Study On Energy Efficient Design Of Substation Buildings In The Hot-humid Area Of China

With the acceleration of urbanization process and the improvement of residents’living standards,the power loads of cities have increased rapidly,and the large-scale construction of substations is imminent.The building energy consumptions stay in a high level for the typical indoor substations in the hot and humid area due to the lacking of guidance by specific energy efficient design standards on substation buildings.Taking 220k V indoor substations in Guangzhou as the research object,with the goal of reducing building energy consumption,this study determined the influencing factors of substation energy consumption,established typical substation building models,investigated the impact of various factors on building energy consumption,and finally put forward a building energy efficient design strategy suitable for substations in the hot and humid areas by using methods of literature survey,on-site measurement,numerical simulation and parameterized optimization.The main work and conclusions are as follows:(1)The thermal characteristics of typical substation buildings was obtained through literature survey and on-site measurement:the energy consumption of substation buildings is mainly on air conditioning(AC);the structure of envelope is similar to that of public buildings,and the energy efficient design of envelope is mainly on heat insulation and less on heat dissipation;the equipment room with large internal heat disturbance use split-type air conditioner for cooling,with the set temperature of 26°C,and operational time of 24 hours and365 days.(2)The impact of single factor on AC energy consumption of substation building was analyzed through simulation,together with the sensitivity analysis of simulation results.The results show that the order of influence degree for various factors is as follows:external wall heat transfer coefficient>roof heat transfer coefficient>AC set temperature>external window shading coefficient>external window heat transfer coefficient>building orientation.The heat transfer performances of the external wall and roof are the focus of the energy efficient design of substation building envelope.Energy saving can be achieved by increasing the heat transfer coefficient of the external wall and roof,i.e.,by increasing the heat dissipation of envelope.(3)The impact of multiple factors on AC energy consumption of substation buildings was analyzed through simulation.Taking the minimum annual AC cooling load of as the optimization goal,the multi-variable optimization was carried out for the key influencing factors of energy consumption.The recommended factor values for energy saving of substations in the hot and humidity area were obtained as follows:external wall heat transfer coefficient of3 W/(m~2·K),roof heat transfer coefficient of 2 W/(m~2·K),external window solar shading coefficient of 0.23,external window heat transfer coefficient of 6 W/(m~2·K),AC set temperature of 30℃,and building orientation of 15°south-east.(4)Combining the simulation results of the single and multiple factors studies,the integrated energy efficient design strategy was provided for the substations in the hot and humid area as follows:moderately increase the AC set temperature under the premise of ensuring the safe operation of electrical equipment,focus the energy efficient envelope design on improving heat dissipation performance,thermal design follows with the recommended values or ranges:external wall heat transfer coefficient of 3-6 W/(m~2·K),roof heat transfer coefficient of 2-3W/(m~2·K),higher external window heat transfer coefficient and lower external window solar shading coefficient.