Applied Research On Optimization Method Of District Heating Source Schemes In Lhasa

Lhasa is located at the Lhasa river valley sides, and located in the cold area. It has the characteristics of abundant solar energy resources, big temperature difference between day and night, small air relative humidity, and the lack of fossil energy, fragile ecological environment, etc. Presently, building heating facilities are under construction for perfecting the urban functions, since there is only one batch of heating pilot project in Lhasa. How to determine the scientific and reasonable scheme of heating source, maintain the ecological environment, and reduce the energy consumption in Lhasa area is a looming problem.In this paper, first of all, the energy resources of the heating source in the Lhasa area was introduced, and the feasibility of energy resources utilization was assessed. The richness degree and stability of solar energy resources, and the suitability of Ground Source Heat Pump system, the feasibility of air energy resources utilization, gas supply and demand balance relations as well as the supply of electric energy were analyzed in detail.Secondly, according to the principle of the construction of evaluation index system and the influencing factors of the scheme optimization of heating source in Lhasa, the hierarchy structure of heating source scheme evaluation index system was established for the sustainable development of the Lhasa area, which consists of a total of eight indicators from three views of economy, technology, energy conservation and environmental protection, and various indicators were interpreted. Comprehensive empowerment method was put forward with the combination of subjective and objective weight methods on the basis of the analysis of the advantages and disadvantages of subjective and objective weight methods. The comprehensive evaluation optimization model of heating source scheme was established based on comprehensive empowerment method.Then, the use state of typical construction of certain university in Lhasa was investigated and analyzed. Based on the survey data, the heating load of the teaching buildings and student dormitories was calculated by the DeST simulation software, and the heating load characteristic was analyzed.Finally, according to the function characteristics of typical construction of certain university in Lhasa and the analysis of energy structure, three alternative heating source schemes were put forward. At the same time, the theoretical calculation model of the solar radiation on inclined surfaces has been established, the intensity of direct solar radiation and diffuse solar radiation, the intensity of ground reflection and total radiation have been obtained. Then, district heating source schemes of certain university in Lhasa were evaluated comprehensively by optimization mathematical model based on comprehensive empowerment method. The evaluation results were given under two situations by the difference of ranking of Level one index. The results show that the second scheme is optimal in both situations. In other words, that energy station one adopts solar energy heat pump system and energy station two adopts gas boiler heat source system is optimal.