Before embarking on designing or managing your electrical heat tracing project, it is important to consider the various options for monitoring and controlling your Electrical Heat Tracing systems. The use of monitoring of the circuit integrity is an advantage as it increases the overall system's reliability as failures in the heating and power distribution systems can be reported back to operations and maintenance personnel locally or at a central location.

Types and methods of control and monitoring need to be chosen based on various aspects:
- Process requirements
- Maintenance strategy
E.g., Do you prefer ease of maintenance/upkeep of the heat tracing solution or rather keep costs down?
- Power distribution parameters
- Economical considerations
E.g. What is the project budget?

Let’s explore the three core philosophies below when it comes to providing for your control and monitoring needs:

1) Local Controls

2) Local Controls with Central Monitoring

3) Central Controls and Monitoring

If your priority is based on the lowest installation cost, Local Control would be the most suitable.

1) Local Control

This employs locally mounted thermostats that are installed in the field and typically directly switch the heat tracing circuit. It offers the lowest installation cost but is limited in its applicability and makes a minimal contribution to lowering total operational costs (TOC). The cost and complexity of maintenance for this philosophy is high unless it is combined with the possibility of central monitoring.

There are mechanical and electronic options, depending on process requirements, each of which offers models for use in both hazardous and non-hazardous areas.

Mechanical thermostats are based on the bulb and capillary principle and are used for frost protection or temperature maintenance with a relatively narrow temperature band.

For mechanical thermostats, the advantages include easy installation and commissioning, low installation cost, and relatively accurate control. While disadvantages include: no temperature monitoring, imprecise setpoint setting, no maintenance information available, and limited temperature range.

Electronic thermostats measure temperature through an electronic circuit wired to a temperature sensor and are mainly used for temperature maintenance requiring a narrow temperature band. More sophisticated models offer additional features such as temperature display, high/low temperature alarms, or proportional ambient sensing control.

For electronic thermostats, advantages include easy installation and commissioning, low installation cost, accurate control, and sensor leads can be extended. While disadvantages include monitoring capabilities only in the field, no maintenance information centrally available, so maintenance can only be carried out reactively.

If your priority is for increased reliability, minimum cabling work and reduced total operation cost, the local control philosophy would suit your needs.

2) Local Controls with Central Monitoring

Advanced field-mounted controllers offer the option for direct switching locally in the field with the monitoring and configuration capabilities of a centralized control system. The controllers communicate via a bus system to a central location and can be configured and monitored in the field, via a hand-held device or remotely, via a touch-screen user interface and supervisory software.

This control and monitoring philosophy offers advantages for critical processes, small pipe networks and for high hold-temperature applications by minimizing cabling costs, reducing total operating cost and the project schedule by standardizing panel design.

Benefits of using such a system of local controls with central monitoring includes:

• Increased reliability, by permanent supervision of the integrity of the circuits.
• Cost savings, by reducing the power cabling, RTD wiring and simplified power distribution.
• Easier to install. By making direct heater connections you can reduce field junction boxes, lowering power cable cost, installation time and maintenance.
• Efficient process follow-up, by monitoring & alarming of temperatures, ground-fault currents, operating currents, and voltages.
• Increased personnel safety and simplified maintenance, by detailed problem reporting and accurate history logs.
• Simplified maintenance activities with handheld device, enabling monitoring of the electrical heat tracing system in the field without opening the control unit.

If your priority is for assured reliability and reduced total operating cost, the local controls with central monitoring philosophy would work for you.

3) Central Controls and Monitoring

Central control and monitoring systems are typically installed in panels where they provide control and monitoring for several heat tracing circuits or group of circuits at the same time. They offer advanced features like measuring ground-fault levels, operating currents and provide a wealth of other maintenance-related information.

A myriad of panel controllers are available with advanced control and monitoring capabilities specifically designed to meet the demands of industrial heat management systems. The controllers can be installed in any combination to deliver an optimized system for specific applications

Benefits of using such a system of central controls and monitoring includes:

• Increased reliability, by permanent supervision of the integrity of the circuits.
• Highest control flexibility via 1-phase or 3-phase controllers.
• Highest safety integrity level with the intelligent SIL 2 safety temperature limiter.
• Cost savings, by reduction of power cabling, RTD wiring and simplified power distribution.
• Efficient process follow-up, by monitoring & alarming of temperatures, ground-fault currents, operating currents, and voltages.
• Full heat tracing control via dedicated temperature, power, and current control algorithms.
• Increased personnel safety and simplified maintenance, by detailed problem reporting and accurate history logs.

Summary

After going through the article above, we hope you have gained a better understanding on some of the controls to consider when selecting your electrical heat tracing solution.

As an expert in the field of heat tracing with many years of experience and having completed various large-scale projects. Supermec provides both constant wattage and self-regulating trace heating systems. Get in touch with our friendly electrical heat tracing experts at sales@supermec.com or you can drop us a call at +65 68619522 to find out how we can assist you with your heat tracing needs and install a heat tracing system to help your business objectives today.