Most Efficient Torque Producer 1

[bcavender]

Given a source of clean 100-300 psig air, what device design would have the highest efficiency for extracting/delivering energy?

What is its advantage?

 

[compguy22]

what flowrate throughput is available? what is the temperature?
You may consider a combination of turbo expander and gearbox to achieve desired torque?

See

http://wrap.warwick.ac.uk/98735/7/W...air-expansion-machine-compressed--He-2018.pdf

page 16/20 for selection guideline based on specific diameters for expander.

 

[bcavender]

Temp would range 40-110F. I haven’t received flow availability yet.

The Warwick paper is exceptionally detailed.
Most excellent!!! It will take the better part of the day, but its practical nature will make it well worth the time spent.

Kudos on helping with such a spot-on assist!!!
Very big help …

Best regards,
B

 

[compguy22]

Welcome, maybe if you arrive at a selection, if you have the chance to share some info. would be nice.. so we learn from it

 

[bcavender]

CompGuy,
Will do!

The Warwick paper gave much to process and I’m still in discussion with the folks that asked my help, but I will definitely come back here with the pearls that turn up.

The PressureRatio/Flow graph for different comp types was really valuable … with a good sized rabbit hole to explore of itself. Helps the focus greatly!

eng-tips.com is top drawer!

B

 

[georgeverghese]

Isentropic efficiency is highest with pd machines - should be close to 100% (>95%)for reciprocating machines used as expansion engines, but reliability would be lower than with centrifugal type expanders. A 2stage centrifugal expander would have a higher isentropic eff than a single stage unit for the same overall pressure drop. At lower speeds, pd machines (recip, screw, sliding vane) would maintain isentropic eff, while centrifugal expanders would show even lower isentropic eff.

 

[bcavender]

George,

Thank you for your comment.

I’ve seen a number of hydraulic positive displacement motors, but I have essentially no real world experience with air motor vendors and their quality.

In my searching, I’ve seen a good swath of unfamiliar co names making pneumatic motors. Do you have any suggestions as to who has good chops and history in that space?

Thank you!!!

B

 

[georgeverghese]

All air motor drivers I've come across are close coupled to non critical utility intermittent service pumps - I've not seen them sold otherwise. Reliability is not much to brag about, but they are easy to snap into use, noisy. What do you need them for ?

Here's the Haskel air driven hydrogen compressor

https://www.haskel.com/en-au/products/gas-boosters

 

[bcavender]

A friend pulled me in on a project that needed just a tiny amount of power for some remote instrumentation. The rub came four fold in the site has a complicated layout where everything was not precisely documented, the ground is almost all bedrock, overhead lines posed other drawbacks, it’s a ‘rush’ project and his ’leaders’ downtown already froze capital projects for Q3.

SSDD.

Our sitewalk uncovered two old, but sealed pipes going all the way out to the little hut. The main station has a large compressed air supply in easy reach. So the idea popped up to put an air motor with appropriate 48vdc gen driving a battery charger in the hut with a gas solenoid valve to occasionally spin up the gen, charge the batt system to power the little RF telemetry squawker that sends a handful of data values about once a minute.

Rather than a $85k+ digging project in a long run with unfriendly stuff buried below and less friendly deadline, my friend can avoid the capital project entirely and expense a few items and have the guys in his shop fab this up in their spare time.

My initial back of the envelope thinking is that we will need ~1200 to 3600 rpm in the range of 3-10 ft-lbs to turn the crank after I can pick up a few more details. Something interesting/new to learn. I am curious to see how the numbers can work out here.

And wings/beers for the crew once we tune this up :^)

 

[georgeverghese]

Try talking to Haskel - they may have done this before.
Alternatively, for plain low power telemetry, local solar panels may do just as well to charge up the battery bank - plenty of sunshine in TN ?

 

[bcavender]

Actually solar was my first thought too, but they didn’t like the variability issues they had seen with a prior setup on some other area. (Likely too little panel, batt, too much dust, etc.) Their enviro was challenging. TN clouds up in Nov/Dec with spotty clear days until Mar/April, some years better, some worse. Most folks here love the warm summers/mild winters and there are several public/private/TVA related arrays of size. They started up daily production charts on the web, but they disappeared. I’d like to see that data. Bet there is a story there.

I think these guys were just squeezed to the max w personnel cuts that they want to drive maintenance down as much as possible by design. Lotta angles can come into what a project needs to be.

I found it better to ask/listen more than pushing any one tech (especially since I don’t sell eq).

Biggest problem usually is to figure out the right questions so what they want converges with what they actually need. :^)

 

[georgeverghese]

Coppus turbines were used on remote offshore platforms for power generation with high pressure natural gas. Think Coppus turbines has since 1990 or so has been swallowed up by Dresser Rand from what I gather on the net. D-R have their own 5-10kW steam turbines for power generation also - that may be another avenue also, since I dont see any problems with making a backpressure non condensing steam turbine work on compressed air.

 

[georgeverghese]

Solar based Stirling cycle 3kW power generator. There may be some company offering similar remote power generation kits. Maybe a pressurised washwater tank topped up every now and then can keep the dish clean in dusty environments

https://youtu.be/VEpq-WCTOrM

 

[bcavender]

Been binging on turbo machinery sites and papers.

I have not run across a 3kw Sterling machine on a commercially basis. That would be most interesting. Do you know a vender?

 

[georgeverghese]

These people are in England. There would most likely be many more similar manufacturers in the US, I would suspect.

https://www.solartronenergy.com/applications/electricity-stirling-engine-with-solar-concentrator/

http://www.stirlingenergy.com/

 

[bcavender]

Looks good!
Thank you!
B