Chapter hvac engineering Fundamentals: Part 1 Introduction

3.4.3
Elevation (above sea level)
Up to about 2000 ft the altitude related change in air density has less
than a 7 percent effect (see Table 3.3). With higher elevations, the
decreasing air density has an increasingly significant negative effect
on air-handling system performance. Heat exchanger (coil) capacities
are reduced. Fans still move the same volume of air, but the heating/
cooling capacity of the air is reduced because the air volume has less
mass. Evaporative condenser and cooling tower capacities are
slightly—but not entirely—proportionately reduced. The psychromet-
ric chart changes are described in Chap. 19. The air factor—sometimes
called the
air-transfer factor—
is also affected by elevation because it
Design Procedures: Part 1
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