Low-Exergy Building Using Renewable Energy for Indoor Thermal Comfort: Experimental Study and Thermodynamic Analysis

Building sector consumes about 30-35° of the total energy consumption in the world. Renewable energy resources have a huge potential for building cooling with low energy consumption. One of the attractive techniques that are used to utilize the renewable energy for building cooling is low-exergy systems. Low-exergy systems use low valued energy with low exergy destruction for building thermal comfort. In this study, an experimental model of low-exergy system based on combination of wind catcher and solar chimney was incorporated into a room located in Khartoum, Sudan. The results showed that the presented model could achieve indoor temperature of 27-29°C which is within the thermal comfort zone of Khartoum (25-28°C). However, the system revealed non-comfortable indoor relative humidity (70-79°) since the thermal comfort of Khartoum is (<70%). The thermodynamic analysis revealed that the energy consumed in the system was 120 kW with exergy destruction of 0.194 kW, showing low-energy source utilization with low exergy consumption for the cooling purpose. However, the cooling load was much less than the energy consumed by the system (21 W), showing the non-economic aspect of the proposed method. Therefore, humidity control, non-evaporative cooling and optimal design where recommended as future research directions.