Recently, HuaDe Hydrogen Energy Technology successfully completed the development of its CARNEU-5 pure-hydrogen fuel cell combined heat and power (CHP) system. The system is scheduled to be delivered shortly to an integrated project in Northwest China, which combines photovoltaics, water electrolysis for hydrogen production, hydrogen refueling, power generation, and heat supply. A photograph of the actual product is shown in Figure 1.

The CARNEU-5 system is a hydrogen fuel cell-based combined heat and power (CHP) unit. Through an electrochemical reaction, the device converts hydrogen and air into direct current (DC) electricity; this DC power is then inverted into alternating current (AC) via a power electronics system and fed into the electrical grid for user consumption. The waste heat generated during operation is recovered and supplied to users in the form of hot water. The entire system has a power generation capacity of 5,000 W and operates via a 380 V three-phase AC grid connection. It is capable of supplying hot water at temperatures ranging from 50°C to 60°C, with a thermal output exceeding 4,500 W. The system boasts a rated net power generation efficiency of over 47% across its entire operational cycle, with a peak net efficiency exceeding 53%. Featuring a classic exterior design, the system occupies nearly half the volume of the H2ES series—a product line that incorporates an onboard hydrogen reformer. Detailed system specifications are presented in Table 1.

The CARNEU-5 pure hydrogen fuel cell combined heat and power (CHP) system adheres to the GB/T 27748 series of standards and incorporates the following technologies in its design:

**Dedicated Low-Voltage Power Generation Stack**
The CARNEU-5 system utilizes a low-voltage, low-temperature Proton Exchange Membrane (PEM) fuel cell stack independently developed by HuaDe Hydrogen Energy. Unlike automotive fuel cell stacks, this stack employs an enhanced proton exchange membrane and membrane electrode assemblies (MEAs) with optimized catalyst loading. This design effectively mitigates the degradation rate of the membrane and the loss rate of the catalyst, thereby significantly extending the stack's service life and meeting the longevity requirements for long-duration power generation operations. Furthermore, the catalyst within the MEAs features a CO-poisoning-resistant design, enabling it to withstand prolonged exposure to CO concentrations ranging from 0 to 10 ppm without degradation. This ensures voltage stability and enhances the system's operational redundancy during power generation. Additionally, this specific stack model is capable of operating in a mixed-gas mode—for instance, utilizing a mixture of 75% hydrogen and 25% carbon dioxide.

Figure 2: Fuel Cell Stack CO Tolerance Test Curve

Micro-flow Hydrogen Circulation Process

Figure 3: Power Generation and Efficiency Curves

High-Security Design

The CARNEU-5 system employs safety PLC control and features a design incorporating multiple, comprehensive safety chains. It integrates numerous hydrogen and smoke detectors—positioned both within the fuel cell interior and throughout its external environment—and incorporates a suite of safety response functions within its programming. In the event of abnormal internal operating conditions—such as over-temperature, over-pressure, or under-pressure—or external anomalies—such as leaks or fires—the system issues a pre-warning; furthermore, it will automatically initiate a shutdown when necessary to ensure safe system operation. Additionally, the stack system utilizes a low-pressure design, with an operating pressure of merely 8–14 kPa. By significantly reducing the pressure within both the piping and the stack itself, this design vastly enhances the safety of the stack and minimizes the risk of hydrogen leakage to the greatest possible extent.

**Cold Start Design**

The CARNEU-5 system features a dedicated cold start unit, enabling rapid startup at temperatures as low as -20°C. This significantly enhances the product's adaptability for use in cold climates, such as those found in northern regions.

**Modular Design**

Adopting a modular design philosophy, the CARNEU-5 system comprises four primary modules: the fuel cell module, control module, power electronics module, and thermal management module. This modular architecture facilitates easy parallel operation of multiple units. The entire system is designed to be compact, streamlined, and easy to maintain. Installation is straightforward, requiring no specialized environmental conditions, and the system supports "plug-and-play" functionality. Furthermore, the enclosure features a sealed design that maintains a slight negative pressure within the cabinet; this allows for safe and stable installation in enclosed environments, such as basements.

**Convenient Operation**

The CARNEU-5 system incorporates an intelligent control design that enables one-touch startup and shutdown, ensuring an exceptionally convenient and user-friendly operating experience that requires no specialized technical expertise. Touchscreen operation is illustrated in Figure 4, while the device's main operating interface is shown in Figure 5. Various system parameters during operation are displayed on the smart screen, allowing users to monitor real-time data—such as temperature curves, pressure curves, and individual fuel cell voltages—at any time. Operating parameters are displayed in Figure 6; the temperature interface is shown in Figure 7; the pressure curve in Figure 8; and individual cell voltages in Figure 9. Additionally, the system supports a programmable power adjustment mode, allowing users to tailor the fuel cell system's power output to meet their specific requirements. The system will then operate continuously on a 24-hour cycle, adhering to the specific parameter curves set by the user; these time-segmented operating parameters are illustrated in Figure 10.

Figure 4: Touchscreen Operation

Figure 5: Device Main Operation Interface

Figure 7: Temperature Profile Interface

Figure 8: Pressure Curve

Figure 9: Stack Single-Cell Voltage Interface

Figure 10: Time-Segmented Operation Parameter Setting Interface

Historically, the company has focused on residential-scale fuel cell combined heat and power (CHP) systems featuring integrated natural gas reforming modules. Fully cognizant of the challenges associated with sourcing hydrogen in distributed energy environments, the company has provided users with integrated solutions for on-site hydrogen generation and utilization (the H2ES product series). The pure-hydrogen product delivered on this occasion marks the company's inaugural step in its strategic transition from "grey hydrogen" to "green hydrogen." The successful development of the first pure-hydrogen fuel cell CHP system—the CARNEU-5—has further solidified the company's independent command over core technologies, including the integration of modular, low-power fuel cell CHP systems; high-performance, low-pressure fuel cell stacks for power generation; and distributed energy management systems.
Moving forward, the company will continue to pursue a dual-track strategy—advancing both grey and green hydrogen solutions in parallel—to flexibly and conveniently provide customers with hydrogen energy storage, power generation, and CHP system solutions characterized by high adaptability to diverse application scenarios.