Field measurements of post-operation evaluation of daylighting and thermal comfort in hot and arid climates: A pilot study of three educational buildings on the Najran University campus in Saudi Arabia

Abstract

The average energy consumption of educational buildings is constantly increasing due to their reliance on information technology equipment, expanded occupancy to accommodate new academic programs, and increased use of lighting and cooling systems. This research aims to gather data on the performance of lighting and cooling systems, as they are the two largest energy consumption systems on Najran University campus. It also explores opportunities to optimize the energy efficiency of the buildings, and it attempts to determine the satisfaction of Najran University users with the two operation systems (i.e., lighting and cooling). The research methodology depended on on-site measurements and online surveys. The on-site day lighting measurements confirmed that the maximum daylight illuminance levels were less than 100 lux in most workplaces and exceeded 100 lux only in a few workplaces, which were adjacent to windows. In addition, the field measurements of indoor temperature are 14.3–25.33 °C, which is a little cooler than the thermal comfort range during the majority of the year. Furthermore, the results of the building user questionnaire revealed that 73.1 % of respondents expressed satisfaction with the natural light levels at their workplaces. Only 57.7 % of respondents confirmed their satisfaction with the workplace temperature. However, the energy-efficient use of air-conditioning and artificial lighting systems would require the systems to be more flexible and dynamic. This research recommends optimizing control systems of air conditioning and artificial lighting systems to be converted to intelligent operation systems. That change would facilitate achieving energy-efficient buildings and give individual users adjustment options to adjust the comfort settings in their workplaces.