The air handling units used in air-conditioning heat recovery methods and take advantage of external air temperature

İn the close past and nowadays all countries in the world are competing with each other to own energy. Our country imports energy to a large extent. The import of energy both increases the foreign indebtment and external dependence. Being dependent externally is a major obstacle for our country on the way to the total indepence. By means of this studying investor and academy were tried to get together. It was tried to show that investor in product-oriented purchases should see a product general sistem not just a product. Three different systems were developed. The AHU capacity was determined according to international norms. Three were heat recovery output temperatures and heating and cooling battery capasities, pump, boiler, chiller, fitment and etc. Were designed by calculating pressure loss. Material and labor cost were calculated by exemining every system separately. As a pruduct oriented, heat recovery system are more suitable for the general sytstem, despite the high cost. However, annualy operating cost in this system makes a significant difference. Also if add by-pass unit to the AHU and we utulize outdoor air temperature we can see how much energy we save on.