Design Guide for Hazloc / Industrial
Self regulating trace heating systems
01-5800-7N0012/-
05/2019-EHT-432712
Notice
Technical data subject to change without notice.
No claims for damage arising from alternations, errors or misprints shall be allowed.
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Selection of the required components for power connection, control and monitoring, end termination etc.
A typical heating circuit with self-regulating trace heaters consists of:
▪
Power supply / cold lead cable connection
▪
Trace heater splices / junctions (optional)
▪
Control and monitoring units (optional)
▪
End termination
Step 11: Determine the required trace heater power connection kit:
→ Example
▪
From Step 10: 1 Heating circuit with 1 power connection kit =
PBS
-
200
-
E
Step 12: Determine if control equipment is required:
BARTEC provides a variety of control products, from simple mechanical thermostats to sophisticated digital controllers and control and monitor-
ing systems designed specifically for use with our trace heating products. This section will help you select and specify the right control products
for your application.
General design considerations for temperature control:
When designing your trace heating system, you should consider the following factors.
▪
Adding control elements increases the installation and maintenance costs of the heating system, but allows tighter temperature control, energy
savings and more efficient use of plant maintenance personnel’s time.
▪
The thermal environment of a trace heating system varies greatly, especially at valves, pipe supports, and other heat sinks. It is therefore
seldom possible to achieve very tight temperature control.
▪
The temperature of a heat tracing system is based on ambient temperature and can vary by as much as 20 °C when the system is uncon-
trolled. You can choose between 2 approaches for temperature control:
Ambient sensing control
Ambient sensing control:
▪
uses an on-off thermostat that senses ambient tem-
perature
▪
is more energy efficient than self-regulating control
because the heating circuit is energized only when the
temperature drops below the set-point
▪
is most suitable for freeze-protection applications
where multiple circuits can be controlled by a single
sensing point
▪
flow path considerations (flowing or non-flowing) are
not required with ambient control.
Line sensing control
Line sensing control:
▪
regulates the desired maintain temperature by turning
the heating circuit on if the pipe temperature falls be-
low the set-point and turning it off if it exceeds the set-
point
▪
the most energy-efficient method for controlling heat
tracing is a line-sensing thermostat, because a flowing
pipe will typically not need any additional heat to keep
it at the proper temperature
▪
needs a separate circuit controlled by a line-sensing
thermostat for each flow path
▪
where a piping system has tees and therefore multiple
flow paths, more than one thermostat may be re-
quired.
NOTICE
Line sensing provides tighter temperature control than ambient sensing but flow paths may require additional controllers.
Line temperature sensor
Ambient temperature sensor
Line temperature sensor
