From ASHRAE GreenGuide: The Design, Construction, and Operation of Sustainable Buildings, Second Edition


Considerable improvements in the seasonal efficiency of conventional heating plant equipment, such as boilers and furnaces, were made over the last several decades. Designers should verify claims of equipment manufacturers by reviewing documented data of this equipment demonstrating the efficiency ratings.

Some unconventional equipment and techniques to achieve greater efficiency or other possible green building design goals are described in the GreenTips at the end of this chapter.


Chilled-water plants are most often used in large facilities. Their benefits include higher efficiency and reduced maintenance costs in comparison to decentralized plants.

Generally, a chilled-water plant consists of:

  • Chillers

  • Chilled-water pumps

  • Condenser-water pumps (for water-cooled systems)

  • Cooling towers (for water-cooled systems) or air-cooled condensers

  • Associated piping, connections, and valves

Because chilled-water temperature can be closely controlled, chilled-water plants have an advantage over direct-expansion systems because they allow air temperatures to be closely controlled also.

Often chilled-water plant equipment will be in a single central location, allowing system control, maintenance, and problem diagnostics to be performed efficiently. Chilled-water plants also allow redundancy to be easily designed into the system by adding one (or more) extra chillers, chilled-water pumps, condenser-water pumps, and cooling tower fans.

Chiller Types

Electric chillers used within chiller plants employ either a scroll-, reciprocating-, screw-, or centrifugal-type compressor (in order of increasing size). Models can be offered with both air-cooled or water-cooled condensers, with the exception that centrifugal compressors today are water-cooled only. Absorption chillers, powered by steam, hot water, natural...

Products & Services
Chillers (industrial)
Industrial chillers cool water using refrigeration cycles to provide a constant stream of coolant for manufacturing and laboratory processes.
HVAC Chillers
Heating, ventilation and air conditioning (HVAC) chillers are refrigeration systems that provide cooling for industrial and commercial applications. They use water, oils or other fluids as refrigerants.
Chilled Beams
Chilled Beams are a type of convection HVAC system that are used to heat or cool rooms. Pipes of hot or cold water are passed through the beam. As the beam heats or cools it radiates the warmth or coolness to the surrounding air.
Condensers are devices which accept a vapor stream and convert it to a liquid using heat transfer and/or compression.They are used in steam turbines for power plants, in cooling units for in-process fluids, and in air conditioning systems for buildings and automobiles.
Cooling Towers
Cooling towers are defined as any open water recirculation device that uses fans or natural draft to draw or force air to contact and cool water by evaporation.

Topics of Interest

RENEWABLE/NONRENEWABLE ENERGY SOURCES There are often discussions about using renewable energy sources as a way to power the world, but little is done to actually implement it. This chapter focuses...

By Gary Shamshoian, P.E., Genentech, Inc., and Don Nurisso, P.E., EYP Mission Critical It is also critical to determine the degree of redundancy required to ensure reliability. Any additional costs...

4.2 Cooling Plant Cold-air distribution systems commonly use ice storage systems or nonstorage plants as the source of cooling. These systems distribute chilled water or a secondary coolant to remote...

7.1 TYPES OF CONDENSERS USED IN INDUSTRIAL REFRIGERATION The three main types of condensers used in general refrigeration systems are: air-cooled water-cooled evaporative All of these serve the...

At the time this article was written, Stephen P. Kavanaugh was an associate professor of mechanical engineering at the University of Alabama, Tuscaloosa. Reprinted from ASHRAE Transactions 1992, Vol.

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