Retaining Walls

DocHeb · Jun 25, 2001

Take a look at this site for a solution to water retention behind walls:

http://www.americanwick.com/vdapps.html

mlmartin · Jun 25, 2001

MarkV,

Here in central Massachusetts the temperature below the frost line is never that warm. I've given thought to using a similar scheme for air conditioning. Ideally, having a house with a long upward slope by the house. Bury multiple clay/concrete culverts the whole length of the slope. Add input vents with screens at the uphill end. Put a dry well at the downhill end and then take the air into the house and distribute as required. You would end up with a supply of cool, (and more importantly) dry air. The longer the run, the dryer the air.

As far as additional heat storage is concerned, I've gotten myself convinced that I will have pleny with 3 1/2 cubic feet of rock per square foot of greenhouse. If I do anything, it will probably be to insulate the north wall.

Matthew

StoneHeartFarm · Jun 25, 2001

Matthew,

I understand the dry well, I basically did the same thing with my cool tubes, making a gravel filled sump at the bottom. Is there a reason you would use clay/concrete culverts as opposed to large diameter PVC?

SHF

mlmartin · Jun 26, 2001

Clay or cement culvert sections will transfer heat more quickly. The inside surfaces are also rougher than PVC giving more surface area for condensation. We're talking the about getting the last few percentage points of performance. I wouldn't rip out PVC to replace it with cement/w3tcompact/icons/smile.gif

Matthew

StoneHeartFarm · Jun 26, 2001

Matthew,

Okay, that explains the dry well, since the joints in the clay pipe would tend to admit moisture during a heavy rain and a drywell would probably have the capacity to remove it. /w3tcompact/icons/smile.gif

Sounds interesting. What are you going to use for the riser? (The stand pipe that exits the ground at the end.) With an up hill slope, you will get natural gravity feed of cool air during warm weather. Unforntuately, during cold weather you would have the opposite effect as the warm indoor air flows outward. What is your plan for closing the loop in the winter?

SHF

mlmartin · Jun 26, 2001

I'd put in a drywell with PVC as well, since relative humidity around here can be 90+% fairly often in the summer. You have to have a place for the condensate to go. Of course if you have an uphill grade to your house you can dispense with the dry well, but at the added expense of using a blower to pull the air up into the house.

I'm not actually going to implement this scheme, since the grades here don't lend themselves to it. I'd use a UV stabilized ABS risers with a couple of 90 degree elbows to point the inlet towards the ground. Removable end caps should take care of closing the inlets in cold weather.

There is another variant on this scheme that uses underground heat storage and heat pumps. The idea is to bury pipes well under the frost line to carry water for the heat pump. In the summer, you use the ground temperature water to cool the condenser side of the heat pump and put the heated water back into the ground. In the winter time you do the reverse. The heat pump extracts the heat from the water and puts the chilled water back into the ground.

If you have enough area you can really save on heating and cooling costs. I'm not sure that it would be economical to do unless you were raising and existing grade by 8 feet or more for some other reason. A few thousand feet of 1 inch black poly pipe is cheap enough, but digging down that far isn't.

Matthew