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Building Efficiency and Indoor Air Quality - You Can Have Both
Abstract
Providing ventilation for acceptable indoor air
quality per ASHRAE Standard 62-1989 does not
require large increases in utility costs. Building
efficiency does not have to be sacrificed for a
healthy building. The ASHRAE 62- 1989
requirement for office ventilation is 20 cubic feet
of fresh air per occupant. However, the Standard
also allows various controls strategies to achieve
the same result. This paper will describe the
methods and application of several of these
options. However. due to length restrictions,
systems design criteria and comparisons will not
be addressed. The simplest and most commonly
used method is reducing the fresh airflow based
on building occupancy, or demand control
ventilation. This is currently done with carbon
dioxide sensors controlling inlet dampers or fan
control systems. As the people load varies
causing changes in carbon dioxide level, the
controls can vary the amount of ventilation air
entering the building. A second method is
removing the contaminants with added or special
filtration. This allows more air to be recirculated
but has specific limitations. Filters can remove
large particulates and some chemical
contaminants by changing the filter media.
However, a minimum amount of fresh air,
approximately 20% to 30%of the full 20cfm per
person. is still required to remove the carbon
dioxide and other contaminants not removed by
the filters.
Another group of methods is energy recovery
systems including; sensible heat wheels,
desiccant heat wheels, heat pipes, and run around
loops. These methods can be used on some
packaged equipment but is normally provided on
makeup air units and central air supply systems.
These built up units offer opportunities to
combine heat recovery, special filtration,
humidity control and demand control operations.
Citation
Kettler, G. J. (1998). Building Efficiency and Indoor Air Quality - You Can Have Both. Energy Systems Laboratory (http://esl.tamu.edu); Texas A&M University (http://www.tamu.edu). Available electronically from https : / /hdl .handle .net /1969 .1 /6755.