precooler
 

Has anyone used a pre cooler for a heat pump or air conditioner at your house?

Welcome to ER, Larry:)

Do you mean something like an earth-air heat exchanger?

I'm planning one of those when ecorenovating our ventilation, but so far I don't know anyone who has done it. I am looking around for a DIY website, though.

Yesssssss
 

A guy in Mont?? or Neb??? Can't remember/find the site. He uses it as a heat source--with a very good design/documentation. Uses it for a greenhouse/orchard and I think his home too. This is in use in many parts of the world, I think maybe MANDITORY in Germany for passive design.

I would like to do this myself. I want to use a ductless minisplit/inverter system, but I am in a frozen hellhole with 7-8k HDD. I need 18-24kbtu at -20f

I am willing to hack to get a direct contact to earth source, but would prefer the air/air to keep it simple/in warranty etc.

A couple thou feet of sewer pipe and an airtight room/blower.

I really need to do something, I've been researching to long, and I'm all ears.

The frost line in Central Alabama is 18 in. If you trenched 48 in. and laid gravel then sewer line[for moisture control] and then blew the air across the heatpump coils , would this help the air to air exchange? How many feet of line would you need for a 2.5 ton unit? In central Al. we I need help with cooling more than heating. Where would I go to research this? Thanks for any and all comments?

Birmingham, Alabama & Woburn MA
http://pics2.city-data.com/w1q/lhaq41.png http://pics2.city-data.com/w1q/lhaq11355.png

As you can see, the average lows in Birmingham isn't even below freezing!
It's tropical compared to Woburn (my home). :)

IMHO, if you wanted a good performing ASHP, a mini-split (inverter type) should do the job easily.
If you can DIY most of the install, the unit will pay for itself pretty quick.
We normally burn oil for heat, and it cost 3 to 4 times what it costs to run the Sanyo.


My Sanyo 2 ton works really well down to about 8 or 10 degrees, (which is very rare)
http://ecorenovator.org/forum/projec...l-project.html
so it would be perfect for the Birmingham area..

IMHO, the inverter technology advances in ASHPs (like the Sanyo 24KHS72)
makes digging up the backyard look much less attractive when you live
in a nice warm area like central Alabama!

As for cooling, this thing is Great! Low noise and lots of cold air for less kWhs.
The other day when it was real humid and in the 90s, my wife came in and
told me (again) how much she loves that 'quiet' Sanyo.. :)