ASSESSMENT OF AIR CHANGE EFFECTIVENESS AND THERMAL COMFORT IN A NATURALLY VENTILATED KITCHEN WITH INSECT-PROOF SCREEN USING CFD

Abstract

ABSTRACT Many dwellings in warm-humid climates attain a comfortable environment by natural ventilation. The opening of exterior windows for ventilation allows the entry of insects along with the breeze. As a remedy, occupants install insect-proof screens on windows resulting in reduced airflow into the interior. This study attempts to evaluate the air change effectiveness and thermal comfort in a residential kitchen with insect-proof screens. A kitchen with insect-proof screens on the windows is compared with a case without insect-proof screens. Numerical simulation was conducted using ANSYS Fluent 2019 R2. The insect-proof screen is modelled as a porous media. The air velocity and temperature measurements were validated by measurements in a real scenario. The presence of insect-proof screens reduced the air velocity inside the space by 82%. However, the airflow pattern in the case with screens was more uniformly distributed. The mean age of the air was considerably higher in the case with insect-proof screens, which in turn resulted in a reduced ACE. The presence of an insect-proof screen resulted in a Predicted Mean Vote (PMV) of 2.79 indicating a ‘hot’ sensation, whereas in the other case, the comfort vote is only 1.93 indicating a ‘warm’ sensation. The presence of insect-proof screens on windows reduced the air velocity and ventilation efficiency, contributing to increased thermal discomfort in the kitchen.