Study On Ventilation And Cooling Of Natural Cold Source In Qingdao Jiaozhou Bay Tunnel Substation

Due to the limited space in the tunnel substation,it is not enough to provide space for the ventilation scheme.Most tunnel substations use air-conditioning systems to maintain indoor temperature and humidity.With the improvement of China's tunnel construction technology and the enhancement of people's awareness of environmental protection,the development of natural energy as a cooling source for tunnel cooling systems in substations is of great significance for energy conservation and environmental protection.First,this paper introduces the research background and practical significance,summarizes the research status of ventilation and cooling in substation,and the natural cold source ventilation and cooling system.Then,according to the example of the Jiaozhou Bay Tunnel Project in Qingdao,a water leakage ventilation cooling scheme is proposed for its substation.Taking the Taixi three substation of the Jiaozhou Bay Tunnel in Qingdao as the research object,the numerical simulation of the three different air supply conditions is carried out.Based on the distribution of its temperature field,the energy efficiency and the indoor temperature distribution uniformity analysis,the requirements of substation temperature and humidity to meet when the air supply temperature of the ventilation and cooling system of leakage water is controlled at 30?.Then the study of the surface cooler in the ventilation and cooling system of leakage water is carried out,a method of analyzing the characteristics and performance of the surface cooler under non-standard operating conditions is presented,And the influence of different flow speed on the refrigerating capacity of the surface cooler is analyzed by this method.At the same time,the optimization design on the surface cooler was researched from the view of thermodynamics.It is concluded that the functional relation between the length of the base pipe length and the pipe diameter,When the maximum heat transfer amount is obtained.According to the above research,a fin type surface cooling device used in leakage water ventilation and cooling system is designed.At last,taking the ventilation and cooling system of leakage water of the Taixi three stations as an example,the technical,economic,environmental protection and other aspects of the system are analyzed.The results show that the operation cost of the ventilation and cooling system of leakage water is reduced by 67% which compared with the conventional air conditioning system,and the initial investment cost is reduced by 7%,and the operation process of the system does not cause any pollution and has certain environmental protection.