Viessmann boilers and a Viessmann CHP unit have been specified to provide space heating and domestic hot water to 546 apartments at 101 George Street, the new residential development in Croydon, London, which has become the tallest modular building in the world.
Mechanical and electrical design contractor Red Electric chose Vitocrossal gas-condensing boilers over other manufacturers’ alternatives for their high efficiency and exceptionally low NOx emissions.
The heat interface unit (HIU)
101 George Street is a high-quality development of private rental and build-to-rent units comprised of two towers, one 38 story's tall and the other reaching 44 storeys. The apartments in this new south London landmark are connected to a district heating system that integrates the six Vitocrossal 200 CM2 620 kW gas-condensing boilers and a single Viessmann Vitobloc EM70 CHP (combined heat and power) unit.
Each apartment draws what it needs from the district heating system via a heat interface unit (HIU)
Each apartment draws what it needs from the district heating system via a heat interface unit (HIU). The main plant room is located two floors below ground level, but to accurately regulate heating-provision at the upper levels, some equipment is also located in a mini-plant room on the roof.
Boiler specifications
101 George Street’s developer specified that the boilers should be capable of providing double the forecast peak heat demand so that if one set of equipment should ever have to go offline to fix a fault, an identical set can immediately take over.
This high-level specification is typical of the entire development. All homes share amenities including a podium garden, roof-top gardens on top of each tower, a panoramic viewing walkway, gyms, and a residents’ lounge.
Reducing carbon emissions
“The highlight of the heating system is the integration of the two technologies,” said Viessmann Technical Director, Christian Engelke. “Installing almost 4 MW of heat generators and 'only' 115 kW of thermal heat output from the CHP involves careful planning. The boilers are sequenced by Viessmann’s Vitotronic 300 cascade controller, which ensures the system meets its target temperature. The CHP is designed as the lead generator providing the baseload heat; the boilers are then enabled appropriately when the building requires it.”
“It is envisaged that the CHP will contribute to a further carbon reduction of up to 30% by providing efficiently locally-generated electricity without losses,” concluded Engelke.
Less wastage
All levels above the first floor at 101 George Street have been formed from modules, more than 1,400 in all. These were manufactured in Bedford, where they were also fitted with electrics, plumbing, and windows.
This construction method produces 80% less waste than conventional building processes, requires fewer workers on site, and takes less time on site. From the start of construction to the first residents moving in took just 30 months.
