What key data are mainly referred to when choosing classroom lighting fixtures?
In order to make the classroom light environment reach a good level, the work we need to do mainly includes two parts: first, select reasonable lamps, which means that the lamps have high efficiency, high glare quality level, and reasonable light distribution curve shape; two , Carry out scientific design analysis, install lamps according to different classroom environments, and finally make the light environment of the entire classroom meet the requirements of relevant architectural design standards.
When we choose classroom lights, we mainly refer to the following key data:
1. The efficiency of lamps. The efficiency of a luminaire is simply the percentage of the luminous flux emitted by the entire luminaire to the luminous flux emitted by all the light sources of the luminaire. It is an important parameter to measure whether a lamp is energy-saving. The higher the efficiency of the lamp, the more effective the lamp can use the luminous flux of the light source; on the contrary, the lower the efficiency, the more energy is wasted.
2. The light distribution shape of the lamps. The light distribution shape of general small grille lamps is cosine light distribution. Most of the lamps we tested are cosine light distribution (as shown in Figure 1). The maximum light intensity of this kind of lamps is basically under the lamp, and the luminous flux is relatively Concentrate on the part under the lamp, and the light intensity to the side is very low. If you want to achieve the higher illuminance uniformity required by the standard, you can only increase the number of lamps used. Otherwise, there will be a bright and dark interval in the classroom, and the illuminance uniformity will be low. In addition, there is a lamp with a larger grille, and the light distribution shape can be made into a bat-wing light distribution (as shown in Figure 2). The maximum light intensity of this type of lamp is not under the lamp. Taking Figure 2 as an example, the maximum light intensity of the lamp is in the 45° direction. Compared with the cosine light distribution lamp, this lamp can make the illumination in a larger area uniform. to a higher level.
3. The glare quality level of the lamps. From the test results, it can be seen that the glare quality level of small grille lamps is generally better than that of large grille lamps. Generally, small grille lamps can reach class A when 500lx≤use illuminance≤1000lx, while most of the large grille lamps only reach class A when 300lx≤useful illuminance≤500lx.
Large grille lamps and small grille lamps have their own advantages and disadvantages. How to choose the right lamp during classroom installation has become the key. The standard stipulates that the average illuminance of ordinary classrooms should reach more than 300lx, which is an easy requirement for both types of lamps. According to the statistics after large-scale testing, the average illuminance of most classrooms exceeds 300lx. Qualified classrooms account for no more than 2% of the total number of test classrooms.
The characteristics of large grille lamps are: good uniformity, which can meet the minimum requirements of illuminance value and illuminance uniformity under the condition of relatively low power density, but the glare is high; the characteristics of small grille lamps are: glare control is good, but uniform The performance is poor, and the power density value required to meet the minimum requirements of illuminance value and illuminance uniformity is too high. How to achieve an average value of 300lx or more while ensuring that the illuminance uniformity is above 0.7 (Note 1) and the power density is below 9W/m2 (Note 1). The author believes that the power of a single lamp can be reduced at the same time on the basis of small grille lamps, that is, the use of single-tube small grille lamps. Under the same power density, the number of lamps can be doubled, and it is easier to meet the uniformity requirements when there are more lamps. At the same time, the glare quality of the small grill itself is high, and the UGR value will not increase too much due to the increase of the number of lamps.
