Trane TRG-TRC014-EN VAV Building Characteristics, Variable Thermal Load Profiles, period one

period one

What Is Variable Air Volume?

notes

VAV Building Characteristics

▲Variable thermal load profiles

▲Multiple, independently-controlled spaces

▲Common return air path

Figure 15

There are some basic building characteristics that favor the application of VAV systems. We will discuss three:

nVariable thermal load profiles in the spaces.

nThe need for multiple, independently-controlled spaces.

nThe existence of a common return air path.

Variable Thermal Load Profiles

percent space load

100east-facing space

75

50

25

west-facing space

0

6	12	6
a.m.	noon	p.m.

Figure 16

A key feature of a VAV system is its ability to realize both fan and refrigeration energy savings at part-load conditions. A building with construction and utilization characteristics that cause the thermal load profiles of the spaces to vary throughout the day and year is an excellent application for a VAV system.

The fact that the west-facing space in this example has a very different load profile than the east-facing space allows the VAV system to take advantage of this energy savings at all hours of the day.

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