Experimental analysis of a humid fiber as an indirect evaporative cooling device against roofpond and gunny bags in a hot sub-humid climate

Type Working Paper
Title Experimental analysis of a humid fiber as an indirect evaporative cooling device against roofpond and gunny bags in a hot sub-humid climate
Publication (Day/Month/Year) 2016
ABSTRACT: In Mexico, the major proliferation of housing is the social housing. This type is built the same way for any
climate and orientation without a real analysis of the context. Its configuration, the roof may come to influence up to
two thirds in the conditions within the housing.
Effectiveness of the roof pond (RP) to reduce the temperature within the spaces has been demonstrated in many studies.
To achieve greater efficiency, certain conditions such as earnings avoid sunlight (shading), roof with high thermal
conductivity (steel) and a thickness of water over the entire roof (pond) must be met. In the reality of our cities, would
involve modifying more than 20 million households because roofs are made of reinforced concrete with a slight slope
to drain rainfall and would require adding a superstructure for shade.
In this paper, a humid fiber (HF) is proposed as a device of easy applicability in existing homes. This device is compared
experimentally with the roofpond and with a transition device between these two called floating fiber (gunny bags, GB).
The objective was to demonstrate that the proposed device is as efficient as the roofpond and the floating fiber with the
advantage of being readily applicable to any already built homes.
Four experimental modules with proposed devices and a reference module (RM) were monitored. Observed variables
were: inside-outside dry-bulb temperature and inside mean radiant temperature. They were logged for a week in two
different seasons representative of the region: hot sub-humid and hot humid. Operative temperature within the modules
was calculated from the observed values and were contrasted against outside dry bulb temperature and the operative
temperature of a reference module without modification.
Results show a decrease in the maximum operative temperatures of the three devices for both seasons. For hot subhumid
season, the temperature decrease was 3.6 K, 3.1 K and 3.0 K for RP, GB and HF respectively. To the hot humid
season, the temperature decrease was 1.5 K, 1.7 K and 1.4 K for RP, GB and HF respectively.
Effectiveness of the proposed device was demonstrated by maintaining OT differences with RP and GB under 1.9% and
0.1% for sub-humid season and 0.5% and 1.1% for humid season respectively.
In conclusion, advantages of the proposed device are that can be placed on reinforced concrete roofs regardless the
slope thereof and without an additional structure that shades the roof or support the overweight, allowing use if

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