Geothermal for whole house. Connect to tanks, too?

["Umm, fish?"]

Hey! I'm working on a large house remodel if I can ever get the bugs out with the city. We're planning to run a vertical geothermal system to run the heating and cooling for the entire house. Now I know that it can be set up with each room with a separate thermostat, but can I work the tanks into this deal? If so, how?

My concern is that it seems like from what I read that heating and air conditioning are two pretty separate functions in these systems. Like you have to manually flip a switch to switch between functions? But I can certainly picture times when the tank needs to be cooled and the house needs to be heated. So ... what to do?

And what if I wanted another zone, too? Maybe for, say, a colder water tank? Possible?

Anyone versed in these systems enough to lay it out for me?

Thanks!

[H20ENG]

Wow this would be fun! It could get pretty crazy though getting it all ironed out.
One way I see it is if you had an exchanger for hot water and a second cooling source (possibly the geo water itself).

Or, 2 HX coils with solenoid valves in the sump or seperate vessel. One is for cold water, tied to the geo loop supply to your heatpump. The other is for warm water, tied to the return of your geo loop. BUT you only get warm water while the heatpump is running. Your cold water will be constant (assuming your Heatpump does not heat saturate the ground around your coils). Also your loop pump would need to be sized to run through the HX loop or alternatively you could use zone pumps rather than zone valves.

You are correct that most geo systems are either in heating or cooling mode. Generally the mode of the unit will match that of the needs of your tank (htg or clg)

Probably the best would be a seperate solar heated drain back tank and geo cooling. Then use the dual exchangers. This has been my dream system for awhile.

["Umm, fish?"]

Thanks, although I have to admit that I haven't digested your whole response yet. But, a couple of quick points.

Can't do solar due to the age of my house and it's orientation. Specifically, my house is old and that means the city gets a say in how it looks and the house faces south so the solar panels would be visible from the street. Maybe I could slip in one of those new flat flexible panels that are for heating water in a water heater?

You are correct that most geo systems are either in heating or cooling mode.

More . Couldn't this be handled? Don't we have the technology yet? If temperature is <= x then set switch to heat. If temperature is >= x then set switch to cool. We're already measuring the temperature at the thermostat, afterall.

Would it be easier to just ask them to sink some extra pipe while they have the hole digger out and have it completely separate from the house system?

Okay, some of Paragraph 2 in your reply is starting to sink in as I write. So, this system could give me a constant supply of cold? Wow! I could T a line off before it got to the heat pump and just have constant running cold? Sorry to repeat myself. So, making a cold water tank sounds a whole lot easier (and cheaper) than I thought it might be.

Thanks! I'll keep thinking this through and hit you with some more questions, if you don't mind.

[H20ENG]

Andy,
No problem, its fun to think these things through

I'd def put more coils if you can afford it. Yes, the geo loop will recirc the earth temperature water, so in your case it will be easier to get cold water than warm.

Yes, a heat pump T-stat can be set to maintain a certain temp, switching from htg to clg as needed. The problem is it will cost you alot of energy to run the HP just for your tank. Your home doesnt need to be maintained at such tight temp tolerances for comfort.

The HP, in cooling mode will heat the geo loop water. Many installations use this heat to preheat the incoming domestic water that feeds the water heater. You can do the same thing and have it also loop into a storage tank, banking some heat. Depending on your system size, this may NOT be cost effective at all. Cool as hell? Yes

When the HP is in heating mode, the geo loop gets even colder, and you lose any water heating, since its all going into heating your home. In your case, you will probably have to stay with heaters. If you can get some tank heating out of your system, it will be in summer when you dont really need it, unfortunately.

HTH,
Chris