I received the following response from CanmetENERGY about WATSUN solar collector test data inputs and thought I'd share it with the group to follow up my recent post.

"The equation you refer to Q = Area ((A + B dT) Akt H - (C + D dT) dT - E) is for glazed collectors where A, B, C, D and E are test parameters, Area is the area of the collector, Akt is the incidence angle modifier, H is the incoming solar radiation, dT is the temperature difference between the collector inlet and ambient air.

Typically, glazed collectors do not require the B & E coefficients (leave them as zero). If you do not have the second order coefficient D set it to zero as well.

A = Fr (tau alpha)
B = 0
C = Fr UL
D = Fr UL_T
E = 0."

Brian Turner PE, CEM, LEED AP BD+C
Mechanical Engineer

CLARK NEXSEN