Design of a Geothermal Greenhouse Microclimate Model and Computer Simulation

Abstract

In China, the living standards of the people are rising quite rapidly. It's getting more imperative to research and develop modern food production systems. China is rich in moderate- and low-temperature geothermal resources and, this will play a very important role in the dynamics of large-scale greenhouse development. Both in fundamental theories and construction technology of greenhouses, China is, however, relatively underdeveloped. To counter this situation, a greenhouse microclimate model is developed through an extensive review of existing literature. This model may simulate the transient processes in geothermally heated greenhouses with subsurface soil warming systems and, predict the time-dependent parameters that are of significance in greenhouse design. Like previous models, this model also consists of: a soil layer, a vegetation layer, an air layer and a cover layer. While the microclimate was thoroughly investigated, the utilization of geothermal energy shares particular interest. In order to validate the model, numerical experiments were conducted. Comparison showed that the results of the simulation had been in good agreement with that both from practical measurements and from existing literature. These numerical experiments also demonstrated, to some extent, the sensitivity of the model to some parameters. We hope that this model can contribute methodologically to the research and development of greenhouses in China.