February's freezing temperatures were the perfect opportunity to test how the entire system would behave in a real-world environment with temperatures approaching 20 degrees below zero.
In early February, forecasts called for hard freezes. What was a major setback for most of the country was a great opportunity for us to test the operation of our H2BASE hydrogen generator in a nice old-fashioned way, without climate chambers and laboratories.
Although the individual parts of our H2BASE hydrogen generator have already been extensively tested in extreme temperatures from -20 to 50 °C and the operation of the system is thus guaranteed at these temperatures, the February frost was the ideal opportunity to test how the entire system would behave in a real environment at temperatures approaching 20 degrees below zero. In fact, one of the model applications for the generator is to power winter outdoor events such as Christmas markets.
Frost can cause problems for the system in several places. Probably the most sensitive area of the system is the hydrogen fuel cell, which is at risk of not only malfunctioning but also being damaged by freezing. This is because the cell works like electrolysis in reverse, so while electrolysis breaks down water into hydrogen and oxygen while consuming electricity, the fuel cell combines hydrogen and oxygen to create electricity. It is here that water is formed, which, due to its properties, can damage the cell when it freezes.
In order to prevent the hydrogen cell in the H2BASE system from freezing, the system is equipped with a heating circuit that can warm up the system not only during operation, but also in stand-by or off mode. This circuit can be fed by an external power supply from a conventional 230 V socket, or by energy that the generator itself produces and stores in the battery (in stand-by mode). When the battery level drops, the system can then switch itself on and recharge the battery in stand-by mode.
This was the main focus of the test - we put H2BASE into storage mode, where it is necessary to maintain a stable internal temperature for safety reasons. "During the night we monitored the system temperature, the frequency of switching on the fuel cell heating and also the energy consumption of this heating," says DEVINN developer Jiří Vršínský. "In the morning, we then connected the thoroughly cooled system to our electric Nissan Leaf, and started charging. We considered the possible critical points to be in particular the drainage of reaction steam and condensed water, where freezing could occur, and we also needed to verify the functionality of all components integrated into H2BASE (DC/AC, charger, control units). We were also interested in the temperature behaviour of the components and their cooling."
During our test we had to focus on other parts of the system besides the fuel cell, whether it was the battery, cooling control, sensors or fans. "The morning after the main test, the sun was shining so much that the snow on the roof above our H2BASE started to melt and the dripping water fell directly on the radiator with the fans, where it froze again. We decided to take advantage of this and test the behaviour of the fans and cooling," explains Vršínský.[/vc_column_text][vc_column_text]Just in case of freezing or other forced stops, the fans are equipped with a protection system that protects them against damage. Once the water in the fan area began to freeze, the system successfully stopped the frozen fan until the entire system warmed up and the ice was released.
It is therefore possible to declare that H2BASE coped with all the obstacles we prepared for it perfectly. The heating circuit provided optimal conditions for securing all important parts of the system, especially the aforementioned fuel cell. But our temperature resistance testing is certainly not over - the system will certainly experience more extreme temperatures. However, these will have to be carried out in a climate chamber as the spring months approach.
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