JP3059601B2 - Cooling / heating mixed engine driven heat pump system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mixed cooling / heating system in which a plurality of indoor units can be operated simultaneously for cooling and the others for heating simultaneously by a heat pump driven by an engine.

[0002]

2. Description of the Related Art A single system in which a plurality of indoor units are connected to one outdoor unit simultaneously cools a part of a plurality of rooms and heats the others simultaneously, so-called mixed cooling / heating multi-system. The load varies from room to room, and the capacity of the outdoor unit air-cooled heat exchanger as a condenser or evaporator must be adjusted accordingly. This type of system known at present is a system that drives the compressor with an electric motor, responds to this by controlling the rotation speed of the compressor and the fan at a high level, and as a condenser required for cooling. Since the difference between the maximum capacity of the evaporator required for heating and the maximum capacity of the evaporator at the time of heating and the appropriate capacity at the time of mixed operation is large, in addition to the above-described control, for example, the air-cooled heat exchanger is divided into three parts having different capacities. Attempts have also been made to change these combinations with solenoid valves to accommodate the required imbalance in cooling / heating capacity.

[0003] However, in the above-mentioned conventional technology, the control becomes very complicated and the configuration of the system becomes complicated in order to perform the appropriate capacity adjustment. Furthermore, when the operation is performed with the rotation speed of the fan extremely reduced, there is a problem that the operation is easily affected by the wind and the installation location, and it has been difficult to appropriately cope with a wide range of operation.

[0004]

SUMMARY OF THE INVENTION The present invention focuses on the driving engine cooling water peculiar to an engine driving heat pump system, and utilizes the waste heat to control the cooling / heating capacity in a well-balanced manner. It was made to solve such a problem.

[0005]

In order to achieve the above object, according to a first aspect of the present invention, when a heating / cooling operation of an air-conditioning / combination type engine-driven heat pump system is mainly performed, the heat exchanger of the indoor unit is used. The difference in capacity between each cooling-side heat exchanger functioning as an evaporator and each heating-side heat exchanger functioning as a condenser is determined by the amount of heat obtained from the waste heat recovery means of the driving engine. To make the evaporation temperature constant. As the waste heat recovery means, for example, an auxiliary heat exchanger that heats the refrigerant by exchanging heat between the refrigerant and the driving engine cooling water is provided, and by controlling an amount of the engine cooling water flowing through the auxiliary heat exchanger. The amount of heating of the refrigerant in the auxiliary heat exchanger can be controlled. Also, a plurality of such auxiliary heat exchangers are provided with different capacities, and the engine cooling water flow path or the refrigerant flow path of each auxiliary heat exchanger is selectively opened / closed, so that the total heat amount of the refrigerant in the auxiliary heat exchanger. May be controlled.

According to the second aspect of the present invention, when the cooling operation is mainly performed, of the heat exchangers of the indoor unit, each of the cooling-side heat exchanger functioning as an evaporator and the heating side functioning as a condenser. The capacity difference with each heat exchanger is compensated for by disposing the cooling water radiator of the driving engine close to the air cooling heat exchanger of the outdoor unit to suppress the heat radiation effect of the air cooling heat exchanger. The suppression of this heat dissipation effect
For example, the air-cooling heat exchanger of the outdoor unit is divided into at least two, and the radiators for the cooling water of the driving engine are also divided into the same number, and the radiators are arranged in proximity to the respective air-cooling heat exchangers, and the refrigerant of each air-cooling heat exchanger is provided. The flow can be controlled by selectively opening and closing the flow path, and by generating cooling air flowing from the radiator to the air-cooled heat exchanger to control the amount of air flow, or a combination of both.

[0007]

[Function] The capacity difference between each heat exchanger on the cooling side and each heat exchanger on the heating side of the indoor unit must be compensated for by heat exchange in the outdoor unit. When the heating mainly operates, the outdoor unit functions as an evaporator. However, it is necessary to provide a heat amount corresponding to the above-mentioned capacity difference. In the first invention, this heat amount is obtained from the waste heat recovery means of the driving engine, and the waste heat of the engine is effectively utilized. The amount of heat can be supplemented. In particular, since the auxiliary heat exchanger that heats the refrigerant with the cooling water of the driving engine acts as a small-capacity evaporator, it controls the amount of engine cooling water flowing through this auxiliary heat exchanger, or controls such an auxiliary heat exchanger. The heating amount is controlled by selectively opening and closing the engine cooling water passage or the refrigerant passage of each auxiliary heat exchanger to control the total heating amount of the refrigerant in the auxiliary heat exchanger. Appropriately controlled.

[0008] Further, the outdoor unit functions as a condenser during the cooling mainly operation, but the condenser function may be smaller than that in the cooling only. If the outdoor unit is large, the heating capacity is increased especially when the outside air temperature is low. It will be short. In the second invention, the radiator for the cooling water of the driving engine is arranged close to the air-cooled heat exchanger of the outdoor unit to suppress the heat radiation effect of the air-cooled heat exchanger, and the heat is effectively utilized by utilizing the waste heat of the engine. The effect can be suppressed. In particular, the heat exchanger of the outdoor unit is divided and the radiators for the cooling water of the drive engine are arranged close to each other, and the refrigerant flow path of each heat exchanger is selectively opened and closed, or from the radiator side to the heat exchanger side. By controlling the amount of the cooling air to flow and controlling the amount of the flowing air, it is possible to appropriately control the amount of suppression of the heat radiation action.

[0009]

FIGS. 1 and 2 schematically show a refrigerant circuit according to an embodiment of the first invention. 1 is an indoor unit, 2 is an outdoor unit, a high-pressure gas pipe 3, a liquid pipe 4
And a plurality of indoor units 1, 1...
It is connected to one outdoor unit 2 to constitute one system. The indoor unit 1 includes a heat exchanger 1a and an electronic expansion valve 1b, and the refrigerant flow is switched by a refrigerant branch controller 6 between cooling and heating. In the figure, three indoor units 1 are illustrated, and FIG. 1 shows a case where one unit on the left side is for cooling and the other two units are for heating, and the entire unit is in a heating-main operation state. One in the middle is heated, the other two
The case where the stand is cooled and the whole is in an operation state mainly of cooling is shown.

The outdoor unit 2 includes an engine 11 and a compressor 1
2 is a system for driving the air conditioner, 13 is an air-cooled first heat exchanger, 14 is an air-cooled second heat exchanger, 15 is an auxiliary heat exchanger, 16 is an electronic expansion valve, and 17 is an accumulator. ,
18 is a receiver, 19 is an exhaust heat exchanger of the engine 11,
20 is a radiator of the engine 11, 21 is a control unit, 22
Is a cooling water pump. In addition, solenoid valves are inserted at various points in the refrigerant circuit as shown. Auxiliary heat exchanger 1
Reference numeral 5 denotes a sub-evaporator for heating the refrigerant by the cooling water of the engine 11, and as shown in FIG.
Has a double-pipe structure in which an inner pipe 15b penetrates concentrically, for example, cooling water of about 80 ° C. is supplied to the outer pipe 15a, and heat exchange is performed with a refrigerant passing through the inner pipe 15b. Will be

The control unit 21 opens and closes each solenoid valve according to the cooling / heating capacity demand determined from the ON / OFF signals of the indoor units 1, 1... And the temperature of the engine cooling water as a heat source of the refrigerant. In addition to switching the path of the refrigerant flowing through the auxiliary heat exchanger 14 and the auxiliary heat exchanger 15 to make an optimal combination for controlling the heat exchange capacity, the engine 11, that is, the suction pressure and the discharge pressure of the compressor 12 are set to the optimal operation state. The number of rotations of the compressor 12 is controlled, and the frequency of the fans 13a and 14a of each heat exchanger and the opening of the electronic expansion valve 16 are controlled. The broken lines in FIGS. 1 and 2 illustrate signal lines, 25 is a temperature sensor for detecting the cooling water temperature of the engine 11, and 26 and 27 are the temperatures for detecting the refrigerant temperature at the inlet and the outlet of the auxiliary heat exchanger 15. Sensor, 28,
29 are pressure sensors for detecting the suction pressure and the discharge pressure of the compressor 12, respectively.

In FIGS. 1 and 2, the bold line indicates a circuit in which the refrigerant is flowing. In FIG. 1, which is mainly a heating operation, the heat exchangers 13 and 14 are not used, and only the auxiliary heat exchanger 15 has the refrigerant. In FIG. 2 in which the flow and cooling are mainly performed, the heat exchanger 1 is used.
3. Refrigerant flows through the path of the auxiliary heat exchanger 15 and the heat exchanger 14.

When the system is operated in the above configuration, the heat exchanger 1 of the indoor unit 1 in the cooling operation is operated.
a functions as an evaporator, and the heat exchanger 1a in the heating operation functions as a condenser. However, since their capacities are not the same, it is necessary to make up for the difference by some means.
In particular, when operating mainly in heating, it is necessary to provide the refrigerant with the heat amount having the above-described capacity difference. However, in the present invention, the outdoor unit 2 uses the waste heat of the driving engine to apply the heat amount corresponding to the above-described capacity difference to the refrigerant. In the embodiment, the auxiliary heat exchanger 15 exchanges heat between the refrigerant and the driving engine cooling water to heat the refrigerant.

That is, as shown in FIG. 1, for evaporating the liquid-phase refrigerant returning from the indoor unit 1 to the outdoor unit 2 via the liquid pipe 4,
Only the auxiliary heat exchanger 15 as shown in FIG. 3 is used without using the air-cooled heat exchangers 13 and 14, and the liquid-phase return refrigerant flows into the auxiliary heat exchanger 15 via the electronic expansion valve 16. , And evaporates into superheated steam and is sucked into the compressor 12. The refrigerant evaporation temperature is detected as the inlet temperature of the auxiliary heat exchanger 15, and by controlling the amount of engine cooling water flowing through the outer pipe 15a so that the evaporation temperature of the refrigerant flowing through the inner pipe 15b becomes a constant value, the cooling / cooling is performed. Maintain the optimal temperature that balances the warming ability.

FIG. 4 shows an example of the specific piping circuit.
Inverter 22 for driving cooling water pump 22 by control unit 21
By controlling a, the amount of engine cooling water flowing into the auxiliary heat exchanger 15 is controlled, and the heat exchange capacity of the auxiliary heat exchanger 15 is adjusted. Reference numeral 20a denotes a thermostat valve for automatically adjusting the amount of cooling water in the radiator 20 and the auxiliary heat exchanger 15.

In the mixed cooling / heating type operation, since the relationship between the air conditioning load of the outdoor unit and the heat radiation level of the engine cooling water is not constant, the cooling water in the conventional method in which the amount of bypass to the radiator is merely controlled by the thermostat valve is controlled. Although a sudden change in temperature or the like is likely to occur, when combined with the method using the auxiliary heat exchanger 15 as described above, the temperature of the cooling water is stabilized, and as a result, the stability of the refrigerant temperature is increased, and Control is performed. FIGS. 5 (a) to 5 (d) show the state of the cooling water pump rotation speed, the refrigerant superheat degree, the opening degree of the thermostat valve, and the cooling water temperature in the conventional system by broken lines and in the embodiment by solid lines. In the case of the embodiment, it is shown that the fluctuation of the refrigerant temperature or the like is reduced by controlling the rotation speed of the cooling water pump 22. (B)
In the superheat degree of the refrigerant in the drawing, the period indicated by A indicates the period in which the superheat degree is insufficient and the liquid back occurs.

The above is an embodiment corresponding to claim 2. FIGS. 6 and 7 show an embodiment corresponding to claim 3 in which a plurality of auxiliary heat exchangers having different capacities are provided. In FIG. 6, three auxiliary heat exchangers 1 having different capacities are used.
5-1, 15-2, and 15-3, an inner pipe is connected in series, a coolant is supplied to the inner pipe, and an engine cooling water is supplied to the outer pipe. As shown in FIG. 2B, the cooling water passages of the auxiliary heat exchangers are connected in parallel and a bypass passage 15-4 is further provided, and the solenoid valves 15-1a to 15-4a inserted into the cooling water passages are provided.
By selectively opening and closing the auxiliary heat exchanger 15-1
15-3 to control the total heating amount of the refrigerant.
In this case, the coolant channels are connected in parallel and the coolant channels are connected in series, and solenoid valves 15-1a to 15-3a are inserted into each coolant channel as shown in FIG. Can be selectively opened and closed.

FIG. 7 shows one auxiliary heat exchanger 15 in appearance.
However, the inner pipe 1 having a different thickness is provided inside the outer pipe 15a.
This is an example in which 5b and 15c are provided. In this case, the engine cooling water and the refrigerant may flow through either the outer pipe or the inner pipe. For example, as shown in FIG. 3C, the inner pipes 15b and 15c are connected in parallel and a bypass path 15d is provided. The engine cooling water flows through the solenoid valves 15B, 15C, and the solenoid valves 15B, 15C, respectively inserted into the inner pipes 15b, 15c and the bypass path 15d.
15D is selectively opened and closed. When the engine cooling water flows through the outer pipe 15a, for example, as shown in FIG. 3 (d), the inner pipes 15b and 15c are connected in parallel, the refrigerant flows through the pipes, and the solenoid valves inserted into the respective inner pipes are used. 15B and 15C are selectively opened and closed.

As described above, according to the first embodiment of the present invention, the amount of heat corresponding to the capacity difference of each indoor unit 1 during the operation mainly of heating is given from the waste heat of the engine, so that the auxiliary heat exchanger is used. By combining the control of the total heating amount of the refrigerant at 15 and the control of the electronic expansion valve 16, the heat exchange amount of the outdoor unit 2 can be finely controlled over a wide range.

[0020]

FIGS. 8 and 9 schematically show a refrigerant circuit according to a second embodiment of the present invention corresponding to claim 5, and FIG. FIG. 9 shows a cooling operation state in which all the indoor units 1 are in the cooling operation state in which the heating is in the cooling main operation state in which many other indoor units 1 are in the cooling state. . The present invention relates to control during the operation mainly of cooling, and the basic configuration is the same as that of FIG. 1 and the like, but the configurations of the air-cooled heat exchangers 13 and 14 are different, and the auxiliary heat exchanger 1
5 is not used. The same parts as those in FIG. 1 and the like are denoted by the same reference numerals.

FIG. 10 is a schematic structural view of the outdoor unit 2. The lower part of the outdoor unit 2 is an engine room 2A in which the engine 11 and the compressor 12 are arranged, and the upper part is a heat exchange room 2B. On both sides of the heat exchange chamber 2B, heat exchangers 13 and 14 which are provided in two parts are arranged, and the radiators 20a and 20b for cooling water which are further divided into two are respectively provided by the heat exchangers 13 and It is arranged in parallel immediately adjacent to the inside of 14. Fan 1 is provided on the upper surface of heat exchange chamber 2B.
3a and 14a are provided.
14a can rotate in both directions, and in the case of cooling operation, blows upward to generate an airflow like a white arrow,
During the cooling-main operation, air is blown downward to generate an airflow as indicated by a hatched arrow.

That is, the air flow heated by the radiators 20a and 20b impinges on the heat exchangers 13 and 14 during the cooling main operation, and the heat is radiated as compared with the cooling only when the outside air before the heating directly hits the heat exchangers 13 and 14. The effect is suppressed. The amount of heat radiation at this time can be determined by selectively opening and closing solenoid valves provided for each of the heat exchangers 13 and 14, and by using both heat exchangers 13 and 14 or using only one of them. By controlling the rotation speeds of the fans 13a and 14a to adjust the airflow generated in the direction of the hatched arrow in FIG. 10, it is possible to control finely and over a wide range. FIG. 8 shows the heat exchanger 1
3 shows a case where the refrigerant is flowing only in 3.

As described above, according to the second embodiment of the present invention, the cooling water radiators 20a and 20b arranged close to the heat exchangers 13 and 14 reduce the capacity difference between the indoor units 1 during the operation mainly of cooling. Is compensated by the heat dissipation suppression effect of
The heat exchange amount of the outdoor unit 2 can be finely controlled over a wide range without performing control for extremely reducing the rotation speed of the fan.

[0024]

As is apparent from the above description, the first aspect of the present invention is to recover the waste heat of the driving engine by using the capacity difference between the indoor unit performing the heating operation and the indoor unit performing the cooling operation during the operation mainly performed by heating. This is supplemented by the amount of heat obtained from the means. For this reason, the system configuration and control are different from those of the conventional system, in which the heat exchange amount of the air-cooled heat exchanger provided in the outdoor unit is controlled by adjusting the opening of the electronic expansion valve and the rotation speed of the compressor and the fan. Problems such as becoming very complicated or becoming susceptible to wind are eliminated, and the heating performance deteriorates in the conventional method due to frost generated in the air-cooled heat exchanger of the outdoor unit when the outside temperature is low. However, according to the present invention, since the waste heat recovery means is used, frost formation is irrelevant.

Therefore, according to the present invention, stable operation is performed over a wide control range according to the load of each indoor unit by effectively utilizing waste heat specific to the engine driven heat pump system, and both the cooling side and the heating side are used. It is possible to make full use of the capabilities of each indoor unit. In particular, by using an auxiliary heat exchanger that heats the refrigerant by exchanging heat between the refrigerant and the driving engine cooling water as waste heat recovery means, the amount of heat given to the refrigerant is appropriately controlled to achieve stable operation. Can be easily performed.

According to a second aspect of the present invention, a cooling water radiator of a driving engine disposed in close proximity to an air-cooling heat exchanger of an outdoor unit suppresses a heat radiating effect of the heat exchanger, thereby providing heating during a cooling mainly operation. This is to compensate for the difference in capacity between the indoor unit during operation and the indoor unit during cooling operation. Therefore, there is no problem in the conventional method, that is, there is no problem that the system configuration and control are very complicated and easily affected by wind, and the waste heat peculiar to the engine driven heat pump system is effectively utilized to make the air conditioner of the outdoor unit effective. This cancels out the capacity of the heat exchanger and enables stable operation over a wide control range.This also prevents the heating capacity from becoming insufficient during cooling-based operation at low outside temperatures. .

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a refrigerant circuit according to an embodiment of the first invention.

FIG. 2 is a schematic diagram of the same refrigerant circuit.

FIG. 3 is a diagram showing a configuration of an auxiliary heat exchanger of the embodiment.

FIG. 4 is a diagram showing a main part of the piping circuit of the embodiment.

FIG. 5 is a time chart showing a control state of the embodiment.

FIG. 6 is a side view and a piping circuit diagram showing another configuration of the auxiliary heat exchanger.

FIG. 7 is a side view, a sectional view, and a piping circuit diagram showing still another configuration of the auxiliary heat exchanger.

FIG. 8 is a schematic diagram of a refrigerant circuit in an embodiment of the second invention.

FIG. 9 is a schematic view of the refrigerant circuit.

FIG. 10 is a schematic side view showing the configuration of the outdoor unit of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Indoor unit 2 Outdoor unit 11 Engine 12 Compressor 13, 14 Air-cooling heat exchanger 13a, 14a Fan 15, 15-1, 15-2, 15-3 Auxiliary heat exchanger 20a, 20b Radiator 21 for cooling water 21 Control part

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F25B 27/02 F25B 29/00 361 F25B 27/00

Claims (5)

(57) [Claims] An engine-driven heat pump system capable of simultaneously operating a part of a plurality of indoor units for cooling and the rest for heating at the same time. The difference in capacity between each heat exchanger on the cooling side functioning as an evaporator and each heat exchanger on the heating side functioning as a condenser is given to the refrigerant from the waste heat recovery means of the driving engine. A cooling / heating mixed engine-driven heat pump system characterized in that the evaporation temperature of the refrigerant is compensated to be constant by the amount of heat applied. 2. An auxiliary heat exchanger for heating the refrigerant by exchanging heat between the refrigerant and the driving engine cooling water as the waste heat recovery means, and controlling the amount of engine cooling water of the auxiliary heat exchanger. 2. The heat pump system according to claim 1, wherein the heating amount of the refrigerant in the auxiliary heat exchanger is controlled. 3. A plurality of auxiliary heat exchangers having different capacities for heating the refrigerant by exchanging heat between the refrigerant and the engine cooling water for driving as the waste heat recovery means. 2. The cooling / heating mixed engine drive heat pump system according to claim 1, wherein a total heating amount of the refrigerant in the auxiliary heat exchanger is controlled by selectively opening and closing the engine cooling water flow path or the refrigerant flow path. 4. An engine-driven heat pump system capable of simultaneously operating a part of a plurality of indoor units for cooling and the rest for heating at the same time, wherein the heat exchanger of the indoor unit is mainly operated during cooling. Of these, the capacity difference between each heat exchanger on the cooling side functioning as an evaporator and each heat exchanger on the heating side functioning as a condenser is transferred to the air-cooled heat exchanger of the outdoor unit by the drive engine. A cooling / heating mixed engine-driven heat pump system characterized in that a cooling water radiator is arranged close to the air-cooling heat exchanger to suppress the heat radiation effect of the cooling water exchanger. 5. An air-cooling heat exchanger of the outdoor unit is divided into at least two, and a radiator for a cooling water of a driving engine is also divided into the same number, and a radiator is arranged close to each air-cooling heat exchanger. The amount of suppression of the heat radiation action by at least one of selectively opening and closing the refrigerant flow path of the cold heat exchanger and generating a cooling air flowing from the radiator side toward the air cooling heat exchanger and controlling the amount of the air flow. 5. The mixed cooling / heating type engine driven heat pump system according to claim 4, wherein: