If the solar collector needs to be installed in a closed loop,a small 0.628m² copper coil heat exchanger can be provided in the bottom of the tank.This sized heat exchanger is more than ample,as the heat transfer from the solar collector is gradual and flow rates slow.A larger 1.256m² heat exchanger is fitted in the top of the tank if high demand mains pressure water heating is required.The copper coils provide excellent heat transfer,corrosion resistance and can withstand mains pressure water.