Building Reserve and Using KWH

[bcroe]

most of the former Monitor dealers got out of them and jumped on the bandwagon to sell minisplits for heating as there was good incentives from various state bodies and lots of PR in the news. His plans for retirement are delayed as his phone is ringing a lot more often. Folks thought a mini split was an adequate year round heating source in Maine and a couple of long stretches of cold weather in the last few winters have convinced folks that they need a backup heater for really cold conditions as the electric heat they ended up depending on during those stretches really hit them hard in the wallet (stories of $500 monthly power bills were in the news). He has had to ramp his business back up and switch a part time employee to full time to deal with the calls, old units are being put back in service and he is going through his inventory of salvaged units to rebuild what he can and salvage parts for other customer units as the demand is high for existing installs and new installs.

Not sure where you are located but it will be interesting to see your experience with cold conditions. My tolerance is anything over 30 degrees outdoor temps I get enough heat if I set the thermostat and forget it. I can stretch it down to as low as 20 F if its a sunny day so I am getting passive solar gain. Add in any precipitation and the output drops and the unit starts to go into defrost mode frequently. I can get heat down to -10F but its not very warm and not very much. I switch over to my wood boiler with storage once the outdoor overnight temps go under 30 F so the mini split switches over to supplemental heat on sunny days to stretch my storage capacity.

About the most extreme cold here is -20 F in northern ILL. My old heat pump (deceased) could manage
to about 20F. The new units should drop that more than 30 degrees. I do not expect them to cut out there,
but rather to eventually be unable to cope with the house increased heat loss. If that happens they will still
be saving a lot of energy, resistance heat making up the difference. This will not cause me $ loss. The
original design was to replace 1100 gallons of propane with 28,000 KWH of resistance electric heat, which
has been achieved several years so far.

This winter will be the first trial of how these figures play out. I will not be surprised if the barefoot minis
miss the target. Rather I hope to figure out exactly what the target is, then think about the best way to get
there. Having already generated enough energy for the year, this is fine tuning so that managing energy
takes the minimum of my attention. I'll also be noting if some cool areas need more air directed to them,
or are candidates for another mini. The minis have programing for direction of the output air.

Note, the usual selling points for this stuff is best efficiency when operating (SEER), but my criteria will be
how well they make it through winter without adjustments. There are a lot of mini types out there, and
these specs vary greatly. Summer cooling I expect to be a slam dunk here. Bruce Roe

[peakbagger]

I ran into a family friend in Maine who was involved with the vented kerosene heater market (Monitors) from very early when the were introduced to the US. Monitor pulled out of the market quite awhile ago and the still available Toyos were not marketed well (reportedly that is changing) so he figured around retirement age he could retire and not leave any customers in the lurch. The Monitors were the popular brand and the name Monitor pretty well meant a vented kerosene heater. They haven't been heavily promoted for years and most of the former Monitor dealers got out of them and jumped on the bandwagon to sell minisplits for heating as there was good incentives from various state bodies and lots of PR in the news. His plans for retirement are delayed as his phone is ringing a lot more often. Folks thought a mini split was an adequate year round heating source in Maine and a couple of long stretches of cold weather in the last few winters have convinced folks that they need a backup heater for really cold conditions as the electric heat they ended up depending on during those stretches really hit them hard in the wallet (stories of $500 monthly power bills were in the news). He has had to ramp his business back up and switch a part time employee to full time to deal with the calls, old units are being put back in service and he is going through his inventory of salvaged units to rebuild what he can and salvage parts for other customer units as the demand is high for existing installs and new installs.

Note sure where you are located but it will be interesting to see your experience with cold conditions. My tolerance is anything over 30 degrees outdoor temps I get enough heat if I set the thermostat and forget it. I can stretch it down to as low as 20 F if its a sunny day so I am getting passive solar gain. Add in any precipitation and the output drops and the unit starts to go into defrost mode frequently. I can get heat down to -10F but its not very warm and not very much. I switch over to my wood boiler with storage once the outdoor overnight temps go under 30 F so the mini split switches over to supplemental heat on sunny days to stretch my storage capacity.

[bcroe]

Today perhaps is a benchmark day here, a lot of stuff got done or fixed or operational. Beside the Honda
420,000 mile maintenance and a few other things, the house energy plan is fully operational.

It started with cleaning up vampire electric loads and propane leaks a decade ago. 5 years ago the PV
renewable energy source started up, and has been much upgraded for more energy and less maintenance.
Electric power distribution has been upgraded for less loss and better instrumentation, getting attention to
fix my broken well as a bonus.

Now the house is heated and cooled by 3 mini split heat pumps, which require little attention and save huge
amounts of energy by operating efficiently in nearly all the weather variations here. Completed just in time
for the arriving cold. As a bonus the HVAC is decentralized, so no one failure can leave me in a desperate
winter situation. There is a long list of other advantages to this upgrade, no downside found yet.

Expectation is the next energy half year will be spent making observations of limitations of the complete
system.I have a few particulars, like are more peak BTUs per hour needed for the coldest days, or even
justified with the substantial electric resistance heat capacity still on standby? When the observations are
collected, another round of upgrades might happen, I hope they are much lessor than those past. Bruce Roe

[bcroe]

The info says the units are pre charged for up to 15 feet of line. Since mine are only about 5
feet, about all needed was to vacuum the air out to 500 microns, then release the unit charge.
Bruce Roe

[PVAndy]

Just in time for some 40 F nights, 2 of the 3 mini splits are now operational. The entire house
remained in the 70s, that should be more uniform when the 3rd mini is operational. So far they
are just as everyone says, extremely quiet. That in gross contrast to my earlier technology heat
pump rattling the house (probably poor installation). It broke down every 2 years, and was only
effective down to 20 F. That heat pump and the backup propane furnace both relied on the
house air blower, required to avoiding freezing. Now the minis have de centralized HVAC.

Later the minis should reflect on the KWH reserve generate by the PV solar this summer and
ongoing. The most severe test will be their ability to handle the coldest weather, below zero
here. Several pretty substantial resistance electric heaters remain available, hope they are
not used at all. And the long term question is, how long will the minis last. Bruce Roe

Bruce

Curious,, did you use the factory charge or did you have the lines nitrogen purged and refilled? In many cases the factory charge is not optimum.

I run 4 minisplits and a heat pump pool heater with a 20kW PV system with surplus power banked at the March buyout (which is fixed in Conn)

Andy

[bcroe]

Just in time for some 40 F nights, 2 of the 3 mini splits are now operational. The entire house
remained in the 70s, that should be more uniform when the 3rd mini is operational. So far they
are just as everyone says, extremely quiet. That in gross contrast to my earlier technology heat
pump rattling the house (probably poor installation). It broke down every 2 years, and was only
effective down to 20 F. That heat pump and the backup propane furnace both relied on the
house air blower, required to avoiding freezing. Now the minis have de centralized HVAC.

Later the minis should reflect on the KWH reserve generate by the PV solar this summer and
ongoing. The most severe test will be their ability to handle the coldest weather, below zero
here. Several pretty substantial resistance electric heaters remain available, hope they are
not used at all. And the long term question is, how long will the minis last. Bruce Roe

[azdave]

A few years ago, we installed one at work to supplement cooling in the server room. I think we paid $4500 for the install. It included boring a 8" thick tilt-slab walI, a roof penetration and running extra long lines to get the condenser on the roof of the second story. When I am on the roof, I often can't if tell the compressor is running unless I see the fan spinning. The circulation fan inside the server room is louder than the compressor outside. Hope your's is the silent type too.

[bcroe]

I am running out of other details, about time to do the scary part, hook up the freon and see
if my 3 mini-split heat pumps actually work.

They are mounted well above the snow. I am not expecting a lot of noise from the compressor.
But if the wall transmits too much, I will need to build a ground mount platform the same height.
Bruce Roe

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[bcroe]

Anybody have experience with professional cost to install a Mini-Split, including running
the AC power to a new double breaker? I see the DIY cost as running just under $2K.

Today worked on moving some stuff to make room for the remaining units, moving right
along. Bruce Roe

[bcroe]

The mini split conversion project is moving along, despite the amount of rain received in the last
month. Sure am glad the trench project was finished before that. I see it as being done in 3 phases.

First phase is get the interior unit mounted, which includes drilling a hole through my brick wall that
conducts a pair of 410A freon tubes, a 4 conductor cable, and a drain hose outside. No thermostat
or other interior wiring needed, it has a TV style remote control. Part of the challenge here is spotting
the hole so only one brick is affected. These high tech units even have that little scanner hanging
down, which checks the temp throughout the room, and operates the vent slats to direct air as needed.

A phase is running the 240VAC power out to an outside disconnect box. Earlier this year a 40 breaker
distribution box was added, with all HVAC loads and a few other heavy hitters along with PV solar
transferred over. This provides the space for 3 or more double breakers to feed the minis. This box
runs through a bi directional spinner KWH meter, making it possible to keep track of energy reserve
at any time.

Last each outdoor compressor unit goes onto the wall, with the help of some strong friends, less
than 100 lb. 7 electrical connections are trivial, the only challenge should be properly connecting,
evacuating, and charging the lines to the indoor unit. The compressor unit is already precharged
with enough R410A for a system.

There is no shortage of Utube videos on how to install mini splits. I watched quite a few, none
cover the entire job. Hope I am getting it right. Bruce Roe

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[bcroe]

Today did the install of the Mini-Split indoor unit. Not very heavy, but would be easier to get everything
lined up with 2 people. As expected it was just a matter of getting some holes in the right places. With
apparently no technical difficulties, will go ahead ordering 2 more for installation this year. MiSpIn3.JPGMiSpIn5.JPG

The design puts all the freon tube connections outside, seen sticking out (plugged) with the drain. The
compressor unit is pretty light as well, seen here with the bracket for mounting on the wall (well above
any snow). Have a jug of R410 and borrowing a premium vacuum pump for the lines, unit is precharged.

MiSpIn6.JPGMiSpIn9.JPGMiSpOt1.JPG

Compressor is relatively light, plan to hang it above the flower garden on the wall. Needs proper
drain (outside), and light 240VAC with disconnect, no problem. House wiring is ready to accept 3 of
these mini-splits. These will be checked out over winter 2018/19. If they fall short of capacity, can
put in one or two more next year. Anyway my older heat pump has quit and I don't want to waste
more resources on it. Bruce Roe

[bcroe]

And, the propane system is still in place, it with my generator could supply heat for a while in
case of an extended power outage. I use just enough for clothes drying and another building
so that my supplier doesn't disown me. Got my annual refill, noting the best summer price is
now $1.30 a gallon. Just a short time ago it was $1 a gallon, solar is looking better all the time.
Bruce Roe

[bcroe]

I take it you already moved your system anniversary date once? PoCo's in NJ let you change your anniversary date once (and only once) after the install of your system to maximize self consumption prior to true it. It might be worth a call.

Huh, me? Never changed it, the other possible date is for wind power.

My impression is, that mini-split heat pumps are just not accepted in this area. Asked one service guy,
he said he had never seen one. But last night I was surprised by a local TV ad. Their approach was
that if you have hot water heat, your house may not have any central air distribution. But you can add
zone control with a mini-split, no ducting. I also spotted one behind an exercise place last month.

They did not mention the things that are driving me that way. Double the electrical efficiency over the
old centralized units, and ability to operate down to minus 13 F (covering 97% of the time here). Will
be noting if this starts a local trend.

Meanwhile the first of 3 house locations is ready to install, the inside and external units are next to the
wall. One year ago there was a problem of enough double breaker positions to operate this equipment,
though the total drain is decreasing. This 1978 originally all electric house (my neighbor still is) had
some heavy wiring in place for the original electric heat, unused after the PO converted to propane.

I repurposed this wiring to a new box which is dedicated to the relatively few devices that are heavy
KWH users/suppliers. With a bi directional spinning disc KWH meter in the feed, my reserve summer
buildup and winter drain down are mostly displayed, the original box has lots of circuits but very light
KWH load. The disc does 34 rpm when the sun is in position.

I also picked up a better vacuum pump, gave my R22 bottle to a friend who still uses it. The backup
of some 6KW resistance heat will stay for now.

Anyway, my last, now obsolete heat pump seems to have kicked the bucket. Bruce Roe

[JSchnee21]

I take it you already moved your system anniversary date once? PoCo's in NJ let you change your anniversary date once (and only once) after the install of your system to maximize self consumption prior to true it. It might be worth a call.

[bcroe]

Thanks for the mini split info. I did get to experience them with my cousin hundreds of miles north,
I found no fault and she likes them. The very good COP and operation to 13 F below zero should
be a big improvement over what I have.

I figure a minimum of three (at 9000 btu) should be immediately installed on this strung out ranch,
2000 sq ft. Of course the basement is the same size and treated like another floor, fully heated.
After a year, will decide if there is a place another mini is needed. Bruce Roe

The first mini split is ready for installation to begin, more of my scheduling problem than technical
I do hope. Bruce Roe