Design and Experimental Assessment of a Minaret Integrated Passive Cooling System Performance for Mosque Buildings in Hot and Dry Climates

Abstract

Energy efficiency and conservation in the building is becoming the focus in many countries. In countries with hot climatic conditions, space cooling in buildings consumes a large amount of fossil fuels derived energy with a negative environmental impact. Compared with other public buildings, Mosques are characterized by high consumption of energy per person. To reduce energy consumption for space cooling in buildings and provide human comfort, evaporative cooling technologies have been applied in many places of the world using different techniques and materials. For example, the applications of porous ceramics materials with evaporative cooling have been recently researched as a novel idea in this field. The aim of this research project is to determine the most effective form of the passive cooling of water evaporation in mosques in the hot, dry climate of the Kingdom of Saudi Arabia KSA. Part of this research, will be using Design builder software to perform simulation on a case study for a typical mosque building in KSA to demonstrate that the energy saving strategies as passive cooling was applied to reduce cooling load. The result shows the full potential for exploiting design and construction features for improving environmental and energy performance of existing mosque buildings, The reduction of building cooling load in various locations in the KSA including Hail, Dhahran and Abha comes to about 37%, 30% and 40%, respectively compared to an uninsulated unshaded typical base case mosque building. In this research, the design and integration of an evaporative cooling system into the envelope of a mosque, specifically the minaret, has been conducted, highlighting the construction forms, the purpose and location of various aspects of the mosque, and the evolving function of the minaret in modern mosques. Hence, the proposed design considers the cooler configuration, and the cooling specification of the building, together with the construction materials of both porous ceramic and synthetic materials in the form of grass mats. The ceramic materials are compatible with integration into the structure of the minaret, while the synthetic material offers a modular design and flexibility for integration in the structure. The investigated cool minaret tower concept is intended to operate on the principle of sub-wet bulb temperature in which the air is cooled and supplied into the occupied space without increasing its moisture. The thermal performance of the proof-of-concept minaret prototype was evaluated in the laboratory under controlled climatic conditions. The cooling minaret tower was operated in three modes of evaporative cooling: in terms of Direct Evaporative Cooling (DEC), Indirect Evaporative Cooling (IEC), and Dew Point Evaporative Cooling (DPEC).The three modes allowed for the adaptation of the cooling performance, according to the prevailing weather conditions. The findings of the experimental study of the thermal performance of the synthetic fiber grass mats for all three modes revealed an overall positive trend in terms of the physical principles of evaporating cooling as a favorable cooling mechanism at a high inlet air temperature and low humidity levels. It was found that the drop in temperature for the current three modes under similar various operating conditions, varied from 5.7-12.9, 5.2-10.2, and 5.1-10.3 oC for direct, indirect and dew point modes respectively. Moreover, with higher humidity air supply the cooling power and wet bulb effectiveness decrease. Increase in inlet dry air temperature leads to an increase in either effectiveness or air supply temperature. The DEC mode system achieved 20% better temperature drops than other indirect evaporative cooling modes. However, this might not be considered a significant difference if it fails to satisfy the cooling requirements of the space as effectively a