Daniel A. Katzenberger
Harvard Extension/January Term
ENVR – E-200
January 17, 2016
Homework Assignment #4 Rev 0
Draft of the Introduction
Optimizing Indoor Air Quality for Human Health, Cognitive
Performance, Building Life Cycle Costs, and Long Term Environmental
Sustainability
Summary
For more than a century mechanical ventilation systems in buildings have
generally been designed to provide only enough outside air to minimize
human complaints and discomfort. This was done primarily to save on
energy costs associated with bringing outside air into buildings. However,
recent studies have found a significant relationship between increases in
outside air supplied to buildings and improved human cognitive
performance. One finding from these studies suggests that cognitive
performance may be doubled by increasing the amount of outside air
brought into a building. However, increasing outside air in buildings will
affect building energy performance and costs, which will in turn affect the
environmental impact of the buildings over its lifetime. Further information
is needed to determine the optimum and feasible outside air flow rates in
buildings before ventilation standards and practices can be improved to
improve human health and cognitive performance.
The purpose of this study it to determine the feasibility of increasing outside
air in buildings in order to improve human health and cognitive
performance. Once feasibility is established, this study will attempt to
correlate increases in outside air to life-cycle costs and lifetime
environmental impacts of buildings, with the goal of determining if there are
optimum quantities of outside air that can be delivered to buildings to
improve human health and cognitive performance while also optimizing
lifecycle costs and and minimizing overall lifetime environmental impacts.
This study intends to achieve these goals by studying existing buildings,
specifically by 1) analyzing pre-construction outside air ventilation
calculations for the buildings, 2) field measuring the performance of the
ventilation systems in these buildings, and then 3) modeling predicted future
energy use and costs in these buildings given changes in the outside air flow
rates delivered to the buildings.
The first part of this analysis will look for relationships between the outside
air ventilation calculations at two different phases of the design of a green
Daniel A. Katzenberger
Harvard Extension/January Term
ENVR – E-200
January 17, 2016
Homework Assignment #4 Rev 0
Draft of the Introduction
(e.g., LEED Certified) building. The baseline data will include the calculated
outside air flow rates prior to being submitted for LEED certification review.
The comparative data will include the same variable; however, the
comparative outside air flow rates will be analyzed after the ventilation
calculations have been submitted for LEED certification review. It is
hypothesized that the LEED certification review process might lead to
increases in outside air flow rates in buildings, even when pre and postcertification calculations are based on the same reference standard. This
relationship is important to understand because proposed changes to
ventilation standards and practices may result in unpredictable outcomes if a
relationship between outside air calculations and actual building
performance cannot be determined.
The second part of this analysis will look for relationships between the postcertification review calculations from the first part of this study and field
measurements of outside air flow rates in the same buildings, as they are
currently being operated. It is hypothesized that the amount of outside air
being delivered to buildings may be different from the amount of outside air
determined in the pre-construction ventilation rate calculations, and it is
important to understand this relationship before ventilation standards and
practices may be successfully modified to result in predictable outcomes.
The third and final part of this analysis will combine information from the
first two parts of this analysis, as well as the known mechanical equipment
that is included in each building, and model and compare energy use of each
building given different quantities of outside air. This final part of the
analysis hopes to answer several questions; the most significant question to
be answered is: Is there an optimum feasible ventilation rate or calculation
process that can be determined based on the results of this study?
It is hoped that the results of this study will inform current ventilation
standards, building codes, and green building rating systems so that
buildings can be designed and operated to optimize outside air flow rates to
improve human health and cognitive performance while also minimizing
lifecycle energy costs and lifetime environmental impacts.