DIY heat pump??

[Xringer]

Originally Posted by duaneb9729

the expansion valve is a device that meters the flow of refriderant to allow for the maximum amount of cooling/humidity removal.

conradpdx, very little copper is involved in a in ground heat pump system, lots and lots of pex pipe is used for the transfer of heat from the ground to the heat pump.

i personaly have a carrier air to air heat pump, rated at a 16 on the seer rating scale and mated to a two stage variable speed 95% efficient furnace, this will be my first winter with a heat pump.

i have the controls set up to change over to the furnace at 30 degrees, air to air heat pumps are way better than they used to be. but still have a ways to go, i am experimenting at my own home, i am a heating and a/c contractor.

and as the technolgy improves we will move into the ground source heat pumps today it requires a very very large investment and so far would be a wonderful investment for the next home owner! but yes they do work

one of the troubles with converting a window unit to use as a heat pump, is what to do with the excess refriderant and installing the reversing valves and other electronic controls, a very expensive task and possible for an experianced heating person to do but with much effort.

How has that 30 degree setting worked out for you this month?
I'm seeing a lot of days in the 30s up here (near Boston)..
It's been down to the 20s too this week. Making me think
about a ground loop..

So, how is the Home experiment going so far??

[duaneb9729]

i am waiting for my first electric bill to come in, but so far its keeping up with our local temps.

i did learn (the hard way) that i shouldnt use a big temperature difference with my set back thermostats, primarily because it takes much more time to recover from it.

the temperature at the supply register is much lower than my gas furnace puts out. aprox 10 to 15 degrees different.

so far the gas furnace hasnt run much, just on a couple of 18 degree mornings.

if i didnt mention this before, my heat pump is a two stage unit, coupled with a two stage variable speed fan, furnace.

so when the temperature is above thirty degrees, and there is a call for heat in one of my zones, the heat pump runs on low stage and the furnace runs on its low heating speed, aprox 50% of its full heating fan speed.

from there my zone system and the furnace control board decide, when and how to bring the heat pump up to high stage heat.

on my zone system there is an out door temperature sensor that tells the zone panel what the out door temperature is and i can set the panel as high or low as i desire, i currently have it set to 30 degrees, i could set it a little bit lower if i had an electric duct heater to take some of the coolness out of the air. i will get back to that in a second.

once the outdoor air temperature is below 30 degrees, the furnace works like a normal two stage variable speed furnace.

in situations where an off peak meter is used with the heating system, having a electric duct heater to temper the air can allow the heat pump to work at a much lower temperature. if one was to couple this addition to my system, it would require more controls and extra wiring.

sorry for the long post.

[Xringer]

Your comment about the set-backs just reminded me I wanted to change mine.
My wife likes it cool at night, but I'm getting so old that I need it to be a tad warmer.
I'm all re-programed for a faster recovery time in the mornings.

~~
"the temperature at the supply register is much lower than my gas furnace puts out. aprox 10 to 15 degrees different. "

I've read there can be a large percentage of heat loss in hot air duct work.
Plus sometimes there is loss of air flow, due to resistance in the duct (tight turns etc).

I'm adding insulation on the basement pipes that feed my forced-hot-water baseboards. Not too hard.
I'll bet insulating duct work isn't as easy.

I've been looking at the prices on those mini-split ductless units
(Since we have no duct work at all) and they seem to be good performers.

SINGLE ZONE 17 SEER 24000 BTU HEAT PUMP SYSTEM
24,000 BTU for a measly 2490 watts.. That's like running two little space
heaters (that would give me 8500 BTU).
I like how these units use variable speed DC motors on the compressors.
So, it can run a lower speeds when demand is low.. Instead of going on and off.

~~
I knew my attic insulation wasn't too good. Since it's no where near the
recommended R38.. I've checked the attic temps this week during
the day and late at night and I can see the attic needs more 'R' factor..
My warm air is being wasted in the attic!
After a mostly cold cloudy day (not much solar), at 1 AM, it was 20F outdoors and 30.8F in the attic.. (65F indoors).

Picking up some rolls of fiberglass tomorrow..

[Christ]

My father, instead of insulating the attic, insulated the attic's floor with R60 worth of insulation, then topped it w/ a rubber/foil "blanket".

The sun on the roof keeps it warm enough up there in the winter to go up and mess with something for awhile, but the house doesn't lose nearly as much heat, and it's less area to heat up before the rest of the house gets heated.

Living in trailer parks, more recently, I've come across people who get things free all the time from those who don't know what they are...

One of my friends came across a "Carrier" central air unit, in working condition... it was one of the original units, that used a box with a radiator coil in it.. (kind of like the radiator in a car, water to air unit).

He was interested in finding a way to use it to heat/cool his home, without actually using it the way the manufacturer intended (park officials said no to putting concrete in the yard to mount the unit on.

We ended up putting a fan behind it, and running cold water through it. It was more than enough to cool the house, so we put a thermostat on the fan and the water valve. (Water is free in the park, it has a self-recycled water system.) Later he was interested in getting heat the same way, so we changed the position of it to replace the oil furnace he no longer wanted to use, and made the radiator blow into the duct work of the home. By adding hot water to it, (electric to heat the water from a "heat as required" water system) with a thermostat, again, to control the fan and the water flow, it was more than enough to heat the 30X72 modular.

This was one of the most interesting things I've ever done with garbage.

OP- I look forward to seeing more results on the heat pump idea... I'm contemplating an in-ground water circulation pump for my house when I build it.

[duaneb9729]

Xringer another place to pay attention to in the attic is where the plumbing pipes come through, plug the gaps around them with foam or tightly wrapped insulation.

newer set back thermostats start heating the house before the time they are set for, ie if you wanted it 70 degrees at 6 am, the thermostat would turn on two minutes earlier for each degree of set back, and with some of the top of the line set back thermostats they learn your system and every three days they adjust to the conditions.

now these are the thermostats i buy from a heating and air conditioning supply house, if you go to a home store you should read the boxes and see if those features are available.

one other note in your attic if you add insulation make sure you put in shoots so you dont block off your eave vents. good ventilation keeps the ice off your roof

[duaneb9729]

what we are finding is that sealing the duct system helps get all the heat or air conditioning to where it needs to go.

sealing duct systems is a good practice and one any one can do
use duct tape, foil tap caulking.

as always good installation practices make for comfortable homes that are cost effective to use.

[The Atomic Ass]

I live in an apartment now, but prior to that I lived in a room over top an un-heated garage. The duct work ran the full length of the garage to the register in my room, so while the rest of the house managed 68F, my room struggled to get 62F. Needless to say, it was bad enough that I forced my parents to invest in a space heater, the oil radiator type. 600 and 900 watt coils, and 1500w with both running.

I never used more than the 600w setting in that room, and with that same heater in my apartment, (710 sq. ft.), I managed to run just the space heater down to 40F. Below this it just won't do by itself. But it does make it much more comfortable in a room allowing me to run my 9kW central system at a lower temperature. (No heat pump here, all electric heat).

I think radiator space heaters are a lot better than the built-in fan type. Slower, for sure, but much higher efficiency.

[Christ]

Originally Posted by duaneb9729

what we are finding is that sealing the duct system helps get all the heat or air conditioning to where it needs to go.

sealing duct systems is a good practice and one any one can do
use duct tape, foil tap caulking.

as always good installation practices make for comfortable homes that are cost effective to use.

To seal the system, you just use some silicone, normally... although muffler repair (foil tape) and duct tape work for a season or two.

Good installation practices are hard to find, in most cases... and it always costs more to go back through and fix it.

There are alot of people having things built, trying to save every penny they can on the build, then getting dissatisfied, and putting it on the market with sub-standard practices having been used to build it, and never fixing anything.

[AC_Hacker]

Hello,

I've been doing considerable hacking on refrigeration and Ground Source Heat Pumps for the last year.

I ripped into an old de-humidifier and tore out the air-to-air heat exchangers and replaced them with some small liquid-to-liquid heat exchangers. I then re-charged the unit with Propane (it really works!) and did some tests. I got some surprisingly good test results.

I am now focusing on boring holes in the back yard. A bigger task than I would have guessed, but I'm persistant.

I have loads of photos, graphs, etc. if anyone is interested.

Cheers,

-AC

[Christ]

Welcome to the forums!

Maybe you could start a new thread to show off your projects to date? Pictures and graphs and Data in general are always welcome here!