The Citigen combined heat and power network supplies heating to landmark buildings within the City of London including the Guildhall, Barbican Arts Centre, Museum of London and Smithfield Market through over 5Km of below ground MTHW distribution mains routed through underground service tunnels and basement car park areas.
 
Overall system load analysis and pumping strategy development work was carried out to confirm the need for a new self contained 9MW gas fired MTHW boiler plant ensuring stability of system operation during periods of peak heat demand or in the event of the main CHP generation plant needing to be shut down for maintenance.
 
Control and hydraulic interface parameters within existing buildings were established and an operating protocol then developed to provide for Guildhall `island site` operation as well as import from, or export of supplementary heat onto, the main district heating network.
 
Careful system integration and space planning were essential to ensuring that existing occupied buildings were kept operational at all times.
 
Detailed discussions with the system operator allowed a dual permit to work maintenance regime to be put in place which coincided with the parallel roll out of a new system wide PLC based control and monitoring system.
 
Significant amount of site survey work and subsequent rationalisation of existing heating circuits resulted from this exercise with differential pressure valve control adopted generally on all main plant connections to ensure that heat energy use was optimised.

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​This work was funded by the Corporation of London to ensure security of heat energy in line with connected user requirements.