A flat-plate solar collector is used to heat atmospheric air flowing through a rectangular channel. The...
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 answer this question correctly and in detail 3.1A single-glazed air heating collector that has a flow channel behind the absorber that is 1.5 m wide, 3.5 m long, and 5 cm high. The mass flow rate of the air is 0.045 kg/s and the air inlet temperature is 45°C. The insolation on the tilted collector surface is 920 W/m and the collector effective ta is 0.87. When the ambient temperature is 12°C, the overall heat loss coefficient is 4.5...
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...
Problem 3: (35pts) Atmospheric air enters the heated section of a circular tube at a flow rate of 0.005 kg/s and a temperature of 30°C. The tube is of diameter D =60mm, and fully developed conditions with h = 30W/m2K exist over the entire length of L-4m. Take cp-1015 /kg.K 2 (a) (10pts) For the case of uniform surface heat flux at q"-1000W/m, determine the total heat transfer rate q and the mean temperature of the air leaving the tube...
For the collector geometry shown below and an inlet temperature of SO F, calculate the following parameters for this liquid flat plate design: 1) Useful energy collection, 2) Outlet temperature, 3) Collector efficiency, and 4) Pressure drop A 50% ethylene glycol solution flows upward through the collector at 0.25 GPM entering at the given temperature. The collector is mounted in a vertical position. Calculate the performance in Amherst, Mass. for the hour between 11 and noon on November 19- when...
A solar panel (5m x 2m) is used for heating domestic water. The absorbing panel has an absorbtivity of 0.93, a top-plate symmetry emissivity of 0.9, and a back-plate emissivity of 0.05. The transmittance through the glass top cover is 0.85. With a peak radiation of 700 W/m^2 the absorber temperature is 100° C and the top-cover is 60° C. if the all the absorber heat is transferred to the water which flows through ducts in the absorber with negligible...
3 (40 pts) An infinitely large plate of thickness 20 cm is insulated at the lower surface. Within the plate, heat is uniformly generated at a rate égen = 5 x 104 W/m2. The temperature of the air above the plate is known as Tair = (1 - sini z), where 1 = 3000 m and the origin of the coordinate system z starts from the upper surface of the plate. The physical properties of the plate: p = 7.9...
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...
PRINTER VERSION BACK NEXT RCES Supplemental Problem 7.001 A flat plate of width 1 m is maintained at a uniform surface temperature of T,-160°C by using independently controlled, heat-generating rectangular modules of thickness a 10 mm and length b 50 mm. Each module is insulated from its neighbors, as well as on its back side. Atmospheric air at 25°C flows over the plate at a velocity of 30 m/s. The thermophysical properties of the module are k5.2 W/m K, cp...
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?...