Am I being a daft idiot?
- Thread starter StephenV
- Start date
Just thought I'd point out, with all the talk here about mini-splits, all air-air heat pumps loose efficiency with ALTITUDE as well as low temps (for heating). It is something that most folks know know or think about, since it does not effect them.
Be sure to look at the stats for whichever mini-split you are considering to see how well they will perform if you live at 5,000' or more of elevation. Probably will still work but also will be switching over to resistance heating strips far sooner than it would at lower elevations.
Be sure to look at the stats for whichever mini-split you are considering to see how well they will perform if you live at 5,000' or more of elevation. Probably will still work but also will be switching over to resistance heating strips far sooner than it would at lower elevations.
doing it different
Solar Enthusiast
Care to explain? Colder? Less dense air across the fins?
Less dense air. It effects the efficiency of the heat transfer.
doing it different
Solar Enthusiast
Turbo charger.
One thing that some window air conditioners do I spray some of the evaporating water at the condenser. But that doesn't work well for heating
Maybe, but have not heard of any units doing this. You'd have to run the fan faster on the inside unit as well, which might create noise issues.
1201
Net zero
Why is an air to water heat pump better than a $600 mini split. Please explain
UpNorthMan
New Member
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- Dec 4, 2021
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- 57
I also agree that a furnace needs to be vented. My cabin/future house is located in Northern Minnesota. -50f isn't unheard of. I am planning on installing this lp furnace in the future. It's vented, and can be operated without electricity. It has a fan kit that should drastically increase efficiency. And it has a orifice kit for higher elevation. And a narrow footprint. They make larger btu models. Just the first one that came up on the search.
Williams 25,000 BTU/hr. Monterey Top-Vent Wall Furnace Natural Gas Natural Gas 2509622A - The Home Depot
Keep your home warm during power outages with this Williams Monterey Top-Vent Wall Natural Gas Furnace. High altitude and gas conversion kits available.
www.homedepot.com
Hedges
I See Electromagnetic Fields!
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- 23,151
Less worried about inside unit, assuming fins have quite a few degrees rise. It probably has variable fan speed anyway.
I think the issue has most to do with choice of working fluid. Percentage change in outside temperature, in degrees K, isn't that much. Yet effectiveness of heat pump falls off a cliff. Not in proportion to percentage boost you want. (well, boost percentage is more. Outside temperature percentage change isn't so much.)
Outside, add a bigger fan ducted into it.
Bigger fan turning slower would be quieter and more efficient.
I think the issue has most to do with choice of working fluid. Percentage change in outside temperature, in degrees K, isn't that much. Yet effectiveness of heat pump falls off a cliff. Not in proportion to percentage boost you want. (well, boost percentage is more. Outside temperature percentage change isn't so much.)
Outside, add a bigger fan ducted into it.
Bigger fan turning slower would be quieter and more efficient.
1201
Net zero
Those are not the batteries I would be looking at if I were looking for batteries, even if the same size
Air to water (really soil) heat pumps are more effective for heating in cold climates. The water/soil generally stays at a constant temp (around 50F here) over the winter, and much better for extracting heat. The big BUT is it is very expensive to drill the well or dig down to lay the pipes, which is why most folks don't use them. Recently a neighbor spent like $60K just drilling the wells for such a system.
Another consideration, for cold climates, if you are not also running AC during the summer, you will end up cooling the soil around your well/pipes during the heating season and not reheating during AC season, which will require more soil/well area to compensate.
average temperature below frost line is around 55F year round, these geothermal heat-pumps need only to raise about 30F, even when outside air is below freezing
ghostwriter66
"Here - Hold my Beer"
Also - I would take the flooded batteries that are not working very well -- and recondition them ... its relatively pretty straight forward ... mainly drain the acid out of the existing batteries ... flush the cells very well with water -- followed by either rain water or distilled water ... then get yourself one of those 5 gallon containers of battery acid from a local auto store -- I think we pay something like $27 for 2.5 or 5 gallons for the premixed (can't remember) ...if its already premixed then pour it in the battery directly ... if its pure then you need to dilute it ... bang it with something a few times to get the bubbles out ... then put a 48V welder or equal on it to just shock the crap out of it ... we do 5 minutes on -- five off ... for about an 50 minutes ... and then slow charge it ... we have been able to restore about 1/2 the "abandoned" batteries that way and they literally work like new ...
BUT check YOUTUBE for better instructions ...
BUT check YOUTUBE for better instructions ...
1201
Net zero
Damn! 60k? Is there any roi for such a system? Ouch!
doing it different
Solar Enthusiast
I would have called it water to air heat pump.
I always figured the source of heat comes first,
Around here we tend to call it geothermal if a heat pump is removing heat from a ground or pond or well.
StephenV
New Member
I believe it’s 18in thick — thermal mass is an amazing thing and new concept for me : ) definitely gets windy at certain times of the year. We’re very close to Sand Dune NP
StephenV
New Member
Great feedback. We’re at 8k ft which has made several things more complicated. One of the reasons I was considering overspending on the new inverter. Though I’m opting for propane solution now. Really seems like the smartest option.
StephenV
New Member
Right. Can’t cheat physics. At some point no matter the equipment there will be a limit to their ability to heat.
StephenV
New Member
I’m wide open to suggestions if you have any in mind that I should look at. The midnight 100 ah 5.2Kw server rack style batteries have been suggested.
StephenV
New Member
Oh wow! That’s incredible. I had no idea you could do that.
Zwy
Emperor Of Solar
That sounds like work. I have a success rate better than 50% by just using the welder. No need to play with acid or flush the cells.
I have found there is some loss of capacity on starting batteries. Same as deep cycle that have had EQ charge done often. This is due to some loss of the lead plate. At some point, it is possible the damage to the lead plates from sulfation, then blowing the hard sulfation off the plate will create a weak spot sometimes high up on the plate, eventually that can break off. This can lead to a battery that self drains or has severely reduced capacity.
I've been running a recycled battery in my Honda Accord for 3 years but in cold weather it does not have the CCA it had new. I don't drive that car in winter due to road salt but do start it now and then in the shed. I've had other recycled batteries last a year or two before complete failure. My biggest problem is time. Each battery will kill over an hour as it gets cycled 5 times using the welder with the wait in between. I use 10 minutes cool down as the batteries will get hot.
Gadwall*Drake
Solar Enthusiast
I usually derate everything here by about 30%. Electrical output, mechanical output, value of a dollar. Saves a lot of frustration and disappointment. Just multiply a reliable value at sea level by .7 or so. I have a Xantrex 2000 watt inverter that will reliably put out 1000 watts, and it will reliably shut itself down and complain loudly if you try to get any more than that out of it. Most things do better than that, even cheap crap.
Back up in Summit County forty years ago, we used to refer to the 20% or so premium you paid for most things, over what it would cost you in Denver, as the "tunnel tax" since we were on the west side of the Eisenhower Tunnel. Part of that was the local sales tax, which was higher than just about anywhere else. The locals got to pay the tourist tax along with the Texans. Woe was us.
Back up in Summit County forty years ago, we used to refer to the 20% or so premium you paid for most things, over what it would cost you in Denver, as the "tunnel tax" since we were on the west side of the Eisenhower Tunnel. Part of that was the local sales tax, which was higher than just about anywhere else. The locals got to pay the tourist tax along with the Texans. Woe was us.
Any decent heat pump would compensate for this as it's monitoring internal telemetry. Newer ones run the fan (and compressor) using PWM so would speed up at higher altitudes to normalize the system. All DC.
- Mini-splits mean running refrigerant into the house which has lots of extra connections. (leak potential) 350psi vs 20psi for hydronic?
- Mini-splits make you install a gargantuan internal evap unit on the wall, unless in the rare case you have room to install an above-ceiling unit.
- Mini-splits in most cases are one outdoor unit and one indoor unit for each zone. This is ridiculous. Of course there are VRF units but few do their research, and VRF units have the same other drawbacks. The Frankenstein of mini-splits...
- Mini-splits can not heat DHW. Air-to-water can, with the same outdoor unit and a dedicated indoor buffer tank.
- Mini-splits can not be adapted to evac-tube solar.
- Mini-splits can't use the most advanced refrigerant (R-290) for safety reasons.
- Hydronic has been used in commercial buildings for 60 years, for a reason: it's the most efficient. Take a lesson.
- Monoblock air-to-water have all refrigerant in the outdoor unit, factory-sealed and tested.
- Monoblock air-to-water have a CoP approaching 5.
Mini-splits are a preposterous solution to me, and I'm a developer.
Shit, I'm OT. (White knuckles for getting relegated to Chit-Chat again...)
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