Aluminium plate painted flat black (solar absorptivity 0.98 and emissivity 0.97) Length of absorber plate is...
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?
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Aluminium plate painted flat black (solar absorptivity 0.98 and
emissivity 0.97)
Length of absorber plate is...
An unglazed flat plate solar water heater is orientated perpendicular to the sun such that the in...
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...
12.62 Two plates, one with a black painted surface and the other with a special coating (chemical...
12.62 Two plates, one with a black painted surface and the other with a special coating (chemically oxidized copper) are in earth orbit and are exposed to solar radiation. The solar rays make an angle of 30° with the normal to the plate. Estimate the equilibrium temperature of each plate assuming they are diffuse and that the solar flux is 1368 W/m2. The spectral absorptivity of the black painted surface can be approximated by αλ = o.95 foros λ oc...
Determine the overall heat transfer coefficient (UL) for a Flat Plate Solar Collector inclined at 45...
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...
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...
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?...
A flat-plate solar collector is used to heat atmospheric air flowing through a rectangular channel. The...
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. Consider an opaque, horizontal square plate (Im by 1m) with an electrical heater on its backside. The front side is exposed to ambient quiescent air that is at 20° C, solar irradiation (from...
1. Consider an opaque, horizontal square plate (Im by 1m) with an electrical heater on its backside. The front side is exposed to ambient quiescent air that is at 20° C, solar irradiation (from sun at 5800° K) of 600 W/m2, and an effective sky temperature of -40° C. The plate surface temperature is kept at Ts 60 C (at steady state condition). Calculate natural convection heat transfer coefficient from the plate. (10 points) What is the electrical power (W/m2)...
The roof of a minivan can be approximated as a flat plate, 2-m wide and 3.5-...
The roof of a minivan can be approximated as a flat plate, 2-m wide and 3.5- m long. The sun beats down on the roof such that the net solar radiation absorbed is 350 W/m2. If the ambient air is 32 ºC, the car is moving at 100 km/hr, and the inside surface of the roof is heavily insulated, determine the steady-state temperature of the roof (in ºC). Ignore heat loss via radiation emitted from the roof to the surrounding.
An aluminum plate with a thickness of L=5 mm is mounted in a horizontal position, and...
An aluminum plate with a thickness of L=5 mm is mounted in a horizontal position, and its bottom surface is well insulated. A special, thin coating (with emissivity and solar absorptivity of 0.25) is applied to the top surface. The density ρ and specific heat c of aluminum are known to be 2700 kg/m3 and 900 J/kg · K, respectively. Consider conditions for which the plate is initially at a temperature of ??????=25 °C and its top surface is suddenly...
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...
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...
The roof of a minivan can be approximated as a flat plate, 2-m wide and 3.5-m...
The roof of a minivan can be approximated as a flat plate, 2-m wide and 3.5-m long. The sun beats down on the roof such that the net solar radiation absorbed is 350 W/m2. If the ambient air is 32 °C. the car is moving at 100 km/hr, and the inside surface of the roof is heavily insulated, determine the steady-state temperature of the roof (in °C). Ignore radiation emitted from the roof. T32°C T 350w Assuming T, *45oC. Tlm-32+45)/2...
12.62 Two plates, one with a black painted surface and the other with a special coating (chemically oxidized copper) are in earth orbit and are exposed to solar radiation. The solar rays make an angle of 30° with the normal to the plate. Estimate the equilibrium temperature of each plate assuming they are diffuse and that the solar flux is 1368 W/m2. The spectral absorptivity of the black painted surface can be approximated by αλ = o.95 foros λ oc...
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?...
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. Consider an opaque, horizontal square plate (Im by 1m) with an electrical heater on its backside. The front side is exposed to ambient quiescent air that is at 20° C, solar irradiation (from sun at 5800° K) of 600 W/m2, and an effective sky temperature of -40° C. The plate surface temperature is kept at Ts 60 C (at steady state condition). Calculate natural convection heat transfer coefficient from the plate. (10 points) What is the electrical power (W/m2)...
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...
The roof of a minivan can be approximated as a flat plate, 2-m wide and 3.5-m long. The sun beats down on the roof such that the net solar radiation absorbed is 350 W/m2. If the ambient air is 32 °C. the car is moving at 100 km/hr, and the inside surface of the roof is heavily insulated, determine the steady-state temperature of the roof (in °C). Ignore radiation emitted from the roof. T32°C T 350w Assuming T, *45oC. Tlm-32+45)/2...
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