CHINA’S SOLAR GREENHOUSES

Solar greenhouses: China's winning solution to global energy crisis; 20 years of research produces definitive study on benefits of Chinese single-slope greenhouses
17 March 2011 (EurekAlert)

"Solar greenhouses have played a vital role in China's agricultural scene for years. New innovations in greenhouse design are allowing growers to produce more varieties of vegetables, even during long winter months…[In Structure, Function, Application, and Ecological Benefit of a Single-slope, Energy-efficient Solar Greenhouse in China] researchers from the College of Agronomy and Biotechnology at China Agricultural University presented an extensive report on single-slope solar greenhouses in a recent issue of HortTechnology. Based on 20 years of systematic studies, the report noted…efficient solar greenhouses in China…[could help solve] problems such as the energy crisis and global climate change…

"Single-slope solar greenhouses are built facing south using support and insulation walls on the north, east, and west sides. A short roof is installed on top of the north wall. The south side is supported by metal or bamboo frames (or a mixture of both materials), and is covered with plastic film and an insulating blanket. These energy-efficient greenhouses use solar energy as the only source of light and heat for winter crop production in the region between latitudes 32°N and 43°N for production of warm season crops such as tomato and cucumber."

Chinese solar greenhouses at work (click to enlarge)

"As in other parts of the world, the feasibility of using solar greenhouses in China largely depends on the relative duration of sunshine in the winter and temperatures at the greenhouse site. Solar greenhouses are widely used in the regions north of Huai River and the Beijing area…[U]sage has greatly reduced energy demand and carbon dioxide emissions…[leading to] adoption by countries such as Japan, Korea, and Russia."

One of the study authors in a soalr greenhouse (click to enlarge)

"The researchers noted that while solar greenhouses have many advantages—energy savings, reduced pollution, and improved economic development—the structures also have distinct disadvantages due to their heavy reliance on the sun and weather conditions…[compromised] solar radiation and low temperatures can have a significant negative impact on warm-season vegetable productivity…

"…[The study recommended more innovation and optimization] of the…gutter-connected, double-arched, and semi-underground greenhouses…[new, thinner] wall insulation materials…[and] breeding new varieties of horticultural crops that can adapt to low light and winter temperatures in solar greenhouses…"