A roof-mounted solar water heater
Photo credit: www.bcsea.org
China is by far the world’s largest producer and consumer of solar water heaters. A basic models of solar water heaters in China are very cheap, starting at around 1,500 yuan (US$190). By 2006, the cumulative installed area of water heating collectors in China hit 100 million square meters, and that is roughly 80 percent of the global solar thermal capacity installed worldwide. But this number corresponds only to 78 sqm of collector surface installed for every 1000 inhabitants, which implies a large margin of market potential. So, although China is the biggest solar thermal producer and market in the world, per capita installations of solar hot water systems are still quite low compared to countries like Israel, Greece, Cyprus, Germany and many others.
More than 30 million Chinese households now have one solar water heater installed, and the popularity is due to the efficient evacuated tubes which allow the heaters to function even under cloudy or smog-choked skies and at temperatures well below freezing. The evacuated tube technology was initially developed by Qing Hua University in Beijing in the early eighties, with pilot manufacturing in 1985.
A report from the China’s top planning authority predicted that by 2010, the coverage of solar water heating systems in operation in China will reach 150 million square meters. It is also estimated, that by utilizing solar energy, China can save more than 50 million tons of coal in 2010.