Cogeneration system

Cogeneration systems






context of application

Cogeneration systems



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Grupel carried out yet another special project, this time using a system of simultaneous production of two or more types of energy – a Cogeneration project.

A regular generator transforms the chemical energy that exists in fossil fuel (diesel, gas, biogas, among others) into electrical energy. Usually, through the combustion of the first, thermal energy is produced which then is transformed into mechanical energy inside the internal explosion engine. In turn, mechanical energy is transformed into electrical energy by means of the alternator.

The output in the production of electricity, in this type of power plants, does not exceed 45%, being, normally, between 35% and 40%. The rest is released into the atmosphere in the form of exhaust gases, through chimneys.

On the other hand, a cogeneration system is based on the use of waste heat so that there is no loss of a large amount of energy. Thus, this different concept of energy use raises the overall performance of the group to values that can range between 75% and 90%.

When organizing a project of this dimension, the different thermal power and electricity requirements of the installation must be analyzed. In order to maximize the economic profitability, the type and size of the generator must be adapted to satisfy the total thermal requirement, using the electrical power to export to the electricity grid.

Since these projects aim at continuously producing energy (24h / 365 days), in general, fuels that optimize operating costs (OPEX costs) are used, as is the case of natural gas. The use of this fuel also results in a reduction in toxic emissions.

A recent cogeneration project fully developed by Grupel had the following characteristics:

  • Motogenerator powered by an MTU natural gas engine, with an electrical production capacity of 1,500kW | 480V | 60 HZ;
  • Heat exchanger:
    • Tubular exchanger with Bypass valve in exhaust circuit for thermal recovery of 939kW thermal;
    • Plate heat exchanger in high temperature refrigeration circuit for thermal recovery of 873kW thermal;
    • The total recovery capacity will be 1678kW maximum, provided through a secondary plate exchanger with water inlet at 75ºC and outlet at 88ºC, with a flow rate of 137 m3 / h;
  • Pump system for high and low temperature circuits. Since this system is critical, a system of redundant pumps has been designed in both circuits;
  • Compensation cooler. This system guarantees the operation of the electric generator when there is no partial or total use of the generated heat. This system is assisted by motorized 3-way valves, a complete instrumentation system for data acquisition and a control system to guarantee the correct functioning of the system;
  • Gas supply ramp and valves associated with the cut;
  • Automatic system for oil filling, with an additional 500 liter clean oil tank;
  • Exhaust catalyst for reducing exhaust emissions in the form of NOx and evacuation chimney;
  • Associated systems for ventilation, cooling the electrical room and fire safety.


The entire system was designed based on the usual Plug & Play criteria using a 40-foot soundproof container (High Cube). All the elements are integrated into the interior and the roof, so that, once assembled, they form a single unit. With this, we highlight some advantages:

  • It facilitates sea and land transport;
  • It minimizes construction works on site. The customer only needs a concrete threshold to support the complete system. Grupel also provided this design and its construction;
  • It minimizes on-site assemblies. The customer only needs to connect the electric cable and the heat recovery tubes. Grupel prepared the connection and all the documentation associated with the assembly and connection;
  • It facilitates the start-up of the group on site with associated tests, since the group comes from Grupel’s factory completely assembled and tested before its shipment. Grupel provided the customer with all the documentation associated with the operation and maintenance;
  • Grupel can additionally offer full operation and maintenance services for this type of systems.


As it is such a complex project, and since Grupel always seeks to provide the best service and the necessary support to each client, we also provide additional documentation that clarify the project and all its specifications.

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