Sensitivity analysis and energy conservation measures implications

Electricity use characteristics of 10 air-conditioned office buildings in subtropical Hong Kong were investigated. Monthly electricity consumption data were gathered and analysed. The annual electricity use per unit gross floor area ranged from 233 to 368 kWh/m2, with a mean of 292 kWh/m2. The ranges of percentage consumption for the four major electricity end-users – namely heating, ventilation and air-conditioning (HVAC), lighting, electrical equipment, and lifts and escalators – were 40.1–50.7%, 22.1–29%, 16.6–32.9% and 2.2–5.3%, respectively. Ten key design variables were identified in the parametric and sensitivity analysis using building energy simulation technique. Analysis of the resulting influence coefficients suggested that indoor design condition (from 22 to 25.5 °C), electric lighting (a modest 2 W/m2 reduction in the current lighting code) and chiller COP (from air- to water-cooled) could offer great electricity savings potential, in the order of 14%, 5.2% and 11%, respectively.