Characterisation study and refinements of an enhance indoor airflow device

• Main Author: Choi, Cheng Yang.
• Other Authors: Lye Sun Woh
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/54035
• Institution: Nanyang Technological University

This final year project had been carried out by the author throughout his last academic year with an aim to improve cooling effect of air flow. The author approached an alternative way to lower down the air temperature by transferring heat from air flow to water and evaporating water to water vapor. This cooling method is known as evaporative cooling, which chill air flow temperature by vaporizing water and increasing relative humidity of the air flow. The device is attached to window type air conditioner. The air conditioner theoretically cooled and dehumidified the air flow at the same time. The aim of this design is cooling the outflow air from the air conditioner by slightly increasing the relative humidity of the air flow. The device is designed to maximize rate of evaporation by transferring heat from air flow to water on the surface of sponges. The air flow was cooled when it passed over the wet sponges zone that were slotted in between the channel. Closed system experiment was conducted to study further cooling of circulating air. The air flow was successfully being cooled down about 2.5℃ by activating fan mode of the air conditioner by using sponge type 1. Performance of using Type 1 sponge is better than type 2 sponge because it has rougher surface, which mean has larger exposure surface area for water evaporation. The performance increase when surface area for evaporation increase by increasing the length of sponge inside the channel. Humidity is one of the factors would affect the effectiveness of cooling. The sponge can cool down temperature by 2.5℃ in both open system and beginning of the closed system. However, effectiveness of cooling decrease sharply after the air is circulated in the closed system, only 0.3 to 0.5℃ difference before the air flow pass through the wet sponges zone. Closed system increases the humidity ratio of air flow bring down the effectiveness of water evaporation. The cooling ability of sponges by varying the inflow air temperature in open system and several effective cooling ranges have been determined. The outflow air temperature doesn’t represent the temperature of total air flow.