Using attic heat to warm up basement

[AC_Hacker]

Originally Posted by Xringer

...proceeds the RH spike from the dryer exhaust. I noticed the basement temps jumped with the humid air blast from the dryer.

So, you are venting the moist dryer exhaust directly into the basement?

-AC

[Xringer]

Originally Posted by jeff5may

Looks like you could stand to run some of that hot attic air straight into the airtap. It would definitely boost the cop of the unit, while offsetting some of the cooling of basement air. Literally moving the hot attic air into your water heater at high efficiency. Maybe a couple of lines in the plc code to run some warmish, more humid air towards the unit for more latent/less sensible heat removal? Hot, humid attic air turns to cold condensate down the drain rather than cold, dry basement air...

The reason I'm trying to move the hot air down the basement stairs,
is because I don't have any good place to install duct work from
the attic down to the basement. So, this setup is a compromise,
since a little heat sent to basement is better than nothing.

The humidity sensor checks the outdoor RH before turning on the blowers.
So, we never pull much damp air into the house.
Maybe a little leftover damp air in the attic, right after the outdoor humidity drops.

[Xringer]

Originally Posted by AC_Hacker

So, you are venting the moist dryer exhaust directly into the basement?

-AC

Nope, it goes out a vent on the north side of the basement.
The outdoor sensor pod is located about 5 feet east of the exhaust vent.
So, when the wind is blowing from the west, the warm moist air flows
along the back of the foundation, right to the sensors!
So, I've got to move sensor pod to a better location.

Just got done installing the new CAI board this morning,
and so far it's working okay. Just had to change a few lines of code.
The X10 commands have changed with the new version firmware.

Here's a screen shot of the new status page..

[jeff5may]

I know y'all will hate this, but this is what I did in my last (rental) house:

I ran the airflow backwards thru the (crappy) central air system from upstairs during the winter. There was one 5" supply duct for the whole (semi) finished attic, which did not supply enough heating or cooling upstairs in any conditions.

So I grabbed a squirrel-cage blower, turned it on low speed, and set it directly on the lone register upstairs. I had my window unit heat pump up there, set on auto, to regulate the upstairs as its own zone. It ended up saving me like $1000+ last winter in heating bills. Basically, the blower was heating and cooling the downstairs from above, as well as tempering the crawl space through the leaks in the ductwork.

In this new (rental) house, I substitute an under-vented, partially finished basement for a second story. The solution here: the same (hacked) window unit does its thing downstairs now, plus I opened up the return air plenum and run the central system fan on low when it needs it (playing with cycle timer settings now).

[Xringer]

My daughter's house has a messed up central heating-cooling system.
It was the second system installed in the house, and uses much of the old junk ducts..
Hardly any cooling on the second floor.. But, in the winter, the heat comes up the stair case..
She needs a couple of Mini-splits!
~~~~

PM Update:

I moved the outdoor sensor pod away from the house.
It should not be effected by the dyer's exhaust, in it's new location. (I hope)!
I also removed the 'spare' outdoor heat sensor, from the pod. DS18B20

I moved the basement heat sensor away from the A7 and dyer..
It's now near the base of the basement stairs, about 5 feet up off the slab.
Now, it won't be directly affected by the IR heat coming off the water tank or the dryer.
This should give me a much better picture of air flow from the attic. (being near the stairs).

The new CAI board seems to be working okay, a bit of late day sun came out and fired up the blowers..

Tomorrow's weather promises some good logging..

The new layout:

[Xringer]

The sun was out and the attic was warming up pretty well, but the program
was waiting until the attic hit 65F.. That took a while. Seemed like too long..

In the middle of the day, I modified the program to use a floating setpoint.
The new setpoint is updated every 15 minutes and uses the basement temp+3 deg.
So, if the basement has warmed up during the day, or gotten colder (A7 run),
the blowers won't run, unless the basement 3deg F cooler than the attic.


Now, don't have to worry about changing the setpoint..
All I need to do now is evaluate that 3deg number.
Should it be 3.5 deg, or 2.0 deg.?.

[Xringer]

Kinda shows what I've been talking about, in one dimension..
Maybe I should make a video..

[Xringer]

The attic hit 64.7F at 13:19 and that was about it..

[Xringer]

After looking at the temperature data for the basement during the last week,
and seeing pretty mediocre results, I was somewhat disappointed.
I know it's really hard to heat an uninsulated basement, with a floor slab
that's kinda cool all year round..
But, I want a bit more than a 1 or 2 deg increase in basement air temperature.

So, I'm thinking about replacing the back door (and storm door).
That glass is always cold. It's facing north, so there is no sun coming in,
and just a 1956 32"x80" wooden back door and aluminum storm.
The only good thing about it, is the glass provides a little light during the day.

Not being a door guy, I'll have to study this project a good bit, before
taking it on, or hiring someone to do it.

In the meantime, I've been taking some temperature readings. That door is cold 24/7!
I think it's effect on my warm-attic-air experiment is much larger than expected.

So, today I'll be taking data with a new factor added.
Last night, I covered the top (glass) part of the door with clear plastic.
Also went outside and covered the glass part with a second coat of plastic.
For today, the plastic isn't sealed around the edges very well, just a few push-pins.
But if today's data looks any better, I'm on the right track..

[Xringer]

Good solar day. Warm.. We went for a 15 mile bike ride and had lunch outdoors.

The basement temperature gain was 2.7deg F. Not really that good.
The hotwater gain was excellent.

I'm wondering if this job is too big for 70-80deg F attic air @ 200 CFM.?.
Thinking about doing a little testing with a space heater.
Dump in 4,000 BTUh for a few hours and see what temperature gain we get..