“…5 m3/m2 collector in the lower 49 United States, and around 0.7 in Denmark (68,69). With modern tank technology (70,71) priced at � $21-34/m3 installed, for sizes of the order of 102-1OIm3, storage accounts for only 10-1 of total capital cost, and heat costs with $150-200/m2 installed collector-system prices compete with marginallO sources (2,55).…”