Improving Energy Efficiency in Building to Net Zero Energy Building : A Case Study Standard Government Office Building

Abstract

The objective of this study is to increase the energy efficiency in the standard type of government office building, which has been built in many places, by reducing the energy consumption to net zero energy consumption. The government office building has 4 floors with a total area of 7,020 square meters, divided into 2 buildings: (1) office section and (2) canteen with a meeting room at the top floor. The air-conditioned area is 1,295 square meters in total. This study was conducted through a computer program called BEC (Building Energy Code) version 1.0.6 which is developed for checking the consistency of the building model towards the standard of energy conservation in the building by Thailand Ministry of Energy.
According to the energy conservation standards from the Ministry of Energy guidelines, the Net Zero Energy Building can be archived by: (1) using 50 mm. fiberglass insulation with a density of 32 kilogram / cubic meter (kg/m3) in a solid wall, (2) using 6 mm. green reflective glass with 0.41 heat transmission value (SHGC), (3) adding a 25 mm thickness glass fiber insulation with density of 32 kg/m3 to the rooftop, (4) changing the lighting system to LED, (5) improvement of the air conditioning system, and (6) using solar energy panels with 17.1% efficiency as a renewable energy.
In this case study, the selected building has the total energy consumption of 209,091.33 kWh/year before the improvement, and reduced to 94,963.32 kWh/year after the improvement by improving solid and translucent wall, roofing, air-condition system and lighting system. The total energy consumption is reduced by 114,128.01 kWh/year (54.37%). The solar panels can produce a total energy of 147,713.84 kWh/year. Including improvement guidelines and use renewable energy from solar panels Making the overall energy consumption in the building to net zero energy. The payback period is 14.39 years with 4.87% rate of return.