ارزيابي چگونگي تاثيرگذاري بام سبز در كاهش دماي محيط

The Effect of Green Roof on Reducing Environment Temperature

بام سبز بامي است كه با محيط كشت روينده پوشانده ميشود. ايجاد سبزينگي در فضاي پشت بام بر آب و هواي شهر و منطقه و هواي داخل ساختمان تاثير مثبت داشته و با ممانعت از تابش اشعه هاي خورشيدي در خنكسازي فضا نقش دارد. اين خنكسازي با كاهش نوسانات گرمايي بر روي سطح خارجي بام و از طريق افزايش ظرفيت گرمايي بام صورت ميگيرد كه فضاي زير بام را در تابستان خنك نگه داشته و ميزان گرمايش را در طي زمستان افزايش ميدهد. يكي از راهكارهايي كه براي كاهش مصرف انرژي در شهرهاي كلان پيشنهاد ميشود، احداث باغ بام است. باغ بام يا بام سبز چنانچه صحيح طراحي و اجرا و در آن ملاحظات اقليمي در نظر گرفته شود علاوه بر مزاياي مختلف ميتواند تا حد زيادي به كاهش مصرف انرژي كمك كند. در اين تحقيق مزاياي بام سبز مورد ارزيابي قرار گرفته و براي اثبات اين فرضيه كه "بام سبز و چگونگي طراحي آن نقش موثري در كاهش انتقال حرارت دارد" از نرمافزاري تحليلي به نام انسيس استفاده شده است. سه نمونه بام معمولي، بام سبز معمولي، بام سبز با جزييات اجرايي خاص (لايه فايبرگلاس) آناليز شده و انتقال حرارت آنها مورد مقايسه تطبيقي قرار گرفت و معلوم شد كه بام سبز نسبت به بام معمولي 50 درصد انتقال حرارت كمتري دارد و بام سبز با لايه فايبرگلاس نسبت به بام سبز اجرايي 40 درصد بهينهسازي شده است. سايه اندازي و خنكسازي تبخيري گياهان و همچنين لايه هاي سقف به عنوان عايق تاثير موثري در كاهش انتقال حرارت دارند. رويكرد اين پژوهش علمي- كاربردي بوده است. روش تحقيق در بخشهاي مربوط به مزاياي بام سبز، توصيفي و نوع تحقيق، كيفي و در بخشهاي مربوط به تحليل نرمافزاري نوع تحقيق كمي و روش، تحليلي بوده است.

Green roof is a roof which is mostly covered with vegetation and soil or is covered with vegetative medium. Chlorophyll creation has a positive impact on the climate of the city and can also contribute positively to providing cool air inside the buildings. This cooling of air occurs through reducing the penetration of heat through the roof and providing a stronger insulation to prevent indoor air to become warm. As a result, the indoors temperature can be easily decreased during summer and increased during winter. Reducing energy consumption is one of the major concerns for sustainability in cities. Creating roof garden is suggested as one of the ways to reduce energy consumption in major cities. Roof garden or green roof - if properly designed and implemented by considering climate issues - can greatly help to reduce energy consumption. Changing buildings roofs to green roofs could improve the exchange of air between areas of high building density and open spaces between them and accordingly adjust the city›s air moisture. This technology has several advantages including less wastage of heating and cooling, purification of air, reduction of noise pollution, and most importantly energy consumption efficiency – factors that can help the stabilization of city life. Due to the improvement in the social, economic and environmental conditions, the development of green roofs have always been at the top of the agenda in advanced cities. Heat loss through the roof of the buildings is high and there is a lot of energy wastage in higher floors units. Therefore, the green roof is a solution for this problem. Green roofs by rising roofing layers, act as a thermal insulation and help control heat exchanges between the inside and outside of the buildings. In the present research, after recognizing that benefits of green roofs with this hypothesis that “green roof and how design of green roof have effective role in reduce heat transfer” with help of analysis software called ansys, three samples of conventional roofs, green roofs conventional and green roofs with special detail (fiber glass layers) analyzed and heat transfer comparative compared. Also, installed heat sensors to verify the thermal performance of green roofs for designed green roofs and simple ample of normal green roof, indicate optimization of designed green roof respect to normal green roofs, heat performance wise. With software analysis and laboratory samples, green roof compared to 50% less heat transfer rather conventional roof and green roof with fiber glass layers to 40% rather green roof conventional optimized. Shading and evaporative cooling plants and also the role of roof layers that all perform like insulation, have effective role in reduce heat transfer. In researched, methodology research related to the benefits of green roof is descriptive and qualitative approach. But in sectors related to software analysis, these had quantitative approach and analytical methodology.