Nocturnal Cooling Technology for Building Applications by Mardiana Idayu Ahmad & Hasila Jarimi & Saffa Riffat

Author:Mardiana Idayu Ahmad & Hasila Jarimi & Saffa Riffat
Language: eng
Format: epub
ISBN: 9789811358357
Publisher: Springer Singapore

4.4 Review of Works Carried Out by Researchers from 2000 to 2013

Starting in 2000s, the research on the nocturnal cooling systems began to diversify with emphasis on different climatic conditions. However, in hot and humid climate, these systems are not really effective due to the risk of moisture condensation as a result of high humidity levels. In order to hinder the moisture condensation, if water-based system is implemented, the temperature of cooling water should not be lesser than the air dew point temperature [42]. Feasibility of four configurations of roof radiator with different materials was investigated in [4] based on hot and humid climatic conditions of Thailand. A series of experiments were performed under clear and cloudy sky conditions during wet season. Radiator’s surface temperature, effect of thermal emissivity of materials, heat capacity, effect of clouds, effect of water condensation, effect of rain and night space cooling were studied. From their results, it can be concluded that nocturnal cooling seemed to be feasible under the studied climatic conditions of Thailand with the surface temperature of roof radiators ranged from 1 to 6 °C below ambient air temperature.

In another study, the performance of a water-based nocturnal cooling panel of 5.75 m2 area was simulated using TRNSYS computer code based on weather data in hot and humid climatic conditions of Thailand [13]. Results showed the temperature was reduced and able to achieve thermal comfort conditions. In relation to energy savings, the cumulative thermal load of the nocturnal cooling panel was found to be 38.4% less than the conventional system. In addition, there was a good potential to achieve cooling water of 25 °C in which at this temperature, moisture condensation from air on the cooling panel did not occur. Prommajak et al. [43] investigated the performance of air-based nocturnal cooling radiator plate installed in a house model in Thailand during rainy season. Results showed that the temperature difference between the radiative plate and ambient temperature under clear sky condition was higher than under cloudy sky condition. The temperature of the radiative plate was 5 °C less than the ambient temperature. An experimental investigation to examine long-wave radiation in hot and humid climatic conditions of Owerri, Nigeria for nocturnal cooling applications was carried out in [44]. A water-based thermal radiator with a flat mild steel plate coated consisted of high emissivity black paint was developed. The results indicated that a cooling power of 66.1 Wm−2 was achieved.

A study was carried out on the potential of solar collector as a nocturnal cooling device in [45]. A night cooling metal roof panel (transpired solar collector) which was modified to potentially cool buildings was tested at under clear night sky of summer conditions in Toronto, Canada. This was done by connecting the roof panel to ventilation fans that provided the cooling effect. The results showed, with the ambient air of 14.6 °C, the temperature of the roof panel ranged from 3.9 to 5.3 °C which was almost 10 °C below ambient. On the other hand, a

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