# Software, Control, Safety and Certification

# Dry Safe

# Is the dry safety contact according to SIL 1 or SIL 2?

It is not compliant with the IEC 61508 standard because the dry contact is not relevant for Enapter's risk analysis. There are current double protection, safety check valve at 42,5 bar, and more safety measurements. The panel is labelled "dry contact" instead of "safety" to avoid confusion.

# What happens in case of hydrogen leakages or a pressure drop?

Enapter's electrolysers have various sensors to ensure safe operation at all times. If a leak is detected or the pressure unexpectedly falls, the electrolyser will shut itself down and send an error message via the Enapter Management System (EMS). The maximum of hydrogen gas inside one electrolyser is around 20 NL. An internal ventilation system dilutes any possible leakages below the hydrogen lower explosive limits (LEL).

# What safety features are integrated?

Enapter's electrolyser is designed to be intrinsically safe. It performs leak test routines at regular intervals. Electrolysers from generation EL2.1 and on are CE certified, which allows straightforward integrations into existing safety concepts. In some cases, it might be necessary to install additional safety devices (e.g. hydrogen detectors on the top of the cabinet) to reach local regulations and safety concepts. These hydrogen detectors can be connected with the dry contact on the front panel. It is recommended to define two safety levels (e.g. at 10% and 25% of LEL):

  1. For 10% LEL: Trigger the dry contact for a safe shutdown

  2. For 25% LEL: Cut off the power directly

# Software Control

# How can the electrolyser and other devices be connected to the Wifi?

There are two possibilities: either connecting a device directly to the WiFi or connecting the Enapter Gateway and combining several devices at one place (including external devices like solar panels, fuel cells and storage tanks). For both options a smartphone with Bluetooth and WiFi as well as the Enapter app is needed. The app is necessary to set up the first connection.

# Which data can be monitored?

The Enapter Management System (EMS) allows tracking warning and error messages, inlet and outlet pressures, production volume and more. It can be accessed by any standard internet browser, such as Google Chrome and Firefox. Specific data sets can be downloaded in CSV format with a few clicks on the exports page.

When using Modbus, the same data can be read out via scripts and the same commands available in the EMS are also available via Modbus.

# Can I adapt the Enapter Management System (EMS) to an individual setup?

Yes. The EMS can be adapted to read and write data from all common communication standards of micro-grid systems and analogue inputs. If you would like to integrate a new system (inverters/power meters/fuel cells) into the EMS ecosystem, feel free to contact us for help!

# Is it possible to monitor the water inlet?

The water quality is not analyzed. Depending on the supplied water, suitable maintenance intervals can prevent a decreasing water quality and damage of the electrolyser.

However, a sensor at the electrolyser's inlet ensures that the pressure is between 1 bar and 4 bars. If it does not detect water presence, the electrolyser will stop hydrogen production and wait for a higher water input pressure whenever the internal tank arrives at low level. Warnings and water pressure can be monitored via the Enapter Management System.

# Is it possible to switch the system on and off and controlling the hydrogen pressure, flow regulation, etc. remotely?

Yes. The Energy Management System allows full monitoring and control via a website or mobile phone app. It also allows for efficient support and service.

# Is it possible to use a PLC to send commands to the equipment?

Yes. Enapter’s electrolysers are either monitored and controlled by the Enapter Management System EMS or via the Enapter gateway (a Linux based PC such as Intel NUC). Enapter can provide an interface to a PLC using Modbus TCP/IP and the Ethernet port.

# Is there a possibility to smart regulate the production?

Yes. Due to the rule based control, the system can be programmed to be as versatile as needed. In that way, weather and time depending control and other sensor driven actions can be realised by a simple CLI1 if-then-else logic. For an extended functionality and more complex situations, the scripting language Lua can be used. Generally, for rule based control, the Enapter Gateway is needed.

# What are the advantages of the Enapter mobile phone app?

Enapter's mobile phone application is an interface for system integrators and end-users who want to connect their devices such as electrolysers, dryers, communication modules and extensions. The Enapter mobile phone app allows an easy and secure system setup using QR codes to manage and monitor devices all over the world. It is available for Android and iOS.

# How can the electrolyser be switched off in case of an emergency? How long does it take to switch the electrolyser on again?

Yes, of course. The power can be cut off immediately by creating a safety chain using the Dry Con interface. Depending on the duration the electrolyser can be restarted again within a few minutes.

# Can the EL2.1 be managed without the Enapter mobile phone application or Cloud?

Yes. However, the most convenient and simple way to manage and monitor the electrolyser is via the Enapter Cloud or mobile phone app.

At the same time, the Modbus TCP interface can be used to provide all required data and functionality for integration with third party management software and Enapter provides full Modbus register table (here for the EL 2.1) together with samples of management scripts in python. The scripts are hosted on our github page and they help to understand the flows of monitoring, control and commissioning of the device.

# Are there updates available for the Enapter devices?

Yes. They can be automatically downloaded and installed via the mobile phone app or the cloud.

# Certification

# Is your system CE certified?

The EL2.1 is CE certified.

# Is the electrolyser ATEX2 certified?

Unfortunately, our system is not designed to be installed in an ATEX area. However, the product gases are only released from the designated interfaces (H2 outlet, O2 vent, and H2 purge). These have to be correctly managed during the on-site installation. It is the project developers/installers responsibility to ensure that the area where the electrolysers are installed must never contain any explosive atmospheres. An appropriate safety concept must be implemented to mitigate the risks of any failures and consequences of leakages of flammable gases. Such a safety concept could involve, for example, hydrogen sensors, forced ventilation, or natural ventilation.

# Is the piping system in accordance with a certification?

Yes. Enapter designs all hydrogen piping in accordance with ASME B31.12. All European guidelines refer to the ASME, which are very high standards for hydrogen piping and pipelines.

# Which countermeasures are necessary to prevent the creation of an ATEX area around the electrolyser?

The electrolyser has a standard ¼" Swagelok bite-type Stainless Steel connector for the hydrogen outlet piping. Internally it is protected by relief and check valves to prevent backflow of external tank/H2 distribution lines. In some few cases, local rules or regulations require welding.

However, it is usually sufficient to keep the oxygen outlet and the purge line separated and apart from ignition sources.

1: Command Line Interface

2: Atmospheres Explosibles