Braithwaite House Tower Block
Building: Social housing refurbishment
Products: Ensbury pressure jet boiler, Chesil pressurisation unit
Application: Space heating 1,020kW
Braithwaite House in Islington, London, had been facing problems with their current boilers and heating system.
Reaching 55 metres tall with 19 floors consisting of 108 dwellings, this residential building needed a boiler that was long lasting and could cope with the high demands placed on it.
Two Ensbury low temperature 510kW boilers, with matched Riello RS modulating burners using natural gas, were specified for the project. CBS Maintenance Services Ltd installed the boilers along with a floor standing Chesil pressurisation unit and expansion vessel to maintain the correct pressure in the system for water to reach the highest radiator in the building. Sandy Yogendra, mechanical design engineer at Islington Council, commented,
“We had numerous problems with the previous boiler so turned to Hamworthy to provide us with a reliable, long lasting and high efficiency boiler solution. The Ensbury boilers suited the brief perfectly.”
As part of the heating system replacement the plant room was moved from the rooftop of the building to the ground floor; enabling it to support the weight of the steel shell boilers. This had implications for the flue which now needed to have a 50m riser due to it being installed in a residential area. Sandy worked closely with Hamworthy and Midtherm to install a flue system that would run the full height of the building.
A combined flue with a draught stabiliser was installed with twin wall insulation to maintain internal stack temperatures whilst ensuring exposed surfaces are safe to touch. The flue was powder coated to suit the exterior of the building - helping it to blend in. Sandy went on to say,
“There were many practical obstacles to overcome in relocating the plant room, but the whole project went smoothly and we are very pleased with the outcome.”
Hamworthy’s Ensbury LT pressure jet boiler range comprises 3 models with outputs from 440kW to 580kW, for use with fully modulating or high/low matched burners, delivering operating efficiencies up to 95 per cent net (86 per cent gross) at part load.
Enabling return water temperature to reach as low as 15°C without condensing, and with no minimum flow rate, the steel boilers provide versatility in system applications.
Ensbury LT boilers from Hamworthy feature a three-pass heat exchanger, which has been designed to reduce the level of NOx. With a range of low NOx matched burners the boilers achieve up to European Class 5 performance.
The thermal mass within the Ensbury boiler can accommodate fluctuating operating conditions, and with no minimum water flow requirement, eliminates the need for a shunt pump, simplifying the hydraulic system design. A high level of insulation also ensures very low standing losses at just 0.15 – 0.5 per cent.