M. Ahmadzadehtalatapeh

The empirical study of a four-row heat pipe heat exchanger to predict the year-round energy recovery in the tropics:

The effect of heat pipe heat exchanger on the heat recovery was studied in the tropics. The performance of the heat exchanger was monitored during the one week of operation (168 h) to find out the performance characteristic curves. Three coil face velocities namely, 2, 2.2 and 2.5 m/s were tested and the temperature of return air was controlled at 24°C. The relevant empirical equations were then employed for the hour-by-hour prediction of the energy recovery by the heat pipe heat exchanger for the whole year. The impact of inside design temperature on the heat recovery by the heat exchanger was also studied. The thermal performance of the heat pipe heat exchanger was simulated based on the effectiveness-NTU method and the theoretical values were compared with the experimental data. Practical application : Performance improvement of the heating, ventilating and air conditioning systems is a challenge to the designers. The results obtained from this research work could serve as a practical guide for engineers who are intending to use heat pipe heat exchangers in the heating, ventilation and air conditioning systems operating in tropical climates. Engineers and researchers have the potential to use the recommended empirical performance equations to examine the impact of heat pipe heat exchangers on the performance of the current air conditioning systems. Moreover, these empirical performance equations enable the year-round operating effect of heat pipe heat exchangers on energy savings to be predicted realistically.

Performance Analysis of a Heat Pipe Heat Exchanger Under Different Fluid Charges

An experimental study was conducted on the effects of the amount of working fluid on the performance of a two-row copper-R134a heat pipe heat exchanger at the air side. The heat pipe heat exchanger operates in the horizontal configuration, and five different fluid charges were studied to cover the underload and overload cases. Moreover, the calculated outlet temperature of the evaporator side, obtained from the heat exchanger simulation, was compared with the experimental results. Based on the present study, it was found that the optimum performance of the copper-R134a heat pipe heat exchanger can be achieved at a fluid charge slightly exceeding the amount required to saturate the wick.

Empirical Study of an Air-to-Air Heat Pipe Heat Exchanger in Tropical Climates

Abstract This article presents the empirical study of a heat pipe heat exchanger that was directly experiencing the ambient tropical air in its evaporator section. The performance of the heat pipe heat exchanger was monitored during two weeks of operation to determine the performance curves. The temperature of return air was controlled at about 22°C as the representative temperature of inside air, and a face velocity of 2 m/s on the heat pipe heat exchanger coil was established for this purpose. It was found that for the present investigation, the heat pipe heat exchanger can pay for itself in 1.5 years.