Fifth Generation Heat Networks
A fifth generation heat network is installed at the Balanced Energy Network at the London South Bank University. The trend towards lower temperature heat distribution arrives at its logical conclusion in Fifth Generation Heat Networks with heat distribution at ambient ground temperature: this eliminates heat losses to the ground and reduces the need for extensive insulation. Each building on the network employs a heat pump in its own plant room to extract heat from the ambient circuit when it needs heat, and uses the same heat pump in reverse to reject heat when it needs cooling. This allows waste heat from cooling to be recycled to those buildings which need heating on a "Heat Sharing Network". The overall temperature within the ambient circuit is controlled by heat exchange with an aquifer or another water source to remain within a temperature range from 10°C to 25°C.
A fifth generation network can service buildings of different designs from different eras. A modern building with a low temperature internal heat distribution system can use an efficient heat pump delivering heat output at 45°C. An older building with a higher temperature internal distribution system like radiators may need to use a high temperature heat pump to deliver heat output at 75°C.
Because a Fifth Generation Network avoids the use of combustion it emits no CO2 on site. It also has zero emissions of NO2, SO2 and particulate matter which is a key consideration in cities, like London, which suffer from high air pollution.
A Fifth Generation Heat Network can absorb and recycle waste heat within the district at any temperature above 25°C.
A Fifth Generation Heat Network is less expensive to install than earlier generations as it does not need heavy insulation for the piping circuits and does not need the space, or the cash, for installing a central "Energy Centre". It is also less expensive to run as it eliminates heat losses to the ground and the administrative cost of collecting large fees from buildings on the network as they bear their own costs of the heat pumps in their own buildings.