Why do you need a second electric meter to excrement with? You can read your own meter every day at the same time. As long as you record when you are drying clothes or other significant electricity burning events you should be able to test for no hardware costs.
Are you torturing the group by not doing your own meter reading and reporting back?
We are running multiple schools on ground source heat pumps. Each building has a single loop with individual Trane heat pumps running in each classroom tapped onto that loop. There is NO auxiliary heat. There are NO heat strips. Our Energy Czar believes in night set backs and holding temperatures at minimums until someone gripes. The systems are computerized to central control and the units can only be changed from the central location other than a small allowance at the thermostats.
Each building, or even portions of buildings, have different thermal mass/draft and air leakage issues/poor glazing/etc that each requires its own start up time. Some take 2 hours, some almost 4 hours if they have been allowed to get too far out of design or conditions are extreme. The water loop is circulated full time through the well field, but the compressors at each heat pump function by thermostat. The buildings have become so much easier to control that we continue to install these systems as money permits. The buildings are so much more stable that we tend to ignore old fashioned insulation/draft/weatherstrip conditions - perhaps we will get back to them as energy costs continue to spiral.
Our HVAC technicians would prefer just letting the systems run full time and maintain a steady temperature, especially when equipment is new just to run it through its paces while under warranty. The Energy Czar tends to win. I will try to remember to ask tomorrow about the whys.
Each well field happens to have hit multiple water tables, so each field is way under capacity as they are originally designed on the assumption of no significant water zones and rely on ground contact through the custom gel only. We have two sites without well fields that run the loop through a cooling tower (no chiller) and small redundant boilers with plate frame exchangers. These were the first 2 sites when too many folks were afraid of the ground source. Who knows on a 20 to 50 year cycle, but right now groundsource is far and away the most efficient, cleanest, lowest maintenance system out there. We're not walking, we're running!
Hi Jim,
I am lost...
How would reading my meter at the same time every day tell me my heat-related energy consumption?
Thanks,
Day zero meter reads 1480 Day one with no thermostat changes reads 1520 Day two no thermostat change 1570 day 3 no thermostat change 1620 Day 4 after thermostat rollback 1680 day 5 with thermostat rollback 1740 day6 with thermostat rollback 1800 day 7 no thermostat change 1850 day 8 thermostat rollback 1910 day 9 thermostat rollback 1970 day 10 no thermostat change 2020
and so on. Just read the meter every day at the same time. Do the math. Do it over enough days to factor out clothes dryers and baking festivals. If there is indeed any significant energy saving to be had by thermostat rollback it will show up with a month of measuring. Especially if you do rollback every other night.
That said I think when I feel rich I will buy
much less or more you are spending by trying different thermostat strategies. You also need to note wind, sunshine and outside temp. My heat does not run on a 50 degree day with sun and little to no wind.
Just for some perspective, last week the temperature here was 60 degrees, which melted the snow that had come down a couple of days previously.
Don't know if you gave up or got an answer but I mentioned the OSU site earlier. Being bored, I went and found it -- here's the current link. Didn't find a specific answer in the faq's, but they have a couple of contact ways you can get to them.
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hi all!
i sent this email to Alliant Energy Geothermal =============== there is a discussion underway with this as topic: - We heat and cool our home geothermally (water to air system.) We would, of course, like to decrease our costs further if we can, and so have explored the benefits of setting our thermostat lower at those times when the house (or parts of it) are not occupied. The folks who designed the heating system say that with these systems, it is best to leave the set temp unchanged. Of course, I have asked "why", but when I do, it seems that smoke starts to come out of the phone. In essence, they say that it is "best" but seem unable to say why. Might any of you know what would be best in this regard , and particularly whether the issue of thermostat setback is actually any different for geothermal systems? could you help me understand the issues involved? thanks in advance for any input! chuck b:-) ============== and i got this reply
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Dear Chuck,
Set-up of a Geo system temperature during the cooling time of year should allow a Geo system to recover the cooling and dehumidify as quickly and more efficiently than other air sourced cooling systems.
Set-back is not typically recommended during the heating time of year due to 1) a slower recovery time for heating, 2) the potential for the back up electric elements kicking in to boost the reheating rate but, at an added electric expense to you, 3) dependent on if you use a straight well water open loop or only a minimal to non freeze protected closed loop fluid, the lack of normal flows may allow for a potential for a loop to freeze up and 4) many people who own set-back thermostats are easily confused by the instructions for operating them and re-setting them.
All of these can cause contractor callbacks, they hate callbacks.
We do have a few of our regional Geo system owners who do a slight setback for heating at maybe 2 to 4 degrees F maximum for 4 to 6 hours but, all must realize the potential results.
During AC season and the daytime hours of unoccupied homes, they might also do set up to minimize On Peak energy charges when they choose Time of Use electric rate options.
I hope this helps. Thanks for the inquiry.
Leo
From: Alliant Energy Geothermal Web Forms [mailto: snipped-for-privacy@alliantenergy.com] Sent: Wednesday, November 28, 2007 9:29 PM To: Geothermal Cc: Webmaster Subject: Alliant Energy Geothermal -- Contact Us Form
chuck b:-)
Now that has a few good answers. I would not have thought about the freezing closed loops.
Howdy,
Any responsibly designed system protects against such freezing...
All the best,
...
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My thinking precisely. The response basically is a bunch of weasel-words. The upshot basically is if the aux heat issue is taken care of properly and one doesn't mind the recovery time, setback will save. For a reasonable source capacity, our experience was that while the outlet temperatures aren't equivalent to gas, they're sufficiently high the air feels "warm enough" circulating as opposed to the and as compared to air-air heat pump that felt cool...
If there's freeze-up w/ a few degrees setback so the unit runs a little less at night, there's going to be freeze up on other days as well...
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A few degrees lower is "outside the design" for a residential hvac system? I still think there's been no rational basis for the proscription given unless, as Ken says, there's a problem--and if there's a problem, I think there will be a problem irrespective of the setback.
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but on the other hand:
from your OP "The folks who designed the heating system say that with these systems, it is best to leave the set temp unchanged."
any system that is operated outside it's design criteria risks failure!
good luck with yours!
chuck b:-)
...
Well, what _did_ you mean, then???
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you seem to be reading things that i didn't say or if i did i certainly did not mean to.. oh well, have a good day!
chuck b:-)
Relative to what you would have 'spent' at the 10degree higher temperature yes.
Yes and no.
There are three intervals to consider. 1) while the temperature is falling from 'X' to 'X-10', 2) while the temperature is stable at 'X-10', 3) while the temperature is rising from 'X-10' to 'X'.
As the house cools from 'X' to 'X-10', you aren't providing any heat input at that time. *THAT* 'savings', is cancelled by the 'extra' energy you have to put back into the building the next day, to raise the temperature from 'X-10' back to 'X'. For complicated reasons, it usually takes a little more energy to go from 'X-10' to 'X' than was 'saved' by letting things fall from 'X' to 'X-10'. This differential is usually fairly minor, however it can be magnified if the -rates- at which the temperature falls and rises are different.
The heat input required to maintain the house at a constant "X" is exactly the heat losses being radiated by the house to the exterior.
The heat input required to maintain the house at a constant "X-10" is exactly the heat losses being radiated by the house to the exterior.
In both cases the rate of loss is a function of (a) the temperature differential, _and_ the quality of the insulation.
The point is, however, that the difference in heat input is exactly the difference in thermal losses, at a constant temperature. You cannot count a savings for less heat input, -and- a savings for lower thermal losses.
A 'medium-insulated' school building full of people doesn't need _any_ additional heat source until the outside temperature gets below about
-20F.
Look up how much heat an 'at rest' human body gives off, and multiply by the 25-30 bodies preset in the average classroom.
Getting the heat _out_ of the building is the issue.
At 'above zero' temperatures, it's _common_ to be venting hot air outside and pulling in cold outside air for 'make-up'.
Not infrequently, the chillers will be running, in addition.
Robert, as you said, bodies and lights make a huge load on a building. Our Energy Czar (EC) lets the buildings get cold enough that they typically require a morning warm up before the occupant load takes over. We have one 2 pipe school that requires a full conversion to either heat or cool that can be quite troublesome on those moderate days. We turn all chillers off and dump the cooling towers as we head into the freezing months. The buildings can usually be tempered by outside air. The geothermal schools eliminate this problem and allow partial usage of buildings for special events and summer school type needs.
I did ask about the setback issues. We had one series of heat pumps whose open/close valves did not have stops installed. These machines have a sensor that says if the water is too cold it prevents the unit from running rather than make ice - this issue was rectified by installing stops that never allow the valves to completely close which keeps the water circulating back to the loop. We now install all systems to run the well field pumps continuously as we have one that turns off the circulating pumps if there is no demand anywhere on the system which can allow some of the loop to reach that same "don't run" temperature. Believe it or not, the pumps have shut down several times because the building is that stable. As Robert says, lights and people can keep a large building quite warm or too warm when the rest of us need heat. We do continue to have a problem with people wanting cooling on warm afternoons turning the thermostat down to the bottom at 55°: the computer limits the units so the 55 never happens, but the units also don't come up on morning warm-up, though the rooms seem to recover quickly if the rest of the building is satisfied. He swears emphatically that no matter what system is used, intense run time in the mornings uses less energy than the start/stop cycle of leaving the system at temperature around the clock. They have put in-line monitors with recording capability on units set up each way on highly similar usage, run them for a week, then reversed the study for another week on the same units. Setback with a substantial run time to recover uses less energy than maintaining the temperature during non critical times. The setback needs to be able to protect critical needs as in not freezing water lines or baking cookies in the attic.
______________________________ Keep the whole world singing . . . . DanG (remove the sevens) snipped-for-privacy@7cox.net
"Robert Bonomi" wrote in message news: snipped-for-privacy@corp.supernews.com...
... snip
From EDEE 101 (or Physics 112), we were told that the average human body is equivalent to 100 watt light bulb as far as heat output. Depending upon age, kids in a school would most likely be considerably less.
Mark & Juanita wrote in news: snipped-for-privacy@news.supernews.com:
You haven't seen my 11 year-old granddaughter - 250 Watt is more like it.
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