Two zone mini-split recommendations

[skykooler]

I am working on a slightly unusual project - a bus that only has living area in the front half and a machine shop in the back. For safety reasons, I am separating them with a reinforced steel partition, which introduces the question of how to keep the back area warm in the winter. I don't need it as warm as the living area, but need to make sure nothing freezes, and ideally keep metal surfaces from getting too cold to comfortably handle. I've been looking into mini-split ac/heat units, but not having much luck finding a multi-output one that's not way oversized. Any recommendations for this?

 

[Jolly Roger bus 223]

ok first tell us what you have as far as bus size length?
what the square footage of the garage is and the footage of the living space is.
what is your location.
there are several options available multi split systems with a single outdoor units.
cost and quality both come into play.
available space?
metal cold enough that you cant handle shouldnt even be worked with metal to hot to handle and work with? put your gloves on and get to work.

 

[Jolly Roger bus 223]

mitsubishi , daikin, LG, lenox , pioneer brand.
let us know what bus you have and i/we can get you in the right direction.
daikin likes the twin pipe system more than mitsubishi. and LG is aggrevating to get right control wise and lack of support. but that is my experience in dealing with bigger systems in commercial construction.
i am putting pioneer in my short bus but its only one indoor unit but i do know that they make a split indoor system but will it work for you

 

[skykooler]

I am still working on finding a bus but I am looking for a full size/11+ window bus. Just trying to plan ahead. As for square footage, roughly two thirds will be the garage vs a third for living space. I am currently in PA but looking at driving to Idaho or Montana some time after the conversion is finished. Not so worried about cooling the workshop area down as I am about keeping it from getting too cold in the winter.

 

[Jolly Roger bus 223]

many an option but its not as cheap as a huge battery bank to run said heat a/c or run a gennie.
they are a less power draw than a conventional rooftop or window unit but do you want to be stand alone? on a gennie full time? what do you want to run in your metal shop off of power?
what kind of metal work?
steamfitter/pipewelder by trade. grown up to VRF systems but still get to play in my steam rooms and steam plants but most buildings are going VRF.
google the idea and you will see the many options you have for your idea?
gonna take you into aa different realm until you narrow down what you want but will give you an idea and look at all manufacturers ideas and not just the first one that pops up with ducted ceiling cassettes. they all make two indoor wall hung units with a twin pipe connection or just tee off to the first unit on the way to the second.
it happens daily in my world.
no reason it can not happen in yours

 

[s2mikon]

If you just want heat I would recommended the Chinese diesel heaters. I have both mini split units and Chinese diesel heaters. The mini split units get used when it is not to cold due to heat pump efficiency. When it is real cold I like the Chinese diesel heaters much better. I also have a wood stove for free heat from wood.

 

[Jolly Roger bus 223]

a simple heater will do that on shore power or gennie.
if i dont gut my entire family camper to make it happen then my next bus build will be a full weld shop with a truck as a toad.
i already work outside for a living and if a building has heat or A/C working then i move to the next one that aint working.
metal to cold to work with or to hot to touch is not a thing as long as you know what you are working with.
never seen metal to cold work with? have seen steel covered in snow that welded just fine and was man handled and have handled the same pile in 100 degree sun with no problems.
either one wear your gloves.
i think you want your work are conditioned for you to work in and your living area of course at a different temp.
i want a full weld shop in a bus but all windows are deleted and covered when on road and dropped full open when working and an exhaust fan especially galvanized welding.
that is an idea in my life?
how old are you and what is your experince with metal?
i want a multiquip whisperwatt3500 capable of running two welders and 120 volt at the same time 2-3 auxilary tools like grinders porta bands?
in my idea of a mobile metal working/weld shop.
welder powers the bus when on site.

 

[skykooler]

many an option but its not as cheap as a huge battery bank to run said heat a/c or run a gennie.
they are a less power draw than a conventional rooftop or window unit but do you want to be stand alone? on a gennie full time? what do you want to run in your metal shop off of power?
what kind of metal work?

I intend to run stand-alone; I am planning on using a 2kW solar array on the roof and a battery which I have not sized yet. I mainly do machining but also some welding.

If you just want heat I would recommended the Chinese diesel heaters. I have both mini split units and Chinese diesel heaters. The mini split units get used when it is not to cold due to heat pump efficiency. When it is real cold I like the Chinese diesel heaters much better. I also have a wood stove for free heat from wood.

I would prefer to have an electric system rather than a diesel or propane system for multiple reasons.

a simple heater will do that on shore power or gennie.
if i dont gut my entire family camper to make it happen then my next bus build will be a full weld shop with a truck as a toad.
i already work outside for a living and if a building has heat or A/C working then i move to the next one that aint working.
metal to cold to work with or to hot to touch is not a thing as long as you know what you are working with.
never seen metal to cold work with? have seen steel covered in snow that welded just fine and was man handled and have handled the same pile in 100 degree sun with no problems.
either one wear your gloves.
i think you want your work are conditioned for you to work in and your living area of course at a different temp.
i want a full weld shop in a bus but all windows are deleted and covered when on road and dropped full open when working and an exhaust fan especially galvanized welding.
that is an idea in my life?
how old are you and what is your experince with metal?
i want a multiquip whisperwatt3500 capable of running two welders and 120 volt at the same time 2-3 auxilary tools like grinders porta bands?
in my idea of a mobile metal working/weld shop.
welder powers the bus when on site.

Gloves are fine for welding but I do a lot of machining work as well, for which gloves are a liability. I'm 28 and have been welding and working in a machine shop for six years. My goal is to try and set up a large enough solar system to be able to run the machine shop off-grid.

 

[joeblack5]

Nice idea, what kind of machining tools and sizes will you have in your bus.. what kind of jobs are you planning to do. Maybe better to run a dehumidifier.. throws of some heat because of the latent heat and reduces condensation on your equipment and stock. Some insulation will help also...you might want to consider a low floor citybus.. more standing hight for a mill. Some have larger windows that tilt up for better ventilation..larger separate doors to get in and out in the living and shop area.. not negotiating the stairs all the time and some of these busses are 6" wider.

Good luck
J

 

[ABBus]

I intend to run stand-alone; I am planning on using a 2kW solar array on the roof and a battery which I have not sized yet. I mainly do machining but also some welding.
.

It will not work. You"ll need the most power to heat up your bus when outside conditions are the worst (short days, low sun, etc. ...). Snowing? No power. On a usual winter day, you'll get 2kWh, maybe 3 if you're lucky. That's a continuous 100W load. Let's say my estimate is pessimistic and double it. 200W. Still very far away from the kind of power you would need.

 

[skykooler]

Nice idea, what kind of machining tools and sizes will you have in your bus.. what kind of jobs are you planning to do. Maybe better to run a dehumidifier.. throws of some heat because of the latent heat and reduces condensation on your equipment and stock. Some insulation will help also...you might want to consider a low floor citybus.. more standing hight for a mill. Some have larger windows that tilt up for better ventilation..larger separate doors to get in and out in the living and shop area.. not negotiating the stairs all the time and some of these busses are 6" wider.

Good luck
J

Current things I intend to have in that section are a lathe, mill, workbench with swappable inserts to convert to a table saw/router table/downdraft table, tool chest/cabinet, welding table, weld cart, and a 2x4' cnc mill/laser. I have all of these except the mill and cnc currently and have been working with them arranged in a 7' wide area of my shop to get a feel for how that layout will work in a bus.
A city bus is an interesting idea but they seem much harder to find. I'd also be somewhat concerned about the wheel arches which take up much more internal room than in a school bus.

It will not work. You"ll need the most power to heat up your bus when outside conditions are the worst (short days, low sun, etc. ...). Snowing? No power. On a usual winter day, you'll get 2kWh, maybe 3 if you're lucky. That's a continuous 100W load. Let's say my estimate is pessimistic and double it. 200W. Still very far away from the kind of power you would need.

That's definitely a concern. The areas I'm looking at don't get much snow in the winter, though it does get below freezing regularly. I'm also considering having an extra 1.5kW roll-out array that I store under the bus.

 

[HazMatt-SKO]

You're doing the old timey, traditional tinker one (or SEVERAL) better! Kewl!
I suspect that the minisplit is an electrically powered device, so my thought is to install one (or 2, depending on your personal and latitudinal requirements) small, ceramic heaters.
In my experience, they aren't huge amp hogs, and will keep your shop well above freezing (ceiling insulation dependent). Electric heat doesn't add to the interior moisture burden, either. Jusayin'. NOT a bad thing...
The reinforced partition should be decently insulated, so before you get in gear to get machining; open the intervening door(s), set a floor fan within the shop's entry blowing straight forward, and then proceed to relax, and savour a cup or three of coffee while the shop gits itself acclimatized and ambientized.
Thermal vagaries might require that pedal elevation above grade MAY be temporarily called for during said atmospheric handling procedure.
Tolerable temperature thresholds notwithstanding; after a goodly part of 2 decades living in New England, with it's attendant winter Nor'Easters, goin' 3 years now in Texas and I'm finding that 68°, while watching the sun set in shorts and a tee (Me. Not the ginormous glowing gasbag) to be approachingly chillingly.
I think I did alright, subjected as I recently was to a 24 hour/no power scene, all the while the overnight temps went negative.
In any event... your individual cubic-footage mileage may vary

 

[skykooler]

I suspect that the minisplit is an electrically powered device, so my thought is to install one (or 2, depending on your personal and latitudinal requirements) small, ceramic heaters.
In my experience, they aren't huge amp hogs, and will keep your shop well above freezing (ceiling insulation dependent). Electric heat doesn't add to the interior moisture burden, either. Jusayin'. NOT a bad thing...

As I understand it, the minisplit shouldn't contribute to interior moisture either, and should do about two to three times as much heating per watt as a space heater; which is the main reason I'm looking at them, to keep the heating power as low as possible.

 

[Tfanous]

Why not a diesel heater instead? From my understanding, mini splits are better at cooling than they are for heating. Diesel heaters are much more efficient and you can get very good quality ones that are safe and efficient and barely sip diesel, such as Espar by Eberspacher or Webasto.

 

[skykooler]

I'm avoiding diesel, propane etc, because I'm trying to reduce the amount of fossil fuel usage; the eventual plan is to convert the bus itself to an EV using two 100kWh battery packs from salvaged Teslas.


Also, I figure a mini-split is useful since it can both heat and cool and therefore save space that would otherwise be taken up by separate units.

 

[joeblack5]

Nice idea's.. if you know where you are going thenaybe lookup the amount of sunhours day you have in that area that will determine your amount of solar required for your shop needs.

For our bus Dory we need about 3kw non stop when the temps go below 30f with some wind. That is 65f inside.. so for a 10h night that is 30kwh.. with a mini split at a cop of 3 that would equate to 10kwh electric during the night only..

If you are driving everyday and can scavenge electricity from the alternator then it is best to drive at night so you have engine heat.

With more insulation and less windows and more sweaters it might go down to 5kwh for the 10h night but it is going to be a tough equation to solve....more sweaters is the cheapest.

Good luck, johan

 

[Sagzster]

Don't dual zone mini-splits only come in 220V?