Field Investigation: The Disruptive Application of Spiral Tube Heat Exchangers in the Long-Duration Energy Storage Market

“Spiral tube heat exchangers are a mature technology. In the field of long-duration energy storage, their application can be described as truly disruptive.”

“In fact, the total cost of spiral tube heat exchangers is lower than that of conventional heat exchangers.”

“Concerned about molten salt freezing and blockage? Built-in electric heat tracing inside spiral tube heat exchangers can completely solve this problem.”

On the afternoon of April 21, ESPLAZA Long-Duration Energy Storage Network members visited Wuhan East Petrochemical Heavy Equipment Co., Ltd. (hereinafter referred to as “Wuhan EPHE”), a leading manufacturer of spiral tube heat exchangers, as part of a field research tour.

Addressing several key concerns of high interest to the long-duration energy storage industry, WuhanEast responded with the above opening statements.

The company's President Lu Wei, Vice President Ma Zhengmao, Deputy Chief Engineer Zhou Chuan, and Production Director Yan Jincheng, along with other senior executives, received the research delegation.

This research activity was co-organized by ESPLAZA Long-Duration Energy Storage Network along with its sister platforms CSPPLAZA Concentrating Solar Power Platform and IESPLAZA Integrated Energy Services Network. Co-sponsors included Wuhan East Petrochemical Heavy Equipment Co., Ltd., Haiwei Technology (Group) Co., Ltd., and Yangzhong Xianglong Electrical Appliances Co., Ltd.

A New Choice in Heat Exchange: Six Core Advantages

A coiled-tube heat exchanger primarily consists of a shell and a tube bundle. The tube bundle is composed of heat transfer tubes, tube sheets, a central mandrel, spacer bars, and clamps.

Based on the characteristics of the tube sheets, three structural configurations are available: single-stream integral tube sheet, multi-stream zone-divided tube sheet, and multi-stream split tube sheet.

Deputy Chief Engineer Zhou Chuan noted that Wuhan East has collaborated with the Institute of Process Engineering, Chinese Academy of Sciences, to develop spiral tube heat exchangers since 2012. After more than a decade of R&D and practical application, the company now possesses full-range manufacturing capabilities for spiral tube heat exchangers.

Leveraging the unique helical-flexible tube bundle structure, spiral tube heat exchangers demonstrate comprehensive performance that outclasses conventional heat exchangers under the demanding conditions of high-pressure, high-temperature, rapid start-stop cycles, and large-scale operation typical of long-duration physical energy storage:

1. Compact Structure, High Space Utilization: Heat transfer area of up to 170–200 m² per cubic meter — far exceeding conventional heat exchangers — making it especially suited for energy storage projects with limited footprint;

2. Multi-Fluid Heat Exchange: Up to 10 fluids can participate in heat exchange simultaneously, meeting the multi-energy coupling demands of “heat-power-cooling” within energy storage systems;

3. Strong Thermal Compensation Capability: Low stress levels and high fatigue resistance; minimal risk of leakage at the welds between heat transfer tubes and tube sheets;

4. Easy to Scale Up: The current maximum heat transfer area per single unit has reached 30,000 m², enabling a single device to meet the heat exchange requirements of 300 MW-class compressed air energy storage systems, significantly reducing the number of equipment units and system complexity;

5. High Heat Transfer Intensity and Coefficient: The helical tubes induce secondary flow on the tube side, while staggered spacer bars and tubes create turbulence on the shell side, enhancing heat transfer;

6. Reduced Shell-Side Pressure Drop: No significant transverse resistance loss in the fluid flow direction, reducing fan/pump energy consumption and lowering system operating costs.

A Disruptive Application in the Electric Power Storage Sector

President Lu Wei stated that spiral tube heat exchangers are not a new technology — they have been reliably applied in traditional petrochemical refining and other fields for many years.

Wuhan East developed China's first titanium alloy coiled-tube heat exchanger for an offshore platform, used for seawater preheating of natural gas. It occupied only one-third of the footprint of the original design and reduced costs by 50%.

In collaboration with the Dalian Institute of Chemical Physics, CAS, Wuhan East developed the first coal-to-ethanol coiled-tube feed heat exchanger, capturing over 90% of the domestic market share.

The coiled-tube heat exchanger designed for Sinopec Zhanjiang's 1.8-million-ton reforming unit revamp project replaced the original plate-type heat exchangers, resolved the leakage problem caused by pressure and temperature fluctuations, and has been operating stably for 7 years.

In addition, Wuhan EPHE's spiral tube heat exchangers have also delivered impressive results in multiple polysilicon tail gas recovery projects and LNG cold energy utilization projects.

Zhou Chuan noted that some operating conditions in traditional petrochemical applications are more stringent than those in power storage. Applying spiral tube heat exchangers to power storage is truly a disruptive application — there is absolutely no technical challenge. In its early days, the technology was import-dependent and expensive, but as domestic technology has matured, current manufacturing costs are now roughly on par with traditional shell-and-tube heat exchangers, while advantages in land use, energy consumption, and total lifecycle cost are even more pronounced.

Total Cost Lower Than Conventional Heat Exchangers

Many believe that the biggest drawbacks of spiral tube heat exchangers are complex manufacturing and high cost, leading to limited market acceptance.

In fact, this view is one-sided.

The valid part: spiral tube heat exchangers require heat transfer tubes to be precisely wound in a helical pattern around a central mandrel, with adjacent layers wound in opposite directions and uniform inter-tube spacing maintained throughout. This process demands specialized equipment and skilled manual labor, requires extremely high process precision, has a long manufacturing cycle, and the unit cost of each individual heat exchanger is indeed higher.

The invalid part: when comparing only the purchase price of a single unit, spiral tube heat exchangers do cost more than conventional shell-and-tube exchangers. However, because of their high heat transfer efficiency and large per-unit capacity, the number of units required for a project can be significantly reduced, effectively lowering land occupation. Combined with superior resistance to vibration, fouling, fatigue, and fluctuating loads, as well as long-cycle operational capability, the total lifecycle cost is actually lower.

Zhou Chuan explained, taking compressed air energy storage (CAES) projects as an example: the heat transfer efficiency of spiral tube heat exchangers approaches that of plate-type exchangers, while simultaneously offering high-pressure capacity, high-temperature resistance, fatigue resistance, and long-cycle operation capability. They are particularly well-suited for critical nodes such as multi-stage compression cooling and regenerative heat exchange in compressed air energy storage.

According to data provided by Wuhan EPHE, in the 3rd and 4th compression stages of compressed air energy storage, spiral tube heat exchangers improve efficiency by 30–50% compared to cross-flow types.

Under concentrating solar power (CSP) molten salt storage conditions of 28 MPa and 560°C, a conventional U-tube heat exchanger weighs approximately 350 tonnes per unit, whereas the coiled-tube version weighs only 110 tonnes, with significant improvements in process compatibility and cost optimization.

According to Wuhan EPHE's test data, in a 100 MW CSP project, the coiled-tube solution can reduce investment by 30–50% compared to traditional solutions, lowering the cost of heat exchange equipment from RMB 20 million to RMB 14–15 million per project.

Its multi-stream technology can combine two separate units into a single integrated device, supporting dynamic adjustment under partial load conditions, further reducing costs and improving efficiency.

Some industry insiders have expressed concern that the complex internal piping of spiral tube heat exchangers makes it very difficult to address molten salt freezing and blockage issues. In response, Zhou Chuan stated: “Wuhan EPHE has completely resolved this issue by integrating electric heat tracing inside the spiral tube heat exchangers.”

Market Acceptance Has Increased Significantly

The power storage market represents a major emerging opportunity for spiral tube heat exchangers.

Vice President Ma Zhengmao, drawing on his extensive marketing experience, noted that market acceptance of spiral tube heat exchangers in the power storage sector has grown significantly compared to a year ago. An increasing number of CSP/energy storage project developers and design institutes have developed deeper understanding and more scientifically grounded evaluations of the technology.

The real, signed project orders that WuhanEast has secured are the best proof. In recent years, the company has successively won multiple project orders in the emerging long-duration energy storage market, all of which are currently in execution.

Ma Zhengmao stated that the barrier to market adoption of spiral tube heat exchangers lies not in the technology or the product itself, but in the industry's entrenched perceptions and decision-making inertia. Traditional power design institutes using conventional heat exchanger solutions represents a 100% “safe” and orthodox choice that carries no risk of error. Moreover, most investors in long-duration energy storage projects are state-owned power enterprises, which tend to be inherently more cautious when it comes to procurement decisions involving new technologies and products.

But traditional perceptions and mindsets will ultimately be broken. Advanced technologies and products will eventually achieve large-scale commercial adoption.

Ma Zhengmao said: “We need to first execute the projects we have already signed to the highest standard, making them benchmark demonstration applications. On that foundation, we are confident that the market for spiral tube heat exchangers will open up at an accelerated pace.”

President Lu Wei stated that Wuhan EPHE is extremely bullish on the long-duration energy storage market. The company is currently building a new production base at Changjiang Jinkou Wharf. The new facility will feature 60,000 m² of workshop space, lifting capacity upgraded to 600 tonnes, maximum processing diameter expanded to 8 meters, and the ability to leverage Yangtze River waterway transport to overcome logistics constraints and support the delivery of super-large equipment.

“We expect the new production base to begin operations in the second half of this year. By then, Wuhan EPHE will possess significantly enhanced manufacturing and delivery capabilities, enabling us to better serve the long-duration energy storage market,” Lu Wei stated with conviction.

Note: This research activity is positioned as a public-interest industry event. Neither the company being visited nor the participating delegates are required to pay any fees. ESPLAZA will continue to visit member companies in other provinces and regions across China in the coming period. To apply for your organization to be featured as a research host, or to join future research tours, please contact ESPLAZA Guo Shilong: 13716608372 (WeChat same).

This research activity is dedicated to building a practical offline communication platform to help participants effectively link resources and achieve greater business cooperation. By providing free in-depth media coverage of the visited company, it helps enterprises with market promotion and brand building. It also serves the development of the integrated energy services industry, and the resulting research findings will be submitted to relevant supervisory authorities and industry experts.

About Wuhan EPHE: Wuhan East Petrochemical Heavy Equipment Co., Ltd., founded in 2007, has developed R&D and manufacturing capabilities centered on spiral tube heat exchangers, large-scale shell-and-tube heat exchangers, and large-scale tubular reactors, covering a variety of pressure vessel product series in multiple materials. The company independently developed process calculation software for spiral tube heat exchangers and is the drafting organization of the coiled-tube heat exchanger industry standard NB/T 10938-2022. Its designed and manufactured spiral tube heat exchangers have reached industry-leading parameters: maximum design pressure 28 MPa, maximum design temperature 730°C, maximum equipment diameter 5 m, maximum length 28 m, maximum heat transfer area 30,000 m², and maximum equipment weight 500 tonnes.