Impact of condensate cooled air purging on indoor air quality in an air conditioned laboratory

Abstract

An air conditioned laboratory is assessed for improvement in IAQ with intermittent purging of pre-cooled fresh air. The base case refers to regular operation without admission of any external fresh air. Air quality studies for the base case, revealed that 58% of occupants reported unpleasant odor and 70% of occupants felt suffocation inside the laboratory. The modified case corresponds to the admission of pre-cooled fresh air at 28 ± 0.3 °C, achieved by passing through a Pre-Cooling Unit (PCU) which gainfully utilizes AC condensate discharged at 16–17 °C. PCU helps in reducing the outdoor air temperature by 3–3.5 °C through sensible and latent storage cooling systems. Experimental and simulation studies were carried out to analyze the effect of admission of pre-cooled fresh air into the laboratory. Results show that the CO2 concentration dropped to 42% in the vicinity of the first two rows. Further experimental and simulation studies conducted in a 44 m3 scaled-down room showed that the concentration of CO2 could be maintained below 1000 ppm with the supply of pre-cooled fresh air. The air quality studies carried out through a questionnaire survey to assess the occupant perception were in line with the experimental and simulation studies carried out for the full room and the scaled-down room.