Question

Create a “clear sky insolation calculator” for direct, diffuse, and reflected radiation using the spreadsheet shown in Figure 4.26 (textbook) as a guide. Confirm that it gives you 859 W/m2 under the following conditions: August 1, 300 latitude, tilt 400, southwest facing (-450), 3:00pm ST, reflectance 0.2. Use the calculator to compute clear sky insolation under the following conditions (times are solar times):

a) January 1, latitude 400, horizontal insolation, solar noon, reflectance = 0

b) March 15, latitude 200, south facing collector, tilt 200, 11:00am, p = 0.2

c) July 1, latitude 480, south east collector (azimuth 450), tilt 200, 2:00pm, p = 0.3

Answer 1

Question needs a little modification

a) January 1, latitude 40⁰,horizontal insolation, solar noon, reflectance = 0

Answer : 463 W/m²

b) March 15, latitude 20⁰, south facing collector, tilt 20⁰, 11:00am, ρ = 0.2.

Answer : 1035 W/m²

c) July 1, latitude 48⁰, south east collector (azimuth 45⁰), tilt 20⁰, 2:00 pm, ρ = 0.3.

Answer : 744 W/m²