PPF, photograph and Comparison of illuminants
The new technology of our LED lights Hydro Prime operates according to a different principle than the conventional light sources.
In the case of measurements of different LED grow luminaires for use in nurseries, misunderstandings may occur. The artificial light sources are usually indicated in PPF (μmol m-2 s-1). On a sunny day outdoors one measures approx. 100 000 lux, this corresponds to about 2000 (μmol m-2 s-1). The sun creates a point light. Producing this light intensity with artificial light is unrealistic for cost reasons.
In the indoor area it is possible to achieve equal or even higher yields by means of LED hydro prime luminaires.
On cloudy days the Lux values are about 10 000 to 15 000, so they are about 8 times lower than on sunny days. However, the energy conversion of the light rays through photosynthesis is not 8 times smaller. The plants also use the diffuse light to generate energy.
A point source is a direct light and causes shadows. From the plant’s point of view, only the uppermost leaves receive direct light and cast shadows on the lower leaves. However, as nature also transforms diffuse light into energy by means of photosynthesis, the plants can take up a much larger proportion relatively. This light is always present, but the natural daylight outdoors varies greatly.
Artificially diffused light is created when many light points are distributed over a certain area. Many light points produce less shadows and the whole surface is irradiated uniformly homogeneously. Thus photosynthesis works optimally. In addition, the plants are healthier and their structure is more compact.
To avoid misunderstandings, it is important to compare the radiation PPF (μmol m-2 s-1) and the definition of the cone of light.
With a standard LED without a lens, the cone of light is 120 °. An additional 90 ° LED lens on a 120 ° led in the center of the cone of Light produces a 3 times higher measurable value lux/PPF (μmol m-2 s-1). A 60 ° lens, on the other hand, produces a lux/PPF (μmol m-2 s-1) up to 8.5 times higher. The measurements are in most cases fixed to the center of the light cone by means of vertical sensors. These measurements can never show an image on the entire surface. In order to obtain meaningful measurements, it is necessary to specify additional horizontal sensors. In effect, this means that most users are disappointed by these LED lights in practical operation and revert to the high-pressure gas discharge lamps.