Back-up power

[Troyskie]

Totally non-FJ question, and a bit of an intro to my problem...

I recently read some of the comments from Randy et al in the RPM parts update thread about power outages from the local equivalent of our Greedy Bunch of C@#ts.

I live in a rural area bordered by those pesky explosive eucalyptus trees, we are at the very end of our branch of the grid. The power comes on poles beside a beautiful tree lined road.

High wind or fires cut power pretty regularly. The family have coped with multi day power cuts, but it is really inconvenient having to get bags of ice to keep the freezer frozen, and the kids lose it when they can't 'talk' to their friends on social melodrama, or do some gaming.

I have a little 4kVa Honda petrol genset for the fire pumps, which I can use to power essentials for the house if we're not on fire.

LPG or other gas powered genset is no go for me. Diesel or petrol is the most available fuel (except for coal and that is out).

Like Randy I've been thinking of solar with battery storage.
FJ1200w mentioned UPS it got me thinking. I have several servers at work and bought a good UPS (I change them every 2 years for a new one) to keep them up long enough for a controlled shut down if the power fails (about 20 min). Been faultless.

Does anyone know of a system that uses solar battery storage with a genset charge cut-over which will operate like a UPS?

My ideal solution is one that operates like an auto/marine system where power goes from battery to system, and the battery is constantly charged from a generator/mains, and the battery+invertor etc. acts like a shock absorber from the generator/mains to the system.
This is so the power stays on when the mains cut, and the generator should kick in when the batteries drop below some defined lower limit.
I can't find one.

Troyskie

[krusty]

My eldest son lives on a property in the Pilliga north of Coonabarabran. He relies on solar charged batteries with a big gen to provide extra to run an air conditioner when required as his partner has MS. He is waiting for delivery of two new batteries from an Australian firm called Red Flow.
https://redflow.com/
Could be worth a look but they're not cheap but they have advantages over options like Tesla. They are being used as a solar charged backup for remote mobile phone towers in the event of power failure and some places in Africa where emergency back-up generators get stolen. He has fire fighting set up also. Two petrol powered pumps feeding roof sprinklers and a fire hose at each end of the house fed by a 25,000 litre water tank which is solely for firefighting. He has a second tank for domestic use.

[Pat Conlon]

Give the folks at Outback Power a shout. They specialize in off grid and grid tied systems.

[giantkiller]

Outback was one of the first to offer grid tied inverters that allowed you to use your solar system when the power went out. Now there are several. But be sure to check that the one you get. Has that ability.

I have the Pika system. 10,080 Watts.

[Troyskie]

G'day fellas,

Krusty, Pat, and Giant, great direction.

I chased down those names and found a local dude who is coming around both home and work to quote it up.
It won't be cheap, and as I don't have the quote I can't tell if I can afford it yet, but fingers crossed.

[red]

Troyskie,

I have not been keeping up with the home power systems, but even a few years back, there were a good number of battery chemistries available, not just lead-acid or lithium.  You may want to look at fuel cells, too.  They run on a variety of fuels now, and make house power with no engines involved.  Google corporate runs entirely on fuel cells, and home-sized units are commercially available.  I have no idea what technologies may be available there, but I'd want almost anything except a genset, no matter what fuel it needs.
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[Pat Conlon]

Hey Red, I would like to learn more about residential fuel cells if you have a link.

I have found several old articles with the most recent being February of this year:
https://fuelcellsworks.com/news/the-fuel-cell-powered-home-an-approaching-reality/


Cheers

Pat

[Troyskie]

Thanks Red. I will look into fuel cells. I last looked some years ago and it seemed like it would be ages before they were more commercially viable.

Regarding the genset, that is the final bit of redundancy in the system for when all else fails.

[red]

Hey Red, I would like to learn more about residential fuel cells if you have a link.
I have found several old articles with the most recent being February of this year:
https://fuelcellsworks.com/news/the-fuel-cell-powered-home-an-approaching-reality/
Cheers
Pat

Pat,

All of my research is old now, so you would do better with new Searches.  I heard a Canadian outfit was selling them in California, and China has all sizes available.  Some run on hydrogen (which you can crack for cheap from water and solar, or check out the new hydrolyzers).  Some fuel cells run on the standard piped-in natural gas, or LNG from tanks.  The house fuel cells are about the size of a clothes dryer, maybe as large as a refrigerator, and the hydrolyzers are a little smaller.  Home fuel cell prices were running ~US$8k, but that may be better by now.  Most off-grid power systems are being sold for the same money that you were paying to the power company, but the payments stop after you have paid it off.  A guy in Denver was cracking hydrogen with a standard homestead windmill.

[Pat Conlon]

Our electrical utility in SoCal is an Investor Owned Utility (IOU) and as such, needs to make a profit every year for the stock holders in the company. A minimum dividend of 6% is needed to return to investors to keep the rats from abandoning a sinking ship.
The newest scam to defraud the customers is charging electrical rates based on time of use.
Proposed are 3 rate time slots, 1) On peak: 2pm-8pm @ $0.34 per kWh 2) Mid peak: 10am-2pm and 8pm-11pm @ $0.22 kWh and 3) Off peak: 11pm-10am @ $0.12 kWh

In my desert climate zone we need air conditioning in the afternoons and evenings. No way around it. Gotta have it. The building envelop is important, High Efficiency a/c is important, but even with that we are going to get absolutely screwed with these new time of use rates.

Here's a couple of things I'm looking at to shift the load off the $$$ on peak rate:
https://www.shoptinyhouses.com/products/humless-home-standard-6-5-generator
The built in 3kW inverter can feed in PV power (if I wish) or if I don't have any PV panels, just plugging in the unit and charging the lithium batteries at night @ $0.12kWh and set the unit up to discharge the power durning the 2pm-8pm time slot so I don't get charged the outrageous rates by my IOU.
This is a very small 6.5kWh combination battery/inverter unit simple to install.
A more cost effective choice would be the larger Tesla Power Wall @ 14.0 kWh for about the same price.
Used just for load shifting (saving $0.22kWh) it's about a 7.2 year simple payback, based on $1,124 year one savings with a $9k installation cost.
The $1,124 year one savings will increase as the IOU increases the electric rates, averaging 4% per year increases. e.g. year two: $1,169 savings, year three: $1,215, year four: $1,264, etc, etc...

On second thought...I think I'll wait on the batteries for now with newer higher density stuff coming on line.


My point is, everybody's condition is a little different. It is best to get an proper evaluation from the experts.

I'm a big fan of Out Back Power.
Leave it to an Australian company to show the Americans how to design, build and install off grid and grid tied systems.

[red]

On second thought...I think I'll wait on the batteries for now with newer higher density stuff coming on line.
My point is, everybody's condition is a little different. It is best to get an proper evaluation from the experts.  I'm a big fan of Out Back Power.   Leave it to an Australian company to show the Americans how to design, build and install off grid and grid tied systems.

Pat,
One alternative there might be cheaper; low energy-density batteries, and a lot of them.  Saw one new technology being developed that uses salt water.       Made me think of Jules Verne's Nautilus batteries (I think we have enough seawater).

I had the opposite problem; in Utah, USA, the winters are Polar.  I found a guy with an "in" for clean fill dirt.  He rented a BobCat, and installed earthwork berms all around my house, almost as high as the foundation/brickwork line.  We used a Ditch Witch to dig a very narrow 6' (2m) deep trench all around the berms.  We covered the berms with sheet plastic (the type of plastic which never decomposes underground).  We ran the plastic sheets down from the foundation wall, down the berms, and to the bottoms of the ditch.  He then added enough dirt to the berms to hide all of the plastic, and grow my ground-cover plants.  It was all done before dinnertime, in one day.  It cost me US$100 for the dirt, US$75 for the BobCat, and US$25 for the rolls of sheet plastic.  Why?

The ground never freezes here below 3' (1m) deep.  At 6' (2m) down, the ground does not get much below 50 degrees F (10C) in winter.  The earth under the plastic loses all moisture, and becomes a dry brick worth of insulation; I had a yard (meter) or more of it, all around the house.  The earth under the plastic sheet stays at the same temperature as the earth at the bottom of the ditch.  Basically, I took the bottom half of the house (the coldest part) to about halfway to the Equator.  The basement never freezes now, and for US$200 invested, I pay about half of the heating bills that I once paid, now and forever.  If you want a fancy name for the project, this is Passive GeoThermal Heating; heat is taken from the Earth into the house for cheap, with no maintenance, no pipes, and no moving parts.  The house looks very normal outside; no neighbors even notice it.  BTW, this same project also cools the house in summer now; that's free, too.    

By comparison, insulation and a stud wall with sheetrock, all around inside the foundation, would have cost me over US$5000, and done nothing more.  That would be IF I did all of the work myself.    
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[Pat Conlon]

Thanks Red, that was very interesting. I've been a desert rat for so long I forget what folks have to do to keep heat within their homes.

A funny story about a friend of mine who was an a/c contractor. Joe was building his dream home and he wanted to get away from the inefficiency of an air cooled a/c condenser. We know that when it's 115* outside a 5 ton rated air cooled condenser will give you only 3.8-4.0 tons of cooling capacity. A water cooled co-axial unit was out of the question with the cost of water these days. So Joe decided to install a ground source heat pump aka Geo-thermal heat pump.
When it's 115* outside, 6 to 10 feet down it's much cooler ~78*. Joe dug down 15' and installed the copper condenser coils. He was worried about a rock puncturing the copper tubing so Joe used clean washed sand for his backfill.
He finished his home, moved in and his first summer electrical bills were crazy expensive. His multi speed Carrier high efficiency systems struggled to keep his house cool. He put his gauges on his system and it showed the compressor's head pressure to be dangerously high. His system was absorbing the heat in the home but not shedding the heat underground. The same symptoms as what happens when your outside condenser fan stops working, except Joe's system did not use a condenser fan. He kept access to bore hole 20' deep so he could monitor the underground temperature and yep, the underground temperature was still nice and cool.

His mistake: Joe used clean washed sand as a backfill to his coils. This washed sand had a very high silica content. The silica is a very effective insulator which was preventing the heat transfer from the hot coils into the cool earth.
Good news was that in his wisdom, Joe did not build any structures or concrete decking over the ground loops. Bad news was he had to carefully dig down and excavate all the silica sand away from his copper coils and replace it with pea gravel. Problem solved.
A very expensive lesson right there. Proof that the devil's in the details.

Cheers Red! Thanks again for the tip!  Pat

[T Legg]

I have worked on several ground scource heat pump systems over the years that the ground scource has failed over time.most were horizontal a few were vertical.The constant heating cooling of course causes expansion and contraction of the soil causing voids to form around the pipes and poor heat transfer.On one system that was only used for cooling I installed a small five ton fiberglass cooling tower.water usage wasn't any worse than a normal swamp cooler and water returning from the cooling tower was easily maintained in the sixtys or lower.I had a customer who manufactured PVC pipe and used two seventy ton chillers to cool their process water.I installed a two hundred ton fiberglass cooling tower to directly cool the process water and easily maintained water in the sixtys.I charged them $28,000 installed(back around 1999).they never used the mechanical chillers again.The first year they saved $ 92,000 in electricity.

[Pat Conlon]

Our local mall has 60 ton roof packs air cooled as part of their VAV system. Straight cooling, no heat. The building heat was provided by the lights and occupants.
Anyhoo these big air cooled roof pack a/c units struggled in the summer when roof surface temperatures exceeded 130*+, along with cooling down the required cfm's of Outside Air needed for occupancy ventilation.
To assist these roof packs in handling their cooling loads the mall installed these big barrel shaped evaporative pre-coolers to get the compressor head pressure down.
Unfortunately the precoolers lasted only for 3 summers before they ended up removing them.

I used to love evaporative cooling in my home. Turn on the cooler, crack the windows open, and get cool fresh air through out my house. Very cost effective using a 2 speed 1/2 hp evap.cooler fan motor vs an old 10 SEER 5 ton single speed central a/c system.

I've noticed in the last 5 years or so that the humidity in the desert has risen to a point that my cooler no longer works. (Need below 20%RH) The summer days are getting more and more humid, most over 30% RH.

I've also noticed that in the last 2 years my 21 SEER variable speed compressor, when the system is on low speed, uses the same amperage as my old evaporative cooler.  
These new Mitsubishi mini split systems are the bomb. 1 condenser can handle 4 air handlers, each with their own individual room temperature control.

Central a/c with its leaky duct work is dead. Why cool the whole house?

[racerrad8]

I've noticed in the last 5 years or so that the humidity in the desert has risen to a point that my cooler no longer works. (Need below 20%RH) The summer days are getting more and more humid, most over 30% RH.

Not just the So-Cal desert, we are experiencing the same thing up here in the Nor-Cal valley. Today the temp is going to be 100 and the humidity is expected to maintaining at the 30%+ mark. I don't mind the heat, it is the humidity that makes it uncomfortable.

Right now, the weather say 94 degrees and a "real feel" temp of 99 due to the 32% humidity level.

Randy - RPM