Collectors complying with the ASHRAE 96-1980 and 93-1986 standards are modelled analogously to collectors complying with European standards. An overview of the main differences is provided below.<\/p>\n\n\n\n
The following applies to the efficiency:<\/p>\n\n\n\n
\\(\\eta(x) = \\eta_{0} + a_{1} \\cdot \\frac{P}{I} + a_{2} \\cdot \\frac{P^{2}}{I}\\)
where<\/p>\n\n\n\n
\\(P = \\ T_{i} – T_{a}\\)<\/p>\n\n\n\n
\\(T_{i}\\) = temperature of the fluid flowing through the collector<\/p>\n\n\n\n
\\(T_{a}\\) = ambient temperature
I = irradiance on collector surface<\/p>\n\n\n\n