Reducing Air-Conditioning Load by Using an Insulating Material in Iraq as a Case Study (Experimental and Numerical)

Abstract

This paper has studied different types of walls using constant interior and exterior finishing materials (thermostone, 200-mm thick (A); fired clay bricks, 240-mm thick (B); hollow concrete blocks, 200-mm thick (C); solid concrete blocks, 140-mm thick (D); and limestone, 200-mm thick (E)) due to the availability of many different types of building materials in Iraq and the lack of control over the best use to demonstrate how each of these materials affects a building's insulation to deliver the appropriate levels of comfort and achieve the greatest possible reduction in the electrical energy needed for air conditioning. A unique chamber was created for performing the actual trials on such walls in their natural environment, which was the climate of the city of Baghdad (zip code 10016, 33° N latitude, 44° E longitude). The tests have been done both in their current state of operation and with the addition of thermal insulation (60-mm thick microfiber glass insulation material). The values for electricity consumption by a wall without insulation are 92, 121, 199, 148, and 138 kW/m², in cases noted as A1, B1, C1, D1, and E1, respectively. However, when the insulator is used, the values become 58, 63, 51, 100, and 92 kW/m² for the cases noted as A2, B2, C2, D2, and E2, respectively. The percentage reduction in electrical energy consumed by the air conditioner used within the room with and without thermal insulation has been recorded in the range of 50%–65% and 25%–60%, respectively. Depending on the model used, and compared with the traditional model, the saving difference with and without insulation was 15% and 35%, respectively. The best case is C2, because it has no effect on the room's interior area. Also, the cooling load was less than in other cases; it was 51 kW/m² and had the highest building electrical savings, which are 65% when taking the wall in case C1 as a reference.