Mastering the art of control panel thermal optimization
Credit to Author: Josep Lopez| Date: Tue, 02 Jul 2019 18:04:46 +0000
In a control panel project, you want the best possible operating and capital expenses (OPEX and CAPEX). But there are many variables in play when trying to improve OPEX and CAPEX. How, then, is a panel designer, specifier or builder supposed to come up with the best solution?
Thermal optimization software can help. And it can save money.
To understand why software is needed, consider some control panel thermal variables:
- Is the project inside a climate-controlled building or outside and subject to weather?
- What’s the humidity?
- How much sunshine is the enclosure exposed to?
- What’s the altitude, air quality, and so on?
Any of these can impact the temperature inside an enclosure and can change significantly over time.
Thermal management software can calculate the effect of these variables, allowing panel designers can see their result on delta T (desired temperature – outside temperature). Panel designers can then use the software to discover more efficient solutions, like better ventilation to reduce the need for active cooling.
Beyond ventilation, software can help evaluate and take advantage of other passive cooling. That becomes clear after looking at two different scenarios.
If the outside temperature is favorable, for example, Increasing the surface area of the cabinet reduces the cooling power needed.
Case 1:
Suppose the outside temperature is mild, around 20ºC (68ºF). Suppose that we also need to extract around 3000W from a panel enclosure, with this heat coming from variable speed drives or other high dissipation equipment such as solid-state relays.
In this situation, the right enclosure produces energy savings of up to 50%, by, for instance, going from a single cabinet measuring 2000x1000x800 cm to a configuration with 3 cabinets of the same total volume. The power of convection always plays in our favor when the outside temperatures are relatively low.
But what if that’s not true?
Case 2:
Suppose we had the opposite situation, with high external temperatures of greater than 40ºC (140ºF), which is very common in metal-working factories or metal-casting foundries. Here, the passive energy saving will come if we reduce the surface area of the cabinet or thermally isolate it. Then we can reach energy savings similar to that possible by convection.
Keep in mind that when seeking to thermally optimize an enclosure, these are the areas that software can help evaluate.
- The installation location and position of the cabinet. Suppose the outside temperature is low, around 20ºC. If so, putting the enclosure in the right spot allows us to gain 300W of passive cooling. In the two cases above, that is 10% of the total needed.
- The cooling load. That can be advantageous when it comes to refrigeration equipment. Below about 2000 watts (2 kW) load, cooling compressors are single phase. Above, they are three-phase. If an enclosure is at the 2-kW dividing line, it may make sense to study the equipment being installed to see what can be gained in terms of cooling requirements and refrigeration equipment.
- The distribution of the ventilation equipment in the enclosures. Thermal loads are not always balanced in cabinets. Sometimes it is necessary to distribute the cooling equipment according to the heat distribution or the number of existing cabinets. In this way the whole system with be more thermally uniform.
- How compacting the cabinet will impact thermal effects. Often, when trying to optimize enclosure dimensions the tendency is to compact the equipment as much as possible. But that may work against thermal considerations and lead to unexpected increases in temperature.
This type of planning and the associated calculations can be challenging, particularly when installing many enclosures. Having accurate thermal calculation software helps optimize everything and the data results can form the basis for a good starting point.
Luckily, there have been continued improvements in thermal management software and the programs are easier to use and more powerful.
For instance, Schneider Electric recently launched their new thermal calculation software ProClima version 8.0. This allows more advanced functions of thermal optimization. It also makes it possible to better take advantage of passive cooling options, such as those mentioned previously. In turn, that will lead to better CAPEX and OPEX for electrical control panel projects.
To get and try out this free ProClima software for yourself and your projects, click here.
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