Btu meter

Steam for everyone to be happy

I am glad the owners are liking this idea. It seems they are also going for some improvements on their side of the zoned steam (don't forget vacuum breakers and open to the atmosphere air holes.)

I don't know what exactly you want to do with the orifice plates, unless you want to measure steam flow rather than condensate flow. For small scale applications (like this one) steam flow measurements is more complicated than necessary. Condensate metering, on the other hand is easy and near fool proof.

As far as the BTU condensate meter, this will all be very easy since you have all the submetered heat in the separate building coming back in one pumped condensate return line.

The easiest is to simply add a water meter (a special one that holds up to hot water) after the condensate transfer pump and before your boiler room return system. Such liquid condensate meters can come in temperature compensated reading - which is more accurate. The readings in gallons or in pounds can be easily converted to BTU according to a steam table and your operating pressure. All this is very inexpensive and very reliable. Add a strainer to protect the meter.

In the heat break down, tell your owners to think of how they will divide boiler maintenance cost, whether it should be split per BTU or not.

Gravity condensate meters also exist. Those you place before the transfer pump.

If you have a district system anywhere near you, look for a local meter supplier. In the most basic form, a hot water meter will do since you have a pumped return.

http://www.forbesmarshall-inc.com/Controller/SubProducts/Binaries/new_condensate_meter.pdf

http://www.epa.gov/AIRMARKET/fednox/mar99/trigen5.pdf

http://www.cadillacmeter.com/pdf/condensate.pdf

I'm not a big fan of traps on the headers to remove hot unboiled steam, separate equalizers being preferable. Is there a conflict problem with the two boiler operation feeding the common header?

Good job making this sale.

Interesting take guys. Seattle Steam meters condensate with some good success. I guess I am thinking from a different perspective (perspective of the guy who has had to do the programming i.e.here's what we designed.. now you make it work Josh). You win guys I am in ageement with you.

One thing I might ad to Brad's post though.. I would still use a differential pressure device rather than a paddle wheel (strictly from a practical sense). The paddle wheels can be a nightmare maintenance wise.

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No challenge taken! I guess with anything a proper installation and commissioning will insure longetivity ( a paddle wheel for example). A cheaper installation cost for sure. I have seen alot of them ripped out and replaced with orifice valves and delta P transmitters because of poor installation and start up.

Again I think you are thinking a little more practical installation expense wise. I am just thinking of what I have had to endure myself. I guess this is sort of an O-Ring VS. push nipple debate! More civilized though!

Take care friend... I think I am going to do something a little less "nerdy" now. We are such nerds aren't we? Typing away about BTU transmitters and instrumentation on a Sunday!

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Playing fastball and going for the Magnus effect

Well, I'm done with the nerdy outdoor stuff for now, it was beautiful outside, but too sunny and now too dark. Pretty soon it'll be too rainy and too cloudy, and I'm too whiny.

Frankie, I had a totally different picture in my mind of your system - it was what I thought I remembered from the last time. Thanks for taking the time to clear it up. Just for the record, I have nothing at all against spill over traps. I'm sorry.

Back to steamy stuff. There's never anything to complain about there...

Of the two methods, measuring the steam gas or measuring the liquid condensate, and my neutral point of view... to add to the challenge...

Just a few years back, measuring flow, in a three inch diameter pipe for instance, would cost a fortune. The mechanical turbines definitely had their limitations as far as measurements from low flow to high flow (high velocity flow occurring on low pressure start up). Electric impulse type turbines nowadays are much better and of course, they rely on wonderful electronics, and, I think, we see more turbines again.

Steam has long been measured with thin orifice plates, also with venturi jets, and with pitot tubes, and floating cone shaped plugs. All these gadgets were never cheap to buy nor to operate. The weak point of a pre-electronic age was the mechanical integrators. Add in measurements for fluctuating temperature, pressure and steam saturation point, and you were left to analyze chart planimeters by hand and perform live integrations, hourly, weekly, monthly... it wasn't easy, you needed a PhD to be a meter reader...

With such an involved procedure these methods were not highly practical, and highly subject to error in wildly erratic space heating applications and thus worthy of all of the steam customers' evil suspicions. These machines were expensive to buy, expensive to read and expensive to maintain.

Enter electronics, particularly in the very last few years, and the advent of wireless networks and these orifice devices are the easiest thing to implement. Two pressure transducers and a bunch of other sensors all plugged into some plain (again by today's standard) software and you can build your instantaneous integrator with all the complexity you wish. Easy-ish and affordable. (We use this sort of stuff on compressed air lines) Advantage Josh.

Compare all this fancy fluid flow analysis to the simple Cadillac metering drum which measures liquid condensate by the bucket. Meter reading only involves looking at a dial. It's so easily comprehensible to a property manager or a tenant or anyone else, that it is never necessary to have to pull your meter boy by the ear to get a correct reading. (Electric meters with peak demand readings already fly way above general comprehension). Advantage Brad.

Same thing with your water meter. Everyone is happy with them because they look so innocent.

That's why I think Frankie's application might be best served with a water meter (in gallons) placed after the properly throttled condensate return pump. Should the parish and the school board ever get into an argument and start pulling each other's ears over the meter readings, all you need to do is test the fancy integrator with a gallon jug - anyone can do that, plus anyone can visualize water flowing. Gasses are more mysterious. Also, without electronics, you have no reset button to fiddle with, just seemingly incorruptible mechanical hands.

But to keep up with time, I have to acknowledge electronics and gas flow meters are ever more and more interesting to look into and so is internet based data acquisition. The advances are wild, but you still need to trust them intuitively. There's still the vortex and the ultrasonic and (for liquids) the Coriolis and the magnetic. Choice.

Here is why I like condensate meters in gallons, I like metric units too, but this one here is really good - it's like magic.

Let's say we burn one therm of gas, or one CCF. A CCF is worth 100,000 BTU. We burn it with the standard combustion efficiencies of 80%. With what we've got we make steam which will condense in a radiator at, say 212F, loaded with 1150 BTU/lb. Returning from the radiator, the condensate is still hot, let's say 180F, the unused heat amounts to 148 BTU/lb. The net heat transported is thus 1150-148 = 1002 (or 1000) BTU/lb. Also reading from a table, a gallon of water at 180F weighs 8 lb. Isn't it neat how the stars are lining up?

Let's see how many gallons of condensate we'll watch floating by as we boil steam for one CCF worth of gas... no adding machine needed...

1 CCF gas * (100000 BTU / CCF gas) * 0.8 * (1 lb steam / 1000 BTU) * (1 lb condensate / 1 lb steam) * (1 gal condensate / 8 lb condensate) = 10 gal condensate.

Isn't that wild? 1 CCF of gas converts to 10 gallons of condensate. In other words, if your gallon-o-meter measures 2340 gallons, you'd better find something like 234 CCF on the gas meter (plus some allowances for blow down and steam losses, that's why feed meters are wonderful). Also, if your boiler efficiency is no longer up to it, the 0.8 coefficient changes and messes up the numbers a bit, but oh well. Match point: Christian

There, wasn't this a heap load of fun? Anyone want to play tennis with me, I don't cheat, my arbitration is completely above board and neutral... ahem. Isn't it nice how this little kid is playing all by himself?

Best regards to all ;o

CH

Why did I mention that? O-Ring guy til I die. (Just becuase I cuss quite a bit while re-building push nipple boilers.)

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