Archetech Issue 49 2020 | Page 81

“ 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. VIESSMANN Each apartment draws what it needs from the district heating system via a heat interface unit (HIU). The main plantroom 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-plantroom on the roof. 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. “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 base load 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. 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. www.viessmann-us.com PAGE 81 - ARCHETECH