Abstract: A solar heating system includes a solar collector comprising a continuous length of copper tubing coiled into a helical array of closely adjacent turns and supported within a sealed housing. The outer turns of the array are fabricated of tubing having a greater diameter than the tubing which forms the inner turns of the array, and the total length of the larger diameter tubing in the array is greater than that of the smaller diameter tubing. The relationships beween the tubing diameters and lengths are selected to achieve a desired flow rate and temperature rise for the overall array. The array is supported within the housing by copper sheets which also operate to eliminate moisture condensation within the housing.

Abstract: A solar heating system of the closed type comprises a solar collector, a water storage tank, and water lines therebetween. The solar collector preferably comprises a continuous length of tubing coiled in a helical array of closely adjacent turns, having a water inlet communicating with the outermost turn and a water outlet communicating with the innermost turn. Comparatively cold water is taken from a water outlet adjacent the bottom of the storage tank and is pumped through a line to the water inlet of the solar collector, and heated water is supplied from the solar collector water outlet, together with cold water from an external supply, to a common inlet adjacent the top of the storage tank. The water line between the solar collector water outlet and the tank water inlet includes a U-shaped section disposed external of the tank and having legs at least equal to the height of the tank, to provide a heat trap which minimizes the loss of heat from the tank.