General information on gas engines

Combined heat and power generation

The expression means that electrical power and heat are generated simultaneously from the same source of energy, namely burning gas in the gas engine, driving a generator by that and utilizing with high level of efficiency the heat output of the gas engine. Components of the heat energy are the cooling water, lubricant, utilization of the combustion gas and the cooling of the turbo charger. Generally the ratio of electrical power and heat is 40/60 percent depending on the model.
The gas engine is a special Otto-cycle engine the rotational energy of which is transformed to electrical power by a generator. It does not need high pressure gas supply; the normal supply line can provide its operation. The main advantage of it is that the loading can be changed in wide range without significantly reducing the total efficiency. The performance range of gas engine models varies from kW to MW. It's possible to construct modular systems and continually enlarge them. The operation of gas engines can be provided by remote surveillance. It is a reasonable solution for those who need both electrical power and heat energy. It is also useful for those who would like to control and monitor their power generation on their own and comply with environmental regulations. The combined power generation with a gas engine is practically utilized in areas where electrical power, heating and cooling is needed simultaneously, and the equipment operates at least 6500 hours in a year.

The generated electrical power can replace bought electrical power and the excess can be sold to the local electrical utility service provider.
The generated heat (i.e. 90°C or 127°C water) can be used for producing sanitary hot water throughout the year, heating in winter or cover our industrial or agricultural needs for heat. The fuel of gas engines is primarily natural gas, but organic gas or propane can also be used.

Combined power generation based on natural gas as main source of energy is the solution for those who:

  • would like to provide their energy supply with favourable economic conditions,
  • seek after continuous and high quality power generation,
  • require long term and highly effective operation,
  • would like to have active environment friendly policies,
  • would like to control and manage their power generation and consumption on their own.

The fuel of the gas engine can be:

  • natural gas,
  • liquid gas,
  • wood gas,
  • organic gas,
  • waste dump gas,
  • mine gas (pit gas).

Advantages of combined heat and power generation:

  • 86% of the energy input can be utilized,
  • 37% of the available energy is electrical power and 49% of it is heat energy,
  • contrary to electrical power generation abroad (condensing power plant) or separate heat generation (boiler, heating plant) the fuel (natural gas) need is reduced by 35% and less carbon dioxide and waste heat causing greenhouse effect is emitted to the environment,
  • the investment returns in 3-5 years depending on the level of utilization,
  • the gas engine provides 97% availability meaning that it operates reliably on long term (15-20 years).

The comparison of combined power generation and traditional power generation methods shows significant saving in favour of combined power generation.

Scope of application:

  • sanitary hot water generating equipments of distant heating networks,
  • hospitals,
  • office buildings of public institutions,
  • larger hotels,
  • swimming pools, thermal bathes,
  • food processing plants (milk, meat, etc.),
  • chemical plants,
  • agriculture: greenhouses (vegetable and flower producing), temperature controlled fish farming.


The formerly described combined heat and power generation complemented with absorption cooling. It means that the gas engine heating-cooling-power generating unit can be better utilized. Besides electrical power generation which is performed by the gas engine-generator unit the available heat can be utilized for both heating and cooling. Cooling performance is 70% of the heat output. Trigeneration makes possible to continually maintain electrical power generation practically throughout the year for 7800-8200 hours.

Working principle of a trigeneration gas engine system

Advantages of trigeneration:

  • see the advantages of combined heat and power generation,
  • higher level of utilization due to cooling in summer,
  • broader scope of application.

Scope of application

  • shopping centres,
  • cultural institutes (cultural centre, theatre, etc.),
  • office buildings of public institutions,
  • hotels,
  • hospitals,
  • food processing plants (milk, meat, beer, canned food, etc.),
  • cold-storage houses,
  • chemical plants.

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