Building Reserve and Using KWH

[DanS26]

I called Fronius awhile back about their SunPower badged inverters. Talked to a knowledgeable tech.....he said that the upper units are exactly the same as all similar rated inverters. The bottoms are usually wired for negative ground and are normally converted to positive ground at the field location for SunPower panel installations. The only real difference is the operator/installation manual put in the box to guide installers on how to wire for positive ground. Some factory orders will specify positive ground be made before leaving the factory but that specification only affects the bottom unit.

I found negative ground in the box so I have confidence that the unit will work when needed and without modification but I will probably only need the top unit anyhow..........if the capacitors are still good......

[Mike90250]

Capacitor shelf life
As long as they are well manufactured and stay hermetically sealed, they should have a 30+ year shelf life. But if supplied by the lowest bidder.......
Operating life is dependent on Voltage % of max voltage and temperature, well designed gear should run at least 10 years, maybe more. My XW just hit 10 years, and I have a spare in box ready to go.

Capacitor forming. used to be needed with old aluminum paste caps, started off at a low voltage, and slowly ramped up over a period of hours to re-form the oxide layer that insulates the foils. Modern ones don't need it for a couple years. Might not be a bad idea to fire up the inverter, applying the DC voltage over a period of a couple minutes, and let it idle for half an hour before you pack it away for several more years.

[bcroe]

Bruce you said you keep a couple of Fronius 7.5 inverters as backups. I found a Sunpower badged Fronius 7.5 inverter on E-bay recently and went for it cheap. It came new in box both top and bottom unit absolutely spotless. Since Sunpower panels are/used to be positive ground I was a little concerned about the internal wiring in the Fronius inverter. But lo and behold it was still wired for negative ground.

But I do have a concern about the shelf life of the capacitors in this unit. My understanding that these electrolyte capacitors have an 8 to 10 year shelf life is left unused. Does this concern you?

I had not considered the issue of positive ground operation. That might affect the wiring of the
1 GFI fuse on the Fronius, I have no idea how the inverter makes that change. Guess my array
would not care if it was turned upside down.

The backups are labeled SUN POWER, and I can see some differences. They have a
disconnect switch coming out the bottom, not on my originals at that position. Perhaps I
should investigate more, even try running them one day. At least, I should not need to do
any high line voltage setup, the PoCo has tamed it and local increase is quite small.

I believe the inverters I bought were newer than mine, still sealed in the box. In operation a
switcher is really tough on the caps in the power conversion switching section, big currents
flowing in and out at the conversion frequency. Have seen that in many constructs here. That
is why some caps are rated for very low ESR. My Fronius are into their 8th year, running flat
out clipping all day long whenever the sun shines, they each draw the line at 100W more than
their rating. And at least keeping busy under clouds. So they have survived very well, but I
presume they may have aged a lot more than the ones sitting quietly on the shelf.

When they do fail, I will no longer hesitate to pull them apart and see if DIY repairs are possible.
My hope is to replace all hard stressed caps, being prepared to do the same later for the ones
on line. Could be the failure will damage beyond repair. Meanwhile, I have one backup inverter
mounted close by, all I need to do is move over the power wiring (conduit already connected) to
put it in service.

Meanwhile we are FINALLY seeing a run of pretty much sunny days, a dozen more this month
might set a record KWH reserve heading into winter. A bit over 100 KWH today under just a
bit of clouding. Reserve is helped a bit by my more efficient AC power wiring, only 1% loss
around a 600 foot loop. My DC losses are more than that at peak, but it does not matter since
the inverters are clipping anyway. At reduced (cloudy) levels, the percentage wiring loss declines
for both. Bruce Roe

[DanS26]

Bruce you said you keep a couple of Fronius 7.5 inverters as backups. I found a Sunpower badged Fronius 7.5 inverter on E-bay recently and went for it cheap. It came new in box both top and bottom unit absolutely spotless. Since Sunpower panels are/used to be positive ground I was a little concerned about the internal wiring in the Fronius inverter. But lo and behold it was still wired for negative ground. So into my parts supply area it went. Sometimes you just get lucky. I'll rip that Sunpower badge off if and when I have to hang it on the wall.

But I do have a concern about the shelf life of the capacitors in this unit. My understanding that these electrolyte capacitors have an 8 to 10 year shelf life is left unused. Does this concern you?

[DanS26]

The usual digital model is just a cost cutting and making it vulnerable to hacking. I
ought to try and find one of the older units, what is your model no? I already got a
set of replacement inverters for when mine blow up, do not want the later model.

I cannot believe all the software and monitoring swirling about so many small systems,
but I hardly ever hear of someone trying to make theirs work better. Bruce Roe

When one of the relays failed a couple years ago I opened the box to see how it worked. I thought it was well engineered and built with quality parts. There is a lot going on in that small package.

I did notice one interesting electrical aspect about the product that intrigued me. Some of the circuits were controlled by switching the neutral as opposed to switching the power. I even talked to an engineer in the company to verify that they really designed a product with a switched neutral. I think the new product design will fix that questionable feature.

Good luck finding one of these older Geyser units.....they don't break down very often.

[J.P.M.]

The usual digital model is just a cost cutting and making it vulnerable to hacking. I
ought to try and find one of the older units, what is your model no? I already got a
set of replacement inverters for when mine blow up, do not want the later model.

I cannot believe all the software and monitoring swirling about so many small systems,
but I hardly ever hear of someone trying to make theirs work better. Bruce Roe

Apps are easier to create than good engineering. A consequence of the great dumbing of America.

[bcroe]

"Thank you for contacting Nyle Water Heating Systems about the Nyle Geyser heat pump water heater. We are excited to tell you that the Geyser is currently out of production for a short period of time while we upgrade the controls to a new, digital platform. Water heaters with the new controls platform will become available in early 2021.............."
So it looks like they are getting close to releasing the new product design.

The usual digital model is just a cost cutting and making it vulnerable to hacking. I
ought to try and find one of the older units, what is your model no? I already got a
set of replacement inverters for when mine blow up, do not want the later model.

I cannot believe all the software and monitoring swirling about so many small systems,
but I hardly ever hear of someone trying to make theirs work better. Bruce Roe

[DanS26]

Perhaps I might run a Nyle 8 months a year, but with net metering a Nyle
could be on continuously. No time of day difference, just save energy. Too late for
this net metering year, should plan for spring.

Does the Nyle do anything about a moisture drain like a dehumidifier? Maybe turn off my
dehumidifier when it is operational? Now there is an energy opportunity. Bruce Roe

Yes it does dehumidify the air in my basement and I have it plumbed to the basement drain system. It keeps my basement very dry in the spring and summer. Some people collect the water and use it for mineral-less water purposes such as batteries or steam irons......it is basically distilled water.

If you run it in cold weather the heat it takes out of the air and puts into hot water has to come from somewhere....and that will be your furnace or other heat pumps. If you vent it inside and outside in the winter I think you would lose a lot of efficiency. I also do not want to dehumidify my interior air in the winter time. So a few good reasons not to run it in the winter.

I received this message from Nyle.......

"Thank you for contacting Nyle Water Heating Systems about the Nyle Geyser heat pump water heater. We are excited to tell you that the Geyser is currently out of production for a short period of time while we upgrade the controls to a new, digital platform. Water heaters with the new controls platform will become available in early 2021.............."

So it looks like they are getting close to releasing the new product design.

[bcroe]

My timer is a dual throw system which controls both the WH and the Nyle and thus will keep them from running at the same time. So here is the schedule....

Warm weather schedule:
6am to 8am WH
8am to 4pm Nyle (ie solar powered)
4pm to 10pm WH

Cold weather schedule:
6am to 10pm WH

The beauty of a gas power vent WH is that when the power is cut the heater shuts down thus I can control the WH with a simple 120v low amp timer. An electric WH would require a much more robust 240v high amp timer switch or some type of relay system.

Perhaps I might run a Nyle 8 months a year, but with net metering a Nyle
could be on continuously. No time of day difference, just save energy. Too late for
this net metering year, should plan for spring.

Does the Nyle do anything about a moisture drain like a dehumidifier? Maybe turn off my
dehumidifier when it is operational? Now there is an energy opportunity. Bruce Roe

[DanS26]

That Ohm monitor looks a bit more complex than I need. I did add temp readouts with the circulator
in 2005, switch selects points monitored. Based on the LM135 linear temp sensor.

The Nyle appears to be connected to a propane water heater at the pressure valve and the drain, the
regular plumbing left alone? Guess it would work on an electric heater as well, how it it determined if
the heater or the Nyle should run? Perhaps I should try that approach first, then switch to an electric
water heater. Bruce Roe

The Nyle works well with either gas or electric WH. The plumbing connections are all with the drain assembly at the bottom of the heater. The temp sensors are also on the bottom for the Nyle. The Ohm monitor has top of tank sensor at the pressure relief valve and a couple for the input and output on the Nyle unit.

As usual I modified the systems to my preferences. The propane heater is a power vent model which makes a little noise when operating. No problem during the day but at night I can hear it run. So I just put it on a timer system to only operate during waking hours. If some family member wants to take a long hot shower in the middle of the night.....that's their problem if they run out of hot water. They have been forewarned of how I value my sleep.

My timer is a dual throw system which controls both the WH and the Nyle and thus will keep them from running at the same time. So here is the schedule....

Warm weather schedule:
6am to 8am WH
8am to 4pm Nyle (ie solar powered)
4pm to 10pm WH

Cold weather schedule:
6am to 10pm WH

The beauty of a gas power vent WH is that when the power is cut the heater shuts down thus I can control the WH with a simple 120v low amp timer. An electric WH would require a much more robust 240v high amp timer switch or some type of relay system.

I've also added some safety to these dual systems since I am relying on timers to control things. The TMP valve is good but I don't want to rely entirely on it so I installed another high temp switch which will shut down the system if it senses a too high temp at the tank top. Probably not needed but I don't skimp when it comes to safety.

[bcroe]

Yes, that is why I only run it during warm weather. Nyle has discontinued this model will replace with the C-8 series. Not sure when.

I self installed the unit April, 2012. About 2 years ago a relay failed but that was the only maintenance I have performed on the unit in eight years. Very pleased with its output and operation. I monitor the operation of the unit with the Sunnovations Ohm Monitoring system....

http://ohm.sunnovations.com/

The Ohm system is really to monitor solar water heating but I hacked it monitor the Nyle. I get great information about my Nyle performance....top of tank temps, input and output temps, graphs of enthalpy, etc.

That Ohm monitor looks a bit more complex than I need. I did add temp readouts with the circulator
in 2005, switch selects points monitored. Based on the LM135 linear temp sensor.

The Nyle appears to be connected to a propane water heater at the pressure valve and the drain, the
regular plumbing left alone? Guess it would work on an electric heater as well, how it it determined if
the heater or the Nyle should run? Perhaps I should try that approach first, then switch to an electric
water heater. Bruce Roe

HotWatCirc.png

[DanS26]

I see a claim of COP up to 5, impressive. Is the room supplying source air? Bruce Roe

Yes, that is why I only run it during warm weather. Nyle has discontinued this model will replace with the C-8 series. Not sure when.

I self installed the unit April, 2012. About 2 years ago a relay failed but that was the only maintenance I have performed on the unit in eight years. Very pleased with its output and operation. I monitor the operation of the unit with the Sunnovations Ohm Monitoring system....

http://ohm.sunnovations.com/

The Ohm system is really to monitor solar water heating but I hacked it monitor the Nyle. I get great information about my Nyle performance....top of tank temps, input and output temps, graphs of enthalpy, etc.

Best part about the whole installation is the cost. I purchased the unit for $900, my REMC gave me $300 for installing a heat pump, and the IRS gave me another $300 for installing efficient energy equipment. My out of pocket was only $300.

[bcroe]

I use a Nyle system. I only run it during late spring, summer and early fall. It is also on a timer so that it only operates during daylight hours. In the warm months it will use ~50 to 60 kWh per month and generate most of our hot water requirements.

Very efficient and quiet. Since it is also rated as a one ton AC I have it connected to the cold return duct work but as you see I also installed a louver to redirect the cold air during late spring and early fall when the house is too cool for additional AC.

I see a claim of COP up to 5, impressive. Is the room supplying source air? Bruce Roe

[DanS26]

I use a Nyle system. I only run it during late spring, summer and early fall. It is also on a timer so that it only operates during daylight hours. In the warm months it will use ~50 to 60 kWh per month and generate most of our hot water requirements.

Very efficient and quiet. Since it is also rated as a one ton AC I have it connected to the cold return duct work but as you see I also installed a louver to redirect the cold air during late spring and early fall when the house is too cool for additional AC.

CIMG0870.JPGCIMG0871.JPG

[bcroe]

Finally got a prediction of 10 days with a lot of sun. Not cloudless, but this array can
deliver very substantial energy even under lighter clouds. Meter spinning today.

The propane for drying clothes, Hot Water, and leaks amounts to 271 gallons a year.
Have fixed more than 1 leak, hope that is now zero. The (now backup) propane furnace
has not run in a while. Multiplying 271 g/y by 27 KWH per gallon, and times 0.8 burner
efficiency, comes to 5850 KWH per year, my guess mostly for the HW. That in turn can
be broken into actual use and standby losses. That is more than my KWH surplus, so
efficiency improvement would be good.

The HW source is reading 105F, insulation about 82F, basement air around 70F. The
door foam may be in 60F air, other side 0F, still it does not chill the finger. No Armaflex
was used in 2004, at $1 per foot would consider that in the future. My duct tape assured
the cheap insulation would at least stay in place and sealed longer, not adding any
thermal properties.

Heat Pump water heaters probably ARE NOT the inverter driven variable speed compressor,
COP approaching 4, that my house HPs are. So I am avoiding them for now.

The temp in the attic peak needs to be monitored over days and season, to determine
just how much time it is far above the 55F incoming water. If that time is substantial,
it could be used, and be bypassed and drained for the remaining time.

For the moment, an electric water heater would at least let me consume my annual
KWH surplus and save propane, even if not a 100% changeover. A non vented
electric clothes drier would be the other item, except they are pretty small.

For the future, I need to figure out how to make the furnace air ducting easily removable,
then redesign the revealed hot water pipes for minimum length and max insulation. Not
likely this year though. Bruce Roe