Greenhouse Heating Solution

Plant physiological responses are complex physicochemical reactions and are most affected by temperature. The temperature within the range where crops can grow is called the effective temperature, and the lowest temperature at which the crop can grow is called the minimum temperature. The highest temperature at which crops can grow is called the highest temperature, and the temperature at which growth is most vigorous is called the optimum temperature. This is not only different depending on the growth stage of the crop and the type of crop, but also the optimum temperature for growth during the day and night. The viable temperature for each crop can be divided into the lowest temperature limit, the optimum temperature for growth, and the highest temperature limit. Plants grow best at the right temperature. Growth is possible up to the limit temperature, but the further away from the appropriate temperature, the slower the growth. And when it exceeds the limit temperature, various types of low-temperature or high-temperature disturbances are indicated. It is important to manage the temperature environment of facility horticulture to keep the temperature within the limit in the temperature management of the facility.

Heat loss in the greenhouse consists of three types of conduction radiation leakage. Of these, 80% of the heating load is caused by conduction, which is a phenomenon that flows from a high temperature to a low temperature by heat transfer through the ground of the greenhouse covered structure. It can be regarded as the same principle as the flow from high to low. Here, the greater the temperature difference between the inside and outside of the greenhouse, the greater the amount of heat loss. The higher the indoor temperature and the lower the outdoor temperature, the more heat is lost to the outside in proportion. For this reason, in order to reduce the heating load, it is necessary to lower the temperature difference between indoor and outdoor. Here, the outdoor temperature is an area that cannot be controlled, so the indoor temperature should be lowered. During the daytime, when carbon assimilation is active, the temperature is raised, and at night, the plant is sleeping because there is no sunlight. block Next, as a factor influencing the conduction load, as the heat transfer coefficient of the ground of the insulation structure increases, the amount of heat loss also increases in proportion, and the main part is the heat loss through the insulation material.

The more vinyl layers there are, the greater the warming effect. That is, the air layer between vinyl and vinyl also has a significant thermal insulation effect, so the thermal insulation effect of the triple greenhouse is better than that of the double greenhouse. This is better than the insulation of the air layer and the insulation of the insulation cover is superior to that of vinyl. The insulation cover is also better than the one-ply thick insulation cover, because the double insulation cover has an air layer in the middle, so it has good thermal insulation properties. Since it acts as a facility overload such as switchgear and tugboat, safety and economics should be considered when designing this part.

Next, the most occupied part is the interpolar wind through the gap of the greenhouse heat insulating layer structure. Since the amount of direct heat loss caused by outside air that occurs when coming and going to and from a gap like this is 15% of the total heat loss, it is an amount that cannot be ignored. A design that minimizes In addition, as the difference between indoor and outdoor air pressures increases, the amount of leakage increases. Therefore, proper indoor temperature, that is, heating management is important. Like heat loss due to conduction, heat loss due to leakage is also important to keep the temperature difference between indoor and outdoor pressures low. It is advantageous to design a lot of used air layers. However, this is an area that cannot be designed blindly. Design review by an experienced expert who can closely examine economic feasibility such as heating cost and construction cost in greenhouse design based on the optimal design temperature according to the location of each region, the type of cultivated crop, the cultivation method, etc. is needed

There are many parts that are difficult to seal in the structure of the entrance door of the greenhouse. For the convenience of material transport in Yeondong House, there are many cases of installing doors and overlooking the heat loss caused by interpole winds. Measures must be taken to arrange the design of the movement, such as movement, so that the inside of the greenhouse can be used, and to block the interpole air volume through the ventilation hole. Other than that, the amount of heat loss through radiation is negligible.