Xiaofei Zhen had completed his bachelor’s degree at the age of 23 years from Lanzhou university of technology. Now, he is working for his PhD. And he has published more than 2 papers in reputed journals. Besides, he is a member of the China Northwestern Collaborative Innovation Center of Low-carbon Urbanization Technologies.


The application of biogas production technology encounters great challenge in northwest of China. Low ambient temperature leads to low anaerobic fermentation temperature, low biogas production rate, unstability of biogas plant, and so on. Therefore, solar thermal energy was introduced to heat the biogas digester and two same thermostatic biogas digesters heated by solar water heater were developed and tested in winters of 2013 and 2014 in Gaolan County and Minqin County respectively. The thermostatic biogas digester was mainly comprised of 3 m3 fermentation tank, solar water heater with 30 pieces of 58×1800 evacuated glass tubes, and automatical temerature controller. The tests prove that it is a feasible way to thermostatic biogas production with the heating absorbed by evacuated glass tubes. The heat from solar water heater could easily guarantee the biogas digester works at 26 ℃ even when the ambient temperature is below -23.8℃. And 1.38m3 biogas is produced every day and the volume fraction of methane is usually over 54.7% with different fermentation raw material. Daily biogas production could meet the cooking energy demand for a family with 4-5 people. When the intensity of solar radiation is over 15.3MJ/m2, it is feasible for 1 m3 biogas digester to run steadily with 10 pieces of 58×1800 evacuated glass tubes, which means it is suitable for most Northwest regions of China. Besides, as a living fuel, biogas can save 730kg standard coal and 1095RMB per year for a family.