Study On The Wall Hung Solar Assisted Heating System Of Ecological Greenhouse

Greenhouse plays a very important role in ensuring the normal growth of vegetable crops in the northern winter of China. But in the northern winter extreme climate and even cloudy and other adverse conditions, the greenhouse with no assisted equipment can not meet the plant’s normal growth conditions. In order to solve this problem, assisted heating system heating equipment of the traditional greenhouse is mainly a coal fired boiler, oil fired boiler, fuel fan, heating wire, while the heating method has high operation cost, consuming energy, environmental pollution and other shortcomings. In view of the above questions, this paper proposes a new type of greenhouse assisted heating method. Compared with the traditional auxiliary heating way-the characteristics of new type of greenhouse assisted heating method is pollution-free, pollution-free, easy access, inexhaustible and so on, which provides a new way for the greenhouse warming in winter. This paper mainly includes the following contents:1.Proposed a new greenhouse assisted heating system-the wall hung solar heating assisted system, the system consist of collector system, tank, Storage and control system, cooling system. The solar collector solar radiation energy into heat insulation and stored in water in the tank, a circulating pump and a control system for opening night, the daytime heating water circulating in the cooling system in order to improve the temperature in greenhouse at night.2.In order to improve the radiating efficiency of the cooling system, analysis heat transfer mechanism of the wall hung solar assisted heating system of the ecological greenhouse. Establish greenhouse temperature field of two-dimensional model, and select factors and levels influenced the cooling system. Determined by simulation test scheme of orthogonal experiment table, the primary and secondary factors that affect the heat dissipation system are as follows:fluid temperature, pipe spacing and pipe diameter. At the same time according to the actual situation of the test site, to determine the optimum parameters for the tube diameter 25mm, distance 200mm.3.Continuous warming experiment is carried out on the wall hung solar assisted heating system of the ecological greenhouse, and the temperature distribution of the horizontal direction and the environmental factors are tested in the greenhouse. The experimental results show that:ecological greenhouse with the wall hung solar assisted heating system, sunny day air temperature increase 2.1～4.5℃, the soil temperature increase 1.0～1.4℃, cloudy day air temperature increase 0.9～1.8℃, the soil temperature increase 0.5～0.8℃. The temperature difference is small in the whole greenhouse on cloudy day. Sunny day the temperature difference is large because the collector system collects more solar energy due to strong solar radiation and the opening night of heating system. Sunny day due to temperature difference, strong solar radiation, due to the opening night of heating system, leading to that the closer to the back wall, the higher the temperature, the better the heating effect. At the same time, compare and analysis the test values and the simulated values, the results show that, the numerical value of the model is in good agreement with the measured values of the heating test in the numerical and variation trends, which verifies the accuracy of the model.This paper studies the wall hung solar assisted heating system of the ecological greenhouse of the utility has been verified, to achieve the requirements of energy-saving and environmental protection, so as to ensure the growth of crops in greenhouse.