τα m S7.4 A general collector equation. Concentrating solar collector test data is sometimes expressed in a form that is

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τα m S7.4 A general collector equation. Concentrating solar collector test data is sometimes expressed in a form that is also applicable for flat-plate collectors: Q. F'(ta),[Kıq (0)G5 +K<«0)Ga] - (q + czu)(Tm - Ta) A dt - cz(T-T.)+ c Elwr - C5 CouG dt where F' is the collector efficiency factor and the appropriate temperature is Im = (Tin + Tout)/2. K0) and Ka@j) are the beam and diffuse incidence modifiers, c, through c are empirical constants, and u is the local wind speed. Elwr is the net incident infrared radiation on the collector from the ground and sky and is equal to 1 + cos B 1 - cos B Ezwr=014 ( Esky 2 2 where the sky emittance E sky is the term in the square brackets in Equation 3.9.2. If the two incident angle modifiers are equal and cthrough co are zero, then the equation reduces to Equation 6.17.5. If c, is nonzero, then the equation reduces to Equation 6.17.7. If wind speed is important, as it is in uncovered collectors, then cz and C are nonzero. Finally, if cs (an effective thermal capacitance) is nonzero, then it is possible to track the collector transients. Estimate the annual energy production of a concentrating collector in Pueblo, CO, oriented to track on a single east-west axis. The collector has the following characteristics: Tin = 80°C, m = 0.77 [kg/s], A= 5.38 [m²], L = 4.1 [m], F'(ta), = 0.590, Kaj) = 0, bo = 0.52, c, = 0.932 [W/m²K], C2 = Cz = C4 = 0, C5 = 2460 [J/m² K), C6 = 0.0125 [s/m]. Also estimate the annual energy production with Cş equal to zero. :- 1) = τα