SHALLOW GEOTHERMAL RESOURCES AND GHP UTILIZATION IN BEIJING

摘要

There is a great deal of low temperature resources at shallow depth under Beijing. Because the temperature at shallow depth is generally too low, it can not be used directly for heating. But, with the development of heat pump techniques, this energy can not only be used for space heating, but also for cooling. Shallow geothermal is an example of green and renewable energy. Geothermal heat pump (GHP) systems are used widely in the world. Beijing is a city with a population of 17 million. The needs for space heating and cooling are ever increasing, with the fast expansion of construction and improvement of living conditions. The energy consumption of Beijing has been in the second place in China, and the government is paying great attention to adjusting the energy structure, promoting the use of renewable energy and energy saving. In addition, the air pollution in Beijing has become very serious. Air pollution control is also a most important task in Beijing, and this is amplified with the 29th Olympic Games being held in Beijing in 2008. In the area of Beijing, there are very good conditions for the utilization of shallow geothermal resources. Firstly, it is hot in the summer and cold in the winter in Beijing, and the heating and cooling needs are equally great. Secondly, the sediment of the Quaternary System in the Beijing plain is suitable for installation of GHP systems, either open loop systems or closed loop systems. The first two GHP systems were put into operation in the summer of 2000. After that, the GHP utilization developed rapidly. There have been 479 such systems and the service area has been over 10 million m2 till September 2007. At the beginning, most of the underground heat exchangers were open loop, that is with a group of pumping and reinjection wells. After 2005, more closed loop systems were installed, i.e. down-hole heat exchangers. GHP systems are economically viable. In addition, the environmental effects of GHP system are also remarkable. From 2000 to 2007, the total amount of energy savings through the use of GHP systems in Beijing is estimated as 2.37><1013 kJ, accounting for the heat of 1.35><106 tons of coal and 3.21 xlO6 tons of CO2 emission reduction.