Geothermal & Well for Irrigation

[RoseRx]

Feed back and participation is not near as robust on the enviromental forum vs this one, so I am going to restate my question in the hopes that someone is well versed in geothermal systems.

Geothermal & Well for Irrigation

--------------------------------------------------------------------------------

What type of geothermal system would lend itself to providing for a well for lawn irrigation? My thoughts, why not kill two birds with one stone.

[aruddick]

Any open loop geo can be set up for irrigation as long as it is set up for the GPM requirement of the unit. We have done this several times. It can be as simple as hose bibs on the house with garden hoses or feed the irrigation system. are there any specifics that you had in mind?

[hvacvegas]

Feed back and participation is not near as robust on the enviromental forum vs this one, so I am going to restate my question in the hopes that someone is well versed in geothermal systems.

Geothermal & Well for Irrigation

--------------------------------------------------------------------------------

What type of geothermal system would lend itself to providing for a well for lawn irrigation? My thoughts, why not kill two birds with one stone.

An open loop on a aquifer.

A pond loop/ lake loop.

Could probably have your geo guys setup a system with a tank and valve.

If pressure in tank is less than 40 PSI, open valve. All automatic.

[RoseRx]

Guys,

Thanks for both of your replies which is 2 more than I rec'd on the environmental/geothermal site.

I am just at the info gathering stage and w/ all the incentives right now between the 30% Federal Energy tax credit and the utility co is rebating geothermal @ $500/ton, it is looking more attractive and if I can get a well out of it too, that is a bonus. Would a vertial closed loop allow for a well or only an open loop system? I know the open loop system has to be sentiment free for geothermal to function.

Many of the geothermal units also produce hot water that can be used for the home, but I have a Rinnai tankless hot water system, so how would geothermal work in conjunction with it?

[hvacvegas]

Guys,

Thanks for both of your replies which is 2 more than I rec'd on the environmental/geothermal site.

I am just at the info gathering stage and w/ all the incentives right now between the 30% Federal Energy tax credit and the utility co is rebating geothermal @ $500/ton, it is looking more attractive and if I can get a well out of it too, that is a bonus. Would a vertial closed loop allow for a well or only an open loop system? I know the open loop system has to be sentiment free for geothermal to function.

Many of the geothermal units also produce hot water that can be used for the home, but I have a Rinnai tankless hot water system, so how would geothermal work in conjunction with it?

DO NOT TIE A HOT WATER GENERATOR INTO A TANKLESS. EVER, EVER, EVER.

Your geo will produce lets say 120. Unfortunetly, a tankless has a inlet water sensor, which maxes out at give or take 100. Meaning the geo will produce hot water, the tankless will try and make a run, pickup some of the hot water from the geo, and trip on high inlet.
Went to the climatemaster geofarm in indiana last week. It was stressed not to hook up to a tankless.

You can technically do this, but: You need a storage tank. Have the tank hooked up to certain things. Maybe just the hot water for the sinks. But these sinks cannot be hooked up to the tankless, they need to be seperate.

You wouldn't want to drink from a closed loop system, or have it used for your grass/landscape.

Anti-freeze is used in a closed loop system. You get to pick glycol (poison), ethanol, or methyline (flammable).

Meaning if you were to attempt this, you'd pick ethanol, since it's best out of 3. Then the problem becomes maintaining the right mix. So, lets say you dump some of your closed loop out, and jerry rig an auto-refill. Now you don't have the correct mix of anti-freeze.

A closed loop is meant to be closed. No water should be removed, no water should be added.

An open loop is just as it sounds. You can add water, you can remove water. The geo doesn't care, as long as it maintains it's GPM.

[RoseRx]

HVACVegas,

Thanks for the info, which I was very helpful.

What do I do with the hot water generated from a geothermal? Can I small hot water tank be installed to capture it to provide for the home and when the geothermal is not generating hot water, the gas tankless hot water heater unit kicks in or are the 2 systems not compatible at all?

[meoberry]

Open loop is the only way to get what you want. Just be sure not expect one or two sprinkler heads to move enough water you need GPM to match unit requirements also need bypass to move water some where else when grass does not need anymore water. Usually rule of thumb is one gallon per ton per minute. Some manufacturers use less some more. If you have not realized yet you are going to be using quite a bit of water.

[RoseRx]

I was hoping to put in a submersible type well pump, but apparently from what you are saying, it would have to be a separate well if I wanted to use water when I needed it vs when the geothermal discharged it.

I am gathering that a separate well would have to be drilled and the only savings is that the well driller would be able to to drill both wells while there.

[motoguy128]

You could get a below ground storage tank to collect the geo discharge and install a pump to use it for irrigation. Just discharge any overflow the same as you are now. You can probably get a plastic 2000 gallon tank installed cheaper than drilling another well. That's 8 hours of irrigation at 4 GPM. You could also divert your downspouts into it as well.... but then you have more concerns about debris and micro issues. Basically it becomes a cistern.

You just need to determine how much water the Geo uses and what you demands are for irrigation and the frequency of irrigation to determine the tank size. For example, if the geo uses 1GPM for 12 hours a daty, that's 720 gallons. So if you irrigate every 3 days, 2000 gallons would be about right.

I have no idea what the water consumption is however.

[meoberry]

I was hoping to put in a submersible type well pump, but apparently from what you are saying, it would have to be a separate well if I wanted to use water when I needed it vs when the geothermal discharged it.

I am gathering that a separate well would have to be drilled and the only savings is that the well driller would be able to to drill both wells while there.

Not necessarily. Go ahead with the submersible and pressure tank. You would just need an area to dump water from bypass ie: a ditch or a low lying place that will drain off. Just remember. Watch how much your current unit runs now. Geothermal will run just as much. You will have to figure out if you can use that much water or that it will soak back into the ground, before you create a small pond in your yard. They do make a sprinkler system that works as a zone system that will water different parts of the yard every time unit comes on. Check with a local irrigation contractor for different options.

[hvacvegas]

HVACVegas,

Thanks for the info, which I was very helpful.

What do I do with the hot water generated from a geothermal? Can I small hot water tank be installed to capture it to provide for the home and when the geothermal is not generating hot water, the gas tankless hot water heater unit kicks in or are the 2 systems not compatible at all?

Thinking about it, you could actually setup your storage tank with the tankless.

BUT, you would need to have ball valves at the storage tank, and ball valves at your tankless. Wanna use Geo heat, turn the tank on, tankless off. For the tankless, vice versa.

The key is making sure you remember to close the valves.

[timebuilder]

Note:

In oder to post advice in the AOP forums, you must be a Pro member with an asterisk (*).

We have been giving leeway on this issue during the forum rollout, but it's time to get everyone on the same page. Check the AOP rules below.