Energy-Saving Potential of Extending Temperature Set-Points in a VRF Air-Conditioned Building

Abstract

Building energy savings and occupant thermal comfort are the main issues in building technology. As such, the development of energy-efficient heating, ventilation, and air-conditioning (HVAC) systems and the control strategies of HVAC systems are emerging as important topics in the HVAC industry. Variable refrigerant flow (VRF) systems have efficient energy performance, so the use of VRF systems in buildings is increasing. However, most studies on VRF systems focus on improving mechanical efficiency, with few studies on energy-efficient control while satisfying the thermal comfort of occupants. The goal is to estimate the energy-saving potential of adjusting the temperature set-points and dead-band (range) in VRF air-conditioned building. To do so, we analyzed the influence of control strategies of a VRF system on human thermal comfort and energy consumption using a simulation method. The results showed that energy consumption can be reduced by 25.4% for predicted mean vote (PMV)-based control and 27.0% for the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) comfort range control compared with the typical set-point temperature control of a VRF system. The indoor thermal environments of the analyzed control strategies are controlled in the thermal comfort range, which is based on a PMV at ±0.5. Compared with the typical set-point control, PMV and ASHRAE comfort range-based control reduced the operation time of the compressor in the VRF system.

Living with air-conditioning: experiences in Dubai, Chongqing and London

“…Dynamic temperatures settings for AC that move in line with outdoor temperatures could offer at least a minimal level of acclimatisation. Previous work on changing setpoints has tended to focus on energy efficiency (Xu et al 2020b) or optimising both efficiency and occupant thermal comfort (Kim et al 2020). The findings here additionally note the need for acclimatisation to hotter weather (rather than cold indoor settings) and this is an additional benefit.…”

Determination of Thermal Comfort Zones through Comparative Analysis between Different Characterization Methods of Thermally Dissatisfied People

“…Hwang et al [25] highlighted the relevance of the integration between APD and TCZ when they discovered that only 40% of hospital environments they analyzed were within the comfort zones recommended by ASHRAE [13]. This research gap was demonstrated by Park and Nagy [26] and Kim et al [27], where the authors emphasize the importance of exploring and understanding both the thermal sensation and the comfort zones to maximize energy savings. In view of the relevance of this subject, this work aims to determine thermal comfort zones through a comparative analysis between different methods used by thermally dissatisfied people.…”

Comparison of Multi-Control Strategies for the Control of Indoor Air Temperature and CO2 with OpenModelica Modeling

“…A poor IAQ or uncomfortable indoor environment could cause health problems and diseases, as well as Energies 2020, 13, 4425 2 of 20 negatively affect work productivity and occupants' performance [5,6]. However, there is always a trade-off between energy consumptions and maintenance of IAQ and TC [7]. Energy-efficient HVAC systems might compromise IAQ and TC, while strict construction of healthy and comfortable indoor environment usually demands more energy consumptions.…”