Page 212 - HVAC Pump Handbook

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Source: HVAC Pump Handbook

Chapter
8

The Use of Water

in HVAC Systems

8.1 Efficiency of Operation
The use of water in HVAC systems has been much like the ordinary
use of water in our civilization. Water has been plentiful and cheap, so
why not use it? Such has been the situation in HVAC water systems.
Now the cost of energy to move water through these systems is no
longer less than a penny per kilowatthour, and water itself should be
conserved. Conservation must be practiced, and we have the tools to
achieve the efficient use of pumping energy in HVAC water systems.
The development of digital electronics has opened the door to the
achievement of higher efficiency in the movement of water through
these systems. This added efficiency is most pronounced in hot water,
chilled water, and condenser water systems in the HVAC field. The
elimination of energy-consuming mechanical devices, the use of variable-
speed pumps, and the wiser control of water temperatures to increase
the efficiency of boilers and chillers have all brought conservation of
energy in the HVAC field.
The major users of water and pumping energy in the HVAC field
are chilled, condenser, hot, and boiler feed water. This chapter reviews
the design considerations that are common to all these systems. Later
chapters will be devoted to the specific design requirements for each
of the water systems. Energy consumption is a major concern for all
these systems.
For hot water systems, the development of the condensing-type
boiler has brought a much higher level of boiler efficiency, over 90 per-
cent compared with the traditional 80 percent for noncondensing boil-
ers. This means also that hot water systems need not be designed with

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