Experimental Investigation of Energy Transfer in the Inflatable Greenhouse

Abstract

A transparent plastic-covered model greenhouse built without vegetation was tested under various operating conditions to determine the relative magnitude of its energy fluxes, namely, hot air heat and solar energy inputs, surface and ground losses as well as its efficiency.It is established that surface or membrane losses are quite comparable to the energy inputs and even larger than either input under certain operating conditions. The efficiency is found to be generally below 50% and is particularly low at high solar intensities, dropping to a low of 10% under such conditions.The Reynolds Number and a new Solar Parameter characterizing the mass flow rate of hot air injection and the rate of solar energy transmission into the greenhouse, respectively, are found to have a very significant influence on greenhouse performance. Notably, membrane losses are observed to increase remarkably with either increasing Reynolds Number or rising Solar Parameter.