Salmon eggs don’t like the cold. When the temperature drops, they take their time to grow and hatch – a problem on a fish farm with strict productivity targets. Out in Tullich, Inverness, a salmon farm that relies on nearby river water to supply its tanks was suffering the effects of a colder-than-usual winter. With the lower temperatures of the incoming river, spawning and hatching of eggs had become too slow.

By passing the river water through shell and plate heat exchangers before it entered the tanks, our system had the water up to a balmy 14°C in no time at all – ideal hatchery conditions.

By using an additional heat exchanger to recover the excess heat from the water leaving the tanks, our system was remarkably energy efficient. It meant we only needed three 250 kW boilers running, instead of four. We kept two boilers on stand-by in case conditions got worse or one of the operating boilers failed. Powering the system was a 125 kVA diesel generator.