Maidstone prison hot water calorifier

HMP Maidstone has successfully used ENiGMA on two calorifiers producing hot water for the domestic services for one of the prison blocks.

The system incorporates a 2" common cold water-feed, a 4" flow to hot water services and a multi-secondary return. Also steam-fed nest elements are used for heating water.

Due to hard water, the calorifiers and associated pipework had become encrusted with scale, and the nest element was so badly scaled-up that its efficiency had been drastically reduced. Descaling the calorifiers and pipework at Maidstone Prison had been carried out on a regular basis using acid and mechanical descaling methods.

ENiGMA was fitted onto a cold water feed and in order to monitor performance, a low range evaluation unit was installed onto the multi-secondary return. This enabled physical comparisons to be made between the treated and the untreated nest-heating elements.

After 12 months the treated calorifier was opened and the nest element was found to contain only a small amount of scale deposit that was soft and could be removed by hand. It was noted the entire system was gradually being descaled, resulting in increased efficiency and considerable savings in energy and maintenance.

By comparison, the untreated calorifier contained much larger scale deposits and the nest element required acid treatment to facilitate scale removal.