JP2006003079A - Refrigerating air conditioner and control method for refrigerating air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem wherein it is difficult to obtain a high-safety and high-reliability refrigerating air conditioner, by using a combustible refrigerant imparting only a very small bad influence to the global environment as a refrigerant of a refrigeration cycle. <P>SOLUTION: This refrigerating air conditioner has: a primary side cycle sequentially connecting a compressor, a heat source side heat exchanger, a throttle device and an intermediate heat exchanger to circulate the combustible refrigerant; and a secondary side cycle sequentially connecting a pump, a use side heat exchanger and the intermediate heat exchanger to circulate an incombustible refrigerant. Electric input of the pump and the compressor is detected with a preset setting value as a rotation speed of the pump, the rotation speed of the pump is changed, and electric input of the pump and the compressor is detected by operation of the changed rotation speed. By the change in the rotation speed and the detection of the electric input in the rotation speed, the pump is operated at the rotation speed when a total of the electric input of the pump and the compressor becomes small. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a refrigeration air conditioner such as a home air conditioner and a control method for the refrigeration air conditioner.

  Currently, chlorofluorocarbon refrigerants are used as refrigerants in refrigerating and air-conditioning apparatuses such as refrigerators and air conditioners. Among CFC-based refrigerants, CFC-based refrigerants and HCFC-based refrigerants are being transferred to HFC-based fluorocarbon refrigerants in order to destroy the ozone layer. However, this HFC-based refrigerant is a substance that promotes global warming, and it has been studied to use a natural refrigerant such as a hydrocarbon-based refrigerant or ammonia that does not deteriorate the global environment as a refrigerant for a refrigeration air conditioner. However, this hydrocarbon refrigerant, ammonia, and HFC refrigerant, such as R32, which has relatively little influence on global warming, are flammable in nature, so why can't they be used in conventional refrigeration and air conditioning equipment as they are? There wasn't.

  A conventional refrigeration air conditioner using a flammable refrigerant has a refrigeration cycle in which a compressor, a condenser, an expansion valve as an expansion device, and an evaporator 5 are sequentially connected by a pipe to form a refrigeration cycle. Hydrocarbon refrigerants such as (propane) and R600a (isobutane) are used to constitute the primary side cycle. The compressor 1 is filled with lubricating oil, and this lubricating oil circulates in the refrigeration cycle together with the refrigerant.

Further, the secondary cycle is configured by connecting a brine circulation pump, an indoor heat exchanger, and a brine heat exchanger by piping. In the secondary cycle, brine such as a calcium chloride aqueous solution or a sodium chloride aqueous solution is used as a heat transfer medium. (For example, see Patent Document 1)
JP-A-10-35266

  In the conventional refrigerating and air-conditioning apparatus as described above, a hydrocarbon-based refrigerant that has a very small influence on global warming is used as a refrigerant for the refrigerating and air-conditioning apparatus in order to suppress global warming. However, in order to suppress global warming, it is important to suppress not only global warming of the refrigerant itself but also global warming due to the use of electric power of the refrigeration air conditioner. That is, improving the energy efficiency of the refrigeration air conditioner is also an important issue, but the conventional refrigeration air conditioner has not been configured in consideration of the energy efficiency. In particular, the number of rotations of the brine circulation pump 11 is constant, and the operation is performed at the maximum setting that can obtain the necessary brine flow rate even when the load increases, resulting in a problem that the energy input decreases and the energy efficiency decreases. There was a point.

  In addition, when a hydrocarbon system is used as the refrigerant in the primary side refrigeration cycle of a conventional refrigeration air conditioner, the hydrocarbon system refrigerant has high mutual solubility with the lubricating oil, and a large amount of refrigerant dissolves in the lubricating oil in the compressor. Since the viscosity decreases, the amount of oil discharged from the compressor increases, the pressure loss in the primary refrigeration cycle increases, the heat transfer performance of the heat exchanger decreases, and the energy of the primary refrigeration cycle decreases. In some cases, the efficiency decreased.

  In order to improve safety when using flammable refrigerants, the amount of refrigerant charged in the refrigeration air conditioner can be reduced, refrigerant leakage from the device can be suppressed, or in the unlikely event of refrigerant leakage It is required to find and repair the leaked part at an early stage.

The present invention has been made to solve the conventional problems as described above, and has a primary side refrigeration cycle and a secondary side heat transport cycle. The object is to obtain a method for controlling the apparatus.
It is another object of the present invention to provide a refrigeration air conditioner capable of preventing a decrease in energy efficiency even when a refrigerant having high compatibility with the lubricating oil in the compressor is used as the refrigerant in the refrigeration cycle.
Moreover, it aims at obtaining the refrigerating air-conditioning apparatus which can improve energy efficiency and safety | security when a combustible refrigerant | coolant is used as a refrigerant | coolant of a refrigerating cycle.

  The control method of the refrigerating and air-conditioning apparatus according to the present invention includes a primary cycle in which a compressor, a heat source side heat exchanger, an expansion device, and an intermediate heat exchanger are sequentially connected, and a primary side heat transfer medium is circulated, a pump, and a use side A heat exchanger, a secondary cycle for sequentially connecting the intermediate heat exchanger and circulating the secondary heat transfer medium, and a primary heat transfer medium and a secondary heat transfer medium in the intermediate heat exchanger, In the refrigeration air conditioner configured to exchange heat between the secondary side heat transfer medium and the use side heat medium in the use side heat exchanger, the primary side heat transfer medium is a flammable refrigerant, The secondary heat transfer medium is a non-combustible medium, and the electric input of the compressor and the pump is detected using the preset set value as the rotation speed of the pump, and the rotation speed of the pump is changed and changed. The compressor and the pump are operated at the rotational speed. The electric input is detected, and the pump is operated at the rotation speed when the total of the electric inputs of the compressor and the pump is reduced by the change of the rotation speed and the detection of the electric input at the rotation speed. is there.

As described above, according to the control method of the refrigeration air conditioner of the present invention, the primary side cycle in which the compressor, the heat source side heat exchanger, the expansion device, and the intermediate heat exchanger are sequentially connected to distribute the primary side heat transfer medium. And a secondary side cycle in which a pump, a use side heat exchanger, and the intermediate heat exchanger are sequentially connected, and a secondary heat transfer medium is circulated, and the primary heat transfer medium and the secondary heat transfer medium are connected with the intermediate heat exchanger. In the refrigeration air conditioner configured to exchange heat with the secondary heat transfer medium and to exchange heat between the secondary heat transfer medium and the use side heat medium in the use side heat exchanger, the primary side heat transfer medium is It is a flammable refrigerant, the secondary heat transfer medium is a non-flammable medium, detects the electrical input of the compressor and the pump with a preset set value as the rotation speed of the pump, and the rotation speed of the pump Change the compressor in operation at the changed speed The electric input of the pump is detected, and the pump is rotated at the rotation speed when the total of the electric inputs of the compressor and the pump is reduced by changing the rotation speed and detecting the electric input at the rotation speed. A control method for a refrigerating and air-conditioning apparatus, comprising:
As a result, the total electric input can be controlled to be small, and the energy efficiency can be improved.

Embodiment 1 FIG.
Hereinafter, a refrigerating and air-conditioning apparatus according to Embodiment 1 of the present invention will be described. FIG. 1 is a refrigerant circuit diagram showing a domestic air conditioner that is a refrigerating and air-conditioning apparatus according to the first embodiment. In the figure, 1 is a compressor, 2 is a flow path switching means for switching the flow of refrigerant in cooling operation and heating operation, for example, a four-way valve, 3 is an outdoor heat exchanger which is a heat source side heat exchanger, and 4 is an expansion device. The electric expansion valve 5 is a refrigerant flow path in the intermediate heat exchanger 10, and these are sequentially connected by piping, and constitute a refrigeration cycle that is a primary side cycle by circulating a primary side heat transfer medium. 6 is an inverter for driving a compressor, and 7 is an outdoor fan. As a heat transfer medium (hereinafter referred to as a refrigerant) of this primary cycle, for example, a hydrocarbon system such as R290 (propane) or R600a (isobutane) which is a flammable refrigerant has a very small influence on global warming. A refrigerant is used. Moreover, in the compressor 1, for example, mineral oil is enclosed as lubricating oil for lubrication of the compressor sliding portion.

  Further, as the secondary heat transfer medium (hereinafter referred to as brine), for example, brine is used as the nonflammable medium such as brine, water, carbon dioxide, and the configuration of the secondary cycle is as follows. 11 is a pump, for example, a brine circulation pump, 12 is an indoor heat exchanger that is a use side heat exchanger, 13 is a brine flow path in the intermediate heat exchanger 10, and 14 is a secondary side heat medium storage tank that is a brine tank. These are connected by a brine pipe and constitute a secondary side heat transport cycle which is a secondary side cycle to circulate brine which is a heat transfer medium for heat transport. Reference numeral 15 denotes a variable flow rate mechanism capable of changing the flow rate of the secondary heat transfer medium in the secondary cycle, for example, a pump drive inverter that controls the circulating flow rate of brine by changing the rotational speed of the pump 11. Is an indoor blower. As this brine, for example, calcium chloride aqueous solution or sodium chloride aqueous solution is used. For example, a plate heat exchanger is used as the intermediate heat exchanger 10, and heat exchange between the refrigerant and the brine is performed via the refrigerant flow path 5 and the brine flow path 13.

  The outdoor unit 51 is configured by piping including the brine tank 14 and the brine circulation pump 11 of the entire primary cycle and the secondary cycle, and is installed outdoors. The use side heat exchanger 12 and the use side blower 16 constitute an indoor unit 52 and are installed in a room where people live. Reference numeral 17 denotes a control device arranged in the outdoor unit 51, which is composed of, for example, a microcomputer and performs operations of compressor rotation speed control and pump rotation speed control. That is, according to the load on the use side heat exchanger 12 and the electric input of each device, the rotational speed of the inverter 15 for driving the pump and the rotational speed of the inverter 6 for driving the compressor are shown in FIG. The signal which controls each is transmitted.

  Next, the heating operation and cooling operation of the refrigerating and air-conditioning apparatus according to Embodiment 1 will be described. In FIG. 1, the flow of the refrigerant and brine during the heating operation is indicated by solid arrows, and the flow of the refrigerant and brine during the cooling operation is indicated by broken arrows. First, the operation during heating operation will be described. In the primary side cycle, the high-temperature and high-pressure refrigerant vapor exiting the compressor 1 passes through the four-way valve 2 and flows into the intermediate heat exchanger 10. The refrigerant that has flowed into the refrigerant flow path 5 in the intermediate heat exchanger 10 is cooled, condensed, and liquefied by the brine flowing in the brine flow path 13. The high-pressure liquid refrigerant that has exited the intermediate heat exchanger 10 flows into the electric expansion valve 4 and is depressurized, becomes a low-pressure gas-liquid two-phase refrigerant, and flows into the outdoor heat exchanger 3 that operates as an evaporator. This low-pressure gas-liquid two-phase refrigerant takes heat from the outside air in the outdoor heat exchanger 3 and evaporates to become low-pressure vapor refrigerant and flows out from the intermediate heat exchanger 10. This low-pressure vapor refrigerant passes through the four-way valve 2 and is sucked into the compressor 1 again.

  Moreover, in the secondary side cycle at the time of heating operation, the brine discharged by the brine circulation pump 11 flows into the indoor heat exchanger 12 and exchanges heat with room air to heat the room. The brine whose heat has been taken away by the room air and whose temperature has dropped flows into the intermediate heat exchanger 10. And while flowing in the brine flow path 13 in the intermediate heat exchanger 10, it is heated by the refrigerant flowing in the refrigerant flow path 5, and the brine temperature rises. The brine that has exited the intermediate heat exchanger 10 passes through the brine tank 14 and flows into the brine circulation pump 11 again.

  Next, operation during cooling operation will be described. In the primary side cycle, the high-temperature and high-pressure refrigerant vapor exiting the compressor 1 passes through the four-way valve 2 and flows into the outdoor heat exchanger 3, where heat is taken away by the outside air, and condensed and liquefied. The high-pressure liquid refrigerant exiting the outdoor heat exchanger 3 flows into the electric expansion valve 4 and is depressurized, and becomes a low-pressure gas-liquid two-phase refrigerant and flows into the intermediate heat exchanger 10. Then, while flowing through the refrigerant flow path 5 in the intermediate heat exchanger 10, it is heated by the brine flowing in the brine flow path 13, becomes low-pressure steam, and flows out from the intermediate heat exchanger 10. This low-pressure vapor refrigerant passes through the four-way valve 2 and is sucked into the compressor 1 again.

  In the secondary side cycle during the cooling operation, the brine discharged by the brine circulation pump 11 flows into the indoor heat exchanger 12, exchanges heat with room air, and cools the room. The brine heated by the room air and having a raised temperature flows into the intermediate heat exchanger 10. And while flowing in the brine flow path 13 in the intermediate heat exchanger 10, it is cooled by the refrigerant flowing in the refrigerant flow path 5, and the brine temperature decreases. The brine that has exited the intermediate heat exchanger 10 passes through the brine tank 14 and flows into the circulation pump 11 again.

  Next, a control method for a home air conditioner, for example, as the refrigeration air conditioner according to the first embodiment will be described. Since the basic control method during the heating operation and the cooling operation is the same, here, for example, a control method during the heating operation will be described. An inverter 6 is connected to the compressor 1, and the control device 17 can detect the heating load on the indoor side based on the difference between the indoor set temperature and the indoor temperature, etc., and can exert the heating capacity according to the indoor heating load. The rotation speed of the compressor 1 is determined by the compressor rotation speed control. And the control signal is transmitted to the inverter 6 from the control apparatus 17, and it is controlled by the inverter 6 so that it may become the rotation speed. The opening degree of the electric expansion valve 4 is controlled so that, for example, the refrigerant subcooling degree at the outlet of the intermediate heat exchanger 10 is about 5 ° C. even if the rotational speed of the compressor 1 changes. . The detection of the outlet supercooling degree of the intermediate heat exchanger 10 is performed by detecting the refrigerant temperature and pressure at the outlet of the intermediate heat exchanger 10, for example.

  The control device 17 receives the electrical input detected by each device, and determines the rotation speed of the brine circulation pump 11 so that the total electrical input of the home air conditioner is minimized. Then, a control signal is transmitted from the control device 17 to the pump drive inverter 15. The inverter 15 controls the brine circulation pump 11 so as to have the rotation speed commanded by the control signal. The total electric input of the air conditioner is obtained as the sum of the electric input of the compressor 1, the electric input of the outdoor fan 7, the electric input of the indoor fan 16, the electric input of the brine circulation pump 11, and the like.

  FIG. 2 is a graph showing changes in compressor input, outdoor fan input, indoor fan input, brine circulation pump input, and all inputs that are the sum of these when the brine flow rate is changed during heating operation. When the brine flow rate is increased, the heat transfer characteristics in the intermediate heat exchanger 10 are improved, and the condensation pressure of the primary side cycle is lowered, so that the compressor input is lowered. On the other hand, the brine circulation pump input increases with increasing brine flow rate. The outdoor blower and the indoor blower input are constant values regardless of the brine flow rate. For this reason, all inputs, which are the sum of the compressor input, the brine circulation pump input, the outdoor, and the indoor blower input, have a minimum value with respect to the brine flow rate change.

  Assuming that all the inputs when the brine circulation pump 11 having a constant rotational speed, which is a conventional device, is indicated by point A in FIG. 2, an air conditioner using the inverter-driven brine circulation pump 11 according to this embodiment. Then, since all the inputs are calculated and the brine flow rate is controlled so that all the inputs are minimized (point B in FIG. 2), it is possible to always operate with low power consumption.

  FIG. 3 is a flowchart showing the procedure of the pump speed control process of the control device 17. When the operation of the air conditioner is started, the rotation speed of the pump is initialized at step ST1. Here, the rotation speed of the pump is initially set to a larger value within the range of the operation region, and the electric input is controlled to the minimum while gradually decreasing the rotation speed. Various initial setting values for the rotational speed are conceivable. For example, the rotational speed of the pump 11 that has been empirically set in the operation region according to the rotational speed of the compressor 1 is stored in advance, and the compressor 1 rotates during operation. The maximum value of the operation region corresponding to the number is initially set as the rotation speed of the pump 11. Further, the difference between the indoor temperature at which the indoor heat exchanger 12 is installed and the indoor set temperature is set as the magnitude of the load, and the rotational speed of the pump 11 that is empirically set as the operation region according to the magnitude of the load is set in advance in the table. The maximum value of the operation region corresponding to the difference between the indoor temperature during operation and the indoor set temperature may be stored as an initial value as the rotation speed of the pump 11. Further, it may be initially set to the maximum value among the rotational speeds that have been empirically set in advance. Here, for example, the rotation speed when the rotation speed of the conventional pump is constant, for example, 60 Hz is initially set. When the pump 11 is set to this rotational speed and the air conditioner is operated, the brine flow rate and electric input indicated by point A in FIG. 2 are obtained.

  Next, in step ST2, the electrical input of each device is detected. In step ST3, the pump driving inverter 15 is operated to lower the rotational speed of the pump 11 by a predetermined value, for example, 5 Hz. And it is drive | operated for a fixed time, for example, about 3 minutes until the driving | operation is stabilized (step ST4). When the rotational speed of the pump 11 is decreased, the brine flow rate is decreased, the condensing pressure of the primary side cycle is increased, and the electric input of the compressor 1 is changed to be slightly increased. That is, the brine flow rate and the electric input move from the point A in FIG. Therefore, in step ST5, the electric input of each device is detected, and it is determined whether or not the total of all the electric inputs is lower than that detected in ST2. As a result, when the electric input is lowered, there is a possibility that the electric input is further minimized. Therefore, after storing the number of rotations of the pump 11 and the total electric input at that time, the process returns to step ST3 and the pump 11 is again performed. Decrease the number of revolutions by a predetermined value. Thus, the process of step ST3-step ST6 is repeated while all the electrical inputs are falling.

If the electric input is higher than the previous time in the determination of step ST6, the previous pump rotation speed state is the minimum electric input, and the state is restored (ST7).
If the indoor load changes greatly, for example, if the compressor speed changes significantly to 10 Hz or more, the pump speed control is performed again, and the pump speed is set in steps ST1 to ST7. Try again.

  Tables 1 and 2 show the electric input of the air conditioner using the brine circulation pump having a constant rotational speed, which is a conventional device, and the air conditioner using the inverter-driven brine circulation pump according to this embodiment. It is a comparison. Each electric input (%) of the compressor, the outdoor blower, the indoor blower, and the brine circulation pump during heating operation and cooling operation is shown, respectively. In addition, the numerical value in a table | surface is shown by the ratio with respect to all the inputs at the time of heating rating. In addition, this table shows the heating rated capacity, heating intermediate capacity, heating minimum capacity, heating low temperature capacity, cooling rated capacity, cooling intermediate capacity, and cooling minimum capacity used when calculating the annual energy consumption of the current room air conditioner. The evaluation result of each electric input is shown. The test when each capability value in this table was obtained is in accordance with the heating capability test and the cooling capability test in JIS standard (C9612-1994).

  In Table 1, since the brine flow rate is constant, the brine circulation pump input is also constant. In Table 2, since the brine flow rate is controlled so that the total electric input is minimized, the intermediate capacity is changed from the minimum capacity to the minimum capacity. The brine circulation pump input can be reduced, and the total electrical input can be reduced in this capacity band. As a result, assuming that the annual power consumption in Table 1 is 100, the annual power consumption in Table 2 in which the brine flow rate is controlled is 84, and the power consumption can be reduced by 16%.

  In the control shown in FIG. 3, the pump rotational speed is initially set to the maximum value in the operation region, and the rotational speed is gradually decreased to control the electric input to the minimum. Here, the pump rotational speed may be initially set to the minimum value of the operation region, and the rotational speed may be gradually increased to control the electric input to the minimum. In this case, control is performed from the state initially set to the left side of the point B of the curve indicating all inputs in the graph of FIG. 2 to the minimum point B while changing the state to the right.

  The set value in the initial setting may be set to an arbitrary number of rotations as well as the maximum value or the minimum value of the operation region. If the total electrical input increases when the rotational speed is increased or decreased, the rotational speed that minimizes the electrical input may be obtained by increasing or decreasing the rotational speed on the opposite side. However, if the initial setting is made with a value corresponding to the number of rotations of the compressor 1 or the load in the indoor heat exchanger 12, it can be smoothly controlled so that the total electric input is minimized, and the number of rotations at which the electric input is minimized. Time to get can be shortened. Further, the change when changing the number of revolutions may not always be constant. If the change width is made smaller as it approaches the minimum, the accuracy when controlling to the minimum electric input is improved.

In the first embodiment, in both the control for gradually decreasing the pump rotation speed and the control for gradually increasing the pump speed, the entire electric input of the air conditioner is detected and the brine is set so that the total electric input is minimized. The effect of improving the energy efficiency by controlling the flow rate is obtained.
At this time, as shown in Table 2, since the compressor 1 and the pump 11 largely depend on the reduction of the electric input without detecting all the electric inputs, at least the electric inputs of the compressor 1 and the pump 11 are detected. And the sum of the two may be minimized.

  Further, instead of minimizing these two electric inputs, the brine flow rate may be changed according to the size of the indoor load or the rotation speed of the compressor 1. For example, by controlling the brine flow rate so that the brine flow rate is reduced when the indoor air conditioning load is reduced by the pump drive inverter 16 that can change the brine flow rate, the electrical input can be reduced to some extent and the energy efficiency can be improved. Moreover, even if it controls so that a brine flow volume may be reduced if the rotation speed of a compressor reduces, an electrical input can be reduced to some extent and the energy efficiency can be improved rather than before. In addition, if the compressor 1 and the brine circulation pump 11 are operated on a single inverter base, it is possible to provide a refrigeration air conditioner that is less expensive and has high energy efficiency.

Moreover, the drive motor of the brine circulation pump 11 can provide an apparatus with higher energy efficiency by using a DC brushless motor whose efficiency in the low rotation range is higher than that of the induction motor. The brine flow rate control has been described with respect to the case where the rotation speed of the brine circulation pump is controlled by an inverter. However, the brine flow rate may be controlled by changing the pump input voltage using a variable voltage source such as a slidac. Good.
Here, the control device 17 performs the pump rotation speed control and the compressor rotation speed control, but may also perform the motor control of the blowers 7 and 16.
Further, the brine circulation pump 11 may be provided anywhere in the brine circuit constituting the secondary side cycle.

  FIG. 4 includes three indoor units 52a, 52b, and 52c, and open / close valves 53a, 53b, and 53c that open and close the brine flow path are provided on the indoor heat exchanger inlet side. The indoor units 52a, 52b, and 52c are connected in parallel, for example, and the brine is circulated by one pump 11. In such a configuration, the indoor units 52a, 52b, and 52c are in operation / stopped state, and therefore, the possibility that the load fluctuates is high. Therefore, by controlling the brine flow rate by changing the number of revolutions of the pump according to the load or the number of revolutions of the compressor, the electrical input can be greatly reduced, and the effect is greater than that of a single indoor unit. Is obtained.

  The same effect can be obtained when a plurality of indoor units are connected in series and the brine flow rate is controlled by a single pump. A similar effect can be obtained by connecting a plurality of pumps in series and changing the rotational speed of each pump to control the brine flow rate.

  Hereinafter, another refrigerating and air-conditioning apparatus according to Embodiment 1 of the present invention will be described. This other embodiment relates to the configuration of the intermediate heat exchanger 10 that exchanges heat between the refrigerant that is the primary heat transfer medium and the brine that is the secondary heat transfer medium. It is the same as that of FIG. In another refrigerating and air-conditioning apparatus of the first embodiment, a plate heat exchanger as shown in FIG. 5 is used for the intermediate heat exchanger 10. FIG. 5 is an exploded perspective view showing a part of the plate heat exchanger, which is formed by stacking a plurality of plate-like plates, and two heat transfer media flow alternately in opposite directions along the plates, for example. A flow path is formed.

  In the figure, reference numeral 18 denotes two plates 18a and 18b fixed to each other, and a flow path A that flows upward in the figure is formed between the two plates 18a and 18b. The four holes provided in the plate 18 pass when the heat transfer medium moves between the plates 18, and the upper and lower holes of the four holes pass through the heat transfer medium flowing through the flow path A. However, the heat transfer medium flowing through the flow path B passes through the upper and lower holes on the near side. In addition, although shown in an exploded manner in the figure, in practice, a plurality of plates 18 are overlapped and fixed, and a channel B that flows downward (arrow 19b) toward the figure is formed in the overlapped portion. Yes. Each of the plates 18a and 18b has, for example, a flat plate shape and a plurality of grooves on the entire surface.

The plate heat exchanger having such a configuration is used as the intermediate heat exchanger 10. For example, the secondary side heat transfer medium brine is circulated in the flow path A, and the primary heat transfer medium medium refrigerant is circulated in the flow path B. Let An arrow 19a in the figure indicates the flow direction of the brine flowing through the flow path A, and 19b indicates the flow direction of the refrigerant flowing through the flow path B. The brine flowing through the flow path A flows through the lower hole from the direction of the arrow 19a, and a part of the brine flows upward between the plates 18 and flows through the upper hole in the direction of the arrow 19a. In addition, the refrigerant flowing through the flow path B flows through the upper hole from the direction of the arrow 19b, and part of the refrigerant flows downward between the plates 18 in the direction of the arrow 19b and flows through the lower hole in the direction of the arrow 19b.
When flowing along the plate 18, the brine and the refrigerant exchange heat with each other.

  As described above, the plate heat exchanger is configured to have a flat plate shape and grooves on the entire surface, and the heat transfer area is large because heat is exchanged partially in the flat plate shape, and the flow of fluid along the blade 18 by the grooves. High heat transfer performance can be obtained. Therefore, the temperature difference between the refrigerant and the brine can be reduced, and the energy efficiency of the refrigeration air conditioner can be improved. That is, during the heating operation, the condensation pressure of the primary side cycle can be reduced, and the electric input of the compressor can be reduced. Further, during the cooling operation, the evaporating pressure of the primary side cycle can be increased, the number of rotations of the compressor can be reduced, and the electric input of the compressor can be reduced.

  Further, in the configuration shown in FIG. 5, the flow direction of the refrigerant and the brine in the plate heat exchanger during heating and cooling is always opposite, and heat exchange is further performed using the temperature difference between the brine and the refrigerant. The heat transfer performance can be improved and the energy efficiency can be further improved.

  In addition, the plate heat exchanger has a smaller internal volume in the heat exchanger than the heat exchanger or the double-pipe heat exchanger that is in contact with the pipes used in the conventional equipment. Refrigerant filling amount can be reduced. For this reason, it is possible to improve safety against refrigerant leakage from the outdoor unit 51 when a combustible refrigerant is used as the refrigerant.

  Further, by making the flow passage cross-sectional area of the brine flow passage 13 in the plate heat exchanger larger than the flow passage cross-sectional area of the refrigerant flow passage 5, the pressure loss of the brine flowing through the enlarged flow passage is reduced and energy efficiency is improved. The safety can be improved by reducing the amount of the refrigerant flowing through the reduced flow path.

  The flow path cross-sectional area at this time is a cross-sectional area of the flow path of the portion that contributes to heat transfer when the heat transfer medium flows in the heat exchanger, and in the case of a plate heat exchanger configured as shown in FIG. , The total cross-sectional area of each of the flow paths in the cross section on the C plane. A specific configuration in which the flow path cross-sectional area of the brine flow path 13 is larger than the flow path cross-sectional area of the coolant flow path 5 is that What is necessary is just to make it larger than the lamination width of the part which distribute | circulates.

In FIG. 5, two plates 18 are fixed to each other to form a flow path A between them. Here, for example, three plates are fixed as plates 18, and two plates formed between them are formed. Both channels may be the channel A. In this case, the configuration of the cross section on the C plane is such that one layer of the channel B is laminated every two layers of the channel A. Therefore, the flow passage cross-sectional area of the brine flow passage 13 can be made larger than the flow passage cross-sectional area of the refrigerant flow passage 5 by allowing the brine to flow through the flow path A and the refrigerant through the flow path B.

  Thus, since the pressure loss of the brine flowing in the plate heat exchanger can be reduced by making the brine flow path cross-sectional area larger than the refrigerant flow path cross-sectional area, the head (head) required for the brine circulation pump 11 is small. Thus, the required input of the brine circulation pump 11 can be reduced.

  On the other hand, since the refrigerant flow passage cross-sectional area is small, the refrigerant volume in the plate heat exchanger is reduced, and the amount of refrigerant necessary for the primary side cycle can be reduced.

Moreover, as a structure of the outdoor unit 51, by arranging a plate heat exchanger at the upper part of the outdoor unit, the outdoor unit of the current direct expansion room air conditioner can be diverted and manufactured at a low manufacturing cost. Can be.
Moreover, if a plate heat exchanger is arrange | positioned in the lower part of an outdoor unit, the gravity center of an outdoor unit will be stabilized and the reliability of the apparatus with respect to an earthquake etc. will improve. Further, in this configuration, the connecting pipe from the compressor 1 and the electric expansion valve 4 to the plate heat exchanger can be shortened, and the refrigerant charge amount in the primary side cycle can be reduced.

  Moreover, the outdoor unit 51 can be made compact by integrating the plate heat exchanger 10 and the brine tank 14.

  Further, another refrigeration air conditioner according to Embodiment 1 of the present invention will be described. 6 is a refrigerant circuit diagram showing another refrigerating and air-conditioning apparatus according to Embodiment 1 of the present invention. The same or similar components as those shown in FIG. Omitted. This other embodiment relates to the flow direction of the heat transfer medium in the use side heat exchanger of the secondary side cycle.

  The indoor heat exchanger 12 of the secondary side cycle is a refrigerant-air heat exchanger that performs heat exchange between the indoor air and the secondary side heat transfer medium, and is, for example, a two-row plate fin heat exchanger. Furthermore, the flow of the brine which is the secondary side heat transfer medium flowing in the heat transfer tube and the flow of the air which is the utilization side heat medium flowing outside the heat transfer tube are configured to face each other. That is, in the indoor heat exchanger 12, indoor air is blown around the heat transfer tube by the indoor blower 16, and the brine flowing in the heat transfer tube exchanges heat with the indoor air flowing therearound. The heat transfer tube is configured so that the brine flows from the downstream side to the upstream side of the indoor air flow in the exchanger 12.

  The brine inlet / outlet temperature difference of the indoor heat exchanger 12 is 5 ° C. or more, and heat exchange is performed by making the brine and air flows counterflow and the brine flow from downstream to upstream of the air flow. The average temperature difference between the indoor air and the brine in the part can be made smaller than that of the parallel flow. For example, when the cooling operation is performed, when the brine inlet temperature in the indoor heat exchanger 12 is 7 ° C., the outlet temperature is about 12 ° C. On the other hand, indoor air flows from the brine outlet side to the inlet side of the indoor heat exchanger 12. Therefore, warm air in the room flows in from the brine outlet side, is cooled to some extent by the brine of about 12 ° C., is gradually cooled while circulating in the indoor heat exchanger 12, and is about 5 ° C. at the brine inlet side. It will be cooled by brine.

  By comprising in this way, the average temperature difference of the brine and refrigerant | coolant in the indoor heat exchanger 12 is made smaller than a parallel flow, heat transfer performance is improved, and energy efficiency is made high as the whole refrigeration air conditioner. it can. In particular, the use of brine as the secondary heat transfer medium is effective because the temperature difference between the inlet side and the outlet side of the indoor heat exchanger 12 is as high as 5 ° C. as described above.

In the other embodiments of the first embodiment, the example in which the indoor heat exchanger 12 is configured by two rows of heat exchangers has been described. However, the present invention is not limited to this, and three rows or four rows or more. The heat exchanger may be used. Further, the heat exchanger may be a heat exchanger having two rows of main portions and a portion of three rows.
Moreover, although the case of the cooling operation has been described in the above specific example, the same applies to the case of the heating operation, so that the brine flows from the downstream side to the upstream side of the indoor air flow in the indoor heat exchanger 12. When the heat transfer tube is configured, the brine having a low temperature and the indoor air having a low temperature exchange heat on the outlet side of the indoor heat exchanger 12, and the room in which the temperature is increased to some extent on the inlet side of the indoor heat exchanger 12 by a brine having a high temperature. Since air exchanges heat, heat can always be efficiently exchanged due to temperature differences, and heat transfer performance can be improved.

  This secondary cycle is a heat transport cycle that transports the cold or warm heat obtained in the primary cycle indoors, and the flow direction of the brine in the indoor heat exchanger 12 is the same in the cooling operation or heating operation. The flow of outdoor air and the flow of brine can be easily configured to be opposite flows. The same applies to the case where the use-side heat medium is not room air but a fluid such as another gas or liquid.

  Further, another refrigeration air conditioner according to Embodiment 1 of the present invention will be described. This other embodiment relates to a refrigerant pipe constituting the primary side cycle and a refrigerant pipe constituting the secondary side cycle, and the refrigerant circuit constituting the refrigeration air conditioner is the same as that of FIG. 1 in the first embodiment, for example. It is.

In this other embodiment, the pipe diameter of the primary cycle is 7.0 mm, the pipe diameter of the secondary cycle is 9.0 mm, and the pipe diameter constituting the secondary cycle is the primary cycle. It is larger than the pipe diameter to improve energy efficiency and reduce the amount of refrigerant.
That is, by increasing the pipe diameter of the secondary side cycle, the pressure loss of the brine flowing through the secondary side cycle can be reduced, so that the head (head) required for the brine circulation pump 11 is reduced, and the brine circulation pump 11 The required electrical input can be reduced. Therefore, a refrigerating and air-conditioning apparatus with high energy efficiency as a whole is obtained, and reducing the power consumption is effective for suppressing global warming.

Furthermore, since the pipe diameter of the primary side cycle is small, the internal volume of the entire pipe can be reduced, and the amount of refrigerant charged in the primary side cycle can be reduced. In particular, when a flammable refrigerant is used as the refrigerant, the amount of the refrigerant can be reduced, so that safety at the time of refrigerant leakage can be improved.
Further, in order to further reduce the pressure loss in the secondary side cycle, for example, the refrigerant pipe can be a smooth pipe.

  Further, another refrigeration air conditioner according to Embodiment 1 of the present invention will be described. This other embodiment includes a refrigerant that is a heat transfer medium in the outdoor heat exchanger 3 that is a heat source side heat exchanger of the primary side cycle and the indoor heat exchanger 12 that is a usage side heat exchanger of the secondary side cycle, and This relates to the heat transfer tubes constituting the brine flow path, and the refrigerant circuit constituting the refrigeration air conditioner is the same as that shown in FIG.

The outdoor heat exchanger 3 is for exchanging heat between the refrigerant and the outside air, and the indoor heat exchanger 12 is for exchanging heat between the brine and the indoor air, and each is composed of, for example, a plate fin heat exchanger. In another embodiment, for example, the heat transfer tube diameter of the indoor heat exchanger 12 is set to 9.52 mm, the heat transfer tube diameter of the outdoor heat exchanger 3 is set to 7.0 mm, and the heat transfer of the indoor heat exchanger 12 is set. The pipe diameter is made larger than the heat transfer pipe diameter of the outdoor heat exchanger 3 to improve energy efficiency and reduce the amount of refrigerant.
That is, by increasing the heat transfer tube diameter of the indoor heat exchanger 12, the pressure loss of the brine flowing through the indoor heat exchanger 12 can be reduced, so that the head (head) required for the brine circulation pump 11 is reduced, and the brine The electric input required for the circulation pump 11 can be reduced. Therefore, a refrigerating and air-conditioning apparatus with high energy efficiency as a whole is obtained, and reducing the power consumption is effective for suppressing global warming.

  Furthermore, since the heat transfer tube diameter of the outdoor heat exchanger 3 is small, the internal volume of the outdoor heat exchanger 3 can be reduced, and the amount of refrigerant charged in the primary side cycle can be reduced. In particular, when a flammable refrigerant is used as the refrigerant, the amount of the refrigerant can be reduced, so that safety at the time of refrigerant leakage can be improved.

  In addition, in this other embodiment, although the structure which made the heat transfer tube diameter of the outdoor heat exchanger 3 smaller than the heat transfer tube diameter of the indoor heat exchanger 12 was demonstrated, it is not restricted to this, Heat transfer tube If the channel cross-sectional area of the outdoor heat exchanger 3 is made smaller than the channel cross-sectional area of the indoor heat exchanger 12, such as shortening the overall length, the pressure loss in the indoor heat exchanger 12 can be reduced and the secondary The electric input required for the brine circulation pump 11 in the side cycle can be reduced, and the amount of refrigerant charged in the primary side cycle can be reduced.

  The cross-sectional area of the flow path at this time means the cross-sectional area of the portion of the heat transfer tube that contributes to heat transfer in the heat exchanger, and the flow of refrigerant or brine as a heat transfer medium from the inlet to the outlet of the heat exchanger When the path is composed of one flow path, it corresponds to the cross-sectional area of the heat transfer tube. In addition, when the heat transfer medium branches from the inlet to the outlet into a plurality of flow paths, the cross-sectional area of the heat transfer tube when the heat transfer medium flowing into the heat exchanger branches and passes almost simultaneously Is the total.

In order to make the flow path cross-sectional area of the indoor heat exchanger 12 larger than the flow path cross-sectional area of the outdoor heat exchanger 3, the size of the heat transfer tube diameter is changed, and the outdoor heat exchanger 3 and the indoor heat exchanger 12 The heat transfer tube diameter may be the same, and the number of refrigerant branches in the indoor heat exchanger 12 may be larger than that in the outdoor heat exchanger 3. For example, the heat transfer tube diameter of both the outdoor and indoor heat exchangers may be 7.0 mm, and the heat transfer tubes may be configured with four branches in the indoor heat exchanger 12 and two branches in the outdoor heat exchanger 3.
Further, for example, the refrigerant pipe in the indoor heat exchanger 12 may be a smooth pipe to further reduce the pressure loss.

  Further, in addition to the configuration of this embodiment, in the flow of brine and room air in the indoor heat exchanger 12 as in the other embodiments, from the downstream side to the upstream side of the flow of room air. If it is comprised so that a brine may flow, the heat-transfer performance in the indoor heat exchanger 12 can be improved, and energy efficiency can further be improved as the whole refrigeration air conditioner.

  In the first to the other embodiments, when a flammable hydrocarbon-based refrigerant such as propane or butane is used as the heat transfer refrigerant in the primary side cycle, the earth such as ozone layer destruction and global warming can be used. It has the effect of not adversely affecting the environment. Particularly in a plurality of other embodiments, there is an effect that the amount of refrigerant in the primary side cycle can be reduced. Therefore, when a flammable refrigerant is used as the refrigerant, reduction of the amount of refrigerant = improves safety and is effective. It is. Further, the refrigerant is not limited to the hydrocarbon-based refrigerant, and a natural refrigerant such as ammonia or ether, or a mixed refrigerant thereof may be used. Moreover, HFC type | system | group fluorocarbon refrigerant | coolants with small global warming coefficients, such as R32 and R152a, or its mixed refrigerant may be sufficient.

  In addition, although brine has been described as the heat transfer medium for the secondary side cycle, any non-combustible medium may be used, such as water, or a medium that does not have flammability and does not adversely affect the global environment. R134a, carbon dioxide, or the like, which is a refrigerant that does not adversely affect the HFC-based global environment, may be used.

  However, when brine or water is used, the safety in the indoor unit is high, a dedicated pump is not required as in the refrigerant, and the characteristics can be utilized. For example, in the case of brine, since it does not freeze even at 0 ° C. or lower, the reliability of the equipment can be improved. In the case of water, it is inexpensive and is usually used at home, and is a medium that conforms to the global environment.

  Further, another refrigeration air conditioner according to Embodiment 1 of the present invention will be described. FIG. 7 is a refrigerant circuit diagram of a primary cycle related to a refrigeration air conditioner according to another embodiment. The same or similar components as those shown in FIG. Description is omitted. The configuration of the secondary side cycle is omitted because it is the same as that shown in FIG. In the figure, reference numerals 21 and 22 denote on-off valves, for example, first and second solenoid valves, 23 a check valve, and 24 a heat exchanger. The check valve 23 blocks the refrigerant flow from the intermediate heat exchanger 10 to the electric expansion valve 4 and allows the refrigerant flow from the electric expansion valve 4 to the intermediate heat exchanger 10 to pass therethrough. With this configuration, a bypass pipe is provided in the refrigerant pipe between the intermediate heat exchanger 10 and the electric expansion valve 4, and this bypass pipe is again connected to the intermediate heat via the first electromagnetic valve 21 and the second electromagnetic valve 22. Connected to the refrigerant pipe between the exchanger 10 and the electric expansion valve 4. The heat exchanger 24 is configured to exchange heat between the bypass piping between the first solenoid valve 21 and the second solenoid valve 22 and the suction-side piping of the compressor 1. In addition, this heat exchanger 24 is comprised with heat exchangers, such as a contact type, a double tube type, or a plate type.

  Next, the operation will be described. In FIG. 7, the refrigerant flow during the heating operation is indicated by a solid line arrow, and the refrigerant flow during the cooling operation is indicated by a broken line arrow. During the heating operation, the first electromagnetic valve 21 and the second electromagnetic valve 22 are opened. The high-temperature and high-pressure refrigerant vapor leaving the compressor 1 passes through the four-way valve 2 and flows into the intermediate heat exchanger 10. The refrigerant that has flowed into the refrigerant flow path 5 in the intermediate heat exchanger 10 is cooled by the brine flowing in the brine flow path 13, condensed and liquefied, and becomes a high-pressure liquid refrigerant and flows out from the intermediate heat exchanger 10. Thereafter, the high-pressure liquid refrigerant flows into the heat exchanger 24 through the first electromagnetic valve 21, is cooled by the refrigerant flowing through the suction-side piping of the compressor 1, passes through the second electromagnetic valve 22, and is electrically expanded. 4 flows in. The liquid refrigerant that has flowed into the electric expansion valve 4 is decompressed by the electric expansion valve 4, becomes a low-pressure gas-liquid two-phase refrigerant, and flows into the outdoor heat exchanger 3 that operates as an evaporator. The low-pressure gas-liquid two-phase refrigerant takes heat from the outside air in the outdoor heat exchanger 3 and evaporates to flow out as a low-pressure vapor refrigerant. After passing through the four-way valve 2, the heat exchanger 24 passes the above bypass pipe. The flowing refrigerant is cooled and sucked into the compressor 1 again.

  Further, during the cooling operation, the first electromagnetic valve 21 and the second electromagnetic valve 22 are closed. The high-temperature and high-pressure refrigerant vapor exiting the compressor 1 passes through the four-way valve 2 and flows into the outdoor heat exchanger 3, where heat is taken away by the outside air, and condensed and liquefied. The high-pressure liquid refrigerant flowing out of the outdoor heat exchanger 3 flows into the electric expansion valve 4 and is reduced in pressure to become a low-pressure gas-liquid two-phase refrigerant, and flows into the intermediate heat exchanger 10 through the check valve 23. To do. The refrigerant that has flowed into the refrigerant flow path 5 in the intermediate heat exchanger 10 is heated by the brine flowing in the brine flow path 13, becomes low-pressure steam, and flows out of the intermediate heat exchanger 10. This low-pressure vapor refrigerant passes through the four-way valve 2, passes through the heat exchanger 24, and is sucked into the compressor 1 again.

  Thus, in this other embodiment, the bypass pipe and the heat exchanger 24 are provided in the primary side cycle, and the intermediate heat exchanger 10 of the outdoor heat exchanger 3 and the intermediate heat exchanger 10 is operated as a condenser. At this time, the heat exchanger 24 exchanges heat between the high-pressure refrigerant on the outlet side of the intermediate heat exchanger 10 and the low-pressure refrigerant on the outlet side of the outdoor heat exchanger 3 that is an evaporator.

  That is, the refrigerant that has exited the intermediate heat exchanger 10 that operates as a condenser during the heating operation is cooled by the suction side piping of the compressor 1, and the refrigerant supercooling degree is taken here. The refrigerant at the outlet of the exchanger 10 can be in a saturated state or a gas-liquid two-phase state. Since the refrigerant state near the outlet of the intermediate heat exchanger 10 is always a gas-liquid two-phase state with high heat transfer characteristics and liquid refrigerant with poor heat transfer characteristics can be eliminated, the heat transfer performance of the entire intermediate heat exchanger is improved. In addition, the energy efficiency of the primary side cycle can be improved.

  Further, since the degree of supercooling of the refrigerant at the inlet of the electronic expansion valve 4 can be sufficiently obtained by the heat exchanger 24, bubbles do not enter the refrigerant flowing into the electric expansion valve 4, and the electric expansion valve 4 It is possible to prevent the generation of abnormal noise in the refrigerant.

  Furthermore, by setting the outlet refrigerant state of the intermediate heat exchanger 10 to a saturated state or a gas-liquid two-phase state, the amount of refrigerant in the intermediate heat exchanger 10 can be reduced, and the amount of refrigerant charged in the primary side cycle can be reduced. In addition, when a flammable refrigerant is used as the refrigerant, safety at the time of refrigerant leakage can be improved.

  In the other embodiment shown in FIG. 7, the example in which the performance improvement when the refrigeration cycle is heating-operated and the generation of abnormal refrigerant noise has been described has been described. However, the configuration of the primary-side cycle shown in FIG. It is also possible to improve the performance at the time and prevent the generation of abnormal refrigerant noise. In the cooling operation, since the outdoor heat exchanger 3 of the outdoor heat exchanger 3 and the intermediate heat exchanger 10 is operated as a condenser, the high-pressure refrigerant on the outlet side of the outdoor heat exchanger 3 and the intermediate heat as an evaporator are used. The heat exchanger 24 is configured to exchange heat with the low-pressure refrigerant on the outlet side of the exchanger 10.

  In FIG. 8, 31 and 32 are on-off valves, for example, third and fourth solenoid valves, and 33 is a check valve. The check valve 33 blocks the refrigerant flow from the outdoor heat exchanger 3 to the electric expansion valve 4 and allows the refrigerant flow from the electric expansion valve 4 to the outdoor heat exchanger 3 to pass therethrough. With this configuration, a bypass pipe is provided in the refrigerant pipe between the outdoor heat exchanger 3 and the electric expansion valve 4, and this bypass pipe is again connected to the outdoor heat via the third electromagnetic valve 31 and the fourth electromagnetic valve 32. It is connected to a refrigerant pipe between the exchanger 3 and the electric expansion valve 4. The heat exchanger 24 is configured to exchange heat between the bypass piping between the third solenoid valve 31 and the fourth solenoid valve 32 and the suction side piping of the compressor 1.

  In the primary side cycle of this configuration, the refrigerant that has exited the outdoor heat exchanger 3 that operates as a condenser during cooling operation is cooled by the low-pressure vapor refrigerant that flows through the suction-side piping of the compressor 1, and the refrigerant subcooling degree is increased here. It is configured to take. For this reason, the refrigerant at the outlet of the outdoor heat exchanger 3 can be in a saturated state or a gas-liquid two-phase state, improving energy efficiency during cooling operation, and generating abnormal noise in the electric expansion valve 4. Generation prevention can be realized. Furthermore, when a flammable refrigerant is used as the refrigerant, a refrigeration air conditioner that can improve safety by reducing the amount of refrigerant can be obtained.

  Further, both the circuit shown in FIG. 7 and the circuit shown in FIG. 8 may be combined, and the circuit may be switched between the heating operation and the cooling operation by switching means such as an on-off valve. If comprised in this way, the improvement of the energy efficiency at the time of heating operation and air_conditionaing | cooling operation, generation | occurrence | production of the abnormal refrigerant | coolant noise in the electric expansion valve 4, and the safety | security improvement by reduction of a refrigerant | coolant amount are realizable.

  Further, another refrigeration air conditioner according to Embodiment 1 of the present invention will be described. FIG. 9 is a refrigerant circuit diagram showing a refrigerating and air-conditioning apparatus according to another embodiment. The same or similar components as those shown in FIG. 1 are denoted by the same reference numerals, and redundant description thereof is omitted. In the figure, 40 is an oil separator provided in the discharge side piping of the compressor 1 in the primary cycle, 41 is a capillary, 42 is an on-off valve, for example, an electromagnetic valve. The bottom of the oil separator 40 is connected to the suction side piping of the compressor 1 via a capillary tube 41 and a solenoid valve 42.

  Lubricating oil sealed in the compressor 1 for lubrication of the compressor sliding portion circulates in the primary cycle together with the refrigerant. When there is a large amount of lubricating oil circulating in the primary side cycle, a part of the circulation in the primary side cycle is performed in the piping and heat exchange section through which the gas-liquid two-phase refrigerant or gas refrigerant flows. Lubricating oil adheres to the inside of the refrigerant pipe. For this reason, an increase in refrigerant pressure loss and a decrease in heat transfer performance of the heat exchanger are caused, and as a result, the energy efficiency of the primary side cycle is reduced. As the lubricating oil stored in the compressor 1, mineral oil or the like that dissolves in a combustible refrigerant is used. In other words, when the refrigerant is a hydrocarbon-based refrigerant, the mutual solubility with lubricating oil such as mineral oil is high, and a large amount of refrigerant dissolves in the lubricating oil inside the compressor, reducing the viscosity of the lubricating oil. The oil discharge amount from the machine 1 tends to increase.

  The pipes on which the lubricant is likely to adhere are pipes and heat exchange sections through which a gas-liquid two-phase refrigerant or a gas refrigerant flows as described above, and there are some differences between the cooling operation and the heating operation. From the compressor when operating the refrigeration cycle to the vicinity of the outlet of the condenser, the refrigerant piping from the expansion device to the evaporator and the suction side of the compressor.

  Therefore, in this other embodiment, the lubricating oil mixed in the fluid discharged from the compressor 1 is separated by the oil separator 40, and the refrigerant is circulated through the normal refrigerant pipe to the four-way valve 2, Lubricating oil is collected at the bottom of the oil separator 40. Normally, the refrigerant is in a gas state on the discharge side of the compressor 1, and the liquid lubricant and the refrigerant gas are smoothly separated. The lubricating oil accumulated in the oil separator 40 is controlled by the capillary 41 so that the return amount does not become abrupt by opening the electromagnetic valve 42 continuously or periodically or irregularly. Return to the compressor 1 from the side piping.

  In this way, by returning the lubricating oil that has flowed out to the discharge side piping of the compressor 1 by the oil separator 40 to the compressor 1, the amount of lubricating oil circulating in the primary side cycle is greatly reduced. The amount of lubricating oil that adheres to the inside can be greatly reduced. As a result, an increase in refrigerant pressure loss and a decrease in heat transfer performance of the heat exchanger can be suppressed, and a refrigeration air conditioner that can prevent a decrease in energy efficiency is obtained.

  Moreover, by reducing the amount of lubricating oil circulating in the primary side cycle by the oil separator 40, the amount of lubricating oil present in the piping of the primary side cycle can also be reduced, and as a result, sealed in the compressor. The amount of lubricating oil can also be reduced. By reducing the initial amount of lubricating oil enclosed in the compressor, the amount of refrigerant that is dissolved in the lubricating oil is reduced, so that the amount of refrigerant charged to the primary cycle can be further reduced, and a combustible refrigerant is used as the refrigerant. The safety at the time of refrigerant leakage is further improved. Also, since the initial amount of the lubricating oil can be reduced, the cost of the lubricating oil can be reduced, and an inexpensive refrigeration air conditioner can be provided.

Further, another refrigeration air conditioner according to Embodiment 1 of the present invention will be described. This other embodiment relates to an improvement in energy efficiency when a hydrocarbon-based refrigerant is used as the primary side heat transfer medium. The configuration of the refrigerating and air-conditioning apparatus according to the other embodiment is the same as that in FIG.
In the operation control of the refrigeration cycle, the electric expansion valve 4 normally has its opening degree so that, for example, the refrigerant supercooling degree at the outlet of the condenser becomes a predetermined temperature even if the rotation speed of the compressor 1 changes. Is controlled. The degree of subcooling of the outlet of the condenser is detected by detecting the refrigerant temperature and pressure at the outlet of the condenser, for example.

  In this other embodiment, in the primary cycle, a hydrocarbon-based refrigerant is circulated as the refrigerant, and the outlet of the heat exchanger that operates as a condenser, that is, the outlet of the intermediate heat exchanger 10 during the heating operation and the cooling operation. The opening degree of the electric expansion valve 4 is controlled so that the refrigerant supercooling degree (refrigerant saturation temperature−outlet refrigerant temperature) at the outlet of the outdoor heat exchanger 3 is in the range of 0 ° C. to 10 ° C., for example, 5 ° C. . This is controlled to about 15 ° C. when the refrigerant R22 (HCFC22) of the conventional room air conditioner is used, but because the specific heat of the liquid refrigerant of the hydrocarbon refrigerant R290 (propane) is larger than that of the refrigerant R22. This is because, in R290, the efficiency of the primary side cycle is higher in R290 than in R22 when the condenser outlet supercooling degree is reduced.

  In FIG. 10, the horizontal axis indicates the condenser outlet subcooling degree, and the vertical axis indicates the energy efficiency of the primary cycle. The solid line in the figure indicates the characteristic of R290, and the broken line indicates the characteristic of R22. The constant pressure specific heat of the saturated liquid at 50 ° C. is 3.1 kJ / (kg · K) for R290 and 1.4 kJ / (kg · K) for R22, and R290 is larger. For this reason, the amount of heat necessary to obtain the same degree of supercooling is larger in R290 than in R22, and therefore the degree of supercooling that maximizes the energy efficiency of the primary side cycle is smaller in R290 than in R22. Become. FIG. 10 shows this state. While the current R22 has the maximum energy efficiency in the range of 10 ° C. to 20 ° C., the R290 has the maximum in the range of 0 ° C. to 10 ° C. . Therefore, in the primary side cycle using the hydrocarbon refrigerant R290, the primary side cycle is operated in a highly energy efficient state by controlling the degree of condenser supercooling in the range of 0 to 10 ° C., preferably about 5 ° C. be able to.

  In addition, since the hydrocarbon-based refrigerant is flammable, it is safer to reduce the charging amount as much as possible. By controlling the degree of subcooling of the condenser in the primary cycle in the range of 0 to 10 ° C, Since the amount of refrigerant can be reduced, and as a result, the amount of refrigerant charged in the primary cycle can be reduced, the safety at the time of refrigerant leakage can also be improved.

Further, another refrigeration air conditioner according to Embodiment 1 of the present invention will be described. In another embodiment, even if the refrigerant leaks from the primary side cycle, it is attempted to detect it early.
Here, for example, an odorant is added as an identifying agent for identifying the location where the refrigerant has leaked to the lubricating oil sealed for lubricating the compressor sliding portion of the primary side cycle. For this reason, in the unlikely event that the refrigerant leaks from the primary side cycle, the lubricating oil also leaks together with the refrigerant, so that the smell can easily know the refrigerant leakage and the lubricating oil leakage, and the user can take appropriate measures. Can be applied. Also, when repairing a refrigeration air conditioner in which a leak has occurred, the leak location can be easily identified, so that appropriate processing can be quickly performed. In particular, when a flammable refrigerant is used as the refrigerant, it is possible to prevent the occurrence of a major accident and improve safety by detecting and responding to the leakage at an early stage.

In this embodiment, an example in which an odorant is added as an identification agent to the lubricating oil has been shown. However, a coloring agent is added to the lubricating oil, and the leakage of the refrigerant is caused by the color of the lubricating oil leaking together with the refrigerant. Even if it can be detected, the same effect is exhibited. For example, as a specific colorant, for example, a colorant, a red colorant is used, and the following are typical components.
Chemicals: Azo, diazo compounds (mixtures and dyes listed below)
Reference number of existing chemical substances under the Chemical Substances Control Regulation Law
Class 5 3087 (Solvent Red 23)
Class 5 5049 (Solvent Orange 73)
Ingredients and content: Dye ingredient 60-70%
Xylene (solvent) 30-40%
The chemical structure of these azo and diazo dyes has an aromatic ring and —N═N— bond in the molecule.

In addition, since an identification agent melt | dissolves and uses it in lubricating oil, it needs to have a property melt | dissolved in lubricating oil. In the case of an odorant, it is desirable that the odor generated when it is dissolved in a lubricating oil is not a very good scent, and a special odor is not desirable as it is caused by other causes. The same applies to the coloring agent, and the location where the lubricating oil leaks can be easily detected by the color. Therefore, it is desirable to make the color conspicuous around the apparatus in order to check where it has leaked.
Further, a sensor for detecting the smell of the identification agent or the like may be provided in the outdoor unit 51, and this sensor may automatically detect leakage of the lubricating oil and issue an alarm, for example. In this case, any identifying agent such as odor or color that can be detected by the sensor may be used, and it can be set to detect even a small amount of leak that cannot be detected by humans at an early stage.

  Moreover, although this embodiment demonstrated the case where mineral oil was used as lubricating oil, it is not restricted to this, Synthetic oils, such as alkylbenzene, ester oil, ether oil, and PAG oil, may be sufficient.

  Further, in a plurality of other embodiments, the intermediate heat exchanger 10 is used as an air-refrigerant heat exchanger to perform indoor air-conditioning, that is, to a refrigeration air-conditioning apparatus having only a primary cycle. it can. At this time, the outdoor heat exchanger 3 that is a heat source side heat exchanger corresponds to the first heat exchanger, the intermediate heat exchanger 10 corresponds to the second heat exchanger, and either the first heat exchanger or the second heat exchanger is used. One of them is operated as an evaporator, and the other is operated as a condenser to constitute a refrigeration cycle, and a combustible refrigerant is circulated as a refrigerant, and cold or hot heat is utilized in the evaporator or the condenser.

It is a refrigerant circuit figure which shows the refrigerating air conditioning apparatus by Embodiment 1 of this invention. It is a graph which shows the relationship between the brine flow volume and electric input of the refrigerating air conditioner by Embodiment 1 of this invention. It is a flowchart which shows the process sequence of pump rotation speed control of the refrigerating air conditioner by Embodiment 1 of this invention. It is a refrigerant circuit figure which shows the other example of the refrigerating air conditioner by Embodiment 1 of this invention. It is a perspective view which decomposes | disassembles and shows a part of other intermediate | middle heat exchanger of the refrigerating air conditioning apparatus by Embodiment 1 of this invention. It is a refrigerant circuit diagram which shows the other refrigeration air conditioning apparatus by the refrigeration air conditioning apparatus by Embodiment 1 of this invention. It is a refrigerant circuit diagram which shows the other refrigeration air conditioning apparatus by the refrigeration air conditioning apparatus by Embodiment 1 of this invention. It is a refrigerant circuit figure which shows the other example of the refrigerating air conditioner by Embodiment 1 of this invention. It is a refrigerant circuit diagram which shows the other refrigeration air conditioning apparatus by the refrigeration air conditioning apparatus by Embodiment 1 of this invention. It is a characteristic view which shows the relationship between the condenser exit supercooling degree of the other refrigerating air-conditioning apparatus by Embodiment 1 of this invention, and a primary side cycle efficiency.

Explanation of symbols

  1 compressor, 3 heat source side heat exchanger (first heat exchanger), 4 expansion device, 10 intermediate heat exchanger (second heat exchanger), 11 pump, 12 use side heat exchanger, 15 flow rate variable mechanism, 17 controller, 24 heat exchanger, 40 oil separator.

Claims (8)

Compressor, heat source side heat exchanger, expansion device, and intermediate heat exchanger are connected in sequence, and the primary side cycle for circulating the primary side heat transfer medium, the pump, the use side heat exchanger, and the intermediate heat exchanger are connected in sequence. And a secondary cycle for circulating the secondary heat transfer medium, heat exchange between the primary heat transfer medium and the secondary heat transfer medium in the intermediate heat exchanger, In the refrigeration air conditioner configured to exchange heat between the secondary side heat transfer medium and the use side heat medium, the primary side heat transfer medium is a flammable refrigerant, and the secondary side heat transfer medium is a nonflammable medium. In addition, the compressor and the pump are detected by changing the number of revolutions of the pump by detecting the electric input of the compressor and the pump using the preset set value as the number of revolutions of the pump. The electrical input of the A control method for a refrigerating and air-conditioning apparatus, wherein the pump is operated at the number of revolutions when the sum of the electrical inputs of the compressor and the pump is reduced by detecting the electrical input at the number of revolutions. The control method for a refrigerating and air-conditioning apparatus according to claim 1, wherein the preset set value is a value corresponding to a rotational speed of the compressor or a load on the use side heat exchanger. 2. The refrigeration air conditioner according to claim 1, wherein the secondary side heat transfer medium flows from a downstream side to an upstream side of the flow of the usage side heat medium in the usage side heat exchanger. The flow path cross-sectional area of the secondary side heat transfer medium flowing in the use side heat exchanger is made larger than the flow path cross section of the primary side heat transfer medium flowing in the heat source side heat exchanger. Item 4. The refrigeration air conditioner according to item 3. When operating either the heat source side heat exchanger or the intermediate heat exchanger as an evaporator and the other as a condenser, heat the high pressure refrigerant on the outlet side of the condenser and the low pressure refrigerant on the outlet side of the evaporator. 2. The refrigeration air conditioner according to claim 1, further comprising a heat exchanger to be exchanged. The lubricating oil stored in the compressor uses oil that dissolves in the flammable refrigerant, and is provided with an oil separator that returns the oil discharged to the discharge side piping of the compressor to the compressor. 2. The refrigeration air conditioner according to claim 1. When one of the heat source side heat exchanger and the intermediate heat exchanger is operated as a condenser and the other as an evaporator, the refrigerant supercooling degree at the outlet of the condenser is in the range of 0 ° C to 10 ° C. 2. The refrigeration air conditioner according to claim 1, wherein the throttle device is adjusted. 2. The refrigerating and air-conditioning apparatus according to claim 1, wherein an identification agent for identifying a portion where the combustible refrigerant has leaked is added to the lubricating oil of the compressor.

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