Impact of Building Forms, Orientations and Envelope on Energy Performance of Office Building Based on the ASHRAE Standard 90.1-2016

Abstract

This research studied the effects of shape, building orientation and building envelope on the energy saving of office buildings according to AHSRAE 90.1-2016 standards, to create guidelines for building owners and architects in designing office building in order to be evaluated green buildings according to LEED v4. 1 criteria. The study began with a detailed survey of the design of 72 office building designs in Bangkok. The representative buildings then were determined to have an area per floor of 1,600 m2, a floor-to-floor height of 4 meters and a service core location in the center of the building's floor plan. There were 3 heights of building including 8 floors, 15 floors and 30 floors. The site location was set in Bangkok. All representative buildings were built into proposed buildings referring to the requirements of the Appendix G, ASHRAE 90.1- 2016 standard, by modifying various architectural elements with the proposed building, such as the direction of orientation, building envelope materials, window-to-wall ratio (WWR), lighting power density (LPD) and coefficient of performance (CoP) of HVAC systems. It has been found that the variables that most influenced the increase and decrease of end- use energy were the type and coefficient of performance ( CoP) of the HVAC system. The Variable Refrigerant Flow (VRF) system with a CoP value of 4.56 have an energy-saving percentage of only 9 percent compared to the baseline building while Centrifugal Chilled Water ( CHW) system with a CoP value of 7. 03 had energy saving percentage at 24 percent. The variables that least influenced the increase and decrease of end- use energy were the orientation of the building. In terms of other building envelope variables, such as WWR, opaque wall materials, and fenestration materials, affect directly to the increasing and decreasing of building energy. For example, a proposed building with a WWR value of 60% will cause the building to use more energy than a proposed building with a WWR% value of 40% because there is more fenestration area per opaque area, etc.