Residual heat from the air inside the trailer, and heat in the insulation and inner lining of the trailer.
拖车里的空气所带来的余热，以及拖车里的绝缘层和内衬里的热量。
2
It is dependent on the temperature differential between the inside and outside air, type and thickness of insulation, and the area of the conducting surfaces.
这个主要取决于内外空气的温度差、绝缘层的类型和厚度以及传导面的面积。
3
A view that is more common in factories or warehouses of exposed pipes wrapped in silver insulation and metal air vents can be seen suspended from the ceiling in the pictures.