CN101666559A - Refrigerating and air-conditioning plant - Google Patents

Abstract

The object of the present invention is to obtain a refrigerating and air-conditioning system that has a higher heating capacity than conventional gas injection cycles and can fully exert its heating capacity even in cold regions where the outside air is below minus 10°C. The refrigerating and air-conditioning unit connects the compressor (3), the indoor heat exchanger (6), the first decompression device (11), and the outdoor heat exchanger (12) in a ring shape, and provides heating from the indoor heat exchanger, and has the function of The refrigerant between the indoor heat exchanger and the first decompression device and the first internal heat exchanger (9) for heat exchange between the refrigerant between the outdoor heat exchanger and the compressor, and the indoor heat exchanger and the first Part of the refrigerant between the decompression devices is divided and injected into the injection circuit (13) of the compression chamber in the compressor, the decompression device (14) for injection installed on the injection circuit, and the pressure reducing device (14) for injection that has passed through the decompression device. A second internal heat exchanger (10) for exchanging heat between the refrigerant decompressed by the decompression device and the refrigerant between the indoor heat exchanger and the first decompression device.

Description

Refrigeration and air conditioning unit

This divisional application is based on the divisional application of the Chinese patent application with the application number 200680000916.0 and the application date of March 27, 2006, and the invention title is "refrigeration and air conditioning device".

technical field

The present invention relates to a refrigerating and air-conditioning device, in particular to a refrigerating and air-conditioning device that performs gas injection to increase the heating capacity when the outside air temperature is low.

Background technique

In the existing refrigerating and air-conditioning equipment, a gas-liquid separator is installed in the intermediate pressure part between the condenser and the evaporator, and the gas refrigerant separated by the gas-liquid separator is sprayed to the intermediate pressure part of the compressor, thereby improving the heating capacity (For example, refer to Patent Document 1).

In addition, there is also a refrigerating and air-conditioning device that divides a part of the high-pressure liquid refrigerant, decompresses it, exchanges heat with the high-pressure liquid refrigerant, evaporates it into gas, and sprays it into the compressor to improve the heating capacity. Liquid separator (for example, refer to Patent Document 2).

In addition, there is also a device in which a liquid accumulator is provided in the intermediate pressure portion between the condenser and the evaporator, and the refrigerant in the liquid accumulator and the refrigerant sucked by the compressor perform heat exchange (for example, refer to Patent Document 3).

Patent Document 1: Japanese Patent Laid-Open No. 2001-304714

Patent Document 2: Japanese Patent Laid-Open No. 2000-274859

Patent Document 3: Japanese Patent Laid-Open No. 2001-174091

Contents of the invention

However, the conventional refrigerating and air-conditioning apparatus has the following problems.

First, in the case of performing injection with a gas-liquid separator as in the conventional example described in Patent Document 1, the liquid amount in the gas-liquid separator changes according to the injection amount, and the distribution of the liquid refrigerant amount in the refrigeration cycle varies with the The change has the problem of unstable operation.

When the injected gas refrigerant flow and the gas refrigerant flow in the two-phase refrigerant flowing into the gas-liquid separator are balanced, only the liquid refrigerant flows out to the evaporator side, although the amount of liquid refrigerant in the gas-liquid separator Stable, but the injected refrigerant flow is reduced. If the flow rate of the refrigerant is less than the flow rate of the gas refrigerant flowing into the gas-liquid separator, the operation in which the gas refrigerant also flows out to the evaporator side is formed, and the gas flows out from the bottom of the gas-liquid separator, thus forming liquid in the gas-liquid separator Almost all out of the running.

On the contrary, if the injected refrigerant flow rate increases, the gas refrigerant will be insufficient, so the liquid refrigerant will be mixed into the gas refrigerant and injected, and the liquid will flow out from the top of the gas-liquid separator, so the liquid in the gas-liquid separator is almost is full.

Since the injection flow rate is likely to change according to the high and low pressure of the refrigeration cycle, the pressure of the gas-liquid separator, and the operating capacity of the compressor, the injection flow rate is hardly in balance with the flow rate of the gas refrigerant flowing into the gas-liquid separator. The amount of liquid refrigerant in the gas-liquid separator is almost zero or full, and the amount of refrigerant in the gas-liquid separator tends to change depending on the operating conditions. As a result, the refrigerant quantity distribution in the refrigeration cycle changes, and unstable operation tends to occur.

As in the conventional example described in Patent Document 2, if a part of the high-pressure liquid refrigerant is divided and sprayed, since there is no liquid storage part, it can solve the problem of changing the amount of refrigerant in such a gas-liquid separator. Instability due to changes. However, such a form also has the following problems.

In general, in a refrigeration cycle in which gas injection is performed, the injection flow rate is increased to increase the heating capacity as the flow rate of the refrigerant discharged from the compressor and flowing into the indoor heat exchanger increases.

However, once the injection flow rate is increased, the liquid refrigerant is also mixed with the gas refrigerant for injection, and the heat exchange capacity of the indoor heat exchanger decreases due to the decrease in the discharge temperature of the compressor and the decrease in the temperature of the refrigerant at the inlet of the indoor heat exchanger. Therefore, there is an injection flow rate that achieves the maximum heating capacity by maintaining a balance between the refrigerant flow rate and the heat exchange capacity.

In general air heat source heat pump refrigerating and air-conditioning equipment, in cold regions where the outside air is below minus 10°C, the heating capacity is reduced and sufficient heating operation cannot be performed. Therefore, a device that can exert more heating capacity is required. However, in the gas injection cycle described above, since the heating capacity has a limit, there is a problem that a sufficient heating operation cannot be performed.

Also, in the conventional example described in Patent Document 3, the circuit structure does not contribute to increasing the heating capacity, and similarly, there is a problem that the heating capacity decreases in cold regions, and sufficient heating operation cannot be performed.

In view of the above-mentioned problems, the object of the present invention is to obtain a refrigerating and air-conditioning apparatus that has a higher heating capacity than conventional gas injection cycles and can fully exert its heating capacity even in cold regions where the outside air is below minus 10°C.

The refrigerating and air-conditioning apparatus of the present invention connects the compressor, the indoor heat exchanger, the first decompression device, and the outdoor heat exchanger in a ring shape, supplies heat from the above-mentioned indoor heat exchanger, and has The first internal heat exchanger for exchanging heat between the refrigerant between the devices and the refrigerant between the outdoor heat exchanger and the compressor, and the refrigerant between the indoor heat exchanger and the first decompression device The injection circuit that splits a part of the flow and injects it into the compression chamber in the compressor, the decompression device for injection installed on the injection circuit, and the refrigerant decompressed by the decompression device for injection and the indoor heat The second internal heat exchanger for exchanging heat with the refrigerant between the exchanger and the above-mentioned first pressure reducing device.

According to the present invention as described above, when the compressor, the indoor heat exchanger, the first decompression device, and the outdoor heat exchanger are connected in a loop to perform a heating operation in which heating is performed from the indoor heat exchanger, by using the The refrigerant between the indoor heat exchanger and the first decompression device and the first internal heat exchanger for heat exchange between the refrigerant between the outdoor heat exchanger and the compressor heat the refrigerant sucked by the compressor, even if the indoor Part of the refrigerant between the heat exchanger and the first decompression device is divided to increase the flow rate of the refrigerant injected into the compression chamber in the compressor, which can also suppress the decrease in the discharge temperature of the compressor. In the indoor heat exchanger By exhibiting sufficient heat exchange performance, sufficient heating capacity can be ensured even under conditions where the heating capacity is likely to decrease due to low outside air conditions, etc. The second internal heat exchanger that exchanges heat with the refrigerant between the indoor heat exchanger and the first decompression device, when supplying the refrigerant for gas injection, passes through the refrigerant that will be split without relying on the gas-liquid separator The gasification supply has the effect of avoiding the change of the liquid amount caused by the use of the gas-liquid separator, and realizing a more stable operation of the device.

Description of drawings

Fig. 1 is a refrigerant circuit diagram showing a refrigerating and air-conditioning apparatus according to a first embodiment of the present invention.

Fig. 2 is a PH diagram showing the operation status when the refrigerating and air-conditioning apparatus performs heating operation.

Fig. 3 is a pH diagram showing the operation status of the refrigerating and air-conditioning apparatus in cooling operation.

Fig. 4 is a flowchart showing a control operation when the refrigerating and air-conditioning apparatus performs a heating operation.

Fig. 5 is a flowchart showing control operations when the refrigerating and air-conditioning apparatus performs cooling operation.

Fig. 6 is a pH diagram showing the operation status of the refrigerating and air-conditioning apparatus when gas injection is performed.

Fig. 7 is a graph showing changes in the temperature of the condenser when the refrigerating and air-conditioning apparatus performs gas injection.

Fig. 8 is a graph showing the operating characteristics of the refrigerating and air-conditioning apparatus when the gas injection flow rate is changed.

Fig. 9 is a graph showing different operating characteristics depending on whether or not the refrigerating and air-conditioning apparatus has a first internal heat exchanger.

Fig. 10 is another graph showing the operating characteristics of the refrigerating and air-conditioning apparatus when the gas injection flow rate is changed.

Fig. 11 is a refrigerant circuit diagram showing a refrigerating and air-conditioning apparatus according to a second embodiment of the present invention.

Detailed ways

first embodiment

Fig. 1 is a refrigerant circuit diagram showing a refrigerating and air-conditioning apparatus according to a first embodiment of the present invention.

In Fig. 1, a compressor 3, a four-way valve 4 for switching between heating and cooling operations, an outdoor heat exchanger 12, a first expansion valve 11 as a decompression device, and a second internal heat exchanger are installed in an outdoor unit 1. An exchanger 10, a first internal heat exchanger 9, a second expansion valve 8 as a decompression device, an injection circuit 13, and a third expansion valve 14 as a decompression device for injection.

The compressor 3 is of a type in which the rotation speed is controlled by an inverter and the capacity is controlled, and the refrigerant supplied from the injection circuit 13 can be injected into the compression chamber in the compressor 3 .

Furthermore, the first expansion valve 11 , the second expansion valve 8 , and the third expansion valve 14 are electronic expansion valves whose openings are variably controlled. In addition, the outdoor heat exchanger 12 exchanges heat with outside air blown by a blower or the like.

The indoor heat exchanger 6 is installed in the indoor unit 2 . The gas pipe 5 and the liquid pipe 7 are connecting pipes connecting the outdoor unit 1 and the indoor unit 2 . As a refrigerant for this refrigerating and air-conditioning apparatus, R410A, which is an HFC-based mixed refrigerant, is used.

A measurement control device 15 and temperature sensors 16 are provided in the outdoor unit 1 . The temperature sensor 16a is installed on the discharge side of the compressor 3, the temperature sensor 16b is installed between the outdoor heat exchanger 12 and the four-way valve 4, and the temperature sensor 16c is installed on the refrigerant flow path in the middle of the outdoor heat exchanger 12. The sensor 16d is provided between the outdoor heat exchanger 12 and the first expansion valve 11, the temperature sensor 16e is provided between the first internal heat exchanger 9 and the second expansion valve 8, and the temperature sensor 16f is provided on the suction side of the compressor 3. , respectively measure the refrigerant temperature at the setting position. Furthermore, the temperature sensor 16g measures the temperature of the outside air around the outdoor unit 1 .

The temperature sensors 16h, 16i, and 16j are installed in the indoor unit 2, the temperature sensor 16h is installed on the refrigerant flow path in the middle of the indoor heat exchanger 6, and the temperature sensor 16i is installed between the indoor exchanger 6 and the liquid pipe 7, respectively. Measure the refrigerant temperature at the installation location. The temperature sensor 16j measures the temperature of the air sucked into the indoor heat exchanger 6 . Moreover, when the heat medium used as a load is another medium, such as water, the temperature sensor 16j measures the inflow temperature of the said medium.

The temperature sensors 16c and 16h can detect high and low pressure refrigerant saturation temperatures by detecting the temperature of the refrigerant in a gas-liquid two-phase state in the middle of each heat exchanger.

In addition, the measurement control device 15 in the outdoor unit 1 controls the operation method of the compressor 3, the flow path conversion of the four-way valve 4, and the outdoor heat exchange according to the measurement information of the temperature sensor 16 and the operation content instructed by the user of the refrigeration and air-conditioning apparatus. The air supply volume of the blower of the device 12 and the opening of each expansion valve, etc.

The operation of this refrigerating and air-conditioning apparatus will be described below.

First, the operation during the heating operation will be described based on the pH diagram during the heating operation shown in FIGS. 1 and 2 .

During the heating operation, the flow path of the four-way valve 4 is set in the direction of the solid line in FIG. 1 . The high-temperature and high-pressure gas refrigerant (point 1 in FIG. 2 ) discharged from the compressor 3 flows into the outdoor unit 1 through the four-way valve 4 and flows into the indoor unit 2 through the gas pipe 5 . Then, it flows into the indoor heat exchanger 6, and condenses and liquefies while dissipating heat in the indoor heat exchanger 6 serving as a condenser to become a high-pressure, low-temperature liquid refrigerant (point 2 in FIG. 2 ). Heating is performed by supplying the heat released from the refrigerant to load-side media such as air and water on the load side.

After the high-pressure and low-temperature refrigerant flowing out of the indoor heat exchanger 6 flows into the outdoor unit 1 through the liquid pipe 7, after some decompression in the second expansion valve 8 (point 3 in Figure 2), the first internal heat exchange The low-temperature refrigerant drawn into the compressor 3 is cooled by supplying heat to the compressor 9 (point 4 in FIG. 2 ).

Then, after part of the refrigerant is branched to the injection circuit 13, in the second internal heat exchanger 10, heat is exchanged with the refrigerant that is branched to the injection circuit 13 and decompressed in the third expansion valve 14 to become a low temperature. exchanged, thereby being further cooled (point 5 of Figure 2). Afterwards, the refrigerant is decompressed to a low pressure by the first expansion valve 11 and becomes a two-phase refrigerant (point 6 in Figure 2), and then flows into the outdoor heat exchanger 12 as an evaporator, where it absorbs heat and undergoes evaporation and gasification. (Point 7 of Figure 2). Then, it passes through the four-way valve 4 , exchanges heat with the high-pressure refrigerant in the first internal heat exchanger 9 , is further heated (point 8 in FIG. 2 ), and is sucked into the compressor 3 .

On the other hand, the refrigerant diverted to the injection circuit 13 is decompressed to an intermediate pressure by the third expansion valve 14 and becomes a low-temperature two-phase refrigerant (point 9 in FIG. 2 ), and then passes through the second internal heat exchanger 10 It exchanges heat with the high-pressure refrigerant, is heated (point 10 in FIG. 2 ), and is sprayed to the compressor 3 .

Inside the compressor 3, the sucked refrigerant (point 8 in Fig. 2) is compressed to intermediate pressure and heated (point 11 in Fig. 12), is compressed to high pressure and discharged (point 1 in Figure 2).

The operation during the cooling operation will be described below based on the pH diagrams during the cooling operation shown in FIGS. 1 and 3 .

During cooling operation, the flow path of the four-way valve 4 is set in the direction of the dotted line in FIG. 1 . The high-temperature and high-pressure gas refrigerant (point 1 in FIG. 3 ) discharged from the compressor 3 passes through the four-way valve 4 and flows into the outdoor heat exchanger 12 serving as a condenser, where it condenses and liquefies while dissipating heat, and becomes a high-pressure and low-temperature refrigerant. (Point 2 of Figure 3). The refrigerant flowing out of the outdoor heat exchanger 12 undergoes some decompression in the first expansion valve 11 (point 3 in FIG. 3 ), and then exchanges with the low-temperature refrigerant flowing into the injection circuit 13 in the second internal heat exchanger 10 . After heat exchange, it is cooled (point 4 in FIG. 3 ), where, after a part of the refrigerant is diverted to the injection circuit 13, it is then heated in the first internal heat exchanger 9 with the refrigerant sucked into the compressor 3. Cooled after exchange (point 5 of Figure 3).

Then, after being decompressed to a low pressure by the second expansion valve 8 and becoming a two-phase refrigerant (point 6 in FIG. 3 ), it flows out of the outdoor unit 1 and flows into the indoor unit 2 through the liquid pipe 7 . Then, it flows into the indoor heat exchanger 6 which becomes an evaporator, absorbs heat there, evaporates and gasifies (point 7 in FIG. 3 ), and supplies cooling to load-side media such as air and water on the indoor unit 2 side.

The low-pressure gas refrigerant flowing out of the indoor heat exchanger 6 flows out of the indoor unit 2, flows into the outdoor unit 1 through the gas pipe 5, passes through the four-way valve 4, exchanges heat with the high-pressure refrigerant in the first internal heat exchanger 9, and is heated After (point 8 in Figure 3), it is sucked into the compressor 3.

On the other hand, the refrigerant diverted to the injection circuit 13 is decompressed to an intermediate pressure by the third expansion valve 14, and becomes a low-temperature two-phase refrigerant (point 9 in FIG. 3 ), and then passes through the second internal heat exchanger 10 It exchanges heat with the high-pressure refrigerant, is heated (point 10 in FIG. 3 ), and is sprayed to the compressor 3 . Inside the compressor 3, the sucked refrigerant (point 8 in Fig. 3) is compressed to intermediate pressure, heated (point 11 in Fig. Point 12), is compressed again to high pressure and discharged (point 1 in Figure 3).

The pH diagram during the cooling operation is substantially the same as that during the heating operation, and the same operation can be realized regardless of the operation mode.

The operation control operation in this refrigerating and air-conditioning apparatus will be described below.

First, the control operation during the heating operation will be described based on the flowchart in FIG. 4 .

When heating operation is performed, the capacity of the compressor 3, the opening degrees of the first expansion valve 11, the opening degrees of the second expansion valve 8, and the opening degrees of the third expansion valve 14 are first set to initial values (step S1).

Then, after a predetermined time has elapsed from this point (step S2), each actuator is controlled as follows according to the subsequent operation state.

In addition, the capacity of the compressor 3 is controlled so that the air temperature measured by the temperature sensor 16j of the indoor unit 2 reaches the temperature set by the user of the refrigerating and air-conditioning apparatus in principle.

That is, the air temperature of the indoor unit 2 is compared with the set value (step S3). When the air temperature is the same as or close to the set temperature, keep the capacity of the compressor 3 unchanged and proceed to the next step.

And change the capacity of the compressor 3, so that the capacity of the compressor 3 is increased when the air temperature is much lower than the set temperature, and keep the capacity of the compressor 3 unchanged when the air temperature is close to the set temperature. When the air temperature is higher than the set temperature, the capacity of the compressor 3 is decreased (step S4).

The control of each expansion valve is performed as follows.

First, the second expansion valve 8 is controlled so that the refrigerant subcooling degree SC at the outlet of the indoor heat exchanger 6 reaches a preset target value (for example, 10°C), and the refrigerant subcooling degree SC is detected by using the temperature sensor 16h. The saturation of the high-pressure refrigerant is obtained by using the temperature difference between the temperature and the outlet temperature of the indoor heat exchanger 6 detected by the temperature sensor 16i.

That is, the refrigerant subcooling degree SC at the outlet of the indoor heat exchanger 6 is compared with the target value (step S5). When the refrigerant subcooling degree SC at the outlet of the indoor heat exchanger 6 is equal to or close to the target value, keep the opening degree of the second expansion valve 8 unchanged and proceed to the next step.

In addition, the opening degree of the second expansion valve 8 is increased when the refrigerant subcooling degree SC at the outlet of the indoor heat exchanger 6 is larger than the target value, and is narrowed when the refrigerant subcooling degree SC is smaller than the target value. According to the opening degree of the second expansion valve 8, the opening degree of the second expansion valve 8 is changed (step 6).

Then, the first expansion valve 11 is controlled so that the degree of superheat SH of the refrigerant sucked by the compressor 3 reaches a preset target value (for example, 10° C.). The temperature difference between the suction temperature and the saturation temperature of the low-pressure refrigerant detected by the temperature sensor 16c is obtained.

That is, the degree of superheat SH of the refrigerant sucked by the compressor 3 is compared with the target value (step S7). When the degree of superheat SH of the refrigerant sucked by the compressor 3 is the same as or close to the target value, keep the opening degree of the first expansion valve 11 unchanged and proceed to the next step.

Then, the opening degree of the first expansion valve 11 is increased when the degree of superheat SH of the refrigerant sucked by the compressor 3 is larger than the target value, and the opening degree of the first expansion valve 11 is reduced when the degree of superheat SH of the refrigerant is smaller than the target value. The opening degree of the first expansion valve 11 is changed (step S8).

Then, the third expansion valve 14 is controlled so that the discharge temperature of the compressor 3 detected by the temperature sensor 16a becomes a preset target value (for example, 90° C.).

That is, the discharge temperature of the compressor 3 is compared with the target value (step S9). When the discharge temperature of the compressor 3 is equal to or close to the target value, the opening degree of the third expansion valve 14 is kept constant, and the process returns to step S2.

Changes in the state of the refrigerant when changing the opening degree of the third expansion valve 14 are as follows.

As the opening degree of the third expansion valve 14 increases, the refrigerant flow rate flowing into the injection circuit 13 increases. Since the amount of heat exchange in the second internal heat exchanger 10 does not change greatly due to the flow rate of the injection circuit 13, when the refrigerant flow rate flowing into the injection circuit 13 increases, the injection in the second internal heat exchanger 10 The refrigerant enthalpy difference on the circuit 13 side (difference from point 9→10 in FIG. 2 ) becomes smaller, and the injected refrigerant enthalpy (point 10 in FIG. 2 ) decreases.

Therefore, the enthalpy of the refrigerant enthalpy (point 12 in FIG. 2 ) after the injected refrigerant merges also decreases, and as a result, the discharge enthalpy of the compressor 3 (point 1 in FIG. 2 ) also decreases, and the compressor 3 3 The discharge temperature is lowered.

Conversely, when the opening degree of the third expansion valve 14 decreases, the discharge enthalpy of the compressor 3 increases, and the discharge temperature of the compressor 3 increases. Therefore, the opening degree of the third expansion valve 14 is controlled to increase the opening degree of the third expansion valve 14 when the discharge temperature of the compressor 3 is higher than the target value, and vice versa when the discharge temperature is lower than the target value. The mode of reducing the opening degree of the third expansion valve 14 changes the opening degree of the third expansion valve 14 (step S10 ), and then returns to step S2 .

Next, the control operation during the cooling operation will be described based on the flowchart in FIG. 5 .

In cooling operation, the capacity of the compressor 3, the openings of the first expansion valve 11, the openings of the second expansion valve 8, and the openings of the third expansion valve 14 are first set to initial values (step S11).

After a predetermined time has elapsed from this point (step S12), each actuator is controlled as follows according to the subsequent operation state.

First, the capacity of the compressor 3 is controlled so that, in principle, the air temperature measured by the temperature sensor 16j of the indoor unit 2 is equal to the temperature set by the user of the refrigerating and air-conditioning apparatus.

That is, the air temperature of the indoor unit 2 is compared with the set temperature (step S13). When the air temperature is the same as or close to the set temperature, keep the capacity of the compressor 3 unchanged and proceed to the next step.

And the capacity of the compressor 3 is changed so that when the air temperature is significantly higher than the set temperature, the capacity of the compressor 3 is increased, and when the air temperature is lower than the set temperature, the capacity of the compressor 3 is decreased ( Step S14).

The control of each expansion valve is performed as follows.

First, the first expansion valve 11 is controlled so that the refrigerant subcooling degree SC at the outlet of the outdoor heat exchanger 12 reaches a preset target value (for example, 10°C), and the refrigerant subcooling degree SC is detected by the temperature sensor 16c. The temperature difference between the saturation temperature of the high-pressure refrigerant and the outlet temperature of the outdoor heat exchanger 12 detected by the temperature sensor 16d is obtained.

That is, the refrigerant subcooling degree SC at the outlet of the outdoor heat exchanger 12 is compared with the target value (step S15). When the refrigerant subcooling degree SC at the outlet of the outdoor heat exchanger 12 is equal to or close to the target value, keep the opening degree of the first expansion valve 11 unchanged and proceed to the next step.

In addition, the opening degree of the first expansion valve 11 is increased when the degree of refrigerant subcooling SC at the outlet of the outdoor heat exchanger 12 is greater than the target value, and the opening degree of the first expansion valve 11 is decreased when the degree of refrigerant subcooling SC is smaller than the target value. In accordance with the opening degree of the first expansion valve 11, the opening degree of the first expansion valve 11 is changed (step S16).

Then, the second expansion valve 8 is controlled so that the degree of superheat SH of the refrigerant sucked by the compressor 3 reaches a preset target value (for example, 10° C.). The temperature difference between the suction temperature and the saturation temperature of the low-pressure refrigerant detected by the temperature sensor 16h is obtained.

That is, the degree of superheat SH of the refrigerant sucked by the compressor 3 is compared with the target value (step S17). When the degree of superheat SH of the refrigerant sucked by the compressor 3 is the same as or close to the target value, keep the opening degree of the second expansion valve 8 unchanged and proceed to the next step.

In addition, the opening degree of the second expansion valve 8 is increased when the degree of superheat SH of the refrigerant sucked by the compressor 3 is larger than the target value, and the opening degree of the second expansion valve 8 is reduced when the degree of superheat SH of the refrigerant is smaller than the target value. The opening degree of the second expansion valve 8 is changed (step S18).

Then, the third expansion valve 14 is controlled so that the discharge temperature of the compressor 3 detected by the temperature sensor 16a becomes a preset target value (for example, 90° C.).

That is, the discharge temperature of the compressor 3 is compared with the target value (step S19). When the discharge temperature of the compressor 3 is equal to or close to the target value, the opening degree of the third expansion valve 14 is kept constant, and the process returns to step S12.

In addition, since the state change of the refrigerant when the opening degree of the third expansion valve 14 is changed is the same as that during the heating operation, the temperature of the third expansion valve 14 is increased when the discharge temperature of the compressor 3 is higher than the target value. On the contrary, when the discharge temperature is lower than the target value, the opening degree of the third expansion valve 14 is reduced, and the opening degree of the third expansion valve 14 is changed (step S20), and the process returns to step S12.

Hereinafter, the circuit configuration and the effects achieved by the control of the present embodiment will be described. In the configuration of this apparatus, since the same operation is performed regardless of the cooling operation or the heating operation, the heating operation will be particularly described below.

The circuit configuration of this device is a so-called gas injection circuit. That is, it is a structure in which the gaseous refrigerant of the refrigerant depressurized to an intermediate pressure after flowing out of the indoor heat exchanger 6 serving as a condenser is sprayed to the compressor 3 .

Generally speaking, the structure of separating the intermediate-pressure refrigerant into liquid and gas in the gas-liquid separator is often used, but as shown in Fig. A structure in which liquid and gas are thermally separated and sprayed by heat exchange in the medium.

By forming the gas injection circuit, the following effects can be obtained.

First, the gas injection increases the refrigerant flow rate discharged from the compressor 3, and the refrigerant flow rate Gdis discharged from the compressor 3=the refrigerant flow rate Gsuc sucked by the compressor 3+the injected refrigerant flow rate Ginj.

Therefore, since the flow rate of the refrigerant flowing into the heat exchanger serving as the condenser increases, the heating capacity increases in the heating operation.

On the other hand, by the heat exchange in the second internal heat exchanger 10, as shown in FIG. 6, the enthalpy of the refrigerant flowing into the heat exchanger serving as the evaporator decreases, and the difference in enthalpy of the refrigerant in the evaporator increases. big. Therefore, the cooling capacity also increases during the cooling operation.

Furthermore, even when gas injection is performed, an effect of improving efficiency can be obtained.

The refrigerant flowing into the evaporator is generally a gas-liquid two-phase refrigerant, but the gas refrigerant has no effect on the refrigeration capacity. Seen from the compressor 3, the compressor 3 performs an operation of raising the pressure of the low-pressure gas refrigerant together with the evaporated gas refrigerant in the evaporator to a high pressure.

When the gas injection is performed, a part of the gas refrigerant flowing into the evaporator is extracted at an intermediate pressure, injected, raised from the intermediate pressure to a high pressure, and compressed.

Therefore, there is no need to perform compression work for increasing the flow rate of the injected gas refrigerant from the low pressure to the intermediate pressure, and the efficiency of this part can be improved. This effect can be obtained in any operation of cooling and heating.

The correlation between the gas injection flow rate and the heating capacity will be described below.

When the gas injection flow rate is increased, as described above, the flow rate of the refrigerant discharged from the compressor 3 increases, the discharge temperature of the compressor 3 decreases, and the temperature of the refrigerant flowing into the condenser also decreases.

Let's look at the heat exchange performance of the condenser. Generally speaking, the higher the temperature distribution in the heat exchanger, the higher the heat exchange capacity. Changes in refrigerant temperature when the refrigerant temperature at the condenser inlet is different at the same condensing temperature As shown in FIG. 7 , the temperature distribution of the part where the refrigerant becomes a superheated gas in the condenser changes.

In the condenser, the heat exchange amount when the refrigerant is in the condensing temperature and the two-phase state accounts for the majority, but the heat exchange amount of the superheated gas state also accounts for about 20% to 30% of the whole, which has a great influence on the heat exchange amount. big.

If the injection flow rate is too much and the temperature of the refrigerant in the superheated gas part is significantly lowered, the heat exchange performance of the condenser will decrease, and the heating capacity will also decrease. FIG. 8 shows the above-mentioned correlation between the gas injection flow rate and the heating capacity, and there is a gas injection flow rate at which the heating capacity is maximum.

Hereinafter, the effect of the first internal heat exchanger 9 of the present embodiment will be described.

In the first internal heat exchanger 9, the high-pressure liquid refrigerant flowing out of the condenser and the suction refrigerant of the compressor 3 perform heat exchange. Since the high-pressure liquid refrigerant is cooled in the first internal heat exchanger 9, the enthalpy of the refrigerant flowing into the evaporator decreases, and thus, the difference in enthalpy of the refrigerant in the evaporator increases.

Therefore, the cooling capacity during the cooling operation increases.

On the other hand, the refrigerant sucked into the compressor 3 is heated, and the suction temperature rises. The discharge temperature of the compressor 3 also rises accordingly. In addition, in the compression process of the compressor 3, generally, more work is required than when compressing the high-temperature refrigerant even when the same boost is performed.

Therefore, the impact of setting the first internal heat exchanger 9 on the efficiency surface is manifested in two aspects: the capacity increase brought about by the increase of the evaporator enthalpy difference and the increase of the compression work. When the influence of the increase is large, the operating efficiency of the device increases.

Hereinafter, the effect in the case of combining the heat exchange in the first internal heat exchanger 9 and the gas injection in the injection circuit 13 as shown in this embodiment will be described.

When the heat exchange in the first internal heat exchanger 9 is performed, the suction temperature of the compressor 3 rises. Therefore, in the change inside the compressor 3 during injection, the enthalpy of the refrigerant (point 11 in FIGS. 2 and 3 ) rising from the low pressure to the intermediate pressure increases, and the enthalpy of the refrigerant after merging with the injected refrigerant increases. (Fig. 2, point 12 in Fig. 3) also improves.

Therefore, the discharge enthalpy (point 1 in FIGS. 2 and 3 ) of the compressor 3 also increases, and the discharge temperature of the compressor 3 rises. Therefore, depending on whether there is heat exchange by the first internal heat exchanger 9, the relationship between the gas injection flow rate and the heating capacity changes as shown in FIG. 9 .

In the case of heat exchange with the first internal heat exchanger 9, since the discharge temperature of the compressor 3 increases when the same injection amount is performed, the temperature of the refrigerant at the inlet of the condenser also increases, and the heat exchange amount of the condenser increases, Heating capacity increased. Therefore, the jet flow rate forming the peak heating capacity increases, the peak heating capacity itself also increases, and more heating capacity can be obtained.

Also, even when the first internal heat exchanger 9 is not present, the discharge temperature of the compressor 3 can be raised by controlling the opening of the first expansion valve 11 to increase the suction superheat of the compressor 3 .

However, in this case, since the degree of superheat of the refrigerant at the outlet of the outdoor heat exchanger 12 serving as the evaporator also increases simultaneously, the heat exchange efficiency of the outdoor heat exchanger 12 decreases.

Once the heat exchange efficiency of the outdoor heat exchanger 12 decreases, in order to obtain the same amount of heat exchange, the evaporation temperature must be lowered, and an operation in which the low pressure is lowered is formed.

When the low pressure decreases, the flow rate of the refrigerant sucked by the compressor 3 also decreases. Therefore, if such an operation is performed, the heating capacity will decrease on the contrary.

Conversely, if the first internal heat exchanger 9 is used, the state of the refrigerant at the outlet of the outdoor heat exchanger 12 as an evaporator becomes an appropriate state, and the compressor 3 can be operated while maintaining a good heat exchange efficiency. The discharge temperature rises, avoiding the above-mentioned drop in low pressure, and increasing the heating capacity can be easily realized.

In addition, the circuit structure of the present embodiment employs a structure in which a part of the high-pressure refrigerant is divided and depressurized, superheated and gasified in the second internal heat exchanger 10 , and sprayed.

Therefore, compared with the case of injecting the gas separated by the gas-liquid separator as in the conventional example, the refrigerant amount distribution does not change even when the injection amount changes according to the control and operating conditions, so that more stable operation can be realized.

In addition, as mentioned above, the third expansion valve 14 is controlled so that the discharge temperature of the compressor 3 becomes equal to the target value, and the control target value is set so as to maximize the heating capacity.

As shown in FIG. 9 , since there is a discharge temperature at which the heating capability is maximized from the correlation of gas injection flow rate-heating capacity-discharge temperature, the discharge temperature is obtained in advance and set as a target value. In addition, the target value of the discharge temperature does not need to be a constant value, and may be changed at any time according to operating conditions and equipment characteristics such as a condenser.

In this way, by controlling the discharge temperature, the gas injection amount can be controlled to maximize the heating capacity.

The gas injection amount can be controlled not only to maximize the heating capacity but also to maximize the operating efficiency.

In the case where a large amount of heating capacity is required, such as starting a refrigeration and air-conditioning unit, the capacity is controlled to the maximum, but when the room temperature rises due to heating after the unit has been in operation for a certain period of time, such a large heating capacity is not needed , so in this case the control becomes the most efficient.

There is a correlation between the injection flow rate, heating capacity, and operating efficiency as shown in FIG. 10 , and when the operating efficiency is maximum, the injection flow rate decreases and the discharge temperature increases compared to the case where the heating capacity is maximum.

In the injection flow with the maximum heating capacity, the heat exchange performance of the condenser decreases due to the decrease of the discharge temperature, and in order to increase the injection flow, the intermediate pressure decreases and the compression work of the compressed injection part increases. In this way, the operating efficiency is Compared with the largest case, the efficiency is reduced.

Therefore, as the discharge temperature target value controlled by the third expansion valve 14 of the injection circuit 13, there is not only a target value for the maximum heating capacity, but also a target value for the maximum operating efficiency. Operating capacity and indoor unit side air temperature conditions, etc.), when the heating capacity is required, the target value is set to the maximum heating capacity, otherwise the target value is set to the maximum operation efficiency.

By performing such an operation, it is possible to perform high-efficiency operation of the device while realizing a large amount of heating capacity.

In addition, the first expansion valve 11 is controlled so that the suction superheat degree of the compressor 3 reaches a target value, and by this control, the optimum superheat degree at the outlet of the heat exchanger serving as the evaporator can be formed, thereby ensuring a high temperature in the evaporator. Excellent heat exchange performance and moderate refrigerant enthalpy can be ensured for operation, enabling high-efficiency operation.

Although the degree of superheat at the outlet of the evaporator that operates in this way varies due to the characteristics of the heat exchanger, it is about 2°C. Since the refrigerant is heated in the first internal heat exchanger 9 afterwards, the compressor 3 The target value of the degree of suction superheat is higher than this value, for example, the above-mentioned 10° C. is set as the target value.

Therefore, for the first expansion valve 11, the degree of superheat at the outlet of the evaporator and the degree of superheat at the outlet of the outdoor heat exchanger 12 obtained from the temperature difference between the temperature sensor 16b and the temperature sensor 16c during the heating operation are controlled so as to reach a target value (for example, the above-mentioned 2°C).

However, when the degree of superheat at the outlet of the evaporator is directly controlled, if the target value is a low value of about 2°C, the outlet of the evaporator transitions into a gas-liquid two-phase state, and the degree of superheat cannot be detected accurately. , Difficult to control problems.

If the suction superheat of the compressor 3 is used for detection, a high target value can be set, and the suction refrigerant will not become a gas-liquid two-phase due to heating in the first internal heat exchanger 9, and cannot be accurately By detecting the condition of superheat, control can be performed more easily and more stable control can be performed.

In addition, the second expansion valve 8 is controlled so that the degree of subcooling at the outlet of the indoor heat exchanger 6 serving as the condenser reaches a target value, and by this control, high heat exchange performance in the condenser can be ensured, and refrigeration can be appropriately ensured. The operation is performed with a poor enthalpy of the agent, and high-efficiency operation is possible.

The degree of subcooling at the outlet of the condenser that operates in this way varies depending on the characteristics of the heat exchanger, but it is about 5 to 10°C.

In addition, by setting the target value of the degree of subcooling higher than this value, for example, about 10 to 15°C, it is also possible to perform an operation to increase the heating capacity.

Therefore, the target value of the subcooling degree can also be changed according to the operating conditions. When starting the device, a higher target value of the subcooling degree can be used to ensure the heating capacity, and a lower target value of the subcooling degree can be used for high-efficiency operation when the room temperature is stable.

In addition, the refrigerant used in refrigeration and air-conditioning equipment is not limited to R410A, and other refrigerants such as R134a, R404A, and R407C of HFC refrigerants, CO ₂ of natural refrigerants, HC refrigerants, ammonia, air, and water can also be used. . Especially for the shortcomings of the refrigerant enthalpy difference in the evaporator is small and the operating efficiency is reduced when _CO2 is used as the refrigerant, the structure of the device can be improved by the first internal heat exchanger 9 and the second internal heat exchanger 10 The enthalpy difference of the evaporator is enlarged, so the efficiency can be greatly improved, and this device is suitable for use.

And, in the case of using _CO2 , there is no condensation temperature, and in the high-pressure side heat exchanger as a radiator, the temperature decreases with the flow. Therefore, the change in the heat exchange amount in the radiator is greatly affected by the inlet temperature, unlike HFC-based refrigerants, which have a condensing temperature in a certain range and can secure a certain amount of heat exchange amount.

Therefore, as in this embodiment, by adopting a structure that can increase the injection flow rate while increasing the discharge temperature, the increase rate of the heating capacity is higher than that of HFC refrigerants, and CO2 is also suitable for use in this device.

Furthermore, the installation positions of the first internal heat exchanger 9 and the second internal heat exchanger 10 are not limited to the structure shown in FIG. 1 , and the same effect can be obtained even if the upstream and downstream positional relationship is reversed. In addition, the position where the injection circuit 13 is installed is not limited to the position shown in FIG. 1 , and the same effect can be obtained at other intermediate pressure parts and high pressure liquid parts.

In addition, considering the control stability of the third expansion valve 14, the injection circuit 13 is preferably installed at a position where a liquid is completely formed instead of a gas-liquid two-phase state.

In addition, in this embodiment, since the installation positions of the first internal heat exchanger 9, the second internal heat exchanger 10, and the injection circuit 13 are provided between the first expansion valve 11 and the third expansion valve 8, in The same injection operation can be performed in any of the heating and cooling modes.

In addition, although the refrigerant temperature sensor between the condenser and the evaporator is used to detect the saturation temperature of the refrigerant, it is also possible to install a pressure sensor for detecting high and low pressures, convert the detected pressure value, and obtain the saturation temperature.

second embodiment

The following second embodiment of the present invention is shown in FIG. 11 . Fig. 11 is a refrigerant circuit diagram of a refrigerating and air-conditioning apparatus according to a second embodiment. The medium-pressure accumulator 17 is installed in the outdoor unit, and the suction pipe of the compressor 3 passes through the inside.

The heat exchange between the refrigerant forming the penetrating portion and the refrigerant in the medium-pressure accumulator 17 has the same function as that of the first internal heat exchanger 9 in the first embodiment.

The functions and effects of this embodiment are the same as those of the first embodiment except for the medium-voltage storage device 17 , and therefore, the description thereof will be omitted. During the heating operation, the gas-liquid two-phase refrigerant at the outlet of the indoor exchanger 6 flows into the medium-pressure accumulator 17, cools in the medium-pressure accumulator 17, and flows out as a liquid. During cooling operation, the gas-liquid two-phase refrigerant flowing out of the first expansion valve 11 flows into the medium-pressure accumulator 17 , is cooled in the medium-pressure accumulator 17 , and flows out as a liquid.

The heat exchange in the medium-pressure accumulator 17 is mainly that the gas refrigerant in the gas-liquid two-phase refrigerant contacts the suction pipe, condenses and liquefies, and performs heat exchange. Therefore, the smaller the amount of liquid refrigerant remaining in the medium-pressure accumulator 17, the larger the contact area between the gas refrigerant and the suction pipe, increasing the amount of heat exchange. Conversely, if the amount of liquid refrigerant remaining in the medium-pressure accumulator 17 is large, the contact area between the gas refrigerant and the suction pipe decreases, and the amount of heat exchange decreases.

In this way, the following effects are obtained due to the presence of the medium-voltage storage device 17 .

First, since liquid is formed at the outlet of the medium-pressure accumulator 17, the refrigerant flowing into the third expansion valve 14 will inevitably form liquid refrigerant during the heating operation, so the flow rate characteristics of the third expansion valve 14 are stable, and stable control can be ensured. performance and stable device operation.

Furthermore, heat exchange in the medium pressure accumulator 17 stabilizes the pressure of the intermediate pressure accumulator 17, stabilizes the inlet pressure of the third expansion valve 14, and stabilizes the refrigerant flow rate into the injection circuit 13. For example, if the high pressure changes due to a load change, the pressure in the medium pressure accumulator 17 changes accordingly, but the pressure change can be suppressed by heat exchange in the medium pressure accumulator 17 .

Once the load increases and the high pressure rises, the pressure in the medium pressure storage 17 also rises, but at this time, because the pressure difference with the low pressure increases, the temperature difference in the heat exchanger in the medium pressure storage 17 also increases, so the heat exchange amount increases . When the amount of heat exchange increases, the amount of gas refrigerant condensed in the gas-liquid two-phase refrigerant flowing into the medium-pressure accumulator 17 increases, so that the pressure does not easily increase, and the pressure increase of the intermediate-pressure accumulator 17 can be suppressed.

Conversely, once the load decreases and the high pressure decreases, the pressure in the medium pressure storage 17 also decreases, but at this time the pressure difference with the low pressure becomes smaller, and the temperature difference in the heat exchanger in the medium pressure storage 17 also decreases, so the heat exchange The volume is reduced. When the amount of the heat exchanger decreases, the amount of gas refrigerant condensed in the gas-liquid two-phase refrigerant flowing into the medium-pressure accumulator 17 decreases, so the pressure drop is less likely to occur, and the pressure drop of the intermediate-pressure accumulator 17 can be suppressed.

As described above, by performing heat exchange in the medium pressure accumulator 17 , a change in the amount of heat exchange due to a change in the operating state is automatically generated, and as a result, a change in pressure in the medium pressure accumulator 17 can be suppressed.

In addition, by exchanging heat in the medium-voltage accumulator 17, there is also an effect of stabilizing the operation of the device itself. For example, when the state of the low-pressure side changes and the degree of superheat of the refrigerant at the outlet of the outdoor heat exchanger 12 as an evaporator increases, the temperature difference during heat exchange in the medium-pressure accumulator 17 decreases, so the heat exchange As the amount decreases, the gas refrigerant is not easy to condense, so the amount of gas refrigerant in the medium-pressure storage 17 increases and the amount of liquid refrigerant decreases.

The reduced amount of liquid refrigerant moves to the outdoor heat exchanger 12, and the amount of liquid refrigerant in the outdoor heat exchanger 12 increases, thereby suppressing an increase in the degree of superheat of the refrigerant at the outlet of the outdoor heat exchanger 12 and suppressing changes in the operation of the device.

Conversely, when the state of the low-pressure side changes and the degree of superheat of the refrigerant at the outlet of the outdoor heat exchanger 12 as an evaporator decreases, the heat exchange amount increases due to the increase in the temperature difference during heat exchange in the medium-pressure accumulator 17 . increases, the gas refrigerant is easy to condense, so the amount of gas refrigerant in the medium-pressure storage 17 decreases and the amount of liquid refrigerant increases. This part of the amount of liquid refrigerant moves from the outdoor heat exchanger 12, thereby reducing the amount of liquid refrigerant in the outdoor heat exchanger 12, so that the degree of superheat of the refrigerant at the outlet of the outdoor heat exchanger 12 can be suppressed from decreasing, and the operation of the device can be suppressed. .

This effect of suppressing changes in the degree of superheat is also produced by performing heat exchange in the medium-pressure accumulator 17 to automatically generate a change in the amount of heat exchange as the operating state changes.

As described above, by performing the heat exchange performed in the first internal heat exchanger 9 in the first embodiment in the medium-pressure accumulator 17, even if the operation of the device changes, it can be suppressed by the automatic heat exchange amount change. Changes, stable device operation.

In addition, although the heat exchange is performed in the medium-pressure accumulator 17 , the same effect can be obtained regardless of the structure as long as the heat exchange is performed with the refrigerant in the intermediate-pressure accumulator 17 . For example, a structure may be employed in which the suction pipe of the compressor 3 is brought into contact with the outer periphery of the container of the medium pressure accumulator 17 to exchange heat.

In addition, the refrigerant supplied to the injection circuit 13 may be supplied from the bottom of the medium pressure accumulator 17 . In this case, liquid refrigerant flows into the third expansion valve 14 during each cooling and heating operation, so the flow rate characteristics of the third expansion valve 14 are stable regardless of whether it is in the cooling operation or the heating operation. , which ensures control stability.

Claims (26)

1. heat pump assembly, has refrigerant loop, in this refrigerant loop, the heat exchanger (12) of cold-producing medium heat absorption will be made, suck the compressor (3) of cold-producing medium from above-mentioned heat exchanger (12), the cross valve (4) that the cold-producing medium of discharging from above-mentioned compressor (3) passes through, make from the heat exchanger (6) of the refrigerant loses heat of above-mentioned compressor (3) discharge, and reduction is connected from the expansion valve (11) that above-mentioned heat exchanger (6) flows to the pressure of the cold-producing medium the above-mentioned heat exchanger (12), so that cold-producing medium circulation, the heat that utilization discharges from above-mentioned heat exchanger (6), it is characterized in that this heat pump assembly has:

Memory (9) stores the cold-producing medium that flows to above-mentioned heat exchanger (12) from above-mentioned heat exchanger (6), and, between the cold-producing medium of above-mentioned compressor (3), carry out heat exchange at the cold-producing medium of this storage and from above-mentioned heat exchanger (12);

Bypass path (13) makes from the part of above-mentioned heat exchanger (6) towards the mobile cold-producing medium of above-mentioned heat exchanger (12), is inhaled into above-mentioned compressor (3) with the above-mentioned heat exchanger of process (12) and is compressed into middle cold-producing medium interflow of pressing;

Expansion valve (14) is arranged in the above-mentioned bypass path (13), is used for reducing the pressure of the cold-producing medium that flows through above-mentioned bypass path (13);

Heat exchanger (10) is arranged in above-mentioned refrigerant loop and the above-mentioned bypass path (13), will give the cold-producing medium that flows through above-mentioned bypass path (13) towards the heat of the mobile cold-producing medium of above-mentioned heat exchanger (12) from above-mentioned heat exchanger (6);

Be used for the temperature sensor (16a) of detection from the temperature of the cold-producing medium of above-mentioned compressor (3) discharge; And

Control device (15) is controlled the aperture of above-mentioned expansion valve (14), makes the temperature of the cold-producing medium that is detected by said temperature sensor (16a) consistent with the desired value of predefined discharge temperature.

2. heat pump assembly as claimed in claim 1 is characterized in that the desired value of above-mentioned discharge temperature is set at the temperature amplitude with regulation.

3. heat pump assembly as claimed in claim 1 or 2 is characterized in that, the cold-producing medium that flows through above-mentioned bypass path (13) becomes the gas-liquid two-phase state under the effect of above-mentioned expansion valve (14).

4. as each described heat pump assembly in the claim 1 to 3, it is characterized in that between above-mentioned heat exchanger (6) and above-mentioned memory (9), having expansion valve (8).

5. heat pump assembly as claimed in claim 4 is characterized in that, above-mentioned expansion valve (8) is used to make from the pressure reduction of above-mentioned heat exchanger (6) towards the mobile cold-producing medium of above-mentioned memory (9).

6. as each described heat pump assembly in the claim 1 to 5, it is characterized in that above-mentioned bypass path (13) is from branch between above-mentioned heat exchanger (6) and the above-mentioned expansion valve (11).

7. heat pump assembly as claimed in claim 6 is characterized in that, above-mentioned bypass path (13) is from branch between above-mentioned memory (9) and the above-mentioned heat exchanger (10).

8. as each described heat pump assembly in the claim 1 to 7, it is characterized in that above-mentioned heat exchanger (6) is a condenser.

9. as each described heat pump assembly in the claim 1 to 8, it is characterized in that, add hot-air by utilizing above-mentioned heat exchanger (6) that the cold-producing medium of discharging from above-mentioned compressor (3) is dispelled the heat.

10. as each described heat pump assembly in the claim 1 to 8, it is characterized in that, add hot water by utilizing above-mentioned heat exchanger (6) that the cold-producing medium of discharging from above-mentioned compressor (3) is dispelled the heat.

11. as each described heat pump assembly in the claim 1 to 10, it is characterized in that, above-mentioned control device (15) is higher than under the situation of desired value in the discharge temperature of the cold-producing medium that is detected by above-mentioned discharge temperature sensor (16a), control increases the aperture of above-mentioned expansion valve (14), make the enthalpy of cold-producing medium reduce, discharge temperature at the cold-producing medium that is detected by above-mentioned discharge temperature sensor (16a) is lower than under the situation of desired value, control reduces the aperture of above-mentioned expansion valve (14), makes the enthalpy of cold-producing medium rise.

12. as each described heat pump assembly in the claim 1 to 11, it is characterized in that the temperature sensor (16c) and being used to temperature of the cold-producing medium that is used to detect above-mentioned heat exchanger (12) detects the temperature sensor (16b) of temperature of the cold-producing medium of above-mentioned heat exchanger (12) outlet side;

The temperature that temperature that above-mentioned control device (15) detects according to said temperature sensor (16c) and said temperature sensor (16b) detect is obtained the refrigerant superheat degree of above-mentioned heat exchanger (12) outlet side, and so that the mode that this refrigerant superheat degree becomes the desired value of predefined refrigerant superheat degree is controlled above-mentioned expansion valve (11).

13. as each described heat pump assembly in the claim 1 to 11, it is characterized in that the temperature sensor (16c) and being used for temperature of the cold-producing medium that is used to detect above-mentioned heat exchanger (12) detects the temperature sensor (16f) of the temperature of the cold-producing medium that flow into above-mentioned compressor (3);

The temperature that temperature that above-mentioned control device (15) detects according to said temperature sensor (16c) and said temperature sensor (16f) detect is obtained the refrigerant superheat degree of above-mentioned compressor (3) suction portion, and so that the mode that this refrigerant superheat degree becomes the desired value of predefined refrigerant superheat degree is controlled above-mentioned expansion valve (11).

14. the off-premises station of a heat pump assembly, has refrigerant loop, in this refrigerant loop, the heat exchanger (12) of cold-producing medium heat absorption will be made, suck cold-producing medium and cold-producing medium is discharged to compressor (3) the heat exchanger (6) that makes refrigerant loses heat from above-mentioned heat exchanger (12) by cross valve (4), and reduction is connected from the expansion valve (11) that above-mentioned heat exchanger (6) flows to the pressure of the cold-producing medium the above-mentioned heat exchanger (12), so that cold-producing medium circulation, the heat that utilization discharges from above-mentioned heat exchanger (6), it is characterized in that the off-premises station of this heat pump assembly has:

Memory (9) stores the cold-producing medium that flows to above-mentioned heat exchanger (12) from above-mentioned heat exchanger (6), and, between the cold-producing medium of above-mentioned compressor (3), carry out heat exchange at the cold-producing medium of this storage and from above-mentioned heat exchanger (12);

Bypass path (13) makes from the part of above-mentioned heat exchanger (6) towards the mobile cold-producing medium of above-mentioned heat exchanger (12), is inhaled into above-mentioned compressor (3) with the above-mentioned heat exchanger of process (12) and is compressed into middle cold-producing medium interflow of pressing;

Expansion valve (14) is arranged in the above-mentioned bypass path (13), is used for reducing the pressure of the cold-producing medium that flows through above-mentioned bypass path (13);

Heat exchanger (10) is arranged in above-mentioned refrigerant loop and the above-mentioned bypass path (13), will give the cold-producing medium that flows through above-mentioned bypass path (13) towards the heat of the mobile cold-producing medium of above-mentioned heat exchanger (12) from above-mentioned heat exchanger (6);

Be used for the temperature sensor (16a) of detection from the temperature of the cold-producing medium of above-mentioned compressor (3) discharge; And

Control device (15) is controlled the aperture of above-mentioned expansion valve (14), makes the temperature of the cold-producing medium that is detected by said temperature sensor (16a) consistent with the desired value of predefined discharge temperature.

15. the off-premises station of heat pump assembly as claimed in claim 14 is characterized in that, the desired value of above-mentioned discharge temperature is set at the temperature amplitude with regulation.

16. the off-premises station as claim 14 or 15 described heat pump assemblies is characterized in that, the cold-producing medium that flows through above-mentioned bypass path (13) becomes the gas-liquid two-phase state under the effect of above-mentioned expansion valve (14).

17. the off-premises station as each described heat pump assembly in the claim 14 to 16 is characterized in that, has expansion valve (8) between above-mentioned heat exchanger (6) and above-mentioned memory (9).

18. the off-premises station of heat pump assembly as claimed in claim 17 is characterized in that, above-mentioned expansion valve (8) is used to make from the pressure reduction of above-mentioned heat exchanger (6) towards the mobile cold-producing medium of above-mentioned memory (9).

19. the off-premises station as each described heat pump assembly in the claim 14 to 18 is characterized in that, above-mentioned bypass path (13) is from branch between above-mentioned heat exchanger (6) and the above-mentioned expansion valve (11).

20. the off-premises station of heat pump assembly as claimed in claim 19 is characterized in that, above-mentioned bypass path (13) is from branch between above-mentioned memory (9) and the above-mentioned heat exchanger (10).

21. the off-premises station as each described heat pump assembly in the claim 14 to 20 is characterized in that, being arranged at outside above-mentioned heat exchanger (6) is condenser.

22. the off-premises station as each described heat pump assembly in the claim 14 to 21 is characterized in that, adds hot-air by utilizing above-mentioned heat exchanger (6) that the cold-producing medium of discharging from above-mentioned compressor (3) is dispelled the heat.

23. the off-premises station as each described heat pump assembly in the claim 14 to 21 is characterized in that, adds hot water by utilizing above-mentioned heat exchanger (6) that the cold-producing medium of discharging from above-mentioned compressor (3) is dispelled the heat.

24. off-premises station as each described heat pump assembly in the claim 14 to 23, it is characterized in that, above-mentioned control device (15) is higher than under the situation of desired value in the discharge temperature of the cold-producing medium that is detected by above-mentioned discharge temperature sensor (16a), control increases the aperture of above-mentioned expansion valve (14), make the enthalpy of cold-producing medium reduce, discharge temperature at the cold-producing medium that is detected by above-mentioned discharge temperature sensor (16a) is lower than under the situation of desired value, control reduces the aperture of above-mentioned expansion valve (14), makes the enthalpy of cold-producing medium rise.

25. off-premises station as each described heat pump assembly in the claim 14 to 24, it is characterized in that the temperature sensor (16c) and being used to temperature of the cold-producing medium that is used to detect above-mentioned heat exchanger (12) detects the temperature sensor (16b) of temperature of the cold-producing medium of above-mentioned heat exchanger (12) outlet side;

The temperature that temperature that above-mentioned control device (15) detects according to said temperature sensor (16c) and said temperature sensor (16b) detect is obtained the refrigerant superheat degree of above-mentioned heat exchanger (12) outlet side, and so that the mode that this refrigerant superheat degree becomes the desired value of predefined refrigerant superheat degree is controlled above-mentioned expansion valve (11).

26. off-premises station as each described heat pump assembly in the claim 14 to 24, it is characterized in that the temperature sensor (16c) and being used for temperature of the cold-producing medium that is used to detect above-mentioned heat exchanger (12) detects the temperature sensor (16f) of the temperature of the cold-producing medium that flow into above-mentioned compressor (3);

The temperature that temperature that above-mentioned control device (15) detects according to said temperature sensor (16c) and said temperature sensor (16f) detect is obtained the refrigerant superheat degree of above-mentioned compressor (3) suction portion, and so that the mode that this refrigerant superheat degree becomes the desired value of predefined refrigerant superheat degree is controlled above-mentioned expansion valve (11).

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