SAV helps low temperature heat network deliver major energy savings

The Project

Gun-WharfAn SAV LoadTracker CHP unit serving Danfoss FlatStation heat interface units (HIUs) in a low temperature heat network is saving £3,600 per annum on energy costs at the Gun Wharf housing development in East London.

Gun Wharf is a multiple award-winning development by A2 Dominion Housing Group, comprising 121 apartments and commercial space in Bethnal Green. Sustainability is a key element of its design and consulting engineers Hill Partnerships designed a district heating system for the apartments with CHP as the predominant heat source.

They also adopted a low system temperature design, in accordance with the latest CIBSE guidance for heat networks. Consequently, the design flow and return temperatures are 70°C and 40°C respectively, compared to the 80°C/60°C traditionally used in the UK. The design also takes full advantage of the modulation capabilities of LoadTracker CHP units, tracking electrical demand to maximise CHP run-times. Since commissioning the 15kW LoadTracker has contributed 95% of the building’s electrical load, modulating down to the site’s average 8kW electrical demand as required.

The combination of load tracking CHP and low system temperatures achieves significant energy savings compared to a traditional gas fired boiler and mains electricity configuration. As well as reducing energy costs by £3,600 per annum, the system has reduced the development’s carbon footprint by over 18,800kg of CO2 per annum (compared to traditional designs).

The Challenge

To reduce heat network temperatures and reduce CO2 emissions.

The Solution

To supply and install a 15kW LoadTracker CHP unit able to supply 95% of the building’s electrical demand. The low return temperatures are facilitated by the installation of a Danfoss FlatStation HIU in each apartment, which maintain a high temperature differential (ΔT) across the primary circuit to maintain low return water temperatures.

Summary of Site Demand

Annual electricity demand………73,300 kWh
Electricity price (Day tariff):………9.619 p/kWh
Electricity price (Night tariff):………6.245 p/kWh
Gas consumption………543,542 kWh
Gas price………2.57 p/kWh

Carbon Footprint Savings

18.8 tonnes of CO2 emissions has be reduced by installing a CHP system relative to a conventional mains supply/gas boiler system.


This is an equivalent 12.9% reduction of CO2 emissions!


Cost Savings

The use of LoadTracker CHP has resulted in annual savings of over £3,600 relative to a conventional mains supply/boiler system.


This is equivalent to saving 18% on energy bills!


CHP Features & Benefits


  • Modular Unit Design for flexibility of install.
  • LoadTracker automatically modulates electrical output, which minimizes unnecessary grid electricity consumption.
  • Noise levels of 49db comparable to low level office noise.
  • Long service intervals (8,000 hours or 2 years).
  • Carbon footprint savings
  • Cost savings

Danfoss FlatStations Features & Benefits


  • Optimized for low temperature heat networks
  • Maximum 25°C system return temperatures from DHW production
  • Complete pressure and temperature control
  • Dynamic self-acting system balancing valves
  • Maximum end-user comfort
  • Minimized legionella risk
  • Certified to Swedish F:103-7e standard for district heating substations