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Suppose I wanted to continuously supply up to 15 litres of air per second, compressed to 10 bar - what would be the most efficient type of compressor, i.e. the type requiring the least energy input in order to get the job done, if we assume the compressor would be within fairly reasonable bounds of compactness, weight, cost and reliability? Let's say it:

  • weighs less than 75kg,
  • fits in a suitcase
  • costs less than £7,500 in 2021 money (note I'm not shopping. The £ figure is included purely as a universally interpretable measure of the engineered complexity of the compressor),
  • is capable of 4,000 hours mtbf, with minor maintenance every 400 hours, and
  • assume the motor/power to drive it, and cooling, are already provided and external to the weight, cost etc.

I'm unaware of how the different properties of rotary vane, rotary screw, reciprocating, axial and centrifugal compressors would affect their performance in such a role. I want to optimise for efficiency, i.e. minimise the energy input required.

samerivertwice
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  • Welcome to *Engineering* samerivertwice, but I'm afraid that *[shopping questions](http://blog.stackoverflow.com/2010/11/qa-is-hard-lets-go-shopping/)* really aren't a good fit for a stack exchange site. We prefer *[practical, answerable questions based on actual problems that you face](https://engineering.stackexchange.com/help/dont-ask)*. Take a look at [ask] and [about] for more information on how stack exchange works. – Chuck Jul 02 '21 at 15:50
  • @Chuck this is an engineering question requiring the expertise of an specialist in air compression. Most general engineers wouldn't be in a position to answer it. The inclusion of a £ symbol doesn't indicate that I'm shopping - I'm not. I included it to give a convenient and universally interpretable ceiling on the engineered complexity of the compressor. – samerivertwice Jul 06 '21 at 10:39
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    You have a list of specifications that you want your product to meet. If your question were strictly about what's the most efficient air compressor then you could just ask that and leave all the other qualifiers out. You're not, though. The easiest thing to do to answer your question would be to just Google your specifications and find the thing that consumed the least amount of power, but even then you need more detail to go find compatible units online. – Chuck Jul 06 '21 at 11:05
  • Consider where the waste is. anything reciprocating must be stopped and started - if you could wait for it to naturally stop from the compressed air, it would only work for a very specific conditions of intake air. In addition you get waste at the check valves. For rotary types, a lot of the losses have to do with flow back through the gap between moving rotor and the stationary shroud/stator. – Abel Jul 06 '21 at 13:05
  • @Chuck you call it a product but I'm not buying it, I'm manufacturing it. – samerivertwice Jul 06 '21 at 14:09
  • @Abel thanks for your help. tbh I suspect a turbine design is the optimal solution or even a turbine first stage with a reciprocating piston taking it to full pressure but the parts I don't know are how each type of loss varies with respect to pressure. What you say would favour the rotary solution since the loss I need to minimise most is heat production - escaping air would have an advantage in that regard versus friction. – samerivertwice Jul 06 '21 at 14:17
  • multiple stages can add efficiency- lower pressure deltas across a stage also means less of that backwards wasted flow. do be aware though that it could be like picking a doctor to pick a diagnosis in this area - I am biased. Someone with experience designing bellows for reciprocating compressors might balance it out a bit. – Abel Jul 06 '21 at 14:30
  • @samrivertwice - how are you manufacturing it if you don't know how to design it? Process still stands, though - find the existing product that meets your specs, then make one of those. – Chuck Jul 06 '21 at 16:00
  • @Chuck by first learning how to design it. – samerivertwice Jul 08 '21 at 07:27

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