saturs - Latvijas Lauksaimniecības universitāte

U. Iljins, I. Ziemelis The Optimization of Some Parameters of a Flat Plate Solar CollectorNumerical values of the parameters of the collectorNo. Parameters Unit of measure Numerical value NotesTable 11 L m 0.452 λ a W⋅(m⋅K) -1 283.0668027 Computed3 λ i W⋅(m⋅K) -1 0.039 Mineral wool4 λ W⋅(m⋅K) -1 74 Steel5 α r W⋅(m 2 ⋅K) -1 22.44213862 Computed6 α gl W⋅(m 2 ⋅K) -1 7.834448038 Computed7 α abs W⋅(m 2 ⋅K) -1 15.01922431 Computed8 δ 1 m 0.059 δ 2 m 0.000810 δ 3 m 0.0511 T 0o C 2012 Q W⋅m -2 62513 x 01 m 0.0514 x 02 m 0.215 x 03 m 0.3516 q 1 W⋅m -1 - 78.64782131 Computed17 q 2 W⋅m -1 - 83.43894 Computed18 q 3 W⋅m -1 - 87.2626894 Computedwhere- coefficients A I , A II , A III , B I , B II , B III are found by solving the system of linear equations (18);- coefficient A I is determined from equation (42) by using coherences (23), (34), (35), (38), and (39);k- coefficients A II and k BII are calculated from expressions (40) and (41);k- coefficient B III can be found from formula (43) by using coherence (26);k- particular value µ kis computed from expression (13).In order to verify the accuracy of the developed mathematical model, a special device has been made for theexperimental investigation. The solar collector was produced accordingly to the mathematical model and, insteadof the sun, an electric lamp of certain power was used. The temperature on the corresponding surfaces of the6050T, o C403020100L, m0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5Fig. 2. Comparison of the computed temperature on the surface of the absorber (uninterrupted line)with that obtained experimentally (points).74 LLU Raksti 12 (308), 2004; 67-75 1-18