Fuel cells are a promising, durable, reliable and environmentally friendly source of electrical energy. A fuel cell (or as it is also called an electrochemical generator) is a device that converts the chemical energy of a fuel into electrical energy during an electrochemical reaction. Ideally, hydrogen is necessary for the fuel cell to operate as a fuel supply. However, the production and storage of such fuel is quite expensive. Therefore, "portable" fuel cell generators operate on hydrogen-containing fuel. As such fuel, we can use the usual hydrocarbons: methane, butane, propane, methanol, gasoline.
When using hydrogen as a fuel, products of a chemical reaction, in addition to the desired electricity, are heat and water. In this case, such a generator is absolutely harmless to the environment. When hydrocarbons are used as fuel (for example, propane), oxides of carbon and nitrogen will also be released into the environment. However, their value is significantly lower than during normal combustion.
Device and principle of operation
The fuel cell generator consists of:
- fuel processor
- power generation sections
- voltage converter
The fuel processor converts the hydrocarbon fuel to hydrogen, which is necessary for the electrochemical reaction (reforming). The main element of the device is a reformer. For example, natural gas entering a reformer reacts with water vapor at very high temperatures (about 900 ° C) and high pressure in the presence of a catalyst (nickel). The steam required for the conversion is formed from condensate due to the operation of the fuel cell. At the same time, heat is used, also released as a result of its work.
The power generation section is the main part of the generator. It consists of a variety of fuel cells whose electrodes contain a platinum catalyst. With the help of these cells produces a constant electric current.
Voltage transformer. The direct current produced by the fuel cells is unstable, has a low voltage and a high amperage. To convert it to alternating current, which meets the standards, as well as to protect the electrical circuit from various failures, a voltage converter is used.
In such a generator, about 40% of the energy of a hydrocarbon fuel can be converted to electrical energy. Also, another 40% of the energy of the fuel is converted into thermal energy. It can be used for heating the room, and the same water in the water supply. Therefore, the total efficiency of such a generator can reach 80%.
The advantage of a fuel cell generator is:
- may be a source of electricity and heat supply;
- high efficiency of 50%. And if you use the heat obtained as a result of the work, then all 80%;
- lack of vibrations and noise;
- minimum amount of pollutants;
- reliability (no moving parts)
- ease of operation
Disadvantages and features:
- relatively high cost;
- hydrogen is used most efficiently as a fuel;
Manufacturers of accessories for caravanning became interested in fashionable and modern technologies and released several of their developments.
The German company Truma, specializing in gas and electric caravanning devices, together with the IMM Institute of Microtechnique, developed the Truma VeGa fuel cell power generator. The idea was to make an affordable generator on a new, increasingly popular fuel cell technology for the mass consumer. The system received a silver F-CELL award in 2007 and an award at the Bavarian Energy exhibition in 2008. The general public tech product was presented at the exhibition Caravan Salon in 2012 in Düsseldorf. In the same year, its mass production and sales started.
To generate hydrogen and then convert it into electricity, Vega uses liquefied petroleum gas (propane / butane). The maximum performance of the device is 250 W / h or 6 kW / day. Thus, VeGa makes it possible to use simultaneously a multitude of energy consumers in a mobile home. From standard, filled with propane, 11 kg. balloon, VeGa is able to squeeze up to 28 kW of electricity. Thus, depending on the electricity consumption, you can live independently for up to several weeks.
The system works fully automatically. As soon as the battery voltage "sags" below normal, the Vega turns on and charges the battery with current up to 20 A. The correct charging current can be adapted to different types of batteries (acid, alkaline, helium). After reaching the optimum voltage at the battery terminals, VaGa returns to standby mode. Also, the VeGa fuel cell generator can be forced to start. The color touch screen displays all the necessary operating parameters: charging current, battery voltage, and working intervals.
The advantage of this system over other alternative energy sources (solar panels and wind generators) is the availability and relative cheapness of the raw materials used (propane / butane gas), stability at any time of the day in a wide temperature range.
And now about the sad. The market value of Truma Vega in the Movera catalog was 7,000 euros. Too high price for new technologies, even for a European caravan. Sales were very sluggish. Truma VeGa disappeared from the pages of directories in 2015. Today, Truma is trying not to recall this system.
EFOY has succeeded in developing and selling fuel cell generators. The main difference from Truma Vega is that the quality of raw materials (fuel) EFOY generators use methanol (methyl alcohol CH₃OH). Methanol is sold by the manufacturer in canisters 5 and 10 liters. (the price in the Movera catalog is 30 and 45 euros respectively). 5 liters of methanol is enough to generate 5.5 kW of electricity.
For motorhomes and caravans EFOY produces 3 types of generators:
- Comfort 80. Maximum power - 40 watts. Capacity - 80 Ah per day. Charging current - 3.3 A. Cost (Movera) - 2600 Euro
- Comfort 140. Maximum power - 72 watts. Capacity - 140 Ah per day. Charging current - 6 A. Cost (Movera) - 4000 Euro
- Comfort 210. Maximum power - 105 watts. Capacity - 210 Ah per day. Charge current - 8.8 A. Cost (Movera) - 5600 Euro
The same as VeGa, the EFOY has an automatic charge-keeping function on the battery and is activated only when necessary.
Dignity. The generator is silent and environmentally friendly. It produces only heat, water vapor and very little carbon dioxide. It works regardless of the time of day in the temperature range from - 10 ° C to +40 ° C.
EFOY also produces Pro series generators for industrial scale.
Disadvantages. still not resolved fuel cell pricing problem. As a catalyst in the cells of fuel cells use expensive material - platinum, which of course affects the price.
It should be noted that methanol fuel cells are engaged, in addition to EFOY, by a large number of companies. Toshiba introduces compact methanol fuel cells to power players, phones and laptops. Ethanol fuel cells are by far the most likely replacement for conventional batteries.