Geothermal heat pump

[bushmanpat]

Has anyone had any experience/know anything about ground sourced water to water heat pumps for in floor heating. Seriously considering it for a new build, but there's not much around about it. I live in a cold climate, Winter has occasional snow that sometimes settles and we often have a month where we don't see double figures on the thermometer. HAve only heard great things about it, apart from the cost.

[Timmo]

I've had a bit to do with the geothermal system at AGSO in Canberra which has a similar climate to Lithgow.

Here's a bit more info http://www.ga.gov.au/image_cache/GA10493.pdf

I've also heard of one in Tasmania which produces chilled water.

[wonderplumb]

Is there that much ground water up there though?? I would suppose it depends on which part of town your in. Thought about solar-backed electric heating? It goes on top of the waterproofing and under the sand/cement tile bed and apparently a lot more cost effective than the heated slab treatment. Just a thought.

[woodbe]

Got one, but it's for ducted, reverse cycle A/C. I don't think I've ever seen it referred for in-floor heating, how does that work?

Ours has been in for a long while now (10+ years) When it went in, the costs were divided roughly a third each for: The Loop; The Unit; The Ducting. Without the ducting you might save a bit, but you'd lose cooling capability I guess.

Do buy from a reputable installation company. Small errors can be expensive in terms of time and cost with this gear. If it is 3 phase, you absolutely must have a phase-failure device to protect your compressor. Make sure the loop is treated for bacteria on installation, as well as for low temp anti-freeze protection.

What brand unit are you considering?

woodbe.

[bushmanpat]

The Lithgow hospital also has geothermal. I've heard of two domestic applications around here, but haven't had a chance to really get the guff on it. One bloke mentioned his brother had had it and it was unreal. Big tiled rooms. You could lay your washing out at night and it would be ironed in the morning apparently.

Haven't got far enough into it for brands yet. Just at the info gathering stage.

I'd be considering a closed loop, but the block has a dam. Haven't been in yet to check depth, so not sure if it's suitable.

[Smurf]

There's a similar system that was installed to heat a large swimming pool complex in central Hobart.

The only difference is that the council used a heat exchange with the raw sewage line out in the street (it's a major pipeline I'm told) rather than just a ground loop since the sewage is warmer so it's more efficient. It's still a water to water heat pump though, just the heat source is sewage and not the ground.

I know that they did have some troubles and I'm not sure what the ultimate solution was. I think those troubles had more to do with shoddy electrical installation by the contractor who wired the whole place though - there was a significant fire there at one point (bad enough to shut the whole place down for months).

Also I'm aware of a retirement home of some sort having installed one in Tas. Theirs is working OK so I'm told.

Another one, I'm not sure if they still have it though, but the Hydro-Electric Corporation was heating their head office (about 10 storey office block plus an adjoining lower building) using a heat pump system hooked up to the Derwent River circa 1990. That is salt water there and the building is only one block back from the river. It worked fine at the time but I'm not sure if they still have it.

[rhancock]

You could ask here (http://forums.permaculture.org.au/index.php?sid=47de55cf997b25889c06e506e5d0a136), someone will have some advice.