Using internal fan balancing system to avoid excessive pressurization on high rise buildings in hot and humid climates

Infiltration through the building envelope impacts several aspects of building performance. To avoid infiltration-induced issues in hot and humid climates, building pressure is typically maintained at a slightly positive level compared to outdoor pressure in warm weather. However, due to the stack effect, high-rise buildings actually have a different pressurization level requirement at each floor, and a conventional pressurization system is unable to maintain these different pressurization levels. Field pressurization measurements performed on an eight-floor building on the Texas A&M University campus in College Station, TX indicate that, when the indoor-outdoor temperature difference is about 11.1 °C, the ground level of the building can have an average 8 Pa pressurization level while simultaneously having an average 1 Pa on the top floor. This results in extra energy consumption due to over-pressurization of the lower floors. An internal fan balancing system is proposed to eliminate or reduce this excess consumption. eQUEST simulation results indicate that 5.8%-7.0% annual savings on the utility bill can be achieved by installing the Internal Fan Balancing System in the same eight-floor building where the pressurization level measurements were performed.