Improvement of Individual Solar Heater Efficiency

We analyze the efficiency of solar heaters, and how usual existing ones operate in a range corresponding to an important loss of efficiency between clear weather and covered weather operation. This gives its interest to a simple solution to avoid a "threshold effect" pointed out in our analysis of standard heater operation. In short, this consists in warming, in the solar collector, the cold water input instead of cycling the water at the balloon temperature. This results in a significant reduction of the collector average temperature, which explains the corresponding thermal losses reduction.