The effect of various forms of the tube cross on the energetic and exergetic analysis of helical tube in tube heat exchangers of an AHU with energy recovery unit in heating mode: injection of vapor/water particles

Over 40% of global energy usage is attributed to buildings. The power usage to meet the ventilation requirements accounts for more than half of the building energy damned. Energy recovery seems to be efficient to tackle high energy usage. The main purpose of this study was to examine the helical tube energy recovery unit (ERU) installation efficacy on the air handling unit (AHU) energy-saving potential in heating mode. Loading ERU, the fresh air sensible and latent energy content augmented which consequently reduced the secondary heater power load as well as the steam injection in the humidifier. Moreover, five climate regions were nominated to evaluate ERU incorporation effectiveness. Although in colder regions, the amount of saving energy was higher, but in warmer ones, the saving energy potential was higher. In the warmest region (Jeddah) and the coldest one (Edmonton), the saving energy was 171.1 and 235.77 kW, respectively. However, the power usage reduction for the former and the latter one was 41 and 18.4%. From the second law perspective, through evaluating the exergy loss, the AHU behavior was also examined and it was found that in the best-case scenario (Jeddah), the irreversibility was declined by 42.5% owing to using ERU.