KING FAHD UNIVERSITY OF PETROLEUM & MINERALS Dhahran, Saudi Arabia Mechanical Engineering Department ME 439: SOLAR ENERGY CONVERSION Special Assignment (122) Using EES Due Date: May 15, 2013 The following is a simulation problem given as a semester project. A flat-plate solar air heater, as shown in Figure 6.14.1 (b), is made up of a GI absorber plate and single glass cover with KL = 0.0125. The following data is given: Location of collector -Dhahran (26.3o N, 50.2o E) Date -August 11 Length of collector -2.05 m Width of collector -1.05 m Length of absorber plate -2.0 m Width of absorber plate -1.0 m Air Channel depth -15 mm Plate-to-cover spacing -25 mm Thermal conductivity of plate -35 W/m oC Air flow rate -200 kg/h Air inlet temperature -50oC Absorber Plate/back plate emissivity -0.95 Cover emissivity -0.88 Collector tilt -latitude angle (south facing) Refractive of glass relative to air -1.526 Surface azimuth angle -0o Back insulation thickness -50 mm Insulation thermal conductivity -0.04 W/m oC Edge thickness -25 mm
Climate and solar radiation data Solar time, in the hour ending at 6 am 7 8 9 10 11 12 Noon 1 pm 2 3 4 5 6 pm Insolation on horizontal surface, W/m2 33 176 389 606 789 920 992 983 901 754 556 333 121 Ambient temp., oC 33.5 34.9 35.3 37.7 40.6 42.7 42.7 43.3 42.5 41.9 41.2 40.6 38.9 Relative humidity, % 36 32 33 30 26 22 21 20 20 22 27 28 33 Wind speed, km/h 19 21 20 16 14 11 17 18 27 28 25 25 21 Calculate and tabulate the following results: 1. Total solar radiation incident on the collector 2. The absorbed solar radiation by the collector absorber plate 3. Collector heat-removal factor and overall loss coefficient 4. Air outlet temperature 5. The useful energy gain 6. The collector efficiency 7. The pressure drop across the collector How do the results change if the heat transfer surfaces in the air duct are roughened? Assume that because of the roughening, the convective heat transfer coefficient increases by 40%, while the friction factor is…