Methods and Challenges
The development of lighting technologies, especially the popularity of LED diodes, has brought significant changes in how we measure and understand the power of lighting. Traditional bulbs, rated mainly by the power they consume expressed in watts (W), are giving way to more efficient and economical LED diodes. But how can we compare the luminous power of these two types of light sources?
Below is a discussion of the measurement methodology and conversion factors that allow for such comparisons.
Luminous power vs. energy consumption
Fundamentally, the luminous power of LED diodes is determined by the luminous flux, measured in lumens (lm), which is a measure of the total amount of light emitted by the source. In contrast, traditional bulbs are classified based on the electrical power they consume, not directly on the amount of light emitted. Therefore, a direct conversion of lumens to watts is not possible without additional assumptions.
Measurement methodology
Although measuring in lux (lx), which takes into account the light intensity on a specific surface, may seem more precise, differences in beam angles between LEDs and traditional bulbs complicate direct comparison. For this reason, the reference conversion is based on an estimated equivalence: it is assumed that 1W of LED power corresponds to approximately 10W of traditional bulb power. However, it is important to note that this is a simplification that can vary depending on the light color, beam angle, or type of diode.
Let's assume we have a 10W LED diode that emits a luminous flux of about 800 lumens (lm). We want to compare its brightness to a traditional incandescent bulb.
Traditional incandescent bulbs have about 14-15 lumens per watt (lm/W). This means that a 10W bulb would generate a luminous flux of around 140-150 lm. In the case of an LED that emits 800 lm at a power of 10W, the luminous efficiency is significantly higher.
To achieve comparable brightness (about 800 lm) using a traditional incandescent bulb, we would need a bulb of significantly higher power. Assuming an average efficiency of a traditional bulb at 15 lm/W, we need a bulb with the power:
Required power = (Luminous flux (800 lm)) / (Luminous efficiency (15 lm/W)) = 800 / 15 ≈ 53W
This means that a 10W LED diode with a brightness of 800 lm provides as much light as a traditional incandescent bulb of about 53W. This example shows how much more energy-efficient LEDs are compared to traditional light sources.
Impact of color and beam angle
Kolor światła i kąt, pod którym jest emitowane, mają istotny wpływ na postrzeganą jasność i efektywność świetlną. Na przykład, diody emitujące światło ciepłe białe i zimne białe mogą mieć różne „efektywności” w przeliczeniu na tradycyjne żarówki, przy czym białe zimne mogą wydawać się jaśniejsze przy tej samej mocy elektrycznej. Co więcej, diody emitujące światło o określonych kolorach, takich jak niebieski, mogą oferować niższy strumień świetlny (lm), ale ich użyteczność w pewnych zastosowaniach pozostaje niezmniejszona.
Practical implications
For consumers and lighting designers, it is crucial to understand that comparing the luminous power of LED diodes and traditional bulbs requires more than a simple conversion factor. Not only the amount of light emitted by the source is important but also the way this light is dispersed in space, as well as the color of the light, which affects perception and atmosphere.
Conclusions
When choosing between different types of light sources, it is important to remember the differences in how their power is defined. Converting the luminous power of LED diodes to traditional bulbs provides a general idea of their relative efficiency, but it is essential to consider all light parameters, including luminous flux, beam angle, and color. Understanding these aspects allows for an informed choice of lighting that best meets user needs while promoting energy efficiency and optimal light use.
