Abstract:

【Objective】A photo-thermal resources based system for greenhouse climate zonation and energy consumption estimation was developed for dynamic climate zonation and identification of the distributions of photo-thermal resources and energy consumption for greenhouse crop production in China. 【Method】 First, 10 indices for greenhouse climate zonation were determined based on historical climate data set. Based on the values of the 10 indices, climate zonation was implemented by means of fuzzy C-Means (FCM) clustering method and a photo-thermal resources based system for dynamic climate zonation was developed. Secondly, a computer system was developed for climate zonation and energy consumption estimation for greenhouse crop production in China by integrating the photo-thermal resources based system for dynamic climate zonation with an energy balance based model for prediction greenhouse energy consumption. Thirdly, using 30 years (1971-2000) average daily weather data from 621 standard weather stations in China, a case study was conducted for greenhouse climate zonation and energy consumption estimation for a Venlo type greenhouse where infinite growth cucumber and tomato crops grow yearly around.【Result】The case study shows that China can be classified into 3 main regions (suitable, sub-suitable and unsuitable) and 9 sub-regions for greenhouse crop production. The suitable region is characterized with long period suitable for greenhouse crop production and low energy consumption for greenhouse heating. In this region, the major climate factor determining crop yield and profitability of greenhouse crop production is the total global ration during the period suitable for greenhouse crop production. The sub-suitable and unsuitable regions are characterized with long period and large energy consumption required for heating whereas low energy consumption for cooling in summer. In the later two regions, the major climate factor determining crop yield and profitability of greenhouse crop production is the accumulated negative temperature during the period for greenhouse heating. 【Conclusion】 The system developed in this study can be used not only for dynamic climate zonation and the identification of the distributions of photo-thermal resources for greenhouse crop production with historical climate data, but also for estimations of energy consumption for yearly around crop production in different types of greenhouse under different set-points for greenhouse temperature control. Therefore, the system has the potential to be used for assessing the risk for greenhouse investment and optimizing greenhouse structure and climate control from energy saving point of view.

Key words: greenhouse, energy consumption, system for climate zonation, photo-thermal resources