high pressured solar water heater

We supply high pressured solar water heater with coil exchanger inside water tank. It works well, people like it because when people turn on the tap, there is immediately hot water. Because hot water flow in this end, and hot water come out that end. The water in the tank is hot, when cold water go through the copper coil, it warms. The copper is about 40 meters long in the tank. And the water people use is so clean because people use the water directly from the tap,not from the tank. People only use the temperature of the water in the tank.