A longitudinal analysis of energy consumption data from a high performance building in the tropics

Abstract

With the use of computer-aided tools, design of high-performance buildings is becoming the de facto industry practice. While reliability and ingenuity of computer simulation models is debated on one hand, continuous measurement and verification of building performance over a long-term is embraced as an alternative solution. The goal of this study is to assess the energy performance of a state-of-the-art high-performance building design in the tropics. Longitudinal and high-fidelity energy consumption data from the high-performance office building (3for2) is presented and analysed for this purpose. The approach to energy-performance assessment presented in this study has two parts. The first part is performance verification which entails using two-years of detailed energy-use data to validate building’s estimated annual energy-use, determined using short-term (i.e. first 100 days of building energy-use) data. Thus, recalibrating the building’s baseline energy performance. The second part is performance benchmarking which entails comparing target building’s energy performance against their peers. Thus, verifying the original classification of 3for2 building design as high-performance, by comparing normalized annual building energy-use against national benchmark statistics. The results and analysis based on long-term measurements help assess several key building performance measures of the 3for2 office design. Firstly, it verified the baseline energy-use is 81.1 kWh/sqm/yr as compared to 77 kWh/sqm/yr estimated based on short-term data. Secondly, several positive energy-saving interventions collectively lowered energy-use to 67.7 kWh/sqm/yr, and thus improve energy-performance by approximately 16% over the baseline. The relevant interventions implemented in 3for2 design are CO2-based demand control ventilation, occupant-centric controls and low-lift vapour-compression chiller. Finally, it demonstrated approximately 40% improved energy performance over other similar buildings in the tropics. Thus, the lessons learnt from longitudinal study help conclude that 3for2 is one of the most energy-efficient office building in the tropics. In addition, this study also exemplifies the role of middleware in making building designs not only high-performing, but also verifiable continuously in long-term throughout building’s life cycle. Overall, this concludes that truly realising high-performance buildings in future lies in not only integrating low-energy architecture and building systems, but also closing the feedback loop by integrating appropriate energy-saving interventions through high-fidelity data infrastructure.