JP4799347B2 - Hot water supply, cold and hot water air conditioner - Google Patents

Description

  The present invention relates to hot water supply and cold / hot water air conditioners.

  There are many conventional technologies for hot water supply and cold / hot water air conditioners.

  FIG. 13 is a simplified diagram of the prior art refrigerant circuit disclosed in Patent Document 1. In FIG. As shown in FIG. 13, the refrigerant circuit includes an outdoor unit refrigerant circuit and a water circuit. The outdoor unit refrigerant circuit is composed of a compressor 1, a four-way valve 2, a water refrigerant heat exchanger 3, a pressure reducing device 4, an outdoor heat exchanger 6, an outdoor fan 7, and an outdoor fan motor 8. The water circuit is a water pump 21, three-way. It comprises a valve 22, a hot water supply tank 23, a tank internal heat exchanger 24, and a cold / hot water air conditioning heat exchanger 25.

Next, the operation of the refrigerant and water in each operation mode of the prior art will be described with reference to FIG.
In the case of hot water supply operation, in the outdoor unit refrigerant circuit, the high-pressure high-temperature gas refrigerant discharged from the compressor 1 flows into the water-refrigerant heat exchanger 3 through the four-way valve 2, where the heat is supplied to the load unit and condensed. And flows out as a high-pressure liquid refrigerant. The high-pressure liquid refrigerant that has flowed out is decompressed by the decompression device 4 to become a low-pressure gas-liquid two-phase refrigerant, flows into the outdoor heat exchanger 6 where the outdoor fan 7 is forcibly blowing air, and exchanges heat with ambient air to evaporate. It flows out as a low-pressure gas refrigerant. The low-pressure gas refrigerant that has flowed out returns to the compressor 1 via the four-way valve 2.

  When the defrost operation is performed during the hot water supply operation or the hot water heating operation, in the outdoor unit refrigerant circuit, the high-pressure high-temperature gas refrigerant discharged from the compressor 1 flows into the outdoor heat exchanger 6 in which the outdoor fan 7 is stopped via the four-way valve 2. In this case, heat is exchanged with the frost attached to the heat exchanger to condense and flow out as a high-pressure liquid refrigerant. The high-pressure liquid refrigerant that has flowed out flows into the water-refrigerant heat exchanger 3 via the decompression device 4 that is fully open, where it absorbs heat from the load-side system, evaporates, and flows out as low-pressure gas refrigerant. The low-pressure gas refrigerant that has flowed out returns to the compressor 1 via the four-way valve 2.

JP 05-340641 A (FIG. 1, paragraphs 0024 to 0034)

  In the prior art disclosed in Patent Document 1, there is a problem that the ability recovery of the hot water supply operation and the hot water heating operation after the defrost operation is slow. In the initial stage of the defrost operation, the amount of frost on the outside of the outdoor heat exchanger 6 is large and the amount of heat exchange of the outdoor heat exchanger 6 is large. Therefore, the refrigerant flowing through the outdoor heat exchanger 6 is immediately condensed and liquefied. The amount of liquid refrigerant staying in the outdoor heat exchanger 6 is large. On the other hand, at the end of the defrosting operation, since there is no frost outside the pipe of the outdoor heat exchanger 6, the amount of heat exchange in the outdoor heat exchanger 6 is small, so that the refrigerant flowing through the outdoor heat exchanger 6 hardly condenses, The amount of liquid refrigerant staying in the heat exchanger 6 is reduced. The refrigerant flowing out of the outdoor heat exchange air stays in the accumulator 10.

  The liquid refrigerant staying in the outdoor heat exchanger 6 at the initial stage of the defrost operation flows out of the outdoor heat exchanger 6 and stays in the accumulator 10 when the defrost operation approaches. In the separate air conditioner in which the condenser and the evaporator are air-cooled heat exchangers and the outdoor unit and the indoor unit are connected by an extension pipe, the refrigerant flowing out of the outdoor heat exchanger 6 is not only in the accumulator 10 but also in the extension pipe. Stay. On the other hand, since the hot water supply and cold / hot water air conditioner do not have an extension pipe, most of the refrigerant flowing out of the outdoor heat exchanger 6 stays in the accumulator 10.

  When the defrost operation is terminated and the hot water supply operation or the hot water heating operation is started, the capacity does not increase unless the refrigerant accumulated in the accumulator 10 is moved to the water refrigerant heat exchanger 3 to increase the high pressure. However, a large amount of energy is required to move the refrigerant staying in the low-pressure accumulator 10 to the high-pressure water-refrigerant heat exchanger, and it takes time to move especially at low outside air temperatures. In order to move the refrigerant from the accumulator 10 to the water refrigerant heat exchanger, the refrigerant at the inlet of the accumulator needs to be in a superheated gas state, and contact heat is exchanged with the accumulated liquid in the accumulator 10 to evaporate the accumulated refrigerant. The superheated gas refrigerant at the inlet of the accumulator becomes a saturated gas refrigerant after contact heat exchange.

  The time required for 0.5 kg of the liquid refrigerant in the accumulator 10 to evaporate and flow out of the accumulator 10 is calculated and examined. When the refrigerant used is R410A and the physical property calculation at 0 ° C is calculated using the refrigerant property calculation program REFPROPver.7, the latent heat L at 0 ° C is 221.3kJ / kg, and the superheat Qsh at 10 ° C at 0 ° C saturated gas pressure is 10.8 kJ / kg. The amount of heat E required to evaporate 0.5 kg of the 0 ° C. refrigerant in the accumulator 10 is 110.7 kJ (= L × 0.5 kg). When the refrigerant flow rate Gr at the start of hot water supply and hot water heating operation is 1.6 kg / min and the degree of superheat of the refrigerant at the accumulator inlet is 10 ° C., the contact heat exchange amount Q with the liquid refrigerant in the accumulator 10 is 17.3 kJ / min (= (Gr × Qsh), it can be calculated by calculation that it takes 6.4 minutes (= E / Q) to evaporate 0.5 kg of refrigerant. In addition to this, since the accumulator 10 after the defrost operation is cold, it is necessary to heat the accumulator 10 with the superheat energy of the gas refrigerant, and the refrigerant state is unstable for several minutes after the start of hot water supply and hot water heating operation. Considering that it is difficult to overheat the accumulator inlet refrigerant, it takes at least 10 minutes. Thus, in hot water supply operation and hot water heating operation after defrost operation, it takes time until the capacity increases.

Further, the conventional technique has a technical problem that the capacity is reduced during a refrigeration cycle high compression ratio operation such as a high temperature hot water supply operation under a low outside air temperature. The reason is as follows.
It is obvious that the temperature of the compressor discharge refrigerant and the state of the compressor intake refrigerant are highly correlated, and the temperature of the compressor discharge refrigerant can be controlled by controlling the degree of superheat and dryness of the compressor intake refrigerant.
Further, when surplus refrigerant is generated in the refrigerant circuit, the surplus refrigerant stays in the accumulator 10. If the refrigerant stays in the accumulator 10, the state of the compressor suction refrigerant is stabilized at a dryness of 0.8 to 1, so that it is difficult to freely control the state of the compressor suction refrigerant. Since the suction state of the compressor cannot be freely controlled, the compressor discharge refrigerant temperature cannot be easily controlled.

  Actually, when the temperature of the refrigerant discharged from the compressor exceeds the reliability upper limit value, control for lowering the discharge temperature by lowering the compressor operating frequency is introduced instead of controlling the refrigerant state of the compressor suction. This will reduce your ability.

  In a separate air conditioner (hereinafter referred to as a normal air conditioner) in which the condenser and the evaporator are air-cooled heat exchangers and the outdoor unit and the indoor unit are connected by an extension pipe, the blowing temperature required during heating operation is It is around 50 ° C at the highest. On the other hand, in hot water operation, the required hot water temperature is often 60 ° C or higher. In the hot water supply and hot water heating air conditioner, it is necessary to control the discharge temperature of the compressor more freely than in the heating operation of the separate air conditioner. In the prior art, there are many cases where the compressor operating frequency is reduced and the capacity is lowered by limiting the discharge temperature as compared with a normal air conditioner.

  The present invention has been made to solve the above-mentioned problems, and the capacity of hot water supply and hot water heating operation after defrost operation has risen quickly, and the capacity is improved during refrigeration cycle high compression ratio operation such as low outdoor air high temperature hot water supply operation. It aims at providing the hot water supply which does not fall, and a cold / hot water air conditioning apparatus.

In order to solve the above-mentioned problems, a hot water supply and cold / hot water air conditioner of the present invention is provided in an outdoor unit, a compressor having a variable rotation speed of a refrigerant, a four-way valve, a first heat exchanger that exchanges heat with water, Water comprising a refrigerant circuit that sequentially circulates a second heat exchanger that exchanges heat with air, a water transfer means, and a hot water supply tank, and water sequentially circulates through the water transfer means, the first heat exchanger , and the hot water supply tank A circuit, two pressure reducing devices provided in series in a pipe communicating the first heat exchanger and the second heat exchanger, a receiver provided between the two pressure reducing devices and storing refrigerant, and a control And the control means fully opens the opening of the two decompression devices during the defrost operation in which the refrigerant circulates in the direction opposite to the direction of the circulation , and immediately before the defrost operation ends, the control means Open the decompression device on the downstream side while keeping the opening of the decompression device on the upstream side fully open. The pressure reducing device on the upstream side is controlled to be small and the outlet supercooling degree of the heat exchanger serving as a condenser in the first and second heat exchangers becomes a predetermined target value during hot water supply and hot water heating operation. And the opening of the decompression device on the downstream side is controlled based on the compressor discharge temperature or the compressor discharge superheat degree.

  According to the present invention, it is possible to provide hot water supply and chilled / hot water air conditioners that have quick rise in capacity for hot water supply and hot water heating operation after defrost operation, and that do not have reduced performance during refrigeration cycle high compression ratio operation such as low outside air high temperature hot water supply operation. .

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below.

  FIG. 1 shows a refrigerant circuit diagram. The refrigerant circuit is composed of an outdoor unit refrigerant circuit and a water circuit. The outdoor unit refrigerant circuit includes a compressor 1, a four-way valve 2, a water refrigerant heat exchanger 3, decompression devices 4 a and 4 b, a receiver 5, an air-cooled outdoor heat exchanger 6, an outdoor fan 7, and an outdoor fan motor 8. The water circuit includes a water pump 21, a hot water supply tank 23, and a tank internal heat exchanger 24. Further, on the outdoor unit side, the outdoor unit ambient dry bulb temperature detecting means 31, the water refrigerant heat exchanger inlet water temperature detecting means 32, the liquid pipe side refrigerant temperature detecting means 33 of the air-cooled heat exchanger, the water refrigerant heat exchanger. The liquid pipe side refrigerant temperature detecting means 34, the compressor discharge temperature detecting means 35, and the compressor discharge pressure detecting means 36 are attached. A load-side control / communication means 41 for controlling each component of the water circuit, and an outdoor unit control and communication means 42 for controlling each component of the outdoor unit refrigerant circuit and the outdoor unit are provided.

  In FIG. 1, reference numeral 24 indicates the heat exchanger type in the tank internal heat exchanger, but the same function can be obtained by a double structure type or other type as shown in FIG. The same effect can be obtained from FIG.

  The outdoor unit control / communication means 42 constitutes a control means, the water-refrigerant heat exchanger 3 constitutes a first heat exchanger, and the air-cooled outdoor heat exchanger 6 constitutes a second heat exchanger. To do.

  FIG. 3 shows a refrigerant circuit diagram. The refrigerant circuit of the outdoor unit includes a compressor 1, a four-way valve 2, a water refrigerant heat exchanger 3, decompression devices 4 a and 4 b, a receiver 5, an air-cooled heat exchanger 6, an outdoor fan 7, and an outdoor fan motor 8. The water circuit includes a water pump 21 and a heat exchanger 25 for cold / hot water air conditioner. On the outdoor unit side, the outdoor unit ambient dry bulb temperature detecting means 31 includes an inlet water temperature detecting means 32 for the water refrigerant heat exchanger, a liquid pipe side refrigerant temperature detecting means 33 for the air-cooled heat exchanger, and water refrigerant heat exchange. A liquid pipe side refrigerant temperature detecting means 34, a compressor discharge temperature detecting means 35, and a compressor discharge pressure detecting means 36 are attached, and load side control / communication means for controlling each component of the water circuit. 41, and an outdoor unit control and communication means 42 for controlling each component of the outdoor unit refrigerant circuit and the outdoor unit.

  FIG. 4 shows a refrigerant circuit diagram. The refrigerant circuit of the outdoor unit includes a compressor 1, a four-way valve 2, a water refrigerant heat exchanger 3, decompression devices 4 a and 4 b, a receiver 5, an air-cooled heat exchanger 6, an outdoor fan 7, and an outdoor fan motor 8. The water circuit includes a water pump 21, a three-way valve 22, a hot water supply tank 23, a tank internal heat exchanger 24, and a heat exchanger 25 for a cold / hot water air conditioner. On the outdoor unit side, the outdoor unit ambient dry bulb temperature detecting means 31 includes an inlet water temperature detecting means 32 for the water refrigerant heat exchanger, a liquid pipe side refrigerant temperature detecting means 33 for the air-cooled heat exchanger, and water refrigerant heat exchange. A liquid pipe side refrigerant temperature detecting means 34, a compressor discharge temperature detecting means 35, and a compressor discharge pressure detecting means 36 are attached, and load side control / communication means for controlling each component of the water circuit. 41, and an outdoor unit control and communication means 42 for controlling each component of the outdoor unit refrigerant circuit and the outdoor unit.

  1, 3, and 4, the load side control / communication means 41, the water pump 21, and the three-way valve 22 are connected by a wired or wireless communication line (not shown). The outdoor unit control and communication means 42 are the motor rotation control means of the compressor 1, the four-way valve 2, the pressure reducing devices 4a and 4b, the rotation speed control means of the outdoor fan motor 8, and the temperature / pressure detection means (31 to 36). Are connected by a wired or wireless communication line (not shown). The load side unit control / communication means 41 and the outdoor unit control / communication means 42 are connected by a wired or wireless communication line (not shown). Each of the refrigerant circuits in FIG. 5 and subsequent figures includes temperature detection means, pressure detection means (31 to 36), load side unit control / communication means 41, outdoor unit control, and communication means 42, which are similarly connected by communication lines. Description is omitted.

Next, the operation of the refrigerant and water in each operation mode will be described with reference to FIG.
In the case of hot water supply operation, in the outdoor unit refrigerant circuit, the high-pressure high-temperature gas refrigerant discharged from the compressor 1 flows into the water-refrigerant heat exchanger 3 through the four-way valve 2, where the heat is supplied to the load unit and condensed. And flows out as a high-pressure liquid refrigerant. The high-pressure liquid refrigerant that has flowed out is decompressed by the decompression device 4a and becomes a medium-pressure saturated liquid refrigerant and flows into the decompression device 4b through the receiver 5, where it is decompressed and becomes a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant flows into the outdoor heat exchanger 6 forcibly blown by the outdoor fan 7, where it evaporates by exchanging heat with ambient air and flows out as a low-pressure gas refrigerant. The low-pressure gas refrigerant that has flowed out returns to the compressor 1 via the four-way valve 2.

  In the hot water supply operation, in the load side unit, the water discharged from the water pump 21 flows into the water / refrigerant heat exchanger 3 where the water temperature is received from the outdoor unit and the water temperature rises. It flows into the tank internal heat exchanger 24 provided in the inside. Here, hot water is supplied to the water in the tank to lower the water temperature and return to the water pump 21. By switching the three-way valve 22, water does not circulate in the heat exchanger 25 for cold / hot water air conditioning.

  When the hot water heating operation is performed, the refrigerant operation of the outdoor unit refrigerant circuit is the same as the hot water supply operation, and thus the description thereof is omitted. When performing the hot water heating operation, in the load side unit, the water discharged from the water pump 21 flows into the water-refrigerant heat exchanger 3, where the water temperature is received from the outdoor unit to increase the water temperature, and cold water is supplied via the three-way valve 22. It flows into the air conditioner heat exchanger 25. Here, heat is exchanged with the ambient air to lower the water temperature, and the water pump 21 is returned. Water is not circulated to the tank internal heat exchanger 24 provided in the hot water supply tank 23 by switching the three-way valve 22.

  In the case of the cold water cooling operation, in the refrigerant circuit of the outdoor unit, the high-pressure high-temperature gas refrigerant discharged from the compressor 1 flows into the outdoor heat exchanger 6 forcibly ventilated by the outdoor fan 7 through the four-way valve 2. It exchanges heat with ambient air, condenses, and flows out as a high-pressure liquid refrigerant. The high-pressure liquid refrigerant that has flowed out is decompressed by the decompression device 4b and becomes a medium-pressure saturated liquid refrigerant and flows into the decompression device 4a through the receiver 5, where it is decompressed and becomes a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant flows into the water-refrigerant heat exchanger 3, where cold heat is supplied to the load side unit to evaporate, and flows out as low-pressure gas refrigerant. The low-pressure gas refrigerant that has flowed out returns to the compressor 1 via the four-way valve 2.

  In the cold water cooling operation, in the load side unit, the water discharged from the water pump 21 flows into the water / refrigerant heat exchanger 3 where the cold water is received from the outdoor unit and the water temperature is lowered. It flows into the air conditioner heat exchanger 25. Here, the cooling air is supplied to the ambient air, the water temperature rises, and the water pump 21 is returned. Water is not circulated to the tank internal heat exchanger 24 provided in the hot water supply tank 23 by switching the three-way valve 22.

A refrigerant circuit control procedure during operation will be described.
As a first step, the operation command and required capacity are transmitted from the load side control / communication means 41 to the outdoor unit control / communication means 42.
As a second step, the outdoor unit control / communication means 42 collects values detected by the temperature / pressure detection means (31-36).
As a third step, the outdoor unit control / communication unit 42 includes the required capacity, the outdoor unit ambient dry bulb temperature detected by the outdoor unit ambient dry bulb temperature detection unit 31, and the inlet water temperature detection unit 32 of the water-refrigerant heat exchanger. The rotation speed of the compressor motor is determined from the detected water refrigerant heat exchanger water inlet temperature. If the relationship between the three values is mapped in advance, the determination time can be shortened.
As a fourth step, the outdoor unit control / communication unit 42 determines the outdoor unit fan motor rotation speed from the outdoor unit ambient dry bulb temperature detected by the outdoor unit ambient dry bulb temperature detection unit 31.
As a fifth step, the outdoor unit control / communication means 42 calculates the condenser saturated liquid temperature from the compressor discharge pressure detected by the compressor discharge pressure detection means 36 during hot water supply and hot water heating operation, and the water refrigerant heat exchanger The outlet refrigerant subcooling degree of the water refrigerant heat exchanger, which is a condenser, is obtained from the value of the liquid pipe connection port temperature of the water refrigerant heat exchanger detected by the liquid pipe side refrigerant temperature detecting means 34, and the obtained subcooling degree is obtained. The opening degree of the decompression device 4a communicating with the water-refrigerant heat exchanger 3 is determined so that the value becomes a predetermined target value. The outdoor unit control / communication means 42 calculates the condenser saturated liquid temperature from the compressor discharge pressure detected by the compressor discharge pressure detection means 36 during the cold water cooling operation, and the liquid pipe side refrigerant of the air-cooled heat exchanger The degree of refrigerant subcooling at the outlet of the air-cooled heat exchanger, which is a condenser, is obtained from the value of the liquid pipe connection port temperature of the air-cooled heat exchanger detected by the temperature detection means 33, and the obtained degree of supercooling is a predetermined target. The opening degree of the decompression device 4b communicating with the air-cooled heat exchanger 6 is determined so as to be a value.
As a sixth step, the outdoor unit control / communication means 42 sends the compressor motor rotational speed determined in the third to fifth steps to the compressor motor rotational speed control unit (not shown), and the outdoor fan motor rotational speed to the outdoor unit. A decompression device opening degree is transmitted to a decompression device opening degree control unit (not shown) and controlled to a fan motor rotation speed control unit (not shown). This control is performed every predetermined time. The predetermined time is set to a value between 20 seconds and 2 minutes in consideration of the stability of the refrigeration cycle.

The water circuit control procedure during operation will be described. It is assumed that the water pump 21 can switch the motor rotation speed to two stages. Several stages can be switched.
As a first step, the load side control / communication means 41 determines whether or not to request an operation from the outdoor unit.
As a second step, the load-side control / communication means 41 determines the motor rotation speed of the water pump 21 to be a predetermined minimum rotation speed when no operation request is made to the outdoor unit. Here, the necessary minimum motor rotation speed is a rotation speed for obtaining a flow rate necessary for preventing water in the circuit from freezing even when the ambient temperature of the water circuit is less than 0 ° C. When making an operation request to the outdoor unit, the load-side control / communication means 41 determines the motor rotation speed of the water pump 21 to a rotation speed that is not a predetermined minimum rotation speed.
As a third step, the presence / absence of the operation command and the required capacity on the load side are transmitted from the load side control / communication means 41 to the outdoor unit control / communication means 42.

  In the hot water supply and cold / hot water air conditioner, it will be described that the technical problem caused by the conventional combination circuit of one decompression device and an accumulator can be solved by the combination circuit of the two decompression devices and the receiver of the present invention.

Technical issues In the accumulator circuit, the startup is slow when switching from defrost operation to hot water supply or hot water heating operation.

  Since the defrosting operation in the accumulator circuit, the hot water supply after the completion of the defrosting operation, the refrigerant operation and the problem during the hot water heating operation have been described in the problem to be solved by the invention, they are omitted here.

  The refrigerant operation during the defrost operation in the combination circuit of the two decompression devices and the receiver will be described with reference to FIG. Since the defrost operation causes the refrigerant to flow in the same direction as in the cold water cooling operation, it is often called a reverse method. The high-pressure and high-temperature gas refrigerant discharged from the compressor 1 in the refrigerant circuit flows into the air-cooled exchanger 6 where the outdoor fan 7 is stopped via the four-way valve 2, and exchanges heat with frost on the surface of the heat exchanger 6. The frost is melted by the heat of condensation and the refrigerant flows out as a high-pressure liquid refrigerant. The high-pressure liquid refrigerant that has flowed out flows into the water-refrigerant heat exchanger 3 through the decompression device 4b, the receiver 5, and the decompression device 4a that are fully open, where they absorb heat from the water circuit side and evaporate to flow out as low-pressure gas refrigerant. To do. The low-pressure gas refrigerant that has flowed out returns to the compressor 1 via the four-way valve 2.

  At the time of defrost operation, if the opening degree of the two decompression devices is maximized, the refrigerant flow rate is increased and the defrost operation time can be shortened. Therefore, the opening degree of the decompression device is basically maximized. However, if the opening of the two decompression devices is maintained at the maximum even when the defrost operation is almost over, the frost on the surface of the air-cooled heat exchanger has almost melted, and the air-cooled heat exchanger 6 remains in the air-cooled heat exchanger 6. The amount of the liquid refrigerant is reduced in a short time, and in a short time and in a large amount to the compressor suction side via the receiver 5, the pressure reducing device 4 a communicating with the water refrigerant heat exchanger 3, the water refrigerant heat exchanger 3, and the four-way valve 2. Come back. Due to this liquid back phenomenon, the refrigeration oil concentration in the compressor is diluted to below the lower limit of reliability, which may cause a compressor failure.

  Therefore, when the opening of the decompression device 4a communicating with the water-refrigerant heat exchanger 3 is set to be small just before the end of the defrost operation, the liquid refrigerant flowing out from the air-cooled heat exchanger 6 is retained in the receiver 5 and sent to the compressor. The amount of liquid back can be reduced.

When the defrosting operation is terminated and the hot water supply or hot water heating operation is started, if the opening of the decompression device 4b communicating with the air-cooled heat exchanger is set to be small, the refrigerant staying in the receiver 5 is briefly transferred to the compressor. And it can prevent returning in large quantities.
On the other hand, at the time of hot water supply or hot water heating, it is necessary to move the refrigerant staying in the receiver 5 to the water refrigerant heat exchanger to increase the discharge pressure. There are a decompressor 4b, an air-cooled heat exchanger 6, a four-way valve 2, a compressor 1, and a four-way valve 2 in the middle of the water-refrigerant heat exchanger 3 from the receiver 5; Complete in time.

  As described above, in the conventional hot water supply and cold / hot water air conditioner of the accumulator circuit, it takes time to move the liquid refrigerant accumulated in the accumulator at the end of the defrost operation from the accumulator to the water refrigerant heat exchanger at the start of hot water supply and hot water heating. However, in the circuit of the present invention having two pressure reducing devices and a receiver, the two pressure reducing devices are opened at the time of switching from the end of the defrost operation to the hot water supply and hot water heating operation. The amount of liquid back to the compressor is reduced while accumulating liquid refrigerant in the receiver during defrost operation, and the refrigerant transfer from the receiver to the water refrigerant heat exchanger is completed in a short time when hot water supply or hot water heating starts. Therefore, it is possible to start hot water supply and hot water heating operation immediately.

  Further, since the two pressure reducing devices are controlled separately with target values, the rise time is shortened.

  Technical problem 2. In the accumulator circuit, it is necessary to reduce the compressor frequency and reduce the heat capacity during refrigeration cycle high compression ratio operation such as high-temperature hot water supply operation at low outside air temperature.

  Since the refrigerant operation and problems in the accumulator circuit have been described in the problem to be solved by the invention, they are omitted here.

A control method of the decompression device when hot water supply or hot water heating operation is performed by a combination circuit of two decompression devices and a receiver will be described. The outdoor unit control communication means 42 controls the opening degree of the decompression device 4a communicating with the water refrigerant heat exchanger 3 so that the outlet refrigerant subcooling degree of the water refrigerant heat exchanger 3 becomes a target value. Specifically, the outdoor unit control communication unit 42 calculates a saturated liquid temperature CTl from the compressor discharge pressure detected by the discharge pressure detection unit 36, and uses this to calculate the saturated liquid of the outlet refrigerant of the water refrigerant heat exchanger 3. Consider temperature. Next, the outdoor unit control communication means 42 determines the difference ΔTc between the saturated liquid temperature CTl and the temperature Tco detected by the liquid refrigerant side refrigerant temperature detection means 34 of the water refrigerant heat exchanger 3 (of the water refrigerant heat exchanger 3). The outlet refrigerant supercooling degree) is obtained by the following equation, and the opening degree of the decompression device 4a is controlled so that this value becomes a predetermined target value.
ΔTc = CT1-Tco

The outdoor unit control communication means 42 controls the opening of the decompression device 4b communicating with the outdoor heat exchanger 6 so that the compressor discharge temperature or the degree of superheat of the compressor discharge refrigerant becomes a target value. Specifically, the outdoor unit control communication unit 42 controls the opening degree of the decompression device 4b so that the discharge temperature Td of the compressor detected by the discharge temperature detection unit 35 becomes a predetermined target value. Alternatively, the outdoor unit control communication means 42 calculates the saturated gas temperature CTg from the compressor discharge pressure detected by the discharge pressure detection means 36, and then detects the saturation gas temperature CTg and the discharge temperature detection means 35. A difference ΔTd (degree of superheat of the refrigerant discharged from the compressor) with respect to the temperature Td is obtained by the following equation, and the opening degree of the decompression device 4b is controlled so that this value becomes a predetermined target value.
ΔTd = Td−CTg
Since there is no container in which refrigerant accumulates on the compressor suction side, the temperature of the compressor discharge refrigerant can be freely controlled by controlling the opening of the decompression device 4b. At that time, the compressor suction refrigerant state also changes.

  When the supply hot water temperature rises and the temperature of the refrigerant discharged from the compressor exceeds the reliability upper limit value, the outdoor unit control communication means 42 opens the opening of the decompression device 4b communicating with the outdoor heat exchanger. By controlling and reducing the dryness of the refrigerant sucked from the compressor, the temperature of the refrigerant discharged from the compressor can be made lower than the reliability upper limit value. At this time, since the outdoor unit control communication means 42 does not reduce the compressor operating frequency, it can ensure the high temperature heat capacity.

  The outdoor unit control communication means 42 can control the pressure reducing device 4a communicating with the water refrigerant heat exchanger 3 so that the liquid refrigerant subcooling degree at the outlet of the water refrigerant heat exchanger becomes a target value. The required pressure is maintained by the refrigerant flowing through the refrigerant, and the necessary refrigerant amount can be secured in the water refrigerant heat exchanger 3. As a result, it is possible to improve reliability by supplying a high capacity and forming an appropriate refrigerant distribution in the refrigeration cycle.

Next, the merit of employing a plate heat exchanger for the water refrigerant heat exchanger 3 will be described.
First, it will be explained that the plate type heat exchanger is smaller when the air-cooled fin tube type heat exchanger is compared with the heat transfer area and refrigerant side volume.

In the finned tube heat exchanger, the refrigerant circulates inside the pipe, and the wind forced from the fan circulates outside the pipe. The wind speed outside the tube is designed at 1-2 m / sec in consideration of noise and the like, and the heat transfer coefficient αo outside the tube is less than 100 W / m2K. When the heat transfer coefficient outside the tube is 100 W / m2K, the heat transfer coefficient αi in the tube is 5000 W / m2K, and the ratio Ao / Ai between the tube outside area Ao and the tube inside area Ai is 20, the heat transfer rate K of the condenser is expressed by equation (1) From the above value, K = 71.4 W / m2K.
1 / K = (1 / αo + (Ao / Ai) / αi) Equation (1)

  Next, a plate heat exchanger is assumed as the water refrigerant heat exchanger. In a plate heat exchanger, a plurality of plates are stacked, and refrigerant and water flow alternately between them. The heat transfer coefficient of water is 1000-10000W / m2K. When the water-side heat transfer coefficient αo is 1000 W / m2K, the refrigerant-side heat transfer coefficient αi is 5000 W / m2K, and the ratio Ao / Ai between the water-side area Ao and the refrigerant-side area Ai is 1, the heat transfer coefficient K of the condenser is ( It can be obtained from equation (1), and K = 833.3W / m2K when calculated using the above value. Even if the water-refrigerant heat exchanger is of a double tube type or has a shape in which a refrigerant copper tube is wound around the water-copper tube, the heat transfer rate is almost the same value.

  Therefore, the plate-type water-refrigerant heat exchanger has a heat passing rate of about 10 times or more with respect to the air-cooled fin tube heat exchanger. Since the heat exchange performance can be obtained by the product of the heat transfer area and the heat transfer rate, in the case of the same heat exchange performance, the heat transfer area may be 1/10 when the heat transfer rate is increased 10 times. Therefore, the plate type heat exchanger can reduce the heat transfer area with respect to the air-cooled fin tube heat exchanger.

  The refrigerant side volume of the air-cooled fin tube heat exchanger and the plate heat exchanger is compared. The capacity of the air-cooled finned tube heat exchanger installed in the four-way cassette type indoor unit with a rated capacity of 9kW is 1.5L, and the plate type heat exchanger equivalent to the rated capacity of 9kW (Alpha Laval ACH30 (trademark) plate The volume on the refrigerant side of 30 sheets is 0.8L. Therefore, the refrigerant volume of the plate heat exchanger can be reduced with respect to the air-cooled fin tube heat exchanger.

Next, the merit obtained by using a plate heat exchanger will be described.
(1) Quick start-up at the start of hot water supply and hot water heating operation
(2) Since the plate-type heat exchanger has a small internal volume, a small amount of refrigerant can be retained. When hot water supply and hot water heating operation are started up in a short time after the defrost operation is completed, it is necessary to move the necessary amount of refrigerant from the receiver to the plate heat exchanger that is a water refrigerant heat exchanger in a short time. Since the plate type heat exchanger requires a smaller amount of refrigerant movement than the plate fin type heat exchanger, the time required for starting up the capacity can be shortened. It has already been explained that this is possible because the circuit includes two pressure reducing devices.
(3) Stabilization of refrigerant state at the inlet of the decompression device The decompression device has a characteristic that control is not guaranteed unless the state of the inlet refrigerant is a complete liquid state. Therefore, when a plate fin heat exchanger is used for the condenser, a control for ensuring the liquid refrigerant state is introduced by introducing a control for ensuring the degree of supercooling of the inlet refrigerant of the decompression device of 4 deg or more. On the other hand, when performing hot water supply or hot water heating operation, if the outlet refrigerant supercooling degree of the water refrigerant heat exchanger connected to the upstream side of the decompression device is increased, the condensation temperature rises (FIG. 12) and the operation efficiency decreases. When supplying high-temperature water, the reliability upper limit pressure of the apparatus may be exceeded, so the outlet refrigerant supercooling degree of the water refrigerant heat exchanger should be as small as possible. When a plate type heat exchanger is used and the refrigerant is allowed to flow from top to bottom, it is possible to make the liquid refrigerant free from bubbles even if the degree of subcooling at the outlet is small due to the characteristics of the structure of the heat exchanger. Specifically, it was confirmed by experiments that a liquid refrigerant without bubbles can be secured even at a supercooling degree of 2 deg.

  The structure of the compressor will be described. A rotary compressor may be applied to the refrigerant circuit of the present invention. Since the compression chamber of the rotary compressor has no valve at the discharge port, it does not become overcompressed. Therefore, it is strong against liquid back compared to scroll type and reciprocating type. Further, it is well known that the operation efficiency with respect to the compression ratio has less fluctuation in the rotary type than in the scroll type.

  In the refrigerant circuit of the present invention, since there is no refrigerant retention container on the compressor suction side, the liquid back amount can be reduced by controlling the pressure reducing device when the operation mode is switched, but it cannot be reduced to zero. In addition, the operating temperature conditions are wider than those of ordinary air conditioners. For example, according to the specification of Mitsubishi Electric Packaged Air Conditioner 5HP MPLZ-WRP140BED (trademark), the room temperature is specified as 17 to 28 ° C and the outdoor temperature is set as -20 to 21 ° C. On the other hand, as an example of hot water supply operation, warm water is 10 to 60 ° C., outdoor temperature is -20 to 43 ° C., and it can be seen that the operation temperature conditions are wide. As a result, the compression ratio range of the refrigeration cycle is widened. Under such conditions, the scroll compressor is over-compressed in a low compression ratio operation, resulting in a reduction in operating efficiency and reliability. On the other hand, in the case of high compression ratio operation, the compression chamber becomes undercompressed, resulting in a decrease in operating efficiency and reliability. Considering the above, it is better to apply a rotary compressor.

  In the case of applying the scroll compressor, it is preferable to employ a compressor having a valve or the like for releasing the refrigerant in the compression chamber to the outside of the compression chamber when the compression chamber in the closed space becomes overcompressed.

  When a scroll compressor is applied, it is preferable to employ a compressor having a structure that communicates with the suction pipe and does not perform compression work until the compressor crankshaft rotates to a certain angle.

  The compressor may be of a scroll type provided with a suction unload mechanism capable of capacity control.

Next, the refrigerant charging amount will be described. In a normal air conditioner, the amount of refrigerant required for cooling operation and heating operation is obtained, and the larger amount is determined as the amount of charged refrigerant, but the amount of charged refrigerant determined by this method is insufficient for the defrost operation.
For example, when taking the refrigerant circuit of air-cooled heat exchanger 4L and plate-type heat exchanger 1L as an example, the amount of refrigerant required for hot water supply and hot water heating is 1.0 g, and the amount of refrigerant required for cold water cooling is 1.8 kg. When 1.8 kg is used as the charging refrigerant amount, an experiment is conducted in which almost all refrigerant amount stays in the air-cooled heat exchanger during the defrost operation, and the refrigerant amount that circulates in the refrigerant circuit decreases because the refrigerant amount stays on the low-pressure side becomes too small. I understood. During defrost operation, about 1/2 medium of air-cooled heat exchanger volume stays at 0 ℃. Therefore, the refrigerant weight when the 0 ° C. saturated liquid refrigerant occupies about half of the volume of the air-cooled heat exchanger is set as the required minimum charge refrigerant quantity, and a value larger than this value is actually set as the charge refrigerant quantity. In the case of the R410A refrigerant, the 0 ° C. saturated liquid density is 1170 kg / m 3, and the necessary minimum charge refrigerant amount is 1170 kg / m 3 × 4 L / 1000 × 1/2 = 2.34 kg. Therefore, 1.04 kg (2.84-1.8 = 1.04 kg) of refrigerant is insufficient during the defrost operation.

  Next, the refrigerant used will be described. In the device according to the present invention, the degree of supercooling at the outlet of the condenser is controlled, and therefore it is necessary that the gas-liquid two-phase refrigerant is always circulated in the condenser. FIG. 12 shows an example of the temperature distribution of the refrigerant and water in the water-refrigerant heat exchanger during hot water supply operation. Whether the water outlet temperature or the gas-liquid two-phase refrigerant temperature is higher is determined by the specifications of the water refrigerant heat exchanger. If the heat exchange performance is high, the water outlet temperature is higher, and if the heat exchange performance is low, the water outlet temperature is lower.However, if the critical point temperature of the refrigerant is 5 ° C or higher than the water outlet temperature, There is definitely a means to generate a two-phase refrigerant state. For example, if R410A is used as the refrigerant, the critical temperature is 72.1 ° C, so if the water outlet temperature of the highest water refrigerant heat exchanger is 65 ° C, the critical point temperature of the refrigerant is 7.1 ° C higher than the water outlet temperature, 5 ° C or more Since the condition of high is satisfied, the gas-liquid two-phase refrigerant state can be generated by the water refrigerant heat exchanger, and the control of the apparatus of the present invention can be applied.

  Next, the effect of estimating the outdoor unit ambient wet bulb temperature during hot water supply and hot water heating operation will be described below. Even when the outdoor ambient dry bulb temperature is 30 ° C, the wet bulb temperature varies depending on the weather. For example, the wet bulb temperature can be less than 20 ° C for sunny weather and 28 ° C for rain. It also depends on the circumstances of the outdoor unit installation location. For example, when the air-cooled heat exchanger 6 is used in an evaporator, when heat is exchanged with ambient air, mass transfer occurs that cools and liquefies the surrounding water vapor. Therefore, the refrigerant evaporation temperature with respect to the same heat exchange amount differs depending on the amount of water vapor present around. When the amount of water vapor is large, that is, when the wet bulb temperature is high, the amount of mass transfer in the amount of heat exchange increases, so the evaporation temperature of the refrigerant circuit increases. Considering the above, it can be easily understood that it is effective to detect the wet bulb temperature around the outdoor unit, but the wet bulb temperature sensor is expensive, and the accuracy is guaranteed when the wet bulb temperature sensor is used outdoors. There is a problem that you can not.

Therefore, in the present invention device, a method for estimating the wet bulb temperature from the refrigerant state of the refrigerant circuit and correcting the compressor motor rotation speed has been presented. A specific control procedure will be described.
As the first step, the outdoor unit control / communication unit 42 includes the required capacity received from the load side control / communication unit 41, the calculated outdoor unit ambient dry bulb temperature, the liquid refrigerant temperature detection unit of the water refrigerant heat exchanger. The compressor motor rotation speed calculated from the water inlet temperature of the water refrigerant heat exchanger detected by 34 is determined. This value is the basic rotation speed.
As a second step, the outdoor unit control / communication unit 42 determines the basic wet bulb temperature from the outdoor unit ambient dry bulb temperature detected by the outdoor unit ambient dry bulb temperature detection unit 31. The basic wet bulb temperature is set and mapped in advance in a one-to-one relationship with the outdoor unit ambient dry bulb temperature with reference to, for example, weather data for the past 30 years in Tokyo.
As a third step, the outdoor unit control / communication means 42 calculates the basic refrigerant evaporation temperature of the refrigerant circuit from the required capacity received from the load side control / communication means 41 and the basic wet bulb temperature determined in the second step. The relationship between the required capacity, the wet bulb temperature and the refrigerant evaporation temperature is set and mapped in advance with reference to the test results and simulation calculation results.
As a fourth step, the outdoor unit control / communication means 42 compares the basic refrigerant evaporating temperature with the liquid pipe side refrigerant temperature of the air-cooled heat exchanger during actual operation, and determines whether there is a difference greater than a predetermined temperature difference. To do. The predetermined temperature difference is preferably 1 ° C. in consideration of sensor error.
As a fifth step, if the difference is within the predetermined temperature, the correction value is set to zero. When the temperature difference is not less than the predetermined temperature difference, it is determined that the wet bulb temperature around the actual outdoor unit is different from the basic wet bulb temperature. In such a case, the calculated outdoor unit ambient dry bulb temperature is calculated from the calculated outdoor unit ambient wet bulb temperature using a map, and the required capacity, calculated outdoor unit ambient dry bulb temperature, water refrigerant heat exchanger liquid is calculated. The calculated compressor motor rotation speed is determined from the water inlet temperature of the water refrigerant heat exchanger detected by the pipe side refrigerant temperature detecting means 34. Compressor motor rotation speed is uniquely determined by using a map created by quantifying the relationship between required capacity, calculated outdoor unit ambient dry bulb temperature, and water refrigerant heat exchanger water inlet temperature in advance development tests. To decide.
A value obtained by multiplying the difference between the basic rotational speed and the calculated rotational speed by a coefficient is added as a correction value to the basic rotational speed.

  Since the accuracy of the calculated wet bulb temperature around the outdoor unit is not necessarily high, a coefficient is applied to the difference between the basic rotational speed and the calculated rotational speed. In addition, by performing the operation at regular intervals, such as every 10 minutes, the low accuracy is reflected in the control, thereby avoiding large fluctuations in the rotational speed.

Next, when performing hot water supply and heating / heating operations, when the inlet water temperature of the water-refrigerant heat exchanger 3 is equal to or lower than a predetermined temperature, in order to improve the reliability of the refrigerant circuit, the refrigerant outlet subcooling degree of the plate heat exchanger If the inlet water temperature is higher than the case where the inlet water temperature is equal to or higher than the predetermined temperature, the condensing pressure increases and the operating range of the refrigerant circuit can be kept within the reliability guarantee range. For example, the predetermined temperature of the inlet water temperature is 20 ° C., and the degree of supercooling is 2 deg.
In order to improve the reliability of the refrigerant circuit even when hot water supply or hot water heating operation is performed and the dry bulb temperature around the outdoor unit falls below a predetermined temperature, the refrigerant outlet subcooling degree of the plate heat exchanger If the inlet water temperature is higher than the case where the inlet water temperature is equal to or higher than the predetermined temperature, the condensing pressure increases and the operating range of the refrigerant circuit can be kept within the reliability guarantee range. For example, the predetermined temperature of the outdoor unit ambient dry bulb temperature is −10 ° C., and the degree of supercooling is 2 deg.
In either case, the condensing pressure is increased to ensure the minimum guaranteed compression ratio of the compressor and to keep the operating range of the refrigerant circuit within the guaranteed range.

  The water flow rate in the water circuit is set to 1.5 m / sec as the minimum flow rate so as not to cause pitting corrosion in the pipe. The water flow rate when the outdoor unit is not in operation is also 1.5 m / sec.

Embodiment 2. FIG.
Next, another apparatus configuration will be described.
FIG. 5 is a refrigerant circuit diagram of the hot water supply and cold / hot water air conditioner according to Embodiment 2 of the present invention.
5, a water circuit is added to the water circuit via a cold / hot water air conditioner-like heat exchanger 25 in FIG. 4, and the water circuit is changed to a ground heat exhaust heat exchanger 26 instead of the air-cooled heat exchanger 6. Is. Thereby, the hot water supply using geothermal heat and a cold / hot water air conditioner are realizable. By exhausting the exhaust heat of the outdoor unit into the ground where the temperature is stable throughout the year, the refrigerant distribution in the outdoor unit refrigerant circuit can be stabilized, and as a result, the reliability of the refrigerant circuit is ensured. can do.

Embodiment 3 FIG.
Another device configuration will be described.
FIG. 6 is a refrigerant circuit diagram of the hot water supply and cold / hot water air conditioner in Embodiment 2 of the present invention.
As shown in FIG. 6, the refrigerant circuit includes a compressor 1, a four-way valve 2, a water / refrigerant heat exchanger 3, decompression devices 4 a and 4 b, a receiver 5, an outdoor heat exchanger 6, an outdoor fan 7, and an outdoor fan motor 8. The water circuit includes a water pump 21, a three-way valve 22, a hot water supply tank 23, a water pump 27, and a water / water heat exchanger 28.
6, in the refrigerant circuit of FIG. 4, instead of removing the tank internal heat exchanger 24 from the hot water supply tank 23, a water circuit is added via a water / water heat exchanger 28, and a water pump 27 is added to the water circuit. Is provided.

  Description of refrigerant and water operations is omitted. When this system is employed, the tank internal heat exchanger 24 in the hot water tank is not necessary, and the structure of the hot water tank can be simplified. Further, when a malfunction occurs in the water / water heat exchanger (tank internal heat exchanger) 28, it is difficult to replace the tank internal heat exchanger 24, but there is an advantage that the water / water heat exchanger 28 is easily replaced. .

Embodiment 4 FIG.
Another device configuration will be described.
FIG. 7 shows a refrigerant circuit provided with an internal heat exchanger for exchanging heat between the refrigerant in the receiver and the refrigerant between the outdoor heat exchanger and the compressor in the combination circuit of the two decompression devices and the receiver.

FIG. 7 is a refrigerant circuit diagram of the hot water supply and cold / hot water air conditioner in Embodiment 4 of the present invention.
As shown in FIG. 7, the refrigerant circuit includes a compressor 1, a four-way valve 2, a water / refrigerant heat exchanger 3, decompression devices 4 a and 4 b, a receiver 5, an outdoor heat exchanger 6, an outdoor fan 7, an outdoor fan motor 8, The internal heat exchanger 9 in the receiver includes a water pump 21, a three-way valve 22, a hot water supply tank 23, a tank internal heat exchanger 24, and a cold / hot water air conditioner heat exchanger 25.
FIG. 7 shows a configuration in which a receiver internal heat exchanger 9 is added inside the receiver 5 in the refrigerant circuit of FIG. 4.

Next, the operation of the refrigerant and water in each operation mode will be described with reference to FIG.
In the case of hot water supply operation, in the outdoor unit refrigerant circuit, the high-pressure high-temperature gas refrigerant discharged from the compressor 1 flows into the water-refrigerant heat exchanger 3 through the four-way valve 2, where the heat is supplied to the load unit and condensed. And flows out as a high-pressure liquid refrigerant. The high-pressure liquid refrigerant that has flowed out is reduced in pressure by the decompression device 4a and becomes a medium-pressure liquid-rich gas-liquid two-phase refrigerant and flows into the receiver 5, and the low-pressure gas that circulates in the pipe by the internal heat exchanger 9 in the receiver 5. Heat exchange with the refrigerant condenses, flows out as a saturated liquid refrigerant, is decompressed by the decompression device 4b, and becomes a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant flows into the outdoor heat exchanger 6 forcibly blown by the outdoor fan 7, where it evaporates by exchanging heat with the surrounding air, and flows out as a gas-rich gas-liquid two-phase refrigerant or a saturated gas refrigerant. To do. The low-pressure gas refrigerant that has flowed out flows into the internal heat exchanger 9 via the four-way valve 2, exchanges heat with the liquid refrigerant flowing through the receiver 5, becomes superheated gas, and returns to the compressor 1. Since the refrigerant operation of the outdoor unit refrigerant circuit in the hot water heating operation is the same as that in the hot water supply operation, the description thereof is omitted. The operation of the water in the load side system of the hot water supply operation and hot water heating operation is the same as the description of FIG.

  In the case of the cold water cooling operation, in the refrigerant circuit of the outdoor unit, the high-pressure high-temperature gas refrigerant discharged from the compressor 1 flows into the outdoor heat exchanger 6 forcibly ventilated by the outdoor fan 7 through the four-way valve 2. It exchanges heat with ambient air, condenses, and flows out as a high-pressure liquid refrigerant. The high-pressure liquid refrigerant that has flowed out is decompressed by the decompression device 4b and becomes a medium-pressure liquid-rich gas-liquid two-phase refrigerant and flows into the receiver 5, and the low-pressure gas that circulates in the pipe by the internal heat exchanger 9 in the receiver 5. Heat exchange with the refrigerant condenses, flows out as a saturated liquid refrigerant, flows into the decompression device 4a, where it is decompressed and becomes a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant flows into the water-refrigerant heat exchanger 3, where the load-side unit supplies cold heat to evaporate, and flows out as a gas-rich gas-liquid two-phase refrigerant or a saturated gas refrigerant. The low-pressure gas refrigerant that has flowed out flows into the internal heat exchanger 9 via the four-way valve 2, where it exchanges heat with the liquid refrigerant in the receiver to become superheated gas and returns to the compressor 1. Since the operation of the water in the load side system is the same as the description of FIG.

  The effect of providing the internal heat exchanger 9 in the receiver 5 is that the compressor suction refrigerant is in a superheated gas state to ensure compressor reliability, and the refrigerant state at the outlet of the evaporator is a gas-rich gas-liquid two-phase refrigerant or saturated gas. The state is that the heat transfer performance of the heat exchanger can be improved. It is well known that the heat transfer performance in the pipe is better when the gas-liquid two-phase flow is better than the liquid or gas single-phase flow rate. If the outlet refrigerant state of the evaporator is superheated gas, the gas single-phase refrigerant will circulate in the vicinity of the outlet. The heat transfer coefficient in the pipe is lowered, and the heat exchange performance of the heat exchanger is lowered. On the other hand, if the refrigerant sucked into the compressor is in a gas-liquid two-phase state, a compressor failure due to liquid compression may occur. If the internal heat exchanger 9 is introduced, these problems can be avoided.

  The hot water supply operation is a transient operation in which the hot water temperature constantly changes, and the hot water supply and cold / hot water air conditioners have fewer refrigerant retention points than the air-cooled air conditioner, so if the refrigerant distribution in the circuit becomes unstable, the compressor The effect is particularly great in hot water supply and cold / hot water air conditioners because of easy liquid back. The same effect can be obtained when the internal heat exchanger 9 is applied to the refrigerant circuit shown in FIGS.

Embodiment 5 FIG.
Another device configuration will be described.
FIG. 8 is a refrigerant circuit diagram of the hot water supply and cold / hot water air conditioner according to Embodiment 5 of the present invention.
As shown in FIG. 8, the refrigerant circuit includes a compressor 1, a four-way valve 2, a water / refrigerant heat exchanger 3, decompressors 4 a to 4 c, a receiver 5, an air-cooled heat exchanger 6, an outdoor fan 7, and an outdoor fan motor 8. , The internal heat exchanger 9 and the internal heat exchanger 11, and the water circuit is composed of a water pump 21, a three-way valve 22, a hot water supply tank 23, a tank internal heat exchanger 24, and a cold / hot water air conditioning heat exchanger 25. It is configured.
FIG. 8 shows a configuration in which a receiver internal heat exchanger 9 is added inside the receiver 5 in the refrigerant circuit of FIG. 4.

  The operation of the load side system is the same as in FIG. The refrigerant operation of the outdoor unit refrigerant circuit when performing hot water supply and hot water heating operation will be described. The high-pressure and high-temperature gas refrigerant discharged from the compressor 1 flows into the water-refrigerant heat exchanger 3 through the four-way valve 2, where the heat is supplied to the load-side unit to condense, and flows out as high-pressure liquid refrigerant. The high-pressure liquid refrigerant that has flowed out is reduced in pressure by the decompression device 4a and becomes a medium-pressure liquid-rich gas-liquid two-phase refrigerant and flows into the receiver 5, and the low-pressure gas that circulates in the pipe by the internal heat exchanger 9 in the receiver 5. Heat is exchanged with the refrigerant to condense, flow out as a saturated liquid refrigerant, and flow into the internal heat exchanger 2_11. Here, the medium-pressure saturated liquid refrigerant is supercooled and flows out, and is decompressed by the decompression device 4b to become a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant flows into the outdoor heat exchanger 6 forcibly blown by the outdoor fan 7, where it evaporates by exchanging heat with the surrounding air, and flows out as a gas-rich gas-liquid two-phase refrigerant or a saturated gas refrigerant. To do. The low-pressure gas refrigerant that has flowed out flows into the internal heat exchanger 9 via the four-way valve 2, where it exchanges heat with the liquid refrigerant in the receiver to become superheated gas and returns to the compressor 1. A part of the medium-pressure supercooled refrigerant that has flowed out of the internal heat exchanger 2_11 flows into the decompression device 4c, where it is decompressed and becomes a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant flows into the internal heat exchanger 2_11, where it exchanges heat with the medium-pressure liquid refrigerant and evaporates to return to the front of the internal heat exchanger 9 as a gas-rich gas-liquid two-phase refrigerant.

  A conventional refrigeration air conditioner is also provided with a gas-liquid separator at the intermediate pressure part between the condenser and the evaporator, and the gas refrigerant separated by the gas-liquid separator is injected into the intermediate pressure part of the compressor for heating. Some are designed to improve their abilities. However, the conventional refrigeration and air-conditioning apparatus has the following problems. First, the receiver 5 conventionally has a gas-liquid separation function. When performing injection with a gas-liquid separator, the amount of liquid in the gas-liquid separator changes depending on the amount of injection, and the liquid refrigerant amount distribution in the refrigeration cycle fluctuates accordingly. there were. That is, when the injected gas refrigerant flow rate and the gas refrigerant flow rate of the two-phase refrigerant flowing into the gas-liquid separator are balanced, only the liquid refrigerant flows out to the evaporator side, and the gas-liquid separation is performed. The amount of liquid refrigerant in the vessel is stable, but when the flow rate of injected refrigerant decreases and becomes less than the flow rate of gas refrigerant flowing into the gas-liquid separator, the gas refrigerant also flows out to the evaporator side, and the bottom of the gas-liquid separator Since the gas flows out of the gas, the liquid in the gas-liquid separator is almost discharged. Conversely, when the flow rate of the injected refrigerant increases, there is not enough gas refrigerant, so liquid refrigerant is also injected into the gas refrigerant and liquid flows out from the top of the gas-liquid separator. The liquid is almost full.

  The injection flow rate is likely to fluctuate depending on the high and low pressures of the refrigeration cycle, the pressure of the gas-liquid separator, the operating capacity of the compressor, etc., so the injection flow rate rarely matches the gas refrigerant flow rate flowing into the gas-liquid separator. The amount of liquid refrigerant in the gas-liquid separator is almost zero or full, and the amount of refrigerant in the gas-liquid separator is likely to vary depending on the operating conditions. As a result, the refrigerant amount distribution in the refrigeration cycle fluctuates and operation instability is likely to occur.

In the fifth embodiment, the internal heat exchanger 11 is provided in place of the gas-liquid separator, so that a reduction in the discharge temperature of the compressor is suppressed even when the flow rate of the gas-injected refrigerant is large, and the indoor heat exchanger By exhibiting sufficient heat exchange performance, it is possible to ensure sufficient heating capacity even under conditions where the heating capacity tends to decrease under low outside air temperature conditions, and when supplying a refrigerant that performs gas injection, Regardless of the gas-liquid separator, the bypassed refrigerant is gasified and supplied by the second internal heat exchange, thereby avoiding fluctuations in the liquid volume due to the use of the gas-liquid separator and realizing more stable device operation. In addition, it is possible to further increase the gas injection amount while suppressing a decrease in the discharge temperature of the compressor, further improving the heating capacity and improving the efficiency during the defrosting operation. An effect that can be. As a result, the heating capacity under low outdoor temperature conditions can be supplied more stably than before.
By using a gas injection circuit with the internal heat exchanger 11, the following effects can be obtained. First, by performing gas injection, the refrigerant flow rate discharged from the compressor 1 increases, and the refrigerant flow rate Gdis discharged from the compressor 1, the refrigerant flow rate Gsuc sucked in the compressor 3, and the injected refrigerant flow rate Ginj The relational expression of
Gdis = Gsuc + Ginj
Therefore, since the flow rate of the refrigerant flowing through the heat exchanger serving as a condenser increases, the heating capacity increases in the heating operation.

  When performing gas injection, an efficiency improvement effect is obtained. The refrigerant flowing into the heat exchanger serving as an evaporator is generally a gas-liquid two-phase refrigerant, but among these, the gas refrigerant does not contribute to the cooling capacity. From the viewpoint of the compressor, this low-pressure gas refrigerant also works to increase the pressure together with the gas refrigerant evaporated in the evaporator. When gas injection is performed, some of the gas refrigerant flowing into the evaporator is extracted at an intermediate pressure, injected, boosted from the intermediate pressure to a high pressure, and compressed. Therefore, with respect to the flow rate of the injected gas refrigerant, the compression work for increasing the pressure from the low pressure to the intermediate pressure becomes unnecessary, and the efficiency is improved accordingly. This effect can be obtained in any operation of air conditioning.

  When the heat source 12 is added to the injection circuit as shown in FIG. 11, it is possible to further increase the amount of the injection refrigerant while suppressing a decrease in the compressor discharge temperature, thereby further reducing the defrosting time. Further, by using it at the time of returning to hot water supply and hot water heating operation, further improvement of the start of hot water supply and hot water heating operation can be realized.

Embodiment 6 FIG.
Another device configuration will be described.
FIG. 9 is a refrigerant circuit diagram of the hot water supply and cold / hot water air conditioner according to Embodiment 6 of the present invention.
As shown in FIG. 9, the refrigerant circuit includes a compressor 1, a four-way valve 2, a water / refrigerant heat exchanger 3, decompression devices 4 a and 4 b, a receiver 5, an outdoor heat exchanger 6, an outdoor fan 7, and an outdoor fan motor 8. The water circuit includes a water pump 21, a three-way valve 22, a hot water supply tank 23, a tank internal heat exchanger 24, and a cold / hot water / air conditioning heat exchanger 25.

  The operation of the refrigerant and the operation of water are the same as those described with reference to FIG.

  Although this system can supply heat to a plurality of load-side systems at one time, there are other advantages as follows. Of the water-refrigerant heat exchanger 3, the load-side unit that exchanges heat with the refrigerant upstream receives heat at a high temperature, and the load-side unit that exchanges heat with the refrigerant downstream receives heat at a low temperature. If the upstream side is mainly used for hot water supply and the downstream side is mainly used for hot water heating, hot water supply and hot water heating can be easily and simultaneously operated. FIG. 10 shows a refrigerant circuit that can supply cold / hot heat to the system in parallel.

It is a hot-water supply and cold / hot water air conditioning apparatus figure by Embodiment 1 of this invention. It is another figure of the hot water supply and cold / hot water air conditioning apparatus by Embodiment 1 of this invention. It is another figure of the hot water supply and cold / hot water air conditioning apparatus by Embodiment 1 of this invention. It is another figure of the hot water supply and cold / hot water air conditioning apparatus by Embodiment 1 of this invention. It is another figure of the hot water supply and cold / hot water air conditioning apparatus by Embodiment 1 of this invention. It is another figure of the hot water supply and cold / hot water air conditioning apparatus by Embodiment 1 of this invention. It is another figure of the hot water supply and cold / hot water air conditioning apparatus by Embodiment 1 of this invention. It is another figure of the hot water supply and cold / hot water air conditioning apparatus by Embodiment 1 of this invention. It is another figure of the hot water supply and cold / hot water air conditioning apparatus by Embodiment 1 of this invention. It is another figure of the hot water supply and cold / hot water air conditioning apparatus by Embodiment 1 of this invention. It is another figure of the hot water supply and cold / hot water air conditioning apparatus by Embodiment 1 of this invention. It is an example of the temperature state of the water and the refrigerant | coolant which flow through the water refrigerant | coolant heat exchanger of Embodiment 1 of this invention. It is a figure which shows the structural example of the prior art of a hot water supply and a cold / hot water air conditioning apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Compressor, 2 Four way valve, 3 Water refrigerant | coolant heat exchanger, 4a-4c Pressure reducing device, 5 Receiver, 6 Air-cooling type heat exchanger, 7 Outdoor fan, 8 Outdoor fan motor, 9 Receiver internal heat exchanger, 10 Accumulator , 11 Internal heat exchanger 2, 12 Heat source, 21 Water pump, 22 Three-way valve, 23 Hot water tank, 24 Tank internal heat exchanger, 25 Water refrigerant heat exchanger 2, 26 Heat exchanger for underground heat exhaust, 27 Water pump, 28 Water / water heat exchanger, 31 Outdoor unit ambient dry bulb temperature detection means, 32 Water refrigerant heat exchanger inlet water temperature detection means, 33 Air-cooled heat exchanger liquid pipe side refrigerant temperature detection means, 34 Water refrigerant Liquid pipe side refrigerant temperature detection means of heat exchanger, 35 compressor discharge temperature detection means, 36 compressor discharge pressure detection means, 41 load side control / communication means, 42 outdoor unit control / communication means.

Claims (26)

The refrigerant, which is provided in the outdoor unit, sequentially circulates through a compressor with variable rotation speed, a four-way valve, a first heat exchanger that exchanges heat with water, and a second heat exchanger that exchanges heat with air and refrigerant. A refrigerant circuit;
A water circuit comprising a water conveying means and a hot water tank , wherein water is circulated in turn through the water conveying means, the first heat exchanger , and the hot water tank;
Two decompression devices provided in series with a pipe communicating the first heat exchanger and the second heat exchanger;
A receiver provided between the two pressure reducing devices, and storing the refrigerant;
During the defrost operation in which the refrigerant circulates in the direction opposite to the direction of the circulation , the opening of the two pressure reducing devices is fully opened, and immediately before the end of the defrost operation, the control means opens the opening of the upstream pressure reducing device. With the fully open, the opening of the decompression device on the downstream side is controlled to be small,
At the time of hot water supply and hot water heating operation, the pressure reducing device on the upstream side is controlled so that the degree of subcooling at the outlet of the heat exchanger serving as the condenser of the first and second heat exchangers becomes a predetermined target value. A hot water supply and cold / hot water air conditioner, comprising: a control unit that controls an opening degree of the downstream pressure reducing device based on a compressor discharge temperature or a compressor discharge superheat degree.   In the cold water cooling operation, the control means controls the downstream pressure reducing device so that the degree of subcooling at the outlet of the heat exchanger serving as an evaporator of the first and second heat exchangers becomes a predetermined target value. The hot water supply and cold / hot water air conditioner according to claim 1, wherein control is performed.   The hot water supply / cold / hot water air conditioner according to claim 1, wherein the control unit controls a decompression device on the downstream side so that a discharge temperature of the compressor becomes a predetermined target value.   The hot water supply / cold hot / cold water / air conditioning apparatus according to claim 1, wherein the control unit controls a decompression device on the downstream side so that a discharge superheat degree of the compressor becomes a predetermined target value.   The hot water supply and cold / hot water air conditioner according to claim 1, wherein the water circuit includes a heat exchanger for cooling and heating instead of the hot water supply tank. The water circuit further includes a bypass having a heat exchanger for cooling and heating,
A switching valve provided at the bypass branch point is provided,
The hot water supply according to any one of claims 1 to 4, wherein the control means controls the switching valve so that water passes through either the heat exchanger for cooling or heating or the hot water supply tank. Cold and hot water air conditioner. An outdoor unit is provided with a water transfer means and an underground heat exhaust heat exchanger, and water sequentially circulates through the water transfer means, the underground heat exhaust heat exchanger, and the second heat exchanger . The hot water supply and cold / hot water air conditioner according to claim 1, further comprising a water circuit. Provided between the refrigerant circuit and the water circuit;
A third heat exchanger for exchanging heat with the water circuit, and water transport means,
An intermediate circuit in which water circulates sequentially through the first heat exchanger, the third heat exchanger, and the water conveying means;
In the said water circuit, water passes the said 3rd heat exchanger instead of the said 1st heat exchanger, The hot water supply and cold / hot water air conditioning apparatus in any one of Claims 1-6 characterized by the above-mentioned. .   The receiver is configured to exchange heat between the refrigerant passing through the interior and the refrigerant passing between the compressor and the heat exchanger serving as an evaporator in the first and second heat exchangers. The hot water supply and cold / hot water air conditioner in any one of Claims 1-8 characterized by the above-mentioned. An injection circuit that is branched from a pipe between the receiver of the refrigerant circuit and the decompression device on the second heat exchanger side, and injects into the compressor;
A decompression device for injection provided in the injection circuit;
An internal heat exchanger for injection that is provided in the injection circuit and exchanges heat between the refrigerant decompressed by the decompression device for injection and the refrigerant in the refrigerant circuit that has passed through the receiver;
The hot water supply and cold / hot water air conditioner of Claim 8 characterized by the above-mentioned.   The hot water supply and cold / hot water air conditioner according to claim 1, wherein the first heat exchanger is a plate heat exchanger. The outdoor unit includes a compressor discharge temperature detecting means for detecting a discharge temperature of the compressor, a compressor discharge pressure detecting means for detecting a discharge pressure of the compressor, and a liquid pipe of the first heat exchanger. Water refrigerant heat exchanger liquid pipe connection port temperature detection means for detecting the temperature of the connection port, and air-cooled heat exchanger liquid pipe connection port temperature detection means for detecting the temperature of the liquid pipe connection port of the second heat exchanger And an outdoor unit ambient dry bulb temperature detecting means for detecting a dry bulb temperature around the outdoor unit, and a water refrigerant heat exchanger water inlet temperature detecting unit for detecting the temperature of the water inlet of the first heat exchanger. Provided,
The control means is an outdoor unit control / communication means provided in the outdoor unit,
On the water circuit side, load control and communication means are provided,
The load control / communication means transmits the required capacity from the water circuit side to the outdoor unit control / communication means,
The outdoor unit control / communication means is based on the required capacity from the load control / communication means, the output of the outdoor unit ambient dry bulb temperature detection means, and the output of the water refrigerant heat exchanger water inlet temperature detection means. The number of rotations of the compressor motor is determined, the number of rotations of the fan motor of the outdoor unit is determined based on the output of the outdoor unit ambient dry bulb temperature detection means, the output of the compressor discharge pressure detection means and the From the output of the water refrigerant heat exchanger liquid pipe connection port temperature detection means, the degree of subcooling at the outlet of the heat exchanger that becomes the condenser in the first and second heat exchangers is calculated, and the value is a predetermined target. The opening of the decompression device on the upstream side is determined so as to be a value, the opening of the decompression device on the downstream side is determined so that the output of the compressor discharge temperature detection means becomes a predetermined target value, and sequentially during operation It performs, The hot water supply in any one of Claims 1-9 characterized by the above-mentioned. Hot and cold water air-conditioning apparatus.   The outdoor unit control / communication means includes a condenser in the first and second heat exchangers based on the output of the compressor discharge pressure detecting means and the output of the water refrigerant heat exchanger liquid pipe connection port temperature detecting means. Instead of calculating the degree of subcooling at the outlet of the heat exchanger, the first and second heats are obtained from the output of the compressor discharge pressure detecting means and the output of the air-cooled heat exchanger liquid pipe connection port temperature detecting means. The hot water supply and cold / hot water air conditioner according to claim 12, wherein the degree of supercooling at the outlet of the heat exchanger that serves as a condenser in the exchanger is calculated.   The outdoor unit control / communication means outputs the output of the compressor discharge pressure detection means instead of determining the opening of the downstream pressure reducing device so that the output of the compressor discharge temperature detection means becomes a predetermined target value. And the output of the compressor discharge temperature detection means, the discharge superheat degree of the compressor is calculated, and the opening of the decompression device on the downstream side is determined so that the value becomes a predetermined target value. The hot water supply and cold / hot water air conditioner of Claim 12.   When the hot water supply or hot water heating is performed at a low outside air temperature, the control means fully opens the opening of the decompression device communicating with the second heat exchanger on the upstream side during the defrost operation, and the first on the downstream side. The pressure reducing device communicating with the first heat exchanger is set to a predetermined opening smaller than the full opening, and when the defrosting is finished and the hot water supply and hot water heating are started up, the pressure reducing device communicates with the first heat exchanger on the upstream side for a predetermined time. The hot water supply / cooling temperature according to any one of claims 1 to 11, wherein the opening degree of the apparatus is set to an opening degree smaller than the opening degree of the decompression device communicating with the second heat exchanger on the downstream side. Water air conditioner. A plurality of first heat exchangers provided in series in the refrigerant circuit;
A plurality of water circuits provided for each of the first heat exchangers, each having a heat exchanger for cooling and heating, a hot water supply tank, and a switching valve;
The control means mainly uses a water circuit connected via the first heat exchanger on the upstream side for hot water supply, and mainly cools and cools the water circuit connected via the first heat exchanger on the downstream side. The hot water supply / cold hot / cold water / air conditioning apparatus according to claim 1, wherein the switching valve is controlled so as to be used for water / air conditioning.   The hot water supply and cold / hot water air conditioner according to claim 10, wherein the injection circuit includes a heat source for heating the refrigerant.   The hot water supply and cold / hot water air conditioner according to claim 1, wherein the compressor is a rotary type.   The hot water supply or cold / hot water according to any one of claims 1 to 10, wherein the compressor is of a scroll type provided with a valve that discharges the overcompressed gas to the outside of the compression chamber when the compression chamber is overcompressed. Air conditioner.   The hot water supply and cold / hot water air conditioner according to claim 1, wherein the compressor is of a scroll type provided with a suction unload mechanism.   12. The refrigerant circuit of the outdoor unit, wherein the refrigerant weight when the 0 ° C. saturated liquid refrigerant occupies 1/2 of the outdoor heat exchanger volume is set as a necessary minimum charged refrigerant amount. Hot water supply and cold / hot water air conditioner as described in Crab.   The hot water supply and cold / hot water air conditioner according to claim 1, wherein a critical point temperature of the refrigerant used is at least 5 ° C. higher than an outlet water temperature of the water refrigerant heat exchanger.   In the case of hot water supply or hot water heating operation, the control means is configured such that when the water refrigerant heat exchanger inlet water temperature in the load side unit is equal to or lower than a predetermined temperature, the degree of subcooling of the outlet refrigerant of the water refrigerant heat exchanger is equal to or higher than a predetermined temperature. The hot water supply / cold hot / cold water / air conditioning apparatus according to claim 1, wherein a pressure reducing device communicating with the first heat exchanger is controlled to be large.   In the hot water supply or hot water heating operation, the control means is configured such that when the outdoor unit ambient dry bulb temperature is equal to or lower than a predetermined temperature, the degree of supercooling of the outlet refrigerant of the water refrigerant heat exchanger is higher than that at a predetermined temperature or higher. The hot water supply and cold / hot water air conditioner according to any one of claims 1 to 11, wherein a decompression device communicating with the first water refrigerant heat exchanger is controlled.   The said control means always makes the dryness of the exit refrigerant | coolant of a water-refrigerant heat exchanger less than 1 irrespective of the amount of refrigerant | coolants enclosed, when carrying out cold water cooling operation, The one of Claims 1-11 characterized by the above-mentioned. Hot water supply and cold / hot water air conditioner.   The hot water supply or cold / hot water air according to any one of claims 1 to 11, wherein the water conveying means is configured such that a water flow velocity in the water circuit or the intermediate circuit is suppressed to 1.5 m / sec or less. Harmony device.

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