Heat Networks for the 21st Century

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What we offer for heat networks is several years ahead of everyone else.

Not only have we perfected the arts of heat exchange, thermal storage and pipe sizing, but we have also mastered IoT technology, adding a layer of open-source logic control and communications to networks.


First on the menu are the HIUs.

  • Best in the industry for 3 years running now, since independent BESA test records began. That is not a fluke.
  • Electronic control with comprehensive functionality that can be customised when needed.
  • 3 years of inclusive contract-free GSM connectivity via ANY mobile network - working out the box. This provides two-way communications covering both HIU and heat meter functions, via the standard MQTT protocol as well as integration with all common database types.
  • No requirement for any metering or communications infrastructure, saving significant installation time and costs while making the system as suitable for existing housing stock as for new-build. Data collection and prepay hardware is independent of billing service provider, with connection made in the cloud. This allows billing companies to be switched when needed.
  • Automated and remote commisisoning, indluding generation and emailing of commissioning reports at various stages of contract. Special functions such as screed drying, or pre-handover full load simulations, can be managed remotely.
  • Fit and forget. HIUs will communicate alarms when needed, including blocked strainers, and have no annual maintenance requirements.
  • Communication of differential pressures to energy-centre for pump control, removing the need for sensors on the network.
  • Managed keep-warm facility, removing the need for thermal bypasses on the network.
  • Managed load control with network wide hot-water priority, reducing pipe and buffer size requirements.

Pumping Stations

The main control functions on a heat network are pressure and temperature control. This is independent to heat generation, which is a seperate function.

The purpose of pressure and temperature control is to ensure every property receives enough heat when required, while minimising pump energy and supply temperatures as far as possible. This is a balancing act between pump heat and heat source selection (temperature control), based on the current load on the system and feedback from remote differential pressure readings at index points.

We have now linked these pump and temperature control functions to the data supplied from HIUs, to provide a turn-key control solution.

  • A single pre-assembled pump and valve group, fully functional out of the box.
  • Standard 180kPa Magna3 pumps, sutable for networks from 2 to 1000s of properties.
  • Full range rating down to suppling a single tap, or dead head (no flow) conditions. This turn-down enables a single set to drive all the circuits in a building.
  • One second resolution monitoring history to ensure problems such as pumps hunting can't occur.
  • Pump redundency, using single head pumps that can be individually isolated for maintenance (unlike twin head pumps).
  • Control redundency, using a seperate controller and power supply for each main pump.
  • Fully managed pump control, based on current network loads and DP readings from HIUs, with fallback to local DP control.
  • Heat source selection between high (e.g. boiler), medium (e.g. heat pump) and low temperature (return) sources. The high and medium temperature inputs would normally connect to the appropriate buffer stores. A typical temperature profile would be 65C when <0C external, 55C Summer peak, 45C Summer overnight.
  • Heat meter(s) included. The system performs daily energy accounts combining data from HIUs with data from the supply heat meter, and any block entry meters, to calculate pipe losses and bypass flow accross the network.
  • Touch screen for HIU management, linked before delivery to HIU cloud network so HIUs appear as they are powered up.


A substation introduces heat exchange (and pressure isolation) between sections of a heat network. It is effectively a pump station, with the additional plate heat exchange functions added, as well as options for primary side shunt pumps.

We have standardised the sub-station functionality, allowing heat exchange stations to be combined with the pump stations and water quality stations to create a complete sub-station assembly that covers all the functions for connected sub-networks of various sizes.

Simple Pipework Design

Having sat on the CIBSE pipework technical group and contributed significantly to the latest guidance on pipe sizing, we are well placed to say what works and what complies. Our defautlt pipe sizing strategy follows latest guidance in spirit as well as in dettail, and also significantly reduces costs.

  • Peak load design temperature of 60/30C at 0C external temperature.
  • Instantaneous DHW loads based on DS439 using the equivalent number of 38kW blocks of load, and using latest guidance on HIU sizing limits more in line with combi-boiler sizing.
  • 150kPa accross network. 50kPa for network, 50kPa for pipework in buildings, and 50kPa for load (HIUs).
  • Flow pipes are sized in buildings to <= 1.5m/s (at full diversified load), with 50mm insulation.
  • Return pipes in buildings sized to > 0.5m/s (at full diversified load), with 20mm insulation.
  • Network pipes sized to 50kPa drop plus any left over from the 100kPa for buildings, using 200Pa/m as a starting point (i.e. 125m run from energy centre to building). Building level shunt pumps used at entry point where wider network requires up to 200kPa (500m distance to index building).
  • 45C (flow limited) thermal bypasses located 10 litres (flow pipe content) upstream from index property connection.