Many heating companies face a practical challenge when upgrading heat exchange stations for intelligence: a large amount of equipment at the site is still within its service life. Fully replacing all equipment would not only be costly but also wasteful. Therefore, the focus in the industry is on how to maximize the use of existing equipment while achieving "smart brains" through partial upgrades and system integration. In this article, Henan Rentai explores how to achieve smart heat exchange stations without a full replacement of equipment.
Intelligent Upgrade Approach Based on Existing Equipment
Introducing a PLC Control System as the Core
The core of intelligent transformation for old heat exchange stations is to equip them with a reliable central controller—PLC (Programmable Logic Controller). PLC control cabinets are stable and adaptable to harsh heating environments, ideal for long, uninterrupted heating seasons. By adding PLCs and Human-Machine Interfaces (HMI) to the station, manual control can be replaced with automated monitoring and control.
The PLC can manage:
Primary and secondary network supply/return temperature adjustments.
Start/stop and speed control of circulation and makeup pumps.
Valve openings at the heat exchanger inlets and outlets.
With a PLC in place, network parameters are maintained within set ranges with minimal human intervention. Communication modules within the PLC can also transmit real-time data to heating company backends for remote monitoring and dispatching.
Adding Sensors and Instruments for Data Visualization
Intelligent operation starts with data acquisition. Without overhauling pipelines, sensors can be installed at key points to gather real-time operational data:
Temperature and pressure transmitters on primary and secondary network inlets and outlets.
Flow meters on the secondary network return pipes.
Level gauges or pressure sensors on water tanks.
Outdoor temperature sensors for environmental data.
These sensors form the "sensory organs" of the heat exchange station, feeding data to the PLC or remote instruments. Henan Rentai’s systems, for example, monitor water temperatures in real time using high-precision sensors to maintain settings.
Upgrading legacy instruments is also essential, such as replacing analog pressure gauges with digital transmitters with 4-20mA outputs or mechanical thermostats with digital sensors. These upgrades significantly enhance data accuracy and depth without altering the main pipeline.
Upgrading Actuators for Controllable Adjustments
Intelligence also requires control capability. Evaluating and upgrading actuators ensures automated regulation:
Replace manual valves on the secondary network with electric actuators controlled by the PLC.
Retrofit fixed-speed pumps with frequency converters for variable-speed control, optimizing energy use.
Add intelligent electric control valves on the primary network to precisely regulate flow.
These upgrades empower the system to adjust in real time to demand changes without major equipment replacement. Henan Rentai’s solutions emphasize optimizing energy efficiency through intelligent pump control and variable frequency drives.
Communication Networking and Platform Integration
To enable multi-station coordination under centralized management, each heat exchange station’s PLC cabinet should include communication interfaces (Ethernet, RS485/Modbus) or IoT gateways for transmitting data to supervisory systems.
This can be achieved through:
Dedicated heating networks or fiber optics.
4G industrial routers with data encryption for cloud platform integration.
These communications solutions allow old stations to be included in modern smart heating networks without altering core infrastructure. Henan Rentai’s control systems support RS485, Ethernet, and GPRS modules, ensuring flexibility in connecting to various monitoring centers for remote management.
Challenges and Countermeasures for Retaining Old Equipment
Challenge: Compatibility Between Old and New Interfaces/Logic
Older devices might not be compatible with modern PLC systems due to mismatched signals, limited actuator control capabilities, or incompatible communication protocols.
Countermeasure: Modular Design and Interface Adaptation
Use signal converters (e.g., voltage to 4-20mA converters, Modbus to PROFIBUS gateways).
Apply relay intermediation to isolate new PLCs from old high-power contactors.
Thoroughly map old control logic and replicate or optimize it within the PLC program.
These measures ensure smooth communication and coordination between new and legacy systems, avoiding unnecessary hardware overhauls.
Challenge: Performance Limits and Reliability of Old Equipment
Legacy pumps may be inefficient, valves slow to respond, and aged components prone to failure.
Countermeasure: Targeted Upgrades and Redundancy
Retain old pumps but add bypasses, soft starters, or frequency drives to extend lifespan.
Install redundant sensors for critical data points.
Replace aged components like breakers and terminals in control cabinets.
Programming PLCs to alternate equipment operation (e.g., rotating pumps) can distribute wear evenly, enhancing system reliability. The principle is "retain if viable, replace if necessary," ensuring cost-effective yet robust upgrades.
Henan Rentai’s Expertise and Service Advantage
Henan Rentai Electrical has extensive project experience and technical reserves to offer customized intelligent upgrade solutions for old heat exchange stations. Their engineering teams conduct comprehensive site assessments and adopt modular integration strategies to ensure compatibility between new systems and old equipment.
Rentai’s control systems support multi-brand PLCs and various communication protocols, ensuring flexibility in adapting to existing technologies. Their deep expertise in heating control algorithms, such as climate compensation and constant pressure control, boosts post-upgrade energy efficiency and heating quality.
Henan Rentai provides a full suite of services:
Solution design.
Equipment provisioning.
On-site installation and commissioning.
Operator training.
24/7 technical support.
With these advantages, Rentai has helped many heating enterprises achieve intelligent upgrades of old heat exchange stations under the principle of minimal investment and maximum output. This facilitates the industry’s shift toward smart, efficient, and green heating.
For more information, please contact Henan Rentai Electric:
Phone: 17638563962 / 0371-56520104
Email: info@hnrentai.com