JP2016080179A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner which is cheap and has a plurality of refrigeration cycles capable of performing efficient operation.SOLUTION: The air conditioner includes: an upstream side refrigeration device R1 in which a compressor 1a, a four-way valve 2a, an exhaust heat side heat exchanger 3a, an expansion device 4a and a utilization side heat exchanger 5a are connected by a refrigerant pipeline h4; and a downstream side refrigeration device R2 in which a compressor 1b, a four-way valve 2b, an exhaust heat side heat exchanger 3b, an expansion device 4b and a utilization side heat exchanger 5b are connected by a refrigerant pipeline h5. A flow passage h1 of a heat load medium of the utilization side heat exchangers 5a, 5b is connected to the upstream side refrigeration device R1 and the downstream side refrigeration device R2 in series in this order. The exhaust heat side heat exchanger 3a of the upstream side refrigeration device R1 and the exhaust heat side heat exchanger 3b of the downstream side refrigeration device R2 have the same or almost the same heat exchange capacity. The operation capacity of the compressor 1b on the downstream side is larger than the operation capacity of the compressor 1a on the upstream side.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an air conditioner.

  Conventionally, an air conditioner that performs air conditioning is described in Patent Document 1. The air conditioner described in Patent Literature 1 connects the heat load media of two refrigeration cycles to each use side heat exchanger in series. And it is described that a high-efficiency operation can be achieved by making the operating capacity of the upstream compressor of the heat load medium larger than the operating capacity of the downstream compressor.

Japanese Patent No. 4999529

  By the way, the conventional air conditioner disclosed in Patent Document 1 increases the operating capacity of the compressor in the upstream refrigeration cycle of the heat load medium to increase the efficient operating ratio on the upstream side, thereby increasing the overall heat source apparatus (air It is said that the efficiency of the entire harmony machine will be improved.

  In the case of cooling operation, since the upstream refrigeration cycle operates at a high evaporation temperature, the upstream refrigerant circulation rate increases and the high-pressure pressure rises, so the capacity of the heat exchanger on the exhaust heat side needs to be increased. . Therefore, there is a problem that the heat transfer area increases due to an increase in the capacity of the heat exchanger, the heat exchanger becomes larger, and the product size of the heat source device becomes larger. When the capacity of the heat exchanger on the exhaust heat side cannot be increased, there is a problem that the high pressure increases and the compressor operates at high speed, and the efficiency (COP: Coefficient Of Performance) decreases due to an increase in power consumption.

  In the case of heating operation, since the condensation temperature of the upstream refrigeration cycle is low, the heat exchange amount of the evaporation side heat exchanger increases. Therefore, it is necessary to increase the capacity of the heat exchanger on the exhaust heat side, and like the cooling operation, the heat transfer area of the heat exchanger increases, the heat exchanger becomes larger, and the product size of the heat source machine increases. There are challenges. When the capacity of the heat exchanger on the exhaust heat side cannot be increased, there is a problem that the low pressure is lowered, the compressor is operated at high speed, and the efficiency is reduced due to the increase in power consumption.

  In view of the above circumstances, an object of the present invention is to provide an inexpensive air conditioner having a plurality of refrigeration cycles that can be operated efficiently.

  In order to solve the above problems, an air conditioner according to a first aspect of the present invention includes an upstream refrigeration system in which a compressor, a four-way valve, an exhaust heat side heat exchanger, an expansion device, and a use side heat exchanger are connected by a refrigerant pipe. And a downstream refrigeration unit to which a compressor, a four-way valve, an exhaust heat side heat exchanger, an expansion device, and a use side heat exchanger are connected by a refrigerant pipe, and the flow of the heat load medium of the use side heat exchanger The upstream refrigeration device and the downstream refrigeration device are connected in series, and the exhaust heat side heat exchanger of the upstream refrigeration device and the exhaust heat side heat exchanger of the downstream refrigeration device are equivalent or The operating capacity of the compressor on the downstream side is larger than the operating capacity of the compressor on the upstream side.

  An air conditioner according to a second aspect of the present invention includes a compressor, a four-way valve, an exhaust heat side heat exchanger, an expansion device, and an upstream side refrigeration device to which a use side heat exchanger is connected by a refrigerant pipe, a compressor, and a four way valve An exhaust heat side heat exchanger, an expansion device, and a downstream side refrigeration device to which a usage side heat exchanger is connected by a refrigerant pipe, and the flow path of the heat load medium of the usage side heat exchanger is the upstream side refrigeration device And the downstream refrigeration unit are connected in series, and the exhaust heat side heat exchanger of the upstream refrigeration unit and the exhaust heat side heat exchanger of the downstream refrigeration unit have heat exchange capacities that are equivalent or close to equivalent. And the temperature of the heat load medium at the outlet of the downstream use side heat exchanger and the temperature of the heat load medium between the downstream use side heat exchanger and the upstream use side heat exchanger. The difference from a certain intermediate temperature is the difference between the intermediate temperature and the temperature of the heat load medium at the inlet of the upstream use side heat exchanger. The difference to be approximately the same.

  An air conditioner according to a third aspect of the present invention includes a plurality of refrigeration apparatuses in which a compressor, a four-way valve, an exhaust heat side heat exchanger, an expansion device, and a use side heat exchanger are connected by a refrigerant pipe. The flow path of the heat load medium of the use side heat exchanger is connected in series in order, the exhaust heat side heat exchanger of each refrigeration apparatus has an equivalent or nearly equivalent heat exchange capacity, The operating capacity of the compressor of each refrigeration apparatus increases as it goes from the upstream side to the downstream side.

  According to the present invention, an inexpensive air conditioner having a plurality of refrigeration cycles that can be operated efficiently can be realized.

The cycle system diagram of the air conditioner concerning the present invention. (a) is a diagram of the relationship between the heat load medium and refrigerant temperature on the upstream side and downstream side of the use side heat exchanger in the cooling operation, and (b) is the diagram on the upstream side and downstream side of the use side heat exchanger in the heating operation. The relationship diagram of a heat load medium and refrigerant | coolant temperature. The refrigeration cycle system diagram of the air conditioner according to Embodiment 2 of the present invention. The refrigeration cycle system diagram of the air conditioner according to Embodiment 3 of the present invention. The refrigeration cycle system diagram of an example of the air conditioner according to the third embodiment. The refrigeration cycle system diagram of the air conditioner according to Embodiment 4 of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
<< Embodiment 1 >>
Embodiment 1 of an air conditioner of the present invention will be described with reference to FIGS.
FIG. 1 shows a cycle system diagram of an air conditioner according to the present invention.

The air conditioner C of Embodiment 1 is an air conditioner that performs air conditioning that includes a plurality of refrigeration cycles.
The air conditioner C includes two refrigeration cycles, an upstream refrigeration cycle R1 and a downstream refrigeration cycle R2.
In the upstream refrigeration cycle R1, a compressor 1a, a four-way valve 2a, an exhaust heat side heat exchanger 3a, an expansion device 4a, a use side heat exchanger 5a, and an accumulator 6a are connected via a pipe h4.

In the downstream side refrigeration cycle R2, as in the upstream side refrigeration cycle R1, the compressor 1b, the four-way valve 2b, the exhaust heat side heat exchanger 3b, the expansion device 4b, the use side heat exchanger 5b, and the accumulator 6b are connected to the pipe h5. Connected through.
In FIG. 1, the solid lines of the four-way valves 2a and 2b indicate the refrigerant flow during the cooling operation, and the dotted lines indicate the refrigerant flow during the heating operation.
Moreover, the solid line arrow added to the pipes h4 and h5 in FIG. 1 indicates the flow of the refrigerant during the cooling operation, and the dotted line arrow indicates the refrigerant flow during the heating operation.

  The heat load medium flow path of the utilization side heat exchanger 5a of the upstream refrigeration cycle R1 and the heat load medium flow path of the utilization side heat exchanger 5b of the downstream refrigeration cycle R2 are connected in series via the pipe h3. Has been. The heat load medium is configured to pass through the pipe h1 and flow from the upstream use side heat exchanger 5a to the downstream use side heat exchanger 5b. The heat load medium is a heat medium that bears cooling and heating of the air conditioner C.

Each of the compressors 1a and 1b includes a scroll compressor, a rotary compressor, a screw compressor, or the like, a compressor having a variable operating capacity, a compressor having a fixed operating capacity, or the like.
The use side heat exchangers 5a and 5b are configured by a laminated plate heat exchanger, a shell and tube heat exchanger, a double tube heat exchanger, and the like.
A temperature sensor s1 such as a thermistor for measuring the temperature of the heat load medium is installed in the pipe h2 at the inlet of the use side heat exchanger 5a of the upstream refrigeration cycle R1.

A temperature sensor s2 such as a thermistor is installed in the pipe h1 between the upstream refrigeration cycle R1 and the downstream refrigeration cycle R2.
A temperature sensor s3 such as a thermistor for measuring the temperature of the heat load medium is installed in the pipe h3 at the outlet of the use side heat exchanger 5b of the downstream side refrigeration cycle R2.

  A pressure sensor s4 is provided on the outlet side of the upstream compressor 1a, and a pressure sensor s5 is provided on the outlet side of the downstream compressor 1b.

  As the upstream exhaust heat side heat exchanger 3a and the downstream exhaust heat side heat exchanger 3b, heat exchangers having heat exchange capacities equivalent or close to equivalent are used. Therefore, the exhaust heat side heat exchangers 3a and 3b have an advantage that the same heat exchanger can be used.

The air conditioner C is controlled by a control device such as a controller (not shown).
Specifically, detection signals from temperature sensors s1, s2, s3, pressure sensors s4, s5, and the like are input to the control device. Control signals for controlling the compressors 1a and 1b, the four-way valves 2a and 2b, the expansion devices 4a and 4b, and the like are output from the control device to each device.

<Cooling operation>
In the cooling operation indicated by the solid arrow in FIG. 1, in the upstream refrigeration cycle R1, the high-temperature and high-pressure gas refrigerant compressed by the compressor 1a passes through the flow path (shown by the solid line) of the four-way valve 2a and is on the exhaust heat side. Heat is dissipated by the heat exchanger 3a and condensed to form a liquid refrigerant having a normal temperature and a high pressure. The room-temperature and high-pressure liquid refrigerant is decompressed by the expansion device 4a to become a low-temperature and low-pressure liquid refrigerant, and is vaporized by heat exchange with the heat load medium sent from the pipe h2 in the use-side heat exchanger 5a. It becomes a refrigerant and returns to the compressor 1a. In the use-side heat exchanger 5a, the low-temperature and low-pressure liquid refrigerant absorbs heat from the heat load medium by latent heat of vaporization and cools the heat load medium.

  If the heat load medium is water, it is cooled by heat exchange in the use side heat exchanger 5a of the upstream side refrigeration cycle R1, and cold water is generated. And it flows in into the utilization side heat exchanger 5b of downstream refrigeration cycle R2 through the piping h1.

In the downstream refrigeration cycle R2, in the cooling operation, as shown by the solid line arrow in FIG. 1, the high-temperature and high-pressure gas refrigerant compressed by the compressor 1b passes through the flow path shown by the solid line of the four-way valve 2b and is exhausted. The side heat exchanger 3b dissipates heat and condenses into a liquid refrigerant having a normal temperature and a high pressure.
The room-temperature and high-pressure liquid refrigerant is decompressed by the expansion device 4b to become a low-temperature and low-pressure liquid refrigerant. In the use-side heat exchanger 5b, the refrigerant is evaporated by exchanging heat with the heat load medium sent from the pipe h1. And return to the compressor 1b.

The low-temperature and low-pressure liquid refrigerant further absorbs heat from the heat load medium cooled in the upstream use side heat exchanger 5a by the latent heat of vaporization in the use side heat exchanger 5b, thereby cooling the heat load medium.
As described above, the cold load water generated in the upstream refrigeration cycle R1 flows into the downstream refrigeration cycle R2 and is further cooled, thereby generating cold water having a desired set temperature.

<Heating operation>
In the heating operation indicated by the broken line arrows in FIG. 1, in the upstream refrigeration cycle R1, the high-temperature and high-pressure gas refrigerant compressed by the compressor 1a passes through the flow path indicated by the dotted line of the four-way valve 2a and uses side heat exchange. The vessel 5a exchanges heat with the heat load medium to dissipate heat and condense, and becomes a liquid refrigerant at room temperature and high pressure. The room-temperature and high-pressure liquid refrigerant is decompressed by the expansion device 4a to become a low-temperature and low-pressure liquid refrigerant. The low-temperature and low-pressure liquid refrigerant is evaporated by the exhaust heat side heat exchanger 3a to become a low-temperature and low-pressure gas refrigerant and returns to the compressor 1a.

If the heat load medium is water, it is heated by heat exchange in the use side heat exchanger 5a of the upstream refrigeration cycle R1 to generate hot water. The hot water flows into the use side heat exchanger 5b of the downstream side refrigeration cycle R2 through the pipe h1.
In the downstream refrigeration cycle R2, in the case of heating operation, as indicated by the broken line arrow, the high-temperature and high-pressure gas refrigerant compressed by the compressor 1b passes through the flow path indicated by the dotted line of the four-way valve 2b, and the use side heat exchanger 5b exchanges heat with the heat load medium, dissipates heat, condenses, and becomes a liquid refrigerant at room temperature and high pressure. The room-temperature and high-pressure liquid refrigerant is decompressed by the expansion device 4b to become a low-temperature and low-pressure liquid refrigerant. The low-temperature and low-pressure liquid refrigerant is evaporated by the exhaust heat side heat exchanger 3b to become a low-temperature and low-pressure gas refrigerant and returns to the compressor 1b.
In the downstream refrigeration cycle R2, the hot water flowing into the downstream use side heat exchanger 5b through the pipe h1 is heated by heat exchange in the use side heat exchanger 5b, and the temperature further rises to a desired setting. Hot water of temperature is produced.

<Relationship between heat load medium and refrigerant temperature on upstream / downstream side of use side heat exchangers 5a and 5b in cooling operation>
FIG. 2 (a) shows a relationship diagram between the heat load medium on the upstream side and the downstream side of the use side heat exchanger in the cooling operation and the refrigerant temperature, and FIG. 2 (b) shows the use side heat exchange in the heating operation. The relationship diagram of the heat load medium and the refrigerant temperature on the upstream side and downstream side of the container is shown. In FIG. 2, the solid line arrows indicate the temperature of the refrigerant in the use side heat exchangers 5a and 5b, and the broken line arrows indicate the temperature of the heat load medium in the use side heat exchangers 5a and 5b.

  In the cooling operation shown in FIG. 2 (a), the use side heat exchanger 5a of the upstream side refrigeration cycle R1 has a high cold water temperature, and therefore the evaporation temperature of the refrigerant is high. On the other hand, the use side heat exchanger 5b of the downstream side refrigeration cycle R2 has a cold water temperature lower than that of the upstream use side heat exchanger 5a, and thus the evaporation temperature of the refrigerant is lowered.

  Therefore, when the upstream and downstream compressors 6a and 6b have the same operating capacity, the upstream refrigeration cycle R1 has a higher evaporation temperature than the downstream refrigeration cycle R2, and therefore the specific volume of the suction portion of the compressor 1a. (Volume occupied by unit mass) is reduced, the amount of refrigerant circulation is increased, and the cooling capacity is increased. Further, when the evaporation temperature is high, the suction pressure of the compressor 1a increases, and the pressure difference between the high pressure and the low pressure of the refrigerant becomes small. Therefore, the compressor 1a can be operated at a relatively low speed, and the power consumption can be reduced. At this time, the amount of heat exchange in the upstream exhaust heat side heat exchanger 3a is increased due to an increase in the amount of refrigerant circulation compared to the exhaust heat side heat exchanger 3b in the downstream refrigeration cycle R2.

For example, the heat exchange amount Q in the heat exchanger is expressed by the following equation.
Heat exchange amount Q = K ・ A ・ ΔT (1)
Here, K is the heat transmissivity in the heat exchanger, A is the heat transfer area in the heat exchanger, and ΔT is the temperature difference between the water (heat medium) flowing through the refrigeration cycles R1 and R2 and the refrigerant.
The temperature difference ΔT1 between water and refrigerant in the use side heat exchanger 5a of the upstream refrigeration cycle R1 and the temperature difference ΔT2 between water and refrigerant in the use side heat exchanger 5b of the downstream refrigeration cycle R2 are as follows: Become a relationship.

Assuming that the temperature of the refrigerant in the upstream refrigeration cycle R1 is equal to the temperature of the refrigerant in the downstream refrigeration cycle R2, the temperature of water at the inlet of the use side heat exchanger 5a of the upstream refrigeration cycle R1 is the downstream refrigeration cycle R2. Since it is higher than the temperature of the water at the entrance to the use side heat exchanger 5b, the relationship ΔT1> ΔT2 is established.
Therefore, from equation (1), the heat exchange amount Q is such that the heat exchange amount Q1 of the upstream refrigeration cycle R1 is greater than the heat exchange amount Q2 of the downstream refrigeration cycle R2.

  For this reason, the amount of heat exhausted by the exhaust heat side heat exchanger 3a of the upstream refrigeration cycle R1 is large and cannot be exhausted sufficiently, and the high pressure side of the compressor 1a becomes high pressure. Therefore, the compressor 1a rotates at a high speed and power consumption increases. At this time, since the heat exchange performance of the upstream exhaust heat side heat exchanger 3a is equal to the heat exchange performance of the downstream exhaust heat side heat exchanger 3b, heat exchange of the downstream exhaust heat side heat exchanger 3b is performed. The amount is considered to be in a state of reserve. Therefore, in order to sufficiently exhaust heat in the upstream exhaust heat side heat exchanger 3a, it is necessary to increase the capacity.

Therefore, in this embodiment, the operating capacity of the compressor 6b of the downstream refrigeration cycle R2 is made larger than the operating capacity of the compressor 6a of the upstream refrigeration cycle R1, and the heat exchange capacity between the upstream side and the downstream side is balanced ( Equal or close to equal).
When the same cooling capacity is provided on the upstream side and the downstream side, the operating capacity of the upstream compressor 6a is reduced compared to the case where the operating capacity of the upstream and downstream compressors 6a and 6b is the same. The operating capacity of the downstream compressor 6b is increased.

  Since the upstream refrigeration cycle R1 has decreased the operating capacity (refrigerant discharge capacity) of the compressor 1a, the high pressure of the refrigerant has decreased, and the downstream refrigeration cycle R2 has increased the operating capacity of the compressor 1b, so that the high pressure has To rise. Therefore, the heat exchange amount of the upstream exhaust heat side heat exchanger 3a decreases and the heat exchange amount of the downstream exhaust heat side heat exchanger 3b increases. Therefore, the upstream and downstream exhaust heat side heat exchangers The capacity of 3a and 3b can be used efficiently.

  More specifically, the intermediate temperature of the heat load medium in the pipe h1 between the upstream refrigeration cycle R1 and the downstream refrigeration cycle R2 increases by increasing the operating capacity of the compressor 1b of the downstream refrigeration cycle R2. Therefore, the evaporation temperature of the downstream refrigeration cycle R2 rises, the specific volume of the suction portion of the downstream compressor 1b decreases, the refrigerant circulation rate increases, the cooling capacity increases, and the efficiency improves.

  On the other hand, in the upstream side refrigeration cycle R1, since the intermediate temperature of the heat load medium on the outlet side of the use side heat exchanger 5a is increased, the heat exchange amount of the exhaust heat exchanger 3a on the upstream side is reduced, and the upstream side It becomes possible to fit in the heat exchange capacity of the exhaust heat exchanger 3a. Therefore, the high pressure of the refrigerant in the upstream refrigeration cycle R1 is suppressed from increasing, and the upstream compressor 6a can be prevented from operating at high speed.

As a result, the efficiency of the entire heat source unit (air conditioner C) is such that the upstream side refrigeration cycle R1 and the downstream side refrigeration cycle R2 are efficient even if the operating capacity of the downstream use side heat exchanger 5b is low. Since it works well, the overall efficiency of the heat source machine will increase.
Here, in FIG. 2 (a), the refrigerant rises in the vicinity of the outlets of the upstream and downstream use side heat exchangers 5a and 5b when the liquid refrigerant enters the compressors 6a and 6b. There is a risk of damage. This is because the refrigerant is heated by adjusting with the expansion devices 4a and 4b to be a low-pressure gas refrigerant and put into the compressor 6a.

<Example of cooling operation>
An example of the cooling operation shown in FIG.
The temperature of the heat load medium water at the inlet to the utilization side heat exchanger 5a of the upstream refrigeration cycle R1 is 14 ° C., and the temperature at the outlet to the utilization side heat exchanger 5b of the downstream refrigeration cycle R2 is as follows. Consider the case of controlling to 7 ° C. That is, the temperature of the cooling water generated in the refrigeration cycles R1 and R2 is 7 ° C.

  Therefore, on the premise that the same cooling performance is obtained in the utilization side heat exchanger 5a of the upstream refrigeration cycle R1 and the utilization side heat exchanger 5b of the downstream refrigeration cycle R2, the utilization side heat exchanger 5a of the upstream refrigeration cycle R1 is obtained. The temperature of the produced water at the outlet of 10.5 ° C. (= (14−7) / 2).

When the refrigerant discharge amount of the compressor 1a of the upstream refrigeration cycle R1 and the refrigerant discharge amount of the compressor 1b of the downstream refrigeration cycle R2 are controlled equally, the intermediate temperature between the upstream refrigeration cycle R1 and the downstream refrigeration cycle R2 is controlled. As described above, since the evaporating temperature of the upstream refrigerant is higher than the evaporating temperature of the downstream refrigerant, the upstream efficiency is higher than that of the downstream side.
Therefore, the temperature of the generated cold water at the outlet cooled by the use side heat exchanger 5a on the upstream side of the water as the heat load medium is 10.2 to 10.3 when the intermediate temperature is 10.5 ° C. It will drop to ℃.

  Therefore, the intermediate temperature between the upstream refrigeration cycle R1 and the downstream refrigeration cycle R2 measured by the temperature sensor s1 is substantially the intermediate temperature so that the temperature of the cold water at the outlet of the downstream refrigeration cycle R2 is 7 ° C. Each frequency (rotational speed) of the compressor 1a of the upstream refrigeration cycle R1 and the compressor 1b of the downstream refrigeration cycle R2 is determined so as to be about 10.5 ° C. The compressors 1a and 1b may be fixed capacity compressors or variable capacity compressors.

  That is, the temperature of the heat medium between the upstream refrigeration cycle R1 and the downstream refrigeration cycle R2 is such that the temperature of the cold water at the outlet of the downstream refrigeration cycle R2 becomes a desired set temperature. The compressor 1a of the upstream refrigeration cycle R1 and the compressor of the downstream refrigeration cycle R2 so that the temperature of the heat load medium of the upstream refrigeration cycle R2 and the set temperature of the heat load medium at the outlet of the downstream refrigeration cycle R2 are substantially intermediate. Each frequency (rotational speed) with 1b is determined.

<Relationship Between Heat Load Medium and Refrigerant Temperature Upstream / Downstream of Use-side Heat Exchangers 5a and 5b in Heating Operation>
Next, the relationship between the upstream and downstream thermal load media and the refrigerant temperature in the heating operation shown in FIG. As described above, in FIG. 2B, the solid line arrows indicate the temperature of the refrigerant in the use side heat exchangers 5a and 5b, and the broken line arrows indicate the temperature of the heat load medium in the use side heat exchangers 5a and 5b. Show.

  In the case of the heating operation, the use side heat exchanger 5a of the upstream side refrigeration cycle R1 has a low temperature of hot water, so that the condensation temperature of the refrigerant is low. On the other hand, the use-side heat exchanger 5b of the downstream-side refrigeration cycle R2 has a higher hot water temperature than the upstream-use use-side heat exchanger 5a, so that the refrigerant condensing temperature becomes higher.

  Therefore, when the upstream and downstream compressors 6a and 6b have the same operation capacity, the upstream refrigeration cycle R1 has a lower condensation temperature than the downstream refrigeration cycle R2, and thus the high pressure decreases and the compressor 1a The power consumption becomes smaller. On the other hand, since the downstream refrigeration cycle R2 has a high condensation temperature, the high-pressure pressure rises and the power consumption of the compressor 1b increases. At this time, since the enthalpy difference on the evaporation side of the exhaust heat side heat exchangers 3a and 3b is proportional to the evaporation capacity, the exhaust heat heat of the upstream refrigeration cycle R1 is compared to the exhaust heat side heat exchanger 3b of the downstream refrigeration cycle R2. The exchanger 3a needs a capacity.

In the present embodiment, the operating capacity of the compressor 1b in the downstream refrigeration cycle R2 is made larger than the operating capacity of the compressor 1b in the upstream refrigeration cycle R1.
That is, in the case where the same heating capacity is provided in the upstream side refrigeration cycle R1 and the downstream side refrigeration cycle R2, the upstream side and downstream side compressors 1a and 1b have the same operating capacity as compared with the case where the upstream side refrigeration cycle R1 and the downstream side refrigeration cycle R2 have the same operating capacity The operating capacity of the compressor 1a is decreased, and the operating capacity of the downstream compressor 1b is increased.

  Since the upstream side refrigeration cycle R1 reduces the operating capacity of the compressor 1a, the capacity of the exhaust heat side heat exchanger 3a can be afforded, and the low pressure increases. On the other hand, since the downstream refrigeration cycle R2 increases the operating capacity of the compressor 1b, the low-pressure pressure is lowered, and the downstream heat exhaust side heat exchanger 3b has a large heat exchange capacity.

Moreover, the intermediate temperature of the heat load medium between the upstream refrigeration cycle R1 and the downstream refrigeration cycle R2 is decreased by increasing the operating capacity of the compressor 1b of the downstream refrigeration cycle R2. Therefore, the condensation temperature of the upstream refrigeration cycle R1 is lowered, and the efficiency is improved.
As a result, the heat exchange capacities of the upstream and downstream exhaust heat side heat exchangers 3a and 3b can be used efficiently.

  Therefore, the efficiency of the entire heat source unit (air conditioner C) increases the efficiency of the upstream refrigeration cycle R1 even if the operating capacity of the downstream compressor 1b, which is low in efficiency, is increased. Will rise.

  Here, the control device sets the temperature of the heat medium between the upstream refrigeration cycle R1 and the downstream refrigeration cycle R2 so that the temperature of the cold water at the outlet of the downstream refrigeration cycle R2 becomes a desired set temperature. The compressor 1a of the upstream refrigeration cycle R1 and the downstream refrigeration are set so that the temperature of the heat load medium at the inlet of the refrigeration cycle R1 is substantially intermediate between the temperature of the heat load medium at the outlet of the downstream refrigeration cycle R2. Each frequency (rotational speed) with the compressor 1b of cycle R2 is controlled.

  In the heating operation of FIG. 2 (b), the upstream side use side heat exchange 5a and the downstream side use side heat exchange 5b function as a refrigerant condenser that circulates in phase changes in the refrigeration cycles R1 and R2, respectively. . Therefore, the heat load medium is heated by the condensation heat of the refrigerant by passing through the upstream use side heat exchange 5a, and the temperature rises. Furthermore, the heat load medium that has passed through the pipe h1 is heated by the condensation heat of the refrigerant by passing through the downstream use side heat exchange 5b, so that the temperature rises and becomes a heat load medium at the set temperature. Be controlled.

  In FIG. 2B, the refrigerant on the upstream side promotes liquefaction by adjusting the expansion device 4a to lower the temperature in the vicinity of exiting the upstream use side heat exchange 5a. Similarly, the downstream refrigerant adjusts the expansion device 4b to decrease the temperature in the vicinity of exiting the downstream use side heat exchange 5b, and promotes liquefaction.

The cooling operation or heating operation described above is performed so that the upstream exhaust heat side heat exchanger 3a and the downstream exhaust heat side heat exchanger 3b perform heat exchange with the same or nearly equivalent heat exchange capacity. I have control.
The fact that the upstream exhaust heat side heat exchanger 3a and the downstream exhaust heat side heat exchanger 3b perform heat exchange with the same or similar heat exchange capacity means that the upstream compressor 1a The pressure value on the high pressure side detected by the pressure sensor s4 provided on the outlet side of the compressor is equal to or equivalent to the pressure value on the high pressure side detected by the pressure sensor s5 provided on the outlet side of the downstream compressor 1b. It becomes clear (detected) from near.

According to the above configuration, the operating capacity of the compressor 1b of the downstream refrigeration cycle R2 is made larger than the operating capacity of the compressor 1a of the upstream refrigeration cycle R1, so that the heat source machine (air conditioning) can be used during both the cooling operation and the heating operation. Machine C) The overall efficiency can be improved.
Also, the temperature of the heat load medium at the outlet of the downstream use side heat exchanger 3b and the temperature of the heat load medium between the downstream use side heat exchanger 3b and the upstream use side heat exchanger 3a. Since the difference from the intermediate temperature is made substantially the same as the difference between the intermediate temperature and the temperature of the heat load medium at the inlet of the upstream use side heat exchanger 3a, the efficiency of the entire heat source apparatus can be improved.

  Further, since the exhaust heat side heat exchangers 3a and 3b of the upstream and downstream refrigeration cycles R1 and R2 perform equivalent or nearly equivalent heat exchange, the efficiency of the entire heat source apparatus can be improved.

  Further, the exhaust heat side heat exchangers 3a and 3b of the upstream and downstream refrigeration cycles R1 and R2 perform equivalent or nearly equivalent heat exchange, so that the exhaust heat side heat of the upstream and downstream refrigeration cycles R1 and R2 The capacity of the exchangers 3a and 3b can be used up in a balanced manner. Therefore, the smallest heat exchanger having the necessary heat exchange capacity can be selected as the exhaust heat side heat exchangers 3a and 3b. Further, the exhaust heat side heat exchangers 3a and 3b of the upstream and downstream refrigeration cycles R1 and R2 can have the same capacity, and the same heat exchanger can be used.

  Therefore, the production cost can be reduced due to the mass production effect of using the heat exchangers of the same capacity as the exhaust heat side heat exchangers 3a and 3b. In addition, since the same heat exchanger can be used for the exhaust heat side heat exchangers 3a and 3b, the layout is good.

Further, the product dimensions of the air conditioner C can be reduced.
Moreover, the cost reduction by the optimal capacity | capacitance of the waste heat side heat exchanger 3a, 3b is possible. By using the same components for the exhaust heat side heat exchangers 3a and 3b, the management cost can be reduced.

<< Embodiment 2 >>
FIG. 3 is a refrigeration cycle diagram of an air conditioner according to Embodiment 2 of the present invention.
The air conditioner 2C of the second embodiment is obtained by changing the compressor 1b of the downstream refrigeration cycle R2 of the first embodiment of FIG. 1 to a multi-cycle configuration in which two compressors 1d and 1e are connected in parallel. .
Since other components are the same as those in the first embodiment, the same components are denoted by the same reference numerals and the description thereof is omitted.

In the air conditioner 2C of the second embodiment, the operating capacity of the compressor 1a in the upstream refrigeration cycle R21 is made larger than the total operating capacity of the compressors 1d and 1e in the downstream refrigeration cycle R22.
The states of the upstream and downstream refrigeration cycles R21 and R22 during the cooling operation and heating operation of the air conditioner 2C are the same as those described in the first embodiment.

  Specifically, in the air conditioner 2C, during the cooling operation, the control device controls the upstream side so that the temperature of the heat load medium at the outlet of the use side heat exchange 5b of the downstream side refrigeration cycle R22 becomes a desired set temperature. The temperature of the heat load medium between the refrigeration cycle R21 and the downstream refrigeration cycle R22 is such that the temperature of the heat load medium at the inlet of the use side heat exchange 5a of the upstream refrigeration cycle R21 and the use side heat exchange of the downstream refrigeration cycle R22. Each frequency (rotational speed) of the upstream side compressor 1a and the downstream side compressor 1b is controlled so as to be a temperature substantially in the middle of the set temperature of the heat load medium at the outlet 5b. In other words, during the cooling operation, the operating capacity of the compressor 1b in the downstream refrigeration cycle R22 is larger than the operating capacity of the compressor 1a in the upstream refrigeration cycle R21.

  On the other hand, during the heating operation, the upstream refrigeration cycle R21 and the downstream refrigeration cycle R22 are controlled by the control device so that the temperature of the heat load medium at the outlet of the use side heat exchange 5b of the downstream refrigeration cycle R22 becomes a desired set temperature. The temperature of the heat load medium between the refrigeration cycle and the heat load medium at the inlet of the utilization side heat exchange 5a of the upstream refrigeration cycle R21 and the heat load medium at the outlet of the utilization side heat exchange 5b of the downstream refrigeration cycle R22 are set. Each frequency (rotational speed) of the upstream side compressor 1a and the downstream side compressor 1b is controlled so that the temperature is substantially in the middle of the temperature. In other words, during the heating operation, the operating capacity of the compressor 1b in the downstream refrigeration cycle R22 is larger than the operating capacity of the compressor 1a in the upstream refrigeration cycle R21.

  Alternatively, in the cooling operation or the heating operation, heat exchange is performed between the upstream exhaust heat side heat exchanger 3a and the downstream exhaust heat side heat exchanger 3b with heat exchange capacities that are equivalent or close to equivalent. Be controlled. The fact that the upstream exhaust heat side heat exchanger 3a and the downstream exhaust heat side heat exchanger 3b perform heat exchange with the same or similar heat exchange capacity means that the outlet of the upstream compressor 1a Obviously, the high pressure value measured by the pressure sensor s4 on the side and the high pressure value measured by the pressure sensor s5 on the outlet side of the downstream compressors 1d and 1e are equal or close to equivalent values. Become (detected).

  According to the above configuration, since the total operating capacity of the compressors 1d and 1e of the downstream refrigeration cycle R22 is made larger than the operating capacity of the compressor 1a of the upstream refrigeration cycle R21, the entire air conditioner 3C of the heat source machine Increases efficiency.

  Further, during the cooling operation and the heating operation, the temperature of the heat load medium between the upstream refrigeration cycle R21 and the downstream refrigeration cycle R22 is the same as the temperature of the heat load medium at the inlet of the upstream refrigeration cycle R21 and the downstream refrigeration cycle. Since the temperature is controlled so as to be approximately intermediate to the set temperature of the heat load medium at the outlet of R22, the efficiency of the entire air conditioner 3C of the heat source device is improved.

  Further, by making the heat exchange capacities of the upstream and downstream exhaust heat side heat exchangers 3a and 3b equivalent or close to each other, heat exchange between the upstream and downstream exhaust heat side heat exchangers 3a and 3b is achieved. The capacity can be used up in a well-balanced manner. Therefore, the upstream and downstream exhaust heat side heat exchangers 3a and 3b can have the same or similar heat exchange capacity, and the same heat exchanger can be used.

  Therefore, it is possible to reduce the size of the exhaust heat side heat exchangers 3a and 3b by optimizing the capacity, and to reduce the product size of the air conditioner 2C. Moreover, the cost reduction by the optimal capacity | capacitance of the waste heat side heat exchanger 3a, 3b is possible.

  Furthermore, the management cost can be reduced by adopting the same components for the exhaust heat side heat exchangers 3a and 3b. In addition, since the same heat exchanger can be used for the exhaust heat side heat exchangers 3a and 3b, the layout is good.

  The upstream compressor 1 may be a compressor capable of changing the operating capacity, one of the downstream compressors 1d and 1e may be a compressor capable of changing the operating capacity, and the other may be a compressor having a fixed operating capacity. . Thereby, the operating capacity of the downstream compressors 1d and 1e can be easily made larger than the operating capacity of the upstream compressor 1 under various conditions. Further, since one of the downstream side compressors 1d and 1e is a fixed compressor, the cost can be reduced.

<< Embodiment 3 >>
FIG. 4 is a refrigeration cycle diagram of an air conditioner according to Embodiment 3 of the present invention.
The air conditioner 3C according to the third embodiment is a utilization side heat exchanger 5a, 5b of the air conditioner C according to the first embodiment shown in FIG. The side heat exchangers 5d and 5e are changed.

That is, the air conditioner 3C uses the upstream refrigeration cycle R31 as two refrigeration cycles R31A and R31B, and uses two heat exchange channels for the refrigerant in the upstream use side heat exchanger 5d. At the same time, the downstream side refrigeration cycle R32 is set to two refrigeration cycles R32A and R32B, and the refrigerant heat exchange channel of the downstream side use side heat exchanger 5e is set to two channels.
The configuration of each refrigeration cycle R31A, R31B, R32A, R32B is the same as that of the first embodiment, and the same components are denoted by the same reference numerals and the description thereof is omitted.

  In the air conditioner 3C of the third embodiment, the two upstream refrigeration cycles R31A and R31B connected to the upstream use side heat exchanger 5d operate each compressor 1a with the same capacity. The two downstream refrigeration cycles R32A and R32B connected to the downstream use side heat exchanger 5e also operate the compressors 1b with the same capacity.

Then, the operating capacities of the compressors 1b of the two downstream refrigeration cycles R32A and R32B are made larger than the operating capacities of the compressors 1a of the two upstream refrigeration cycles R31A and R31B.
The states of the upstream and downstream refrigeration cycles R31 and R32 during the cooling operation and the heating operation are the same as those of the refrigeration cycles R1 and R2 described in the first embodiment.

  Specifically, in the air conditioner 3C, during the cooling operation, the control device controls the upstream side so that the temperature of the heat load medium at the outlet of the use side heat exchanger 5e of the downstream side refrigeration cycle R32 becomes a desired set temperature. The temperature of the heat load medium between the side refrigeration cycle R31 and the downstream refrigeration cycle R32 is the temperature of the heat load medium at the inlet of the upstream refrigeration cycle R31 and the set temperature of the heat load medium at the outlet of the downstream refrigeration cycle R32. Each frequency (rotational speed) of the compressor 1a of the upstream refrigeration cycle R31 and the compressor 1b of the downstream refrigeration cycle R2 is controlled so that the temperature becomes substantially intermediate.

  On the other hand, during the heating operation, the upstream refrigeration cycle R31 and the downstream refrigeration cycle are controlled by the control device so that the temperature of the heat load medium at the outlet of the use side heat exchanger 5e of the downstream refrigeration cycle R32 becomes a desired set temperature. The temperature of the heat load medium between R32 and R32 should be approximately intermediate between the temperature of the heat load medium at the inlet of the upstream refrigeration cycle R31 and the set temperature of the heat load medium at the outlet of the downstream refrigeration cycle R32. Each frequency (rotational speed) of the compressor 1a on the side and the compressor 1b on the downstream side is controlled.

  Alternatively, in the cooling operation or the heating operation, the heat exhaust side heat exchanger 3a on the upstream side and the heat exhaust side heat exchanger 3b on the downstream side perform heat exchange with the same or nearly equivalent heat exchange capacity. Be controlled. This is the sum of the pressure values on the outlet side of the upstream compressor 1a (upstream high pressure) and the sum of the pressure values on the outlet side of the downstream compressor 1b (downstream high pressure). Becomes apparent (detected) by becoming equivalent or close to the equivalent.

According to the above configuration, since the total operation capacity of the downstream compressor 1b is larger than the total operation capacity of the upstream compressor 1a, the efficiency of the entire air conditioner 3C as a heat source apparatus can be improved.
Further, since the heat exchange is performed with the heat exchange capacities of the exhaust heat side heat exchanger capacities 3a and 3b that are equal to or close to the same, the exhaust heat side heat exchanger capacities 3a and 3b can be used up in a well-balanced manner. As a result, the exhaust heat side heat exchangers 3a and 3b of the upstream and downstream refrigeration cycles R31 and R32 can have the same capacity or close to the same capacity, and the exhaust heat side heat exchangers 3a and 3b can be replaced with the same heat exchanger. Can be used.
Therefore, the product dimensions of the air conditioner 3C can be reduced.

  And cost reduction by the optimal capacity | capacitance of the waste heat side heat exchanger 3a, 3b can be aimed at. Moreover, the management expense by employ | adopting the same component for the waste heat side heat exchangers 3a and 3b can be reduced. In addition, since the same heat exchanger can be used for the exhaust heat side heat exchangers 3a and 3b, the layout is good.

  In the third embodiment, the number of compressors 1a and 1b in each refrigeration cycle R31A, R31B, R32A, and R32B is one, but as in the second embodiment, each refrigeration cycle R31A, R31B, R32A, and R32B The number of any one of the compressors 1a and 1b may be plural.

  In the third embodiment, the upstream use side heat exchanger 5d and the downstream use side heat exchanger 5e exchange heat with two refrigeration cycles R31A and R31B and two refrigeration cycles R32A and R32B, respectively. However, the heat exchange may be performed by three or more refrigeration cycles.

  Alternatively, as in the air conditioner 3C1 illustrated in FIG. 5, the downstream refrigeration cycles R32A and R32B may have two compressors 1d and 1e, respectively. Thereby, the capacity | capacitance of a downstream compressor can be easily controlled larger than the capacity | capacitance of an upstream compressor. FIG. 5 is a refrigeration cycle diagram of an example of an air conditioner according to the third embodiment.

<< Embodiment 4 >>
FIG. 6 is a refrigeration cycle diagram of an air conditioner according to Embodiment 4 of the present invention.
The air conditioner 4C according to the fourth embodiment is different from the first embodiment shown in FIG. 1 in that the upstream side refrigeration cycle R41, the middle flow side refrigeration cycle R42, the downstream side refrigeration cycle R43 and the flow path of the heat load medium of the three refrigeration cycles. The pipes h41a and h41b are connected in series.
The configurations of the upstream refrigeration cycle R41 and the downstream refrigeration cycle R43 are the same as those in the first embodiment, and the same components are denoted by the same reference numerals and description thereof is omitted.

  In the middle flow side refrigeration cycle R42, a compressor 1c, a four-way valve 2c, an exhaust heat side heat exchanger 3c, an expansion device 4c, a use side heat exchanger 5c, and an accumulator 6c are connected by a pipe h46. The operation of the midstream refrigeration cycle R42 is the same as that of the upstream and downstream refrigeration cycles R41 and R43. A pressure sensor s6 is provided on the outlet side of the midstream compressor 1c, and the high pressure of the midstream refrigeration cycle R42 is measured.

The intermediate-stream-side exhaust heat-side heat exchanger 3c, the upstream-side exhaust heat-side heat exchanger 3a, and the downstream-side exhaust heat-side heat exchanger 3b have heat exchange capacities that are equivalent or close to equivalent. Is used.
The exhaust heat side heat exchangers 3a, 3c, and 3b of the upstream, middle, and downstream refrigeration cycles R41, R42, and R43 have equivalent or nearly equivalent heat exchange capacities.
And the operating capacity of the compressor 1b of the downstream refrigeration cycle R43 is made larger than the operating capacity of the compressor 1c of the midstream refrigeration cycle R42. In addition, the operating capacity of the compressor 1c of the midstream refrigeration cycle R42 is made larger than the operating capacity of the compressor 1a of the upstream refrigeration cycle R41.
The states of the refrigeration cycles R41, R42, and R43 during the cooling operation and the heating operation are the same as those of the refrigeration cycles R1 and R2 described in the first embodiment.

Specifically, in the air conditioner 4C, during the cooling operation and the heating operation, the temperature of the heat load medium at the outlet of the use side heat exchanger 5b of the downstream refrigeration cycle R43 becomes a desired set temperature by the control device. Control is performed as follows.
Temperature sensors s41, s42, s43, and s44 for measuring the temperature of the thermal load medium are provided in the pipes h42, h41a, h41b, and h43, respectively.

  During the cooling operation and the heating operation, the operating capacity of the compressor 1b in the downstream refrigeration cycle R43 is larger than the operating capacity of the compressor 1c in the midstream refrigeration cycle R42, and the operating capacity of the compressor 1c in the midstream refrigeration cycle R42. However, it becomes larger than the operating capacity of the compressor 1a of the upstream refrigeration cycle R41.

  Alternatively, during the cooling operation and the heating operation, the temperature difference between the inlet and outlet heat load media of the upstream side refrigeration cycle R41 and the inlet side of the usage side heat exchanger 5b of the midstream side refrigeration cycle R42. Compressors 1a and 1b so that the difference between the temperature of the heat load medium at the outlet and the temperature of the heat load medium at the outlet and the difference between the temperatures of the heat load medium at the outlet and the heat exchanger 5b in the downstream side refrigeration cycle R43 are substantially the same. 1c is controlled.

  Alternatively, in the cooling operation or the heating operation, the upstream side exhaust heat side heat exchanger 3a, the midstream side exhaust heat side heat exchanger 3c, and the downstream side exhaust heat side heat exchanger 3b are equivalent or equivalent. It is controlled so that heat exchange is performed with a near heat exchange capacity. This is because the detected pressure value of the upstream pressure sensor s4 (upstream high pressure), the detected pressure value of the downstream pressure sensor s5 (downstream high pressure), and the detected pressure of the midstream pressure sensor s6. It is clarified (detected) that the value (high pressure on the middle stream side) is equivalent or nearly equivalent.

  According to the above configuration, since the operating capacities of the compressors 1a, 1c, and 1b increase from the upstream refrigeration cycle R41 to the downstream refrigeration cycle R43, the efficiency of the entire air conditioner 4C of the heat source unit can be improved.

Further, the heat exhaust side heat exchanger 3a on the upstream side, the heat exhaust side heat exchanger 3c on the middle stream side, and the heat exhaust side heat exchanger 3b on the downstream side exchange heat with an equivalent or nearly equivalent heat exchange capacity. Therefore, the heat exchange capacities of the upstream, middle stream, and downstream exhaust heat side heat exchangers 3a, 3c, and 3b can be used in a well-balanced manner. Therefore, the exhaust heat side heat exchangers 3a, 3b, and 3c of the upstream, middle stream, and downstream refrigeration cycles R41, R42, and R43 can have the same heat exchange capacity or a heat exchange capacity close to equivalent. Therefore, the same heat exchanger can be used for the exhaust heat side heat exchangers 3a, 3c, and 3b.
Therefore, the product size of the air conditioner 4C can be reduced.

  Further, cost reduction can be achieved by optimizing the capacity of the exhaust heat side heat exchangers 3a, 3b, and 3c. Further, since the exhaust heat side heat exchangers 3a, 3b, 3c can employ the same parts, the management cost can be reduced. In addition, since the same heat exchanger can be used for the exhaust heat side heat exchangers 3a, 3b, and 3c, the layout is good.

  In the fourth embodiment, the number of the compressors 1a, 1c, and 1b in each refrigeration cycle R41, R42, and R43 is one, but the compressor 1a in each refrigeration cycle R41, R42, and R43 as in the second embodiment. A plurality of at least one of 1c and 1b may be used. Moreover, although the flow path of the heat load medium is connected in series by the three refrigeration cycles R41, R42, and R43, four or more refrigeration cycles may be connected in series.

<< Other Embodiments >>
1. The exhaust heat side heat exchanger having the same or nearly equivalent heat exchange capacity described in the claims includes a heat exchanger in which one to several passes of the same exhaust heat side heat exchanger are eliminated. Shall.

2. Although various configurations have been described, these configurations may be appropriately selected and combined.

3. The present invention is not limited to the embodiments described above, and includes various embodiments. For example, the above-described embodiment is a description of the present invention in an easy-to-understand manner, and is not necessarily limited to one having all the configurations described. For example, a part of the configuration described may be included.

4). In addition, the present invention naturally includes various specific forms other than the above-described embodiments within the scope of the claims.

1a, 1b, 1c, 1d, 1e Compressor 2a, 2b, 2c Four-way valve 3a, 3b, 3c Waste heat side heat exchanger 4a, 4b, 4c Expansion device 5a, 5b, 5c, 5d, 5e Use side heat exchanger C, 2C, 3C, 3C1, 4C Air conditioner h4, h5 Piping (refrigerant piping)
R1, R21, R31, R31A, R31B, R41 Upstream refrigeration cycle (upstream refrigeration equipment)
R2, R22, R32, R32A, R32B, R43 Downstream refrigeration cycle (downstream refrigeration equipment)
R42 Refrigeration cycle (midstream refrigeration equipment)

Claims (11)

An upstream refrigeration system in which a compressor, a four-way valve, an exhaust heat side heat exchanger, an expansion device, and a use side heat exchanger are connected by refrigerant piping;
A compressor, a four-way valve, an exhaust heat side heat exchanger, an expansion device, and a downstream side refrigeration device to which a use side heat exchanger is connected by a refrigerant pipe;
The flow path of the heat load medium of the use side heat exchanger is connected in series in the order of the upstream refrigeration apparatus and the downstream refrigeration apparatus,
The exhaust heat side heat exchanger of the upstream refrigeration apparatus and the exhaust heat side heat exchanger of the downstream refrigeration apparatus have an equivalent or nearly equivalent heat exchange capacity,
The air conditioner characterized in that the operating capacity of the compressor on the downstream side is larger than the operating capacity of the compressor on the upstream side. An upstream refrigeration system in which a compressor, a four-way valve, an exhaust heat side heat exchanger, an expansion device, and a use side heat exchanger are connected by refrigerant piping;
A compressor, a four-way valve, an exhaust heat side heat exchanger, an expansion device, and a downstream side refrigeration device to which a use side heat exchanger is connected by a refrigerant pipe;
The flow path of the heat load medium of the use side heat exchanger is connected in series in the order of the upstream refrigeration apparatus and the downstream refrigeration apparatus,
The exhaust heat side heat exchanger of the upstream refrigeration apparatus and the exhaust heat side heat exchanger of the downstream refrigeration apparatus have an equivalent or nearly equivalent heat exchange capacity,
The temperature of the heat load medium at the outlet of the downstream use side heat exchanger and the intermediate temperature that is the temperature of the heat load medium between the downstream use side heat exchanger and the upstream use side heat exchanger The air conditioner is characterized by being substantially the same as the difference between the intermediate temperature and the temperature of the heat load medium at the inlet of the upstream use side heat exchanger. In the air conditioner according to claim 1 or 2,
The air conditioner is characterized in that heat exchange equivalent to or close to equivalent is performed between the exhaust heat side heat exchanger of the upstream refrigeration apparatus and the exhaust heat side heat exchanger of the downstream refrigeration apparatus. In the air conditioner according to claim 1 or 2,
The compressor of the said downstream refrigeration apparatus is a some compressor. The air conditioner characterized by the above-mentioned. In the air conditioner according to claim 1 or 2,
The compressor of the downstream refrigeration apparatus is a plurality of compressors,
The compressor of the upstream refrigeration apparatus is a compressor capable of varying an operating capacity,
The plurality of compressors of the downstream-side refrigeration apparatus are a compressor capable of changing an operating capacity and a compressor having a fixed operating capacity. In the air conditioner according to claim 1,
The upstream use side heat exchanger and the downstream use side heat exchanger are heat exchangers capable of exchanging heat with the thermal load medium and a plurality of refrigeration cycles, respectively.
The total operating capacity of the compressor on the downstream side is greater than the total operating capacity of the compressor on the upstream side. A compressor, a four-way valve, an exhaust heat side heat exchanger, an expansion device, and a use side heat exchanger are provided with a plurality of refrigeration devices connected by refrigerant piping,
The flow path of the heat load medium of the use side heat exchanger of each refrigeration apparatus is connected in series in order,
The exhaust heat side heat exchanger of each refrigeration apparatus has an equivalent or nearly equivalent heat exchange capacity,
The air conditioner characterized in that the operating capacity of the compressor of each refrigeration apparatus increases from the upstream side to the downstream side. The air conditioner according to claim 7,
The air conditioner characterized in that the difference in temperature of the heat load medium at the inlet and outlet of each use side heat exchanger is substantially the same. The air conditioner according to claim 7,
Each of the exhaust heat side heat exchangers of the plurality of refrigeration apparatuses performs equivalent or nearly equivalent heat exchange. The air conditioner according to claim 1 or claim 2 or claim 7,
The air conditioner is characterized in that the same heat exchanger is used as the use side heat exchanger. The air conditioner according to claim 1 or claim 2 or claim 7,
The air conditioner characterized in that the high-pressure pressure of each of the refrigeration apparatuses has substantially the same pressure value.

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