A freshwater hatchery of a leading independent salmon producer uses water from a nearby river to supply its tanks, where salmon eggs are grown and hatched.
It is critical that the hatchery keeps the temperature of the tank water stable to ensure the eggs grow and hatch in line with productivity targets.
One winter it became apparent that the cold ambient temperature was causing the temperature of the freshwater feeding the tanks to drop. As a consequence this was causing the spawning and hatching process to slow down.
Aggreko was contacted to provide a heating solution to warm-up the tank water and regain productivity levels.
Aggreko provided a 1.5 MW diesel boiler and heat exchanger solution to raise the water temperature to around 14°C.
Water from the river was sent through shell and plate heat exchangers, where it was warmed-up to the target temperature prior to entering the hatchery tanks.
To make the system as energy efficient as possible, a heat recovery system was added, using an additional heat exchanger. This was integrated at the point where the warm water left the tanks prior to returning to the river. It could then recover the excess heat from the water and channel it back for use in the primary system.
Using the recovered heat a continuous temperature was maintained with the need for only three 250 kW boilers instead of four. As an average boiler uses approximately 3000 litres of diesel per week, this saved the customer £1200 per week in fuel costs.
A further two boilers were kept on stand-by to ensure flexibility should the heating capacity need to be increased or decreased with the ambient temperature. In addition, due to the remoteness of the site it was critical to have redundancy - should one boiler fail, another could simply be plugged in to ensure continuity.
A data logger was initially used to set the system up and ensure it ran at its optimum efficiency. By using flow and temperature to calculate the megawatt needed, the data logger helped make sure the heat recovery system was generating the predicted cost saving.
A 125 kVA diesel generator was used as the power supply for pumps and controls.
Why was Aggreko chosen?
The Aggreko team has extensive technical know-how in the aquaculture sector and has worked with the customer over a number of years to deliver a solution that not only meets the technical needs of each project, but also provides cost savings at the same time.
Aggreko has over 30 years experience providing turn-key solutions to fish farms and hatcheries across the UK and Scandinavia.
Their expert team assists fish farmers overcome a number of challenges - from providing supplementary or emergency power to remote locations, to ensuring stable critical water temperatures during seasonal changes.