Need Help on BTU Calc for my shop

[BHetrick10]

I have a 40 x 64 shop all with radiant in slab heat. The "Toy" side of the shop is 44 x 40 with 16' high ceilings 3 10 x 10 well insulated garage doors 2 man doors and 4 30" x 40" windows. The business side for storing material is 20 x 40 half of that space has 7' ceilings and the rest has 16'. There is one 10 x 10 well insulated garage door, one man door and two windows. Above the business side is space that I plan on finishing into a kitchen/ living room. It is 20 x 20 x 8'. It has one door and two windows. I will most likely heat this area with hot water base board. I have a room in the attic that I plan on making a bedroom and bath room. It is 24 x 18 x 8'. It has two windows and one door.

The garage currently isnt insulated but will have R19 in the walls and blown in up in the ceilings. I have 2" foam under the slab and 2" foam around the perimeter for a thermal break.

The space I am finishing to live in I plan to be able to heat to 75. The Toy and business side I am guessing on 55 normally and plan on using the hanging hot water fan forced heaters to raise the temp if I am out there working.

I want to be able to heat everything with 120* water because I have a Garn 2000 and want to get the longest possible burn time. I live in Central PA where I 'd guess winter temps to average high 20*.


I am looking at having 5 zones plus DHW. Toy, business, kit/Liv, Bed/Bath, Fan forced heaters.

I guess what I am getting at is a am trying to figure out if the 1" pex tubing is enough for the supply and return to the garn? It is I believe is no more than 60' from where the manifolds will be to the Garn.

Thanks in advance for the help.

 

[jebatty]

Looks like a real cool shop when you are done. There are numerous websites which identify the information needed and then calculate the heat loss for you. I used one of these sites when I determined the heat loss for my new shop. I planned for a worst case scenario, outside temps to -35F. Of course, that happens, but not often and not for long, and my heat loss, even during some -35F night time cold periods (it does warm up in the daytime), worked out to less than about 1/2 the calculated heat loss.

With your use of 1" tubing, you will have about 80,000 btuh available for all the things you want to do, and hopefully your heat loss calc + DHW demand will be less than that most of the time. Be sure to plan your zones and emitters to provide the btu's you want while using 120F water. You are wise to plan for 120F water, as the Garn will provide hours of heat between burns with usable water at 120F.

You also will need to do a pump head calculation, which normally is done at 20F delta-T, which means 8 gpm water flow rate. Your main 1" line will need a circulator that at 8 gpm will handle the calculated pump head. A rough guess-estimate is that the pump head over 120' plus fittings, etc., will be in the 7-10' range. And then each of your zones will have to share that 8 gpm/80,000 btuh, to provide each zone with the heat needed. Size zone circulators/valves accordingly, and be sure to balance your zone loads so that when needed each will get the btu's needed, or at least the priority zones will get the btu's they need if there is not enough to go around.

Your project is not overly complex, but since it appears that you are new at this, you also may want to consult a local professional to help you plan out your system and hopefully avoid costly and sometimes difficult or impossible to correct mistakes.

 

[Fred61]

I can't help you with your calcs but I can tell you that 120 °F water in a hanging fan forced heater (Modine) will feel like someone's blowing cold air on you.

 

[BHetrick10]

Fred I agree on the 120 in a modine. I figure most of the time I wont have them on and the radiant will be used the most.

I looked for different heat calc programs and the numbers were all over the place. Anywhere from 40,000 to 100,00+ I was hoping to get some insite from experts on here as I am not one.

If I figured right a 009 pump will get the job done? I do have what my be a problem though, my manifolds are about 6' higher than the top of the Garn.

As far as consulting a pro it seems like most of the guys I know are used to reg oiler boilers and not familiar with what to do about the garn being lower...