Rooftop Greenhouse: (1) Design and Validation of a BES Model for a Plastic-Covered Greenhouse Considering the Tomato Crop Model and Natural Ventilation Characteristics

Abstract

Energy management of a building-integrated rooftop greenhouse (BiRTG) is considered one of the important factors. Accordingly, the interest in energy simulation models has increased. Energy load computed from the simulation model can be used for appropriate capacity calculation and optimal operation of the environmental control system. In particular, because the thermal environment of greenhouses is sensitive to the external weather environment, dynamic energy simulations, such as building energy simulation (BES), play an essential role in understanding the complex mechanisms of heat transfer in greenhouses. Depending on the type and crop density, there is a significant difference in the thermal energy loads of greenhouses. Furthermore, ventilation is also an important factor affecting the energy input of the greenhouse. Therefore, this study aimed to design and validate BES models considering the crop and ventilation characteristics of a naturally ventilated greenhouse before designing and evaluating a BES model for the BiRTG. First, the BES module for the greenhouse and crop models was designed using field-measured data, and the ventilation characteristics were analysed using computational fluid dynamics (CFD). The greenhouse BES model was designed and then validated by comparing air temperature (Ta) and relative humidity (RH) measured at the greenhouse with the BES-computed results of the greenhouse model. The results showed that the average absolute error of Ta was 1.57 °C and RH was 7.7%. The R2 of the designed BES model for Ta and RH were 0.96 and 0.89, respectively. These procedures and sub-modules developed were applied to the energy load calculation of BiRTG.