by Energy Research and Development Administration, Division of Solar Enegy, for sale by the National Technical Information Service in [Washington], Springfield, Va .
Written in English
|Statement||by K. R. Randall, M. M. El-Wakil, and J. W. Mitchell|
|Contributions||Mitchell, J. W., joint author, El-Wakil, M. M. 1921-, United States. Energy Research and Development Administration. Division of Solar Energy|
|The Physical Object|
|Pagination||viii, 50 p. :|
|Number of Pages||50|
Flat plate collectors with temperature of fluid not rising above 80 C. Concentrating collectors with temperature of fluid going above C. Pras ad, Byre gowdand Gn vti() cat ego rizd colltos as: Hydronic collector – Water as working fluid. Air collectors – Air as working : Gagandeep Singh Bagga, Sandeep Kumar. heating, power production, solidification process, solar collectors, energy storage devices, as well as natural phenomena. The physical phenomenon encountered in natural convection along a horizontal heated plate facing downwards is the same as the one observed along a horizontal cooled plate . Non-Darcian forced convection heat transfer over a horizontal flat plate in a porous medium of spherical particles has been studied experimentally. The flat plate collectors forms the heat of any solar energy collection system designed for operation in the low temperature range, from ambient to 60 or the medium temperature, form ambient to A well engineered flat plate collector is delivers heat at a relatively low cost for a long duration.
Consider a flat-plate solar collector placed horizontally on the flat roof of a house. The collector is m wide and m long, and the average temperature of the exposed surface of the collector is 42°C. Determine the rate of heat loss from the collector by natural convection during a calm day when the ambient air temperature is 8°C. Free convection, or natural convection, is a spontaneous flow arising from nonhomogeneous fields of volumetric (mass) forces (gravitational, centrifugal, Coriolis, electromagnetic, etc.): If density variation Δρ is caused by spatial nonuniformity of a temperature field, then a flow arising in the Earth gravitational field is called thermal. Flat plate collectors concentrating type collectors Absorber area is large. Absorber area is small. Concentration ratio is 1. Concentration ratio is high. It is uses both beam and diffuse radiation. It is uses mainly beam radiation. Application limited to low temperature uses suitable for all places as it can work in clear and cloudy days. The Grashof number range tested was 4 × 10 3 to × 10 5, and the aspect ratio (ratio of enclosure length to plate spacing) varied between 9 and The angles of tilt of the enclosure with respect to the horizontal w 60, 75 and 90 deg. Correlations are developed for both local and average Nusselt number over the range of test variables.
Horizontal Plate Isothermal Heated Natural Convection Equation and Calculator. Average heat transfer coefficient and plate temperature for an isothermal (constant temperature) heated horizontal flat plate's lower surface or a cooled plate's upper surface in a natural convection environment. N.M. Nahar, H.P. GargFree convection and shading due to gap spacing between an absorber plate and the cover glazing in solar energy flat-plate collectors Appl. Energy, 7 (), pp. , /(80) Example 1: Forced Convection and Flow Past a Horizontal Plate. Let’s consider the situation of modeling the flow past a horizontal flat plate with a length of 5 m, which is subjected to a constant and homogeneous heat flux of 10 W/m 2. The plate is placed in an airflow with an average velocity of m/s and temperature of K. Natural convection on a surface depends on the geometry of the surface as well as its orientation. 14‐1 in Cengel book lists these constants for a variety of geometries. Isothermal Horizontal Plate The characteristics length is A/p where the surface area is A, and perimeter is p. a) Upper surface of a hot plate.