How about Simple and CHEAP storage

[pybyr]

I've wanted to do cheapskate geothermal A/C for years, as my household water supply comes from a gravity fed spring that yields 1.5+ gallons per minute of 50 degree water 24/7/365- don't even need a pump to pull or push it. I even thought of trying to integrate such a system with the water to air HX that I put into my existing system as part of my Econoburn installation- the thing that nixed it is the fact that since the HX is over the existing furnace (whose blower I use for the water-air HX) I don't want condensation from warm, moist air dripping into the furnace.

And I have yet to bumble upon a sufficiently cheap separate air HX for the cheapskate springwater A/C, which, in my event, isn't too urgent, as it rarely gets hot enough here that I can't cool the house off with the "fan at night, windows closed during the day" regime.

 

[pybyr]

Hey,

Another option is to use a cathodic protection system. They use these on buried steel tanks that have been in service for 40-60 years. A steel tank with the correct cathodic protection would easily last my life time. But there is a cost trade off to buy and run these active systems. Passive anodes are used in hot water heaters (and the Garn boiler). No perfect answer.........

Here's an idea for you---- what's considered the "norm" for cathodic protection with most residential tanks (such as water heaters) (and probably the normal underground petroleum tanks) is passive cathodic protection-- the sacrificial anode is made of some material that is more reactive, and at the right place on the galvanic scale, to "do its thing" to protect the material that the tank is made of (such as a zinc sacrificial anode in a steel tank).

But, what's sometimes done in other applications is "active" cathodic protection, in which a slight electric current (slight in proportion to the surface area of the metals involved) is applied to protect a tank or pipeline or other structure. I am aware of at least one instance in which a huge and very old and very long (hundreds of miles) steel petroleum pipeline is protected from corrosion by the fact that one of three separate pipes is empty and is deliberately fed with current so that it gives up ions, so that the two other lines, which are in use, do not corrode.

Envision the same concept with an aluminum tank- and you could perhaps feed it sacrificial aluminum cans, charged with current, to keep the tank walls from corroding.

The above is food for thought, not a residential-scale-tested concept-- though it probably would not be rocket science for someone willing to roll up the appropriate mental and technical sleeves...

 

[Vinced]

I think Geothermal is alittle different then what I was thinking of. I found the website that I was talking about.
http://mb-soft.com/solar/saving.html

Vince

 

[Vande]

vince, As a general contractor, we looked at installing a similiar setup using the Rehau awadukt system. After we set up the foundation and utility room to accomodate the potential pipe coming in, it turns out we could not purchase the supplies from Rehau. The story we got was that Rehau atty's (US) could not be satisfied with the potential bacteria possibility . Although they appear to install these systems elswhere. So if you self install I would advise making sure you are satisfied with the ability to 'clean' the system. You might want to check the site http://www.rehau.co.uk/building.sol...heat...geothermal.energy/awadukt.thermo.shtml We never did do any similiar install in this house, as the owner was nervous after Rehau backed out. Good luck, it seems like that concept has good potential.

 

[Gooserider]

I was thinking a bit about the geothermal cooling idea last night and I had an interesting thought that I've never seen mentioned - wonder if it would work, or if there is some reason why it would not...

Seems like the biggest objection to the buried pipe concept, either liquid or air is the expense and hassle of digging the trenches to bury the pipes. However, if building, especially if making a basement, you are already making a big hole where the house will be setting...

What I'm wondering is if there would be some reason why one couldn't dig the foundation hole down an extra foot or so (or possibly just run a bunch of 12-18" deep trenches around in the bottom), lay down a grid of PEX or other piping, and back fill with compacted soil - then proceed as one normally would, with sand / gravel drainage plane, insulation, and poured slab with embedded PEX heating tubes...

Presumably one could then simply ignore the "cold loop" in the winter, but in hot weather switch the circulation on the heating coils from going through the boiler to going through the cold loop in the ground under the house?

Seems like if the slab were properly insulated, the ground under the house should be at the same 50* temp we are told it is a few feet down everywhere else....

Obviously one would have to be careful about compacting the soil to avoid settling issues, and it certainly wouldn't work for most retrofits, but any reason it wouldn't be a neat trick to use for new construction?

Thinking hypothetically....

Gooserider

 

[Vande]

I think I understand the under underslab installation, but you should send the cold water to a air handler, not to the radiant in the floors or emmitters you have. Sending the cool water through the heat loops would cause unwanted condensation on the cool surfaces. That is if I understand your previous post Goose.

 

[pybyr]

Regarding Goose's concept, I recall reading (somewhere that I cannot find now) that radiant floors can be used for cooling, as well; at the moment, all I can find is:

http://www.radiantpanelassociation.org/i4a/pages/index.cfm?pageid=97#anchor792947
which says-
"Cooling and Air Conditioning

Some radiant panel systems are capable of cooling by circulating cool water through the panel. All the principles of radiant transfer still apply. By providing a cool surface, all other surfaces, including our bodies, will give up heat to the panel. Just as in heating, this is extremely pleasant. Radiant panel cooling is most often done with ceiling panels although it can be accomplished using walls or floors. Floors become enjoyably cool, not cold. It is only when humidity is a factor that steps must be taken to avoid condensation on the panel. In this case, an auxiliary air-conditioning system is used to dry the air.

Most often a separate air-conditioning system is installed. This could be a simplified central system or a split system with strategically placed units. The advantage is zoned cooling. Using zoned cooling and placing air registers in the ceiling (where they should be), will result in summer energy savings. (return to Menu)"

Seems as though, if you could use the ground-cooled water to eliminate some thermal load, you'd have energy savings over the long haul even if you still had to do some dehumidification.

Or perhaps, run the ground-cooled water through a water-air HX first to initially cool the air and remove some humidity, and then run the less-cool water (after it's gone through the water-air HX) through the radiant panels, where it, if still cooler than the air, will still cool the conditioned space some, but with less overall risk of condensation.

[disclaimer; I am no pro- just offering food for thought]

 

[Gooserider]

I think I understand the under underslab installation, but you should send the cold water to a air handler, not to the radiant in the floors or emmitters you have. Sending the cool water through the heat loops would cause unwanted condensation on the cool surfaces. That is if I understand your previous post Goose.

Depends on just how cool the water is, and the nature of the heat loop surfaces... Most radiant loops are enclosed in relatively vapor impermeable surroundings, so you aren't going to get any real condensation on the tubing itself. As long as the tube temp isn't so low as to cool the panel surface below the dew point of the air in the building you won't get condensation on the surfaces, but will STILL absorb a lot of heat from the environment... How much, and whether or not it would be enough by itself are going to depend on the nature of the setup, local climate, etc. but even worst case it should take some of the load off of a conventional system...

It certainly would be possible to send the cooled water to an air handler instead of, or as well as, the heating loops, but I wasn't assuming that you would HAVE an air handler, or necessarily need one... A system might not have a central air distro system for any number of reasons, and I don't see that you would get a lot of benefit from installing one.

Some of the radiant cooling advocates essentially claim that having cooler floors / walls / ceilings will help produce a greater comfort level at a higher actual room temperature, so the benefit from cooling the panels would be greater than trying to use the chilled liquid to directly cool the ambient air. I don't know either way, I am mostly just speculating based on the stuff that I've read. My own situation would be mostly a retrofit, so I don't see a lot of way to do much of this myself...

Gooserider

 

[Vande]

I think it would be great if this could work. I was just thinking that the temperature of the tubing would have to be low enough to feel any benefit, that you would potentially be below the dew point. But I do not know enough to be sure one way or the other. As nice as it is in the winter to walk onto a warm floor or next to a radiator, it would be just as nice to feel the cooling effect in the summer from the same emmitters.

 

[Gooserider]

I think it would be great if this could work. I was just thinking that the temperature of the tubing would have to be low enough to feel any benefit, that you would potentially be below the dew point. But I do not know enough to be sure one way or the other. As nice as it is in the winter to walk onto a warm floor or next to a radiator, it would be just as nice to feel the cooling effect in the summer from the same emmitters.

It is supposedly fairly common in Europe, and works well over there - my assumption is that the theory is sound in terms of the cooling. I guess the two questions that seem most relevant to the idea I was mentioning are

1. Is the ground temperature under an insulated slab or basement going to be comparable to the ground temperatures in places that don't have houses sitting on them?

2. Is there any structural reason that one can't bury tubing under a foundation? I know that one normally wants "undisturbed soil" but my understanding is that code also allows compacting disturbed soil back down to a level comparable to undisturbed. Seems to me that if you pressurize the PEX, and don't bury rocks next to it that would cause punctures during compaction, that it should work - but I'm not a soils engineer...

Gooserider

 

[Vande]

My guess to #1: the ground temp will be able to recover as long as the slab next to the heated space is sufficiently insulated from the balance of the backfill/heat sink. I would guess there should be no difference between below frost level ground with a house on it or not.
#2: There are many ways to handle this situation. One might be to pour 10' walls in place of the 8' walls and backfill the interior with 2' of compacted fill after the tubing is in place at the 10' level. Regardless, I am not a soils engineer either, I had a double major, beer and females, (with honors) far from soils.

 

[Der Fuirmeister]

I've wanted to do cheapskate geothermal A/C for years, as my household water supply comes from a gravity fed spring that yields 1.5+ gallons per minute of 50 degree water 24/7/365- don't even need a pump to pull or push it. I even thought of trying to integrate such a system with the water to air HX that I put into my existing system as part of my Econoburn installation- the thing that nixed it is the fact that since the HX is over the existing furnace (whose blower I use for the water-air HX) I don't want condensation from warm, moist air dripping into the furnace.

And I have yet to bumble upon a sufficiently cheap separate air HX for the cheapskate springwater A/C, which, in my event, isn't too urgent, as it rarely gets hot enough here that I can't cool the house off with the "fan at night, windows closed during the day" regime.

You might consider an old car or truck radiator. I have an uncle (very frugal type) who used an old car radiator with a 20" window fan ducted to it. Worked well for his heat. Otherwise the cool water HX can go on the return air side of the furnace (down low) since pulling cool air through your furnace from the return air won't cause the damage to the electronics etc. that a hot air HX would in that same location.

You'll have the added benefit of pulling humidity from the air.