JP2008298379A - Reheat type air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately adjust blow-out temperature and humidity while maintaining a stable circulation cycle. <P>SOLUTION: A first bypass pipe 10 for bypassing an outdoor heat exchanger 4 is connected to a circulation circuit of a reheat type air conditioner. A first bypass valve 11 capable of adjusting a flow rate of a refrigerant inside the first bypass pipe 10 is provided in the first bypass pipe 10. By changing a flow rate of a refrigerant flowing to the outdoor heat exchanger 4 side by the first bypass valve 11, reheat amount with respect to indoor air can be adjusted by a reheat heat exchanger 6. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a reheat type air conditioner employing a heat pump system.

As a reheat type air conditioner, a compressor, an outdoor heat exchanger, a reheat heat exchanger, a decompressor, and an indoor heat exchanger are connected by piping to form a circulation circuit in which a refrigerant is enclosed. Let's maintain indoor comfort by increasing the blowing temperature by performing dehumidifying operation that reheats the indoor air cooled by heat exchange with refrigerant in the indoor heat exchanger and blows it out to the room The configuration is well known. However, in this case, there is a problem that the amount of reheating is not stable due to external conditions such as air temperature, and the adjustment of the blowing temperature and humidity cannot be performed sufficiently.
Therefore, in the air conditioner disclosed in Patent Document 1, an adjustment valve is provided between the discharge side of the compressor of the indoor unit and the outdoor throttle valve and the reheat heat exchanger, and the compressor discharges during the dehumidifying operation. A bypass passage that guides the refrigerant to the reheat heat exchanger is connected. That is, during the dehumidifying operation, the control valve of the bypass passage is controlled to be fully opened, and the refrigerant pressure reduction degree of the outdoor throttle valve is controlled based on the indoor temperature, thereby expanding the control range of the indoor air and reheating heat. The air temperature blown into the room from the exchanger can be set to a cooling or heating atmosphere.

JP 2003-28537 A

  In the reheat-type air conditioner of Patent Document 1, two valves are used: an outdoor throttle valve that is a heat source side throttle mechanism with a variable refrigerant pressure reduction degree, and an adjustment valve that is a flow rate adjustment mechanism that adjusts the refrigerant flow rate. It creates a mixed state at the reheat heat exchanger inlet. However, if the discharge pressure of the compressor changes depending on the outside air conditions, the condensation temperature also changes, so if you try to mix the refrigerant flow rate bypassed to the reheat heat exchanger and the refrigerant flow rate after passing through the outdoor heat exchanger at the same ratio It is necessary to change the opening ratio of the two valves each time. Therefore, there are two parameters (opening of the outdoor throttle valve and the regulating valve) for one target value of the inlet temperature of the reheat heat exchanger, and it is difficult to create a stable state. The cost was high due to the need for advanced control technology.

  Therefore, an object of the present invention is to provide a reheat type air conditioner that can control the temperature and humidity of a blowout easily and reliably.

In order to achieve the above object, according to the first aspect of the present invention, a bypass pipe that bypasses the outdoor heat exchanger is connected to the circulation circuit, and the flow rate of the refrigerant in the bypass pipe can be adjusted to the bypass pipe. A flow rate adjusting means is provided, and the flow rate of the refrigerant flowing to the outdoor heat exchanger side is changed by the flow rate adjusting means, so that the amount of reheating of the indoor air by the reheat heat exchanger can be adjusted. Is.
In addition to the object of claim 1, the invention described in claim 2 is provided with a second bypass pipe that bypasses the reheat heat exchanger in the circulation circuit in order to suppress excessive reheating by the reheat heat exchanger. Connected to the second bypass pipe is provided with a second flow rate adjusting means capable of adjusting the flow rate of the refrigerant in the second bypass pipe, and the flow rate of the refrigerant flowing toward the reheat heat exchanger is changed by the second flow rate adjusting means. It is characterized by being possible.

According to the first aspect of the present invention, the use of the bypass pipe bypassing the outdoor heat exchanger and the flow rate adjusting means simplifies the apparatus and does not cost. In addition, the temperature and humidity of the blowout air can be controlled easily and reliably.
According to the second aspect of the present invention, in addition to the effect of the first aspect, the adoption of the second bypass pipe that bypasses the reheat heat exchanger and the second flow rate adjusting means can cause an excessive amount due to the reheat heat exchanger. It is possible to more suitably adjust the blowing temperature and humidity while suppressing reheating. In particular, with respect to one target value, the second flow rate adjustment means can increase the heating amount only up to the amount of supercooling, but the heating amount is further increased by the flow rate control means. Humidity can be controlled.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a circuit diagram showing an example of a reheat type air conditioner according to the present invention. In the figure, 1 is an outdoor unit, 2 is an indoor unit, and the reheat type air conditioner is connected to the outdoor unit 1 with a compressor 3. And an outdoor heat exchanger 4, an indoor heat exchanger 5 and a reheat heat exchanger 6 are arranged in the indoor unit 2, these are connected by a pipe 7, and a circulation circuit in which the enclosed refrigerant circulates is provided. Formed.
In the outdoor unit 1, an accumulator 8 is provided on the suction side of the compressor 3, and a four-way valve 9 is provided between the compressor 3 and the outdoor heat exchanger 4, and the refrigerant flow is exchanged with the outdoor heat. It is possible to switch between the unit 4 side and the indoor unit 2 side.
Moreover, the 1st bypass pipe 10 which bypasses the outdoor heat exchanger 4 is connected to the piping 7 in the outdoor unit 1, and the 1st bypass pipe 10 is connected by the 1st bypass valve 11 as a flow volume adjustment means provided here. The flow rate of the flowing refrigerant can be adjusted. 12 is an outdoor unit fan provided in the outdoor heat exchanger 4, 13 is a heating expansion valve that depressurizes the refrigerant during heating by a one-way valve, and 14 is a heating receiver that stores the refrigerant during heating.

On the other hand, in the indoor unit 2, a cooling expansion valve 15 is provided between the indoor heat exchanger 5 and the reheat heat exchanger 6 as a decompressor that decompresses the refrigerant during cooling by a one-way valve. Is provided with a second bypass pipe 16 that bypasses the reheat heat exchanger 6, and the flow rate of the refrigerant flowing through the second bypass pipe 16 as the second flow rate adjusting means can be adjusted in the second bypass pipe 16. A second bypass valve 17 is provided.
Reference numeral 18 denotes an indoor unit fan, and the indoor unit fan 18 can be driven to blow out indoor air that has passed through the indoor heat exchanger 5 and the reheat heat exchanger 6 into the room. 19 is a cooling receiver that is connected to a pipe on the cooling expansion valve 15 side and stores the refrigerant during cooling, and 20 is provided in a pipe between the outdoor unit 1 and the indoor unit 2 to visually check the state of the refrigerant. For sight glass.

In the reheat type air conditioner configured as described above, the switching control of the four-way valve 9 is performed by a controller (not shown) during each of the cooling (dehumidification) and heating operations, and the first and second bypass valves 11 and 17 are controlled. Opening and closing and opening control are performed.
First, during cooling (dehumidification) operation, the four-way valve 9 switches the discharge side of the compressor 3 to the outdoor heat exchanger 4 side and the suction side to the indoor unit 2 side, as shown by the solid line in FIG. Then, when the high-temperature and high-pressure refrigerant discharged from the compressor 3 passes through the outdoor heat exchanger 4 serving as a condenser, it dissipates heat and condenses by heat exchange with the outside air, and the reheat heat exchanger of the indoor unit 2 After passing through 6 and depressurizing by the cooling expansion valve 15 to lower the temperature, it is gasified by the indoor heat exchanger 5 and sent again to the compressor 3 via the four-way valve 9, and this circulation is repeated. Therefore, when indoor air passes through the indoor heat exchanger 5, it is cooled and blown out by heat exchange with the low-temperature refrigerant, but by heat exchange with the refrigerant when passing through the reheat heat exchanger 6. Because it is reheated. A drop in the blowing temperature can be suppressed.

However, if the blowing temperature is low even after heat exchange with the reheat heat exchanger 6, the first bypass valve 11 is opened. Then, the flow rate of the refrigerant to the outdoor heat exchanger 4 side is reduced and the heat exchange rate is lowered, and the refrigerant liquefied after passing through the outdoor heat exchanger 4 is in a gas state flowing through the first bypass pipe 10 side. It is mixed with the refrigerant and sent to the reheat heat exchanger 6. Therefore, when heat is exchanged by the reheat heat exchanger 6, the blowing temperature can be increased.
On the contrary, when the blowing temperature becomes too high due to heat exchange with the reheat heat exchanger 6, the second bypass valve 17 is opened. Then, since the flow rate of the refrigerant to the reheat heat exchanger 6 is reduced and the heat exchange rate is lowered, the blowing temperature can be lowered.
That is, the controller detects the blowing temperature with a temperature sensor (not shown) and monitors the temperature. If the blowing temperature falls below or exceeds a predetermined temperature, the first and second bypass valves 11 and 17 are opened at a predetermined opening degree. By opening the valve, the amount of reheating by the reheat heat exchanger 6 can be appropriately maintained.

On the other hand, during heating operation, as shown by a dotted line in FIG. 1, the four-way valve 9 switches the discharge side of the compressor 3 to the indoor unit 2 side and the suction side to the outdoor heat exchanger 4 side. The first and second bypass valves 11 and 17 are always closed.
Therefore, after the high-temperature and high-pressure refrigerant discharged from the compressor 3 passes through the indoor heat exchanger 5 and the reheat heat exchanger 6 serving as a condenser and dissipates heat by heat exchange with room air, the heating receiver 14 And is decompressed by the heating expansion valve 13 and passes through the outdoor heat exchanger 4 serving as an evaporator, so that it is changed from a liquid gas state to a gas state by heat exchange with the outside air and sent to the compressor 3 again. . This circulation is repeated. Accordingly, the indoor air is warmed by the indoor heat exchanger 5 and the reheat heat exchanger 6 and blown out into the room.

Thus, according to the reheat type air conditioning apparatus of the said form, the 1st bypass pipe 10 which bypasses the outdoor heat exchanger 4 is connected to a circulation circuit, The 1st bypass pipe is connected to the 1st bypass pipe 10 The first bypass valve 11 capable of adjusting the flow rate of the refrigerant in the interior 10 is provided, and the flow rate of the refrigerant flowing to the outdoor heat exchanger 4 side is changed by the first bypass valve 11 so that the room by the reheat heat exchanger 6 can be changed. By making it possible to adjust the amount of reheating to air, it is possible to control the temperature and humidity of the blowout easily and reliably. Moreover, since the apparatus is simplified, no cost is incurred.
In particular, here, a second bypass pipe 16 that bypasses the reheat heat exchanger 6 is connected to the circulation circuit, and the second bypass pipe 16 can adjust the flow rate of the refrigerant in the second bypass pipe 16. By providing a bypass valve 17 and allowing the flow rate of the refrigerant flowing to the reheat heat exchanger 6 side to be changed by the second bypass valve 17, excessive reheating by the reheat heat exchanger 6 is suppressed, and the blowing temperature and humidity It is possible to make a more suitable adjustment. In particular, with respect to one target value, the second bypass valve 17 can only increase the amount of heating up to the amount of supercooling, but since the amount of heating is further increased by the first bypass valve 11, the control value becomes one and is stable. The blowout temperature and humidity can be controlled.

Here, the change in the blowing temperature due to the use of only the first bypass pipe was verified.
With the second bypass valve closed under the outdoor air conditions of dry bulb temperature 35.0 ° C and wet bulb temperature 24.0 ° C, and indoor conditions of dry bulb temperature 27.0 ° C and wet bulb temperature 17.8 ° C The opening degree of the first bypass valve was changed stepwise from 0% to 10%, 25%, 50%, and 75% to confirm the change in reheating capacity. FIG. 2 is a graph showing the relationship between the opening degree of the first bypass valve and the blowing temperature in that case, where the solid line a is the blowing temperature (dry bulb temperature) through the reheat heat exchanger, and the dotted line b is the indoor heat exchanger. The blowing temperature (dry bulb temperature) after passing through is shown respectively.
As is clear from the above, in a, the blowing temperature rises in the range of 0 to 25% of the opening degree of the first bypass valve, and the flow rate of the refrigerant flowing to the outdoor heat exchanger side is changed by the first bypass valve. Thus, it was confirmed that the reheating amount by the reheat heat exchanger can be adjusted. The reason that the blowing temperature is substantially constant after 25% is that the refrigerant flow rate of the first bypass pipe is maximized at the opening degree of 25%.

[Reference example]
Next, as a reference example, the change in the blowing temperature due to the use of only the second bypass pipe was verified.
Under the same outside air conditions and indoor conditions as in the first embodiment, with the first bypass valve closed, the opening degree of the second bypass valve is stepwise from 0% to 10%, 25%, 50%, and 75%. The change in reheating ability was confirmed by changing. FIG. 3 is a graph showing the relationship between the opening degree of the second bypass valve and the blowing temperature in that case, where the solid line a is the blowing temperature (dry bulb temperature) passing through the reheat heat exchanger, and the dotted line b is the indoor heat exchanger. The blowing temperature (dry bulb temperature) after passing through is shown respectively. Here, if the opening degree of the second bypass valve is increased, the refrigerant flow rate to the reheat heat exchanger decreases, so the heat exchange rate in the reheat heat exchanger decreases, the pipe temperature decreases, and the reheat is performed. It can be seen that the amount is reduced.

Next, the change in the blowing temperature due to the combined use of the first and second bypass pipes was verified.
While the opening degree of the second bypass valve is changed from 0% to 50% with the opening degree of the first bypass valve being 25% under the same outside air conditions and indoor conditions as in Examples 1 and 2, the first bypass With the valve opening being 50%, the opening of the second bypass valve was changed from 0% to 50%. FIG. 4 is a graph showing the relationship between the opening degree of the first and second bypass valves and the blowing temperature in that case. When (A) is 25% of the opening degree of the first bypass valve, (B) is the opening degree. In each case, the solid line a indicates the blowing temperature (dry bulb temperature) passing through the reheat heat exchanger, and the dotted line b indicates the blowing temperature (dry bulb temperature) passing through the indoor heat exchanger. Here, the blowing temperature decreases by increasing the opening of the second bypass valve (from 20.83 ° C. to 11.92 ° C. in (A) and from 21.05 ° C. to 12.05 ° C. in (B), respectively. It can be seen that excessive reheating is suppressed.

In addition, although the said form demonstrated in the example which used the 1st bypass pipe and the 1st bypass valve, the 2nd bypass pipe, and the 2nd bypass valve together, the 2nd bypass pipe and the 2nd bypass valve were lost. It is also possible to adjust the reheating amount in the reheat heat exchanger with only the first bypass pipe and the first bypass valve.
The flow rate control means uses a bypass valve (electromagnetic valve) that is electrically opened and closed by the controller in the above embodiment, but includes a type that manually adjusts the opening degree.
Furthermore, although the reheat-type air conditioner that performs the heating operation is described here, the cooling (dehumidification) operation alone may be used. In this case, a four-way valve, a heating expansion valve, and the like can be omitted. Of course, the receiver and the sight glass can be omitted.

It is a circuit diagram of a reheat type air harmony device. It is a graph which shows the relationship between the opening degree of a 1st bypass valve, and blowing temperature. It is a graph which shows the relationship between the opening degree of a 2nd bypass valve, and blowing temperature. It is a graph which shows the relationship between the opening degree of a 1st, 2nd bypass valve, and blowing temperature.

Explanation of symbols

  1 .... Outdoor unit 2 .... Indoor unit 3 .... Compressor 4 .... Outdoor heat exchanger 5, ... Indoor heat exchanger 6, ... Reheat heat exchanger, 7 .... Piping, 9 .... · Four-way valve, 10 · · 1st bypass pipe, 11 · · 1st bypass valve, 12 · · Outdoor fan, 13 · · Expansion valve for heating, 15 · · Expansion valve for cooling, 16 · · 2nd bypass tube 17, second bypass valve, 18 ... indoor unit fan.

Claims (2)

A compressor, an outdoor heat exchanger, a reheat heat exchanger, a decompressor, and an indoor heat exchanger are connected by piping to form a circulation circuit that encloses the refrigerant, and the indoor heat exchanger A reheat-type air conditioner that performs at least a dehumidifying operation in which heat-exchanged room air is reheated by the reheat heat exchanger and blown into the room,
A bypass pipe that bypasses the outdoor heat exchanger is connected to the circulation circuit, and a flow rate adjusting means capable of adjusting a flow rate of the refrigerant in the bypass pipe is provided in the bypass pipe, and the outdoor heat is adjusted by the flow rate adjusting means. A reheat type air conditioner characterized in that the amount of reheat to the indoor air by the reheat heat exchanger can be adjusted by changing the flow rate of the refrigerant flowing to the exchanger side.   A second bypass pipe that bypasses the reheat heat exchanger is connected to the circulation circuit, and the second bypass pipe is provided with second flow rate adjusting means capable of adjusting the flow rate of the refrigerant in the second bypass pipe, The reheat type air conditioner according to claim 1, wherein the flow rate of the refrigerant flowing to the reheat heat exchanger side can be changed by the second flow rate adjusting means.

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