Spend the money for good heat loss calc?

[JP11]

Morning. I'm getting closer to starting my boiler project.

House and garage is about 6k of heated square footage. High ceilings, all radiant.

I installed a hour meter on the boiler and have been tracking usage this summer and fall. I can W.A.G. at the heat generated. I use a mixture of HHO and homebrew biodiesel, so the calculations will be close, but not too scientific.

I'm having an energy audit done. House is only 3 years old, but I'd like to see with the door test, and thermal camera if I made any mistakes in the insulation install. A few hundred bucks is worth it for the long haul.

Question.. for a couple hundred more I can get him to do heat loss calcs on the whole house. Should I bother? Will the real world burner hours logged against daytime temps get me close enough? I already know I'll be going with a 60k Vigas with 1000 gal of storage (two 500s vertical, parallel - man I'm happy I went with TALL ceilings in the basement. It's 10'5" or so to the bottom of the floor trusses)

So I'm really just doing calcs for pipe size and circ capacity from boiler to storage right? The storage will feed right into my buderus boiler, and using my normal 5 zones for the house circs and the 6th zone of indirect 80gal DHW tank the boiler sits on.

Learning a lot here. Gotta get cutting more wood. 70 acres of blow downs and dead standing to clean up. Got the tractor, utility snowmobile and all the toys to put to "work"

Thanks in advance
JP

 

[in hot water]

How many zones in the home? Are all the areas heating okay, any cold spots? I suspect a heat load was done before the radiant was installed? There must have been some design to indicate how many loops per zone, flow rate, boiler size, pump size(s), etc?

It would be interesting to see how a "as built" load calc would compare to the design load once you gave the info from the energy audit. Infiltration, which the blower door will indicate, would be an interesting number.

If all heats well, I'm not sure a load calc would help much, unless you were considering sizing down the wood boiler choice.

hr

 

[JP11]

No, boiler installed will be much larger than oil boiler. I wanted a bit oversized to be able to "catch up" and still supply heat load of the house.

No cold spots in the house. 5 zones. 3 upstairs (running stapled under floor radiant at 140 degrees) 2 zones in the concrete running 100 degrees or so.

On the coldest of days, circulators really never shut off, and burner will run maybe 16 hours of the day.

that's just from my memory.. hour meter will confirm my recollections and guesses at burner hours.

Tanks will hold about 600k BTUs or so.. I'm guessing that means about 10 hours of load on the coldest of days.

The biggest unknown is how much the wife will feed it when I'm away for a week at a time. I'm thinking once it's in and wood is right there, she will do it.


JP

 

[henfruit]

When would you like the boiler delivered? Give me a call, thanks.

 

[JP11]

Lol.. you guys made the sale already.

I still need to bring the wife by to see yours and fire it. might be after xmas.

Tanks are headed to the welder next week. Need to figure out taps and such.

Planning.. 3/4 on the top and bottom. Use a truck rim for a stand for tank base. (put a hole thru rim for 3/4 ball valve for drain line.) air purge ball valve on top.

Planning a 2" weld o let in top (right where curve of tank starts) and bottom on both sides of tank.

Figure i've got all the bases covered then. Gonna have top and bottom temp probes in tank.

Planning to get storage and piping all done this winter. summertime to tap into the boiler and get it running.

JP

 

[bpirger]

If the house is warm and you have no complaints, I'd say the heat loss calcs would just be fluff...you'd be better spending the money on getting ahead in dry wood....or save it for all the copper!

16 hours a day on the current boiler is a lot of running. Do you know how many gallons per hour is it? 6K square feet? How much is garage/shop and and what temp? I'd say you can get close enough knowing these things. Sounds like you are in a 1.25" primary loop anyways, and likely will need to feed that primary loop with 1.25" from the wood system. Then you should not have any problems supplying the heat to the system....

I see you are talking about 3/4" on your storage tanks? Is this for water flowing in/out? I'd think they would be bigger...but I'm not an external storage guy...I burn a Garn.

 

[JP11]

You missed what I was saying with lines.

I wanted to put a 3/4 tap in top and bottom. One for air vent when filling, other for draining of sediment.

I THINK the house current circs and lines are 1" at the boiler. think i'll be inch and quarter or maybe even inch and a half from wood boiler to storage.

Ok, math time

I run a blend of about 65 to 70 percent biodiesel. 118k btu's per gallon
HHO is the rest of the blend. 129k btu's per gallon.

Running a .85 nozzle at 140psi

Just from my recollection it's running 16 hrs when it's 10 below outside. Hour meter will tell the tale this winter.

1200sf is garage.. 60 degrees
1900sf is basement. 66 degrees or so
upstairs to all of this is 68 degrees.

I really think that my boiler is just a bit undersized (well maybe JUST right if I were running HHO only)

When I'm home, (I go away a week at time) I really don't care if I do several burns a day, or tend it. But I'm really hoping that it will work out to a couple tending events a day for my wife using the storage.

Sounds like the hour meter will supply good enough data, and it's not worth it to do calcs from the audit guy.

JP

 

[nate379]

Curious what size your boiler is?

 

[JP11]

Buderus 115 I think it's called.

Wanna say the sticker on it says max GPM of 1.25 with 129K btu or so. Not home so I can't read sticker. It's got the beckett burner on it.. a combo they don't offer anymore I heard. I got it due to being able to use aftermarket pump for Biodiesel compatibility.

JP

 

[bpirger]

I have the same boiler, with a Riello OC-3 indirect burner. So do you mean 0.85 gallons per hour? Or right about 100K BTU/HR. So on the coldest day, or -10 anyways, you are thinking about a 1.6M BTU/DAY load. So that is more or less worse case then. That'd be 54K BTU/HR....6000 sq ft....so that sounds in the ball park to me.

I don't see what more a heat load will do...other than let you compare theory with reality...and you can twiddle the numbers yourself just as good. I agree that looking in the thermal IR at your house will help you much more than a heat load!

Also sounds like you have the 1.25 or even 1.5" plumbing plumbed....seems like 1.25" would be fine. Sorry I misunderstood your ports. For what it's worth, I always place two valves in critical places I don't ever want to leak, like the bottom of the storage tank, just to greatly minimize the frustrations if one should leak.

Oddly, I have a 1.5" ball valve on the end of a 1.5" black iron pipe that seems to leak a tiny bit every now and then, through the valve, not around the threaded fitting. Not a constant leak, but every now and then I notice some drips on the floor. One of these days I'll place the caps on the ends and won't see the drips any more. I'm glad it isn't the valves at the bottom of the garn for the drain! I have two on that one...

 

[JP11]

Yes.. .85 GPH.. but isn't that rated at some lower pressure? I'm running it up at 140psi. Bio isn't quite as hot a flame. I run higher, and I even painted the inside of flame tube with chrome paint. The photo eye wasn't seeing a hot enough flame without that.

That was when I ran straight bio. I've found that a bit of HHO pumps up the heat, and runs a bit cleaner in the boiler.

I still clean it about every 5 or 6 weeks. A couple hundred dollar ash vac, and a nozzle is a small price to pay for buck a gallon oil!

I did the math comparing to wood... I came out at about 195 dollars per cord to produce the BTUs that I'm getting from the oil boiler. So.. i can't quite justify buying wood.. but with so much wood surrounding the house.. and the bonus of having TWO heat sources not dependent on anyone who rides a camel.... I figure it's worth it.

JP

 

[nate379]

Seems like a small boiler to heat that much space.

I heat about 2000 sq ft between my house and garage, all of it slab heat. The boiler is 90,000 or 95,000 BTU. If I have a couple zones calling for heat, and maybe the water heater needing water as well (indirect tank) the boiler has to do all it can to maintain the temp.

I can imagine your boiler running near non stop to heat that much area. It'd probably be ok with just the house, but add in that big garage and that is alot of real estate to be heating!

I'm not quite following the reason to put a water storage on an oil fired boiler though??

 

[JP11]

Nope.. buying a vigas wood boiler. Just gonna put in the 1000 gal of storage first. I'll plumb it up and have it ready for spring. I'll get the boiler in this spring.. and by then I'll be ahead a year's worth of wood.

My wife liked it when I started pointing out all the trees that were already blown over, and just going to rot. I've got a kubota cab tractor and a wide track skidoo with a nice sled behind it. That's year round wood getting on my lot. Just gotta get out there and do it.

I do think the oil boiler is right at the minimum for what the house needs. If I was trying to keep everything 70 degrees I don't think I could do it with my bio mix. I just need that extra 15% or so of heat. It is radiant, so once that slab is warm it stays warm. It sure takes a long time to swing the temp in those basement areas though.

JP

 

[bpirger]

Ideally your boiler would be rated the same as your max load, as it burns most efficiently with long burns....so yeah, I think you did it right. of course if it can't keep you as warm as you want, that's another story! My 115 is setup with the 0.6 gallon/hour nozzle, don't know about the pressure, I'll call it "standard". But I'd agree, a higher pressure must burn more...

I have a huge thermal mass too, concrete, and indeed it does take a long time to come up. But I love it...nothing like walking on a warm floor.

As you said, you have the toys to collect and the wood just sitting there....the trick is to go out and get it in. I've been doing so the past few weekends as well, working on next year, and hopefully in the Spring I will be working on the next, next year to get ahead. I have 44 acres of woods. My hardest part is dropping trees that somehow I think someday might be saw timber. But I have a good deal of soft maple, which supposedly isn't worth too much. But the idea of cutting what could be saw timber is just dumb!

I started to cut in a new "road" through the woods, so I figure anything in the pathway will just come done, regardless. Of course, when I get to a 12" straight cherry, I'm sure the road will take a little jog. LOL It never ends!

 

[JP11]

I cut the high dollar vernier wood out of the lot (just under 70 acres) about 7 years ago when I bought it. So I have lots of skid roads, albeit very wet in some spots. The skandic and sled will come in handy there.

Logger told me.. Leave the ash and the oak alone (there are lots of 10 to 12 inch trees this size) and he would be back in 15 years to cut it again. As I got back half of my purchase price of the land, and didn't lift a finger. I think I'll listen to him. I had some really nice 50 and 60 year old oak come out of there. My driveway did take a few turns thru the good oak stands. My wife never knew WHY the driveway went where it did.

I really think I can get by just about forever on stuff I can get close to my roads. I really would like to make one loop around the whole lot. I have one border of the property that's about 2600 feet long. Figure I cut it 8' wide.. that's a lot of trees. I bet I have 2 or 3 miles of road, driveway, and trail now.

Anxious to burn... but it didn't make sense to rush it for this season. I'll spend the winter getting ahead on wood.

Hour meter shure is clicking along now. Was running just over an hour a day in summer months for DHW.

JP

 

[bpirger]

That's what mine ran for DHW during the summer, just over 1 hour a day. I didn't have a timer though...though the Tekmar controller will tell me how many hours the boiler fired. When I was burning the woodstove, and maintaining the concrete floor at a minimum of 66 or so, I think I only burned about 2-3 hours a day...so not much oil to keep the floor minimum up.

Yep, sounds like you have a good plan. I hope those Ash are still worth money in the future...the Emerald Ash Borer is very soon to these parts, and apparently it is wiping out all the ash. Many folks around here are taking them down now all they can to get the timber value before they all turn into firewood. Something to think about...not sure how Maine is with the EAB. Just a note, a logging winch on the back of your tractor sure does make things easier getting the wood out, should you need to go back off the logging roads a touch.

I bought my land in '98. The story I'm told is that the 168 acres up here was owned by an older couple from NYC and they used to have a camp of sorts, burned down, the kids didn't want the land, so they sold it...for $25K in '97. The fellow took $150K in timber out, then sold the 168 acres in three chunks. I bough the smallest with 44 acres for $18K. I wish I had bought it all...though wasn't possible in '98 for sure. So talking about getting your money back! Gas lease in these parts will bring it back though...like it or not. Turned down the $2K/acre offer a few years ago...expecting to see northward of $5K in the next year or so as NYS opens up to the mercy of the drillers. Mixed feelings on my part...just wish they'd do it more cleanly and safely. It'd be nice to be sitting on 168 acres when that all happens!

Sorry for the off topic.

Do you have a model number for your timer on the boiler? Is it a digital or mechanical deal?

 

[JP11]

Wow, to be the guy that got that land for 25k. Always right place, right time. I thought I did well at under 1k an acre.

Hour Meter was a AC powered "hobbs" meter. Found it on EBay I believe. I just tied in the leads to the cut off valve I installed. Yeah, my burner is a bit of a cobbled up mess. I added a full time fuel pressure gauge, 5 second delay cutoff, biodiesel compatible pump and a nozzle line heater. Can't resist burning fuel I make from leftover fry oil. Total cost of my bio is a buck a gallon!

For now.. I'm gonna skip the winch. I don't wanna drag the wood thru the mud and spend more time sharpening saw chains. Gonna try to cut stove length and stack in the bucket for now. I'll do the same and fill the sled in winter. We'll see how the plans in my head work. In another few weeks my wife's busy season will be over. Will be good exercise for us both. Have to start slow with this wood thing so she won't hate it.

JP

 

[henfruit]

I bought 150 acres for just over 300 an acre.