gshp in florida ac only
 

i have read most of the heat pump manifesto and joined the site because of it
i am the installer for a solar pv and thermal company.

my soil temp is 70* from 2' to 6' didnot go farther
my plan was to retrofit my existing ac system with a refrigerant to water heat exchanger on the condenser side like this one
www .aquasystemsinc. com/models_test.html Aqua Systems efficient Liquid to Refrigerant Heat Exchangers there only $140 for the 2 ton unit. the owner is very helpfull and has some geo thermal experience
and connect a slinky loop field to the exchanger and cool the condenser
but now i plan on using a FHP 24,000btu geothermal heatpump (Florida Heat Pump)
my house is 1000 sq ft and i have a 2 ton ac unit and resistance heating

i have plenty of space for a slinky coil trench and maybe free access to a backhoe.

my plan is to dig down 6' where the soil is very moist and lay my slinky.

the heat exchanger guy gave me a figure of 100' of trench per ton with 400' of pipe in the 100' trench

i have also heard that 600 foot of pipe slinky will fit in 65' of trench im guessing tighter spacing.

i was thinking of diging 3 trenches around 80' long 3' wide and 6' deep
and putting in around 750' of pipe in each trench. i located 800' roles of hdpe 3/4'' pipe which would leave me 25' extra on each input and output to reach my heat exchanger with no welds at all

any helpfull insite i think i have it figured out it seems simple
do you think i should see a large efficiency increase based on my soil temp of 70*


thanks joe
sebring fl 33876

How cold do you want your house? Is a max of 72°-74°F enough? If you can live with that, then you don't need a heat pump, but instead you could cool with 70° water directly. This would greatly

• increase the simplicity,
• decrease the cost,
• increase the efficiency,

of the set-up.

That temperature may also be low enough to dehumidify the air.

i thought that even with the 70* ground loop temp i could only get the house to 78* or so
72* would be perfect but seems to good to be true

That depends on the performance of your heat exchanger, and how quickly you need to remove heat from the house to hold that temperature.

Yeah, either good thermal insulation of the house, or a good HX with a ground loop that can quickly take in the heat, would work. Of course, insulation is the better option.

I wonder if it would be possible to get rid of the ground loop's heat at night, say some outdoor HX?

I wish that I had some 70F ground. My basement floor is holding at just under 50F these days... :(

If you had some surface freeze protection, you wouldn't even need a water-glycol mix.

Anyways, I wonder if you have any ground water in the area?
Otherwise some of that heat you are pumping into the ground might built up after a while.

i have thought of this and now that i have heard it from someone else, i think i will do it... maybe with a automotive style radiator and fan and have it automatically controlled by temp difference and as an assist under full load

at 5' 6'' there is wet clay and i think somewhere around 6'-7' there is ground water
the guy i spoke to with the heat exchanger said that for my application wet ground is the best because the heat tries to drive the moisture away from the loop feild




my concerns really are with adapting my existing a/c unit
any thoughts
thanks for the replies

Those heat exchangers have 2 inputs and outputs for the water.
That seems like some extra plumbing is going to be required.

What is your 'existing ac system'? What will be required to adapt it to connect to the new exchanger?

yea just a little extra brazing on the water side.
my a/c system is 24,000 btu's with an outdoor and indoor air exchangers
hookup as far as i know will involve removing outdoor exchanger and brazing in the new water exchanger