high-pressure gas-liquid two-phase refrigerant. At this time, the room is heated by discharging heat into the room in the process of condensation of the refrigerant in the room heat exchanger 15. The refrigerant that has flowed through the indoor heat exchanger 15 is discharged from the discharge port 15 b of the indoor heat exchanger 15. The discharged refrigerant flows through the fifth pipe L5.

  The refrigerant in the fifth pipe L5 is divided at point B into a refrigerant flowing through the sixth pipe L6 and a refrigerant flowing through the seventh pipe L7. The refrigerant flowing through the sixth pipe L6 passes through the electronic expansion valve 17a. When passing, the refrigerant expands to a low temperature and low pressure state, and then is supplied to the outdoor heat exchanger 16 from the suction port 16 a of the outdoor heat exchanger 16. In the outdoor heat exchanger 16, the low-temperature and low-pressure gas-liquid two-phase refrigerant evaporates by exchanging heat with the outside air. At this time, heat is taken from the outside air in the process of evaporating the refrigerant in the outdoor heat exchanger 16. Thereafter, the refrigerant in the outdoor heat exchanger 16 is discharged from the discharge port 16b. The discharged refrigerant flows through the eighth pipe L8.

  The gas-liquid two-phase refrigerant flowing through the eighth pipe L8 is introduced from the fourth port 14d of the four-way switching valve 14 to the four-way switching valve 14. Since the third port 14c and the fourth port 14d communicate with each other during heating, the gas-liquid two-phase refrigerant introduced from the fourth port 14d to the four-way switching valve 14 is discharged from the third port 14c. The discharged gas-liquid two-phase refrigerant passes through the ninth pipe L9 and is sucked into the accumulator 19 from the refrigerant suction port 19a. The refrigerant sucked into the accumulator 19 is separated into a gas refrigerant and a liquid refrigerant, and only the gas refrigerant is sucked into the tenth pipe L10 and flows through the tenth pipe L10.

  On the other hand, the low-temperature and high-pressure gas-liquid two-phase refrigerant flowing out of the indoor heat exchanger 15 and flowing through the fifth pipe L5 and the seventh pipe L7 is expanded by passing through the electronic expansion valve 17b, and thus the low-temperature and low-pressure gas-liquid two Further, the refrigerant is supplied to the refrigerant circulation pipe 181 from the refrigerant suction port 181a of the refrigerant circulation pipe 181 of the engine exhaust heat recovery device 18. Then, the refrigerant flows in the refrigerant flow pipe 181. The gas-liquid two-phase refrigerant in the refrigerant flow pipe 181 is heated by the cooling water flowing through the cooling water flow pipe 182 to be a low-temperature and low-pressure gas refrigerant. And it discharges from the refrigerant | coolant discharge port 181b. In addition, the opening degree of the electronic expansion valve 17b is adjusted so that the gas-liquid two-phase refrigerant completely changes into the gas refrigerant in the engine exhaust heat recovery unit 18. The gas refrigerant discharged from the engine exhaust heat recovery device 18 flows through the eleventh pipe L11.

  As described above, the tenth pipe L10 and the eleventh pipe L11 are connected by the twelfth pipe L12. Therefore, when the on-off valve 21 interposed in the twelfth pipe L12 is open, the gas refrigerant flowing through the tenth pipe L10 is directly sucked into the suction port 12a of the first compressor 12, or It is introduced into the eleventh pipe L11 through the twelfth pipe L12 and sucked into the suction port 13a of the second compressor 13. Similarly, the refrigerant flowing through the eleventh pipe L11 is supplied to the suction port 13a of the second compressor 13 as it is, or introduced into the tenth pipe L10 through the twelfth pipe L12, and the suction port 12a of the first compressor 12 is supplied. Inhaled. On the other hand, when the on-off valve 21 is closed, all of the gas refrigerant flowing through the tenth pipe L10 is sucked into the suction port 12a of the first compressor 12, and all of the gas refrigerant flowing through the eleventh pipe L11 is drawn into the second compressor. The air is sucked into thirteen suction ports 13a.

  The above is the basic operation of the engine-driven air conditioner 1 during heating. During cooling, the switching position of the four-way switching valve 14 is switched to the cooling switching position. Therefore, the refrigerant from the first and second compressors 12 and 13 is first supplied to the outdoor heat exchanger 16 and condensed, and then supplied to the indoor heat exchanger 15 and evaporated. The room is cooled by removing heat from the room when the refrigerant evaporates. The refrigerant discharged from the outdoor heat exchanger 16 is supplied to the indoor heat exchanger 15 through the bypass pipe L13 without passing through the electronic expansion valve 17a in order to reduce pressure loss.

  During the operation of the engine-driven air conditioner 1, the on-off valve controller 22 acquires temperature information detected by the first temperature sensor 23a, the second temperature sensor 23b, and the third temperature sensor 23c, and based on the acquired temperature information. The opening / closing operation of the opening / closing valve 21 is controlled. FIG. 2 is a flowchart showing an on / off valve control routine executed by the on / off valve control device 22 to control the opening / closing operation of the on / off valve 21. The on-off valve control device 22 repeatedly executes the on-off valve control routine every predetermined short time during the operation of the engine-driven air conditioner 1.

  When this on-off valve control routine starts, first, the on-off valve control device 22 performs the heating operation of the current engine-driven air conditioner 1 in step (hereinafter, step number is abbreviated as S) 101 in FIG. Judge whether or not. When it is not the heating operation (S101: No), that is, for example, when it is the cooling operation, the on-off valve control device 22 advances the process to S107 and outputs a valve opening signal to the on-off valve 21. As a result, the on-off valve 21 is opened. When the on-off valve 21 is already open, that state is maintained. Thereafter, the on-off valve control device 22 once ends this routine. Therefore, the opening / closing valve 21 is always open when not in the heating operation (for example, in the cooling operation).

  When it is determined that the heating operation is performed in S101 (S101: Yes), the on-off valve controller 22 acquires the refrigerant suction temperature T1 detected by the first temperature sensor 23a in S102, and then the second in S103. The refrigerant suction temperature T2 detected by the temperature sensor 23b is acquired, and further, the outside air temperature T3 detected by the third temperature sensor 23c is acquired in S104. Subsequently, the on-off valve control device 22 determines whether or not the liquid refrigerant stagnates in the outdoor heat exchanger 16 based on the acquired temperatures (S105). In this case, the on-off valve control device 22 may determine whether or not the liquid refrigerant has stagnation based on the fact that the liquid refrigerant stagnates more easily in the outdoor heat exchanger 16 as the outside air temperature is lower, for example. For example, it may be determined that stagnation occurs when the outside air temperature T3 is equal to or lower than a predetermined temperature (for example, minus 20 degrees or less), and may be determined that stagnation does not occur when the temperature is higher than a predetermined temperature. Alternatively, the on-off valve control device 22 may determine whether or not there is stagnation based on the high possibility that stagnation has occurred in the outdoor heat exchanger 16 when the refrigerant suction temperature is high. For example, it may be determined that stagnation occurs when the average temperature T of the refrigerant suction temperature T1 and the refrigerant suction temperature T2 is equal to or higher than a threshold temperature, and may be determined that stagnation does not occur when the average temperature T is lower than the threshold temperature. Incidentally, when stagnation occurs, the density of the refrigerant circulating in the refrigerant circuit decreases. When the density of the refrigerant decreases, for example, the temperature rises greatly when the refrigerant is heated with oil (refrigeration oil) mixed in the refrigerant pipe. For this reason, when stagnation occurs, the temperature of the refrigerant sucked into the compressor and the temperature of the refrigerant discharged from the compressor tend to increase.

  When the on-off valve controller 22 determines in S105 that the liquid refrigerant does not stagnate in the outdoor heat exchanger 16 (S105: No), the process proceeds to S107, and a valve-opening signal is output to the on-off valve 21. . As a result, the on-off valve 21 is opened. When the on-off valve 21 is already open, that state is maintained. Thereafter, the on-off valve control device 22 once ends this routine. On the other hand, when it is determined that stagnation occurs (S105: Yes), the on-off valve control device 22 proceeds to S106 and outputs a valve-closing signal to the on-off valve 21. Thereby, the on-off valve 21 is closed. When the on-off valve 21 is already closed, that state is maintained. Thereafter, the on-off valve control device 22 once ends this routine.

  When the on-off valve control device 22 executes the above-described on-off valve control routine, the on-off valve 21 is closed when the stagnation is predicted to occur, and the on-off valve 21 is opened when the stagnation is not predicted to occur.

  By the way, the outside air temperature is low during cold seasons such as winter when the engine-driven air conditioner 1 is heating. The outdoor heat exchanger 16 evaporates the refrigerant by pumping heat from outside air having a low temperature and exchanging heat with the refrigerant inside. In general, since the evaporation temperature of the refrigerant is considerably low (for example, minus 20 degrees), even if the outside air temperature is very low (for example, about minus 15 degrees), the refrigerant can be evaporated by pumping heat from the outside air. Even if the outside air temperature is extremely low (for example, about minus 25 degrees), the refrigerant pressure in the outdoor heat exchanger 16 is adjusted by adjusting the flow rate of the refrigerant flowing in the outdoor heat exchanger 16 by the electronic expansion valve 17a. If the temperature is reduced, heat can be pumped from the outside air to evaporate the refrigerant.

  However, in addition to the outdoor heat exchanger, an apparatus for evaporating the refrigerant, specifically, an engine exhaust heat recovery device is provided, and the outdoor heat exchanger and the engine exhaust heat recovery device are connected in the refrigerant circuit. In this case, the relatively high pressure of the refrigerant in the engine exhaust heat recovery unit affects the refrigerant pressure in the outdoor heat exchanger. Therefore, even if the flow rate of the refrigerant flowing through the outdoor heat exchanger is adjusted by the electronic expansion valve when the outside air temperature is extremely low, the refrigerant pressure in the outdoor heat exchanger is affected by the refrigerant pressure in the engine exhaust heat recovery unit. The refrigerant pressure in the outdoor heat exchanger cannot be reduced to a pressure at which it can easily evaporate. Therefore, the refrigerant cannot be evaporated by the outdoor heat exchanger. In addition, the refrigerant evaporation capacity of the engine exhaust heat recovery unit exceeds the refrigerant evaporation capacity of the outdoor heat exchanger, and the heat of the refrigerant in the outdoor heat exchanger is taken away by the outside air, so that the outdoor heat exchanger is more than an evaporator. Rather, it may function as a condenser. Then, a phenomenon that liquid refrigerant accumulates in the outdoor heat exchanger, that is, stagnation occurs. When the stagnation occurs, the amount of refrigerant circulating in the refrigerant circuit decreases, causing a situation where the refrigerant operation is insufficient and the heating operation cannot be performed. Such a situation in which stagnation occurs can occur when the outside air temperature T3 is extremely low as described above. Further, when the stagnation occurs, the refrigerant suction temperatures T1 and T2 tend to increase.

  In the present embodiment, when it is predicted that a stagnation will occur (S105: Yes), the on-off valve 21 is closed. When the on-off valve 21 is closed, the flow of the refrigerant in the twelfth pipe from the eleventh pipe L11 to the tenth pipe L10 is blocked, and the inside of the twelfth pipe from the tenth pipe L10 to the eleventh pipe L11. The flow of refrigerant at is blocked. Therefore, the refrigerant flowing through the outdoor heat exchanger 16 is sucked into the suction port 12a of the first compressor 12 via the eighth pipe L8-four-way switching valve 14-ninth pipe L9-accumulator 19-tenth pipe. The On the other hand, the refrigerant that has flowed through the refrigerant flow pipe 181 of the engine exhaust heat recovery device 18 is sucked into the suction port 13a of the second compressor 13 via the eleventh pipe L11. That is, the refrigerant flowing through the outdoor heat exchanger 16 and the refrigerant flowing through the engine exhaust heat recovery unit 18 are sucked into separate compressors.

  With such a refrigerant circuit configuration, the refrigerant flowing through the outdoor heat exchanger 16 is sucked into the first compressor 12 and the refrigerant flowing through the engine exhaust heat recovery unit 18 is sucked into the second compressor 13. The distribution route until it is released is separated. As a result of the separation of the two flow paths, the refrigerant on the engine exhaust heat recovery unit 18 side is prevented from moving toward the outdoor heat exchanger 16 side. This prevents the refrigerant pressure in the engine exhaust heat recovery unit 18 from affecting the refrigerant pressure in the outdoor heat exchanger 16. Therefore, by adjusting the flow rate of the refrigerant flowing through the outdoor heat exchanger 16 by the electronic expansion valve 17a, the refrigerant easily evaporates in the outdoor heat exchanger 16 without worrying about the refrigerant pressure in the engine exhaust heat recovery unit 18. Thus, the refrigerant pressure in the outdoor heat exchanger 16 can be reduced. As a result, even when the outside air temperature is extremely low, the outdoor heat exchanger 16 functions normally as an evaporator, and the refrigerant evaporates in the outdoor heat exchanger 16. Since the refrigerant evaporates in the outdoor heat exchanger 16, the liquid refrigerant does not accumulate in the outdoor heat exchanger 16. That is, no sleep occurs. As described above, in the present embodiment, even when the outside air temperature is extremely low, the outdoor heat exchanger 16 can be normally operated as an evaporator to evaporate the refrigerant in the outdoor heat exchanger 16, and the outdoor heat exchanger 16 can be evaporated. The stagnation of the liquid refrigerant in the heat exchanger 16 can be prevented.

  FIG. 3 is a schematic diagram showing the overall configuration of the engine-driven air conditioner 2 according to the second embodiment. The difference between the engine-driven air conditioner 2 and the engine-driven air conditioner 1 described in the first embodiment is that a check valve 24 is installed in the twelfth pipe L12 instead of an on-off valve. And the on-off valve control apparatus 22 with which the engine drive type air conditioning apparatus 1 which concerns on 1st Embodiment is provided is not provided. Since other configurations are the same as those of the engine-driven air conditioner 1 according to the first embodiment, the same configurations are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

  As described above, the check valve 24 is interposed in the twelfth pipe L12 of the engine-driven air conditioner 2. This check valve 24 allows the refrigerant to flow in the twelfth pipe L12 from the tenth pipe L10 toward the eleventh pipe L11, and in the twelfth pipe L12 from the eleventh pipe L11 toward the tenth pipe L10. Block the refrigerant flow at

  Since the flow of the refrigerant in the twelfth pipe L12 from the tenth pipe L10 toward the eleventh pipe L11 is allowed, the refrigerant is discharged from the outdoor heat exchanger 16 and the eighth pipe L8-four-way switching valve 14-ninth. The refrigerant flowing into the tenth pipe L10 via the pipe L9-accumulator 19 reaches the eleventh pipe L11 through the twelfth pipe L12 and the refrigerant sucked into the suction port 12a of the first compressor 12 as it is. To the refrigerant sucked into the suction port 13a of the second compressor 13. On the other hand, since the refrigerant flow in the twelfth pipe L12 from the eleventh pipe L11 toward the tenth pipe L10 is blocked by the check valve 24, the refrigerant flow pipe 181 of the engine exhaust heat recovery device 18 is The flowing refrigerant is sucked into the suction port 13a of the second compressor 13 via the eleventh pipe L11. That is, the refrigerant flowing through the engine exhaust heat recovery unit 18 is sucked only into the second compressor 13 and is not sucked into the first compressor 12.

  When the outside air temperature is extremely low, the electronic expansion valve 17a is throttled to reduce the flow rate of the refrigerant flowing through the outdoor heat exchanger 16, and the refrigerant pressure in the outdoor heat exchanger 16 is lowered. However, when the refrigerant circuit configuration is such that a relatively high refrigerant pressure in the engine exhaust heat recovery unit 18 acts on the refrigerant pressure in the outdoor heat exchanger 16, the refrigerant pressure in the outdoor heat exchanger 16 is evaporated. It is difficult to reduce to an easy pressure. On the other hand, in the engine-driven air conditioner 2 according to the present embodiment, the refrigerant on the eleventh pipe L11 side, that is, the engine exhaust heat recovery unit 18 side is provided by the check valve 24 interposed in the twelfth pipe L12. However, it is blocked | prevented from distribute | circulating to the 10th piping L10 side, ie, the outdoor heat exchanger 16 side. For this reason, the refrigerant pressure on the engine exhaust heat recovery unit 18 side does not affect the refrigerant pressure in the outdoor heat exchanger 16.

  Therefore, by adjusting the flow rate of the refrigerant flowing through the outdoor heat exchanger 16 by the electronic expansion valve 17a, the refrigerant easily evaporates in the outdoor heat exchanger 16 without worrying about the refrigerant pressure in the engine exhaust heat recovery unit 18. Thus, the refrigerant pressure in the outdoor heat exchanger 16 can be reduced. As a result, even when the outside air temperature is extremely low, the outdoor heat exchanger 16 functions normally as an evaporator, and the refrigerant evaporates in the outdoor heat exchanger 16. Since the refrigerant evaporates in the outdoor heat exchanger 16, the liquid refrigerant does not accumulate in the outdoor heat exchanger 16. That is, no sleep occurs. As described above, in the present embodiment, even when the outside air temperature is extremely low, the outdoor heat exchanger 16 can be normally operated as an evaporator to evaporate the refrigerant in the outdoor heat exchanger 16, and the outdoor heat exchanger 16 can be evaporated. The stagnation of the liquid refrigerant in the heat exchanger 16 can be prevented.

  Further, since the check valve does not need to be controlled, the check valve control device 22 shown in the first embodiment is not required. Therefore, the engine-driven air conditioner can be configured at a low cost.

  FIG. 4 is a schematic diagram showing the overall configuration of the engine-driven air conditioner 3 according to the third embodiment. The difference between the engine-driven air conditioner 3 and the engine-driven air conditioner 2 described in the second embodiment is that the ninth pipe L9 and the eleventh pipe L11 are connected by a fourteenth pipe L14. And the electronic expansion valve 25 is interposed in the 14th piping L14. Since other configurations are the same as those of the engine-driven air conditioner 1 according to the second embodiment, the same configurations are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

  According to the engine-driven air conditioner 3 according to the third embodiment, for example, when the outside air temperature is extremely low and it is predicted that stagnation will occur in the outdoor heat exchanger 16, it is interposed in the fourteenth pipe L14. The electronic expansion valve 25 is closed. When the electronic expansion valve 25 is closed, the refrigerant circuit shown in FIG. 4 is the same as the refrigerant circuit shown in FIG. 3, so that the same operational effects as the engine-driven air conditioner 2 according to the second embodiment are achieved. Further, by opening the electronic expansion valve 25 when it is not predicted that stagnation will occur, the refrigerant on the engine exhaust heat recovery unit 18 side can be sucked not only into the second compressor 13 but also into the first compressor 12.

  As described above, the engine-driven air conditioners 1, 2, and 3 of the present embodiment are driven by the gas engine 11 to suck in the refrigerant and compress and discharge the drawn refrigerant. A room that is provided indoors with the second compressor 13 and is supplied with refrigerant compressed by the first compressor 12 and the second compressor 13 during heating, and heat-exchanges the supplied refrigerant and indoor air to condense the refrigerant. Heat exchanger 15, electronic expansion valve 17a that expands the refrigerant discharged from indoor heat exchanger 15 during heating, and refrigerant that is provided outside and expanded by electronic expansion valve 17a during heating is supplied and supplied refrigerant The outdoor heat exchanger 16 that evaporates the refrigerant by exchanging heat with the outside air, and the refrigerant discharged from the indoor heat exchanger 15 during heating are supplied, and the supplied refrigerant The exhaust heat recovery unit 18 that exchanges heat with the engine coolant and the outdoor heat exchanger 16 and the first compressor 12 are connected so that the refrigerant discharged from the outdoor heat exchanger 16 is sucked into the first compressor 12. The exhaust heat from the outdoor heat exchanger (the eighth pipe L8, the ninth pipe L9, the tenth pipe L10) and the refrigerant discharged from the engine exhaust heat recovery unit 18 is sucked into the second compressor 13 An exhaust heat recovery side suction pipe (11th pipe L11) connecting the heat recovery unit 18 and the second compressor 13, and a connection pipe (external heat exchanger side intake piping and exhaust heat recovery side suction pipe) The twelfth pipe L12) and the connecting pipe, and at least when the refrigerant is expected to stagnate in the outdoor heat exchanger 16, the exhaust heat recovery side suction pipe is connected to the outdoor heat exchanger side suction pipe. The valve member (open-close valve 21, a check valve 24) for blocking the flow of refrigerant within the connection pipe towards equipped with a.

  According to the engine-driven air conditioners 1, 2, and 3 according to the present embodiment, when at least stagnation is predicted, the twelfth pipe L12 from the eleventh pipe L11 to the tenth pipe L10 is predicted. The refrigerant flow is interrupted. Since the 11th piping L11 is connected to the engine exhaust heat recovery unit 18 and the 10th piping L10 is connected to the outdoor heat exchanger 16, when the occurrence of stagnation is predicted, the engine exhaust heat is generated by the valve member. The refrigerant in the recovery unit 18 is prevented from moving toward the outdoor heat exchanger 16 side. This prevents the refrigerant pressure in the engine exhaust heat recovery unit 18 from affecting the refrigerant pressure in the outdoor heat exchanger 16. Therefore, by adjusting the flow rate of the refrigerant supplied to the outdoor heat exchanger 16 by the electronic expansion valve 17a, the refrigerant in the outdoor heat exchanger 16 can be obtained without worrying about the refrigerant pressure in the engine exhaust heat recovery unit 18. Thus, the refrigerant pressure in the outdoor heat exchanger 16 can be reduced so that is easily evaporated. As a result, even if the outside air temperature at which stagnation is predicted to be extremely low, the outdoor heat exchanger 16 can function normally as an evaporator and the refrigerant can be evaporated in the outdoor heat exchanger 16. . Further, since the refrigerant is evaporated in the outdoor heat exchanger 16, it is possible to prevent liquid refrigerant from sleeping in the outdoor heat exchanger 16.

  Further, according to the engine-driven air conditioner 1 according to the first embodiment, the opening / closing valve 21 is interposed in the twelfth pipe L12, and the opening / closing valve 21 is controlled to open / close by the opening / closing valve control device 22. . The on-off valve control device 22 determines whether or not refrigerant stagnation occurs in the outdoor heat exchanger 16 based on the refrigerant suction temperatures T1 and T2 or the outside air temperature T3. The on-off valve 21 is closed when it is determined that the refrigerant stagnation occurs, and the on-off valve 21 is opened when it is determined that the refrigerant does not stagnate in the outdoor heat exchanger 16. 21 is controlled. Therefore, when the stagnation of the refrigerant in the outdoor heat exchanger 16 is predicted to occur, the refrigerant flow in the twelfth pipe L12 from the eleventh pipe L11 to the tenth pipe L10 can be surely cut off. it can.

  Further, according to the engine-driven air conditioners 2 and 3 according to the second and third embodiments, the check valve 24 is interposed in the twelfth pipe L12. The refrigerant flow in the twelfth pipe L12 from the pipe L10 to the eleventh pipe L11 is allowed, and the refrigerant flow in the twelfth pipe L12 from the eleventh pipe L11 to the tenth pipe L10 is blocked. That is, the check valve 24 always blocks the flow of the refrigerant in the twelfth pipe L12 from the eleventh pipe L11 to the tenth pipe L10. Therefore, even when the outside air temperature is extremely low, the refrigerant flow is reliably blocked. Further, since the check valve does not need to be controlled, the engine-driven air conditioner can be configured at low cost.

  As mentioned above, although embodiment of this invention was described, this invention should not be limited to the said embodiment. For example, in the above-described embodiment, an example of recovering heat of engine cooling water as an engine exhaust heat recovery device has been shown, but exhaust heat of the engine may be recovered. In the above embodiment, an example in which it is determined whether or not stagnation occurs in the outdoor heat exchanger 16 based on the refrigerant suction temperatures T1 and T2 or the outside air temperature T3 has been described. It may be determined whether or not stagnation occurs based on the change caused by. Thus, the present invention can be modified without departing from the gist thereof.

1, 2, 3 ... Engine-driven air conditioner, 11 ... Gas engine, 12 ... First compressor, 12a ... Suction port, 12b ... Discharge port, 13 ... Second compressor, 13a ... Suction port, 13b ... Discharge port, 14 ... Four-way switching valve, 15 ... Indoor heat exchanger, 15a ... Suction port, 15b ... Discharge port, 16 ... Outdoor heat exchanger, 16a ... Suction port, 16b ... Discharge port, 17a ... Electronic expansion valve, 18 ... Engine exhaust Heat recovery unit, 181 ... refrigerant flow pipe, 181a ... refrigerant suction port, 181b ... refrigerant discharge port, 19 ... accumulator, 21 ... open / close valve (valve member), 22 ... open / close valve control device, 23a, 23b, 23c ... temperature sensor 24, check valve (valve member), L8, eighth pipe (outdoor heat exchanger side suction pipe), L9, ninth pipe (outdoor heat exchanger side suction pipe), L10 10 pipe (outdoor heat exchanger-side intake pipe), L11 ... 11th pipe (exhaust heat recovery device side intake pipe), L12 ... 12th pipe (connection pipe), T1, T2 ... refrigerant suction temperature, T3 ... outdoor temperature

Claims (4)

A first compressor and a second compressor that suck in the refrigerant by being driven by the engine and compress and discharge the sucked refrigerant;
An indoor heat exchanger that is provided indoors and is supplied with refrigerant compressed by the first compressor and the second compressor during heating, and heat-exchanges the supplied refrigerant and indoor air to condense the refrigerant;
An expansion valve for expanding the refrigerant discharged from the indoor heat exchanger during heating;
An outdoor heat exchanger that is provided outside and is supplied with refrigerant expanded by the expansion valve during heating, evaporates the refrigerant by exchanging heat between the supplied refrigerant and outside air,
The refrigerant discharged from the indoor heat exchanger during heating is supplied, and an engine exhaust heat recovery unit that exchanges heat between the supplied refrigerant and the exhaust heat of the engine,
An outdoor heat exchanger-side suction pipe connecting the outdoor heat exchanger and the first compressor so that the refrigerant discharged from the outdoor heat exchanger is sucked into the first compressor;
An exhaust heat recovery side suction pipe connecting the engine exhaust heat recovery unit and the second compressor so that the refrigerant discharged from the engine exhaust heat recovery unit is sucked into the second compressor;
A connecting pipe that connects the outdoor heat exchanger side suction pipe and the exhaust heat recovery side suction pipe;
The connection from the exhaust heat recovery side suction pipe to the outdoor heat exchanger side suction pipe when the refrigerant is expected to stagnate at least in the outdoor heat exchanger. A valve member for blocking the flow of refrigerant in the pipe;
An engine-driven air conditioner comprising: The engine-driven air conditioner according to claim 1,
The valve member is closed when it is predicted that refrigerant stagnation occurs in the outdoor heat exchanger, and is opened when it is predicted that refrigerant stagnation does not occur in the outdoor heat exchanger. An engine-driven air conditioner that is an on-off valve. The engine-driven air conditioner according to claim 2,
It is determined whether or not refrigerant stagnation occurs in the outdoor heat exchanger, and when it is determined that refrigerant stagnation occurs in the outdoor heat exchanger, the on-off valve is closed and the outdoor heat is An engine-driven air conditioner further comprising a control unit that controls the on-off valve so that the on-off valve is opened when it is determined that refrigerant stagnation does not occur in the exchanger. The engine-driven air conditioner according to claim 1,
The valve member allows a refrigerant to flow in the connection pipe from the outdoor heat exchanger side suction pipe to the exhaust heat recovery apparatus side suction pipe, and the outdoor heat exchange from the exhaust heat recovery apparatus side suction pipe. An engine-driven air conditioner, which is a check valve that blocks the flow of refrigerant in the connection pipe toward the container-side suction pipe.

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