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BTU Meter (18 Posts)
BTU MeterI'm looking for a affordable BTU meter to separate 5 zones of hydronic heat in an apartment building that fed by one boiler.
You might find onebut I'll bet it would be a little pricey. Wouldn't it be simpler to put a run time meter -- they're absurdly cheap -- on each pump or zone valve, to record the time when the zone was calling? It might not be quite as accurate (and I suppose if one of your tenants is a lawyer they might get torqued) but it certainly should do the job.Jamie
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.
Hoffman Equipped System (all original except boiler), Weil-McClain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
Runtime meterNot only are they absurdly cheap, but also surprisingly accurate. You are going to be able to calculate the percentage of total fuel use required for a single zone. If zone one has used 10 hours of pumping, zone 2 also 10 hours, and zone 3 15 hours, then 1, and 2 will have used 2/7 each, and zone 3, 3/7 of the total cost of fuel used. It could be seen from this example that zone 3 was cold-blooded, and had set the thermostat higher than the others.
The drawback to this system is the need to read the meters on the same day as the main meter is read.
If a lawyer can argue against this method, it would only be as a result of proving that the system has been badly maintained, and therefore has inequalities in the hot water distribution.--NBC
run time meterAny suggestions on a brand of run time meter that I should be looking at?
Hour meterThe problem with using an hour meter is it only shows the time that a thermostat is on. It doesn't show IF the zone valve is open or IF the boiler is running. Also it doesn't measure water flow. so if one zone is 3/4 inch and runs 10 hours it will flow a lot more BTU's than 10 hours of a 1/2 inch zone. Also if one loop is longer than the other it will flow less.
just ran into precisely this problem today . . .hour meters on zones that have radically different amounts of radiation don't tell you anything about relative consumption of fuel being divided up, unless a highly educated correction is made based on radiation per zone is made. And tell the tenant who is going to have to pay more than their proportion of hours suggest because they have more radiation and they will suddenly become ignorant of heat transfer science -- if they ever knew anything about it.
And even then, you can still have significant discrepencies if flow rate varies given head pressure including piping and gravity resistance, air in loops, etc.
supposedly iWorx from TACO does this but i don't know where that is really going. don't see components for sale anywhere. maybe they are so specialized you don't find them on the net the way you do TACO's other offerings, but I notice one iWorx component that was listed on pexsupply.com has been discontinued.
found some non-TACO btu meters that appear to be in the $750 to $1000 range. That is a little pricey, i could maybe see under $500. And there is the problem, as others have pointed out, that when some tenant wants to lawyer up, the sods down at your local public utilities regulators frown on these arrangements. which is stupid of course, because, even if they are imperfect or meters are not utility grade, without an ability to make an approximation of splitting the utility bill, inhabitants have no incentive to conserve as the only alternative is to charge as a percentage of the building area regardless of whether they set their thermostats low or high.
With the advent of smaller modulating boilers this problem may evenutally go away as this hour meter type energy split is common in many condo conversions from the 80s when there weren't boilers available with low enough firing rate to not be overfired for individual apartments. Of course the expense of boiler replacements is more than anyone has in mind when they go to get the metering as fair as possible, but before i'd spend in the thousands on a meter for each apartment i'd consider putting the money toward separate boilers.
That said, if anyone has had good experience with a btu meter and estimates that one can be bought and installed more like $500This post was edited by an admin on December 2, 2013 2:07 AM.
lets consider an oblong boxit has an apartment at each end and 3 in the middle .
the two end apartments have three walls to the exterior or "To the Weather"
the other three see the inside walls of the adjacent apartments ...
no doubt this inspired Edward Allen Poe to write this story ...
the boiler of Amontillado?if i don't laugh about this, i'll cry, so thanks
BTU metersCheck out http://www.badgermeter.com/Industrial/Impeller-Products/Sensors/380-Series-Btu-System.htm for small BTU meters. http://www.veris.com/Category/Flow/Impeller-spcMeters/Tee-spcMeter,-spcSystem-spcBTU.aspx has pricing.
nicethat badger is the meter i was looking at as an alternative but this is $200 cheaper than i was finding.
This isthe perfect place for Delta T pumping as part of the arrangement . All you need is to know the GPM . No lawyer can argue against A proven equation
Apt #1 225 Gallons = 2,250,000 BTU / 10000 or the dreaded 22.5 THERMS . No argument can be made at that point . Run time can present a problem . This type of system can be hooked right up to a BMS so the utility can generate the bills for each tenant to avoid further hassle . How do they currently produce DHW ?You didn't get what you didn't pay for and it will never be what you thought it wouldThis post was edited by an admin on December 2, 2013 10:24 PM.
There can be other minor technicalities ,i know many of them i just do not want to elucidate upon them at the moment.
There are things in the world,
that revel in absurdity and will likely continue long after we are dead and gone .
let us just say things may not always appear as simple as we thought.
May tomorrow be a better day .
BTU meteringIsta makes a quality meter. I've used their systems several times. There is no such thing as
an inexpensive meter. The savings of using one boiler rather than 5 more than covers the costs. Pay the Piper or divide by 5.
Metering the heatIf all the zones, and loops are at the same temperature, then meters for the total flow (like water meters) would enable you to charge fairly.
If you add all the meter readings up every month, and then find the percentage of the total flow for each unit from it's meter, that seems fair to me.
Have you been charging for the heating up to now?
If you see the open windows of wasteful apartments, then outdoor reset could discourage that by lowering the water temperature in relation to the out door temperature.
Alternatively, you could apportion the cost on a square foot basis. --NBC
Measuring flowwill work as long as every metered branch has the same ∆T. I'm skeptical that would actually happen, even with ∆T pumps all around.
headacheFor every measure to make it fair, there are counter points. Can you charge more in an apartment, because you don't have enough radiation for the heat loss? I don't know the answer, but the question is, headache producing. Do the folks on the north side of the building have to pay more? Try and convince a person that it was fair for them to pay more for their unit, even though its the same size as another unit.
Individual BTU metersare the only way to do this fairly IMO. Just like electrical submeters we see in commercial buildings, it becomes part of the lease terms.
affordable run-time metersI completely understand why simple run-time meters are not going to be as accurate as actual BTU meters - but for those of us just watching our own systems, or not renting to lawyers....
particularly nice because you can hang it on almost any circuit - low or high voltage, AC or DC, and it's cheap enough to use as many as you'd like...