Solar energy powered greenhouse that provides cooling and freshwater to the plants. Parabolic trough collector provides energy to the organic Rankine cycle. Waste heat from the organic Rankine cycle operates the absorption cooling cycle. Greenhouse maintains optimum growing conditions and produces sufficient water. 1. Introduction
Increased proliferation of efficient solar greenhouses in China may contribute to solving worldwide problems such as the energy crisis and global climate change. This article summarizes the structure, function, application, and ecological benefits of energy-efficient, single-slope solar greenhouses in China, based on 20 years of systematic studies.
Single-slope, energy-efficient solar greenhouses in China use solar energy as the sole source of light and heat for winter crop production in the region between latitudes 32°N and 43°N. The use of solar greenhouses has greatly reduced energy demand and carbon dioxide (CO 2) emissions.
As the thermal energy increases, the temperature inside the greenhouse rises. Moreover, the rate of transpiration increases at higher levels of solar radiation, thus adding energy and water to the air flowing through the greenhouse.
The solar greenhouse is an important innovation in protected cultivation history, especially in this low carbon production era. It has many advantages in that they save energy, reduce pollution, and improve economic and social development. However, solar energy can be adversely affected by weather conditions.
The ecological benefits of solar greenhouse production in China are enormous. Because no heating is required in winter, the solar greenhouse saves an average of 750 Mg·ha −1 coal compared with the heated greenhouse. Currently, there are more than 0.74 million hectares of solar greenhouses in China ( Liu and Zou, 2007; Zhang, 2009 ).