The effectiveness of duty cycling technique on air conditioning system during break period for comfort, energy and cost savings: A real case study in health center

This paper investigates the potential of duty cycling techniques for air conditioning (AC) systems in producing energy and cost savings and the impact on the indoor thermal environment, air quality, and environmental sustainability. The real case study concentrated on energy consumption practice during the break period between 13:00 to 14:00 in a lobby area of a Health Center. Site data measurements of electrical input power, energy, indoor air temperature and humidity, and indoor carbon dioxide (CO2) concentration were conducted. Two zero-cost strategies were studied and results were compared to baseline conditions. In general, the results show that all strategies can meet the indoor thermal environment and air quality requirements, except room temperature for Strategy 2 which ranges on average between 26.71 to 26.82C. In addition to the instant payback period (0 years), the results also indicate that as compared to baseline condition, Strategies 1 and 2 led to annual energy and cost savings of around 759.2 kWh (USD 64.40) and 1250.6 kWh (USD 106.08), respectively. In terms of environmental sustainability, Strategies 1 and 2 can avoid environmental CO2 emissions by 444.13 and 731.60 kg of CO2 per year, respectively. Due to these reasons and if the sensitivity of occupant comfort to room temperature during the break period can be tolerated, it is proposed that Strategy 2 is the best option for the AC system operation during the break period. Considering other buildings also adopted the same strategy, this small action can lead to a high impact, not only on energy and cost savings but also on environmental sustainability in the future.