to many options not enough time

farmdaddy

1st post but prob not the last, depending.

one man show ATM with our farm shop, 7500sqf foot print, 2 story on 1/4
usable a bit over 8500.
My design has me at almost 7900sqf.
3 zones, after much playing and teaching myself loopcad over the last 3 days, adding my concrete footings for my steel side of it, it looks pretty good.
good temps, even better its not resi.
pretty happy with lay out, configuration based on all the other things I have to lay out, mechanical, plumbing, electrical... conduit channels on the apron side, 800 amp service, 5000sqf of solar panels, generator, well runs, out building service(s)... etc.
got it all pretty well narrowed out uniformly.

1.5" runs to zone manifolds heading in those zones.
because I like a little steampunk flavor I'am gonna tig up some copper manifolds, 2' has me pretty nice with 1/2" on 6" slab @12'
my shopping list had me round up mins, so all actual numbers are lower in spec.

I have my zones configured with 3 tankless (electric?) heaters.

1. Main shop floor, most use, big entry doors.
12 circuits
7gpm
70kbtu
peak 73.5k
head loss 10'
1/2' oxy pex at 12'
SWT 112
5000sqf
surface heat of 82

2. woodshop and mechanical rooms, big doors, lower celling less used space, mixed walls rooms.
9 circuits
3.5gpm
35k btu
peak 28k (load 33k)
head loss 10'
1/2" oxy pex at 12"
SWT 112
2200sqf
sruface heat of 80.9

3. main floor farm store, upstairs office
5 circuits
3.5gpm
35k btu
peak 30k btu
head loss 10
1/2' oxy pex at 12"
SWT 145
3400sqf
surface heat 79.9


looking for some advice on pumps and tankless heaters.
its like walking into walmart right now, giant warehouse of **** I dont want.

since we do generate solar and will generate a ton more, electric seems to be the best option. I can make electricity but cant make gas, my gen set is 200A and is NG,
so... I could run NG but thats not cost effective or off grid.

closed system, no heat exchanger, ill run a small tankless for potable hotwater.
1 shower and 4 or 5 sinks.

3 tankless heaters for the 3 zones
2x 35k
1x 70k

we live in NE oregon towards the coast range, 100% water.

most of the zones will sit idle at 60/65 a majority of the time, fall and winter we will tax it to comfortable.

I really want to make this a clean and simple install, mainly because I have to look at it.

I could mix zones automatically.. but really dont want to go down that rabbit hole.

id rather spend the money now, over regretting it later, might add a chiller in the future.

I only want to use one pump per zone, I know I could push/pull, not worried about noise.
heat efficiency and cycle are my main concerns.
having 3 or 4 40amp breakers for one zone makes me hate this.

any and all ideas are welcome..
would love some honest feedback and more, suggestions, my ears are open.

sold pumps and high efficiency heaters are #1, going down the rabbit hole researching the right parts is a whole lot harder than asking.

thanks.



.

psb75

Electric tankless water heaters are not the right devices for radiant floor. How about air to water heat pump?

hot_rod

A heat pump, either water to water or air to water would be my first choice. Modulating electric boilers next.
See if there are any programs here to offset costs

https://programs.dsireusa.org/system/program/or

farmdaddy

psb75 said:

Electric tankless water heaters are not the right devices for radiant floor. How about air to water heat pump?

hot_rod said:

A heat pump, either water to water or air to water would be my first choice. Modulating electric boilers next.
See if there are any programs here to offset costs

https://programs.dsireusa.org/system/program/or

Cost is always a concern, but time is another more pressing matter.
maybe I could back apply to off set cost, but if I didnt it wont stop me from buying the right thing over something cheaper.

ive seen systems work with tankless, that said efficiency is also from a gas system, not electric.

we have rodents out here... they like to get into heat pumps and mini split units.
we have 7 zones 2 condensers and a Sanden heat pump.
I F***ing hate it, 1890's farm house with a very expensive addition and full remodel in 2017. I wasn't here for it.
I was here to change the IPM board out in 2020 when a rat shorted out across a few 400v caps, burned the center out of the body and bulged the eyes out like balloons.
that also created a two year effect on other parts.
thats another story.

Id have much rather done a zoned central with the heat pump.. but all of it and frankly outdoor untis have just left a bad taste in my mouth

we will end up creating way more power then we can use, beyond storage and our 200amp generator.
so, if we lost all power my only pit fall would be the giant propane generator.

I cant make gas but I can make electricity multiple ways, why I don't want to do natural gas.

most of the zones in this build wont require heat for a majority of the year or much, the ones that do will have mini's, they are way more suitable for those to use, they are shared on radiant design to.
I use heat currently here 6 mos out of the year in my tiny 2000sqf shop with a pellet stove.
not insulated, absolute **** R... like maybe 1.
I run 80lbs of pellets @ 24hrs. when its really cold.

I am not opposed to running a heat pump, couple things though.
I want 3/4 independent zones, having one part kill everything is just not cost effective to me.

1 zone will have the ability to heat and cool its self. most insulated and probably the easiest.

2 zone is the shop, huge ceiling that slopes from 30' to 12', 80' clear span. essentially 50x80
its a shop, big giant doors. I am more concerned about the radiant heat making everything warm then it keeping a residential temperature. I have other means to mitigate that in the future.
if it held 62 degrees id be more then happy.

3 zone is a woods shop, 40x48 that will be drywalled and insulated, itll probably always be set at 50 unless I am doing a project, which ill know a head of time to ramp up. it also has two full size garage doors.

4 zone is my mech rooms, minimal layout in both and dont really need to be over 50 ever, most times theyll probably heat themselves.

what I dont want to do is over complicate it, also I want to have the ability to have a failure and make a quick change to compensate, maybe the room temp wont be what I want but it wont be freezing.

ive been in houses with giant, complicated systems (much older) that never did what they promised.
ive been in newer ones with instants that worked.
not gonna pretend to do this for a living, but one part of my company has had me involved in many aspects of these systems.

ive built and designed whole home LV systems for some time intergrading and seeing the innerworkings of a bunch of these systems.
that said, I also no when to say I dont know.

my thought process was really only demanding heat from one zone on the biggest unit and allowing the other zones to run pretty idle, for the other zones it would be the simplest and most cost effective route.
I could dial those units down to a pretty low number.
most of the spaces will see 1/10 the use of the shop.

I see the advantage of the heat pump, but I have zero advantage to having a dedicated heat source to each zone. unless I run 3 heat pumps.

why couldn't/shouldn't I use 3 nice tankless?
sorry for the long detailed explanation.

mattmia2

You have to do some math to figure out if solar with a heat pump is practical, if you can afford that much pv. solar thermal and a storage tank might be more practical. A ground source heat pump would solve your rodent problem.

mattmia2

a tankless isn't a boiler. if you do want to use electric resistance, use an electric boiler. It is unlikely you can generate enough power to run electric resistance heating.

farmdaddy

mattmia2 said:

a tankless isn't a boiler. if you do want to use electric resistance, use an electric boiler. It is unlikely you can generate enough power to run electric resistance heating.

yeah,
I an kinda at the part where my brain goes from science to magic.
ive been known to do both.

I have a couple of fears for sure, I also feel I can make changes to them on the fly on the inside.

I do know a tankless isnt a boiler, my math has me maxed at 75k with less R then actual, the building heat environment is mostly relevant to one room. the one at 75k (61k @nope) total output with storage and generator is like 3 large residential houses when done, while powering ours. this side of the property is getting 800amp service. (695) without our solar

my math was a little over 120kw, obviously based on unrealistic potential. that was solar max with existing solar.

neither answers offer a direct answer other then I doubt it, why?

I can find tankless with a good warranty that will do 13% over demand at a temperature way over my needs and will operate in max.
at 7gpm
trying to do math here @ under $1k and over $4k isnt adding up for me.
especially when

why/what? isnt that I CANT do?
before you answer, I personally would go a different route if I had to GC this for someone else for sure.

but Id ask both of you that have responded if you have any experience in doing this or if you are going from 1000s of successful installs not ever doing it?

still... with a giant UGH.
what is the best variable pump any pump?
I really appreciate all of this, thank you!

mattmia2

A tankles is controlled to heat domestic hot water. It is designed to heat 50 or so degree water 120 degrees or so and is turned on and off with a flow switch. Tankless water heaters typically have a lot of flow resistance.

An electric boiler is turned on through some sort of contact closure, from a thermostat or end switch on a zone valve or from a zone controller. It is designed to have inlet temp near the outlet temp and maintain a specific outlet temp. Tankless water heaters have trouble doing this and will sometimes shut down on errors when you attempt to use them like this and there is no definite way for the system to tell it to run.

GroundUp

This topic has been beaten to death for decades. Simply put, if a tankless water heater could replace a boiler, they wouldn't make boilers anymore. A boiler is always the correct appliance for this type of usage. With that said, I do a ton of electric boilers (and replace a ton of junk tankless water heaters that people tried to cheap out on the first time around) here in MN and if your load is indeed only 140k (which is doubtful), a pair of Electro EB-WX-23 boilers piped in parallel with an STG-5 staging controller would be the bees knees for this system. I just completed a similar system using two 18kw boilers for a 10 zone apartment building last week, and it's performing very well as they all do. You'd have 3 zone pumps and a primary/boiler pump, or one zone pump with 3 zone valves and still a primary/boiler pump to do this properly. The Electro units modulate and operate in stages based on the outlet temp and when paired with the staging controller, the second one may not even come on when it's not needed.

leonz

farmdaddy said:

1st post but prob not the last, depending.

one man show ATM with our farm shop, 7500sqf foot print, 2 story on 1/4
usable a bit over 8500.
My design has me at almost 7900sqf.
3 zones, after much playing and teaching myself loopcad over the last 3 days, adding my concrete footings for my steel side of it, it looks pretty good.
good temps, even better its not resi.
pretty happy with lay out, configuration based on all the other things I have to lay out, mechanical, plumbing, electrical... conduit channels on the apron side, 800 amp service, 5000sqf of solar panels, generator, well runs, out building service(s)... etc.
got it all pretty well narrowed out uniformly.

1.5" runs to zone manifolds heading in those zones.
because I like a little steampunk flavor I'am gonna tig up some copper manifolds, 2' has me pretty nice with 1/2" on 6" slab @12'
my shopping list had me round up mins, so all actual numbers are lower in spec.

I have my zones configured with 3 tankless (electric?) heaters.

1. Main shop floor, most use, big entry doors.
12 circuits
7gpm
70kbtu
peak 73.5k
head loss 10'
1/2' oxy pex at 12'
SWT 112
5000sqf
surface heat of 82

2. woodshop and mechanical rooms, big doors, lower celling less used space, mixed walls rooms.
9 circuits
3.5gpm
35k btu
peak 28k (load 33k)
head loss 10'
1/2" oxy pex at 12"
SWT 112
2200sqf
sruface heat of 80.9

3. main floor farm store, upstairs office
5 circuits
3.5gpm
35k btu
peak 30k btu
head loss 10
1/2' oxy pex at 12"
SWT 145
3400sqf
surface heat 79.9


looking for some advice on pumps and tankless heaters.
its like walking into walmart right now, giant warehouse of **** I dont want.

since we do generate solar and will generate a ton more, electric seems to be the best option. I can make electricity but cant make gas, my gen set is 200A and is NG,
so... I could run NG but thats not cost effective or off grid.

closed system, no heat exchanger, ill run a small tankless for potable hotwater.
1 shower and 4 or 5 sinks.

3 tankless heaters for the 3 zones
2x 35k
1x 70k

we live in NE oregon towards the coast range, 100% water.

most of the zones will sit idle at 60/65 a majority of the time, fall and winter we will tax it to comfortable.

I really want to make this a clean and simple install, mainly because I have to look at it.

I could mix zones automatically.. but really dont want to go down that rabbit hole.

id rather spend the money now, over regretting it later, might add a chiller in the future.

I only want to use one pump per zone, I know I could push/pull, not worried about noise.
heat efficiency and cycle are my main concerns.
having 3 or 4 40amp breakers for one zone makes me hate this.

any and all ideas are welcome..
would love some honest feedback and more, suggestions, my ears are open.

sold pumps and high efficiency heaters are #1, going down the rabbit hole researching the right parts is a whole lot harder than asking.

thanks.



.

=================================================================


It is your money; in my opinion you will be wasting it as you need the simplicity of one pipe steam heat.
Did you know that the entire Empire State Building is heated with less than 2 P.S.I.G. steam?

1. a properly sized heating system for a farm shop or industrial application does not win beauty contests

You need to determine the total cubic footage of the building you have to heat and go from there.

2. You have to build the shell of the building with properly insulated foundations, walls and ceilings on each floor to do the job of holding the heat in and heat it based on the total cubic feet that the building will have as you are also fighting dampness and need dehumidification

3. you need simplicity and very simple heating that can be operated by a small 110 volt generator in the event of a power loss by simply unplugging the boiler and plugging it into an extension cord connected to a small generator

3. As you will have foot traffic your customers expect you to have a warm building at the entrance and steam heat will give them that warmth at the floor level and help keep your floors drier

As this is going to be new construction an overhead steam heating system with a properly sized steam boiler with a double drop header and steel column radiators or cleaned and tested cast iron radiators from a building salvage dealer would heat the building at very low pressure using threaded pipe and only threaded pipe would be what I would do as you want steel pipe for close boiler piping.

Using a steam boiler lets you take advantage of the fact that one drop of water will expand 1,700 times to when boiling make steam heat.

Using a single drop header with two risers one size larger than the steam risers will let the wet steam expand and the water droplets fall out and travel to the header pipe and radiators much faster pushing the air out of the radiators and letting the steam in faster and holding the heat in the radiators longer.

Using a double drop header will provide dry steam even faster to your entire building and the dry steam heat will also heat the radiators much faster.

A properly sized central header pipe with the correct number of vents at the end and vents in each radiator in the top floor and first floor with vents in each radiator OR using TRV's to control the room temperature or simply reduce the building temperature when the building is unoccupied by turning down the single thermostat in the area that is occupied the most being the farm store turning it up 2 hours before it is to be occupied.

The farm store is going to need heat near the entrance and exit to help keep the floor dry and reduce the effect of cold wind gusts. Having a roof over the entrance will help with that.

A properly designed one pipe overhead steam system does not require a condensate return pipe to the boiler.

Cast iron radiators would be better as they have more mass to create more thermal mass for you.

Every time you open an overhead door you will lose massive amounts of heat from the heated floor that will take a long time to recover no matter how much tubing you put in a floor. Both overhead doors need to be insulated too.

Start with the total cubic foot volume of the building that you will need to heat before you put pencil to paper and then look at how much better steam heat is to use.

A long as the system is designed correctly it will cost you less over time and your ground floor and second floor will be warm and dry and the TRV will let you heat rooms at a minimum temperature without using a single circulator as the only power needed will be for the boiler-except for a thermostat controlled dry steam to forced air heater hanging in the ceiling where the garage doors are.

My thoughts on this anyway.

hot_rod

You should be able to heat most slab radiant with water below 100F. No need to force the phase change to steam 212F for a simple floor heating shop?

It takes a lot less energy to heat water to 100, compared to steam.

There is absolutely no substitute for warm concrete shop floors for comfort and efficiency.

Post pics of the TIG copper manifolds.

Dave Carpentier

" Every time you open an overhead door you will lose massive amounts of heat from the heated floor that will take a long time to recover no matter how much tubing you put in a floor. "

There's a thermal mass in the bare slab that helps, plus usually some air space above the height of the opening to trap some air. On ours anyhow, just opening and closing the overhead recovers in a reasonable amount of time.
What I've found to be very significant is bringing a frozen vehicle into the space. That just keeps eating the btus like a hungry monster.

leonz

That is one of the two reasons why I suggested the overhead steam heating as it woul dbe new construction and as there is no air lock door there to moderate the temperature or a leanto entrance covering the doors providing the building entrance on that side is away from the prevaling winds.

It would be different if both overhead doors were separated by a wall and were separate closed rooms.

One properly sized large steam to forced air heater may be more than enough to heat this garage area with dry steam heat.

hot_rod

Dave Carpentier said:

" Every time you open an overhead door you will lose massive amounts of heat from the heated floor that will take a long time to recover no matter how much tubing you put in a floor. "

There's a thermal mass in the bare slab that helps, plus usually some air space above the height of the opening to trap some air. On ours anyhow, just opening and closing the overhead recovers in a reasonable amount of time.
What I've found to be very significant is bringing a frozen vehicle into the space. That just keeps eating the btus like a hungry monster.

Actually if you have a concrete mass charged up it acts like a flywheel when you open and close the doors. That energy radiates from the slab at the speed of light and the cold air space widens the delta T so the floor output goes up. An 80F floor surface in 50F air space emits 60 BTU/ sq. ft.!

With a forced air system, once the hot air leaves, there is no flywheel storing heat, you start over packing the space with hot air.

As far as warming up that block of cold mass you brought into the space, it is a BTU exchange regardless of what heat distribution method.

Years ago Delta built a repair facility at the SLC airport. It was radiant floor heat. The "garage" door folded open wide enough to allow a 747 in.
All the engineers arrived for the first open door/ cold plane test. The results were probably in an ASHRAE journal back then.

Highly doubtful ceiling FA could warm that massive air space as quickly as that multi thousand pound floor flywheel sitting at 85F.

Also FA melts the snow from the top of the vehicle down, the radiant floors warm from below, so mechanics prefer the warm floor heat to FA unit heaters.

So examples of the heat storage capability of concrete.

leonz

For what its worth;
The surface shop at the mine where I used to work was large enough to store 3 front end loaders and a trackmobile that could move 12 covered hopper rail cars.
The single propane fired forced air heater heated it very well and the floors were warm.