Viessmann's Vitotwin 300-W and Vitobloc 200: Efficient heating and power generation from
natural gas and biogas
Compared with conventional power plants, the crucial advantage of combined heating and power (CHP)
units is that the heat produced during the power generation process can be put to good use. This makes
them particularly efficient. They consume up to 25 percent less primary energy than conventional power
plants and their CO2 emissions are around a third lower. The German government has therefore defined
its objective as being to double the proportion of CHP stations used for power generation by 2020.
All-inclusive range with combined heating and power units from 1 to 401 kW e
Apart from highly efficient condensing systems, biomass boilers, heat pumps, solar and photovoltaic
systems, Viessmann also offers appliances and systems for the combined generation of heat and
electricity. These include the Vitotwin 300-W micro CHP system that produces 1 kW of electrical energy
and 26 kW of thermal energy for use in single and two-family homes. The Vitobloc 200 combined heating
and power units manufactured by ESS GmbH, a member of the Viessmann Group, are capable of
producing up to 401 kW of electrical energy and 549 kW of thermal energy. These are ideally suited for
apartment blocks, hotels, commercial and industrial buildings, as well as for use in local heating networks,
and they can be fuelled by natural gas, bio-natural gas or biogas.
Viessmann also offers a complete range of heating system components to supplement the factory-tested,
fully wired Vitobloc 200 CHP units, including heating water buffer cylinders and remote monitoring
systems – everything from a single source and perfectly synchronised with one another.
Schmack and BIOFerm, both companies in the Viessmann Group, both specialise in systems used to
generate biogas, an ideal fuel for the Vitobloc 200 CHP units.
Vitobloc 200 CHP unit and bio-natural gas in a package
Viessmann is now offering its Vitobloc 200 CHP unit in a package with a supply agreement for
environmentally compatible bio-natural gas as part of a completely new concept. Apart from reducing
environmental impact, this concept can also prove to be particularly lucrative for the user. According to
EEC directives and regulations, electricity generated by combined heating and power station fuelled by
bio-natural gas brings a much higher return when fed into the public grid than electricity produced from
fossil natural gas – for 20 years at guaranteed prices.
At the same time, as far as the CHP unit user is concerned, bio-natural gas is just as easy and
uncomplicated to obtain as electricity from renewable energy sources. Biogas suppliers, such as farmers
and power supply companies, produce biogas from renewable raw materials, upgrade it to the quality of
natural gas and feed it into the supply grid. The CHP unit user obtains his gas from the grid in the usual
way. His bio-natural gas supply agreement is accompanied by certified proof of origin containing details of
the quality and quantity to be supplied. This is acknowledged as a green certificate and is regarded as
being a supporting document for remuneration for the electricity generated with bio-natural gas.
Once signed, the agreement guarantees delivery of bio-natural gas over a period amounting to at least
ten years. This period may be extended to 20 years as an expedient alternative, however, in order to take
full advantage of the guaranteed feed-in rates laid down by the EEC.
The innovations at a glance
Viessmann is introducing a number of innovative CHP systems:
Vitotwin 300-W, the innovative Stirling-based micro CHP system for single and two-family homes.
The Vitobloc 200 mini CHP module EM-5.5/12, with a 6000-hour maintenance interval.
The Vitobloc 200 CHP module EM-20/30, which utilises condensing technology.
The Vitotrans 200 AC flue gas/water heat exchanger for utilisation of condensing technology with
the Vitobloc 200 CHP units up to 401 kW el.
Vitobloc Gateway for integration of Vitobloc 200 CHP units into Viessmann's Vitocom 300
Vitotwin 300-W: the innovative CHP system for single and two-family homes
Most of the combined heating and power units used up to now have been larger CHP stations, which
have been primarily installed in commercial and industrial premises. Viessmann is now offering a compact
natural gas fired micro CHP system that enables the use of this efficient technology in single and
two-family homes with the innovative Vitotwin 300-W.
Double benefits that are worthwhile
The power produced by the Vitotwin 300-W during heat generation covers the home's basic demand
and reduces the amount of electricity provided by the power supply company. Produced and used in
the home, the owner also receives remuneration for this electricity. If the Vitotwin 300-W produces
more power than can be used at any one time, it is fed into the public grid. The owner also receives
money for this - at the current rate of 10 euro cents per kilowatt hour.
Efficient generation of heat and electricity
The Vitotwin 300-W is a combination of free-piston Stirling engine and a highly efficient gas fired
condensing boiler, both accommodated in a compact wall mounted housing. The free-piston Stirling
engine has no crankshaft and runs in a hermetically sealed system with helium as the working
medium. The movement of the working piston is converted into electrical energy in an integrated linear
generator, the waste heat produced by the engine is used to heat the rooms in the house and for
domestic hot water heating. The 6 kW th thermal output and 1 kW el power output correspond to the
usual basic demand of single and two-family homes. The overall efficiency achieved by the Vitotwin
300-W amounts to 96%.
The integrated gas fired condensing boiler with the established and proven MatriX gas burner and
stainless steel Inox-Radial heat exchanger supplies up to 20 kW additional thermal output to cover
demand peaks on particularly cold days and for rapid DHW heating. The condensing boiler achieves
98 percent standard efficiency by using the heat of condensation.
Compact, easily installed and easily serviced
The scope of delivery of the Vitotwin 300-W not only includes the Vitocell 340-M combi cylinder but
also a remote monitoring system. The wall mounted micro CHP unit fits into confined spaces with its
compact dimensions (height x width x depth: 900 x 480 x 480 mm). The appliance weighs around 100
The Vitotwin 300-W is just as easily installed as any conventional wall mounted gas fired boiler. It has
similar connections and flue gas routing – the Stirling engine and integrated gas fired condensing
boiler share both gas connection and flue gas system. This means that there is no extra installation
work. An electrician is merely required to install the power connection. There is no need for an
After-sales service for the Vitotwin 300-W is just as easy as the installation of the appliance. Service
for the peak load burner corresponds to that required by a normal wall mounted, gas fired condensing
boiler. The Stirling engine is maintenance-free. It does not require either filters or lubricants as all of
the moving components run in helium inside the hermetically sealed housing.
The innovative Vitotwin 300-W micro CHP system will be available as of September 2011.
Vitobloc 200 EM-5: a new mini CHP unit with particularly long maintenance intervals of up to 6000
The Vitobloc 200 EM-5 mini CHP unit closes the gap between the wall mounted Vitotwin 300-W micro
CHP system and the Vitobloc 200 EM-20 with its 5.5 kW el and 12 kW th output. The 6000-hour
maintenance interval is exceptionally long. This means that the Vitobloc 200 EM-5 only requires
maintenance once a year at most. The Vitobloc 200 EM-5 also runs very quietly thanks to its 3-cylinder
Integrated condensing technology
The CHP unit achieves 96 percent overall efficiency by virtue of the integrated condensing technology.
The flue gas heat exchanger has been incorporated into the engine's internal cooling circuit to prevent
failures due to poor quality heating water, corrosion and cavitation. 50 to 100 modulation contributes
towards energy-saving operation.
Satisfies the demanding connection requirements of the power supply companies
The alternating current of the CHP unit must be synchronised with that of the mains supply in order to
maximise the performance capacity of the grid. Power supply companies frequently impose
particularly stringent requirements in this respect. The Vitobloc 200 EM-5 satisfies even the most
demanding technical connection conditions, with its synchronous generator and intelligent control
system permitting variable adjustment of the mains phase shift (cos phi).
In the event of a power failure, the Vitobloc 200 EM-5 switches over to emergency standby mode
Integration into building management systems
The control system of the Vitobloc 200 EM-5 can be integrated into the Vitocom TeleControl system
for remote monitoring. This gives the user a standard, comfortable user interface when operating
several appliances at the same time. There is also an interface to the building management system.
Complete technical equipment
The scope of delivery of the Vitobloc 200 EM-5 includes a complete set of technical equipment, with
electricity meter and flexible gas, flue gas and heating water connections. This saves time and money
during the planning, installation and commissioning processes. A sound insulation hood is available for
installations in areas that are critical in terms of sound levels, such as hospitals or schools.
Vitobloc 200 EM-5 will be available as of 2012.
Vitobloc 200 EM-20: new CHP unit that utilises condensing technology
With the new Vitobloc 200, module EM-20/39, Viessmann is offering a fully wired CHP unit for use in
large apartment blocks with 30 to 50 accommodation units, hotels and commercial buildings. The
electrical output amounts to 18 kW with 39 kW thermal output. The maintenance interval amounts to 6000
hours – without the need to top up with oil in between – which is three times longer than the intervals for
previous appliances – and makes the Vitobloc 200 EM-20 a particularly economic unit to run.
High efficiency thanks to the utilisation of condensing technology
By utilising condensing technology, the mini CHP unit is extremely efficient, achieving up to 96%
overall efficiency (Hi). Condensing technology is utilised by cooling the flue gas from the four-cylinder
engine in the flue gas heat exchanger to such an extent that the water vapour in the gas condenses.
The additional heat produced in this process is output to the heating system.
Meets even the most demanding connection conditions
The new Vitobloc 200 EM-20 also satisfies the particularly stringent technical connection conditions
imposed by the power supply companies for synchronisation of the fed-in alternating current with the
mains current. The CHP unit's synchronous generator and intelligent control system enable flexible
adaptation of the main phase shift (cos phi).
Time-saving installation thanks to comprehensive standard equipment
The new Vitobloc 200 EM-20 is supplied as a fully wired compact module with comprehensive
standard equipment following functional testing in the factory. The equipment supplied with the
Vitobloc 200 EM-20 includes the sound insulation hood, the integrated flue gas cleanup system and
the control system. The mini CHP unit is also equipped with all of the components required for
emergency standby operation as standard, so that the unit can be installed particularly quickly.
Viessmann's new Vitobloc 200 EM-20 CHP unit will be available as of September 2011.
Vitotrans 200 AC: new downstream heat exchanger for utilisation of condensing technology with
Viessmann is now offering specially adapted flue gas/water heat exchangers for every Vitobloc 200 CHP
unit with 50 to 401 kW power output to enable utilisation of the heat produced during condensation of the
water vapour in the flue gas from CHP units. By utilising condensing technology, the downstream tube
bundle heat exchanger ensures that the CHP unit is particularly efficient. The new Vitotrans 200 AC
increases thermal output by up to ten percentage points.
Particularly large stainless steel heat exchanger surfaces enable maximum condensation rates, even at
low return temperatures, such as the 25 to 30 ° usually encountered in swimming pools.
Installation and maintenance
The design of the Vitotrans 200 AC permits time-saving installation of the heat exchanger. The vertical
installation requires very little space and enables excellent condensate run-off. This prevents deposits
forming on the heat exchanger surfaces to keep heat transfer efficient on a long term basis. If the unit
needs cleaning occasionally, this may be performed quickly and easily thanks to the easily accessible
smooth heat exchanger tubes.
The new Vitotrans 200 AC condensing heat exchanger will be available as of April 2011.
Vitobloc Gateway: new interface for integration of Vitobloc 200 CHP units into Internet TeleControl
Everything under control – wherever you are. The new Vitobloc Gateway now offers a means of
incorporating the control system of the Vitobloc 200 CHP units into the Vitocom 300/Vitodata 300 Internet
TeleControl systems. It enables property management companies, contractors and service providers,
who already use the Internet TeleControl system to monitor boiler systems, to also monitor all of the
important CHP system data remotely.
The new Vitobloc Gateway can be installed inside the Vitobloc 200 control cabinet to save space or
separately, on the Vitocom 300 top-hat rail, for example.
The new Vitobloc Gateway will be available as of April 2011.
Other Vitobloc 300 CHP units in the all-inclusive Viessmann product range
Vitobloc 200 EM-50/81
4-cylinder gas engine, output: 50 kW el / 81 kW th, efficiency: 90.3% (Hi).
Vitobloc 200 EM-70/115
6-cylinder gas engine, output: 70 kW el / 115 kW th, efficiency: 90.7% (Hi).
Vitobloc 200 EM-140/207
6-cylinder gas engine, output: 140 kW el / 207 kW th, efficiency: 90.4% (Hi).
Vitobloc 200 EM-199/263
6-cylinder gas engine with turbocharger, output: 199 kW el / 263 kW th, efficiency: 89.6% (Hi).
Vitobloc 200 EM-199/293
6-cylinder gas engine with turbocharger, output: 199 kW el / 293 kW th, efficiency: 89.0% (Hi).
Vitobloc 200 EM-238/363
12-cylinder gas engine, output: 238 kW el / 363 kW th, efficiency: 90.1% (Hi).
Vitobloc 200 EM-363/498
12-cylinder gas engine with turbocharger, output: 363 kW el / 498 kW th, efficiency: 89.7% (Hi).
Vitobloc 200 EM-401/549
12-cylinder gas engine with turbocharger, output: 401 kW el / 549 kW th, efficiency: 92.7% (Hi).
Fig. 1: Viessmann's innovative Vitotwin 300-W micro CHP system generates heat and electricity
particularly economically in single and two-family homes.
Fig. 2: The Vitobloc 200 EM-5 mini CHP unit closes the gap between the wall mounted Vitotwin 300-W
micro CHP system and the Vitobloc 200 EM-20 with its 5.5 kW el and 12 kW th output. The 6000-hour
maintenance interval is exceptionally long.
Fig. 3: The Vitobloc 20 EM-20/37 is a new Viessmann mini CHP unit with three times the normal
maintenance interval, now extended to 6000 hours.