屋顶全开启型Venlo式温室的采光性能

不同天气（晴天和阴天）和开窗比例条件下，对屋顶全开启型Venlo式温室(温室A)白天室内、外光合有效辐射量子通量密度（PAR）进行测试。以屋顶通风窗型Venlo式温室为对照（温室B），研究屋顶全开启型Venlo式温室的采光性能。结果表明：屋顶全开启型Venlo式温室在晴天条件下的平均透光率为53.7%，阴天条件下为52.1%，均高于对照。且屋顶全开启型Venlo式温室的透光率随着（屋面）天窗开启比例的增加而提高，而对照透光率无明显变化，表明开启的天窗减少了对太阳辐射的阻挡，提高了温室透光率。同时，屋顶全开启型Venlo式温室晴天条件下PAR分布均匀度均值为0.893，阴天条件下为0.916，均低于对照。不同天气条件下，随着天窗开启比例的增加，屋顶全开启型Venlo式温室PAR分布均匀度不断降低，而对照无明显变化，且屋顶全开启型Venlo式温室在晴天条件下PAR分布均匀度变幅大于阴天，表明开启的天窗集中阻挡了温室天沟附近太阳辐射的直射，从而导致其PAR分布均匀度较低。

Study on the Lighting Performance of Open roof Venlo Greenhouse

Under different weather (sunny and cloudy) and different window-opening proportions conditions, the photosynthetically active radiation intensity （PAR）was tested inside and outside of two greenhouses (A is a Venlo greenhouse with a open-roof, B is a Venlo greenhouse with a roof vent window) in order to study the lighting performance. The result showed that under sunny and cloudy conditions, average lighting transparent rate of the open-roof greenhouse were 53.7% and 52.1%, while those significantly higher than the greenhouse B under the same conditions. Whether sunny or cloudy conditions, the lighting transparent rate of the open-roof Venlo greenhouse increased as proportions of window (roof) increased. And there was no significant change in the greenhouse B. It showed that the open-roof Venlo greenhouse had higher lighting transparent rate, while opened window (roof) reduced solar radiation blocking. Under sunny and cloudy conditions, the mean value of PAR distribution uniformity coefficient (PDUC) of the open-roof Venlo greenhouse were 0.893 and 0.916, which were lower than the value of the greenhouse B under the same conditions. As proportions of window (roof) increased, the PDUC of the open-roof Venlo greenhouse reduced, of which variable amplitude on a sunny day was larger than cloudy. At same time, the PDUC of the greenhouse B had no obvious change. This showed that opened window of the open-roof Venlo greenhouse had blocked the direct solar radiation near the gutter, which lead to a lower PDUC of the open-roof Venlo greenhouse.