Solar house heating

Contemporary standards of living have been realized through technologies that depend especially on the conventional mineral fuels, coal, oil and gas.These minerals account for three quarters of all energy utilized throughout the world.'Another fifteen percent comes from vegetable matter, 2 which (in the form of wood) was the most important source of energy a century ago.The remainder of the energy is derived from falling water, atomic energy (through conversion to electricity), direct muscular efforts of man and draft animals and from other unclassified, largely noncommercial, sources.Direct uses of solar energy are limited to recovery of salt from brines, drying of food products, scattered practical applications in hot water heating and salt water distillation, and a wide range of semi-experimental applications, of which space heating is one.Other uses take the form of focusing systems for high temperature research, satellite power units, terrestial power units and home cookers.The United States space program has provided the financial support for research on very small power units, and spin-offs for terrestial applications can be expected in the communications field.Whether large scale terrestrial uses of solar power will eventually materialize is more conjectural.Financial support for research on this topic is almost nonexistent, though practical solar power would be at least as important to the underdeveloped sun-lit regions of the world as civilian atomic power, which we have already spent billions of dollars to develop.