Used in the presence of a central heating system with hot water. Hot water from the heating system goes through the primary circuit and warms the water in the secondary circuit coming from the pool.
They can be different in size, capacity and are calculated based on the size of the pool and on the electric power supplied by the heating system.
It consumes a significant amount of electricity, but it is profitable as an initial investment. It’s the perfect solution for heating of the small pools.