Greenhouse Heating Systems Theory And Designs

It is an urgently question that how to scientifically design a practical and economical heating system of greenhouse, which not only suiting crops growth but to utmost saving energy and protecting environment. And it is the main goal of this thesis. This article studied systematically design theory of the greenhouse heating system at first, and then illustrated some factors which affect the variety of temperature in greenhouse, Such as solar radiation, heating, heat exchange between buildings, heat exchange with soil and so on. Comprehensive and systematic analyses were done with greenhouse energy dissipation, the math models of heating load in greenhouse were given in the subtle way and estimating way. The principle was established with designing the capability of heating equipment according to the peak heating load in greenhouse and deciding fuel store by total heating load in a period of time. A program of greenhouse heating system were given.In this thesis, the characters and suitable object of heating by hot water, heating by hot wind, and heating the plant soil by heating wire were compared. About heating by hot water, the design method of the capability of the boiler, the lengths of the radiative pipeline, tubing method, flux of the hot water were presented in this thesis. About heating by hot wind, how to design the temperature of the wind, the blast quantity, and how to choice the air heater was approached. About heating way by heating wire, the account method of the capability of the equipment was introduced. At the same time, the design method of the hotbed and the laying of the heating wire were researched. For the purpose of decreasing the energy expense and solving the problem of air pollution and increasing economic efficiency and social efficiency of greenhouse management, to develop some new reasonable heating schemes based on energy-saving and environmental protection were regarded as the keystone in this work. An experiment was developed to investigate the temperature distribution in horizontal direction and vertical direction in a greenhouse which using a floor heating system. The result of the experiment showed that not only there was a better temperature distribution in the greenhouse but 35% of heat distributor investment, 27% of energy consumption were saved in this system. Solar energy conserved in soil is another new heating system in greenhouse. The energy-saving character of this system also was analyzed in this thesis. Heat pump, which is environmental protection heating equipment with high efficiency, was also analyzed. It has great application prospect in the areas of greenhouse heating. For soft energy-saving way: modern high-efficiency management technologies were analyzed.Expert system of designing greenhouse-heating system was developed primarily in the work to solve the complex design.