Passive pre-cooling potential for reducing building air-conditioning loads in hot climates

The passive airside cooling capability of heat pipes operating under high-temperature natural ventilation airstreams was investigated in this study. Pure water was used as the internal working fluid to ensure the system remained sustainable in its operation. The physical domain included 19 cylindrical copper heat pipes assembled in a systematic vertical arrangement. Using the monthly temperature data of Doha, Qatar, as a case-study reference, the efficiency of the heat pipe model was analyzed at fixed inlet air velocities of 1 and 2.3 m/s. At a source temperature of 314 K, the results showed a maximum temperature reduction of 3.8 K for an external air velocity of 1 m/s. A cooling load of 976 W was achieved, indicating a heat pipe effectiveness of 6.4% when the velocity was increased to 2.3 m/s. Wind tunnel experimental testing was conducted to validate the findings. A good correlation was observed between the two techniques with error variations of 10% for velocity and 28% for temperature. The present work identified the potential of sustainable pre-cooling using heat pipes in natural ventilation airstreams for regions with hot and dry climatic conditions. The concept is currently under intellectual property protection (GB1321709.6).