With budgets for laboratory equipment being stretched as far as possible, the question “do I really need a cooled incubator, I’ll be running it above ambient?” is always asked.
One of the most common uses of incubators is for cultures running at 37oC. At this temperature, a standard non-refrigerated incubator is fine. The issue is with processes that require constant and exact temperatures between 20oC and 28oC.
Cooled Incubators & Refrigerated Incubators Buying Guide
Most manufactures will state that a non-refrigerated model is capable of maintaining temperatures of ambient +5oC, with the additional 5oC to take account of extra heat generated by the running of the machine. The problem is temperature stability. When running at higher temperatures, say 37oC, the internal conditions are entirely controlled by the machine; any external temperature rises can be countered immediately by the suspension of the heater. Then, the large temperature difference between the incubator chamber and external ambience means that any cooling required happens quickly. This ensures inner temperature stability through a range of external fluctuations.
When running at lower temperatures, for example 25oC in an air conditioned lab at around 20oC, any external fluctuations would push the ambient temperature to within a couple of degree of the desired internal temperature. Even when the incubator shuts all heating down, the minimal temperature difference means that no functional heat conduction will occur and there will be negligible natural cooling. Combined with residual heat from the running of the machine, the unavoidable outcome will be a rise in the internal temperature. This is why temperature stability is greatly reduced at these temperatures.
Is this a likely scenario? Yes … for a number of reasons. Air conditioning systems are designed to be as economical as possible and are built around the calculation of how much heat is generated in the room. In the usual office environment, this calculation considers the number of people and computers that will be in the room. The laboratory environment is much more difficult, especially if there is a lot of laboratory equipment in the room. A change of research goal or preproduction test may see a whole range of new equipment introduced into an existing lab. The additional heat generated by these machines may exceed the capabilities of the existing air conditioning, resulting in it having to run flat out constantly. With no reserve left in the system, there will be no temperature stability and the actual room temperature may be considerably higher than the set temperature. Any fluctuations in room temperature could not be counteracted by the air-con system.
Do You Need Advice on Which Incubator to Purchase?
What if the air-conditioning went down? It’s one of those incidents that seldom happens, but when it does, it can be an absolute disaster. With the value of some batches of samples, especially within the pharmaceutical industry, far exceeding the cost of any of the equipment in the lab, the money saved by taking the gamble on a less flexible incubator suddenly seems insignificant.
It is for these reasons that we always advise a cooled incubator where the application requires constant temperatures of less than 28oC. There are a range of manufacturers offering incubators that operate from +4oC to +65oC, but for the best combination of performance and price, the SciQuip C-Series Incubators are hard to beat.BACK
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