The effect of input air properties on the efficiency of Heat Pipe Heat Exchangers (HPHE) in series used for the purpose of energy conservation in an air conditioning system has been investigated at pilot scale in this paper. Thermosyphon type heat pipes used in the heat exchangers have the duty of precooling the input air and conducting the heat to the processed stream by preheating it. HPHE is a heat superconductor that deals with few temperature gradients between evaporator and condenser sections and with no heat pump and no additional power. The main design parameters of this air conditioning system include mass flow, temperature and humidity, which affect heat transfer coefficient and efficiency of the HPHE. The experiments show that by using HPHE in an air conditioning system, with both methanol working fluid we will save in average around 9% of energy in the evaporator and 37% in the condenser of the HPHE and for methanol – acetone working fluid we will save 15% in the evaporator and 64% in the condenser. The significance of this paper is the use of two HPHEs in series which make them more efficient in contrast to a single HPHE. This framework has the ability to put different working fluids in the HPHEs, such as methanol and acetone utilized in this research.

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