Page 248 - HVAC Pump Handbook

Rishel_09.qxd 20/4/06 6:34 PM Page 245

Source: HVAC Pump Handbook

Chapter
9

Configuring an HVAC

Water System

9.1 Introduction
This chapter continues the evaluation of water use and configuration
of HVAC water systems. The economical and proper application of
HVAC pumps depends totally on proper system design. An under-
standing of these principles of good water system configuration
should result in the economical selection of pumps and in efficient
pump operation. The continuing theme of this book is the intelligent
application of HVAC pumps to eliminate the mechanical devices used
in the past, to overcome the overpressure of these water systems that
was caused by improperly sized and misapplied pumps.
Reviewing the basic equation for pumping energy,

Q H 0.746
Pump kW
3960 P E

Q H
(6.14)
5308 P E

the energy required by a pump rises with increase in system flow or
head and with decrease in pump efficiency and motor or motor and
variable-speed drive efficiency. It is therefore incumbent on the HVAC
designer to develop a water system with a minimum of flow and head
for a particular duty. This chapter addresses the piping for these
water systems in an attempt to secure the optimal design that recog-
nizes the preceding equation. This chapter embraces hot and chilled

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