Tell me that a DIY GSHP to reduce summer temp in the shed won't work and/or is a terrible idea!

[Will2442]

Hi all, new here and looking for some perspective.

 

I am thinking of a digging in a microbore copper ground loop (under the shed I am building) which is fed directly from the compressor (so no heat exchanger or pump) and powered by solar from the shed roof area.  The idea is to create a GSHP to bring the temp down during summer when there is lots of solar generating opportunity.  The shed will be insulated with 50mm PIR in the walls and 100mm in the floor and ceiling. I have never done anything with heat pumps or HVAC before so I would be making it up as I go along and it will be spectacularly DIY and not at all cost effective.  But its interesting and I think GHSPs are cool, I would consider even a couple of degrees of heat reduction as a success.

I do have a 16A feed to the garden so can use that if solar is not sufficient. The floor area is 4m x 2m and I estimate the copper loop will be ~50m.

 

The only reason I am asking and not experimenting is that I just had this idea but am due to finish the shed base soon and need to decide if I should at least put the copper whilst I can.

 

So - could this work?

 

 

Edited Tuesday at 10:21 by Will2442

[markc]

Hi and welcome. What are you thinking of pumping around the tube? I will be building a new man cave soon and been looking at GS heating and cooling but that’s using air drawn through a 100m long 100-150mm diameter tube.

microbore tube doesn’t have a lot of surface area for heat transfer

[JohnMo]

1 hour ago, Will2442 said:

microbore copper ground loop

Why not UFH pipe? Way more surface area for heat transfer. Micro bore will be rubbish, just too small.

 

Not sure it will be effective, the ground array will just be too small unless you are going vertical a long way down.

[Will2442]

1 hour ago, markc said:

Hi and welcome. What are you thinking of pumping around the tube? I will be building a new man cave soon and been looking at GS heating and cooling but that’s using air drawn through a 100m long 100-150mm diameter tube.

microbore tube doesn’t have a lot of surface area for heat transfer

Some kind of refrigerant? Its basically a fridge with the radiator in the ground at this point

[Will2442]

36 minutes ago, JohnMo said:

Why not UFH pipe? Way more surface area for heat transfer. Micro bore will be rubbish, just too small.

 

Not sure it will be effective, the ground array will just be too small unless you are going vertical a long way down.

Only because copper has great heat transfer properties and the microbore is flexible rather than trying to solder joints.  Could I put refrigerant in UFH pipe?  If not, I'd need a heat exchanger I think

[Beau]

I cant see that lowering your floor temp to say 15C is going to make much difference to the air temp

 

 

[SteamyTea]

While I like this idea, and had a similar one for heating my fishpond, it may be better to just find ways to stop the energy getting into the shed.

PV on the roof will reduce the input, as will a mirror.