DIY heat pump??
 

I've got this little window AC that we use in the bed room.
It cools the room nicely with it's 5,250 BTU/h using only 540 watts.

This morning, it was kinda cool here in New England. It in the 50s
outdoors and in the low 60s inside the house.
To take the chill out, I plugged in a 1500 watt space heater.

Humm, 1500 watts.. Is 1500 watt-hours really equal to 5118.2 BTU/h ??

That must be right, since the little 1500W heater does heat up the room ok..

So, what seems strange is my little window AC unit is putting out 5,250 BTU/h
and it's only using 540 watts! (960W less than the space heater).

How does the AC do that?? I think it might have to do with the fact it's
pumping outside air into a hot coil and exhausting really hot air..
It's a heat pump. Pumping hot air OUT of my house, by simply heating
up the great outdoors (adding to global warming).
http://static.howstuffworks.com/gif/ac-ups-new.gif
HowStuffWorks "Air-conditioning Basics"


So, what if I turned it around backwards in the window, blowing cold air outside..?. And Hot air inside!

Would I get 5,250 BTU/s of heating for a mere 540W (instead of 1500W)??

This is the kind of stuff that keeps me awake at night.. :confused:

The problem is heat pumps are very inefficient in cold environments. The heat expelled from the condenser was originally absorbed from the air passing over the evaporator. In a cold environment there is very little heat to be absorbed by the evaporator, therefore little heat is produced.

Your window A/C unit was designed to do one thing: cool. There are larger wall mount units that do both heating and cooling, but the efficiency numbers for the heating cycle are much lower than the cooling cycle.

GT
 

But today, it's in the 50s :D
I'm thinking today would be the perfect kind of day for a mild-heat pump system. Scavenge what heat is left of the summer! :)

My backyard borders on a little swamp, and 70 yards back is a small lake (~ 100,000 sq feet). It's surface is 2 below the bottom of my back yard. This means the water table in the lower part of the backyard is only about 2 feet down..


http://polizeros.com/wp-content/uplo...stem_horiz.jpg

So, I have a giant source of 54 to 58 degree water/coolant in the ground out back.

All I have to do is plant a really big heat exchanger about 5 feet underground. Closed-loop type sounds like the best.

This morning, I ran the cold water tap for a long time before making my
breakfast drink. It didn't feel cold, so I measured it. 62 degrees!
It was room temperature! (The hotwater system was off & cold).

Anyways, that should take care of the problem of cold weather..?.

Just have to build the right kind of heat exchanger to couple into a modded AC unit.?.

Depending on your location but many people actually put their exchangers into ponds and lakes. In fact, I believe these are typically the most effecient heat pump systems. Since, I don't live so close to a body of water I never researched this type of heat pump but if you have rights to that lake and it never completely freezes you could probably save a ton of money with a heat pump.

I did look into burying my coils when I replaced my 60 year old oil furnace with an electric heat pump this last spring and the cost went from $12,000 (with complete electrical upgrade) to something like $25,000-$30,000 guess from the estimator (he said he wasn't sure cause it's so expensive he's never actually sold one). Most of that cost is in the massive amount of copper pipe needed.

But I'm happy to say that the new heat pump not only saved us in heating fuel costs, but the old heater used so much power for the fan and ignition and ditching the two window AC units that even our electric bill dropped by about $100.00 a month. Not bad, and it's all electric so it's the most adaptable of systems on the market when it comes to future energy. (Sorry gas and oil---you're all dinosaurs).




<edit> BTW...there's a lot of math involved with DIYing such a system. You need to know how many BTU's you need to keep your house X degree's and how much insulation your house has, how much heat loss etc etc.... Not to mention you gotta plan for drainage of water condensation in the coil systems in a buried line system. It's a ton of work and money and destroyed yard if you screw it up and it doesn't work right.

I'm usually all for DIY projects, (especially since I work in construction) and I'm afraid to say a buried exchanger heat pump I'd leave to the professionals. If for no other reason that if it doesn't work right they should offer a guarantee and they have insurance to dig it up and fix it should something go wrong with it or if it or they cause damage to your property.

It's good to hear from someone with a heat pump! Glad it working out so well for you. I fear this oil burner I'm using is about to bring me into a world of woe.. Luckily, it can also burn coal, wood or junk mail.. :D

I've just spent a lot of this afternoon reading about closed loop systems.
The pond loops seem to be one of the easier installs.
But, all of the hardware is kinda costly. Plus, it takes 'trained experts' to install it all for you, that runs the bill way the heck up..

It's like solar PV stuff. You price out the kit and it's $9,500 but the the total after installation is $22,000 :(

Here's a sample ECONAR GeoSource Geothermal Heat Pumps: DualTEK of what I've been reading about. The manuals at some of these sites are very informative.


The Average year-round air temp here is 48f. And I read that's also supposed to be the average ground water temp. It's just a bit higher at the end of summer.
But, I don't think it will get down to 45 by the end of winter.

If they are using ground loops for heat up in Canada, I'm sure it will work down here..

I'm starting to think if a guy just wanted to do a closed-loop system on a small scale, like 10,000 to 20,000 BTU/h, he would likely have to DIY..

If the day comes when we can't get some heating oil delivered, it might be
nice to use some KWHs without getting a massive electric bill hit.


I have a spot in the low lands of my backyard where I could dig a 90'L x 8'W trench. I'm not sure how deep I could get before it got too muddy to work.
If I could get it down to 4 feet+, I think it would work okay.
Mud might be a good sign. If the pipes are deep in mud that's below a foot below the frost line..?.

I've looked at a couple of old ACs and I think it might not be real hard to tweak an old 18,000 BTU Kenmore into use as a heat pump.
I see them for sale around here all the time. Even a new one isn't that costly if you by it in the fall.


During the hot humid summertime, that closed loop could be connected to a easy DIY dehumidifier/cooler for my basement shop!

Well, I know a few things you should consider. Soil type will influence the depth of the trench. I wouldn't necessarily hope for mud deep down. Depending on your local climate that could mean that things will freeze deeper than your "frost line". Also wet soil round the exchange coils could mean you might have condensation and humidity problems which could turn into greater problems with mold etc. inside the house.

Most systems either drain into an underground leech field or back into the house to be pumped away. If your house is supported on a basement foundation this wouldn't be a problem, you could easily slightly slope the exchangers so they drain into the house then pump/drain it there. If your houses foundation is above surface grade too moist of surrounding soil would make it so you'd need to dehumidify the air as it enters the house. If you use a leech field and the soil is constantly damp (even before the exchangers are installed) you'd get greater condensation on the tube walls which will amount to too much humidity entering the house, perhaps even in the exchangers themselves. Which (I doubt it'd happen at 5 ft. too much thermal mass over top) could perhaps cause freezing within the pipes which would be a disaster.

Even if you still plan on doing it yourself I'd at least spend a few hundered bucks and consult someone that designs these type of systems professionally, at least to determine the size and depth of your field. After all $500-1000 dollars to know you get right would be paid off really fast if you DIY'd this project. Especially if it saves you from having to add on to the exchange coils or fix slope/grade of system later.

Now let me also say I'm by no means an expert. I spent about a month exploring my possibilities before we went with the air to air exchanger. Luckily the climate here in Portland Oregon seldom gets below freezing so such a system is possible. I'm not saying that you can't do it, but I'd hate to see someone get in over their head or not think of all the possible outcomes I know for awhile there I was considering renting the backhoe and doing it myself as well, but it was one of those things that the more I thought about it the more I realized it'd be easy to get in over ones head on this project. And I do some fairly extreme DIY projects ( half wall structural cutouts, below grade egresses access points etc.).

It very well can be easier than I think too. After all before we went the heat pump route I wasted about $4,000 on electric radiant floor heating mats that I was convinced would do more space heating than they did.

Winter is almost here
 

If this turns out to be something worth doing, I'll drill some test holes and see exactly where the water table is located and the condition of the soil above it.

I might install a remote temperature sensor down in the water table.
If it gets stays around 48deg all winter, then I can think about buying
the loop pipe.. It's a plastic that conducts heat real well.

I think you are (above) talking about an open loop system.
That type of system requires that some professional wells be drilled.
I'm more interested in a closed loop system. Here's one used in a pond.
http://www.filterclean.co.uk/images/...m_pondlake.gif

Some pics on this page, half way down: Geothermal heat pumps at home

The pipe is filled with glycol and water. It's a sealed system.
The water is pumped out of the house to the loop, where it's
warmed up to 48f and comes back in to the heat pump exchanger
where the heat is sucked out and pumped into the house.

Some of the newer systems actually use copper loops and run
the refrigerant (freon like stuff) underground and skip using the water-glycol mix.
They say it's a lot more efficient..

25,000 BTU space heater.
 

I found my Geothermal heat source!

http://i46.photobucket.com/albums/f1...asementGeo.jpg

It's been right under my nose since 1973 (well, about 12 feet under my nose). The basement floor!

We have a zone of forced hotwater heat down there, but right after
you turn off the heat, that full basement slab and 8" walls swing
the air temp right back towards ground water temp..

Since this heat is coming from solar warming the earth's outer crust , my guess is by the end of winter, we might see down to around 57 or so.

My point?
I don't need no stinking pipes buried in the back yard. I've got my basement full of 64 degree air(72 today)..
If cold air is injected into the basement, the slab warms it back up pretty quick.

Now, I'm looking at the possibility of installing a large window type AC unit
down in the basement and venting the "waste" air upstairs for space heating.

This is the AC I've been thinking of..http//210.118.57.197/Products/AirConditioner/ElectronicControl/AW25ECB7XAA.asp

It would cool the basement, (while heating upstairs), hitting us with 25,000 BTU/h (Unless we used low speed). :)
Power source: 208-230 V
Power input: 2,600/2,660 watts
Power amperage: 12.8/12.0

It takes about 7,268 Watts/h to generate 25,000 BTU/h if you use resistive heating elements (common electric space heaters) .

Since the Samsung will be a little loud, I would use it during the day and go to oil heat at night. Adding a thermostat to control it will be simple. (attaching a small warming resistor to the AC's air temp sensor).

The basement will get cold, but will come back to normal overnight.

Since the boiler will be hot 24/7 any waste heat from it will be scavenged
but the Samsung AC (aka Heatpump).

Check out this small Heat Pump (for Hotwater)
 

http://www.buildinggreen.com/cgi-bin...707/AirTap.jpg


Airgenerate.com | Adaptive Energy Solutions

And, it works pretty well at cool temps too.

http://www.airgenerate.com/images/chart1_effiency.jpg

If this works in a small room (per AirTap specs), I'll bet my AC/HeatPump will
do around 200% COP in my basement.. :)

Experiment..
 

Turned the little AC around.
http://i46.photobucket.com/albums/f1...L/outdoors.jpg

Now it's in Heat Pump mode.
http://i46.photobucket.com/albums/f1.../NCL/setup.jpg

The inside and outside temps.
http://i46.photobucket.com/albums/f1...ndOutdoors.jpg

More inside temp(hall thermostat) .
http://i46.photobucket.com/albums/f1...insidetemp.jpg

After 10 to 15 minutes, the hot air was at 90 degrees. (pulling 22 additional degrees out of the 68 degree outdoor air). :D
http://i46.photobucket.com/albums/f1.../NCL/90deg.jpg

The room went up to 75 pretty quick. (That 77 is the attic temp).
http://i46.photobucket.com/albums/f1...er/NCL/75F.jpg

The Heat Pump output was a fairly large volume of 90 degree air. It didn't feel as hot on my hand as my resistive space heater.
I guess the difference is the extra width of the air flow from the back end of the AC. I was surprised how quickly the whole room got hot.

This little AC started up slowly, but soon it appeared to be warming the room pretty well.
My guess is, it was doing about the same job as my 1500W space heater, but was doing it on 540W.

I think this test was a good indicator that an AC unit can be used for heating if you have some mild air available.

This tends to make me think my 25,000 BTU space heater idea just might work. It may not be 3 times as efficient as electric baseboard heat, but I'm pretty sure it will be at least twice as efficient.

Nice to see the experiment working for you. And glad to hear you already got the pipes in your basement.

I like the the little water unit two. The combination of those two posts do get the wheels turning a little but I'm not sure where the gyroscope will end up at this point.

Keep it up I,m looking forward to the upcoming posts.

The floor downstairs is still 64.8 and holding steady. :)

I took the AC downstairs this morning (it's 66 right now) and ran it on the floor for about 20 minutes, set to 65 degrees.
Since it was just pumping heat from the the front to the back, there wasn't any heating or cooling, just some dehumidifying.
Since the coldest air down there is right on the floor, it was a good test to make sure the compressor would come on and stay on.

My test plan is to mount the AC in the wall of the little Landry room.
I'll make a strong platform five feet off the floor, and cut the AC
hole-in-the-wall as large as needed.

The basement intake air 5 feet up will be warmer.. And the cold output air
will sink to the floor.

I'll post again when I've done some more work.

Another basement test
 

Did a little testing today and posted it here:

Off Topic Lounge: Yet another heat pump test

I am doing the same thing with a window unit. I will be disassembling and building my own control unit to allow for regeneration once the coil frezes in the winter.

I will update soon.

Where are you going to get your air source? I think my plan to use the basement air might be limited to under 10,000 BTU..
So, I've been thinking about using outdoor air (like a regular heatpump) and only using it on mild days..

The Airtap HWHP at Airgenerate.com | Adaptive Energy Solutions
http://www.airgenerate.com/images/chart1_effiency.jpg

seems to do okay down to 32 deg, but I'm pretty sure it's going to get frosted over..

The basement air would be pretty dang cold if you installed 4 or 5 AirTap units in your basement..

There's a mistake in that picture. The small cylinder next to the compressor is the accumulator, not the expansion valve. The expansion valve is in the line connecting the condenser to the evaporator.

I was looking at that before and couldn't figure out the gas routing..
Since it didn't look anything like the basic diagram..
http://static.howstuffworks.com/gif/ac-cycle.gif

What is the expansion valve anyways? Just a tight spot in the pipe?
Could a cut-off valve be used? Have it open part way?

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.

"installing the reversing valves"..

Wouldn't those valves be unnecessary for heat-only system?

I've heard that the direct exchange type ground loop systems use copper in their
ground loops. That must be the best stuff to use, if you're pumping refrigerant into the ground loop.

http://www.ornl.gov/~webworks/cppr/y...res/113424.pdf


By adding heat to the accumulator you can prevent frosting. I am purchasing several programmable temperature relays to allow control of the fan, compressor, and new accumulator heater.

Will be working on this over the weekend.

Brian

That's only going to work down to 32F.
 

Per the pdf..

1.Adding heat to the accumulator during the winter heating
season will retard frost accumulation on the outdoor coil.
The frost-less concept worked as expected.However,when
the ambient temperature drops below32F,adding a
moderate amount of heat will not prevent frost accumulation
on the outdoor coil and,thus,the heat input to the accumulator
should be stopped. Heat should be added to the
accumulator only when the ambient temperature is between
41ºF and32F, where frost is most likely to accumulate on the coil.


That seems like a lot of stuff to precisely control to allow you to get down
to 32 deg.

If I could get heat out of 40 deg air & higher I could be happy with that.
When it was really cold, I still have oil & wood or coal..

Last night it got down to 36 at one point, but there has been a lot of time
during the last 24 hours when it's been above 40..
And during some of that time, I could have used some space heat.. :D

These guys have a way to pump heat out of really cold air..
Hallowell International: Products

There's a heat pump out there that has a wire running through the outdoor coils but electrically insulated from the actual coil. The wire connects to a circuit that generates high voltage, very high frequency AC (about 800v at 915MHz). When power is applied, the frost in the gap acts as a very lossy dielectric, heating up very fast and vaporizing almost instantly. The resulting shock wave blows the rest of the frost out of the coils.

That's a great idea. Explode the ice out of the coils!

Just a guess, but I'll bet that generating Zapping power at 915 mHz is not something that the typical DIYer would even think about.

Funny, I was just thinking about the ice problem the other day.
How to apply heat real fast and efficient.?. Answer, RF!
I immediately started thinking about the fancy soldering iron on my desk at work. It uses RF power (coax cable to the tip) and it warms up almost instantly. It's the best soldering iron I've ever used.. :)

It never entered my mind to light off the whole outdoor coil with RF..

HAHA! I can just picture that thing getting turned on in the summer
and working as a giant Bug Zapper.. :thumbup:

Portable AC with Heat Pump function
 

Instead of building your own heat pump you can buy portable AC units with this feature. I have Amcor 12000BTU portable unit (ALD12000EH) that we use wintertime to heat up our bedroom. (So other part of the house isn't heated much while sleeping.) This did reduce our combined gas and electric bill significantly. The only downside is that the unit is rather noisy... but you get used to it.

I looked at the specs on that one a while back..
http://www.sylvane.com/images/produc...e-h-manual.pdf
The heat works down to 41 degrees. That's okay for Texas, but it use would be limited up here.
I would be able to use it on days like today! :D But next month, it's going to stay below 40 a lot of the time.



I can't even see how it would work in heat or AC mode with only a single hose to the outside.
Some of the other heat+cool models I've seen have two hoses. One for in and the other for out.


I can almost see how a single hose could work, blowing out cold air when it's heating and blowing out warm air when it's cooling.:confused:

But, if it's blowing air out of your house, what's the source of the air??
Once my house has vacuum inside it, it will suck in air from the outdoors.
(Vents from the kitchen & bathroom)..
If it's sucking in ice cold air, it doesn't really help me much.
If the house was really tight, it wouldn't work at all.

They make window heat pumps as well.

I've been reading about those window/wall units. They cost almost double the price of a regular AC unit. And are pretty dang efficient.
But, when the temps get down under 40 degrees, they start loosing efficiency due to defrosting requirements or, they just frost up and stop working.


If I had the voltage wired in, and warm-air duct work, and the money for a Hallowell system, that would be my choice..

Hallowell International: Acadia Heat Pump

They work pretty well at very cold temps..
http://www.gotohallowell.com/assets/...hrenheitLR.pdf

Maybe next summer I'll see about installing their hotwater HP, if it's ready to ship by then..

Concerning the single hose portable AC, those work well as long as outside temperature is not too cold or too hot. As you figured out they cause vacuum to your house and replacement air is coming from the leaks of the house. I do not use these if outside temp is below freezing, or above 100F... In those conditions the efficiency becomes miserable.

I wonder how a reverse AC unit would work if you had it facing the south, then enclosed the area along the house with a clear plastic lean-to with the ends open. It could raise the ambient temp on a sunny day and provide a bit more efficiency. Maybe?

I've been thinking about that too. Add-on green houses or 'sun rooms' are
pretty nice heat sources when south-facing.

If you installed one using some good thermo-pane windows, and had the whole air-space well insulated, you could just pump the warm air into your home using a simple fan.

But, if you went with plain glass or plastic, you would need to get the air space up around 50 to get good results with the reverse AC unit..
The larger the air space, the better!

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??

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.

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..

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.

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

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.

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 :eek: 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.

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.

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

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!