Measurement of Infiltration Rate of Warm Air into Walk-in Coolers

The tracer gas technique is used to experimentally measure the infiltration of warm air into walk-in coolers during its nominal operating conditions. The tracer gas samples captured before, during, and after the infiltration process are collected through sampling probes inside and outside the cooler. The infiltration rate can be calculated from this data. The transient nature of the infiltration rate that is captured in this approach signifies the shortcoming of the existing methodologies currently practiced in industry. It is found that the infiltration rate is a function of the temperature gradient between the inside and outside air, relative humidity, and the void volume in the cooler. It is also demonstrated that it is possible to derive a closed form equation based on the experimental data that can replace the current equations