ENERGY RECOVERY HEAT EXCHANGER PERFORMANCE IN BUILDING’S AIR CONDITIONING SYSTEM

Nowadays, the urbanity and industrial growth have led people to spend about 90% of their time in the buildings which result in high energy demand for optimal thermal comfort. The design in heating, ventilation and air conditioning (HVAC) industry need a very high attention in order to provide a good indoor air quality (IAQ) and consume less energy in term of cooling and heating process. The use of 100% fresh air in any HVAC systems is necessary, and due to this reason cooling and heating load in conventional HVAC system consume large amount of energy especially in hot and humid region. In this project, the thermal performance of a Z shape enthalpy heat exchanger utilizing 70gsm Kraft paper as heat and moisture transfer surface has been investigated. Effect of different inlet air humidity ratio conditions on the heat exchanger effectiveness and on the energy recovered by the heat exchanger have been the main focus of this investigation. A typical air conditioning cooling coil which incorporates an enthalpy heat exchanger has been modeled for tropical climate. Under test conditions, results have shown that the latent effectiveness and the moisture resistance coefficient have strong dependency on the inlet air humidity ratio. Moreover, the latent effectiveness has been found to be strongly dependent on the moisture resistance coefficient rather than the convective mass transfer coefficient. Finally, annual energy analysis for Kuala Lumpur, Dubai, Miami, Rome and Sydney weather conditions have also shown that a significant amount of energy can be recovered since the Z shape enthalpy heat exchanger utilize the room exhaust air to pre-condition the ambient fresh air.