Energy analysis of under-floor air distribution (UFAD) system: An office building case study

This paper presents the results of an experimental and theoretical investigation to evaluate an underfloor air distribution (UFAD) system existed in an office building working on hot climate. Air temperature a distribution and supply air velocity are measured in two measuring stations; each consists of eight temperature sensors which were installed to measure room air temperatures along zone height. The obtained data shows an inefficient operation of the UFAD system which deteriorates the advantages of energy saving that presumed by UFAD system. The building energy simulation program, EnergyPlus, was used to identify the best setting of UFAD system and compare it with the existed UFAD and the conventional ceiling based air distribution (CBAD) system. The simulation results show that setting of room thermostat at 26 C and supply air temperature at 18 C provides the best efficient UFAD system. Due to improper operation of the tested UFAD system, its actual consumption is found to be higher than the best simulated UFAD by 23-37% during July to October. Also, the simulation results show that the HVAC demand of UFAD is lower than CBAD by 37-39% during July-September and 51% in October. (C) 2013 Elsevier Ltd. All rights reserved.