Warming and the role of the plastic film insulation. After sunrise, with the gradual strengthening of sunshine, the solar radiation to obtain a film studio exceeds the thermal conduction and radiation heat, warming rapidly shed. Waning afternoon sunlight, heat over the resulting solar heat, Pengwen decreased. At this time the film is being drained by the greenhouse temperature, a phenomenon known as heat transfer. Also a 0.1 mm thick plastic film, thermal conductivity: 2.4 PVC, polyethylene is 2.9. Therefore, the insulation effect plastic polyvinyl chloride film greenhouses at night as well.

The thermal conductivity of the plastic film is small ((0.2-V0.6 kcal / m ² · h ℃) about glass (0.5 ^ -0.8 kcal / m L · hr · 0C) of 40-7O Yo. However, the use of film the thickness is 0.1 mm, the glass is only 1 / 20- 1/30, the absolute value of thermal conductivity is not small. Since the film of the longwave radiation transmittance than glass large, it is more insulation performance night poor at night when the temperature is too low easily lead to frost, daytime warming fast, and easy to cause harm to a high temperature.