Thermal Transfer Systems TEMA Designations of Heat Exchangers - Manual

TEMA DESIGNATIONS OF HEAT EXCHANGERS
Because of the number of variations in mechanical designs for front and rear heads and shells,
and for commercial reasons, TEMA has designated a system of notations that correspond to
each major type of front head, shell style and rear head.
The first letter identifies the front head, the second letter identifies the shell type and the third
letter identifies the rear head type.
REMOVABLE BUNDLE EXCHANGERS
Removable bundle exchangers give the customer the ability to replace the tube bundle without
replacing the shell or bonnets. They are generally less cost effective than non removable
designs.
BEU/AEU- U Bundle Exchangers are generally the most cost effective design style of
removable bundle exchanger. Tubes may be water blasted, steam or chemically cleaned.
These units must have an even number of tube passes, sometimes limiting their applicability
to a service(e.g. they generally can not be used when a temperature cross occurs).
CEU- This design has the tubesheet welded to the bonnet. You can remove the bundle from
the shell, however to replace the bundle, the inlet bonnet is included or you must cut off the
tubesheet. Tubes may be chemically cleaned, water blasted or steam cleaned.
BEW/AEW- These are straight tube units with one floating head and one stationary head. The
floating head is generally sealed with an O-Ring. These units are most often used as oil coolers
or air coolers. Cleaning can be performed either by chemical, mechanical method, water blast
or steam cleaning.
AEP/BEP- These are straight tube units with one inside packed floating head and one
stationary head. The floating head is generally sealed with packing. These units are most often
used as intercoolers and aftercoolers with the gas on the tube side. They are also the most
common style for oxygen service exchangers. These units have been used in services with
tube side design pressures in excess of 2000 PSIG.
AES/AET- These units are the most expensive of the removable bundle designed units. The
floating head is internal to the shell. Tubes can be cleaned mechanically, chemically, water
blasted or steam cleaned. The design of these units forces an even number of tube side
passes therefore they suffer the same service restrictions as U bundles. Although in theory
one pass unit can be designed, this is rarely done. These units are generally used in services
where U bundles are not desired and the service may be too corrosive/damaging to the
packing used in AEP/BEP units.
NON REMOVABLE BUNDLE EXCHANGERS
These types of units are often used in high pressure services and services where you wish to
avoid leakage problems at gasketed joints. Another advantage is that they are generally more
cost effective than removable bundle designs.
NEU- The most cost effective design available. The tubesheet is welded to both the shell and
bonnet. There is no access to the shell. Tubes may be chemically cleaned, water blasted or
steam cleaned from inside only. These units are commonly used in high pressure services
(such as feedwater heaters), where process conditions allow for even pass exchangers.
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