Effects of Humidity in En-Suite Bathroom Residences to the Electricity Bill from Air Conditioner

Abstract

Energy Policy and Planning Office, Ministry of Energy, has showed the increased trend of electricity usage. Thailand’s high temperature and continuous expansion of the urban areas lead to the significant growth of electrical usage from air conditioners each year. The household economics and social surveys from 2007 – 2015 showed that the apartment and dormitory businesses have installed a great deal of air conditioners. Average electricity bill of residences with air conditioners installed are 3.5 times more than residences without air conditioners installed. The Dormitory Business Registration Data from Ministry of Social Development and Human Security in Bangkok showed that there were as many as 24,754 dormitories with air conditioners installed in 2018.

            Air Conditioners were designed based on Comfort Air Conditioning with as small energy usage as possible for optimum temperature, humidity, wind speed, and energy usage. This research aims to study the air conditioner’s Cooling Load which consists of Latent Heat and Sensible Heat. Apartment and Dormitory’s main source of humidity is the bathroom. As the bathroom is the main function of en-suite bathroom residence, occupying 15-30% of total room area, the bathroom usage (washing hands, showering, cleaning, etc.) will also transfer the humidity to the air-conditioned main area. This research collects temperature and humidity to calculate electricity bill by Psychometric Chart Method. The Psychometric Chart is used to obtain total energy which then converted to Latent Heat and Sensible Heat to calculate electrical usage and electrical bills from the air conditioner. The results are used as guideline for expense reduction for residents and electrical energy usage reduction for the country. The research shows that prevention of humidity from the bathroom could save electricity bill as much as 12%.