Results 51 to 100 of 210
Thread: Carters Widget Revealed!
-
22-08-2011, 01:36 AM #51
-
22-08-2011, 01:40 AM #52
Re: Carters Widget Revealed!
Evening Mike
No, Just I have been hanging onto MF's every last word for days now
If I am following this part correctly, you need to wait for the system to settle (balance out/equalibrium) to achieve maximum gains in efficiency/flow rates & a constantly changing load(evaporater), de-stabilises the performance of the widget, hence further research & developent is required to fine tune performance. ???If the World did not Suck, We would all fall off !
-
22-08-2011, 01:42 AM #53
Re: Carters Widget Revealed!
This is a great suspense novel. Too bad i'm a 32 bit guy in a 64 bit world.
-
22-08-2011, 01:46 AM #54
Re: Carters Widget Revealed!
We used to install one pipe heating systems with a venturi on the return up to the mains pipe. There was a good amount of suction on the branch but the flow rate before the first tee equalled tthat after the second tee (venturi). It was an equalized loop (pressure)
-
22-08-2011, 01:47 AM #55
Re: Carters Widget Revealed!
I am no specalist in venturi or the like ( i know nothing about them) only possible application. The question then comes down to what would the actual properties be of the outlet of the widget (The inlet to the compressor), When we move away from perfect design (which as we all know happens on every system) what then would be the effects on the system.
there are other possible beneifts as well. (or maybe)
-
22-08-2011, 01:47 AM #56
Re: Carters Widget Revealed!
Similar to how the oil is returned from the evaporator in a flooded phe system, high pressure vapour is driven down a pipe that is connected to the oil pipe and as it flows it pulls the oil into the vapour and the mixed vapour/oil then returns to the compressor/or oil reservoir
???If the World did not Suck, We would all fall off !
-
22-08-2011, 01:47 AM #57
Re: Carters Widget Revealed!
Sorry to cut in Terry, go on.
-
22-08-2011, 01:52 AM #58
-
22-08-2011, 01:53 AM #59
-
22-08-2011, 01:55 AM #60
Re: Carters Widget Revealed!
There must be a flaw in my methodology. Surely others must have looked at this simple system!
-
22-08-2011, 01:55 AM #61
Re: Carters Widget Revealed!
If the World did not Suck, We would all fall off !
-
22-08-2011, 01:58 AM #62
-
22-08-2011, 01:59 AM #63
Re: Carters Widget Revealed!
Hi MF.
watching with interest. Industrial techs should pick it straight away, but I won't comment.
After our last meeting, how did things pan out
magoo
-
22-08-2011, 02:02 AM #64
Re: Carters Widget Revealed!
Since we are talking about high quality vapour and using that vapour to drive the venturi, and the suction or branch on the venturi will be at lower pressure, I am failing to see where the supply of vapour will come from to feed that branch (and therefore increase mass flow through the comp) IF you dont have a flash tank somewhere. Am I right is assuming that which will bypass the evap reduces the net refrig effect? I see some bypassing but don't know if the increased efficiency of the comp makes up for the loss in the evap.
Now my head is on the block
-
22-08-2011, 02:04 AM #65
Re: Carters Widget Revealed!
By the time I get one response in you guys are five ahead
-
22-08-2011, 02:06 AM #66
-
22-08-2011, 02:08 AM #67
Re: Carters Widget Revealed!
The idea is that the widget was to be quite simple (hence cheap) but yes could quite easily control with a sol valve and could also be made with proportinal control to keep optomised. (but we but the cart before the horse)
The very basic idea was the vessel was maintained at a constant pressure. (this makes sizeing the evap and expansion device easy) This gives us the oppotunity to allow the head pressure to fall, a lot lower that is presently classed as standard. ( so looking at the very big picture with lower head, we would get less flash gas, so the widget would not work as well, but we still maintain very high efficiency and system equalibrium) All the components could be produced as a single item, so installation would be very very similar to installing a suction accumulator with an internal liquid line heat exchanger. (Maybe with a removable nozzle orifice for different size systems, in a similar way we change the orifice size in an expansion valve)
I have but much thought and energy into this.
-
22-08-2011, 02:09 AM #68
-
22-08-2011, 02:11 AM #69
Re: Carters Widget Revealed!
Would it be similar to this?
http://www.denso-europe.com/Ejector-...000000001.aspx
-
22-08-2011, 02:14 AM #70
Re: Carters Widget Revealed!
You need to read from the start (there is reason behind my madness, in the way i started the thread) Yes there is a flash tank, or I called a vessel.
It is at pressure in the middle between normal evap pressure and cond pressure.
It is positioned in the liquid line between the cond outlet anf the TEV (expansion device) inlet.
The flash gas in the vessel is something that would normally occur just after the expansion valve prior to evap inlet, and has in energy terms very little benefit to the refrigeration system. how ever we do have to pump it around the whole system.
-
22-08-2011, 02:21 AM #71
-
22-08-2011, 02:24 AM #72
-
22-08-2011, 02:26 AM #73
Re: Carters Widget Revealed!
I understand that it is not desireable to have flash prior to the evap so i can see removing it before the TEV so am I to understand that the amount that would be moved through the device is only that amount that would normally flash prematurely and not try to get more than usual?
again head on chopping block
-
22-08-2011, 02:26 AM #74
Re: Carters Widget Revealed!
MF
I should have been more clear, I was agreeing, (with my limited understanding being) that the compressor has limited duty, and the more we take from the widget, the less can be taken from the evap/suction line ???
And my previous post ( if again I understand) if we start pulling vapour prior to a clear feed of liquid from the condensor, then would vapour be pulled through the condensor preventing/lowering the amount of refrigerant that is condensed ???If the World did not Suck, We would all fall off !
-
22-08-2011, 02:30 AM #75
Re: Carters Widget Revealed!
Perhaps a compounded cycle with inter-cooler.
magoo
-
22-08-2011, 02:43 AM #76
-
22-08-2011, 02:52 AM #77
Re: Carters Widget Revealed!
Mike first, yes we only take part of what would normally be produced in standard system. And practically has very little use (my first question) but in a normal system still has to be 100% transported around the whole system "energy in"
CM
The vapour leaving the widget (including the ejector) is combined with the flow from the evap. The vapour can only flow if there is sufficient flash gas coming from the condensor liquid, If for example the liquid was very highly sub cooled prior to the widget, then no flash would be produced in the vessel and very little flow would occur through the ejector. (the ejector has avery small hole, need good pressure to flow)
-
22-08-2011, 02:55 AM #78
-
22-08-2011, 02:56 AM #79
Re: Carters Widget Revealed!
Hi Chillerman,
the low stage piston/s suck from a low load and discharge into a vessel [ intercooler ] that condenses partiallly, the resultant vapour becomes the suction of the high stage pistons, which discharges to final condenser, the partial liquid formed in intercooler is regengerated to supply low load topped from high stage liquid. [ jet valve area ]
A short cycle description, you have two levels of evaporation and two levels of condensing. easy with screws / piston ratios with recips.
magoo
-
22-08-2011, 03:01 AM #80
-
22-08-2011, 03:04 AM #81
-
22-08-2011, 03:09 AM #82
Re: Carters Widget Revealed!
Hi MF.
very good and very clever, as in direct injection sub-cooling, a bit of a hand grenade with a loose pin though. But then again with stable loads would be very manageable in hindsight.
What happened with Mr T and Pete etc., after last conversation, good or hopeless.
magoo
-
22-08-2011, 03:19 AM #83
Re: Carters Widget Revealed!
Hi again MF.
out of interest, are you using split circuit PHEs or other HXs.
magoo
-
22-08-2011, 03:25 AM #84
-
22-08-2011, 03:28 AM #85
-
22-08-2011, 08:34 AM #86
Re: Carters Widget Revealed!
O.k. Mad. At the risk of a crash and burn probablity, there is another thought i have. Can there be a free energy effect,( minus mechanical losses) where one could use discharge pressure, or more likely liquid, while compressor is running to power a small turbine. My thought is.. the slave turbine in the suction line can increase suction pressure to compressor at the added benefit of reducing evaporator pressure, thus increasing evaporator efficiency? Seals will be a problem and so will driveshaft configuration. Increased pressure to compressor gives better efficiency on the low temp applications. So.. what do you say? Has this been debated before?.. Mike,( not the one sipping beverages on the beach ).
To the optimist, the glass is half full. To the pessimist, the glass is half empty.
-
22-08-2011, 08:50 AM #87
Re: Carters Widget Revealed!
There is no crash or burn on this thread, (not on my watch)
The discharge pressure has to be produced by power, (how ever some have looked at using ejectors to produce higher than motive pressures, but this is beyond my what I know)
using liquid soley as a driver (very little benefit) this watt a low wattage pump can pump L/S versurs head.
using the liquid then expanding through a turbine may work (energy purpose only), very similar to gary's attachment.
A lot of work has been done on efficiency and using ejectors, but I "believe" using the widget method is original and somewhat more practical (I not attepting to get 100% better performance 100% of the time)
good thoughts.
Even though you have a concept you still need to prove possible performance. I have my method, which may be right or wrong, but I am wanting others appraoch to see if it could be a goer.
-
22-08-2011, 09:41 AM #88
-
22-08-2011, 09:51 AM #89
-
22-08-2011, 10:01 AM #90
Re: Carters Widget Revealed!
If you split the flows as follows:
1. Vapour only (your 'flash gas') at m'fg;
2. Liquid only at m'l...
3. m'r = m'l + m'fg (total flow before split)
... then, if we know the pressure of each stream, we can locate the individual state points as follows:
1. Vapour - assume saturated vapour - located on right of bell;
2. Liquid - assume saturated liquid - located on left of bell.
If the fluids are mixed, then the mixture properties are constructed based on 'x', the vapour percentage in the mixture.
If the vapour is transported away, then only m'l goes towards the evaporator. The net refrigeration effect (assuming fully saturated liquid) is:
Q'evap = m'l*hfg
Where :
Q'evap = evaporator capacity [W]
m'l = liquid mass flowrate [kg/s]
hfg = latent heat of vapouraziation [J/kg]
So, the real amount of duty [W] managed by the evaporator will depend on how much liquid is actually going to it.Last edited by desA; 22-08-2011 at 10:23 AM.
Engineering Specialist - Cuprobraze, Nocolok, CD Technology
Rarefied Technologies ( SE Asia )
-
22-08-2011, 10:05 AM #91
Re: Carters Widget Revealed!
See that this thread was very busy during the night and noticed also it has been filled up to nearly 5 pages.Will make some time this evening to read was said.
It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.
-
22-08-2011, 11:54 AM #92
Re: Carters Widget Revealed!
Sir, the beach is not for me but the sailboat is and of course, so is the beverage sipping.
MF, Without a lot of pondering, I would think the venturi part of the widget will need to be on the suction line as the "motive force" would best come from higher velocity gas from the evap. There needs to be a certain differential to make the venturi work, typically 5:1 to 10:1 and there is an increased head loss incurring when the "motive force" or the straight line flow is restricted to create the suction through the branch.
-
22-08-2011, 12:02 PM #93
Re: Carters Widget Revealed!
(one could use discharge pressure, or more likely liquid, while compressor is running to power a small turbine. My thought is.. the slave turbine in the suction line can increase suction pressure to compressor at the added benefit of reducing evaporator pressure, thus increasing evaporator efficiency? Seals will be a problem and so will driveshaft configuration. Increased pressure to compressor gives better efficiency on the low temp applications. So.. what do you say? Has this been debated before?.. Mike)
There are very low wattage circulators that are magnetically coupled so the seal issue is not a problem. Of course, they are typically in the range of 1-3L/m LIQUID flow and have head values of around 1-2m. I don't know if this helps with mikes pondering. Messed up the quotes above.
-
22-08-2011, 12:13 PM #94
Re: Carters Widget Revealed!
It is not really a venturi,( I think), more like an air mover "condell" (or maybe not).
There is difference in the pressure.
This where true expertise in this field is required. ( and it aint me!)
Also you already have flow regime in the suction line (verses a dead head/static flow on say a normal venturi)
If you look on your copeland compressor program, pick R404a, pick a low evap temp and mid range cond temp, check duty,( note pressures) now just up the evap temp a bit and see what the new duty is, check the pressure difference. (you will be suprised) maybe
-
22-08-2011, 12:19 PM #95
Re: Carters Widget Revealed!
Yeh, missed the velocity factor during my pondering .
To the optimist, the glass is half full. To the pessimist, the glass is half empty.
-
22-08-2011, 02:43 PM #96
Re: Carters Widget Revealed!
I'm not an expert in venturi effect, but I have 2 concerns about this widget.
1. To create venturi, we need significant pressure difference between pressure in this vessel and suction pressure. This pressure difference will not be significant.
2. In verturi, main flow will suck secondary flow. As far as I know, main flow should be significantly greater than secondary flow. For example 10:1. Assume that flash gas is 20% of total gas flow. 80% of gas create by net refrigeration effect. It means that that 1 part of main flow will suck 4 parts of secondary flow. This will not happen.
-
22-08-2011, 03:02 PM #97
Re: Carters Widget Revealed!
A thought:
1. Replace TXV with small rotational device;
2. Liquid flashes across rotational device (RD1) to desired LP;
3. Rotational device (RD1) drives a rotational device (RD2) placed in suction line.
4. RD2 'stuffs' flow into compressor.Engineering Specialist - Cuprobraze, Nocolok, CD Technology
Rarefied Technologies ( SE Asia )
-
22-08-2011, 04:14 PM #98
Re: Carters Widget Revealed!
I tend to agree with this assessment. In the Denco configuration, the full flow of the system is harnessed to provide the motive force. As i understand it, the Carter configuration attempts to use a small fraction of the flow for it's motive force... or possibly I misunderstand the workings of the Carter Widget. I'm thinking a flow diagram might be helpful.
Last edited by Gary; 22-08-2011 at 05:16 PM.
-
22-08-2011, 05:38 PM #99
Re: Carters Widget Revealed!
Gary.
I agree that Denco configuration has greater pressure difference. However, volume of main flow is not greater than volume of secondary flow, because main flow has mixture of liquid and vapor and secondary flow has only vapor. I'm not sure that Denco configuration will work either.
-
22-08-2011, 06:35 PM #100
Re: Carters Widget Revealed!
By definition, the secondary flow is going to be a fraction of primary flow... the difference will come from flashing in the separator. The question is not will it work, but rather how well will it work?