Research On Performance Of Passively Controlled Light Transmitting Device With Bimetal

This study proposes a bimetal passively transmissive device.This device adopts bimetal as an important component of the automatic brightness adjustment in the device,and uses the nature of changing the bending angle when the bimetal is heated to realize the function of increasing or decreasing the penetration or blocking of sunlight according to the solar radiation intensity and the outdoor temperature.The purpose of indoor solar radiation reduces summer glare and air conditioning energy consumption.The light-transmitting device can adjust the light environment and the thermal environment in the building without requiring complicated control equipment,and reduces the cost of the adjustable sunshade facility.(1)This paper firstly introduces the working principle and experimental conditions of the passive transmissive device of bimetal.The dimming mode experiment is divided into 12 kinds,and the heat transfer experiment condition is divided into 9 types.(2)The dimming performance of the translucent device was tested by constructing the experimental room and the contrasting room.The contrasted rooms were divided into two types:unobstructed and blind shelter.The effects of different room dip angle and room length-width ratio on the adjustment characteristics of the translucent device were analyzed.And under different working conditions,the change of the opacifying rate of the light-transmitting device and the comparison of the illuminance of the experimental and comparison room were studied.Studies have shown that in terms of illumination adjustment,the aspect ratio of the room has a great influence on the opacifying rate of the translucent device,and the change in the angle of the placement of the room also directly affects the opacifying rate of the translucent device.(3)Then the heat transfer performance of the light transmission device was tested by increasing the temperature measurement points in the experimental room and the comparison room.Three typical experimental cases,case3,case4,and case7 were analyzed to analyze the different ventilation channel widths and vent widths of the device.The effect of the temperature distribution on the room.Based on the measured temperature data and air flow rate data,the natural heat convection away from the experimental room was calculated to obtain the working condition.case 7 has the best effect of reducing heat transfer.Studies have shown that in terms of temperature regulation,the temperature in the ventilation channels and in the room of the experimental room where the device is applied is significantly lower than that of the comparison room in the solar radiation stage.(4)Finally,the dimming performance of the translucent device was studied using the TracePro software.The simulation model of the translucent device was established and the optical distribution characteristics of the room were simulated.The actual simulated light output obtained was basically the same as the shading rate obtained by the experiment.Then,the lighting conditions of the human office area and the distance from the inner surface of the transparent device to the depths of 0.44 m and 0.66 m are analyzed and studied to obtain the best indoor lighting position.The bimetal passively transmissive device proposed in this paper can be applied not only in urban buildings,but also in solar greenhouses.Through the precise adjustment of the coupling of brightness and heat flow,a suitable growth environment for plants in the greenhouse can be achieved.