In this page we describe, briefly, the architecture of our Fuel Cells Systems, you can refer to the page Hydrogen Fuel Cells Technology, for general information about fuel cell systems, while you can refer to the page Fuel Cell Electrochemical Reaction, for more details about the theoretical functioning of the “Hydrogen Fuel Cell” we use in our systems.
General description of our Fuel Cell Systems
The diagram below shows the “general functional diagram” of our Fuel Cell Systems, divided in the main functional blocks.
Fuel Cell Stack
This is the core of a Fuel Cell System, where the electrical energy is generated. It is formed by a “series” of fuel cells and, to be able to work properly, it needs to receive a continuous stream of Hydrogen and Oxygen and in exchange it generates electrical energy.
During its normal running, the Fuel Cell Stack produces also thermal energy, that we need to extract, in order to keep its working temperature, to the desiderate value.
Central Electronic Control Unit
It is the brain of the system, that coordinates all the activities of the machine. It receives the commands directly from the machine user, and then, giving the perfect timing to all the operations can smoothly run the system. Furthermore, through the use of predictive algorithms, it can anticipate the requests of the user, optimizing the use of resources and giving to the user a fluid control feeling.
Thanks, to a powerful CPU, to an extensive network of accurate sensors and actuators, to the use of specific algorithms and advanced control strategies, customized for every machine, it can keep the system always working at the top of the performances. In addition, a complete set of Built-In Self-Test functions can detect any anomaly on the system, at the very beginning, allowing us therefore, to act on it in advance, avoiding so costly “machine downtime”.
Hydrogen Management/Recirculation System
In order to keep the Fuel Cell Stack working properly, we need to provide Hydrogen in excess, in respect to the amount of hydrogen that is effectively used. Of course, the hydrogen is our fuel and we do not want to waste the hydrogen that has not been used, then we keep the hydrogen in continuous recirculation, adding from the hydrogen cylinder, the amount of hydrogen that has been effectively used.
Air Management System
Also in this case, in order to keep the Fuel Cell Stack working properly, we need to provide Oxygen in excess, respect to the amount of Oxygen, that is effectively used. In the case of the Oxygen, considering that we take it from the air, we can just discharge the amount of air that get out of the Fuel Cell Stack.
Cooling Management System
In order to keep our Fuel Cell Stack to the right working temperature, we use a liquid, that passing through the Fuel Cell Stack, can drain the excess heat, and then this liquid, passing through an heat exchanger, can release the excess heat to an external fluid that can be, for instance, air or sea water.
When the temperature of the stack is below of the desired temperature, using the same liquid, we can heat the Fuel Cell Stack keeping it always working in the best conditions.
DC-DC Converter
The voltage that get out from the Fuel Cell Stack depends on the number of Fuel Cells used and on a number of other factors, including the amount of current used in the specific moment, therefore, for applications that require a controlled value of the output voltage, a “DC-DC converter” module is used, which is able to receive a pretty large range of input voltages, giving as output the value of voltage required.
Inverter (DC-AC Converter)
In most cases, we use electric motors that work with an AC Voltage, therefore we need to convert the DC voltage, we receive from the Stack/DC-DC Converter, to an AC Voltage usable to drive the electric motor.
The inverter can also include directly a “DC-DC Converter” as input circuit.
Main Components Description
Following the description of the main components we use in our Fuel Cell Systems.
Fuel Cell Stack
This is the core of a Fuel Cell System, where the electrical energy is generated. A single Fuel Cell, through an electrochemical reaction can generate a DC electric energy with a theoretical Voltage of about 0.7V*. This value of voltage is usually very low in respect to the applications we need to carry out so, in order to reach an higher voltage value, more fuel cells are assembled together (in “series” connection) in a stack, in order to reach an higher value of voltage that can reach hundreds of volt.
* the voltage of a fuel cell change in function of a number of factors, including the amount of current we are using.
Filters
A set of filters is used to clean the hydrogen and oxygen, which we supply to the Fuel Cell Stack, especially from some contaminant substances, which can greatly reduce the features and the life of our system. In the case of the hydrogen in particular, have a clean fuel at the origin is essential, for instance, an hydrogen produced with a process of electrolysis of the water is usually really clean.
Sensors
An extensive network of accurate sensors allow us to keep the system always under tight control. In this way we can know how every part of the system is working at every time, and so, we can keep it always running with optimal performances. In this way we can also detect any anomaly on the system, at the very beginning, and we can therefore intervene in advance, avoiding so costly “machine downtime”.
Humidifiers and Water Separators
The electrochemical reaction that takes place in the fuel cell transforms “hydrogen + oxygen” in water. Then the right balancing of the amount of water contained in the Fuel Cell is essential to the performances and life of this component. The Humidifier allows us to maintain the correct amount of water where it is needed. The Water Separator allows us to extract excess water where it is not needed.
Pumps, Blowers, Compressors, Valves
In order to keep “moving”, in the wanted way, the fluids (hydrogen, oxygen and refrigerant solution) that we use in our system, we need to use a set of pumps, blowers, compressors and valves, obviously specific for the single application.
An accurate and stable control of the flowing of the fluids is essential to our system.
