Dehumidification and Cooling Loads From Ventilation Air

Abstract

Summary Examination of typical behavior of weather shows that latent loadsusually exceed sensible loads in ventilation air by at least 3:1 andoften as much as 8:1. A designer can use the engineering shorthandindexes presented in Table 1. to quickly assess the importance of thisfact for a given system design. To size those components after theyare selected, the designer can refer to Chapter 24 of the 1997 Hand-book of Fundamentals, which, for the first time, includes separatevalues for peak moisture and peak temperature. Acknowledgments The authors would like to thank the Gas Research Institute forthe financial support necessary for the BIN program development,and the U.S. Department of Energy and the National Renewable En-ergy Laboratory in Golden, CO for generating and making availablethe TMY-2 data set, without which these indexes could not have beencalculated. Also, we thank James Judge, PE of LINRIC Company foruse of the psychrometric routines contained in the BIN program, andfor his assistance in assuring their accurate and appropriate use. Ad-ditionally, the members of ASHRAE TC’s 4.2 and 3.5 have providedgenerous and extensive assistance over the last 8 years in assessingthe effect of weather moisture on systems, and supporting and guid-ing the 8-year effort to calculate and include correct values for peakmoisture loads into nonproprietary industry reference books. Finally,our thanks to Prof. Donald Colliver of the University of Kentuckyfor his completion of research project RP-890, which provided thenew data for Chapter 24 of the 1997 Handbook of Fundamentals.About the AuthorsLewis G. Harriman III is director of research at Mason-Grant,Portsmouth, NH. He is the chair of the Handbook Subcommitteeof ASHRAE TC 3.5 (Desiccant and Sorption Technologies) andis the author of The Dehumidification Handbook.Dean Plager is Senior Analyst at Quantitative Decision Sup-port, Portsmouth, NH. He is also adjunct Professor of Quantita-tive Analysis at the Whittemore School of Business Administra-tion at the University of New Hampshire.Douglas Kosar is Principal Product Development Manager atthe Gas Research Institute, Chicago, IL. His primary responsi-bility is development of gas-driven air treatment technologiesfor commercial buildings.