Comparison of energy consumption: greenhouses and plant factories

Annual energy consumption and carbon footprints are compared in simulation for two controlled environments: plant factory and traditional greenhouse. Energy consumed for heating, ventilating, and air conditioning (HVAC) as well as supplemental lighting are included in the models. In the greenhouse case, supplemental lighting is controlled to a consistent daily light integral (DLI) of Photosynthetically Active Radiation (PAR) using Light and Shade System Implementation (LASSI). In the plant factory model, lighting power is sized according to photoperiod and DLI requirements. Building HVAC loads and system responses are computed using the ASHRAE heat balance method with a one hour time-step. Both environments are simulated in four different climates using Typical Meteorological Year (TMY) data sets. In each simulation, energy consumption and carbon footprints are shown to be significantly higher in the plant factory environment compared to the greenhouse.