Energy Impacts of Infiltration and Ventilation in U.S. Office Buildings Using Multizone Airflow Simulation

Published: June 01, 1999

Author(s)

Andrew K. Persily, Steven J. Emmerich

Abstract

With exception of a few analyses of the impacts of ANSI/ASHRAE Standard 62-1989 and energy use in specific buildings, the energy used in commercial buildings due to infiltration and ventilation flows has received little attention. However, as improvements have been made in insulation, windows, etc., the relative importance of these airflows has increased. The energy impacts of infiltration and ventilation flows in U.S. office buildings was estimated based on the analysis of a set of 25 buildings developed to represent the U.S. office building stock. The energy calculation was performed by a bin method with infiltration flows determined by multizone airflow model simulations. The results show that infiltration is responsible for about 13% of the heating load and 3% of the coding load for U.S. office buildings. In newer buildings, infiltration is responsible for 25% of the heating load and 4% of the cooling load due to the higher levels of insulation. The total annual energy impact of infiltration in U.S. office buildings is 60 PJ of heating energy (15%) of the total heating energy) and and 6 PJ of cooling energy (4% of the total cooling energy). It is also estimated that heating and cooling energy use due to ventilation is 17 PJ at a rate of 2.5 L/s (5 cfm) per person and 138 PJ at 10 L/ss (20 cfm) per person. The results also show the potential energy savings due to tightening building envelopes and better control of ventilation system airflows. This calculation of the national energy impacts of infiltration and ventilation in office building is a rough estimate, with its accuracy limited by the calculation method and imput data. This paper presents an intermediate step of this analysis, and an improved estimate will be calculated with a combined multizone airflow and building energy simulation model..It is also estimated that energy use due to ventilation is 17 PJ at a rate of 2.5 L/s (5cfm) per person and 138 PJ at 10 L/s (20 cfm) per person. The results also show the potential energy savings due to tightening building envelopes and better control of ventilation system airflows.
Conference Dates: October 24-27, 1998
Conference Title: IAQ Conference
Pub Type: Conferences

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Keywords

building technology, computer simulation, energy, mechanical ventilation, modeling, office buildings, ventilation
Created June 01, 1999, Updated February 19, 2017