Scheme of a simple plant

Well-designed plants use at the same time these both outputs, for heat and power. Co-generation is applicable in the power blocks of power plants with gas turbines, while so-called small co-generation is applicable in the small plants. Power can be used in the summer period for cooling in various processes and for air-conditioning.

Consumption of primary sources of energy is reduced by 40% and CO2 emission by 60%, while, at the same time, the investment per generated kWh is 3 to four times lower than at classic power plants. A period for return of the investment is usually shorter than four years.

Co-generation is used in the European countries mainly in industrial processes, power blocks of power plants, district-heating systems, holiday hostels, hotels, health services, housing units, schools, universities, gardening for green houses and waste treatment.

Fuel Cells
Fuel Cells are devices that convert a fuel's chemical energy, through electrochemical reaction, directly into electrical energy without combustion and pollutants.

They consist of two electrodes in electrolyte. Hydrogen is brought to the anode and oxygen to the cathode. Electricity is generated through electrochemical process while co-generation plant produces heat.

Hydrogen can be obtained from various hydrocarbon fuels, and natural gas is suitable because of its high content of methane.

Scheme of Fuel Cell

The Fuel Cell itself has no moving parts and it is therefore a quiet and reliable source of energy. It does not wear out and operates like continuous battery as long as it is supplied with fuel.

The use of Fuel Cells is particularly suitable for heating systems and water heating in family houses, dwelling houses and small settlements.

Nowadays, motor vehicles are probably the most interesting field of application of Fuel Cells, whereby the focus is on making smaller the size of motor and of fuel tank.


Natural Gas Vehicles
Natural gas as fuel for motor vehicles is used either as liquefied natural gas (LNG) or as a fuel for Fuel Cell. By combustion of liquefied natural gas, unlike other usual fuels such as gasoline or gas oil, the emission of pollutants is much lower, first of all that of nitrogen and sulfur compounds. A possibility for ozone to appear in lower layers is reduced by more than 50%, nitrogen oxide and carbon monoxide emission by 80%, whilst sulfur compounds, benzene, aldehyde and solid matters (soot) emissions are minor.

In addition to environmental advantages of LNG, the use of LNG as fuel for motor vehicle has also economic advantages.

Table: Comparative prices of developed power of engine by fuel (the data refer to Germany, 1999)

Natural gas vehicles are used mostly in the companies like public utility companies, public city transport, taxi traffic, post offices, delivery and other companies providing services, while the use of natural gas for passenger cars is still unusual. The mounting of gas-fired drive for passenger cars is usually ordered separately or it is mounted later on, but it is produced also in-line. The existing gasoline engine can easily be converted to gas engine without taking many measures, but there are often dual fuel engines (engines using two types of fuel, i.e. gasoline and natural gas).

Natural gas vehicle

Air-conditioning
Techniques of applying natural gas for air-conditioning are known, accessible on the market and competitive compared to other techniques. Absorption technologies with one, two or three cycles, compressor techniques combined with gas engine or heat pump and cooling systems based on dehumidification have been developed.

The price (compressor technique is cheaper by 40%), lifetime (absorption technique 20-30 years) and maintenance costs (minor at absorption technique) are the factors that influence a decision.

The same device can be used also for heating.

Vegetable Growing and Horticulture
Heat, humidity and carbon dioxide contained in the combustion gases can be used to speed up the growth and increase the yield of a greenhouse.
The temperature is maintained at a certain level, whilst CO2-content helps assimilation and its concentration in the greenhouse is maintained at a level of 0.3 to 0.4%.

A greenhouse

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