Performance of Whole-building Pressurization as Countermeasureagainst Stack Effect in High-rise Office Building

This paper deals with pressurization usingHVAC systems on each floor as acountermeasure against stack effect generated inthe winter in high-rise office buildings that donot use revolving doors at the entrance. Awhole-building pressurization system isinstalled in a 23-story building located in Tokyoin order to prevent various problems caused bythe stack effect, e.g. noise generation at elevatordoors or large heating loads and deterioration ofthe thermal environment at a 2-story entrancehall due to the increase of outdoor airinfiltration through automatic entrance doors.Pressurization is realized not by increasingsupply air volumes but by reducing exhaust airvolumes on each floor.Measurements were made on 4 days in thewinter to evaluate the performance of thepressurization system. Outside conditions suchas outside temperatures, wind speeds anddirections, and the indoor thermal environmentsuch as air temperature distributions, airvelocity distributions, globe temperatures andPMV's at the entrance hall (on the 1st basementand 1st floors) were measured using dataacquisition systems. Pressure differencesbetween the indoor and the outdoor weremeasured on the I st basement, 1 st, 7th and 17thfloors. Pressurized air volumes were set at 2cases of 500 or 2000 m"(h. floor).According to the measurement results, negativepressures generated at the entrance hall weredecreased by 10 Pa or more by increasingpressurized air volume from 500 to 2000 m3/(h*floor). At the same time, indoor velocitiesshowed a sharp drop and indoor airtemperatures were kept high with the higherpressurized air volumes. These resultsdemonstrate that the whole-buildingpressurization systems are effective ascountermeasures against problems caused bythe stack effect in high-rise office buildingswhile conserving energy by reducing heatingloads at the entrance halls and also reducingelectric energy consumed for exhaust fans oneach floor.