# Software and Control

# What are the safety interlocks build-in? e.g. in case of hydrogen leak? Or drop of pressure?

The Electrolyzer has various sensors to ensure safe operation at all times. If a leak is detected or the pressure unexpectedly falls, the Electrolyzer will shut itself down and send alarm or error messages via the Enapter monitoring system.

# What safety features are integrated?

The Electrolyzer is designed to be intrinsically safe. It self-pressurizes the hydrogen side and performs leak test routines at regular intervals or when some data suggests a leak could be present. The EL2.1 is CE certified, and in our experience, it is very straightforward for our customers to integrate the Electrolyzer into the safety concept on their sites. Depending on the specific site safety concept and local regulations, some of our customers install additional safety devices such as a hydrogen sensor in order to cut the power if any hydrogen leaks occur on the site. The Electrolyzer also has a dry contact on the front panel that triggers a safe shutdown based on an external signal.

# Are Dryers connected to the EMS system? Can the Dryer be controlled via Modbus?

The Dryer communicates via the EMS adapter, it does not have its own interface. Once the entire system has been configured with the EMS adapter, the Electrolyzer can be controlled via the Modbus interface. The Dryer works automatically when the outlet pressure of the electrolysis increases.

# Has the water inlet some sort of monitoring?

The water treatment has no monitoring installed - depending on the use of the system, suitable maintenance intervals should be defined to prevent the filters from becoming dirty and the water quality from falling. We are planning to integrate a conductivity / TDS1 sensor into the EMS adapter via UCM. If you were able to install such a sensor in your water pipe to the Electrolyzer, the risk of damage due to poor water quality would be significantly reduced.

The Electrolyzers have an internal hydrogen leakage detection, so they will shut themselves down in case of a substantial leak being detected. However, there is no gas sensor present in each machine. If required by the safety concept on the end user site, we recommend a sensor to be installed at the top of the cabinet. We recommend defining two safety levels (for example at 10% and 25% of LEL2):

  1. When a small unexpected leak occurs, a dry contact on the front panel of the EL2.1 triggers a safe shutdown.

  2. In critical situations with large leakages, simply cut off the power.

# Are the modules equipped with an internal ventilation system? Is the internal ventilation enough to dilute any hydrogen leakage and to reduce its concentration below LEL[^2]? In case the internal ventilation stops, also hydrogen production is automatically discontinued?

Yes, the Electrolyzers have an internal ventilation system that dilutes any leakage (only in case of damage, normally the Electrolyzer has zero external leakages) below hydrogen LEL. In case the internal ventilation stops, the hydrogen production also stops.

# In case of an emergency/failure, how much hydrogen can get out of the cabinet? Potential hydrogen leakages will be diluted thanks to the ventilation in any case, or there is any possibility for pure hydrogen to get out of the cabinet?

Each Electrolyzer contains a maximum of around 18 NL of hydrogen gas. If it escapes due to a sudden internal leakage of the hydrogen piping, it would be diluted by the ventilation system.

# Do I have to use the Enapter EMS monitoring system or can the system also be controlled via the Ethernet port via Modbus?

While we believe our EMS is the best way to access, monitor and control the Electrolyzers, but you don’t have to use it. To control the Electrolyzer our customers can use the Ethernet port with Modbus TCP to integrate it with their system of choice.

# Is it possible to remotely control the system in terms of on/off switching, hydrogen pressure, flow regulation, etc?

Absolutely, the best way to control our Electrolyzers is via our Enapter energy management system, which allows full monitoring and control via a web dashboard and mobile app. It also collects monitoring data to enable efficient support and service of the system.

# What does the monitoring measure and control when it comes to the Dryer?

As for our software monitoring system, it measures and displays input pressure, output pressure, several temperature levels, fan speeds, digital in- and outputs. You can control (start/stop/reboot/OTA3 firmware update). This is for the Dryer only, for the Electrolyzer there is obviously much more specs to monitor and control. Please contact us for a demo of the monitoring software.

# What kind of control system is used in the Electrolyzer? We require PLC control. If it is PLC control, which brand of PLC will be suitable for the equipment?

Our Electrolyzers are monitored and controlled by the Enapter EMS. It is a software-based system, where all the data from the Enapter Electrolyzers is collected by a local “gateway”, which is a Linux based PC, such as Intel NUC. We can provide a suitable interface to connect the Gateway to your PLC, such as Modbus or Ethernet. It is also possible to control each individual Electrolyzer via a Modbus communication interface.

# What kind of smart production regulation possibilities are there using the EMS in my system?

The EMS and its system of extension modules can perform a large variety of smart features. Due to the rule based control, the system can truly be programmed to be as versatile as needed.

For example the system can regulate production rates to keep the output pressure stable at a certain pressure set point (useful for constant flow rate requirements). Another example is the use case for the Big Thing micro-grid, using the EMS and the integrated extension modules, the system can regulate which devices are running when, anticipate bad weather and determine how much hydrogen is needed to be stored for continuous autonomy.

# Apart from the system components used in the Big Thing, can we use the EMS extensions to integrate inverters/power meters/fuel cells from other suppliers?

Short answer: Yes! The adaptability of the EMS allows it to communicate and read data from every standard of communication normally used in micro-grid systems, as well as analogue inputs. If you would like to integrate a new system into the EMS ecosystem, please contact us for help!

# What does the Enapter mobile app enables me to do?

Enapter's Mobile application is an interface to system integrators and end-users’ connected devices such as Electrolyzer, Dryer, Communication Module and Extensions. The Enapter mobile app allows easy and secure system setup using QR codes, management and monitoring all over the world. Mobile applications are available for Android and iOS.

# Which operating systems are supported by Enapter EMS system?

The mobile app is available for Android and iOS. The web dashboard runs in any standard Internet browser, such as Google Chrome, Firefox, etc.

# Where I can download the Application?

You can download it in the Apple app store or Google Play app store.

# How can I setup custom control logic for my energy system?

The Enapter Gateway enables this functionality. One Gateway can be installed per user site to enable advanced control features and mitigate Internet connectivity issues. Using the Gateway, the Enapter Engine can be configured in a simple if-then-else logic defined by the user. This logic allows to send action commands to devices based on conditions driven by sensors or other device’s data integrated in the energy system. The logic is set using the convenient CLI4 and can extend to any level of branching and complexity. In cases when standard condition rules are not sufficient it is possible to extend functionality by contributing additional logic using "Lua" scripting language.

# How can I export data for analysis?

The Enapter Cloud collects performance and error data from the Enapter Gateway and all connected devices such as Electrolyzers, Dryers and UCM. It stores it in a time series database and provides real-time or on-demand visualization of collected data on customizable dashboards. Specific data sets can also be downloaded in CSV format with a few clicks on Exports page.

# In the event of an emergency, can the system be switched off by cutting off the electrical power in order to stop hydrogen production immediately? Once the emergency has been cleared, how long does it take to switch the Electrolyzer on again?

Yes, of course. If you have for example an external hydrogen sensor, you could trigger a relay and cut of the power to the system. Once the emergency is cleared, the Electrolyzer could be restarted with the normal procedure, the time depends on the ambient conditions but if the temperature is >20 °C should be no more than 4-5 minutes to reach maximum production rate (otherwise, a heating period will first be initialized to heat up the system up to the minimum temperature).

The EL2.1 has a dry contact on the front panel, which can be used to create a safety-chain. If the contact is closed, the Electrolyzer will immediately initiate an emergency shutdown.

1: Total Dissolved Solids

2: Low Explosive Limit

3: Over the air

4: Command line interface