| With the growth of economic level of China,the total social demand for educational buildings and the quality of the internal light and heat environment have greatly increased.Relevant studies have shown that students have spent more than 80%of the time of studying in classrooms,and the light and heat comfort of the internal environment have a great impact on students’physical and mental health and learning efficiency.Affected by climatic conditions,air conditioners in educational buildings in Guangzhou are widely used,resulting in a surge in energy consumption.Energy saving has also become a factor that must be considered while improving building comfort.In this context,improving the indoor light-thermal comfort and reducing energy consumption of middle schools’classrooms have become urgent problems to be solved in the current educational building design.Therefore,this paper studies the optimized strategy of designing light-thermal comfort and of saving energy consumption on middle schools’classrooms in Guangzhou.Firstly,the Huangpu Experimental School of Guangdong Institute of Education was selected as a typical object.The light-thermal environment and energy consumption of middle schools’classrooms in Guangzhou were measured under the triple control,air conditioning and natural ventilation modes.The results showed that the non-uniform distribution of indoor thermal comfort was significantly affected by distribution of internal airflow velocity,incidence of direct solar radiation and thermal radiation emitted by glass.At the same time,the non-uniform distribution of indoor illuminance was influenced by windows,walls,corridors,etc.which was more significant in sunny days than cloudy days.Under the same weather condition,the indoor thermal environment of triple-controlled and air-conditioned classrooms,except for individual cases,was in a comfortable state.The indoor air velocity,temperature,relative humidity,and thermal comfort distribution of triple-controlled classrooms were more uniform than those of air-conditioned classrooms,and energy consumption of triple-controlled classrooms was less than that of air-conditioned classrooms.Secondly,the simulation and verification of the light-thermal environment and energy consumption of triple-controlled classrooms,air-conditioned classrooms,and natural ventilation classrooms were carried out based on the plug-ins of Ladybug and Honeybee embedded in the parametric platform of Rhino and Grasshopper.The simulation results were consistent with the measured ones,and the numerical differences were small.Therefore,it could be considered that the simulation methods and settings used in this paper were more accurate.Thirdly,considering that it will takes an amount of time to perform multi-objective optimization on all influencing factors at one time,this study decides to choose a step-by-step optimization method to preliminarily optimizes the sub-area lighting settings and triple control mode.By simulating a variety of sub-area dynamic lighting modes,it is found that with the number of sub-areas increases,the lighting power consumption shows a downward trend,with a maximum decrease of 48.41%.The horizontal 3-area lighting setting can better coordinate the building energy efficiency and setting.cost.By simulating and comparing various triple control modes,the 28°C triple control modes that the average wind speed is 0.4m/s is the preferred triple control mode,which the thermal comfort time ratio in the whole year,summer,spring and autumn can reach 96.25%,97.59%and 94.97%respectively,and the annual power consumption is only 42.31k Wh/m~2 on school days.Finally,on the basis of the optimal triple control mode,a multi-objective optimization based on genetic algorithm was carried out,which regarded the width,angle and distance from the window of the vertical shading member as variables and set the optimization of indoor light-thermal comfort and energy consumption as the goal.The set of Frontier solution demonstrated that the rate of energy-saving re-optimization rose up to 16.85%,and that of total energy-saving climbed up to 57.22%after re-optimizing the horizontal 3-zone lighting settings,which indicated that step-by-step optimization could not only improve the efficiency,but also guarantee the optimization results.Additionally,he recommended solutions were selected through comprehensive comparison after introducing the concept of non-uniform distribution of light-thermal environment into the evaluation criteria and further optimizing the above optimal solutions.In this paper,combining the triple control mode,sub-regional lighting settings and the evaluation standard of the non-uniform distribution of light-thermal environment,the conclusions could serve as the reference for the optimization method of light-thermal comfort and energy consumption in middle schools’classrooms in Guangzhou and other places. |
