Heat loss by usage?

SWEI

4Johnpipe said:

Just installed an HTP EFTC-140F and will tweek it

Nice unit. If they'd build a 60-70k version I could sell them all day long.

SWEI

Shrink the burner and grow the tank.

jonny88

OK so where is the answer.Boiler+water herater.HTP or Mod con plus indirect or combi.Homeowners the customers if you are out there please chime in.

SWEI

That would work, but 50-60k (presumably with a minimum firing rate of 10-12k) would be even better in this market. A 40 gallon tank would probably be adequate, and could have a smaller footprint.

jonny88

Ok so 55 gallons eliminates p/s and acts as a buffer tank.Still concerned with 3.5gpm on domestic.Please correct me if I am misunderstanding this.

SWEI

Completely understood.

We are replacing mostly 40 gallon conventional gas tank heaters (net outputs of 30-36k.) Our groundwater just not that cold down here -- typical frost depth is 12" or so.

SWEI

LPG customers can be persuaded spend a few bucks given their pain level (~$3 per gallon.)

Natural gas costs about $0.60 per therm here, including all taxes and surcharges.

4Johnpipe

Thanks guys!
@RobG The gas pipe is strapped from the ceiling just out of frame and it is hard piped into the unit.
@jonny88 HTP has several units. See attachment of an option to increase hot water capacity with a storage tank and pump for this unit. The unit will run the pump. I install these in 2 and half bath homes as you see here. I always include chnging shower heads to current GPM codes @.5 GPM's. I have never had and inssue with the 3 we installed about heat or hot water. Take a look anyway at attachment.
Vers Flame is the Pioneer with the flat plate and circulator included. Have one of those installed and it is awesome on use and fuel.
We have the Versa installed also which is great when your heating is below 130K BTU's and the Pioneer is the work horse replacment for the conventional boiler replacements.
Stay tuned for smaller...The UFT is hitting the market and it is a 10 to 1 trun down. The 120K BTU will modulate down to 12K.
Keep an eye for the 80K...yes that would be 8K low fire!!!
Another great feature is you can derate these units at the controller. This allows me to set the BTU on the 120 to say 80K and it will ramp up to 140 only for domestic hot water.

Must be classified I can attach file...

4Johnpipe

At design conditions if the heat loss is only 80K you can lock out the boiler from ramping up to 140K. Prevents short cycling. The ODR and curve will begin at 80K at design.

4Johnpipe

No programming failure just another tool or option. Yes then system is very sophisticated in that it senses supply, return and boiler water temps. Most if not all mod con boilers will ramp up to a maximum BTU then modulate down depending on flow rate and supply and return water temps. This feature just holds the boiler from running up to its maximum output when it is not needed. The ODR with the heating curve set points will take over from there depending on the outdoor tempurature of course.
I am pretty sure Bosch Buderus does this with some of there models it's just a bear to set up.
This model does have a 8 or 6 gallon buffer tank. So with primary secondary piping it doesn't take long to get the boiler loop up to temp...if we don't need the full 140 to send 180 degree water to the system side why use it? The boiler circulator will modulate or vary flow also sure...but why create the additional BTU if we only need it for domestic hot water?
It's really just an attribute of HTP striving for efficiency...

jonny88

@4Johnpipe ,thanks for all your feed back.As you can see there is a lot of interest in the product.How many units do you have out there and since you use them all the time I am guessing failure rate is very low.In NY where do I get parts etc.

4Johnpipe

@jonny88 Emmerson Swan is the rep here...you can go on HTP website and get locations. I am pretty sure Blackman is a stocking distributed. We started installing them about 2 years ago. Before that it was not easy to get them. Our first one was about 4-1/2 years ago because of a space constraint. Since then Rich McGrath and myself have been actively pursuing the product and Emmerson Swan. We just recently had a good solid supply house take them on as a stocking distributor.
We have 3 Pioneers, 1-Versa Hydro Solar, 1-Versa Flame, 4-EFT floor combi units, 3- residential tankless and over 12 Pheonix water heaters in various sizes one of which is the power plant for 5 hydro fan coils for forced air. We have 4 complete hydronic jobs one is starting Monday. They all will have HTP.
I could have installed a lot more tankless units and Pheonix units had I had a stocking distributor.
We had a few minor issues that were rectified immediately.
I can't say enough good about Mike Oppel from Emmerson Swan and HTP as a company (we were up there a few months back and going again end of summer) and there tech support and training.

RobG

How does the turndown on the firing rate affect modulation?

4Johnpipe

It wil modulate from its low rate of 28K all the way to the field set max rate (the programming is only available through tech support not in the provided start up manual). It does not change the low output (wish it could). The venturi is a fixed component as well as the minimum fan speed.
Who knows maybe that is coming in the future...

njtommy

I'm really waiting to see if they are going to be able to do really large turn down ratios with the tankless mod cons down to around 5,000 btus from about 100k make. Or even lower just to be able to do the really small zones.

SWEI

Sermeta has been claiming 40:1 for a couple of years now http://www.sermeta.com/en/product/bluejet-burner/

njtommy

That's a huge turn down ratio. Never heard of them tho.

SWEI

Sermeta = Giannoni

Robert O'Brien

http://www.energyvanguard.com/blog-building-science-hers-bpi/could-an-energy-code-really-be-so-simple?utm_source=hs_email&utm_medium=email&utm_content=20368253&_hsenc=p2ANqtz-_2Simd8cm7UYV-Vt6QcxPOmPr7a2u4PUNCPZKILdvO-_aSjf9i1TemyzGxiUDkMOcl9g7diRDcUYzeO3EoIj_FSipkq8vlb0AlloXlIBCqtl_rtPk&_hsmi=20368253

Rich_49

I am curious why you would highlight that blog post from Allison within this discussion ?It does not validate the method you stated would save us all time while still running the risk of oversizing equipment . i thought we had seen the last of this discussion .
Once again I state , If an individual uses past fuel usage from a terribly performing appliance as a basis for sizing he WILL oversize the new equipment , not might , WILL . Take into account also that the building may also be undertaking air sealing and insulation measures and you've done an even worse job .
Way to perpetuate the wrong way Robert !

Robert O'Brien

It highlights that there are other ways to reach the same point. But I guess that is lost on you,Richard!

BobC

It's just another method to gauge energy use. If you did it every year you could spot a problem, then you could start to look at what was going on.

Bob

Robert O'Brien

BobC said:

It's just another method to gauge energy use. If you did it every year you could spot a problem, then you could start to look at what was going on.

Bob

Of course it's not as acurate as guessing at R values and infiltration factors!

BobC

I've spent my life in engineering, you don't really know what your dealing with until you measure it! That is the way we got to the moon, we experimented and measured EVERYTHING.

I was in about to start in a vocational high school when Kennedy gave the speech about going to the moon in this decade. We all took that speech to heart and we made it happen. We didn't have to import H1B's to do the work, we figured out how to do it ourselves.

The country seems to have lost it's way, we desperately need another moon project.

Bob

Rich_49

2 identical houses right next door to each other , same occupants , everything . The exception is 1 home has an oil boiler with a tankless coil the other has an electric water heater . I guess you will get 2 different sized boilers when in fact they should be identical .
The house with the tankless coil will use about 200 gallons of oil while it is not even the heating season . Same can be said about gas systems . How do you determine how much fuel was used for DHW , cooking , clothes drying .
I will also add that everyone does not guess at r values and ACH numbers but instead are quite capable of layering and taking things like thermal bridging , solar heat gain . shading , wind and appliance loads and individuals in rooms all into account without making hap hazard guesses . Then there are those of us who charge for the time that is so precious to you that you are willing to possibly oversize equipment , all while the industry is trying to survive

BoilOver

Really enjoyed reading that article. One question: given a design temp of 0 and a base temp for hdd of 65, why do you multiply gas usage/hdd/24 by 70 and not 65?

I have an Adobe home and am getting a variety of boiler size recommendations and am trying to use this as an alternate approach. I am also trying to run different set points through this approach to see how it impacts predicted peak load.

Mark Eatherton

Interesting conversation here amongst professionals. Passionate professionals I might add. Having met with most al of the major contributors to this conversation, I can state without a doubt that they are all part of a larger brain trust of hydronic contractors. I see everyones point, and respect them as well.

Robert is using his time proven formula to double check appropriate sizing, based on previous experience. My experiences tell me that although close, there are a LOT of variables that are tough to take completely into consideration.

Rich and John have valid points as well. AHJ's don't accept historic fuel consumption records as a proven means of appliance sizing. Too many variables. Besides, as was pointed out, very few of these bureaucrats even understand what it is that they are looking at anyway. And as was noted, field enforcement is a WHOLE nuther issue... Our job of educating the AHJ will also never end...

Bear in mind that I am the person who constantly points out that even when we do a good and diligent HLC, and system design, when design condition comes around, and I see my "properly sized" equipment doing a 50% duty cycle, it tells me that the "real time" load is either half of what I'd calculated, or the equipment is 2 times larger than need be. You pick... Having been in the expert witness box many times, a diligent contractor is NOT going to cut the boilers or emitters in half based on a gut feeling. Only someone who is as crazy as myself (or Rich, or Hatt, or John, or Robert or a few others) would do that, and then only in my own home. Never in a customers home. It goes to the "assumed liability" that none of us can afford. If the load calc say 100, don't put in a 50, even though it will most probably work just fine, because if it doesn't (infiltration wild card), and you show up in court with a calc that say 100, and you only put in 50, it's not going to end well regardless.

My concern with the gross fuel consumption analysis is that it doesn't compensate for the electrical consumption occurring within the same dwelling. Assuming that there are no large external consumers of electricity (yard light, heated shop/garage, swimming/spa pool pumps etc) that each and every watt of electricity equals 3 btu's, 99% of which appears in the form of heat, regardless of original intent... It adds up pretty quickly.

My personal experience is more from a larger apartment complex profile. I did look at their annual fuel consumptions (gas and electric). But I also went a step further, and placed data loggers on the heating system, and also monitored the run time of the gas valve in "real time". I confirmed input and output of the appliance. The building doesn't have to go to "design condition" in order to get an accurate picture. It just has to be below 50 degrees, preferably at night. By monitoring the OSA temps, ISA temps, S&R temps, you can "see" the loads occurring in real time. You can also see the DHW (if it is a part of the boilers load) and its effect on loading, This real time consumption information was then extrapolated to "design conditions". You can also see the solar influence during a nice sunny day. Pretty amazing what that, and night sky re-radiation do to a conventional heat loss in real time. I actually developed a night sky re-radiation sensor that would tell me when the sky was clear or if the sky was cloudy. Generally speaking, we always find that the DHW load exceeds the space heating demand, and if the hydronic source is doing both, it obviously has to be sized to handle the largest connected load. Experience tells me that residentially, the exact opposite is true 90% of the time. (exception being the woman with the 4 man, one woman olympic sized bath tub that bathes nightly...)

As it pertains to the base temperature, my opinion is that the early building scientist had to start somewhere, and that number seems to make sense. Or does it...

My home in the mountains is a prime example. I can monitor that buildings energy consumption to the nth degree. I have a lot of PC's running internally, controlling the house and providing video monitoring etc. My homes "neutral" point is around 40 degrees F. In other words, until the OSA drops below 40, and there is no solar gain, the home doesn't lose ground temperature wise. And when we show up, and start turning on lights, ovens an using other appliances, that neutral point drops even lower.

I am certain that many contractors are looking at this conversation and saying "Oh sure, it's easy for him to do that because he has all those data loggers and stuff. but what about us poor guys that can't afford those niceties..." Well bunky, good news is that you too can afford to do this, and as Rich pointed out, YOU GET TO CHARGE FOR THESE PROFESSIONAL SERVICES" What a concept. A profitable company. Honestly, it will cost less than $1,000 to get all the data loggers you need to do these real time evals. And you will recover those costs at the second job you do with them if you charge appropriately.

Another item that really sets my hair on fire is the lack of noted influence that internal isolated mass has on the overall energy consumption figure, and this is not going to be an easy one to nail down. I am not aware of ANY North American H/L calculation programs that takes this into consideration, and it's net "real time" influence on heating requirements is HUGE... Enough so that commercial buildings are now installing hydronic radiant systems for base conditioning the mass in buildings. They "get" its influence, but have yet to figure it into the calculations. Some of THE lowest energy consuming residential buildings in the US were built to commercial specifications (steel deck panning, 6" concrete radiant floors, twin tee ceilings, etc) and are blowing even the established energy experts away with their miniscule energy consumptions.

Yes, it does come at a significant cost, but instead of chasing infiltration (which is necessary BTW to maintain good internal environmental health) maybe we should be looking at phase change materials, strategically placed in interior walls to help contribute to the loads. Maybe even something as simple as placing 1 gallon jugs of water into the internal wall stud space to add mass to the mix...

One thing I have learned in my 30+ years of doing this, is that the more I learn, the more I find that I need to learn to make sense of it all... Education and learning go hand in hand, and neither will ever end.

Thanks to all for the contributions. I'm still learning.

ME

Robert O'Brien

BoilOver said:

Really enjoyed reading that article. One question: given a design temp of 0 and a base temp for hdd of 65, why do you multiply gas usage/hdd/24 by 70 and not 65?



I have an Adobe home and am getting a variety of boiler size recommendations and am trying to use this as an alternate approach. I am also trying to run different set points through this approach to see how it impacts predicted peak load.

Typo,Sorry!!

Leon82

I did my heat loss this way and using the baseboard length was able to come up with a design day water temp. I am running about 5to 10 deg below that temp currently

Robert O'Brien

Mark Eatherton said:

Interesting conversation here amongst professionals. Passionate professionals I might add. Having met with most al of the major contributors to this conversation, I can state without a doubt that they are all part of a larger brain trust of hydronic contractors. I see everyones point, and respect them as well.

Robert is using his time proven formula to double check appropriate sizing, based on previous experience. My experiences tell me that although close, there are a LOT of variables that are tough to take completely into consideration.

Rich and John have valid points as well. AHJ's don't accept historic fuel consumption records as a proven means of appliance sizing. Too many variables. Besides, as was pointed out, very few of these bureaucrats even understand what it is that they are looking at anyway. And as was noted, field enforcement is a WHOLE nuther issue... Our job of educating the AHJ will also never end...

Bear in mind that I am the person who constantly points out that even when we do a good and diligent HLC, and system design, when design condition comes around, and I see my "properly sized" equipment doing a 50% duty cycle, it tells me that the "real time" load is either half of what I'd calculated, or the equipment is 2 times larger than need be. You pick... Having been in the expert witness box many times, a diligent contractor is NOT going to cut the boilers or emitters in half based on a gut feeling. Only someone who is as crazy as myself (or Rich, or Hatt, or John, or Robert or a few others) would do that, and then only in my own home. Never in a customers home. It goes to the "assumed liability" that none of us can afford. If the load calc say 100, don't put in a 50, even though it will most probably work just fine, because if it doesn't (infiltration wild card), and you show up in court with a calc that say 100, and you only put in 50, it's not going to end well regardless.

My concern with the gross fuel consumption analysis is that it doesn't compensate for the electrical consumption occurring within the same dwelling. Assuming that there are no large external consumers of electricity (yard light, heated shop/garage, swimming/spa pool pumps etc) that each and every watt of electricity equals 3 btu's, 99% of which appears in the form of heat, regardless of original intent... It adds up pretty quickly.

My personal experience is more from a larger apartment complex profile. I did look at their annual fuel consumptions (gas and electric). But I also went a step further, and placed data loggers on the heating system, and also monitored the run time of the gas valve in "real time". I confirmed input and output of the appliance. The building doesn't have to go to "design condition" in order to get an accurate picture. It just has to be below 50 degrees, preferably at night. By monitoring the OSA temps, ISA temps, S&R temps, you can "see" the loads occurring in real time. You can also see the DHW (if it is a part of the boilers load) and its effect on loading, This real time consumption information was then extrapolated to "design conditions". You can also see the solar influence during a nice sunny day. Pretty amazing what that, and night sky re-radiation do to a conventional heat loss in real time. I actually developed a night sky re-radiation sensor that would tell me when the sky was clear or if the sky was cloudy. Generally speaking, we always find that the DHW load exceeds the space heating demand, and if the hydronic source is doing both, it obviously has to be sized to handle the largest connected load. Experience tells me that residentially, the exact opposite is true 90% of the time. (exception being the woman with the 4 man, one woman olympic sized bath tub that bathes nightly...)

As it pertains to the base temperature, my opinion is that the early building scientist had to start somewhere, and that number seems to make sense. Or does it...

My home in the mountains is a prime example. I can monitor that buildings energy consumption to the nth degree. I have a lot of PC's running internally, controlling the house and providing video monitoring etc. My homes "neutral" point is around 40 degrees F. In other words, until the OSA drops below 40, and there is no solar gain, the home doesn't lose ground temperature wise. And when we show up, and start turning on lights, ovens an using other appliances, that neutral point drops even lower.

I am certain that many contractors are looking at this conversation and saying "Oh sure, it's easy for him to do that because he has all those data loggers and stuff. but what about us poor guys that can't afford those niceties..." Well bunky, good news is that you too can afford to do this, and as Rich pointed out, YOU GET TO CHARGE FOR THESE PROFESSIONAL SERVICES" What a concept. A profitable company. Honestly, it will cost less than $1,000 to get all the data loggers you need to do these real time evals. And you will recover those costs at the second job you do with them if you charge appropriately.

Another item that really sets my hair on fire is the lack of noted influence that internal isolated mass has on the overall energy consumption figure, and this is not going to be an easy one to nail down. I am not aware of ANY North American H/L calculation programs that takes this into consideration, and it's net "real time" influence on heating requirements is HUGE... Enough so that commercial buildings are now installing hydronic radiant systems for base conditioning the mass in buildings. They "get" its influence, but have yet to figure it into the calculations. Some of THE lowest energy consuming residential buildings in the US were built to commercial specifications (steel deck panning, 6" concrete radiant floors, twin tee ceilings, etc) and are blowing even the established energy experts away with their miniscule energy consumptions.

Yes, it does come at a significant cost, but instead of chasing infiltration (which is necessary BTW to maintain good internal environmental health) maybe we should be looking at phase change materials, strategically placed in interior walls to help contribute to the loads. Maybe even something as simple as placing 1 gallon jugs of water into the internal wall stud space to add mass to the mix...

One thing I have learned in my 30+ years of doing this, is that the more I learn, the more I find that I need to learn to make sense of it all... Education and learning go hand in hand, and neither will ever end.

Thanks to all for the contributions. I'm still learning.

ME

Mark, wouldn't a calculated heat loss ignore the contributions of heat generated by electrical appliances? How much precision is needed in a residential heat loss? A popular boiler manufacturer has 4 sizes of 85% AFUE CI gas boilers. 51,77,102 and 128 DOE. Do you need a sniper scope when the only weapon you have is shotgun? The gaps between those sizes are the entire heat loss of a smaller home! Not to mention, the smallest is still too large for the majority of homes. I look forward to your column in Contractor every month, always good stuff!

Gordy

I love Marks post. I did not quote it. However my favorite part is the influence of thermal mass in a structure, and how it Carries through the valleys in a structures heat loss. As noted when properly sized equipment is running at 50% duty. Some, but not all of that is the padding of the program. No one likes that call even the program designer.

Maybe a program drop menu for the designer living on the edge is in order. Bare bones no padding aside run at your own risk.

I suppose thermal mass, and its effect is hard to nail a %, or number for a program. Given the wide variety of materials that fill a structure from concrete to wood, and everything in between. From the structure itself to its contents all matter, and have effect. A variable with high influence is what we can call it to date.

BoilOver

Thanks for your reply, I just was trying to figure out if I needed to multiply by the (desired inside temp - design temp) or (desired inside temp - temp at which no additional heat is needed). In my case it's a little trickier because I suspect that high fifties, low sixties is a more reasonable base temp.

Mark Eatherton

Mark, wouldn't a calculated heat loss ignore the contributions of heat generated by electrical appliances? How much precision is needed in a residential heat loss? A popular boiler manufacturer has 4 sizes of 85% AFUE CI gas boilers. 51,77,102 and 128 DOE. Do you need a sniper scope when the only weapon you have is shotgun? The gaps between those sizes are the entire heat loss of a smaller home! Not to mention, the smallest is still too large for the majority of homes. I look forward to your column in Contractor every month, always good stuff!


Thanks for the kudos Bob, and congrats on your article. I like your style. As Dan told me, Write like you talk. You do. I can hear your voice when I read your writing You and Mike Rowe...

Back to your question, actually there WAS a time that the GSHP industry did take those contributions in to consideration, because it reduced the need for their systems. Talk about having minimum equipment that is typically oversized.And no, it's (addition of the electrical consumption btu's to a calculated load) really not necessary.

My point with that comment is that those are heating btu's, and should be added to the heating systems fuel consumption BTU's for the gross heating value. You wouldn't derate it like you did with the AFUE, but the btu's should be added into the hourly. Sniper scoping would be requiring the occupants thermal output to the mix

That limitation of the atmospheric boiler is why I haven't sold anything less than a mod con for the last, what, 20 years? Maybe our government will get its act together and eliminate that rediculous sizing issue... Should have done it about 15 years ago.

Anyway, thanks for reading me and thanks for your contribution to the industry.

ME

4Johnpipe

To quote a friend..."measure with a micrometer, mark with a piece of chalk and cut with an ax"...or something like that

lchmb

so..let me get this straight...the method of how many fingers covers the building from the street=how many sections the boiler will have doesnt work anymore? Dam...guess I'll have to do something different...

BobC

Better add one more section - just to be safe.

Bob

Gordy

No just take two more steps back that will do the trick.

njtommy

As a test lest see what you guys came up with for your own homes. I really curious to see what the heat loss by usage numbers are VS your own heat loss calculation.

As I said before my heat loss is 45kish at zero out for air temp. When I did the heat loss by usage last year I think I came up with 38k.

Leon82

With the slant fin app mine was 42k. With usage it was 35k.

Probably 30k because I used the bill with the most usage and was renovating a bathroom which had no ceiling.

It worked out to 145 or 150 average water temp at 7 deg with the math.
I set it to 145 in the odr and the house was comfortable.

Mark Eatherton

My load said 100K, I put in 100K of emitters, but only 50K of heat source. Snug as a bug in a rug, even BELOW design conditions.


ME