Investigation on pre-cooling potential of UFAD via model-based predictive control

This study investigated the operation cost-saving potential of an underfloor air distribution (UFAD) system by applying model-based predictive control (MPC). Based on the measurements from an actual building, the grey-box building model was constructed using a decentralized approach. The simulation case study was then carried out to quantify the saving potential of the MPC compared to feedback control. For the cooling season, the saving percentage of the MPC exceeded 30%, while those of the intermediate season were reduced by approximately 20%. More savings were achieved when the outdoor air temperature and solar radiation were high. The size of the plenum was not sensitive to the saving rate. The large savings were attributed to precooling that utilizes the cheaper utility cost of the off-peak and higher efficiency of the HVAC plant. This suggests that the larger thermal mass of the under plenum, including the air and still structure (bracket), is suitable for maximizing pre-cooling of the system. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

This study explores the potential for cost-saving in operating an underfloor air distribution (UFAD) system using model-based predictive control (MPC). By constructing a grey-box building model based on real building measurements, the study quantifies the energy-saving potential of MPC compared to feedback control through simulation. The results show that MPC can achieve energy savings of over 30% in the cooling season and around 20% in the intermediate season. Higher savings are observed when the outdoor air temperature and solar radiation are high. The size of the plenum does not significantly affect the energy savings, as the major savings are achieved through precooling using off-peak electricity and more efficient HVAC equipment.