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The Sizer strikes back...
Constantin
Member Posts: 3,796
So, I'm having a bit of fun with Excel. As you may all recall, I put out a NPV calculator and a heating system sizer that's based on the installed infrastructure. It's an educated guess, but better than nothing! The latest update is enclosed below.
Start at the top left, then start by selecting and filling out the white areas. Further down, I give you the option of selecting a number of different heating systems to comparison shop. As with most things in life, the time horizon (i.e. how long do you want to look out) is a big factor.
This little excercise in mainting some Excel skills may or may not be useful, so I'd like your feedback.
Start at the top left, then start by selecting and filling out the white areas. Further down, I give you the option of selecting a number of different heating systems to comparison shop. As with most things in life, the time horizon (i.e. how long do you want to look out) is a big factor.
This little excercise in mainting some Excel skills may or may not be useful, so I'd like your feedback.
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Comments
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Hmm....
I would like to do that buh i am not good at computer stuff. i have dream weaver and i couldnt even make the pictures show up much less add variations to it.i am too stupid when it comes to these programs...how ta do this? because i am interested in your contributions and work...0 -
Great Stuff!
I'm paying $2.29 for #2 in Seattle... Think I'll go play with the spreadsheet and see how it works.
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Wow!
Those prices make me feel better about what I'm paying for my #2 up here...
Is the price driven by low demand in WA or does the state lack any refineries and hence the stuff has to be trucked up from CA? It's just bizarre to have such high prices considering how much closer you are to the Domestic sources than I...
As for the sizer, I'm already thinking of several ways to improve it, such as splitting the equipment purchases and fuel savings so that recurring equipment costs, etc. become more visible as a function of time.0 -
Hi Weezbo!
The file up there is an Microsoft Excel file. To use it, you'll probably need a copy of MS Excel (part of the MS Office suite), though it could perhaps run on OpenOffice as well (which is free, IIRC).
What may be getting in the way of your enjoyment with this file is that our browsers sometimes misunderstand the files we save to the desktop. Instead of saving the file as "Sizer.xls", it may have been saved with a different extension like ".cfm", which then confuses the heck out of your computer.
Simply rename the file on your desktop to "sizer.xls" (w/o the quotation marks) and then double-click it. Now, MS Excel should launch and open the file for you. Cheers!0 -
I'm staying with electric DHW!
Constantin, I think you have a glitch. I put in oil for the heating and electric for the DHW. The DHW comes in at $10, even at the default 16¢ rate. Also, for the DHW the user should need to set some type of usage although few of us would likely have more than a WAG at out annual DHW usage.0 -
Recommended improvement
Not all gas is 100,000 btu/cubic foot. Especially up here at altitude. There needs to be a place to adjust that factor. Cool tool though. Your Excel skills are much greater than mine. Thanks for sharing.
ME0 -
ah, but you can...
.... just scroll over to right, you'll see the fuels section with caloric contents...
I figured putting that into the main section was a bit too geeky, but I guess I can see the need...0 -
Some good observations...
... asking people to estimate the fuel usage on a WH is a WAG at best. As we both know, the actual efficiency of gas units is very low, while electrics usually have pretty low standby losses.
I'll have to think about how to do all that best...In the end, I'll probably have to put in some switching to allow different menu choices for different types of water heaters. For example, GSHPs produce free hot water in the summer, etc.
BTW, the "summer fuel use" section is set aside for WH energy consumption. Did you enter your electric kWh usage in that field? Or better yet, can you send me the file by e-mail so I can have a look at the changes you made? I'm simply curious because I can't replicate what you're describing.0 -
*~/:( i dont have any thing thats opening it for me
so i tried to send it to my buddy so he could re name it or whatever so i can make it go
buh he has too many things in his mail its over loaded..hes been on vacation for months in New Zeland ..The time has come to get the office xp the homeowner thing just bytes...i have things from cal tech mit all over the place and i cant open any of them...i tried what you suggested though...oh well i save for a rainy day...maybe one of the ladds will come by to see if i am dead or alive and i will make them figure out how to make it go:)only is is its like 40 below zero lately an nothin wanna go 0 -
i have an idea you can assigne 10 000 btuper day per person
or about 3 kw ish per person per day...0 -
Check your email
I sent you a copy with the proper file extension that way...0 -
Calcs
Thanks, the summer fuel usage was the missing variable but that might be less than obvious since DHW is a year long thing so it might be better defined. Does your model account for electrical consumption of the heating equipment?
On the formatting side, you might want to be a little bit less restrictive on cell entries. I'm in the great white north where our moose are metric so in fields like annual consumption, I'd much rather type in =2200/3.7853 unless you are ambitious and want to add units of measure to allow for oil in litres and gas in M3?
The easiest way to get the initial DHW figure might be to input the expected current annual cost. At worst they use their sticker. For me I figure it is just under 50% of my non-fixed electrical bill, or somewhere around $500. Easier to start with that number and work backwards to BTUs for comparison than trying to build it up to the annual total through iterations.
When are you building a home heating model that can handle diverter tees? 0 -
Cool Tool............
Constantin,
I love this tool. I'll play with it sometime when I have some free time
JR
To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"I am the walking Deadman
Hydronics Designer
Hydronics is the most comfortable and energy efficient HVAC system.0 -
Metric / Imperial it will be...
The switch is easy enough to make. In terms of heating outputs/ heat loss and the like, would you prefer Joules or kW?
Diverter T's? I don't know enough about them to know if I could model them... describe the problem and we shall see...0 -
Metric / Imperial it will be...
Litres are needed of course and a therm I believe is 2.78 M3s. As for input/output/heatloss, BTUs are the norm here although KWs is what it most likely should be.
Diverter tees have a venturi on the second tee so that the main effectively resists the water and backs up the pressure just enough so that it goes through the previous branch. I have no idea about what this cv level is. I've struck out trying to find out what they are for Armstrong cast iron units but I am sure that they are much the same as what they are for Monoflos. The tough part is, that the bigger the distance between the tees the more resistance to the branch. Add to that that another branch might start in between an existing pair of tees or that dropping branches uses diverter tees at both ends and you can see how this would be a noble exercise. It's like a series of partial dams with high-flow bypasses that go to emmitters that lose various BTU levels dependent on temperature and flow which depends on the diversions and previous emmiters. My head hurts thinking about it.0 -
Sounds like a lot of recursive loops...
... computationally intense but usually can be done. The big question is, how accurate is the info going in?
... I've done similar optimizations when it comes to battery calculations, for example, where the state of charge dictates how quickly you can charge them... the model that's on my web site now is very simple by comparison...
I once had to do material flows inside a recycling plant... lots of metals, processes, etc. to keep track of. This sounds kinda similar, though the inter-relationship between flow, pressure, and BTU content is a definite monkey-wrench.0 -
Hi John,
It may not save billions of BTU's like your formula will, but it's a fun little excercise in programming. I look forward to your comments. Cheers!0 -
$1.70/therm nat. gas?
Is that really what you pay there?
Ours is around $.90/therm.
Cool tool though. Thanks!!
I'll mess with it some and get back to you.
Mark H
To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"0 -
Excel Viewer
Weezbo, you might want to try this, but I can't vouch for it since I never used it:
Excel Viewer 2003
Open, view, and print Excel workbooks, even if you don't have Excel installed. This download is a replacement for Excel Viewer 97 and all previous Excel Viewer versions.
The link is:
http://www.microsoft.com/downloads/details.aspx?FamilyId=C8378BF4-996C-4569-B547-75EDBD03AAF0&displaylang=en0 -
$1.7/Therm? ... shouldn't be...
... we currently pay $1.5/therm around here. Naturally, feel free to change any values, see how hard this makes you all laugh...0 -
Grid
Constantin,
One thing you might want to add is a small embedded graph that plots energy cost lines. Maybe cents per MBTU or something, so that a person can compare energy costs in common units at varying efficiencies. Cost on the Y axis and effeciency on the X axis maybe working downwards from 100%? For me, oil at 70% is almost as expensive right now as electrical at over 95%. I did a huge spreadsheet like yours a few years ago. I put each componant type in separate amortization schedules (boiler, piping, emmitters, controls, storage tanks, etc.), added fixed costs and regular service or contract fees, as well as plotting future energy graph trends with full risk analyses. When I got the model complex enough, my crappy old heating system started looking best for any sub 20 year NPV or IRR calculations. I had to ditch the model because I still wanted a new system at some point, just for the oooo factor. Models never take that into account.0 -
GADZOOKS MAN!!!!!!!!
Still outta' this whirl!!!!!!!!!
I used to play with Excel too, had a few neat little sheets that were quite helpful. Nothing this involved.
I think you need come work with us for a few weeks. Get to see see things from the other side.
I'll pay you 2 dollars a day, but the experiance will be priceless!!!
Mark H
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Woah buddy that helped *~/:)
thank you both ....now i see the deal here ..the excell thing workie and the Sizer works too hurray! i can check it more tomolly this is to molly by golly well i sorta checked the deal out and some of this i cant enter information maybe i figure it by later today...i liked the idea of KW M[3] and the imperial gallon is real enough too.then the Angelterrans can also use i noticed lots of lines on the left is that so one can print pages ? i like this look .Thanks...And say the metric moose i like the thought *~/:) 0 -
Does that include room and board?
Be careful with these sorts of offers, you might get what you pay for! :-)0
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