The Hot Debate
Fourth Generation District Heating
Wednesday 19 June 2019
26 Store Street, London WC1E 7BT
9.30 to 14.00

The Hot Debate on Fourth Generation District Heating took place on Wednesday 19 June 2019 at The Building Centre, 26 Store Street, WC1E 7BT.


The UK district heating industry is at a key junction in its journey – with HNIP funding announcements due in 2019, calls for legislation for consumer protection and the recent announcement to ban gas boilers from 2025 in new builds, there is a lot of focus on low carbon heat networks. It is important for the whole industry to focus on district heating design in order to improve the efficiency of planned and existing heat networks to reduce costs, reduce carbon emissions and reduce NO2 emissions.

The Hot Debate explored Fourth Generation district heating and the trend toward lower heat delivery temperatures down to 65°C and consequently lower heat losses to the ground. It also explore the next logical step in Fifth Generation District Heating and Cooling with distribution at ambient ground temperature to eliminate heat losses to the ground and eliminate the need for, and cost of, a central "Energy Centre". Instead, each building installs a heat pump in its own plant room to transfer heat from the network when its building needs heating, and to reject heat to the network when its building needs cooling.

The reduced complexity and cost of Fifth Generation district heating – which can also provide cooling – are expected to reduce the formidable barriers which have prevented Fourth Generation district heating networks being adopted in the UK.

The reduced CO2 emissions of Fifth Generation systems and the reduced NO2 are a by-product of a system which is not based on combustion, but employs heat transfer instead.

Fifth Generations systems also have the ability to recycle waste heat at any temperature above ambient ground temperature, including the heat that is the by-product of cooling from those buildings which need cooling.

Fifth Generation systems also have the ability to expand in modular fashion as new and existing buildings are ready to join a 5G network. This contrasts with the inflexible nature of 4G systems which must be planned long in advance to match a specific set of buildings and consequently require the signing of very long term contracts.