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Following up on Post #2925
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The input to the generator is 133 watts, if we assume 80% efficiency and 100 watts output.The conversion factor that Google found is 1 Watt = 0.00136 horsepower.
The steam engine needs to supply .18 horsepower.
.21 horse power divided by .00136 gives: 154.4 watts and change
That is well above what is needed for the little demonstration project, but it leaves plenty of room for testing beyond the initial goal.
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For SpaceNut re selection of air motor....
Fill in at least two of the three fields (torque, speed, power) to find the missing value
Torque (Nm)Speed (r/min)
Power (Kw)
The web site asks for two of three values .... can you supply those?
The speed would presumably be the speed needed by the generator.
I am trying to discover the price for one of these
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For SpaceNut ... here's an "air motor" from Amazon...
It is a pneumatic drill head that consumes 7 cfm. It costs so little I'm a bit taken aback.
https://www.amazon.com/Rockwood-Inline- … 90&sr=8-14
Brand Rockwood
Power Source Wind Powered
Voltage 110 Volts
Color Silver
Special Feature Variable Speed
About this item
The Rockwood 3/8 in. Inline Drill Is A Heavy-Duty Industrial Level Tool With Hardened Planetary Reduction Gears Ruggedly Designed For Many Years Of Reliable Service.
Slim And Compact Inline Design With Variable Speed Control
High-Torque 5-Vane Ball Bearing Air Motor
2,500 Rpm Free Speed ; Air Consumption: 7 Cfm [198 L/Min] ; Inlet Thread Size: 1/4 in. Fnpt ; Length: 8 in. ; Width: 1.5 in. ; Weight: 2 Lbs
Weight: 2 Lbs.
› See more product details
The reference to 110 volts is out of place, for a pneumatic tool.
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I wondered about efficiency of pneumatic devices, and Google found this:
Pneumatic motors are also used stationary in a wide range of industrial applications. Though overall energy efficiency of pneumatics tools is low and they require access to a compressed-air source, there are several advantages over electric tools.
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This is for SpaceNut ...
The weekend is here, and I hope it finds you in good spirits and with a bit of extra energy to invest in the forum.
I'd like to see if we can put Steve Stewart's interesting new topic back into motion. Your first attempt to help appears to have been a bit much for Steve, and we ended up with a bunch of potholes in the fabric of the archive. Please consider asking Steve how you could help.
It would be ** great ** if you could help me spec out an air motor for the Thermal Energy Battery experiment I'd like to run in parallel with the much more ambitious project of kbd512. As things stand, we know the horsepower to be delivered to a generator, but the vendor seems to want torque, and I have no idea how to determine what torque is needed to drive the generator.
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This is for Void regarding system issues ...
Best wishes for success in resolving whatever unusual circumstances you are seeing in the operation of your system.
Since you are an experienced computer user the best we (forum members) can do is to follow along as you work to find and correct whatever the problem might be.
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Steve Stewart's topic is here
The first item fails as there is no starter tank of water, natural gas source or power for the system to work as it gets clogged on fuel cycle use of natural gas due to carbon content for the fuel cell. Since the reformer needs steam to remove the carbon and that requires power also to make happen.
3 strike you are done with what is being portraid as perpetual energy storage system that has no losses, no storage, toxic plant atmospher ect....
What is there is in need of modifying as we do know the rate of natural gas required at 8 cu ft o
Converting between cubic feet of gas and liquid gallons, keeping temperature constant helps decode typical gas meter readings given in cubic feet. 1 gallon of LP gas C 3 H 8 = 4.20 lbs (at 60 degF) and contains 8.66 cu. ft. per pound 4.20 pounds x 8.66 cu. ft./pound = 36 cubic feet of gas (at 60°F) per gallon of LPG
The typical 25lb tank holds 20 lbs of fuel for use.
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For SpaceNut ... thank you for taking me up on the offer to discuss Steve's topic here. It will take anyone some time to digest the topic. It is definitely not something to be scanned and then opined about.
Steve suggests taking the topic sentence by sentence. I'm game for that.
If there is some detail Steve is missing, that would be the way to find it.
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post 2 of topic kilowatt reactor from the demonstrator to get 10Kw outs and 30K are radiated by the system to space. So, to get 30Kw electrical output the reactor will be sending 90kw of waste heat to space that at this point cannot be retrieved.
Adding in other sources such as solar that have no storage battery and no grid tie'ng system does not add to peak capability as you must also sync the ac signals to the grid tie system for the dc source that stored the energy to be able to give peak draw capability.
Stating saving an amount without any limitations that the storage device will have, is more hand waving.
Storing AC is done by converting it and even that possibility is not stated in any form or type of store that is possible.
You cannot store watts of energy directly as they are a measurement of energy voltage and currents.
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For SpaceNut re #2934
Thanks for continuing to think about Steve's topic!
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Reminder !!! While we still have a bit of weekend ahead ... I'd appreciate your help selecting an air motor to deliver rotation to the generator. I've tried to show what the vendor is offering ... a .21 horsepower motor looks good. However, they want to know torque. Can you deduce what the torque would be for the generator we've been discussing? It will deliver 9 Amps at 12 VDC into incandescent lights as a load.
What torque will deliver that performance from the generator?
They might have been asking for rpm as an alternative.
You can find the web site by looking back a post or two in Housekeeping.
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Shortly after this time Yesterday 20:58:46 I was not able to edit or make new posts here in this or any topic on NewMars as I was getting the apachee error.
I took a look at the generator but what they are showing is from https://www.rareelectrical.com/ does not appear to be a dc generator but rather a motor.
found the one which was on Amazon
it is lacking the power curve information from the websites spec pages.
Yes, some motors can be used in reverse, but they are not at the same voltage output as a generator and take more input rpm to make it function.
Torque is going to increase from its initial amount of drag on the shaft as the load increases on the generator and since these are usually run with a gas-powered motor pulley belt to most it will not matter how much that is.
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For SpaceNut re #2936
The Apache error is going to plague us until we find out how to fix it. I found a number of citations about the problem and posted the list in a topic a while back. I was hoping someone would study the list and solve the problem, but it appears the problem remains.
Regarding the web site your found ... that ** is ** definitely interesting.
It appears the site has no generators at all, as makes sense, since the generators I found is for golf carts, and the site you found is for automobiles, which haven't used generators since the 1960's (or so I'm told).
Unfortunately the post where I showed you a golf cart site is past the 25 post page marker, so I'd have to to back to a previous page to find it.
OH ho! I put this into Google: starter generator for golf cart
The result came back with many citations of "starter generator" devices for golf carts ... these (apparently) are used to start an Internal Combustion engine. and then generate 12 VDC. What I found amusing is that company you found was listed multiple times.
Pricing all seems to be in the $120-$130 range
I hope you can find a few minutes to go back to the post where I showed a web site that offers air motors.
They want to know two of three pieces of data in order to provide a price on an air motor.
Amazon found an air motor in the form of a pneumatic drill for $32 or so. The concern I have is the low efficiency of this device.
A ** real ** air motor should be more efficient, if machining tolerances are high.
I like the idea of an air motor compared to a steam engine, because the difficulty of working with hot steam is avoided.
The output of a Thermal Energy Storage batter that uses liquid air as the cold store, and hot material as the hot store, would deliver room temperature air as the output. That air would be fed into and air motor, which would drive a generator, which would light the incandescent bulbs.
By designing and building a system able to light 108 watts worth of bulbs for an hour, we would have demonstrated the practical value of kbd512's concept.
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Air is a very common shop tool, and we supply it usually 45 to 90 psi for use connected to a large reservoir of it as that is where the cfm must come from as it an open loop use as what we are trying to do is closed loop, Making use of heat and cooling in the loop to make state changes in pressure.
Your application just means less heat and cooling are required for the cfm volume and pressure to make the tool function.
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SpaceNut .... you've been busy with work, family and other activities.
Starting at this post, I've been doing some investigating of kbd512's idea.
http://newmars.com/forums/viewtopic.php … 66#p210366
Rather than repeating all that work, please review the posts. You will see the set up for the question I am asking for help on.
The vendor wants two of three variables to give a price.
http://newmars.com/forums/viewtopic.php … 66#p210366
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For SpaceNut .... I went back and found the site where specifications are requested:
https://tools.cp.com/en/products/air-motors
The selector menu wants tWO of three of: Torque, Speed (rpm), power
The power output we want from the air motor is .21 horsepower (133 watts)
RPM should be whatever is needed for the 12 VDC generator to provide 9 Amps at 12 VDC.
Can you determine what the RPM needed might be?
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I just went and searched for other topics to make use of and here is that list.
Supercritical CO2 - Useful technology?
Compressed gas energy storage.
So things we still need to have to create answered as they change everything
1 open or closed loop?
2 duration of use?
3 mobile self powered or just movable or fixed never moving?
4 heat source and sizing of capacity?
5 cooling whether active or passive with air or water or exchanger combinations
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Spacenut: logout button does not work. Had to leave and just let it time out. -- GW 6-4-2023
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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Hi SpaceNut re #2941
It's ** good ** to see all that assembled knowledge brought to bear on this problem!
Please see if there is any chance you can determine what the vendor is asking. We have a plan for a 12 VDC generator to drive some incandescent bulbs. The amperage is chosen as 9 and the voltage is given as 12. From this we know that 108 watts are to be delivered by the generator. A wide variety of suitable generators are available, as we have seen from both the web sites I found and the ones you found.
Given one of those generators and the defined load, the air motor vendor is asking how many RPM we need to deliver the stated current into the load.
We do know that the horsepower is on the order of .21. We are assuming 80% efficiency of the generator, so we are assuming the air motor must deliver 135 watts. The air motor vendor is asking for either torque or RPM. Of the two I am hoping you can estimate the required RPM.
Another way we could go is by observation (measurement). I'm hoping that there is enough theory available to be able to estimate the RPM needed to cause the generator to deliver the desired output.
In previous posts you have given a range of possible values for the RPM. I'd like a precise number to enter into the air motor vendor web site.
Do you have a friend with an old golf cart generator you could borrow for a day or so? It should be possible to set up the experiment without spending any money. It would take a bit of time.
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Already given above
12v x 1.5 A = 18 watts for each hour that you will want it to light for each bulb. so, 6 bulbs x 18 w = 108watts is correct for the circuit.
The particular alternator will produce at 600 rpm about 6 amps at best, but the voltage will drupe to less than 12 v value.
At 1500 rpm the alternator will be near 12 amp and at 2000 rpm above 20 amps while continuing to 2500 rpm to 3000 rpm for full power before getting too hot at full amperes of 25A. Also, a typical alternator is charging a battery so its normally going to be able to put out approximately 14v under lighter loads than it is spinning for.
If max load is the 9Amp then that is the 75% point of power meaning, we want to over produce by 25% to take care of voltage sag which should be near 1500 RPM of the 3 to 4 inch pulley.
If you interface that with a ration of a large pully to the small one with a belt, then the rpm of the large will drop by that ratio.
Where are the horse power and air motor wattage coming from as we do not care about either to turn the shaft of the pulley at rpm.
Those come into play for torque which is related to source air pressure for the tool to make use of.
Seems the calculator does not see values less than 1 kw thou the catalog equation shows the information.
you can actually pick a product from the catalog based on RPM and available pressure.
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Gw seem to be having a network lag for the function of log out as I had no problem doing so but have seen this on my computer for other websites and like selection buttons. I usually find duplicate programs running in the tasks manager and things that windows has turned on.
Killing those takes care of the issue.
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For SpaceNut ... re air motor ...
Thanks for the RPM estimate of 1500 ...
That was enough to get me past the first state of the air motor selection process. At that point, I learned that Chicago Pneumatic has a gigantic global distribution network.
Here is the product code that popped out:
Documentation
Product nameM84-2400-K-ATEX
Product number
2051479154
I found a company that carries 133 of Chicago Pneumatic air motors:
https://airtoolpro.com/chicago-pneumati … tion-tool/
Out of those 133 there should be one that fits the requirement.
Please keep in mind that Amazon offers a pneumatic drill for $32 and change.
An air motor needs to exceed the performance of the drill by a good margin.
OK ... I filled out the contact form and will report if and when a reply arrives.
This outfit would be wanting to sell thousands of these, I'm guessing.
As you pointed out, the selector form does not accept horsepower less than 1, so the motor would be way over sized for the initial test goal of 108 watts. However, both the motor and the 12 VDC generator could produce a lot more output if the goal post is raised.
Once the generator and the air motor are agreed upon (decided) then we can approach Calliban and kbd512 for their deliverable of compressed gas.
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Just check on the M84-2400-K-ATEX and on this website https://airtoolpro.com/air-motors/multi … eversible/ it's not cheap at $2,107.86...
The range offers non-reversible versions delivering a maximum power of 840 W (1.13 hp), with torque ranging from 0.74 to 299 Nm (0.55 to 221 ft.lbs) and speed from 45 to 20,000 rpm.
We can make use of other pneumatic tools that are less costly and modify howe to connect them for testing of design to create power on a less costly scale.
JET JAT-401, 1/4-Inch Pneumatic Die Grinder, 1/2HP (505401), Grey,black
We can even use something like this as we can set rpm and other such functions from the built in control.
Keep in mind that a pneumatic tool is not a turbine as they vent the air after use and a turbine will recirculate it.
This only proves that we can turn the shafts if we have pressure in the loop that we can make power.
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For SpaceNut re #2947
First! Thanks for your follow through on the airtoopro web site!
It was baffling to me, but somehow you figured it out!
$2,107.86 is probably about right for a machine that is going into an industrial setting for many years of ultra-reliable service.
The $32 air drill from Sears does exactly the same job, but I'm guessing it is far less efficient.
What we could try to determine next is what air flow (pressure and delivery over time) is needed by this tool.
The Sears ad for the air drill reported it needs 7 cfm delivery, and I would assume that would be at the standard of 90 psi for pneumatic tools.
Taking that as the figure to work with, it is possible for kbd512 and Calliban to design their energy storage system to deliver 7 cfm for an hour.
A point that will pop out for anyone reading this sequence, is that the power delivered by the rotary air tool is suitable for delivery directly to the drive train of a vehicle, although .21 horsepower is not too useful, but I suppose it is better than nothing.
In case our readers miss the decimal, that is about 1/5th horsepower.
Regarding turbine recirculating gas .... That is a function of the system design. Turbines don't care if the gas is recycled immediately or via the Earth recycling system. Aircraft turbine engines most definitely DO NOT recirculate the gases passing through them. The process of tapping part of generated energy to feed back through the drive shaft is NOT recirculating the gases.
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The issue will be that the storage tank needs the capacity to maintain the hour time span unlike a closed loop.
https://allaboutaircompressors.com/what … ith-chart/
https://www.vmacair.com/blog/sizing-air-receiver-tank
https://fluidairedynamics.com/pages/cfm … ressed-air
https://aircompressorworks.com/compress … pressor-2/
This means you are going to keep feeding energy into a dead-end system by venting the air after each turn of the shaft.
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For SpaceNut re #2949
Thank you for encouraging further development of this subtopic! A while ago, but not TOO long ago, I asked ChatGPT for help trying to figure out how long a pneumatic tank would power a tool. After a lot of back-and-forth, we arrived at a resolution that is reliable.
Given that we want 7 cfm to flow through our air motor for an hour, we can compute the total number of molecules that would need to be held in a tank. The tank is held at a pressure above the 90 psi where the tool operates. A critical feature of a pneumatic system is the pressure regulator, which has the ability to manage high pressure on one side, while delivering exactly 90 psi on the other.
Calculation of the size of the tank, and the pressure needed must include the volume that will hold gas at 90 psi after the supply of gas above 90 psi has ended.
Calculation begins with the count of molecules in that minute where the gas is passing through the air motor at 90 psi. Per our discussion, we appear to have settled upon 7 cubic feet of gas at 90 psi. I'd have to go back to refresh my memory of how to compute the molecular mass, but whatever the method is, it allows computation of the total volume/mass of gas that must be in the tank before the tool is turned on, above and beyond whatever base level of gas must be present.
There are two variables (as I recall) at work ... the volume of the tank, and the pressure to which the contents must be raised.
In the earlier study, I was looking at a specific commercial offering. it had a specific volume, and the system was designed to achieve a maximum pressure well over 100 psi, but at the moment I don't recall what that pressure was. By knowing the volume and the pressure, it was possible to compute the molecular mass that had to be present in the tank above the level needed to maintain 90 psi. The difference was the amount available to power the tool. My recollection is that the tool ended up able to run for a minimum of 15 minutes, which was sufficient for the application I had in mind.
In this case, we have flexibility in sizing the tank, and in setting the pressure before we start a run. Based upon the requirements for the test, we can compute the mass of molecules to be delivered, and then we can experiment with pressure and volume of the supply tank to arrive at a combination that makes sense.
Likewise, kbd512 and Calliban will need to deliver that exact same number of molecules, spread over an hour at a steady flow of 7 cfm.
How they design their system remains to be seen, but whatever they come up with is sure to be interesting and possibly even thought provoking.
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