JP2011097896A - Air conditioner intended for plastic greenhouse for horticultural farming - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioner intended for plastic greenhouses for horticultural farming, capable of making a uniform air conditioning for the temperature in a plastic greenhouse without reducing fanning levels in making a dehumidifying operation. <P>SOLUTION: The an air conditioner intended for plastic greenhouses for horticultural farming includes: a heat exchanger 14 for reheating use installed on the downstream side of the fanning channel of an in-greenhouse-side heat exchanger 9; a cooling medium circuit for reheating use functioning to introduce part of a gas cooling medium extruded from a compressor 4 into the heat exchanger 14 for reheating use and join the cooling medium liquefied by the heat exchanger 14 for reheating use into a cooling medium flow channel between an expansion valve 8 and the in-greenhouse-side heat exchanger 9; an expansion valve 15 for reheating use installed on the downstream side of the heat exchanger 14 for reheating use in the cooling medium circuit for reheating use and functioning to control a cooling medium level by the divergence of the heat exchanger 14 for reheating use; a temperature sensor 18 installed on the downstream side of the fanning channel of the heat exchanger 14 for reheating use and functioning to detect air temperature; and a control unit 3 functioning to variably control the divergence of the expansion valve 15 for reheating use so that the air temperature detected by the temperature sensor 18 comes to a preset target value in the case of conducting dehumidifying operation. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an air conditioner for a greenhouse for horticulture agriculture.

  In a greenhouse for horticulture agriculture, the room is cooled to a room temperature suitable for the cultivation in the house in the summer, and dehumidification is performed to prevent the cultivation in the house from pest damage at night and in the middle of the summer when no cooling is required. There is a need to do. As such an air conditioner for a greenhouse for horticultural agriculture, a general-purpose packaged air conditioner is generally used (see, for example, Patent Document 1). In the winter season, heating is performed by the general-purpose packaged air conditioner, and when heating capacity is required, heating is performed by a combustion system device.

Japanese Patent Laid-Open No. 5-30

  An air conditioner for a greenhouse for horticultural agriculture requires a large air flow to uniformly air-condition the room temperature in the house. However, in a general dehumidifying operation using a general-purpose packaged air conditioner, dehumidification is performed by reducing the air flow rate and lowering the evaporation temperature of the refrigerant in the evaporator of the refrigeration cycle. For this reason, since the amount of air blown during the dehumidifying operation is reduced, the room temperature in the house becomes uneven, and the room temperature in the house cannot be uniformly air-conditioned.

  An object of the present invention is to provide an air conditioner for a greenhouse for horticultural agriculture that can uniformly air-condition the room temperature in a house without reducing the amount of blown air during the dehumidifying operation.

  (1) In order to achieve the above object, the present invention provides an air conditioner for a greenhouse for horticultural agriculture having a refrigeration cycle comprising a compressor, a four-way valve, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger. In the above, the heat exchanger for reheating disposed on the downstream side of the air flow path of the indoor heat exchanger and the refrigerant flow path between the compressor and the four-way valve are branched and discharged from the compressor A part of the gas refrigerant is introduced into the reheat heat exchanger, and the liquid refrigerant liquefied by the reheat heat exchanger is joined to the refrigerant flow path between the expansion valve and the indoor heat exchanger. A reheat refrigerant circuit, a reheat expansion valve that is provided downstream of the reheat heat exchanger in the reheat refrigerant circuit and adjusts a refrigerant flow rate according to an opening thereof, and the reheat heat exchange A temperature sensor for detecting the air temperature, and a dehumidifier When performing, as the air temperature detected by the temperature sensor becomes a predetermined target value, and a control device for variably controlling the opening of the reheat expansion valve.

  (2) In the above (1), preferably, an on-off valve provided on the upstream side of the reheat heat exchanger in the reheat refrigerant circuit is provided, and the control device performs the cooling operation when performing the cooling operation. Control is performed to close the on-off valve and open the on-off valve when performing a dehumidifying operation.

  ADVANTAGE OF THE INVENTION According to this invention, the room temperature in a house can be air-conditioned uniformly, without reducing a ventilation volume in the case of a dehumidification operation.

It is the schematic showing the refrigerating cycle of the air conditioner for the greenhouses for gardening agriculture in one Embodiment of this invention. It is a block diagram showing the control apparatus of the air conditioner for the greenhouses for gardening agriculture in one Embodiment of this invention with a related apparatus.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

  The air conditioner for a greenhouse for horticultural agriculture according to this embodiment includes an outdoor unit 1, an indoor unit 2, and a control device (controller) 3. The outdoor unit 1 includes a compressor 4, a four-way valve 5, an outdoor heat exchanger 6, an outdoor blower 7, and an expansion valve (electronic expansion valve) 8. The indoor unit 2 includes an indoor heat exchanger 9 and an indoor fan 10. The compressor 4, the four-way valve 5, the outdoor heat exchanger 6, the expansion valve 8, and the indoor heat exchanger 9 are connected by a gas refrigerant pipe 11 and a liquid refrigerant pipe 12 as shown in the figure, so that a refrigeration cycle is achieved. Is configured.

  The outdoor unit 1 includes an on-off valve (solenoid valve) 13, and the indoor unit 2 includes a reheat heat exchanger 14 disposed on the downstream side of the air flow path of the indoor heat exchanger 9, and And a reheating expansion valve (electronic expansion valve) 15 for adjusting the refrigerant flow rate according to the opening degree. The on-off valve 13, the reheat heat exchanger 14, and the reheat expansion valve 15 are connected by a reheat gas refrigerant pipe 16 and a reheat liquid refrigerant pipe 17 as shown in the figure, so that the reheat refrigerant. The circuit is configured. More specifically, the reheat gas refrigerant pipe 16 is provided with an on-off valve 13, one end of which is branched and connected between the compressor 4 and the four-way valve 5, and the other end is a refrigerant of the reheat heat exchanger 14. Connected to the entrance. The reheating liquid refrigerant pipe 17 has a reheating expansion valve 15 interposed therein, one end connected to the refrigerant outlet of the reheating heat exchanger 14, and the other end connected to the expansion valve 8 and the indoor heat exchanger 9. Are joined together.

  The indoor unit 2 includes a temperature sensor 18 that is disposed on the downstream side of the ventilation path of the reheat heat exchanger 14 and detects the air temperature (that is, the temperature at which the air is blown into the house). The temperature sensor 18 outputs the detected air temperature to the control device 3.

  For example, an operating device (not shown) is connected to the control device 3 via a cable. By this operating device, switching of air-conditioning operation (specifically, cooling operation, dehumidifying operation, and heating operation) and a target of the room temperature in the house are performed. Values etc. are set and input. The air conditioning operation may be switched automatically according to a timer schedule that has been set and input. For example, when performing the dehumidifying operation, the control device 3 variably controls the opening degree of the reheating expansion valve 15 so that the air temperature detected by the temperature sensor 18 becomes a preset target value. It has become.

  Next, the operation of the air conditioner for a greenhouse for horticultural agriculture according to this embodiment will be described.

  When performing the cooling operation, the control device 3 sets the four-way valve 5 to the cooling / dehumidifying operation position (path indicated by a solid line in FIG. 1) and closes the on-off valve 13. Thereby, the high-temperature and high-pressure gas refrigerant discharged from the compressor 4 is supplied to the outdoor heat exchanger 6 via the four-way valve 5, cooled by the air blown from the outdoor blower 7, and condensed (liquefied). ) To become a liquid refrigerant. The liquid refrigerant is decompressed by the expansion valve 8 and then supplied to the indoor heat exchanger 9 and warmed by the air blown from the indoor blower 10 (in other words, the air is heated by the indoor heat exchanger 9). Cooled) and evaporated (vaporized) to become a low-temperature and low-pressure gas refrigerant. This gas refrigerant is returned to the compressor 4 via the four-way valve 5. And the air cooled with the indoor side heat exchanger 9 is supplied in a house through a duct (not shown), and the inside of a house is cooled.

  When performing the dehumidifying operation (so-called reheat dehumidifying operation), the control device 3 sets the four-way valve 5 to the cooling / dehumidifying operation position and opens the on-off valve 13. As a result, part of the high-temperature and high-pressure gas refrigerant discharged from the compressor 4 is supplied to the outdoor heat exchanger 6 and has the same flow as described above. On the other hand, the remainder of the high-temperature and high-pressure gas refrigerant discharged from the compressor 4 is supplied to the reheat heat exchanger 14 and is cooled by the air cooled by the indoor heat exchanger 9 (in other words, the air is regenerated). It is warmed by the heat exchanger 14 for heat) and condensed to become a liquid refrigerant. This liquid refrigerant is decompressed by the reheating expansion valve 15 and merges with the liquid refrigerant from the expansion valve 8. And the air cooled by the indoor side heat exchanger 9 and warmed by the reheat heat exchanger 14 is supplied into the house through the duct, and the inside of the house is dehumidified.

  Further, the control device 3 variably controls the opening degree of the reheating expansion valve 15 so that the air temperature detected by the temperature sensor 18, that is, the temperature at which the air is blown into the house becomes a preset target value. Thereby, the stability at room temperature in the house is enhanced.

  When performing the heating operation, the control device 3 sets the four-way valve 5 to the heating operation position (path indicated by the dotted line in FIG. 1), opens the on-off valve 13, and fully opens the reheating expansion valve 15. Accordingly, a part of the high-temperature and high-pressure gas refrigerant discharged from the compressor 4 is supplied to the indoor heat exchanger 9 via the four-way valve 5 and is cooled by the air blown from the indoor fan 10 ( In other words, the air is warmed by the indoor heat exchanger 9) and is condensed into a liquid refrigerant. This liquid refrigerant is decompressed by the expansion valve 8 and then supplied to the outdoor heat exchanger 6, warmed by the air blown from the outdoor blower 7, and evaporated to become a gas refrigerant. This gas refrigerant is returned to the compressor 4 via the four-way valve 5. On the other hand, the remainder of the high-temperature and high-pressure gas refrigerant discharged from the compressor 4 is supplied to the reheat heat exchanger 14 and cooled by the air from the indoor heat exchanger 9 (in other words, the air is used for reheating). It is warmed by the heat exchanger 14) and condenses into a liquid refrigerant. This liquid refrigerant is decompressed by the reheating expansion valve 15 and merges with the liquid refrigerant from the indoor heat exchanger 9. And the air heated by the indoor side heat exchanger 9 and the reheat heat exchanger 14 is supplied into the house through the duct, and the inside of the house is heated.

  As described above, since the so-called reheat dehumidifying operation is performed in the present embodiment, the room temperature in the house can be uniformly air-conditioned without reducing the amount of blown air during the dehumidifying operation. Further, since the reheat heat exchanger is used as a condenser during the heating operation, the heating capacity can be increased, and the heating load due to the combustion system equipment can be reduced.

DESCRIPTION OF SYMBOLS 3 Control apparatus 4 Compressor 5 Four-way valve 6 Outdoor heat exchanger 8 Expansion valve 9 Indoor heat exchanger 13 On-off valve 14 Heat exchanger for reheating 15 Expansion valve for reheating 18 Temperature sensor

Claims (2)

In an air conditioner for a horticultural agricultural greenhouse having a refrigeration cycle comprising a compressor, a four-way valve, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger,
A reheat heat exchanger disposed on the downstream side of the air flow path of the indoor heat exchanger;
A part of the gas refrigerant branched from the refrigerant flow path between the compressor and the four-way valve and discharged from the compressor is introduced into the reheat heat exchanger, and the reheat heat exchanger A reheat refrigerant circuit for joining the liquefied liquid refrigerant to a refrigerant flow path between the expansion valve and the indoor heat exchanger;
A reheating expansion valve that is provided on the downstream side of the reheating heat exchanger in the reheating refrigerant circuit and adjusts the refrigerant flow rate according to its opening;
A temperature sensor that is disposed on the downstream side of the air flow path of the heat exchanger for reheating and detects an air temperature;
And a control device that variably controls the opening degree of the reheating expansion valve so that the air temperature detected by the temperature sensor becomes a preset target value when performing the dehumidifying operation. Air conditioner for greenhouses for horticultural agriculture.   2. The air conditioner for a greenhouse for horticulture agriculture according to claim 1, further comprising an on-off valve provided on the upstream side of the reheat heat exchanger in the reheat refrigerant circuit, wherein the control device performs a cooling operation. An air conditioner for a greenhouse for horticultural agriculture, characterized in that the on-off valve is closed in the case, and the on-off valve is controlled to open when the dehumidifying operation is performed.

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