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Combined heat and power – generate power while you heat

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Vitovalor PT2 fuel cell heating appliance

Generating electricity also generates heat. In central power stations, this is lost as waste heat – and usually has to be cooled with additional energy too. With the principle of combined heat and power (CHP), on the other hand, systems use the waste heat for heating and domestic hot water. Therefore, their overall efficiency is much higher than when electricity and heat are generated separately. In addition, there are no losses during energy transfer. This is due to the electricity being generated where and when it is actually needed. Based on the CHP principle, Viessmann offers two different, highly efficient technologies that meet different needs:

  • Fuel cell heating system
  • CHP units

Decentralised power generation is becoming increasingly important

The energy transition and rising electricity prices make the decentralised generation of electricity ever more important. Wind farms and photovoltaic systems have been built in large numbers to replace nuclear power stations and conventional large scale power stations. However, because energy production fluctuates and thus cannot be planned, controllable CHP systems are important building blocks towards achieving a successful energy transition. When there are shortages in fluctuating electricity generation, systems with combined heat and power can make an important contribution to covering demand. Because this happens locally and the power is generated on site, this also reduces pressure on power grids. Generating your own electricity is now a viable replacement for drawing power from the grid.

Combined heat and power generation: economy and investment

With a CHP system, you save up to 40 percent energy, drastically reduce CO₂ emissions and thereby make an important contribution to climate protection. A further benefit that arises from the use of this innovative technology is greater independence from power supply utilities and their rising electricity prices. If you consume the energy you are generating, it will cost you only about one third of the normal electricity rate. In addition, the surplus power is fed into the grid and remunerated.

Principle of combined heat and power generation based on the function of the fuel cell

Fuel cell heating system

In contrast to previous gas appliances, the fuel cell uses the energy input electrochemically and no longer for combustion processes. Both heat and electricity are generated from the hydrogen contained in the natural gas by means of electrolysis. Only water is emitted during the combined heat and power generation process in the heating system. Better for the environment and protects finite resources. Viessmann micro CHP systems with fuel cells are also suitable for use in detached and semi-detached houses.

This is how environmental protection works

Hydrogen and oxygen are all that is needed to generate heat and power. The chemical reaction between the two substances forms the basis of what is sometimes referred to as "cold combustion". It occurs between two electrodes: hydrogen is conveyed to the anode, where a catalytic converter splits it into positive ions and negative electrons. The electrons travel to the cathode via an electrical conductor, causing electrical current to flow. At the same time the positively charged hydrogen ions reach the cathode through the electrolyte (an ion exchange membrane), where they ultimately react with oxygen to form water. Heat is released. The entire process is completely free of pollutants and is environmentally responsible.

For Viessmann, innovating without giving top priority to reliability and durability would be unimaginable. With the fuel cell heating appliance, Viessmann once again turned to proven technology. This is why the Vitovalor PT2 (formerly Vitovalor 300-P) was developed in cooperation with Panasonic. Panasonic has manufactured more than 34,000 appliances in series production for the Japanese market. 

Gas-operated combined heat and power unit

A gas driven combined heat and power (CHP) unit generates heat and power simultaneously. Depending on the output, it is suitable for larger residential buildings and residential complexes as well as for commercial enterprises and municipal projects. Since the output is designed according to the base load, the average heat demand over the year, a CHP unit in residential buildings is often combined with a peak load boiler. This provides sufficient heat even in winter. Both heat generators are connected to the heating system in order to provide heating water or DHW in this case.

Gas driven combined heat and power (CHP) unit

Different output sizes ensure high levels of economic efficiency

Compact Vitobloc 200 appliances are designed as decentralised CHP units with a bias towards heating. These comparatively small units generate electricity according to the combined heat and power generation principle for consumption on site. The heat that is generated by this process is used simultaneously, almost without losses, for heating. Any power not required is exported to the public grid and the power supply utility provides remuneration accordingly. Because of their great flexibility combined with maximum efficiency, CHP systems already perfectly complement the fluctuating energy generation from the sun and wind. In addition, the systems are available in different versions and output sizes. They can therefore be optimally adapted to the respective requirements and are a guarantee for long term economic efficiency.

More information and product range

Product range

Make yourself more independent from external power supply utilities and rising prices – with this innovative way of generating power. Viessmann has more than 25 years of experience in the field of efficient gas-operated CHP systems. Alongside standard products, the company also manufactures CHP units tailored specifically to customers' individual needs. Depending on the type, these can be operated with natural gas and/or liquid gas without any problems. The power spectrum ranges from 6 to 530 kWel or 15 to 660 kWth.  

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