JP3040141B2 - Air conditioner - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an air conditioner provided with a refrigerant heating device.

2. Description of the Related Art As an air conditioner equipped with a conventional refrigerant heating device, for example, an air conditioner configured as shown in FIG. 3 is known. Hereinafter, a description will be given based on the drawings. The compressor 1, the four-way valve 2, the indoor heat exchanger 3, the pressure reducer 4, the first check valve 5, the outdoor heat exchanger 6, and the second check valve 7 are connected in a ring shape. A refrigerant heating device 9 is connected between the indoor heat exchanger 3 and the pressure reducer 4 to the suction side of the compressor 1 via a two-way valve 8. Also,
As a refrigerant circulation amount adjusting mechanism, the discharge side and the suction side of the compressor 1 are connected by a bypass circuit via an expansion valve 10.

Therefore, at the time of cooling, the four-way valve 2 is switched to the cooling side, the two-way valve 8 is closed, the expansion valve 10 is fully closed, and the compressor 1 is operated.
Accordingly, the refrigerant flows as indicated by the dotted arrow in FIG. 3, is condensed in the outdoor heat exchanger 6, evaporates in the indoor heat exchanger 3, and cools the room.

Next, at the time of heating, the four-way valve 2 is switched to the heating side, and the two-way valve 8 is turned on.
Is closed, the expansion valve 10 is fully closed, the compressor 1 is operated for a certain period of time, and a refrigerant recovery operation for recovering the refrigerant accumulated in the outdoor heat exchanger 6 to the indoor heat exchanger 3 is performed. Open, the room temperature is detected by the indoor temperature detection thermistor 11 of the indoor unit 13, and the difference between the set temperature and the room temperature indicates the heating amount determined by the heating load as shown in the heating amount characteristic diagram of the refrigerant heating device in FIG. The refrigerant heating device 9 is operated. Here, the heating amount is represented by% with the maximum heating amount as 100%. Further, the refrigerant temperature is detected by the refrigerant temperature thermistor 12 of the outdoor unit 14, and the opening degree of the expansion valve 10 is controlled by controlling the opening degree of the expansion valve 10 so that the refrigerant is not overheated and deteriorated or liquid back to the compressor 1 does not occur. The amount of circulation is adjusted. Therefore, the refrigerant flows as indicated by the solid arrow in FIG. 3, evaporates in the heat exchanger 9a of the refrigerant heating device 9, condenses in the indoor heat exchanger 3, and heats the room. Here, the changing speed when changing the heating amount of the refrigerant heating device 9 is always constant except during ignition and extinguishing. 9b is a burner.

Problems to be Solved by the Invention However, the air conditioner provided with the conventional refrigerant heating device as described above has the following problems.

In the heating operation, when the heating amount or the refrigerant circulation amount is changed according to the change in the heating load, and the refrigerant circulation amount or the heating amount is controlled by the refrigerant temperature in accordance with the change, the heat capacity or the transfer capacity of the heat exchanger 9a of the refrigerant heating device 9 is controlled. Due to the heat speed, changing the heating amount or the refrigerant circulation amount does not immediately change the refrigerant temperature. Also,
The change rate of the refrigerant circulation amount is slower than the heating amount, and it takes time to stabilize. Therefore, a time lag occurs between the change in the amount of heating and the amount of circulating refrigerant, and a state in which the amount of heating is temporarily excessively large or small with respect to the amount of refrigerant circulating occurs.
The refrigerant temperature transiently overshoots, and then becomes stable. Therefore, the refrigerant may be temporarily heated to deteriorate the refrigerant, or the liquid may flow back to the compressor 1 to shorten the life of the compressor 1.

This transient characteristic can be improved to some extent by reducing the rate of change of the heating amount. However, the overshoot is larger when the heating amount is increased than when it is reduced, and the overshoot is larger when the heating amount is larger than when the change width is small. Therefore, the optimal change rate of the heating amount is slower when increasing the heating amount than when decreasing the heating amount, and slower when increasing the change width is smaller, and the changing speed of the heating amount is the slowest. It is necessary to match. However, if the change speed is too slow, the ability to follow the heating load is deteriorated, and merely reducing the change speed does not provide a sufficient measure.

The present invention has been made in view of the above points, and has as its object to prevent the refrigerant from overshooting and the refrigerant from being overheated and deteriorated.

Means for Solving the Problems In order to solve the above problems, the present invention provides a heating operation, when changing the heating amount in the refrigerant heating device, when the change width of the heating amount is larger than when the change width is smaller, the heating is It slows down the rate of change of the quantity.

Further, the present invention, when increasing the heating amount of the refrigerant heating device during the heating operation, the refrigerant circulation amount by the refrigerant circulation amount adjustment mechanism,
When the heating amount is temporarily increased from a predetermined refrigerant circulation amount determined in advance, and the heating amount is decreased, the refrigerant circulation amount is adjusted by the refrigerant circulation amount adjustment mechanism, and the predetermined refrigerant circulation amount is determined in advance from the heating amount. The amount is temporarily reduced from the amount.

Operation The operation of the above means is as follows.

In the heating operation, when the heating amount is changed by the refrigerant heating device during heating operation, the case where the change width of the heating amount is smaller is larger than the case where the change amount of the heating amount is smaller. It is possible to select the speed, and when the heating amount is significantly changed, the refrigerant transiently overshoots, causing overheating of the refrigerant and liquid back to the compressor, causing deterioration of the refrigerant and the life of the compressor Can be prevented from being shortened without impairing the followability to the heating load when the change width of the heating amount is small.

Further, the present invention, when increasing the heating amount of the refrigerant heating device during the heating operation, the refrigerant circulation amount by the refrigerant circulation amount adjustment mechanism, temporarily increasing from the heating amount to a predetermined refrigerant circulation amount predetermined in advance. When the heating amount is reduced, the refrigerant circulation amount is temporarily reduced from the heating amount to a predetermined refrigerant circulation amount by the refrigerant circulation amount adjusting mechanism, thereby changing the refrigerant circulation amount with respect to the heating amount. When the amount of heating is changed, the refrigerant transiently overshoots, causing overheating of the refrigerant and liquid back to the compressor, resulting in deterioration of the refrigerant and shortening the life of the compressor. Can be prevented.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, a first embodiment of the present invention will be described. Control of refrigeration cycle and cooling operation, refrigerant recovery operation at the start of heating operation, compressor, four-way valve during heating operation,
The control of the two-way valve and the expansion valve is the same as that of the conventional example, and the description is omitted.

In the control of the heating amount of the refrigerant heating amount device, the relationship between the heating load and the heating amount is the same as in the conventional example, but in the present embodiment, the changing speed of the heating amount is determined as shown in FIG. That is, when the change width of the heating amount is small, the change speed is made slower when the change width is large, so that the change speed in each change width is optimized. Here, the change speed and the change width are expressed in percentage with respect to the maximum heating amount as 100%.

Therefore, when the heating amount is significantly changed, the transient overshoot of the refrigerant causes overheating of the refrigerant and liquid back to the compressor, which causes deterioration of the refrigerant and shortens the life of the compressor. When the change width is small, it can be prevented without impairing the ability to follow the heating load. Further, when changing the refrigerant heating amount, the same effect can be obtained by changing the refrigerant heating amount in a stepwise manner, as in a case where the changing speed of the refrigerant heating amount is artificially reduced.

Next, a second embodiment of the present invention will be described. The control of the refrigeration cycle and the cooling operation, the refrigerant recovery operation at the start of the heating operation, and the control of the compressor, the four-way valve, and the two-way valve at the time of the heating operation are the same as those in the above-described conventional example, and will not be described.

In the present embodiment, when the heating amount of the refrigerant heating device is changed, the opening degree of the expansion valve is changed by the shift amount shown in the expansion valve opening degree shift characteristic diagram of FIG. When the heating amount is increased, the opening amount is increased, and when the heating amount is decreased, the opening amount is decreased. Here, the opening shift amount is expressed as a percentage with respect to the proportional valve opening when the maximum heating amount is taken as 100%.

Therefore, when changing the heating amount, it is possible to prevent the refrigerant from overheating and the liquid back to the compressor due to the transient overshoot of the refrigerant, thereby preventing the refrigerant from deteriorating and shortening the life of the compressor. it can.

Here, even when the refrigerant circulation amount is controlled by another method such as changing the capacity of the compressor, the refrigerant circulation amount may be temporarily increased or decreased when the heating amount is increased or decreased in the same manner as in the present embodiment. Can obtain the same effect.

It is needless to say that a higher effect can be obtained by combining the first and second embodiments.

Advantageous Effects of the Invention As described above, according to the present invention, during the heating operation, when the heating amount is changed by the refrigerant heating device, the case where the change width of the heating amount is smaller is larger than the case where the heating amount changing speed is larger. By slowing down, it is possible to select the optimum change speed for each, and when changing the heating amount significantly, the refrigerant transiently overshoots, causing overheating of the refrigerant and liquid back to the compressor Deterioration of the refrigerant and shortening of the life of the compressor can be prevented without impairing the followability to the heating load when the change width of the heating amount is small.

Further, the present invention, when increasing the heating amount of the refrigerant heating device during the heating operation, the refrigerant circulation amount by the refrigerant circulation amount adjustment mechanism,
When the heating amount is temporarily increased from a predetermined refrigerant circulation amount determined in advance, and the heating amount is decreased, the refrigerant circulation amount is adjusted by the refrigerant circulation amount adjustment mechanism, and the predetermined refrigerant circulation amount is determined in advance from the heating amount. By temporarily reducing the amount of refrigerant, it compensates for the delay in the change of the amount of refrigerant circulating with respect to the amount of heating, and when changing the amount of heating, the refrigerant transiently overshoots, causing overheating of the refrigerant and liquid to the compressor. It is possible to prevent the occurrence of back and deterioration of the refrigerant and shortening of the life of the compressor.

[Brief description of the drawings]

FIG. 1 is a characteristic diagram of a heating amount changing speed of a refrigerant heating device according to one embodiment of the present invention, FIG. 2 is a characteristic diagram of an expansion valve opening shift in another embodiment of the present invention, and FIG. FIG. 4 is a refrigeration cycle diagram of the harmony machine, and FIG. 4 is a heating amount characteristic diagram of the refrigerant heating device in the conventional example.

Claims (2)

(57) [Claims] 1. A compressor, a four-way valve, an indoor heat exchanger, a pressure reducer,
When a refrigerant heating device that heats a refrigerant is provided in a part of a refrigeration cycle in which an outdoor heat exchanger or the like is connected in a ring shape, and when the heating amount is changed by the refrigerant heating device during a heating operation, a change width of the heating amount is small. An air conditioner with a larger heating rate changing speed is larger. 2. A compressor, a four-way valve, an indoor heat exchanger, a pressure reducer,
A case where a refrigerant heating device for heating refrigerant is provided in a part of a refrigeration cycle in which an outdoor heat exchanger or the like is connected in a ring shape, and a refrigerant circulation amount adjusting mechanism is further provided to increase a heating amount of the refrigerant heating device during a heating operation. The refrigerant circulating amount is temporarily increased from a heating amount by a predetermined refrigerant circulating amount by the refrigerant circulating amount adjusting mechanism, and when the heating amount is decreased, the refrigerant circulating amount is adjusted by the refrigerant circulating amount adjusting mechanism. An air conditioner wherein the amount is temporarily decreased from a heating amount to a predetermined circulation amount of a refrigerant.