Eco-friendly rotary evaporation is possible and here is the evidence

If you are somewhat skeptical about the eco-friendly claims on lab equipment, well I am on your team. But it would be very nice if the rotary evaporator, as one of the most heavily used instruments in the chemistry lab, was actually “green”. Here, I review and experiment with several eco-friendly features of a modern rotary evaporator. And I was stunned to see that you can save up to 45% of energy if you apply them in combination. Read on and see for yourself.

I was having virtual coffee with my neighbors when we got into an interesting discussion on eco-friendly homes. They were very passionate about the idea of converting their older property into an “eco-house”. This would mean introducing solar panels, geothermal heating, triple-glazed windows, rainwater harvesting and so on.

I, myself, have already implemented eco-friendly solutions like good insulation and composting in my own house. I also care about household appliances and their eco-modes. But do I also have the same standards for my workplace?

Certainly when I am looking at lab equipment, statements about influence on the environment grab my attention. But I am often left skeptical about how “green” instruments and their eco modes really are.

It would be great if the rotary evaporator, the undisputed workhorse in any chemistry laboratory, is “green” indeed. But for me to really believe the instrument is environmentally friendly, I would need to see some solid scientific evidence, rather than just marketing claims.

For one, instruments emit substantial amounts of greenhouse gases, which vary according to the type of equipment they are. Some emit the most during manufacture, some during distribution, some during disposal. Where does the rotary evaporator fit?

Detailed life cycle assessment of a laboratory evaporator shows evaporators are use-intensive products when it comes to greenhouse gas emissions:

rotary evaporator, rotavapor, distillation, greenhouse emissions, energy

Hence, the best way to reduce the environmental impact of the rotary evaporator would be to improve the energy efficiency of the unit during use phase. This is especially true for average and intensive use of the machine.

Now comes the more challenging part. How do you go about reducing energy consumption and making your rotary evaporation more eco-friendly?

Well, looking at a modern Rotavapor, there are several features that could help with saving energy:

Interface rather than manual control of the pump
Reducing the heating bath size from 5L to 1L if possible
Using swimming balls in the heating bath regardless of size
Using Eco Mode for heating bath and chiller

As, I said, these suggestions look fantastic on paper. But are they truly efficient? Well, we set out to test them one by one and in combination.

We used the Rotavapor® R-300, heating bath, chiller, vacuum pump and 1 L receiving and evaporating flask, together with an interface for automatic control. Each experiment lasted 9 hours and consisted of three distillations of 500 mL water for 1 hour each.

In the first case, we saved 0.26 kWh of energy when the interface controlled the vacuum pump than when the vacuum pump was operated manually. We saved 0.3 kWh of energy when using swimming balls in a 5L heating bath. We consumed 0.5 kWh less energy when using a 1L bath, rather than a 5L bath.

The Eco Mode on the instrument helped save 0.26 kWh of energy when the 5 L heating bath was used and 2.5 kWh of energy when the recirculating chiller was also used.

In summary, the biggest energy savings were seen when we used Eco mode in combination with the chiller and when we switched from a 5L to a 1L heating bath.

A combined effect of smaller bath, swimming balls and use of eco mode sums up to approximately 3.4 kWh of energy per single Rotavapor® in a day.

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And you should consider the additional benefits of using smaller heating baths in combination with swimming balls. For one, there is also reduced water consumption, due to minimized evaporation into the air. There is less cleaning needed and splashing of the heating medium is reduced. The time it takes to heat up the bath is also reduced.

Hence, by using the above energy saving methods, you can save up to 45% of energy costs, bring yourself some additional benefits and be a proud user of an eco-friendly rotary evaporator.

I don’t only care about being eco-friendly during rotary evaporation. I’ve already written about the importance of performing green chromatography as well . If you are interested in this topic as well, make sure you also check out the Pure Tips booklet on safe chromatography.

How are you liking having rotary evaporation as a topic on the blog? Leave a comment below. I am always happy to hear from you.

Till next time,