Experimental study of an underground pipe gallery pre-cooled chimney ventilation system for a computer room

Natural ventilation is crucial for reducing the energy consumption and carbon emissions of buildings. However, it is often impossible to meet indoor thermal requirements in hot climates. In this study, an integrated natural ventilation system with an underground pipe gallery for pre-cooling and a built-in chimney to enhance the thermal pressure was proposed to cool a computer room. A full-scale experimental platform was constructed to confirm the feasibility of the system. The system performance was investigated by comparing two experimental scenarios, thermal pressure-driven natural ventilation and fan-assisted ventilation, during the transition season in a hot outdoor environment. The underground pipe gallery pre-cooled chimney ventilation system effectively provided a suitable indoor environment for the occupied area, with a mean temperature of 29.1 °C and relative humidity of 57.6 %. The proportion of hours in which the hourly average temperature around the server rack meets the Class C level for computer rooms specified in the national standard is 66.7 %. The maximum pre-cooling capacity of the underground pipe gallery was 3.5 kW. When the assisted fan was operated, the environmental stability of the equipment area further improved, and the system had the potential to operate continuously for 24h to provide a suitable indoor environment.This study provides a strategic solution to passive building design by demonstrating the viability of using an underground pipe gallery for pre-cooling in natural ventilation systems.