Hello there, i have been looking into geothermal heating for a new shop we are constructing. It is 50x100feet, and to the top is about 29'. We already have one build and are heating it by electricity and natural gas but that becomes pretty expensive. I am wondering how big of heat pump would i need? and how long of trench in heavy clay soil would i need also ( just an estimate ) I got plenty of space to dig trenches, and would like to do it vertical slinky if i could. I think geothermal would be a much better way of heating this shop, and would save us tons of money. We live in Saskatchewan canada, and in the winter it can dip to -45C, im not so concerned about air conditioning because the way we insulate these shops they stay fairly cool during the summer ( 10C difference from outside ). Thanks!

Hard to know what capacity is needed without wall and ceiling / roof insulation details. -45*C is a brutal design temperature, and it justifies massive investment in insulation.

Welcome! You need a heatloss with design temperatures and insulation numbers. You also need to consider air intrusion. What temp do you want to heat the shop to?

We just did a 50x100' shop designed to 63 degrees at 0 degrees outside temp, and in Buffalo, NY it turned out to be 72 KBTU with good insulation, about a 5 ton system. How much does you current shop use? For horizontal slinkies, we use 100' of trench per ton for the loopfield. Depends on your soil conductivity. Is the clay dry?

This is for ballpark only. You need some professional help designing your system, giving your high spikes of extreme colds. May be a hybrid system is the most economical solution.

Lows that low suggest northern Saskatchewan, so ground temps may also be very low, complicating loop design.

May we suggest an investment in luggage and a moving van?

Well on average the temperature through winter is -20C usually , but there are weeks that are way lower too. Our clay soil is wet clay, not dry, and our current heater in our shop is 70,000 BTU. This keeps its a really nice temperature. about 20C, which is where id like to see our new shop at too. We arent in northern saskatchewan, more southern actually.

We will probably use some good insulation, i know in our shop now we used R12 i think, and the way it is, is the walls are steel ( this is a culvert shed ) so there is a foot between the inside steel wall and the inside insulation wood wall. We also used 1/2" osb board to cover the insulation.



this is what our current one looks like




And sorry, i'd love to invest in luggage but, i'd like to set kids of my own up for a good yard and house someday on our land haha

Nat gas can be hard to beat - it allows lots of extra btus for a quick warmup after a setback (I assume that the shop could be kept much cooler at night). It also allows partial radiant (overhead tubes) heating - heat the people, not the air. Definitely use lots of insulation and air sealing.

Yea, but I've never seen a geothermal heat pump blow up a home or business like gas can. And you don't need CO detectors either with geothermal. And you can't say you are green. Other than that, you are right. It is hard to compete with gas.

Nat gas burned onsite for heat is quite arguably greener than electrically powered geo if the electricity was generated by coal fired power plants

blow up...

Yes, but geothermal uses 240V power - that dangerous stuff kills lots of people every year. :-)

Also, depending on setbacks (highly effective in a workplace), amount of directed radiant heat, power plant efficiency and ground temp, geo and nat gas can be equivalently green.

Posted By jonr on 30 Dec 2010 10:07 AM
Yes, but geothermal uses 240V power - that dangerous stuff kills lots of people every year. :-)

I don't recall an occasion where I accompanied the death of people with a smiley face.......

I don't recall an occasion where anyone so grossly misinterpreted what a smiley face applied to. But leave it to Joe@AMI Contracting to not have anything on subject to say.