A Review on Energy-Sustainable Design and Operation of Greenhouses for Plant/Crop Production in Cold Regions

The energy consumption of greenhouses in cold regions, especially for space heating, is immense and therefore economically unbearable. The main objective of this article is to provide a comprehensive review of state-of-the-art energy-saving strategies for the design and operation of greenhouses in cold regions. The review covers conventional functions (lighting, air quality and temperature control, and irrigation), nonconventional functions (thermal insulation, thermal energy storage, and utilization of ground-source and renewable energy), and numerical modelling of the energy-performance of greenhouses. For each of these topics, pertinent plant science is provided and performance assessments are presented. The findings from this review conclude that hybrid lighting (LED with high-pressure sodium lamps) and proper scheduling result in the best combination of energy efficiency and plant yield. However, further studies are still required in this field.