1. BP statistical review of world energy; 2013. bp.com/statisticalreview.
2. Yearbook of energy statistics of China;Department of Energy Statistics of National Statistics Bureau of China,2011
3. Division of Chinese Academy of Science, Study on the current state of industrial energy-saving and the measurements. Academicians and Department. vol. 25; 2010. p. 307–9 [in Chinese].
4. The handbook of heat pump technology;Chen,2012
5. Study on the performance of a solar assisted air source heat pump system for building heating;Liang;Energy Build,2011