JP2911253B2 - Refrigerant heating multi refrigeration cycle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerant heating type multi-refrigeration cycle provided with a refrigerant heater for heating a refrigerant during heating and a plurality of indoor heat exchangers.

[0002]

2. Description of the Related Art In a refrigeration cycle in an air conditioner for heating or cooling a room, heat absorbed by an outdoor heat exchanger serving as an evaporator at the time of heating is used as a heat source instead of using an atmospheric heat source. There is a refrigerant heating type.
The air conditioner of the refrigerant heating type has an advantage that the heating capacity is not influenced by the outside air temperature and can exhibit the heating capacity according to the amount of combustion as in the heat pump type using the heat source of the atmosphere.

[0003] Such a refrigerant-heated air conditioner has the following features.
As in the case of the heat pump type, a so-called single type in which one indoor heat exchanger and one outdoor heat exchanger are installed and connected by refrigerant pipes is generally used. A so-called multi-room air conditioner in which a plurality of indoor heat exchangers are provided for heating or cooling a plurality of rooms, for example, is widely used.

[0004] In a multi-room air conditioner, there is a case where a plurality of indoor heat exchangers are operated while changing the number of the operated indoor heat exchangers. For example, when one of the plurality of indoor heat exchangers is stopped for operation. There is a problem of where to store the excess refrigerant corresponding to the stopped indoor heat exchanger. That is,
The amount of refrigerant charged in the refrigeration cycle is usually set for multiple rooms, and when the number of operating units decreases, surplus refrigerant is generated.

[0005] The operating method when the number of operating units changes can be roughly classified into two types. One is when the refrigerant is not allowed to flow through the out-of-operation indoor heat exchanger, and the other is when the refrigerant is allowed to flow through the out of operation indoor heat exchanger.

[0006] In the former case, the proportional control valve (electronic expansion valve) on the liquid side, which is the refrigerant outflow side of the non-operating indoor heat exchanger, is fully closed to stop the flow of the refrigerant. The surplus refrigerant is stored in a refrigerant storage tank such as a liquid tank. Therefore, in this case, the piping configuration is complicated, such as providing a refrigerant storage tank, which leads to an increase in cost, and also involves a difficulty in a method for controlling the flow of refrigerant.

In the latter case, the opening degree of the liquid-side proportional control valve is controlled so that the refrigerant is condensed from the gas state and a certain degree of supercooling is obtained. In this case, the indoor fan of the operation-stop indoor heat exchanger is stopped, and the refrigerant is condensed by heat exchange with the heat of natural convection of the air flowing around the indoor heat exchanger. The opening of the valve is considerably reduced, and a small amount of refrigerant flows. Therefore, the control of the proportional control valve opening degree is extremely difficult, and when the throttle is too narrow, the refrigerant is accumulated in the indoor heat exchanger, and the amount of refrigerant on the indoor heat exchanger side in the operating state becomes too small, so-called a gas-out operation state. There is a problem that the air conditioner is liable to occur, and the sound of the refrigerant flowing through the non-operation indoor heat exchanger generates noise, which lowers the reliability of the air conditioner.

[0008]

As described above, in the conventional refrigerant-cooled multi-refrigeration cycle in a multi-chamber air conditioner, the number of operating indoor heat exchangers changes with the number of operating indoor heat exchangers. It is difficult to secure an appropriate refrigerant circulation amount corresponding to the above.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to ensure a proper amount of refrigerant circulation by simple control even when the number of operating indoor heat exchangers at the time of heating changes.

[0010]

In order to achieve the above object, the present invention provides a plurality of indoor heat exchangers connected in parallel for introducing high-temperature refrigerant discharged from a compressor during heating, and In a refrigerant heating type multi-refrigeration cycle having a refrigerant heater that heats refrigerant flowing out of the indoor heat exchanger and sends the refrigerant to the compressor, an on-off valve that can open and close both ends of a refrigerant passage of each indoor heat exchanger is provided. When there is an indoor heat exchanger that suspends its operation during the heating operation among the plurality of indoor heat exchangers,
Turn off the indoor fan of the heater and perform indoor heat exchange in other operating conditions.
When the supercooling degree of the heater reaches the set value,
Closing the on-off valve of the heat exchanger,
Is provided with control means for storing the refrigerant.

[0011]

When there is an indoor heat exchanger that suspends the operation during the heating operation among a plurality of indoor heat exchangers, the operation suspension room
Stop the indoor fan of the internal heat exchanger and
When the degree of subcooling of the internal heat exchanger has reached the set value, the on-off valves before and after the indoor heat exchanger in the idle state are closed. Thus, corresponding to the indoor heat exchanger dormant excess refrigerant <br/> accurately pooled in Ru results in its rest within the indoor heat exchanger, an indoor heat exchanger that other operation, proper Check the flow of refrigerant
As a result, an efficient operating state can be obtained. Ma
In addition, heat loss in the out-of-service indoor heat exchanger is reduced,
There is no sound of refrigerant flowing.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram of a refrigerant-heating type multi-refrigeration cycle showing an embodiment of the present invention. Main components are described in the order in which the refrigerant flows during heating (indicated by solid arrows). The compressor 1 compresses the refrigerant gas and discharges the refrigerant in a high-temperature, high-pressure state. A four-way switching valve 3 whose flow direction is switched, each of which has indoor fans 4a, 4b, 4c, and heats the refrigerant by the heat of combustion of three indoor heat exchangers 5a, 5b, 5c and a burner 7 connected in parallel with each other The refrigerant heater 9. Refrigerant heater 9
The two-way valve 11 provided on the upstream side of the flow of the refrigerant at the time of heating is opened at the time of heating and closed at the time of cooling. Further, the two-way valve 15 provided in the pipe 13 bypassing the indoor heat exchangers 5a, 5b, 5c opens when the heating capacity is small and closes when the heating capacity is large. At the time of cooling, the refrigerant flows as indicated by the dashed arrow, and the refrigerant discharged from the compressor 1 flows through the four-way switching valve 3 to the outdoor heat exchanger 19 having the outdoor fan 17, where it is cooled and condensed, And is led to the indoor heat exchangers 5a, 5b, 5c, and does not flow to the refrigerant heater 9.

The pipes 21a, 21b, 21c and 23a, 23 before and after the indoor heat exchangers 5a, 5b, 5c, respectively.
Gas side proportional control valves 25a, 25b, 25c and liquid side proportional control valves 27a, 27b, 27c are provided in the middle of the line connecting b, 23c and the outdoor unit 33, respectively.
The gas-side proportional control valves 25a, 25b, 25c and the liquid-side proportional control valves 27a, 27b, 27c together constitute on-off valves, and are controlled to be opened and closed by a control unit 29 as control means. Gas side proportional control valve 25a,
By controlling the opening and closing of 25b, 25c, the flow rate of the gas refrigerant flowing through each pipe 21a, 21b, 21c is controlled, and the individual heating capacity of each indoor heat exchanger 5a, 5b, 5c is controlled. On the other hand, the liquid side proportional control valve 27a,
27b and 27c control the degree of heating of the refrigerant heater 9 with the same opening. Generally, from the refrigerant outlet temperature of the refrigerant heater 9 (may be the refrigerant suction side temperature of the compressor 1),
The temperature difference obtained by subtracting the refrigerant inlet temperature of the refrigerant heater 9 is used as a pseudo heating degree, and the value is controlled so that the value becomes constant.

The control unit 29 suspends the operation of the plurality of indoor heat exchangers 5a, 5b, 5c during the heating operation. For example, when there is the indoor heat exchanger 5a, the control unit 29 is arranged before and after the indoor heat exchanger 5a. Gas side proportional control valve 25
a and the liquid side proportional control valve 27a are closed.

The gas-side proportional control valves 25a, 2 serving as flow dividers
5b, 25c and liquid side proportional control valves 27a, 27b, 27
and the like, the compressor 1, the refrigerant heat heater 9, the outdoor heat exchanger 19, etc., constitute an outdoor unit 33. Indoor unit 3
1 and the outdoor unit 33 are packed valves 35a, 35b, 3
5c. In addition, 37 is an accumulator, 39 is a strainer, 41 is a gas-liquid separator, 43, 4
5, 47 are capillary tubes, 49, 51, 53, 5
5 and 57 are check valves, and 59 is a high pressure switch.

Next, the operation during heating will be described.

When the heating operation is started based on a command from the indoor unit 31, a flame is formed in the burner 7 of the refrigerant heater 9 simultaneously with the start of the compressor 1, and the combustion heat is transferred to the refrigerant heater 9.
Heat exchange with the refrigerant flowing through the heat heat exchanger section. The vaporized refrigerant that has exchanged heat with the combustion heat in the refrigerant heater 9 is pressurized in the compressor 1, and is supplied with the four-way switching valve 3, the gas-side proportional control valves 25a, 25b,
After 25c, the air is guided to the indoor heat exchangers 5a, 5b, 5c, where it is air-cooled by the indoor fans 4a, 4b, 4c, and emits heat into the room to condense. The liquefied high-pressure refrigerant is slightly throttled by the liquid-side proportional control valves 27a, 27b, and 27c, enters the refrigerant heater 9, and is heated and vaporized again.

In the refrigeration cycle operated as described above, a plurality of gas-side proportional control valves 25a, 25b,
The opening degree of 25c is determined by the indoor heat exchangers 5a, 5b, 5 respectively.
c is controlled by the opening degree corresponding to the individual heating capacity. The method is, for example, a method obtained from the relationship between the valve opening degree and the capacity ratio,
Method for obtaining from the relationship between the condensation temperature ratio and the capacity ratio of the indoor heat exchangers 5a, 5b, 5c, the indoor heat exchangers 5a, 5b, 5c
From the relationship between the degree of supercooling and the capacity ratio. In addition, the opening degrees of the liquid side proportional control valves 27a, 27b, 27c are controlled such that the heating degree at the outlet of the refrigerant heater 9 is kept constant in the same state. Here, the role of the liquid side proportional control valves 27a, 27b, 27c is to control the flow rate of the refrigerant for controlling the degree of heating, and there is almost no role of the throttle as in the heat pump type refrigeration cycle.

FIG. 2 is an operation flowchart for controlling the degree of heating of the refrigerant heater 9 by the liquid side proportional control valves 27a, 27b, 27c in the heating capacity control. First, a command is output from the indoor unit 31 to output the required heating capacity obtained by summing all three indoor heat exchangers 5a, 5b, 5c.
(Step 201), the burner 7 outputs a combustion amount predetermined according to the required heating capacity (Step 203), and the compressor 1 is similarly operated at a predetermined frequency (Step 201). 205), heat is transmitted to the refrigerant.

Next, each liquid side proportional control valve 27a, 27b,
The refrigerant circulating amount is controlled at the same opening degree at 27c (step 2).
07), the heating degree of the refrigerant heater 9 is controlled. And
It is determined whether the heating degree is outside the set range (step 20).
9) When the value is out of the setting range, that is, the liquid-side proportional control valve 27
When it is difficult to control the heating degree at a, 27b, 27c,
The heating degree is controlled by changing the set frequency of the compressor 1 (step 211).

In such a heating operation, a case will be described in which one of the indoor heat exchangers 5a, 5b, 5c, for example, the indoor heat exchanger 5a is stopped. In this case, the gas-side proportional control valves 25a, 25b, 25c and the liquid-side proportional control valves 27a, 27b, 27c of the plurality of indoor heat exchangers 5a, 5b, 5c are all set to the same opening once, and this state Perform heating operation for a certain period of time. This is to condense the refrigerant flowing through the plurality of indoor heat exchangers 5a, 5b, 5c in substantially the same state. The condensed state differs depending on the air suction temperatures of the indoor heat exchangers 5a, 5b, 5c, and the indoor fans 4a, 4b, 4c
If the air suction temperature is low under the same air flow condition, the heating capacity increases accordingly, and the difference between the outlet temperature and the intermediate temperature in the indoor heat exchangers 5a, 5b, 5c, that is, the degree of supercooling, growing. For this reason, it is necessary to adjust the subcooling degree by reducing the airflow of the indoor fans 4a, 4b, 4c for the indoor heat exchangers 5a, 5b, 5c having a larger subcooling degree. As a result, the amount of refrigerant flowing through the indoor heat exchanger 5a in which operation is suspended and the amount of refrigerant flowing through the indoor heat exchangers 5b and 5c in other operation states are substantially the same, and are stored in the inactive indoor heat exchanger 5a. The amount of refrigerant to be used becomes appropriate.

As described above, the indoor heat exchangers 5a, 5b, 5c
It is ideal and desirable to suspend the operation of the indoor heat exchanger 5a with the same degree of supercooling from the viewpoint of storing an appropriate amount of refrigerant, but the refrigerant is brought into a gas state with the indoor fan 4a stopped. After flowing, the gas-side proportional control valve 25a and the liquid-side proportional control valve 27a may be closed to store the refrigerant. Of course, in this case, the amount of the refrigerant stored in the inactive indoor heat exchanger 5a is smaller than when the indoor fan is operated, but there is no possibility that the refrigerant flowing through the two operating indoor heat exchangers 5b and 5c is too much. .

FIG. 3 is a flowchart showing the control operation in this case. In this case, from the normal operation mode, the indoor fan 4a of the operation-stopped indoor heat exchanger 5a is stopped (Step 301), and the degree of supercooling Tu of the indoor heat exchangers 5b and 5c in the operation state is adjusted to the set value (Step 301). Step 303).
When the degree of supercooling Tu reaches the set value (step 30)
5), the gas side proportional control valve 2 before and after the inactive indoor heat exchanger 5a
5a and the liquid side proportional control valve 27a are both fully closed (step 307). The timing of closing the gas-side proportional control valve 25a and the liquid-side proportional control valve 27a may be performed when the time measured by the timer reaches a predetermined time.

As described above, when the operation of one of the indoor heat exchangers 5a, 5b, 5c, for example, the indoor heat exchanger 5a is stopped during the heating operation, the operation-stopped indoor heat exchanger 5a is Since the gas-side proportional control valve 25a and the liquid-side proportional control valve 27a before and after that are closed to store the refrigerant, it is necessary to provide a refrigerant storage tank such as a liquid tank for storing the surplus refrigerant corresponding to the idle indoor heat exchanger 5a. As a result, the complexity of the piping configuration and the excessive increase in cost are suppressed, and the difficulty of a method for controlling the flow of refrigerant in and out is eliminated.

Further, the amount of the refrigerant stored in the non-operation indoor heat exchanger 5a is an appropriate amount and does not excessively accumulate. Therefore, the amount of the refrigerant flowing through the other operating indoor heat exchangers 5b and 5c is not sufficient. The running out of gas is prevented without running out. Conversely, the amount of the refrigerant flowing through the indoor heat exchangers 5b and 5c does not become too large.

Further, in this case, the indoor heat exchanger 5 in operation stoppage is used.
Since the refrigerant is not stored in the internal heat exchanger 5a but remains stored, the air blowing mode by operating the indoor fan 4a can be used, and the heat loss in the non-operation indoor heat exchanger 5a is reduced.
There is an advantage that no sound of the refrigerant is generated.

It should be noted that the present invention is not limited to the above-described embodiment. For example, as in the case of a so-called ON-OFF operation without individual heating capacity ratio control in each indoor heat exchanger, a gas side proportional control valve is provided. Alternatively, the present invention can be applied to a case where a two-way valve is used. That is, in this case, the two-way valves corresponding to the respective indoor heat exchangers are fully opened for a certain period of time, the respective liquid-side proportional control valves are controlled at the same opening to control the heating degree of the refrigerant heater, and the indoor fan Adjust the degree of supercooling with the air volume.
After that, the two-way valve and the liquid side proportional control valve of the operation-stop indoor heat exchanger are fully closed, and the liquid side proportional control valve of the indoor heat exchanger in the operating state controls the heating degree of the refrigerant heater with the same opening. Do.

[0029]

As described above, according to the present invention, when an indoor heat exchanger that suspends the heating operation occurs among a plurality of indoor heat exchangers, the indoor heat exchanger before and after the indoor heat exchanger that suspends the operation is operated. The timing of closing the on-off valve is determined by other operating conditions.
When the degree of subcooling of the indoor heat exchanger reaches the set value
In order to perform this operation, the excess refrigerant
It can be stored accurately. Therefore, other driving
Indoor heat exchangers ensure adequate refrigerant flow.
As a result, an efficient operating state can be obtained. In addition, the non-operation indoor heat exchanger is in a storage state where the flow of refrigerant has stopped reliably.
Because the heat release loss is reduced, it does not occur sound of the flow of the refrigerant. Further, there is no need to provide a refrigerant storage tank such as a liquid tank for storing the surplus refrigerant corresponding to the non-operating indoor heat exchanger, which complicates the piping configuration,
Further, an excessive increase in cost is suppressed, and difficulties such as a method for controlling the flow of refrigerant in and out are eliminated.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a refrigeration cycle showing one embodiment of the present invention.

FIG. 2 is a flowchart of heating degree control in the refrigeration cycle of FIG.

FIG. 3 is a control flowchart in a case where an indoor heat exchanger whose operation is suspended occurs in the refrigeration cycle of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 5a, 5b, 5c Indoor heat exchanger 9 Refrigerant heater 25a, 25b, 25c On-off valve (gas side proportional control) 27a, 27b, 27c On-off valve (liquid side proportional control) 29 Control unit (control means)

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kazuo Saito 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Pref. Toshiba Corporation Living Space Systems Research Laboratory (56) References JP-A-63-91465 (JP, A) 58-88571 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F25B 13/00 104 F25B 13/00 341

Claims (1)

(57) [Claims] 1. A plurality of indoor heat exchangers connected in parallel to introduce a high-temperature refrigerant discharged from a compressor during heating, and the compressor which heats refrigerant flowing out of each of the indoor heat exchangers to heat the refrigerant. In the refrigerant heating type multi-refrigeration cycle having a refrigerant heater that feeds into the indoor heat exchanger, an open / close valve that can open and close both ends of the refrigerant passage of each of the indoor heat exchangers is provided, and the heating operation among the plurality of indoor heat exchangers is performed. If there is an indoor heat exchanger that suspends its operation,
Turn off the indoor fan of the heater and perform indoor heat exchange in other operating conditions.
When the supercooling degree of the heater reaches the set value,
Closing the on-off valve of the heat exchanger,
A refrigerant heating type multi-refrigeration cycle, characterized in that a control means for storing a refrigerant is provided.