District heating

La Cité Verte District – Québec City, QC

La Cité Verte – a large-scale, multi-residential project comprised of housing units, apartments, condos and townhouses – is the most advanced wood biomass-fired district heating system in North America.

La Cité Verte in Québec City, QC


La Cité Verte is the first large-scale, multi-residential project in Quebec comprised of green, intelligent buildings. There are more than 800 housing units – including condos, townhouses, apartments and affordable housing. La Cité Verte currently employs the most advanced biomass district heating system in North America for its space heating and domestic hot water (DHW) needs.


The Viessmann solution

At the heart of the system is a boiler plant housing four Viessmann Pyrotec KPT-1250 wood-fired boilers (each rated at 1,250 KW) in a 5 MW cascade system. The cascade arrangement provides maximum boiler plant efficiency with high turndown ratio (1:16) that precisely matches load. A 5.2 MW natural gas boiler provides emergency backup for the biomass boilers, and a 650 KW diesel generator will ensure continuous operation of the entire district heating system in the event of an electric power failure.


Installation details

The boilers heat two 22,000 L buffer water tanks before heated water (90°C supply / 50°C return) is distributed through a highly efficient, low temperature hydronic heating network for district DHW and space heating.

Pre-insulated underground piping in the 2.2 km system ranges from 8" in diameter exiting the boiler plant to smaller pipes feeding row houses (1" diameter) and other buildings throughout the site.

Substations in each Cité Verte building distribute the appropriate amount of heat and calculate fuel bills for the individual units. Water flow throughout the network is driven by a 25 HP pump in the winter and a 5 HP pump during the summer, when space heating requirements are significantly reduced. 

A Viessmann boiler control system integrates seamlessly with Smart Heat Network controls developed by Regulvar and project engineers Génécor and Poly-Énergie. The integrated system monitors the energy consumption data collected from individual units and district substations along with boiler data to optimize efficiency throughout the district.


The results

The Pyrotec hot water boilers have met their published performance ratings for combustion efficiency (up to 85%) since the biomass heating system went online in October 2011. When completed, La Cité Verte will use 30% less total energy than conventional developments.


Project details

Project year 2011


4 x Pyrotec KPT-1250
Custom Control System

Rated output

17,060 MBH / 5 MW


Bernard, Mercier, Drouin, Québec, QC

Developer construction manager        

SSQ Immobilier, Québec, QC

Renewable energy specialist

Poly-Énergie inc., Québec, QC


Génécor Experts-Conseils Inc., Québec, QC

Control systems

Regulvar, Laval, QC
TBC Constructions Inc., Québec, QC

Maintenance and operation

SSQ Immobilier, Québec, QC

Related References


Bluenose Academy – Lunenburg, Nova Scotia

The Bluenose Academy in Lunenburg, Nova Scotia is the first government building in the province with a fully-integrated wood pellet-fired biomass heating system. It is also the first building in Canada featuring a biomass heating system to obtain LEED® Gold certification.

Read more

Nazko Valley Elementary School and Community Centre – Quesnel, BC

The Nazko Valley Elementary School and Community Centre was retrofitted with a wood biomass heating system to achieve lower fuel costs and carbon credits from reduced greenhouse gas emissions.

Read more

Sustainable Wood Energy Project – Camrose County, AB

A self-contained wood biomass Energy Station provides space heating for the Camrose County Administration Office, with a gas-fired boiler acting as back-up during peak load times. By opting to retrofit the building with a wood-fired boiler, Camrose County was able to reduce its annual CO2 emissions by approx. 148 tonnes.

Read more
District heating

Fink Enderby District Energy – Enderby, BC

The Fink Enderby wood biomass district energy project serves ten residential, commercial and industrial customers. Primary heating is provided by a Viessmann Vitoflex 300-RF, KRT-540 (formerly Pyrot) rated at 1843 MBH. Back-up heating for peak loads is supplied by a Vitocrossal 200, CM2 (1078 MBH) gas-fired boiler.

Read more
How can we help?

Need help selecting the right product?

Find a product
Top links