Usage strategy of phase change materials in plastic greenhouses, in hot summer and cold winter climate

Plastic greenhouses are basically used to create a warmed and protected growing area for plants. In the hot summer and cold winter climate, the consumption of the heating system for a greenhouse is the major operating cost. To reduce the production cost and limit the release of greenhouse gases, this investigation proposed the design of a latent heat storage system using phase change material for plastic greenhouses in this climate. Using a pilot in southern China, this study established a test bed of a greenhouse and developed a numerical model for designing the all-day use strategies in winter. The experimental data confirmed the feasibility of the strategy and validated the numerical model. Without using phase change material, the air temperature within the greenhouse could be as low as 3.7 degrees C; while the proposed strategy was able to maintain the indoor air temperature no less than 10 degrees C. The numerical model was further applied to design the all-day use strategies with different combinations of phase change material and insulation in a real greenhouse. The numerical simulations were able to help find the combination that satisfied the temperature requirement with the least investment. The payback time of the designed strategy was less than the lifespan.