There is no question that VAV systems are an economical means of providing multiple zones of control from a single air handling unit, but there is increasing opposition to these systems by multi-users such as the armed services and large building management companies.
Many of the problems and complaints stem from improperly sized VAV terminals furnished with pressure independent (P.I.) controls. This practice is a " black eye" on our industry, an industry that almost universally assumes that the pressure independent feature will atone for oversized terminals, poor duct design, and sloppy supply duct pressure controls. This same industry would frown on installing a 6" modulating steam valve in a 6" line yet it condones installing a 6" VAV terminal in a 6" branch duct.
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6.1 Introduction The primary purposes of an air-conditioning system are to supply adequate ventilation air to, and to control the dry-bulb temperature in, each of the zones served by the system. A...
The UCM-420A is one of the most versatile products sold by Kele . Although this product is capable of performing many control functions, it was primarily designed as a Setpoint Controller. Since the...
12.5 TEMPERATURE CONTROL AND ZONING Please refer to Chapter 6, "Controls, Operation, and Maintenance," for a more detailed discussion of control issues. There are several approaches to address zones...
4.8 Duct Sizing Duct-sizing considerations for cold-air distribution systems are essentially the same as those for conventional designs. The reduction in supply air volume offers the designer more...
OVERVIEW This chapter was contributed by Allan Daly. A commonly cited benefit of UFAD systems is that they save energy when compared to "standard" overhead (OH) air distribution systems. At...
