Page 208 - HVAC Pump Handbook

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Pump Drivers and Variable-Speed Drives

Pump Drivers and Variable-Speed Drives 205

7.5 Engine-Driven Pumps

Engine-driven pumps are not common today in the HVAC field. They
are used for emergency backup in event of power failure on critical
installations or for peak shaving where high demand charges occur
during a specific period of the day. Their value is contingent on the rela-
tive costs of electric power, fuel oil, and natural gas. Natural gas–driven
engines may become more common as the peak cooling loads increase
on electric power distribution systems. They can be an economic alter-
native to ice or chilled water storage on some installations.
Engines for this purpose normally operate on natural gas, while
some may operate on no. 2 fuel oil. All parts of the fuel storage or deliv-
ery installation must meet the requirements of an approving agency
such as Underwriters Laboratories or the attending insuring agency.
Noise abatement may be a problem with the use of these engines.
Also, the exhaust effluent of these engines must meet local environ-
mental codes, particularly oil-fired engines with the higher carbon
percentage in the fuel.

7.6 Summary
The selection of motors and drives for HVAC pumps is critical for the
realization of a cost-effective and efficient installation. It is obvious
that there are a number of calculations and decisions that must be
made by the designer to actualize such a pumping installation. Care
should be taken in the selection of electric motors, ensuring that the
best type, rating, and enclosure have been selected for each application.
Too often the motor is just specified as a three-phase induction motor.

7.7 Bibliography
AC Motor Selection and Application Guide, Bulletin GET-6812B, General Electric
Company, Fort Wayne Ind., 1993.
Energy Policy Act of 1993 as It Relates to Motors, Bulletin GEK-100919, General
Electric Company, Fort Wayne, Ind., 1993.
Keith H. Sucker, PE, Private Communication, Halmar Robicon Group, Pittsburgh, Pa.,
1994.
Richard H. Osman, Medium Voltage Drives for Induction and Synchronous Motors,
2001.
Private Communication, Halmar Robicon Group, Pittsburgh, Pa., 1990.

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