Air Sealing Research Articles

Leakage Reductions for Large Building Air Sealing

This paper presents results from whole building air leakage tests used to document the leakage reduction due to envelope sealing and assess the accuracy of contractor’s estimates of the impact of their sealing. The measurements also compare the differences in envelope leakage reductions determined from depressurization versus pressurization tests and determine mechanical system leakage.The eight buildings were constructed between 1936 and 2007 with floor areas that ranged from 1100 to 22900 m2. The buildings were relatively tight with normalized air leakages that ranged from 2.66 to 7.41 m3/h·m2 at a 75 Pa pressure difference. Six of the buildings were air sealed with work that focused on spray foam sealing of accessible wall/roof joints and upgrades of exterior door weatherstripping. The sealing reduced air leakage from 6 to 17% with a median of 9%. The measured leakage area reduction was only 4% to 24% of the contractor bid estimates of leakage they would seal. Post-inspections indicate that the lower measured reductions were not due to incomplete air sealing, but an inability of the contractor to estimate the amount of leakage they would seal.There was consistently higher leakage under pressurization than depressurization. The ratio of pressurization to depressurization tightness for the pre and post sealing measurements varied from 1.12 to 1.31 with an average value of 1.21. The mechanical system leakage ranged from 0.57 to 3.78 m3/h·m2 and increased the envelope leakage by 17% to 103%. This suggests that mechanical system air leakage can have a significant effect on building air leakage when the systems are off.

제습로터의 공기누설모델 개발 및 성능 특성에 관한 실험적 연구

Key Words: Desiccant Rotor(제습로터), Air Sealing(누설방지모), Air Leakage(누설공기), Pressure Leakage(압력누설), Pressure Difference(차압)초록: 제습로터에서발생하는공기누설은로터와브러쉬형태의누설방지모틈새의양단사이차압에의해발생하는압력누설이지배적이며, 실험을통해압력누설특성을파악하였다. 그결과로, 압력누설량을로터와누설방지모의틈새면적과차압의함수로나타내었다. 위의상관식을바탕으로제습로터의공기누설모델을개발하였으며, 실험을통해측정된값과위모델을바탕으로계산된값을비교함으로써공기누설모델을검증하였다. 그리고풍량에따른제습로터의성능실험을수행하였으며, 공기누설모델을적용한성능분석을통하여실질적인제습량과공기누설량을확인하였다. 또한동일한제습로터가적용된제습냉방시스템을고려하여차압변화에따른공기누설의영향을공기누설모델을이용하여고찰하였다.Abstract: This study investigates the pressure leakage characteristics of a desiccant rotor with a brush-type airseal. Through a pressure leakage experiment, a correlation equation for the leakage air flow rate is obtainedas a function of the air seal area and pressure difference. Using this equation, an air leakage model for thedesiccant rotor is developed. By comparing simulation results with the experimental results for the desiccantrotor, the accuracy of the air leakage model is demonstrated. A performance test of a desiccant rotor withvarious air flow rates is carried out. Using the air leakage model, the effective mass flow rate and airleakage rate are found. In addition, the characteristics of the air leakage are analyzed for a desiccant coolingsystem using the developed air leakage model.