(Heat Loss Calculation) Tonight - 1/7/15

Reply

  #1  
Old 01-07-15, 05:33 PM
Member
Thread Starter
Join Date: Oct 2008
Location: USA
Posts: 2,852
Likes Received: 3
(Heat Loss Calculation) Tonight - 1/7/15

Here in the Midwest, it would be a good time to measure your home's heat loss. At 7:05 p.m. the outdoor temp was -5 deg. Tonight's low is predicted for -15 deg. I have an elapsed-time meter on my boiler's burner. I've already measured the input and net heat output of the burner, Btu per hour, by clocking my gas meter. Piece of cake. More accurate than calculating using computerized heat-loss programs.
 
Sponsored Links
  #2  
Old 01-07-15, 06:31 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Likes Received: 1
It's a balmy 13 here in NJ, but with this wind, I think the wind chill is down around your temp, maybe lower!

From 5 PM until now, 9:30 PM I've burned 1.2 Gallons.

1.2G X 139,000 BTU per G / 2.5 hrs = 66,720 BTUH
 
  #3  
Old 01-07-15, 06:50 PM
Member
Join Date: Dec 2012
Location: USA
Posts: 137
My friend has some thermal camera's at work and he had just finished using it. He dropped it by my house as it doesn't have to be back for 1 week. Flir E4.....

I REALLY need to get to some of the areas and fix some insulation. A new front and back door are definitely in order also.

15ft east wall on slab with no HWBB has a very dark blue streak all the way along the floor corner. Not much to do with that except maybe dig outside and put some ridgid board along and then cover it somehow.

I'll have to check hours on meter before work and in the AM.
 
  #4  
Old 01-07-15, 07:02 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Likes Received: 1
Bring that FLIR down Seq, I'll buy the beer.

Dropped another degree in the past half hour, 12 right now
 
  #5  
Old 01-08-15, 03:42 AM
Member
Join Date: Jan 2010
Location: North East Kingdom of Vermont
Posts: 2,533
I woke up to -29F this morning; but that's a whole lot better than the -48F we had on 1/9/2004.

My boiler has to struggle a little bit at this level; it's running continuously, not quite able to achieve the +68F cut-out.

I'm not complaining . . . . the power is still on and our water hasn't frozen.

It's gonna be a good day !
 
  #6  
Old 01-08-15, 10:05 AM
Member
Join Date: Dec 2012
Location: USA
Posts: 137
NJ Trooper

Bring that FLIR down Seq, I'll buy the beer.
If I didn't have 10 things scheduled I'd do that (even w/o the beer) just for all the help you provide to others. Good Karma!

Does this calculate right? 12 hours of time (10pm to 10am), 1.00 x 60 nozzle, 3.7 hours run time = 42,858/hour.

I guess this also means my WBV-04 is "slightly" oversized ( I think it's 112,000)
 
  #7  
Old 01-08-15, 10:19 AM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Likes Received: 1
Does this calculate right? 12 hours of time (10pm to 10am), 1.00 x 60 nozzle, 3.7 hours run time = 42,858/hour.
Yes, but only if you are running the oil pressure at 100 PSI. Higher pressure which is typical these days will increase the GPH and thus the BTU
 
  #8  
Old 01-08-15, 06:43 PM
Member
Join Date: Dec 2012
Location: USA
Posts: 137
Yes, but only if you are running the oil pressure at 100 PSI. Higher pressure which is typical these days will increase the GPH and thus the BTU
OK help me out on that one. From what I read (no gauge to check yet) mine is set at 155 psi is what is spec'd according to all the info I found on it.

How much fuel would that be on a GPH basis with the 1.00 x 60?

By the way it was 9 degrees when I left at 10pm and 12 when I got back at 10am.
 
  #9  
Old 01-08-15, 07:11 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Likes Received: 1
There's a nozzle chart in this PDF... page 13

www.delavaninc.com/pdf/total_look.pdf

A 1.00 at 155 PSI is probably right around 1.25
 
  #10  
Old 01-08-15, 07:13 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Likes Received: 1
One thing to keep in mind...

This number is 'GROSS' and includes any heat going up the chimney.

It might be a safe guesstimate to reduce the BTU number by about 15% to account for boiler efficiency.
 
  #11  
Old 01-08-15, 07:23 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Likes Received: 1
Looks like past 24 hrs I've burned about 10 Gallons... OUCH!

Comes in right around 60K BTUH Gross... 51K if I knock off the 15% up the chimney.
 
  #12  
Old 01-09-15, 07:12 AM
Member
Thread Starter
Join Date: Oct 2008
Location: USA
Posts: 2,852
Likes Received: 3
Are you people with oil-fired boilers seeing significantly lower oil prices yet, like for gasoline?
 
  #13  
Old 01-09-15, 07:18 AM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Likes Received: 1
Yes. Last year my final tankful was 3.59 / G

I just had a fill up about a week ago and paid 2.35 / G

Sure wish I could stockpile...
 
  #14  
Old 01-09-15, 08:01 AM
Member
Thread Starter
Join Date: Oct 2008
Location: USA
Posts: 2,852
Likes Received: 3
As long as the fracking glut keeps coming from North Dakota, we should all be happy. That Bakken crude is being shipped to refineries via rail tank cars, and Midwestern railroads are severely strapped for capacity - buying additional tank cars and locomotives, laying new track, and hiring more people. I have a friend in Bismarck, ND who says that there is now a major labor and housing shortage in the state.
 
  #15  
Old 01-09-15, 04:23 PM
Member
Thread Starter
Join Date: Oct 2008
Location: USA
Posts: 2,852
Likes Received: 3
Here are the results of overnight 1/7/15 (which wasn't as severe as forecast):

1/7/15 7:05pm -5deg
1/8/15 8:05am -3deg

Burner runtime = 8.8 hr

Ave heat loss (based on net boiler output) = 84,345 Btu/hr

Duty cycle = 8.8/13 = 67.7%

(I had collected the same type of data five years ago in 2009: 88,725 Btu/hr)

For comparison purposes, my calculated heat loss, using the Slant/Fin program, is 106,000 Btu/hr. Calculated heat loss is 19% above the higher of the two measurements. I would attribute that mainly to the safety margin built into the Manual J calculations, plus neither test was at full design outdoor conditions. Anyway, my boiler seems to be about 15% oversized.
 

Last edited by NJT; 01-10-15 at 11:28 AM.
  #16  
Old 01-09-15, 06:36 PM
Member
Join Date: Dec 2012
Location: USA
Posts: 137
Yes. Last year my final tankful was 3.59 / G

I just had a fill up about a week ago and paid 2.35 / G

Sure wish I could stockpile...
$3.29 / G Back in April
$2.77 / G November 3rd '14

$2.13 / G listed for 200-299 gal as of today at the same dealer.

NJT do they have dealers listed on the codfuel.com website by you? One "stealer" by me has emergency service listed. 24 hours per day, 10 gallon minimum, 30 gallon max, credit card only. 10 gallon price $6.25 per gallon

I think yahoo had the article about oil traders actually "renting" some supertankers (2-3 million gallons) in anticipation of the prices going back up.
 
  #17  
Old 01-10-15, 04:13 AM
Member
Join Date: Sep 2014
Posts: 10
I've been tracking my boiler but only in 24 hr increments. My control board only lists in hours but here's what I got.

High - 17 low - 0
1/7 7:00am 904 hrs 14116 cycles
1/8 7:00am 912 hrs 14200 cycles

I'm guessing it could be anywhere in the 8 hour range, so I'll say 9 hrs of runtime in 24 hours. That makes 37.5% duty cycle. Temperature on all three thermostats was locked at 70. My boiler is 117k btu output,140k btu input, so that's 43,875 btus averaged. Can't wait to make changes when this heating season is over.
 
  #18  
Old 01-10-15, 10:40 AM
Member
Join Date: Jan 2014
Location: USA near Boston, MA
Posts: 650
Likes Received: 14
gilmorrie,

Is this a typo?

1/9/15 8:05am -3deg
It should be 1/8/15 to get the 13 hours you used in

Duty cycle = 8.8/13 = 67.7%
right?
 
  #19  
Old 01-10-15, 10:45 AM
Member
Thread Starter
Join Date: Oct 2008
Location: USA
Posts: 2,852
Likes Received: 3
Yes, the second data was at 8:05 am, 1/8/15. The thirteen hours spanned the evening and early morning hours. Thanks.

[NJT fixed it]
 

Last edited by NJT; 01-10-15 at 11:29 AM.
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes