Thermal Engineering

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Browsing Thermal Engineering by Subject "Adsorption, CaCl2"

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    Design and Development of a Solar Powered Cooling System to Harness Potable Water from Humid Air (A case study in Semi-Arid zones of Ethiopia)
    (Addis Ababa University, 2019-05-14) Gudeta, Wegissa; Abdulkadir, A. Hassen (PhD)
    Water shortage is very noticeable in semi-arid parts of Ethiopia where there is hardly any freshwater source at all. Currently, the most interesting method of getting sustainable alternative potable water by harvesting humid from air is continuously under research around the globe. This study was to quantify water from humid air as one of alternative sources using a solar energy prototype targeting semi-arid zone where predominantly pastoralists are living. This paper presents collection of humid air as sand bed introduced to atmosphere at night and a solar thermal regenerative process during day time then extract water from the system. The main objective of this thesis is to design and manufacture the prototype. The experimental setup consists of composite materials: calcium chloride and river sand as well as the glass box enhancing of capturing moisture from air and facilitate regenerative process. It is obvious that semi-arid has a hot temperature in day time, whereas sand bed is actually cooled at night. Hence, the two windows on the prototype introduce the ambient humid air to pass on the sand bed where the humidity will start adsorb. Whereas the solar glass box is exposed to solar radiation and internal temperature become increase where the evaporation and condensation has begun, the water drops will slide over the inner surface of solar glass and finally collected into the jar through the condensate trough. Due to weather climates similarity of Yabello and Adama, testing was done at Wind Farm Electrical Station -1, Adama. The result of one day experiment showed that moisture was collect on the sand bed during night and evaporation also successfully collected on the inner surface of the glass. Testing has been performed after good preparation at Adama wind farm Electric station-1for day and result shows that promising because water condensation on inner surface noticed. But, the numerical result and experimental result did not agree. Low production rate may be the consequence of air leakage, low of humidity amount in the air and low solar radiation intensity. After observing the test result for the effectiveness of the prototype further modification is recommended.