CEMP-E
TI 810-32
10 January 2002
2-4. SYSTEM SELECTION. The system type selected will be based on the type of media that is
distributed.
a. High Temperature Water and Steam/condensate Systems. The order of preference for system
types for high temperature and high pressure systems are:
(1) Aboveground Heat Distribution System. This is the least expensive system and historically
requires the lowest maintenance and operating costs. However, the safety and aesthetics of an
aboveground system are not always desirable and must be accepted by the end user.
(2) Heat Distribution Systems in Concrete Trenches. This is the most dependable of the buried
distribution systems. The piping is totally accessible through removable concrete covers, the piping does
not come in contact with the soil, and ground water is drained away from the piping system to low point
drains. Except in rare instances, this is the system that should be selected if aboveground is not
acceptable with the end user.
(3) Pre-engineered Underground Heat Distribution System. This type of buried distribution
system should be selected as the last option due to very short system lives which are typically caused by
poor drainage, poor corrosion protection, and improper installation. Instances where it would be used would
be when aboveground is not acceptable with the end user or when drainage swales and high ground water
prevent the installation of a concrete trench system.
b. Low Temperature and Chilled Water Systems. The order of preference for system types for hot
water, chilled water or combination hot/chilled water are:
(1) Aboveground Heat Distribution System. This is the least expensive system and historically
requires the lowest maintenance and operating costs. However, the aesthetics of an aboveground system
are not always desirable and must be accepted by the end user. In addition, aboveground systems are
typically not used for chilled water because of potential freezing problems in colder climates and heat gain in
warmer areas.
(2) Prefabricated Underground Heating/Cooling Distribution System. This buried distribution
system is relatively inexpensive and dependable. The non-metallic casing materials provide excellent
protection from corrosion and the lower temperatures and pressures allow the system to operate for
extended periods of time. It is an excellent application for chilled water since the system is installed
underground, limiting the amount of heat gain to the system.
2-2
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