Towards the improvement of thermal comfort in residential houses in Kampala City

Abstract

Climate change and global warming continue to present several difficulties. Buildings used for business and residences consume a lot of energy. Due to the rise in human comfort needs and services, this consumption significantly rises each year. As a result, the residential sector uses a large amount of energy globally. This necessitates a Net Zero Energy Building (NZEB) strategy that places a focus on bridging the energy supply and demand gap for renewable energy sources. Although NZEBs play important roles in smart cities' energy efficiency, the potential contribution of NZEB to Uganda's residential sector has not been adequately explored in the literature. This study aimed at creating a thermal comfort model for residential homebuilders to use when designing envelopes. The specific objectives included developing a NZEB model for Kampala city homes to increase their thermal comfort and validate the model, quantifying the thermal comfort needs of residential buildings using predicted mean vote (PMV) and predicted percentage of dissatisfaction (PPD), and suggesting considerations for designing homes in Kampala. ASHRAE 55 standard utilizing the Center for the Built Environment (CBE) tool. Results from the CBE tool revealed that the PMV of residential buildings in Kampala with elevated air speed during sleeping hours, or at night, was 0.48. Standard Effective Temperature (SET) = 27.7 °C, Dry Bulb Temperature (DBT) = 24.0 °C, PPD = 10%, Cooling effect = 3.5 °C and the Sensation is neutral. These results were validated on a python simulation whose results show a close relationship with the results obtained from the CBE tool. The study identified several crucial factors required when building in Kampala city. These included air temperature, radiant temperature, air speed, air humidity, thermal insulation, ventilation, windows and glazing, solar heat gain and thermal mass. The amount of energy needed to provide light, heat, or cool a given building depends on its location. According to the study, the factors that were considered when building these structures need to be reviewed for Kampala residents to enjoy living there. The study identifies better design technologies like, putting a cladding system with movable louvers, water saving in basement, use of natural ventilation, adopting an integrated building system, utilization of thermal mass and radiation cooling and heating panel system for residential structures.