I am planning a new building to start very soon. I am having trouble with a heat load or loss calculation. I have tried to use a online calculator, but I am having trouble with figuring out the correct information to put into the various feilds. Does anyone know of a source that explains how to do these calculations? Or have any ideas on how to learn about this?

Is the problem that you don't know about the design parameters and construction details of the new building or that you don't know how to put that information into the calculator?

If you posted the location of the calculator, there are a number of people here that might pitch in to help get it working for you.

There is a pro-level heat loss tool freebie, downloadable from Taco, the hydronic-heating hardware company.  In the hands of a newbie there are several ways to screw it up though.  The default outside design temps for locations in that tool are WAY below the ACCA 99th percentile outside design temperatures, and the default ventilation rates are also quite high (enter 0 if you plan to build a tight house).

This type of tool uses primarily an ACCA Manual-J type calc to add up the heat transfer through the various building surfaces & materials at  the indoor and outside design temperatures entered, using the steady-state U-values and total surface area.  (U-values are units of BTU per hour per square foot per degree-F difference between the cold & hot sides. The relationship to R values is R=1/U.)  The U values for insulated walls and roofs, etc are calculated from the "whole-wall" R values that consider the thermal bridging of the framing through the insulation. With windows & doors enter the labeled-U-value, or use a default of U0.5 for a 2" exterior wood door.  Some pro-tools do a pretty good job of modeling the mass effect of concrete or CMU walls, and have pretty good fudge-factors for air infiltration etc, but most are pretty crude. The result is that most will overshoot measured reality by ~15-35% (I've yet to see a heating-designers heat load tool undershoot measured performance.) 

U-values of windows are also usually overstated by 5-10% since the rating assumes wind-washing of the air-film adjacent to the exterior glass, a condition that rarely occurs at design conditions (usually the pre-dawn hours of a cold clear night), and average performance is measurable better than rated performance.

In a new designs it's more educational & useful to use a energy use somewhat more sophisticated modeling tools like BeOpt or DOE2 for optimizing the design, which also gets you to a total heat load number.  These tools do a better job of figuring in solar gains and modeling thermal mass effects than most heat-loss tools.  When you know the costs of different constructions you can then play "what-if" with the modeled building, to decide which modifications or upgrades to the design have the best net-present-value, etc.

Thanks for the replys. I have a set of plans and for the most part I know how I am going to build it. So I guess most of the problem is how to input the info and I dont even know how to find the design tempertures and which calculator to use. I was trying rescheck. I am building In Sierraville, ca 96126. Its a shop building with hydronic slab on grade. Probably 2" under slab and perimiter insulation. The shop is 44'x32'x12' with sissor truss roof. The walls will be buit with Raycore sip pannels R-40. I am thinking about fiberglass batts in the ceiling with ridged foam on the bottom of the bottom cord. I dont know how thick it should be or if it is a good idea or not.

Posted By stealman on 06 Apr 2012 10:47 AM
Thanks for the replys. I have a set of plans and for the most part I know how I am going to build it. So I guess most of the problem is how to input the info and I dont even know how to find the design tempertures and which calculator to use. I was trying rescheck. I am building In Sierraville, ca 96126. Its a shop building with hydronic slab on grade. Probably 2" under slab and perimiter insulation. The shop is 44'x32'x12' with sissor truss roof. The walls will be buit with Raycore sip pannels R-40. I am thinking about fiberglass batts in the ceiling with ridged foam on the bottom of the bottom cord. I dont know how thick it should be or if it is a good idea or not.

If you're not on the gas-grid and using propane or an electric boiler you may want to go higher-R on the slab foam.

At Sierraville's summertime temps fiberglass isn't a great choice in the ceiling due to it's translucent to deep infra-red, and the insulation 1-2" below the top surface will end up being signficantly hotter than the attic-space air.  Unless you went with more-expensive high-density batts the wintertime performance would also suffer from convective loss of R at the temperature extremes unless you also put a top-side air-barrier over it to keep attic-air from convecting freely with the batts.  If the truss chords can handle the dead-load, a blown cellulose solution would be more effective, both winter and summer. If the pitch of the scissor-chord it very steep you may have to use wet-sprayed cellulose to keep it from sloughing toward the soffits over time.

Rigid foam under the truss chords is fine, but it's usually cheaper to just add another R10 in blown insulation OVER the truss chords to get the same amount of thermal break.

If you look at the 99th percentile outside design temperatures  you'll find that the 99the percentile design temp is 0F, even though it gets colder than that a few nights, some years. You can compare that to weather data sources to verify, if there's a weather station near you.

If it's a rectangular building you have roughly 1800' of R40 wall area (less windows & doors), and 1400' of roof.  Assuming a 70F interior and 0F design temp that's a delta-T of 70F.  R40 SIPs have a U-value of (1/40=) 0.025, so the heat loss out walls is going to be roughly:

1800' x 70F x 0.025BTU/ft²/degree-F= 3200 BTU/hr.

If you load up the trusses with 12" of cellulose and put an inch of iso under the truss chords the ceiling would be roughly R50 or U0.02. So the roof losses would be:

1400' x 70F x 0.02= ~2000 BTU/hr.

If you have 10 windows at 10 square feet per, (100 square feet total ) with a U-value of 0.30, your window losses would be:

100' x 70F x 0.30=  2100 BTU/hr.

If you have more like 20 windows, double that to 4200 BTU/hr.

That's only 8300BTU/hr of conducted losses at design temp.

SIPs can be made pretty tight, especially if you spray-foam seal the connection to the ceilng and detail the ceiling as an air barrier, so you count the air-infiltration as essentially zero under most conditions, but for yuks lets just double the conducted losses, and then some- still not a very big heating load.

I suspect your AC load will be substantially higher than your heating load unless you control summertime solar gains fairly carefully, by design. With your average winter temps being higher than 25F, even if you're on the gas grid you might want to consider both heating and cooling the place with a high efficiency ductless heat pump (mini-split) rather than a hydronic slab.  You'd still want to put at least 1.5" of XPS or or 2" of EPS under the slab (Add 1" to 1.5" for radiant).  There are many 1.5- 2 ton mini-splits would still deliver over 15KBTU/hr @ 0F.  (eg: Mitsubishi MUZ-FE18NA, nominally 1.5 tons, which can still deliver over 13KBTU/hr  of heating @ -10F , and ~25K of cooling.)  A 1.5 ton typically runs $4-4.5K, a 2 ton $5-5.5K, installed.

Thanks for the help and ideas. We dont have natural gas and our elect rates are kind of high. So propane will most likely be the heat source. I would ultimately like to use a gasification wood boiler and or some solar hot water in the heat system. Why would you not suggest hydronic floor. I would really like to have that warm floor feeling. I assume it is the install cost? I would like to pay for a professional design ( still dont know who to use for that) and install myself.

Posted By stealman on 06 Apr 2012 04:04 PM
Thanks for the help and ideas. We dont have natural gas and our elect rates are kind of high. So propane will most likely be the heat source. I would ultimately like to use a gasification wood boiler and or some solar hot water in the heat system. Why would you not suggest hydronic floor. I would really like to have that warm floor feeling. I assume it is the install cost? I would like to pay for a professional design ( still dont know who to use for that) and install myself.

It's not the installation cost per-se, but the combined systems cost of separate heating and cooling systems.  If you're on propane the heating cost will be on the order of 2-3x+ that of a high-efficiency mini-split too. 

Heating with a ductless with 12-cent electricity in your neighborhood costs about as much as heating with natural gas at a buck a therm, so it's pretty much a wash compared to natural gas. If your electricity is more like 18cents and gas is cheaper than a buck there's no argument- heating with gas is the way  to go. But at the current  ~$3/gallon propane and 12 cent electricity it's more than 3x the cost of heating with a mini-split with a seasonal average coefficient performance of ~2.5 (which is about where it would run in your local climate).  If your electricity is more like 18 cents it's only 2x as expensive to heat with propane as with a mini-split, but still... it's TWICE the operating cost, and you'd still be on the hook for a separate system for cooling.

I like the feeling of warm floors too, but on an R40 building with 1400' of radiant floor an a design heat load of under 10,000 BTU/hr the floor isn't exactly warm except during design conditions.  Say it's  even 14KBTU/hr @ 0F. With 1400' of floor that's 10BTU/ft, which means the floor needs to run about 5F above room temp. In a 68F room, that's 73F- warm enough to notice.  But at 30F outdoor temps it's about half the heat load, and your floor temps would only needs to be ~70F to keep it 68F in there, the floor is not cold but no super-cozy either.  In a shop building you're probably not cruisin'  in yer socks either.

Daikin makes a high-efficiency air-source to-hydronic heat pump that could heat your slab just fine, but it's on the order of 3x the cost of a mini-split, and has more design considerations to take care of. Mini-splits are "systems in a can", all of the engineering is done,  with very little other consideration necessary for the site beyond heating & cooling loads and the performance at the anticipated outdoor temps. With air-to-water the pumping rates and water temps etc have to be designed a bit more carefully to get the efficiency out of it.  You could still cool with it in chilled-slab mode if your cooling loads aren't very high, but it won't dehumidify. Summertime dew points in your area are low enough that floor condensation isn't very likely going with a chilled slab (unlike the eastern seaboard of the US, or the gulf coast.)

The Net Zero Energy home designers are all over mini-splits for moderately high-R buildings like this, since they have similar efficiency to ground source heat pumps in somewhat warmer areas, if a bit lower for you. Your seasonal average heating COP will be about 2.5, whereas on the CA coast you'd be into the 3s, (much like geo/ground-source when all pumping and air handler power is factored in.)  But for the difference in up-front system cost between geo & mini-splits you can buy a photovoltaic system that produces more than the difference in annual electricity use.

My electric rate is .144 per kwh. I am not familiar with the ductless minisplit. I have heard about them and that is about it. Can I get a even heat with this type of heater? Would I use more than one to achieve even heat?
This building has a high ceiling and that is another reason I wanted hydronic, so all the heat does not go to the ridge. I was not planning for air conditioning to cool. I don't really think I need it. The nights are always cool. I don't think many people around here have air conditioning. I moved here last fall, I was living in Lake Tahoe and almost no houses there have air cond and I never wanted one.
I'm not sure how this plays into it, but I will probably keep the thermostat pretty low and use a wood burning stove to bring the temp up to a more comfortable level. This is assuming I don't get a wood fired boiler which looks like it might not make financial sense.
I appreciate your help and mostly just want a efficient and comfortable building. This building is a shop, but I plan to live in it for a while before I build the house.

Posted By stealman on 06 Apr 2012 10:37 PM
My electric rate is .144 per kwh. I am not familiar with the ductless minisplit. I have heard about them and that is about it. Can I get a even heat with this type of heater? Would I use more than one to achieve even heat?
This building has a high ceiling and that is another reason I wanted hydronic, so all the heat does not go to the ridge. I was not planning for air conditioning to cool. I don't really think I need it. The nights are always cool. I don't think many people around here have air conditioning. I moved here last fall, I was living in Lake Tahoe and almost no houses there have air cond and I never wanted one.
I'm not sure how this plays into it, but I will probably keep the thermostat pretty low and use a wood burning stove to bring the temp up to a more comfortable level. This is assuming I don't get a wood fired boiler which looks like it might not make financial sense.
I appreciate your help and mostly just want a efficient and comfortable building. This building is a shop, but I plan to live in it for a while before I build the house.

At 14.4 cents/ kwh & seasonal COP of 2.5,  100,000TU of heat delivered to the building with the mini-split costs $1.69.

With $3/gallon propane burned in a 95% AFUE boiler, the same 100,000BTU of heat delivered to the building costs $3.47.

Unless you're planning on heating the place only to 50F with the propane and are cutting your own wood, you could leave the place at-temp 24/7 with the ductless and be money ahead compared to a propane fired solution.

A wood boiler would be a better bet for running the hydronic slab, but heating with bulk fuel gets old fast, and it's not always cheaper.  It will usually cheaper than the ductless when its 10F outside, when the ductless is only pulling a COP of ~2.  When its 45F or warmer outside the mini-split will have a COP of 4+, delivering that 100,000 BTU for a buck or less.

If you set up the mini-split to run at the desired temp and crank up a woodstove or wood boiler, the mini-split backs off as the load drops, and will turn off completely if you raise the temp above the set point, then starts running again when the temp drops.  Since they work more-efficiently at low compressor speed it's usually more efficient to "set and forget"- the lower efficiency of a recovery ramp uses more power than running them at lower compressor speed keeping the temp constant. But since they also run more efficiently at higher temp,  one strategy is to fire up the woodstove for the overnight taking the load off the mini-split during the less-efficient temps.  This works pretty well for residential applications- I'm not sure what your use-schedule is on the workshop.  If it's going to be idle for more than 12 hours/day it may have a different economic, but would likely still be cheaper than propane.

In open floor plan buildings a mini-split heats pretty evenly. The blower runs constantly, but it's speed varies with the load.  In a high-R building with an open floor plan you probably won't see more than a 1-2F difference from one end of the building to the other even at the outside design temp.  On a moderately high-R residential project I've been advising on, in a ~800 square foot 3-bedroom apartment with the mini-split head in the open living/dining/kitchen space, the exhaust intake registers for the heat recovery ventilation system are placed in the bedrooms & bathrooms only, to help even-out the room-to-room temperature differences (modeled to be about 3-4F cooler in the bedrooms at outside design temp if the bedroom doors are always closed, but the performance has yet to be verified, as it's still under construction.)  The heat loss out of those rooms is well bounded but similar to your building (1 window per room, R40 whole-wall R, U0.18 windows.)  Keeping the common space at 70F would keep the bedrooms above 65F at design condition with the doors closed, warmer with the doors open.

You make a good case for a minisplit. What about the high ceiling and the mini split. I have been told that with floor heat the heat stays low. With a minisplit I assume the heat will go to the ceiling. I have 12" plate hight and 16' ridge.

A mini-split air-to-air heat pump can be a very efficient heating and cooling source if properly applied. Short of multi-head models they are generally a one room appliance. Multi-heads are available but the price of system goes up dramatically. I have a single head at the top a three story staircase in my own radiated home.

Everybody wants radiant floor heating. This is especially true if you have any windows in your house. Unless you are super-insulated with triple pane glass, there is no comparing radiant floors and forced air of any flavor. As for wood boilers; here in the Minneapolis area, we can still buy wood (split and stacked) cheaper than off-peak electric, oil, propane or natural gas for that matter.

We design radiant floor heating systems using Wrightsoft with the Uponor module (among others). We also design and install radiant floor heating systems using wood, oil, gas, coal and electric. Solar space heating if rarely effective unless you are in a near desert climate. http://www.badgerboilerservice.com/images/SampleHeatLoadAnalysis.pdf


DIY heat loads are usually the first mistake and can be a hard one to fix.

Posted By stealman on 09 Apr 2012 10:40 PM
You make a good case for a minisplit. What about the high ceiling and the mini split. I have been told that with floor heat the heat stays low. With a minisplit I assume the heat will go to the ceiling. I have 12" plate hight and 16' ridge.

Mini-split  heads run the blower nearly continuously, mixing the room air for near-zero stratification of the room air.   Radiant floors in a tall building will also have very low stratification, but the radiant floor also heats the ceiling surface via direct radiation.  The deal with radiant is that it heats the humans directly for that nice "cat sitting in the warm sun spot" effect when the slab is well above room-air temp, whereas with mini-splits it's heating the air.  But because it keeps that air moving (however slowly, at low load), the temp near the ceiling is still going about the same as it is 1-2' off the floor.  Only if you had  abyssmally crummy windows creating a large heat loss near the floor would the ceiling be appreciably warmer than where the humans sit.

To be sure, at identical room temps the radiant would be appreciably more comfortable, especially on the colder days.  But you can make up a lot in general comfort in general comfort by raising the room air 2-3 degrees, and still have plenty of cash left over for a nice pair of slippers if you're not heating the slab.  The cost difference is still going to be ~2:1 for heating condensing propane vs. a high efficiency ductless, even if you're running it a bit warmer for comfort with the latter.  I love radiant too (have radiant zones in my own house), but I wouldn't pay $500-1000 per year extra for it.  In most markets natural gas is cheaper than (or similar to) the cost of heating with mini-splits, in which case the radiant comfort might win out. But with oil or propane as the heating fuel, if the heat load at design condition is within the capacity of a ductless heat pump it's usually not even close.

If  there is a wood boiler is in your future it may make sense to put the PEX in the slab, but there's not much rationale for a propane burner here.  In a much colder climate or if you had a much higher anticipated heat load mini-splits might not have the capacity at low temp (and the average efficiency would be lower), but you have both the mere moderate-cold climate and low heat load going for you.

One of those rare cases where I beg to differ...with Dana.

If you are moving air, you will have stratification. This is particularly true of rooms with high ceilings.

Radiant floor will have similarly low temperatures at floor and ceiling, unlike any forced air system where higher temperatures at the ceiling are inevitable raising heat loss and lowering comfort at once.

If the head of the mini-split is within a foot of the highest ceiling - as in my own case, it will do a superior job of cooling if used for a single open room, but heating space for comfort benefits in no way from moving air except to make up for inferior technology...much like raising the temperature on the thermostat.

Good economics but not the ideal space heating system.

I bow from the waist. hehehehehee

And yet...

In my uncle's 2- story the mini-split head is mounted about mid-way on the full 2-story (~19', IIRC) great room, and both heats & cools the first & second floors without perceptible stratification. He sets the louvers to direct the air downward in the heating season and lets convection deal with the rest, and conversely in the cooling season. Clearly YMMV, but in an open shop building like this I don't see it as an issue in the same way that it is in multi-story homes, and homes with doored-off areas.

The wind-chill effect of any air-based system is a detraction from comfort in heating mode, sometimes a boost to comfort in cooling mode. But with the variable speed blowers on a ductless it's not nearly as obnoxious as sitting in the stream of tepid-air geo systems or oversized bang/bang ducted AC. It's not as toasty-roasty as sitting in front of the register of a scorched-air fossil-fired hot air furnace either. By design the air temps relative to velocity/chill are pretty comfortable, since the original target market for them was (cramped by US standards) Japanese & Korean houses & apartments, where you would not be able to avoid the air stream. You won't want to park it over your kitchen table if you want to read the newspaper there (unless you read the paper on your Nook or Kindle :-) ), but it shouldn't be hard to find reasonable placement in an open shop building.

Using a Daikin Altherma to heat the slab would be closer to the ideal in this location and would cost the same or less to run as a mini-split, but the up-front cost is pretty substantial. Still, a decade of heating with propane would be more expensive on combined system + operating cost than an Altherma. With a mini-split the upfront costs are a wash compared to a condensing-propane water heater hydronic system, and you're money ahead in the first heating season.

'like it DANA1  !


Lynn Perkins was ~ 82 in 1994

I traveled with him we sold AMWAY a dozen of Lynn's  VERTICAL AIR STABILIZERS

VASCO was vertical air stabilization corp to him

He had me report on JC Penny stores and IRS Dayton use
40w
6" fan
reduced to PATENTED nozzle design like a jet nozzle in some instances,
not much different than a HOSE BUD-TIP for stream... EFFECT on the air
like hydro-Plane boats racing changed from hydrodynamic foils to WEDGES in for steering better at high velocities, VASCO had wedge-vane shapes in (HIGH) 2200 fps velocity out of the 4" nozzle, and even a cross-shape wedge leaving side of only ~5/32 width on the trailing edge, worked nicely
AirThrow:
33 ft
Destabilized 28 ft ceilingswithin 2-deg diff

variable SCR controller so hot on 8 ft applications to get down to 3 ft above floor
velocity of only 2 FPSec to hit floor

(unit drop, hitting blades internally , prop stopped as the UL Listed motor mounts melted enough in the plastic studs ...)

Li'l suck-buckets RESULTS were In though:

17 % saved in cooling JC Penny
and 23 % heating...
periodic cleaning required
One every 20-25 ft apart, maximum density

Some were right above workers on roller-bed line in Col PANIC Dist, by the delivery doors opening all winter:
Saved and lowere Unit heater settings in cold warehouse, workers toes warmed...

So I went to BEDE Cleveland, with their hassock TURBO-AIRE in mid 80's and turned their pic upside down:
JETSTREEM 50 was printed...
80 watts threw air 55 ft !
-sold a bout 200 all together-

The latest out in the market is 60+ ft unit ( I hope irt got the COMM UL LISTING, or the electricians wont touch it ).

Hose-Button-Head technology is copied from other naturally created organic designs for air or water fluid dynamics...

Then the registers in basements were finned-inward, like the the hose-bud, or button positioning, sufficient to get low streem vertical air stabilization downward (VASD)
Now customers don't wrap on blankets in basement-rec-room seating... !

A wall register 18x30 (noisy at that end) 3800 cfm with 4-way fins 2-inner sets out 5-deg, outers turned inward 3 deg, threw air nearly 70-ft and completely conditions 23 ft ceil in office warehouse, aisle allowing blast, to far end,  not any duct , 70x55 room,
HIGH return airs 11 ft ...

VASD technology distributes a low layer of warmer air to cause the convection turn-over you mentioned out about 8-12ft from central airstreem ( similarly opposite the pond-bubbler effect )

a 6x10 register 4-way can sufficiently destratify a stairwell if open to bottom 25 ft high, standard ~ 150 cfm

KEEP 8ft away from walls to 12 ft away: Vertical Air takes care of itself in cooling ,  not over , but by people...
Where applicable:
Do NOT WASH WALLS nor WINDOWS laminate air sticking to surfaces, which is that - that is acting like a layer of thin insulation.


...

Captain Badger:

Just what I tested this last early March:::
18-22 degree days, :::

If you put in radiant low mass floor heating in vaulted 13000 sqft house, GT or IBC Boiler assisted...  you WILL get stratification of about 9-degrees usually, I have found in high glass-wall ratios over 40%, especially...

I proved that to the IBC installer/distributor...

I turned on the GT air in a Radiant application, and we all watched the RETURN air sensors climb in 3 minutes to 79 in 70 -degrees, and drop in thenext 20 minutes to 2 deg over room temp.
Running up to the  stair way ~ 9ft off vault, the platform was still76 degree, kithchen a warm 73, rest of house 72

all RADIANT heating with stratification:

Please experiment with vertical air destratification, and tell us the BTUh per sq ft...

We are commonly below 11 btuh per sq ft, in destratifien homes, 2 story, under 2.1/2 deg from user-space to user space a story below ( 6" off of a flat ceiling,  20% below the vault areas  .

Lynn Perkins showed me this with a 10-ft golf-reach pole extended with a thermal probe (RED LED THEN !).

When the sun came out on those 20-deg days, the stratification shot higher to over12-deg, without the low cfm "FAN-ON" recirculation...
NOTE: Registers and air distribution is critically custom adjusted, for turbid, but not felt air movements. (Hah! Non-Sensed Savings)

Note: Grocery stores Engineers told me they completely destratified stores with only 2.3 air-volume-changes through blower systems... in the 80's. I treid to sell'em the JetStreem 50 VASD technology.

We use usable volume desired to move: divided by 17 to get CFM. A quick check on systems with average glass to wall, and not much solar spotting in a small space, relatively.

Much depends on construction. Residential and commercial system cannot be usefully compared. Large glass will through off all temperatures but creature comfort is best delivered with high AUST. ODR will keep most radiant floors and ceilings within a few degrees of each other in most residential construction with glass at 40% or below.

Hello Member Stealman : (oh: Lynn P was training me then on vertical air distribution in 1984, not 1994)---
What of a lifestyle
of the shop might entail is things like machining with oily air- mist, ot something to sawdust...?
(my presumptions of 'a shop') Needing any air-cleaning and related ventilation?
We all see finned air coils are rated at a dry-cleaned condition~

What's it really for in the air quality?Really good hydronics are installed with pumps/simple controls here in OH over 11 bucks/SqFt
BUT REM THE TAX CREDITS if they apply...
Are you using a small HW Tank? A/C? and Heating, all together? Your low heating requirement with hydronics may qualify with a tiny solar and gt -for cooling size , central contract for HVAC+HW+all ventilation, inclusive.

Propane is great in always only needing a peanut generator to remain above freezing in power outage, but what if that is not an issue? Would spot-electric zoning either overhead-air coils or in-floor electric mats or radiant electric panels be simpler ( over all the years, even coming out of this 9-year all time-low gas pricing, propane and maintenance has not much to offer over spot-electric if your truly at 5-7 KWH LOADS full dark-night, -10 below, some winds blowing )

Because I do compare usefully Res and Comm applications, this is not a problem, -jus'whatIdo..

-Would be happy to Load calc, fill in sq ft form (click logo) www.GEOPros.org add notes of heat-radiation or motors running. Motors are interesting, loaded in spec ranges, (not variable) they CAN at times run cooler in all processing, as work done to remove material or lift things is subtracted from electrical energy used leaving heat !
I worked in metals machining starting as 'maintenance' while cutter-grinding and lathe...

The nation and Ohio today in (Energy Transfer) GeoThermal Loop sizing to building loads, uses my same 2003 published loop calculations for heat transfer because the numbers were driven by PERFORMANCE GUARANTEED .
In your Defense:
You can buy calcs by websites that just as Captain Badger remarked, are driven by such that those calcs can be off (and Dana1 shows) by 30%.
But your loads are tiny enough that even a couple of P-Tac type GeoThermal units through-wall consoles, fresh air venting, and 1-each tiny GT loop borehole, and the 10% uncapped comm tax credit (? if "for profit") may be interesting- and if a little heat-recovery to Hot Water is "free" in Air Cooling.
HOWEVER

'nough said:

What's the lifestyle of your shop Member Stealman?
And Surface areas entered into form , and I see notes on wall, sq ft /glass/ I will calculate a bit differently for the other factors of radiant transmission and typical air losses in 5 years from now.
Cooling machinery?, a few People in the shop? Ventilation bringing in humidity?

~Today most ANY hydronic materials distributor or Manufacturer freely does a loss-calc, piping layout, etc.
KITEC in CAN, IPEX dist in USA, to slant-fin, all have quick acting assistance for possible sales. Since bought both, that's who I have further checked with, and other Pex co's distributors. Warm toes are cool!

BUT: Vertical Air distributed nicely effectually affects "FLOOR-RADIANT-LIKE" comfort more than adequately (( moving air about 2-3 ft per sec at knee height towards flooring)) where not standing under much...
---if a low fan speed from A/C system or unit moves air in winter heating, downward to flooring.
Insulate that slab well and find your toes are warm, and an electric mat (if applicable , below a stand-on mat used for health of the feet,etc)

Nice info Dan1 ( as you knew anyways!)
Captain Badger may have a great consideration depending on the shop use and ++ light energy and ++ interior equipment ++ solar-spot-on-floor gains, etc.

Pretty good to even see if you have a local Trane or York or Carrier HVAC bud with simply accurate A/C calcs ((your heat may take care of itself, comparatively, as Dana1 shows)).

Construction even with old 1-Ton per 350 sqft, ancient calcs: Heavy Comm Office,etc. loading: 4-ton a/c
But if only a horsepower of electrical radiation, and a 7- 8 ft "COOLING Ceiling" leaving air above 8ft undisturbed, ~ 40% of sq ft (roughly to discuss)
@ 400 cfm (380 better) per net compressor ton (rating of 2-ton may only have a 1.1/2-to-1.3/4 ton compressor, appearing ~ 340 cfm/"ton-rated"...)
About the 1.1/2 Ton plus equipment ~ radiating heat from 800 watts per "rated-ton" needs to be added, I believe, you would be at 2.1/2 rated tons, with some reasonable dehumidifying (open to criticism). Blasting air on high gets great efficiencies until dehumidification problems creep up.

IN THIS 'ART' and 'PRACTICE' that it is.. a lot is just well-covered with the variable staging systems, or simpler (less costly replacing) 2-staging compressors.
Your diffuser-register(s) fins adjustment can cause air flows to over 40-feet from a relatively acceptably-sounding outlet from a 4-way, adjusted /sized for velocity/ grill; and 25 ft throws are virtually silent.

DO seal a batt insulation with at least some cellulose blown-over ~ 4"' to 6" thick... Dana1 has pointed out in other pages radiation reasons, and may more specifically recommend more, as I have found since 1993 with commercial low BtuH and low-temp geothermal and solar additions.

Smallest compact Heating and Cooling and HW unit on a 30x30 footprint stands ~ 90" high over a stand over a 35-gal or 25 gal HW tank, does not need any buffer tank for hydronics, is putting a Hydro-Temp Corp (Arkansas) www.Hydro-Temp.com small 2-spd unit with Priority HW and a (if clean radiant with same domestic HW ..but usually not used) heat exchanger to radiant in floor. Used by HUD in AR "lowest cost invested in 7 years, over any other" has been said.
Filter Return grill on unit, Hot Water faster than a propane res heater, A/C to = necessary tonnage sized. Heats radiant high-mass (low temp) concrete really efficiently;and higher than today's top Air-Heat Pumps, all annual utilization inclusive: 30+ Year G-t Longevity, (clean/1/yr: vinegar rinse of 100% Instant HW) powder-coat black cabinet. PIC like Comm stand-alone on H-T website. HW tank can have internal HW Exchanger to radiant, easy solar / gas Hybridding.

ENERTECH Geo-Comfort/ TETCO/ HYDRON GT makers -claim same.