Double Helical Coil Thermal Fluid Heaters
When an industrial heating system goes down mid-production, every hour offline results in lost output and rising costs. For facilities that run around the clock, the priority is not just thermal efficiency but also long-term reliability under continuous heat load. Double helical coil (DHC) thermal fluid heaters are engineered specifically to address each.
Industrial heating systems play a critical role in maintaining production efficiency, product quality, and operational reliability. When facilities require high-temperature heating with dependable performance, double helical coil thermal fluid heaters offer a proven solution. Designed for demanding industrial processes, these systems deliver efficient heat transfer, long service life, and reliable operation in continuous-duty environments.
What Is a Double Helical Coil Thermal Fluid Heater?
A double-helical-coil thermal fluid heater uses two nested, helically wound coils to transfer heat from combustion gases to circulating thermal fluid. The inner coil is located in the center of the heater, where it absorbs radiant heat and is exposed to the highest temperatures, while the outer coil adds additional heat by absorbing heat by convection in the flue-gas path.
By adding a second helical coil, the heater increases the amount of tube surface area exposed to the hot gas stream. This added surface area allows more heat to be recovered before the gases exit the heater, which will improve thermal efficiency compared with a similar single-coil design, depending on the overall heater configuration and operating conditions.
Key Benefits of Double Helical Coil Heaters
High Thermal Efficiency
Double helical coil thermal fluid heaters typically achieve thermal efficiencies of 83% to 88%. To put that in practical terms: on a 10 MMBtu/hr heater running 24/7, the difference between 75% and 85% efficiency can represent $40,000 to $80,000 in annual fuel savings depending on local fuel costs. Over a 15 to 20 year service life, that gap compounds significantly.
Supports High Operating Temperatures
Many industrial processes require elevated temperatures to maintain production standards. Double helical coil heaters are designed to support operating temperatures exceeding 550°F, providing the flexibility needed for a wide range of manufacturing and processing environments.
Ideal for Large Process Heating Demands
The DHC Series is engineered for facilities with significant heating requirements. Its robust design allows it to handle larger process loads while maintaining reliable and efficient operation.
Low Fluid Pressure Drop
A key advantage of thermal fluid heating systems is minimizing resistance within the circulation loop. Double helical coil heaters are designed to maintain relatively low fluid pressure drop, helping reduce pumping requirements and improve overall system efficiency.
Long Service Life
With proper operation and maintenance, double helical coil thermal fluid heaters can provide an expected service life of 15 to 20 years, making them a long-term investment for industrial facilities.
Performance at a Glance
| Performance Factor | Double Helical Coil Heater |
| Thermal Efficiency | 83–88% |
| Operating Temperature | Exceeds 550°F |
| Fluid Pressure Drop | Minimal |
| Expected Service Life | 15–20 Years |
| Best-Fit Application | Large-scale process heating |
| Operating Schedule | 24/7 Continuous Operation |
Double Helical Coil (DHC) vs. Serpentine Coil with Economizer (AHE): Which Is Right for Your Facility?
Enerquip offers both the DHC Series double helical coil heater and the AHE Series serpentine coil heater. Both are built for demanding industrial process heating, but they are optimized around different strengths.
The AHE Series serpentine coil delivers 86 to 88% thermal efficiency with an economizer included as
standard. Its multi-pass tube design provides a greater heat transfer surface area of a single helical coil, with heat reaching around the full tube circumference for more uniform distribution. This reduces hot spots, extends thermal fluid life, and supports a service life of 25 or more years. It is the higher-capacity option, ranging from 2.1 to 45 MM BTU/hr, and handles both continuous and batch processing well.
The DHC Series double helical coil achieves 83 to 88% efficiency in a compact vertical footprint with smooth, continuous spiral flow and minimal fluid pressure drop. It is well-suited for continuous 24/7 operation within a 2.1 to 16 MM BTU/hr range, and carries a lower upfront cost.
| AHE Series | DHC Series | |
| Thermal Efficiency | 86 to 88% | 83 to 88% |
| Capacity | 2.1 to 45 MM BTU/hr | 2.1 to 16 MM BTU/hr |
| Service Life | 25+ years | 15 to 20 years |
| Economizer | Standard | Not included |
| Footprint | Larger | Compact |
| Price Point | $$$ | $$ |
Not sure which fits your process? Our engineers can evaluate your load profile, operating schedule, and temperature requirements to point you in the right direction.
Applications for Double Helical Coil Thermal Fluid Heaters
Double helical coil heaters are well-suited for industries that require reliable, around-the-clock heating, including:
- Chemical processing
- Asphalt production
- Petrochemical facilities
- Food processing
- Manufacturing operations
- Industrial drying systems
- Continuous production environments
Because of their vertical-standard design and ability to operate efficiently at high temperatures and under continuous load conditions, this system design is frequently selected when operating efficiency, footprint, and long-term reliability are primary considerations.
Why Efficiency Matters in Process Heating
Energy consumption is often one of the highest operating costs in industrial facilities. A heater running at 85% efficiency versus 75% does not just save fuel, it reduces emissions, lowers wear on auxiliary systems like pumps and burners, and improves process temperature consistency. Over a 15 to 20 year service life, the cumulative impact on operating costs is substantial.
Double helical coil thermal fluid heaters offer a balanced combination of efficiency, durability, and high-temperature performance, making them a dependable solution for demanding industrial applications.
Effective Heating Solutions from Enerquip
Double helical coil thermal fluid heaters provide an effective heating solution for facilities that require high operating temperatures, continuous operation, and dependable performance. With thermal efficiencies ranging from 83% to 88%, minimal fluid pressure drops, and an expected service life of 15 to 20 years, these systems continue to be a preferred choice for large-scale industrial process heating.
Talk to an Enerquip engineer about your facility’s heating load, operating schedule, and temperature requirements. We will help you determine whether a DHC heater or an alternative configuration is the right fit for your operation.
More from the Enerquip Blog
https://www.enerquip.com/solutions/industrial-heaters/serpentine-coil-technology/
https://www.enerquip.com/solutions/industrial-heaters/helical-coil-heaters/
https://www.enerquip.com/solutions/industrial-heaters/low-nox-heaters/
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