In Korea, 77.6% of horticultural greenhouses use hot air heating systems, and the use of air circulation fans are increasing every year, to manage the inside environmental conditions of the greenhouses. As for the air circulation fans, they are generally installed in the horizontal direction, which leads to a lack of air circulation for the crops in the lower levels.
Even when the hot air heater is operating, the warm air would accumulate in the upper levels of the greenhouse, leading to uneven internal temperature and humidity, causing the disease and increasing the energy consumption. In addition, the greenhouses that were built in recent years have high sidewalls that are above six meters, so it’s been challenging for farmers to manage the temperature differences by using only the horizontal air circulation fans.
In order to overcome such shortcomings, Sysco Co., Ltd. developed an angle changeable fan that detects the temperature inside the greenhouse and automatically changes the direction of the wind with its air circulating fan, direction-change motor, angle control device and smart controller.
When the product was experimented in greenhouses that grow tomatoes, paprika and lilies, as the result, the heat was quickly released during the summer by 6.4 ℃ (44 ℃ → 37.6 ℃) compared to existing heating management system. In the winter, the greenhouses equipped with horizontal circulation fans showed 1.3 ℃ and 8.4% differences in temperature and humidity. However, after installing the angle changeable fans, it showed only 0.6 ℃ and 2.7% differences in temperature and humidity.
When the warm airs at the top of the greenhouse were sent to the bottom where the crops were placed, it resulted in the reduction of heating energy, from 5.0% to 8.8%, compared to when using the existing heating systems. In the case of cherry tomatoes, the initial yield increased by 8.5%, and the pests decreased significantly.
When the temperature differences are moderate, the system automatically operates the angle changeable fan in the horizontal direction as per usual. The optimal growth environment can be achieved through the circulation management of air inside the greenhouse, which has already been proved for its effectiveness and installed in numerous farms in Korea.