Heat Networks Investment Project
The government is promoting district heating systems with its massive £320m Heat Networks Investment Project which opens for applications from the public and private sectors from Autumn 2018.
The idea of HNIP is to reduce carbon emissions from heating as the use of Combined Heat and Power ("CHP") engines in district heating makes fuller use of the inherent energy in gas: gas is used to generate electricity and the heat from generation is circulated as heat in large insulated pipes around a district instead of being wasted to the atmosphere.
However, the heat generated is likely to be wasted in summer and so CHP district heating does not always produce the benefits generously assigned to it. CHP is also based on combustion which not only emits CO2, it also emits NOx, SOx and particulates which are a serious risk to health in urban environments.
CHP for district heating has been overtaken by events
In practice the use of CHP for district heating has been overtaken by events. The successful programme to decarbonise the electricity grid means that the optimum route for decarbonising heating has moved from combustion of gas in district heating networks towards using heat transfer.
Much lower distribution temperatures are used in heat sharing networks – eliminating heat losses to the ground – where ground source heat pumps are used in each building to extract heat from the communal ground array whenever a building needs heating.
With improvements in the build construction of modern buildings, many commercial buildings need cooling in summer. A CHP district heating system is not able to provide cooling unless a second set of separate insulated pipes are installed to distribute cold water for cooling. This duplication is seriously expensive.
Fifth Generation District Heating and Cooling Network
There is a much more natural alternative: where ground source heat pumps have been installed in a fifth generation district heat network using ambient ground temperature distribution, the same heat pumps can be engaged in reverse to reject heat to the communal network and provide cooling.
Installation of District Heating and Cooling Systems based on Ground Source Heat Pumps.
To get the full benefit of a Fifth Generation District Heating Network you will need to employ someone with design and installation experience of integrated heating and cooling systems. A Fifth Generation District Heating Network may not perform well unless it is incorporated into a good design by someone who understands the needs of the buildings, the use to which the buildings is being put and the local geology.
For more information on installation of ground source heating and cooling networks from an experienced source please contact one of our members.
The Environment Agency encourages well-balanced Ground Source Heating and Cooling systems.
See Environment Agency position on GSHC