September 19, 2021
Opgal offers two types of OGI cameras; cooled (EyeCGas 2.0 & EyeCGas 24/7 PRO) and uncooled (EyeCGas Mini & EyeCGas 24/7). This article will help you better understand the difference between the two technologies, including the benefits and limitations of each.
What is the difference between them? The answer is not complicated; however, to understand the answer, we’ll summarize the background of this technology.
Let’s start with the electromagnetic spectrum. In a nutshell, the electromagnetic spectrum refers to the travel of a photon (a tiny particle that comprises waves of electromagnetic radiation)—for example, light or sound. In the spectrum, there is also infrared radiation, which is invisible to the naked eye. With a thermal camera, it’s possible to visualize this spectrum.
The infrared spectrum comprises SWIR (Short Wave IR), MWIR (Mid-Wave IR) and LWIR (Long Wave IR). However, only MWIR and LWIR are relevant for thermal imaging. SWIR is outside the thermal imaging spectrum and not relevant for OGI technology.
Cooled OGI cameras have a cryogenic cooler inside them, enabling the thermal camera to “see” compounds in the MWIR. The uncooled OGI cameras work without a cryogenic cooler, making them less sensitive, so we can only “see” compounds in the spectrum’s LWIR (long wave) region.
Here it’s essential to note that not all compounds have the same absorption characteristics (see the charts below) and are visible in different wavelengths.
So now that we understand the infrared spectrum a little better, let’s discuss which compounds are visible in these wavelengths.
In the MWIR, where we use the cooled OGI technology (EyeCGas 2.0 or the EyeCGas 24/7 PRO), we can detect Methane, Propane, Benzene, Toluene and over 400 VOC’s. In the chart below, you can see an example of a few compounds and their absorption characteristics.
In the LWIR, we can see compounds using an OGI camera without a need for a cooler. So, we can use uncooled OGI cameras such as EyeCGas Mini or the EyeCGas 24/7. In this area of the spectrum, we can detect higher concentrations of Methane. In addition, we can see SF6, Ammonia and HFCs as well. You can see the chart below with the absorption characteristics of these gasses.
So now that we know which compounds can be visible with each type of camera, why would you use a cooled camera when I can use an uncooled camera which is more cost-effective?
As you can see in the charts above, a cooled camera can detect many more compounds, Methane, CO2, CO and 400 VOCs, in much smaller concentrations. In comparison, the uncooled camera is limited to Methane in medium to large concentrations, Ammonia, SF6 and HFCs.
So when you’re choosing the right OGI technology, remember:
Cooled OGI cameras: These are very sensitive, more expensive than the uncooled camera with high-quality images. You can see tiny leaks of Methane, CO2, CO and over 400 VOCs from distances as far as 10 kilometers (6.2 miles) away.
Uncooled OGI cameras: These are not as sensitive, less expensive, with lower image quality compared to the cooled camera. Can detect Methane – medium to large leaks (usually from closer distances), SF6, Ammonia and HFCs.
Depending on your application and requirements, each of these technologies has its pros and cons. On the product level, there are also differences, which we can elaborate on more in detail. Since the cameras are updated frequently, you can contact us, and we will be happy to present them to you.
For more information on our Optical Gas Imaging (OGI) solutions, visit our Industrial Solutions page.
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