Energy-saving optimization of solar greenhouse walls in severe cold region

Abstract

ABSTRACT Energy consumption of solar greenhouse depends on the thermal insulation performance and thermal storage capacity of thermal storage wall. To find the best composition scheme for heat storage wall of greenhouse in severe cold region (1A: Hailar, 1B: Anda, 1C: Shenyang), the paper uses a typical Northeast Chinese solar greenhouse as an illustration and forms 14 schemes by setting expanded polystyrene (EPS) insulation boards and phase change materials (PCMs) at different positions of the thermal storage wall, of which PCM materials have six phase change temperatures. Energy consumption, wall heat storage performance, and room temperature of these schemes are analyzed by using EnergyPlus. Energy consumption, heat storage capacity, room temperature regulation, payback period, and carbon emissions were used to compare the heat storage wall schemes. The results show that Case Ⅵ (16°C) in Hailar is the optimal scheme, its energy consumption is 46,862.886 kWh, and the added value of the payback period is 1.87 years, the second is Case a and Case e (26°C) is the worst. Case VI (16°C) in Anda is the optimal scheme, its energy consumption is 65,599.749 kWh, and the added value of the payback period is 1.59 years, the second is Case a, and Case e (26°C) is the worst. Case Ⅶ (16°C) in Shenyang is the optimal scheme, its energy consumption is 26,109780kWh, and the added value of the payback period is 1.77 years, the second is Case a, and Case f (24°C) is the worst. The reason for the difference in optimal schemes is that the outdoor temperature of Hailar and Anda is low in winter, and PCM can hardly change phase in winter, but only plays the role of heat preservation. The temperature in Shenyang is relatively high in winter, and PCM is more likely to change phase, so the closer PCM is to the room, the lower the energy consumption of the greenhouse. The research results of this paper can provide a theoretical basis for the energy-saving design of solar greenhouse.