Study On Energy Saving Of Office Buildings With The Influence Of Daylighting

Comparing with lighting, daylighting can save energy and diminish the peak value ofbuilding energy consumption. Solar energy is exhaustless renewable energy, make use ofdaylighting can not only save illuminance energy consumption but also protect environment.Daylighting can make people in a good humor and improve work efficiency. Most domesticstudies on daylighting are only limited to qualitative analysis with the consideration of aestheticseffect, and no detailed and systematical quantitative study on daylight utilization with thecombination of daylighting and building energy consumption. Through a compendious sky model,numerical simulation is used to analyze the key factors affecting daylighting such aswindow-to-wall ratio (WWR), window styles, window orientation and shading device in thisthesis. And the influence of factors on daylighting distribution, lighting savings, cooling energyconsumption and heating energy consumption. Experimental model is made for practical testing tovalidate the result of simulation. More detailed information and conclusions about the thesis is asfollows.Describes the influence of shading devices on solar radiation heat gain ofwindows and analyzes the shading time and date of buildings. By choosing theshading time and date, calculates the right size of shading devices of differentorientation windows and gained the influence of shading devices on summer andwinter heat gain. The fitting shading time and date in Tianjin is: a room with a southaspect-shading in the whole day in the first ten days of August and sunning all the window at 12o'clock on Midwinter;a room with a east aspect-shading at 9 o'clock on Great Heat.A model of certain building is established calculation and analysis of the effect of WWR,shadings, window styles and window orientation on energy consumption of cooling and heating isconducted with the usage of TRNSYS software. The result is: westing windows have the greatestenergy consumption of cooling and northing windows have the least;northing windows have thegreatest energy consumption of heating and southing windows have the least. Energy consumptionsummation of southing windows is the least, northing windows is the greatest. Energyconsumption of north-south envelopment is littler than west-east envelopment. When WWRincreases, cooling energy consumption increases, heating energy consumption decreases and totalenergy consumption increases. With the decrease of shading factor and window's area, coolingenergy consumption decreases, heating energy consumption increases. If shading sizes aredesigned well, cooling energy decreases and heating energy consumption increases a little, totalenergy consumption decreases especially southing windows.Establishing a simple sky model that includes sun highness, building orientation and skycondition. According to solid angle projection law calculates the indoor illuminance cause bydaylight, analyses the influence of WWR, sill, windows styles and orientation, shading onilluminance distribution.The light saving is calculated in different daylight control style. Dimmer control style is moreefficient than off-on control style. Southing windows can save more energy than northingwindows. If WWR increases, the energy saving is enhances. The effect of shading on eastingwindows is more distinct than southing windows.The validation of the comparability of daylight distribution for building antetype and model ismade in the thesis. Due to the variable sky condition, daylighting factor is used for experimentalvalidation instead of illuminance. The error analysis of several testing methods used in theexperiment is conducted, followed by the experimental validation of the effect of WWR, skycondition, shading and transmittance on daylighting factor distribution. The results show that thesimulation data is credible.The energy consumption combination of daylighting, cooling and heating is calculated andanalyzed. The fitting WWR is attained in different windows style and orientation. Southingwindows: the feasible WWR of single-layer steel window (SS) is 20%, single-layer wood window(SW) is 25%, and double steel (DS) and wood window (DW) is about 40%. Easting windows:when WWR increases, energy consumption of SS and SW increases linearly. The feasible WWRof DS and DW is 25%. Northing windows: when WWR increases, energy consumption increaseslinearly. Instead that in dimmer control style, the fitting WWR of DS and DW is about 20%.Southing windows with shading: the windows with shading devices are more economical onenergy consumption than that without shadings. The feasible WWR of single-layer steel window(SS) is 25%, single-layer wood window (SW) is 30%, and double steel (DS) and wood window(DW) is about 45%. Easting windows with shading: the windows with shading devices are moreconsumptive on energy consumption than that without shadings. When WWR increases, energyconsumption of SS and SW increases linearly. The feasible WWR of DS is 20% and DW is 25%.