An experimental study of improving Solar chimney performance using Energy storage and Hybrid cooling system

Abstract

This paper presents an experimental study that took place in Al-Kut city in Iraq in September and October 2021 on a two-story building. The study was mainly conducted to evaluate three parameters namely: air change per hour (ACH), indoor temperature, and indoor relative humidity inside each floor. The dimensions of each story were (1×1×1) m3. The building was associated with a vertical solar chimney SC from the geographical south direction while from the north; the building was linked with a hybrid cooling system. The study involved two cases: the first case was when the hybrid cooling system was associated with the building, while in the second case the hybrid cooling system was separated. The work aimed to study the night ventilation by adding Paraffin wax as energy storage in the two cases and to evaluate the effect of the hybrid cooling system on the two-story building. Al-Dura Paraffin wax was used as a phase change material PCM that stores thermal solar energy in daylight times and discharges the energy at the night during the phase change process. Results showed that PCM affects ACH during the daylight period and elongates the hours of ventilation after sunset. Whereas, the improvement of the first case compared with the second case for the first floor was 16.67% and for the second floor was 38.63%. In the 1st case, the indoor temperature was reduced by 7 K, while in the 2nd case the increase was (0.4-1.25) K compared with ambient temperature. As for the indoor relative humidity, The improvement rate for the relative humidity for the first case was 50 % for the first floor and for the second floor, it was 46.4 % compared with the surrounding relative humidity. While the average RH increased by 7 % on the 1st floor and 4.5 % on the 2nd floor in the second experimental case. The night ventilation lasted for 4 hrs. after sunset in the 1st case and 6 hrs. in the 2nd case.