Solar radiation is incident on a flat-plate collector at a rate of 450 W/m^2. The product of transmissivity and absorptivity if 0.85, and the heat loss coefficient of the collector is 4/5 W/m^2 C. The ambient air temp is 10 C. The collector temperature at which the collector efficiency is zero is
(A.) 95 C (B) 104 C (C) 112C (D) 87C (e) 73C
Solar radiation is incident on a flat-plate collector at a rate of 450 W/m^2. The product...
Problem 3: The specifications of a flat-plate collector is as follows: τ = 0.88, α 0.97, U = 1.3 Btu/h ft2 °F. The heat removal factor for the collector is 0.92, the solar insolation is 210 Btu/h ft2, and the ambient air temperature is 60°F. Determine (a) the collector efficiency if the water enters the collector at 115°F and (b) the temperature of water at which the collector efficiency is zero. Take the incident angle modifier to be 1
Problem...
Aluminium plate painted flat black (solar absorptivity 0.98 and emissivity 0.97) Length of absorber plate is 1.2 m, width of absorber plate w = 0.8 m, Ambient air temperature = 25°C, effective sky temperature = 10°C, solar radiation rate = 600 w/m2. Calculate the temperature of the absorber plate?
The front surface of the glass cover of a flat plate solar collector of dimensions 1 m x 1 m has a temperature of 40°C. The collector loses heat by convection to atmospheric air at temperature 14°C. For a wind speed of 5 m/s blowing along and parallel to the glass cover, determine the rate of heat loss by convection. Calculate the net heat loss from the glass cover due to radiation exchange with blackbody surroundings at temperature 7°C if...
Determine the overall heat transfer coefficient (UL) for a Flat Plate Solar Collector inclined at 45 degrees to the horizontal and facing south. The average ambient temperature for the day is 20 degrees C and the observed glass and absorber plate temperatures are 45 degrees C and 69 degrees C respectively. The system is provided with 6 cm thick insulation (glass wool, k = 0.04 W/m degrees C) at the bottom. The air space between the absorber plate and glass...
A flat-plate solar collector is used to heat atmospheric air flowing through a rectangular channel. The bottom surface of the channel is well insulated, while the top surface is subjected to a uniform heat flux 96,which is due to the net effect of solar radiation absorption and heat exchange between the absorber and cover plates. W Transparent cover plate Absorber plate Rectangular channel Air Tmi, m Beginning with an appropriate differential control volume, obtain an equation that could be used...
1. A glass plate is used as a cover in a flat plate solar collector. The transmissivity of glass is zero in the entire wavelength except in the band of 0.4 < a <3.0 um, where the value is 0.8. Assuming the sun to be black body at a temperature 5800 K, determine the average hemispherical transmissivity of glass over the entire wavelength range.
please show me how I can finds the answers of these two
examples
Example 1: Design of a Solar Heater (Black bodies: no convection) A square flat plate collector is exposed to solar radiation from both the sides. The exposed surface of the plate has an absorptivity of 1.0 for solar radiation. On a clear summer day on the earth's surface the solar radiation flux is approximately 1140 W/m2 and the surrounding air temperature is 25oC. Determine the surface temperature?...
Could someone help me with this question please as I am kinda
lost as in how to do these type of questions
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a) Draw a diagram of a solar hot water system and discuss the functions of its [5 marks For the solar collector, analyse the solar radiation heat gain and heat losses through different modes of heat transfer. How is the heat transfer rate to the water per unit area of the collector calculated? b)...
The solar radiation incident on the outside surface of an aluminum shading device is 1300 W/m2 . Aluminum absorbs 10% of the incident solar energy, and dissipates it by convection from the back surface and by combined convection and radiation from the outside surface. The convection heat transfer coefficient is 10 W/m2 ·K for both surfaces, and the ambient/surrounding temperature can be taken 20 °C for both convection and radiation. Assuming that the aluminum shade has a uniform temperature, determine...
An unglazed flat plate solar water heater is orientated perpendicular to the sun such that the incident radiation reaching the plate is 1100 W/m2. The plate has a semi selective coating such that the plate absorptivity and emissivity is equal to unity for all wavelengths up to 2µm, and 0.13 for all λ > 2µm. Coolant flowing in the collector tubes removes heat at such a rate as to maintain the plate temperature at 80°C. Considering the sun to be...