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91
Product Reviews / Re: Mini Split
« Last post by lighthunter on February 23, 2022, 02:17:19 am »
Hi Pete, yeah -7F (-21C) here at the moment. I shut the heat pump off this afternoon. Some ice bridging up at bottom of coils from snow as we just had a storm. I will have to make a cover to prevent that next year.

 When i was brooming snow off solar panels the sun was about half (over 5 amps on 8 amp panels) between the current and dark surface it melted and evaporated any remaining snow in an hour. I didnt look at OAT but it wasnt near melting anywhere else. So solar panels do clear themselves of snow especially if at correct winter angle.

Regarding open door to cool off house, HA! I have a buddy that does that often here even! Its a good problem to have😁.
It does warm here in summer, rarely over 100F(38C)usually hot is 90-95, my younger years we never worried about AC but now people see it as a requirement. Where i work is not air conditioned in the shop but offices are. Humidity here is quite high normally which counts for a lot.

I put together another graph comparing output of minisplits in heating mode and its real surprising how much variance there is. Cooling mode you are only working with a 20 degree differential so its not so much work but depending on where you live heating can require 70F (45C) of lift. The performance data is hard to obtain and for some reason doesnt match AHRI tests, very puzzling. But here it is. These are just 4 arbitrary units i looked at not necessarily the best or all inclusive of whats available. The top performer, 9Kbtu Fujitsu Halcyon XLT (hspf 14.2) next 12kbtuThermocore, (12) then a 9kbtu mrcool (12) and at the bottom, the pioneer (9.5) i have. The straight line is a 1350w resistive element which is supposed to represent consumption of each but only true of the pioneer maximum. Prices are $1800, $1100, 760, 750. The top 3 are all labled as "hyperheat" though the technology used is unlikely the same. I have not personally tested these so i cant speak for accuracy but most of the data came from mfr data sheets. Its also interesting the electricity used is not similar. For instance, the bottom one claims to be around 1250w full heat, i have verified. The Thermocore is using 2kw around the 0 degree mark. It goes down above and below that OAT. It kinda makes the graph misleading. So choosing one of these, price vs performance can be tricky as they are very dynamic animals but worth the trouble, like solar panels😁



92
Product Reviews / Re: Mini Split
« Last post by Pete on February 20, 2022, 03:13:25 pm »
It sure gets cold there in winter. Our house is very tiny, so we light the wood heater in winter and usually let it go out in the afternoon. Once the house gets to 21 or 22 degrees C ( 70 to 71F) we open the door for a while, to cool the house down.
Neither of us sleep well in a heated house, so we let the heater go out in the afternoon.
Your place is way colder than here.
What are the Summer temps like there?
Here we get a few days above 25C but most days are around 20C and below. This morning it is 4C outside and sunny. I think we are heading for about 15C today which is perfect for us.
Have fun
Pete
93
Product Reviews / Re: Mini Split
« Last post by lighthunter on February 20, 2022, 02:24:33 pm »
Hi Pete! The outside temp at 1 pm today was 45°F(7.2C). The mini S heat pump was caught up at noon to the 61° minimum setpoint. The unit throttled back to 1.97A at 240V. Im thinking it can reduce further as OAT (out air temp) goes up. It will be interesting to see how low minimum is before it just shuts off.


Its crazy how much ice has built up around it. Literally a frozen pond on a grade, easy to fall on the caboose if not careful. When warmer weather arrives, i will remount it at the same height as refrigerant pipe exit. I dont think you dare mount it above the height of the refrigerant pipes so oil can drain back to compressor in outdoor unit.
Next heating season i will hopefully be ready to run it and two more like it with a turbine and a few more panels. I want splitting wood to be an option not a must during retirement. This winter the wood boiler has been a continuous burn since october. At least ive not had to light a fire.😁
94
Product Reviews / Re: Mini Split
« Last post by Pete on February 12, 2022, 09:25:28 pm »
Thanks LH, it is good to know how much and how often they run. Still looking at them but so far I have a few years of firewood stored.
Enjoy the winter
Pete
95
Product Reviews / Re: Mini Split
« Last post by lighthunter on February 12, 2022, 07:47:16 pm »
Hi Pete! Its amp draw is usually 5.1-5.3A at 240v during heating (1224-1272w) during defrost its less. So the thermostat setting and heat load in the room will throttle it back from there. It never really shuts off unless you lower tstat setting. When it catches up to the setpoint (61F) is as low as it goes then the usage can drop back under 2 amps. Ive not watched it for the minimum but one nice thing is it runs much more efficiently once it reaches setpoint because the outside radiator isnt maxed out and wont frost as easily especially above frrezing ambient temps. I will get some numbers next warm spell.
96
Users Projects / Re: Going off-grid in Idaho
« Last post by dochubert on February 12, 2022, 04:20:46 pm »

Thanks LH,
We could all easily stay warm in winter if we could figure out how to tap the hot air all the politicians spout all the time.
97
Product Reviews / Re: Mini Split
« Last post by Pete on February 12, 2022, 03:00:00 pm »
Well is does get pretty cool at your place. Amazing that the heatpump was still working well down to minus20 c.
Does it run more and subsequently use more power when it is really cold?
Just wondering what sort of KWH per day it is using.
Pete
98
Product Reviews / Re: Mini Split
« Last post by lighthunter on February 12, 2022, 09:04:53 am »
Hey guys, were in the middle of another cold snap again. It has cycled many times this winter to the negative digits for a week or so then 2 to 3 days of mild temps which has allowed the minisplit heat pump feature very useful. Last night i fell asleep without turning it off and i woke at midnight and saw outdoor temp at -4F (-20C). To my surprise it was heating quite nicely, not a ton of heat like above freezing temps but obviously better than a plain electric heater.
I know the sales info said it could heat down to -13F but really didnt belive it would be effective. So i got to digging a bit more and it turns out they are indeed not all the same design. I kept seeing the term "hyperheat compressor" while i figured there was something to it, no company that i had read about went into detail and it seemed like more of a marketing gimick. Yet a few mfgs would list able to heat to -13 while others didnt mention it. 

It turns out the "hyperheat" compressor feature is not a standard compressor, it has 3 refrigerant pipes instead of two which is called. "enhanced vapour injection".

The unique compressor has two input ports, the traditional suction port and a mid-pressure port. An additional heat exchanger provides mid pressure vapor to this port while the compressor compresses both intakes to the high temp discharge port.

 The result is high pressure/temperature lift capability of a two-stage compressor without needing two compressors.

This feature perhaps isnt important for someone who doesnt need to heat in below freezing temperatures but i have no idea at what temps the control starts using this feature or maybe its continuous. This is a much more complex refrigerant circuit than the yesteryear car air conditioner where you had a pump, two radiator heat exchangers an orfice and a phase change gas of some type. I know you can buy these 12k munisplits anywhere from $523 to $2500.  I think it is doubtful you would get this type of compressor at the low end especially when they dont mention it. On the other end, i cant comment but the math dollar/btu doesnt seem worth it but then longevity/quality/ actual performance etc is something ive no information on.

Boring stuff to many im sure, i just thought it kinda interesting. Seems a shame this info isnt commonly included in sales literature but then many may not care.

I found the refrigeration piping diagram for this unit and it doesnt look like it has the hyperheat feature so i dont know how they get it to perform that well. Maybe by winding the compressor up to a really high speed r410A can get hot at 400+ psi. Whatever the case it seems to work well. Maybe thats the reason for the high price of the mitsubishi models, HA!

 Have a great day!

99
Users Projects / Re: Going off-grid in Idaho
« Last post by lighthunter on February 12, 2022, 08:11:02 am »
Yes. Youve done a lot of work to your system, good job!😊 You did it at the right time as batteries have become quite expensive with the politicians planned shipwreck of the economy. We really dont worry about being "off grid", some parts of the year we are but not winter months. It would require a few lifestyle changes during cloudy stuff. Water or any heating with resistive elements is a huge challenge in the clouds. Not so much in sun, we saw over 6kw coming in the other day with 7kw of panels so yes sun is getting powerful.  Its great to see your work pay off. A bit of humor, a few of my co-workers were talkin about heating fuels and one guy who has all electric resistance heating in his home says, "you should burn coal like i do". 😂
100
Users Projects / Re: Going off-grid in Idaho
« Last post by dochubert on February 10, 2022, 07:00:04 pm »

Almost the middle of Feb now and we're finally starting to get some partial sun.  I've been able to run the house during daytime hours all week (so far!).  The really gloomy days of winter makes me gloomy too.  Hoping they are mostly past for this year.  The days are already getting noticably longer.

I have been able to keep the water heating going on solar power exclusively all winter.  Couldn't do that last year so it has to be the larger battery bank plus the additional winter-only solar panels making the difference.  So I must have done something right.
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