The study investigates the benefit of utilizing the waste water which washed the walkway of residential buildings to humidity the ventilation air that supplied to the building. The water will collect in a concrete channel section (100 * 100 mm) in contact with the wall of the building towards the drainage network. The side adjacent to the wall contains (5mm) diameter holes ending with an air gap located behind the external wall metallic finishing. The ventilation (environmental) air (naturally or forcibly) passes through the holes to the air gap through the holes. This causes the temperature to decrease and the moisture content of the air is increased. The moving air passes through the gap towards the environment through the openings at the top of the wall. The study is carried out Baghdad city (latitude 33.2 ° North) using two types of external finishing material (Aluminum sheets) reflector and plates coated with thermal dyes. Also, employed an air gap or an air gap with thermal insulation thickness (50 mm) placed behind the plate. As well as the case of the air gap is open to the environment during day and night or closed day and “open at night” with an exhaust fan that worked by solar energy. The results showed that in the case of the air gap behind the external finishing material with thermal insulation, the fan operates during the day hours of the day and the area (1 m2 ), the cooling load required during the summer is (306 kW-hr / m2-cooling season). While the cooling load of the common wall is (609 kW-hr / m2-cooling season. Thus, the savings rate is (49.8%) when used this technique.
Forced convective heat transfer in a vertical channel symmetrically heated with a constant heat flux, and packed with saturated porous media, has been investigated experimentally in the present work. The channel was padded with spherical glass of three diameter (1, 3 and 10 mm) in a range 0.0416 < (particle diameter / inner channel radius) <0.416. The experimental setup, using a copper tube as a packed bed assembly with (48 mm) inside diameter and (1150 mm) heated length with a constant heat flux boundary condition. The test section was vertically oriented with water flowing against gravity and packed with glass spheres (1, 3 and 10 mm) diameter respectively. The results show that local Nusselt number increased at 34% with increasing Reynolds number at 65% while increased at 11% with increasing heat flux at 71%. Heat transfer rate increase as the particle diameter increase at the range of (1 – 3) mm but decrease with increasing particle diameter at the range (3 – 10) mm. Pressure drop through channel minimize at 97% as porosity increase at 23%.Many empirical relations, obtained experimentally.
This paper presents experimental results of forced convection heat transfer and pressure drop across ( 12.5 * 12.5 * 100 cm ) square packed duct. The pad made of forty-eight metallic wrapping coil unit with (0.98 porosity ) and (26 W/m.°C thermal conductivity ). The local surface duct temperature and local heat transfer coefficient distribution, Nusselt number, pressure drop and friction factor were measured for heat flux (0.56 to 2.73 kW/m 2 ) ,Reynolds number (40339 to 54797 ) and three boundary condition of heat flux imposed on duct surface . It was found that Nusselt number increases as Reynold number, heat flux and number of duct surface exposed to heat flux increases. Nusselt number in packed duct is to be ( 1.2 , 1.19 ) times higher than the empty ducts at heating all surface and top & bottom surface of packed duct respectively. Many empirical relation between Reynold number, Nusselt number and pressure drop obtained in this study.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.