Wharncliffe Gardens Estate comprises of 288 dwellings spread over 11 blocks. Approximately 47% are private leasehold, with the other 53% occupied by residents of City West Homes.

The original heating and hot water systems comprised of a ‘Harco-Pack’ utilising a 117 litre indirect copper cylinder and tap-stat. The heating zone valve was controlled by a mechanical room thermostat that served radiators through a one-pipe system.

A single boiler house comprising of four gas fired boilers each rated at 570kW, provided primary district heating to three satellite plantrooms. This buried pipework that served these plantrooms was approximately 40 years old, leaking and in disrepair. The works consisted of modifying the boiler room Low Loss Header to incorporate the installation of a new district underground manifold. Modifications were made to each satellite plantroom to accept the new size pipe work. Plate heat exchangers then transfer the load from the primary to the secondary district heating circuits serving all dwellings with heating and hot water.

PHASE 1
A trench was excavated from the boiler room to each satellite plantroom to carry the new district heating pipework. Casaflex™ Uno, manufactured by Brugg Pipe Systems, was specified and delivered in 120 meter bundles. Given the external pipe diameter of 202mm and each coil weighing over 1 tonne, we designed a bespoke turntable capable of carrying the load and uncoiling it safely into the trench. In total over 0.6km of Casaflex™ pipework was laid.

PHASE 2
288 Heat Interface Units (HIU) were installed with individual heat metering. The heating system is controlled by programmable room thermostat and thermostatic radiator valves (TRV) with hot water delivery of 44kW (35⁰C rise @18 litres/min).

All heat metering information is collected via cable from each HIU meter into hubs strategically placed around the estate. This information is transmitted via wireless connectivity to CityWest Homes’ centralised hub for billing purposes and energy monitoring.

PHASE 3
To ensure each HIU had an adequate water flow of 18 litres/min and a minimum 2.5 bar pressure the water mains across the estate had to be upgraded. This was achieved by installing 1km of MDPE underground pipework throughout the estate, terminating with external isolation valves; 84 new copper risers were installed across 11 blocks and 288 flats. To facilitate this phase of the project we had to excavate a large proportion of the site which in turn required a comprehensive traffic management and pedestrian plan. We collaborated with Thames Water Development Services, the utility company responsible for the City of Westminster highway connections.

H&V nominated District Heating Project of the year 2017
L8 Chlorination and legionella compliant
Individual remote smart metering
Collaboration and management of various utility service providers with pro-forma payments

RESULTS
Heat Networks (Metering & Billing) Regulations 2014 compliant
A 20% percent increase in efficiency with a cost saving of £30k in year one alone
High level of customer satisfaction in comparison to all other major works – 82% in comparison with 59%
Greater system performance for end users with an increase of hot water delivery from 4 litres/min to 18 litres/min

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CLIENT: City West Homes

PROJECT: Wharncliffe Gardens Estate, District Heating & Flat Works (P133b)

VALUE: £2.25m

PERIOD: 2016-17