适宜收集稀薄的太阳热虽然太阳在地球每单位面积上的热量较小,但如果能收集起来,就有相当可观的热量可以利用。与有限的石油燃料相比,太阳能作为热源具有许多优点,既没有污染,又用之不尽。以往的牧草自然干燥,实际上就是太 Appropriate collection of thin solar heat Although the sun in the Earth per unit area of ​​?? less heat, but if it can be collected, there is considerable heat can be used. Compared with the limited petroleum fuels, solar energy as a heat source has many advantages, neither pollution, but also inexhaustible. Natural pasture pastures are actually too dry