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

HEAT GENERATORS (HEATING PLANTS)

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.

COOLING GENERATORS (CHILLED-WATER PLANTS)

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...

Copyright American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. 2006 under license agreement with Books24x7

Products & Services
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.
Chillers (industrial)
Industrial chillers cool water using refrigeration cycles to provide a constant stream of coolant for manufacturing and laboratory processes.
Condensers
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

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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.

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...

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