Sugar Shack Heat

[pzoeller]

Hello all,

I've been lurking on here for a while and trying to learn as much as possible but I'm looking for some input on heating a sugar shack that I can't find an answer to.

We are still in the planning stages for a new shack. The main area is 30'x30' with two 26'x26' wings, one enclosed and heated for processing and one covered for the storage tanks.

I've been pushing for in floor heat since it would make clean up nice and dry fast, be stable at a low temperature set point (nov-mar when no one is in there) and having worked in a hangar with heated floors it's very nice to work on. However, it's expensive and going from 150 taps to 5000 taps in a season isn't cheap.

My father (and business partner) is leaning to electric baseboards. While they are certainly economical to install, I'm very concerned about the operating costs long term in Ontario.

We've tossed around ductless mini splits with baseboard backup, forced air propane (propane evaporator too so lots of gas around), hydronic baseboards etc. but we aren't getting any closer to a decision. I've got a local heating/cooling guy working on a quote for a few different options but nothing back yet.

Any input on heating the sugar shack would be much appreciated. Actually, any input on the design would be welcomed

Thanks,

Phillip

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[maple flats]

First of all, welcome!
I used to be in the heating business (outside wood fired hot water stoves). I would discourage electric baseboard because of issues when you hose down the floor and you will want to hose it regularly. Hydronic baseboard, maybe. Propane fired forced air, good choice. I put in a few in floor heats, they were nice but as you say, more pricey than some other choices. Since it will be a commercial type building some of the wall mount hydronic convectors might be a good choice too. I'm not familiar with "mini splits", please define. Of all those choices in floor heat will be by far the nicest.
happy planning.

[PerryFamily]

I heat my Ro room with radiant heat in the concrete that is heated by as oil fired hot water heater. It works awesome, was relatively inexpensive and I have hot water at every tank to clean. Cheap on fuel too. I'm sure you could size one for the building. my buddy is in heating equipment sales and install so he handled that.

[pzoeller]

First of all, welcome!
I used to be in the heating business (outside wood fired hot water stoves). I would discourage electric baseboard because of issues when you hose down the floor and you will want to hose it regularly. Hydronic baseboard, maybe. Propane fired forced air, good choice. I put in a few in floor heats, they were nice but as you say, more pricey than some other choices. Since it will be a commercial type building some of the wall mount hydronic convectors might be a good choice too. I'm not familiar with "mini splits", please define. Of all those choices in floor heat will be by far the nicest.
happy planning.

Thank you for the welcoming!

That's a very valid point about the baseboards that I should have realized myself since I am also trying to figure out how to best waterproof the walls. Doh.

A ductless mini split is a fancy heat pump basically. Rather than running a big heat exchanger in the plenum of the furnace though, it has small units mounted in multiple locations allowing for zonal heating. I.e. The r.o. room could be kept at a different temp than the evap room which could be different than the canning room. However, the efficiency drops off quickly at lower outside temperatures and around -20C (0F) they won't work so supplemental heat would be required.

Are there any known issues with forced air moving to much dust around or having issues with the replacement air inlets for the burners on the evaporator?

[pzoeller]

I heat my Ro room with radiant heat in the concrete that is heated by as oil fired hot water heater. It works awesome, was relatively inexpensive and I have hot water at every tank to clean. Cheap on fuel too. I'm sure you could size one for the building. my buddy is in heating equipment sales and install so he handled that.

So you are using a domestic hot water heater to heat the slab rather than a dedicated boiler? That was my first idea but everyone I've talked to around here has essentially spit on the idea but no-one has been able to give me a good reason yet other than that's just not how they do it.....which I'm not sure is a good enough reason....but I'm all ears.

[GeneralStark]

Hot water heaters can be used for radiant supply assuming the slab is well insulated and the building is well insulated. For larger square footage areas like yours it gets difficult to meet the demand (especially if you have r-18 walls as you suggested on sugarbushinfo) with a domestic hot water heater alone. It can also be done with an on-demand style heater.

Once again, my opinion is that you should put your money into air sealing, insulation and good windows+doors so you can more easily and effectively heat the space. Sure you are not trying to heat this place like you would a residence but just throwing heat into a poorly insulated space, especially in your climate, is a real waste of money in the long run.

[BreezyHill]

The key to a hot water heater as a heat source is the capacity of the tubing in gallons vs the capacity of the heater at 75 degrees. This is figuring you will be running the floor at the standard 70-72. We have a small tool room that is heated by radiant and is a great spot to pull in a tractor or snowmobile and thaw them out in the winter time. The room is well insulated as is the heated slab area. The issue is the doors that are only steel and have the air space to dissipate all the humidity that we produce thawing snow in cased equipment. Temp in the room is usually around 60 with the slab at 70. On a sub zero morning you can see the fog escaping the top area of the door joint, open the door and a cloud of fog rushes out. Near us there were two warehouse that were around 30,000 sq ft and heated with a single propane hot water heater with one as standby. owner told me it worked great and very cost affective way to heat that size area and keep the heat near the floor.

Zoning the tubing and double and even triple tubing space density in front of outside doors is another key. I got a book from a plumber friend and followed it for my design and same with our kitchen and it has worked very well. Kitchen is connected to the outside wood furnace and uses valving to adjust temp. I would like to find an electric camper hot water heater for the next project of an anti room. Hook the heater to the pc and install one of the new temp forecast programs to control the heat with respect to outside current and future temp. They ramp the temp up and have better use of the variable flow circ pumps that are available.

Good insulation installation is a good investment and pays for itself over time with a constant return in the future on the investment.

Good Luck!

Ben

[pzoeller]

Hot water heaters can be used for radiant supply assuming the slab is well insulated and the building is well insulated. For larger square footage areas like yours it gets difficult to meet the demand (especially if you have r-18 walls as you suggested on sugarbushinfo) with a domestic hot water heater alone. It can also be done with an on-demand style heater.

Once again, my opinion is that you should put your money into air sealing, insulation and good windows+doors so you can more easily and effectively heat the space. Sure you are not trying to heat this place like you would a residence but just throwing heat into a poorly insulated space, especially in your climate, is a real waste of money in the long run.

Thank you for your input. I wasn't sure how much cross traffic there is between the two forums so I posted on both. Hopefully that isn't against the unwritten rules of forum protocol. I'll be happy to take one down if there is too much duplication between them.

As a faithful subscriber to Fine Homebuilding magazine, I'm familiar with the push towards high insulation and tight buildings to lower the demand for heating (and cooling). At least in theory I am without much hands on experience with the specific techniques.

Most residential housing in this area is still built with an R18 wall, even in this climate. That is the standard still. What would you recommend for a target R value for the walls? 2" of XPS on the exterior wall would bring it closer to R28 with less thermal bridging. Of course just insulating the walls better is pointless without equivalent increase to attic and floor insulation.

We are mostly likely going with triple pane windows but I'm unable to source triple pane doors locally. I was also looking for the overhead door to have windows in it. Does anyone have any energy efficient options?

Thanks,

Phillip

[pzoeller]

The key to a hot water heater as a heat source is the capacity of the tubing in gallons vs the capacity of the heater at 75 degrees. This is figuring you will be running the floor at the standard 70-72. We have a small tool room that is heated by radiant and is a great spot to pull in a tractor or snowmobile and thaw them out in the winter time. The room is well insulated as is the heated slab area. The issue is the doors that are only steel and have the air space to dissipate all the humidity that we produce thawing snow in cased equipment. Temp in the room is usually around 60 with the slab at 70. On a sub zero morning you can see the fog escaping the top area of the door joint, open the door and a cloud of fog rushes out. Near us there were two warehouse that were around 30,000 sq ft and heated with a single propane hot water heater with one as standby. owner told me it worked great and very cost affective way to heat that size area and keep the heat near the floor.

Zoning the tubing and double and even triple tubing space density in front of outside doors is another key. I got a book from a plumber friend and followed it for my design and same with our kitchen and it has worked very well. Kitchen is connected to the outside wood furnace and uses valving to adjust temp. I would like to find an electric camper hot water heater for the next project of an anti room. Hook the heater to the pc and install one of the new temp forecast programs to control the heat with respect to outside current and future temp. They ramp the temp up and have better use of the variable flow circ pumps that are available.

Good insulation installation is a good investment and pays for itself over time with a constant return in the future on the investment.

Good Luck!

Ben

Your first example of the machine shop having moisture problems brings up a concern I have.

If a lot of time is spent air sealing and insulating to have a very tight building, won't moisture become a large problem? During syrup season, there must be a large amount of vapour in the air even with a steam-away, something that wouldn't be a concern in a house design obviously. Would a dehumidifier or HRV then be required to combat mold problems?

Has anyone ever come across a calculation of cost of insulation vs payback time? If payback is 3-5 years it's a very different business plan than if it is 25-30 years. I'm not knowledgeable enough to figure out the heat loss calculations and energy costs but there must be a guideline or rule of thumb available?

Thanks again for all the feedback,

Phillip

[GeneralStark]

The cost of payback will depend upon many factors. In a sugarhouse you are not going to be heating the space as you would a residence, although perhaps the processing room at times? Any decent heating contractor should be able to model the heating demand at a desired indoor temperature and give you a sense of what will make the most sense at different insulation R-Values and at different window and door R and U-values.

In terms of moisture issues, this is certainly something to consider and with the shift towards heated sugarhouses being relatively recent, I'm not sure how people are handling that, if at all. It seems like most conventional construction is still not dealing with it well, hence all the issues we hear about. I just finished building a super insulated/airtight passive solar home and we installed an HRV. I think this would be totally overkill in a sugarhouse, especially when most of the moisture is being generated in a month during weather which is often conducive to opening doors and windows.

[BreezyHill]

on moisture issue there are a few things to think about.

Temperature inversion is general in radiant floor construction so moisture is in the warmer lower air; so one can build a simple vent system of a 3" and 4" metal exhaust pipe to exchange air from outside. If you use a small enough fan on the 4" pipe the inlet on the 3" the exhausting air will warm the incoming air to reduce the affect of energy lose.

Insulate door is recommended so you don't have frosting on the door but the door handle will often have a coat on sub zero mornings.

[PerryFamily]

So you are using a domestic hot water heater to heat the slab rather than a dedicated boiler? That was my first idea but everyone I've talked to around here has essentially spit on the idea but no-one has been able to give me a good reason yet other than that's just not how they do it.....which I'm not sure is a good enough reason....but I'm all ears.

So here's my situation
My RO room is relatively small at 8 x 12
2x4 walls that are foam insulated
2x6 rafters that are foam insulted
Slab is 6" thick with 2" blue board under the floor
3 sides of the slab edges are insulated as well with blue board
The door is a simple solid core interior door that I had left over from my house
The heat source is a Bock oil fired domestic hot water heater
The floor tubing is heated with a system 2000 plate heat exchanger (3"x8"x 1" thick??)
That is run with a standard heat circulator
There is also glycol in the radiant to help prevent freezing
The domestic side has a stainless steel circulator which circulated the hot water through the heat exchanger
I set the heat as 45-48 in October ish , I fill the 55 gallon fuel tank and I won't fill it again until May or June
Plus I have hot water plumbed with pex to my Raw sap tank, RO wash tank, feed tank and several hose bibs for washing.

There's some other pieces plumbed in there too which I don't know what they are

It's really effective and efficient

Hope this helps

[pzoeller]

The cost of payback will depend upon many factors. In a sugarhouse you are not going to be heating the space as you would a residence, although perhaps the processing room at times? Any decent heating contractor should be able to model the heating demand at a desired indoor temperature and give you a sense of what will make the most sense at different insulation R-Values and at different window and door R and U-values.

In terms of moisture issues, this is certainly something to consider and with the shift towards heated sugarhouses being relatively recent, I'm not sure how people are handling that, if at all. It seems like most conventional construction is still not dealing with it well, hence all the issues we hear about. I just finished building a super insulated/airtight passive solar home and we installed an HRV. I think this would be totally overkill in a sugarhouse, especially when most of the moisture is being generated in a month during weather which is often conducive to opening doors and windows.

The assumption I made (and we all know where that leads....) was that the building would be kept around 8C (mid 40's) most of the winter and only warmed up if we are planning to do some bottling and for sugar season. Recovery time won't be an issue as we should be able to plan at least a day or two in advance.

My current HVAC contractor, which I've used for a few other small contracts, is an excellent "tin basher" but when I ask about heat load calculations I'm met by a blank stare. I think I'll ask around for some recommendations on someone else.

The general contractor we will be using is well respected and, for our area, fairly leading edge. He agrees with the sentiment that there are problems to be had with some of the newer airtight building techniques.

I my very limited sugaring experience, half the season is lovely and open doors and windows will be welcomed and moisture will not be a problem. However, the other half the season are cool, damp days where the shack will be mostly closed up and moisture levels will be high already.

Would a good HVAC contractor be the best person to talk to in regards to dealing with moisture?

We spent most of the 2016 season touring other operations in hopes of answering this (and many, many other) questions. Unfortunately, we found that in many cases there had been little consideration given to moisture concerns. As mentioned, the fully heated sugar shacks seem to be a fairly recent development.

Regards

[pzoeller]

on moisture issue there are a few things to think about.

Temperature inversion is general in radiant floor construction so moisture is in the warmer lower air; so one can build a simple vent system of a 3" and 4" metal exhaust pipe to exchange air from outside. If you use a small enough fan on the 4" pipe the inlet on the 3" the exhausting air will warm the incoming air to reduce the affect of energy lose.

Insulate door is recommended so you don't have frosting on the door but the door handle will often have a coat on sub zero mornings.

I'm a little confused. Do you suggest mounting a 3" duct with fan, inside of a 4" duct to create a simple heat exchanger? How would you seal it off when I aren't boiling and don't need the fresh air?

I'll have to talk to the inspector for the replacement air for the propane burner to see how it would affect replacement air for the burner.

Certainly we will be using an insulated overhead door. I'm curious if there are any insulated doors with decent energy efficiency ratings (dual pane windows perhaps? Extra sealing at the many joints etc.)

Thanks

[pzoeller]

So here's my situation
My RO room is relatively small at 8 x 12
2x4 walls that are foam insulated
2x6 rafters that are foam insulted
Slab is 6" thick with 2" blue board under the floor
3 sides of the slab edges are insulated as well with blue board
The door is a simple solid core interior door that I had left over from my house
The heat source is a Bock oil fired domestic hot water heater
The floor tubing is heated with a system 2000 plate heat exchanger (3"x8"x 1" thick??)
That is run with a standard heat circulator
There is also glycol in the radiant to help prevent freezing
The domestic side has a stainless steel circulator which circulated the hot water through the heat exchanger
I set the heat as 45-48 in October ish , I fill the 55 gallon fuel tank and I won't fill it again until May or June
Plus I have hot water plumbed with pex to my Raw sap tank, RO wash tank, feed tank and several hose bibs for washing.

There's some other pieces plumbed in there too which I don't know what they are

It's really effective and efficient

Hope this helps

Thank you for that info.

That was my original idea just writ large. I'm happy to hear it's working for you.

I would of course have to make sure that the water heater (be it a boiler or domestic heater) is sized large enough to handle the demand.

Thanks

[PerryFamily]

Thank you for that info.

That was my original idea just writ large. I'm happy to hear it's working for you.

I would of course have to make sure that the water heater (be it a boiler or domestic heater) is sized large enough to handle the demand.

Thanks

Yes for sure

The nice part about radiant is the heat is super even. It's also low to the floor, where you are working. Who cares what the temp is at the ceiling, it's nice and comfortable where you are. It also dries the floor from snow or washing or whatever. It's pretty nice

Good luck and keep us posted