direct heat source

例句：

1. 1. The new solar panel is a direct heat source for the house.
   新的太阳能板是房子的直接热源。
2. 2.The car's engine uses a direct heat source to power its wheels.
   汽车的引擎使用直接热源来为它的轮子提供动力。
3. 3. The company's research focuses on developing new direct heat sources for energy efficiency.
   该公司的研究专注于开发新的直接热源以提高能源效率。