Controlling space humidity with heat-pipe heat exchangers

The performance of an existing 5 ton (17.6 kW) air conditioning system with an energy efficiency ratio, EER, of 8 has been simulated by retrofitting it with a heat-pipe heat-exchanger (HPHE) to improve cooling and dehumidification. Weather data for Dallas (ASHRAE, 1997) is used for this investigation. This investigation shows that by retrofitting an existing 5 ton (17.6 kW) air conditioning system with a HPHE, additional moisture of 0.297 1bm/min (0.134 kg/min) is removed from cooling coil. The additional cooling and dehumidification results in an increase in the performance by 96%, i.e., an increase in EER from 8 to 15.7. For the present investigation, a HPHE retrofit will pay for itself in less than a year. On the basis of this investigation it is recommended that HPHE may be used for improving dehumidification, reducing energy consumption and peak demand for air conditioning in the residential and commercial sectors. Work is currently underway to calculate the removal of additional moisture by using hourly weather data for a number of US cities.