The transmissivity of E-W aligned models of a conventional and clerestory greenhouse under natural winter irradiance

Abstract

Computer model predictions of the winter light transmission characteristics of conventional symmetric-roofed and vertical south roofed (clerestory) multispans have been substantially verified by measurements on small glass models of the two multispan houses. Good correlations were found between the predicted and measured diffuse and direct light transmissions across a central span, after correcting for absorption by joints at the apices and troughs of each span. Errors at the extreme edges of the span still occur, however, but plausible explanations can be found for these. The average transmission difference between the two models over the winter period was found to be 4%, compared with a predicted value of 5%. Somewhat lower levels of direct and circumsolar radiation than expected may account for part of the difference.