Air Handling Unit

Listing ID #3170746

In this write up, an energy-saving device is introduced into the air-handling unit (AHU). Due to increases in energy costs, energy saving devices or systems have become the new preferred trend in tropical countries. A primary cooling coil system is incorporated into the AHU to recycle the condensate water in order to achieve energy savings. The warm outside fresh air is drawn through the primary cooling coil to recover the latent heat of condensate water. The large temperature gradient between the warm fresh air and condensate water enlarges the amount of energy recovered. This system is well applicable to primary AHU which serves primary air to the airconditioning system. The cost of installing the device is negligible but in returning long term saving. Furthermore, the de-cooled condensate water can be drained off through non-insulated drain pipe. The idea generation is discussed in the introduction. Chapters 2 and 3 describe the preliminary calculation of the energy saving percentage. Chapter 4 shows the detailed theoretical study of the development of the energy saving system. This shows the viability of the idea. Chapter 5 will recommend the design of the primary cooling coil configuration to achieve the desired cooling effect and energy saving strategy. Lastly, the conclusion of the whole study is presented.
In tropical countries such as the United Arabia Emirates (UAE) and Malaysia, the climate is always hot and highly humid throughout the year. Lots of energy is consumed for Air-Conditioning and Mechanical Ventilation (ACMV) systems.
For buildings such as hotels and hospitals, energy is used to cool down the fresh air in the primary AHU and pumped into the building to achieve the internal air quality required. Due to the high humid climate, lots of condensed water is drained away as a by-product. However, the cooled condensate water actually consumes 2% of the total cooling load of the system on average. Here, we are studying the recovery of the condensed water in which the 2% energy can be saved. 2% of energy for a system running 24 hours a day can make a significant reduction for the operating cost.
The condensed water is first collected by the condensate drain pan below the main secondary cooling coil. Then, the collected condensed water is pumped into the primary cooling coil for the de-cooling process.
In order to maximize the energy recovery, a primary cooling coil is recommended to be installed at the fresh air intake opening of the AHU where the temperature gradient between the air outside and condensate water is greater, rather than at the side in which air returns or at the mixing plenum.