JPH022211Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a temperature control device for a greenhouse suitable for cultivating and growing various plants.

[Conventional technology]

In order to maintain the greenhouse at an appropriate temperature for cultivating and growing various plants, the heat pump absorbs the excess heat during the daytime when the temperature in the greenhouse rises above the above-mentioned holding temperature due to surplus heat. Heating a suitable fluid with the heat of condensation, guiding the fluid to an underground pipe and accumulating the condensation heat in underground soil (including gravel, sand, pebbles, water, etc.), etc. The heat pump device is stopped at night, and when the temperature inside the greenhouse falls below a temperature suitable for maintaining the growth, the accumulated heat is guided to an appropriate heat exchanger in the greenhouse by the fluid and released. It has been known in the past to heat the inside of a greenhouse by If there is a large temperature difference between the greenhouse and the high-temperature greenhouse, there is a disadvantage that dew is likely to occur inside the greenhouse. Another disadvantage is that the heat inside the greenhouse is wastefully dissipated into the outside air. The present invention aims to eliminate such drawbacks.

[Means to resolve the problem]

During the day, the heat pump device absorbs the excess heat that raises the inside of the greenhouse above the temperature at which the plants are grown, heats the fluid with the condensation heat of the heat pump device, and guides the fluid to underground pipes to transfer the condensed heat to the ground. At night, the heat pump device is stopped and the fluid is circulated between underground pipes and a heat exchanger in the greenhouse to release the accumulated heat and heat the greenhouse. In this temperature control system, the evaporator of the heat pump is connected to an inlet duct that brings hot and humid air into the greenhouse, an outflow duct that lets cooled air flow out toward the ceiling of the greenhouse, and a An air passage is provided in the greenhouse to allow the cooled air to flow down along the inner surface of the ceiling.

In the present invention, a greenhouse refers to a room that is constructed of a transparent material such as vinyl or glass so that sunlight can easily pass through, and that can be maintained at a temperature suitable for cultivating and growing plants.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings. 1
is a greenhouse for cultivation, and the heat pump device consists of a heat pump unit 2 housing a compressor and a condenser, expansion valves 3, 4, evaporators 5, 6, and shutoff valves 7, 8. The evaporator 6 uses groundwater as a heat source. 9 is a pump that circulates a fluid for heat transport; 10 is a heat exchanger for heating the greenhouse;
Reference numeral 11 indicates an underground pipe for storing condensed heat in underground soil, reference numerals 12 and 13 indicate shutoff valves, and reference numeral 14 indicates a plant being grown.

When operating a heat pump device during the day,
The liquefied refrigerant that has exited the condenser of the heat pump unit 2 flows through the expansion valve 3 or 4 into the evaporator 5 in the greenhouse 1 for cultivation or the evaporator 6 for underground water, where it evaporates and absorbs heat. 8, it returns to the compressor in the heat pump unit 2, and after being compressed, it enters the condenser again and releases the heat of condensation.

The system for introducing the condensed heat into the cultivation greenhouse 1 is constructed as follows. The fluid that has absorbed the condensation heat in the heat pump unit 2 is introduced into the underground pipe 11 by the pump 9, where it radiates heat into the ground and is stored in the soil, and then returns to the heat pump unit 2 via the shutoff valve 12 to form a circulation path. . Shutoff valve 1
2 and opening the shutoff valve 13, the heating heat exchanger 10 installed near the ground surface in the greenhouse communicates with the underground pipe 11, and the fluid is introduced into the heating heat exchanger 10 and accumulated in the soil. The heat is released to a location high above the ground within the greenhouse 1 for cultivation.

Excess heat in the greenhouse during the daytime is absorbed by the evaporator 5, but if even this amount of heat is insufficient for the amount of heat stored underground, the evaporator 6 is also used.

An inflow duct 15 is connected to the evaporator 5 in the greenhouse 1 for inflowing hot and humid air present above the plants in the greenhouse, and an outflow duct 16 is connected to the air outflow side of the evaporator 5 with its outlet facing upward. The air cooled by the evaporator 5 is discharged toward the ceiling of the greenhouse 1. The air is caused to flow down along the inner surface of the ceiling 17, which is the roof, and then along the inner surfaces of the side walls 18. By circulating the air in the greenhouse in this way, a layer of air is formed between the low-temperature outside air and the high-temperature inside of the greenhouse 1 through the air passage 20, which has an intermediate temperature between the two, so the temperature difference becomes small, and the greenhouse It is possible to reduce the rate at which the heat inside the greenhouse 1 is wastefully dissipated into the outside air, thereby making effective use of the heat, and at the same time, it is possible to reduce the occurrence of dew inside the greenhouse 1. Note that 19 is a vinyl sheet, which is drawn as a curtain to prevent the heat inside the greenhouse 1 from dissipating to the outside at night, and is used as a heat-insulating film.

Note that when the amount of heat stored underground becomes sufficient, the operation of the heat pump device may be stopped or the ventilation windows of the greenhouse may be opened.

[Effect of idea]

In this type of greenhouse, as the cultivated plants grow, more water is released from the plants, and the amount of heat accumulated on the plants in the greenhouse gradually increases, so the air containing a large amount of this heat is evaporated. The air that has been cooled as a result of heat absorption rises toward the ceiling of the greenhouse, and then flows down along the inner surface of the roof of the ceiling and, if necessary, the inner surface of the side walls, thereby reducing the high temperature inside the greenhouse and the low temperature outside. A circulating layer of air at an intermediate temperature is formed in between. This reduces the temperature gradient compared to when the high temperature inside the greenhouse and the low temperature outside air come into direct contact through vinyl or glass, reducing heat loss dissipated from inside the greenhouse to the outside air and reducing dew. The occurrence can also be reduced.

[Brief explanation of the drawing]

The figure is a flow sheet diagram of an embodiment of the present invention. 1... Greenhouse, 2... Heat pump unit of heat pump device, 5... Evaporator of heat pump device, 10... Heat exchanger for heating, 11... Underground pipe, 15... Inflow duct, 16... Outflow duct ,
20...Air passage.

Claims (1)

[Scope of utility model registration request] During the day, the heat pump device absorbs the excess heat that raises the inside of the greenhouse above the temperature at which the plants are grown, heats the fluid with the condensation heat of the heat pump device, and guides the fluid to underground pipes to transfer the condensed heat to the ground. At night, the heat pump device is stopped and the fluid is circulated between underground pipes and a heat exchanger in the greenhouse to release the accumulated heat and heat the greenhouse. In this temperature control device, an inflow duct that allows hot and humid air in the greenhouse to flow in and an outflow duct that flows out cooled air toward the ceiling of the greenhouse are connected to the evaporator of the heat pump device, and the outflow duct is connected to the evaporator of the heat pump device. A temperature control device for a greenhouse, characterized in that an air passage is provided in the greenhouse for causing the cooled air to flow down along the inner surface of the ceiling.