Heat networks suffering from poor water quality

Poor water quality leading to plant failure, pipe replacement and shortening of the system’s life

Credit iStock.com - Wweagle

Around one in six district heating and cooling systems could have significant issues with water quality, according to a major survey of 185 heating and cooling systems in the UK.

The study, presented by Jon Greaves, national technical manager at Hydro-X Water Treatment, found that 28 networks had major problems with poor-quality water. This was leading to plant failure, pipe replacement, inefficient heat transfer, and a shortening of the system’s life.

Twelve systems had poor-quality water at handover, while four experienced full loss of system water because of corrosion and scaling. Incorrect dosing with a high-PH solution led to the corrosion of aluminium plate heat exchangers in three of the latter systems.

At the CIBSE Technical Symposium Greaves revealed that four combined heat and power (CHP) systems and two biomass boilers had never been switched on and had not been decommissioned properly.

He identified a number of key findings across design, pre-commission and management, including no consideration of the metallurgy of the system, no pre-commissioning cleaning, and system leaks not being monitored.