Study On The Influence Of Electrochromic Glass Window On Interior Environment And Control Strategy

In the building envelope,windows have an important impact on indoor heat gain,air conditioning energy consumption,and indoor occupant comfort compared to other building components.Therefore,seting appropriate shading devices for buildings is an effective method to reduce building energy consumption,improve indoor environments,and enhance occupant comfort.Electrochromic glass is a type of glass that can adjust the light transmittance by applying an external voltage.Compared to other shading devices such as exterior and interior shading,it has the advantages of being aesthetically pleasing,occupying less space,easy to adjust,easy to maintain,and low operating costs.This study investigated the impact of electrochromic glass windows on indoor environments and proposed control strategies,providing references for the practical application of electrochromic glass.The research team built three rooms with different shading devices(electrochromic glass windows,blinds,and ordinary glass windows)in Zhangjiakou City,Hebei Province,and equipped with air conditioning systems.Experimental and simulated comparative analyses were conducted to study the impact of electrochromic glass windows on indoor heat gain in summer,indoor heating supply in winter,indoor illuminance distribution,discomfort glare index,nighttime lighting transmittance,and human thermal comfort.A control strategy for electrochromic glass windows was developed,which can achieve the indoor comfort requirements by zoning control of electrochromic glass.The following conclusions were drawn in this paper:(1)In winter,the daily total heating supply of the electrochromic glass room was4.4% to 21.9% higher than that of the control room,while it was 12.2% to 32.7%lower than that of the blind room.In summer,through the heat transfer model of the room,it was calculated that the daily total heat gain of the electrochromic glass window room decreased by 19.1% to 41.8% compared to the control room.(2)In winter,the experimental results showed that the average indoor illuminance of the electrochromic glass room increased by 19.5% and decreased by87.2% compared to the blind room and the control room,respectively.The average indoor illuminance decreased by 25.2% when the electrochromic glass was in the colored state,and the indoor global illuminance distribution was more uniform when it was in the colored state.Through Ecotect simulation,it was found that the average indoor illuminance of the electrochromic glass decreased by 26.9% when it was in the colored state compared to the transparent state.In summer,the electrochromic glass in the colored state could also effectively reduce the average indoor illuminance and make the indoor global illuminance distribution more uniform.(3)During the day,the rooms with blinds and electrochromic glass had a better light environment,and most of the time met the discomfort glare index requirements.At night,the artificial illuminance at each position of the electrochromic glass room was higher than that of the control room,and the nighttime lighting transmittance provided by the electrochromic glass was 42% higher than that of ordinary glass.During the day,the rooms with blinds and electrochromic glass had a better light environment,and most of the time met the discomfort glare index requirements.At night,the illuminance at each position of the electrochromic glass window was higher than that of the control room,and the nighttime lighting transmittance provided by the electrochromic glass was 42% higher than that of ordinary glass.(4)In winter on sunny days,the PMV value of the electrochromic glass room changed more steadily than that of the control room,but the PPD and SET* values of the electrochromic glass room were not as good as those of the control room.In summer,the electrochromic glass room had a better thermal comfort performance than the other two rooms,with lower PMV,PPD,and SET* values.(5)Based on the feature that electrically switchable glass windows can be controlled separately by zone,a control strategy for electrically switchable glass windows based on reinforcement learning algorithm has been developed.This strategy effectively solves the effect of excessive daylighting affecting indoor comfort.Moreover,this control strategy can improve both the illumination comfort and temperature comfort of the indoor environment.Research shows that,in terms of reducing summer cooling load,the control effect of electrically switchable glass windows based on light sensing control is superior to that based on temperature sensing control.