What makes a cylinder compatible with a heat pump?
Basically as the DT is 5 and the flow rate is increased. You need a higher surface area from which to transfer the heat. A traditional heating coil is rated at DT20.
High Gail Solar
– Juoule HP twin coil has upper coil surface area of 2.53m2, and lower coil surface area 0.78m2
Solar Thermal Twin Coil
– For example stelflow twin coil has upper coil surface area of 0.55m2, and lower coil surface area 0.78m2
source: Joule