My Solar PV journey is officially ending

[EastTexCowboy]

All the energy conscious Texans (and most are not) care about is SEER. And that's find normally, a snap of more than 2-3 days below 30 is very unusual. But when it hits, many of these units (including mine) cannot produce heat worth a crap via pump.

It depends on the brand and model. The ones I have are 100% efficient down to 5 degrees F. I think it was @SolarScott who did a video of his at something like 4 degrees and it was still toasty in the house. The standard heat pumps though, are only good down to about 30 degrees.

 

[EastTexCowboy]

Your heat pumps would have kept up. Whatever you have is not standard in "builder grade" construction in Texas, nor are people "cold weather performance" concerned about HVAC. Most people have no clue.

And I'm assuming "kept up" means they would not have kicked into resistive / emergency heat.

Mine don't even have heat strips installed. But no, they are not builder grade. I think a lot more people are concerned about cold weather after the last few winters. But to each his own.

 

[1201]

You can use a cheap inverter and cheap bypass mechanism to just run your base loads. The battery doesn't need to be sized for additional run time, just to stabilize the inverter as a cloud front comes through. You size the bank at about 2kWh(nominal)/kW PV; AGM batteries (even used) can do the job.

But, your best payback is likely summer awnings to shade the house more.

The sun is high in the sky in summer and it's only 400sq ft of windows who needs shading? ??


My base loads are too little to make a solar system make sense. If there was a bypass mechanism they could switch back to grid at dark , daily, and turn off the inverters, that's something that would work but afaik, that doesn't exist

 

[1201]

For folks that are on grid ... a "backup" system seems of high(er) importance. No matter where I lived in TX, CO ... outages happened, and for the strangest reasons. These range from brownouts & other fluctuations to full blackouts.

A small parallel inverter/battery-bank/panel-less system w/ small inverter-gen as backup can ride you over any scale outage, as the system is:
- recharged from grid after small outages
- recharged from small inverter-gen during longer outages
- automation can make it easy to operate, if components well-integrated

During a long outage (several days), the recharging gen would run no more than 4 hours in 24 or thereabouts, as it is the battery-bank getting you through the outage. Add propane as a site-fuel, and no messy fuel effort; plus, other devices can be propane.

Whole-house gens are in the $5k on up range, installed, and that buys a lot of the "off-grid" or parallel solution. I've seen them get into the $10's, and then there's issues of reliabilty & service for gens of this size.

At this point, the comparison isn't "payback", it's "is there a backup in place" for an outage, making it a critical system (vs sitting in the dark). You want "buffers" in place for everything ... a 250-gallon buffer in the water system, a parallel power system for your grid power, etc. It's not how things are working now, or in the past, it's what will happen that you didn't think about, and these are legion.

Hope this helps ...

I can't remember an outage longer than an hour since I've lived here but if we some that outages will become more common then the backup system you described would be very advantageous, but that would be a fairly big assumption

 

[labeeman]

The Texas grid is it's own political entity.
Unfortunately, MOST of Texas is on electrical power for heat and our heat pumps are NOT designed cold weather efficiency, so they eventually move to resistive heat - which is massive power draw and that strains the grid.

It failed in 2021 due to failure to winterize natural gas lines that were there to spin up turbines and high heating demands.
Many local failures in 2023, the overall grid was fine but local providers failed to handle trees / power lines that became burdened with an unusual amount of ice. Most of the outages were local transmission related.

In both cases, some people lost power for 1-2 weeks. It was a S-Show.

I have a ground source heat pump and it does not care what the outside temp is as the water is a constant 72° f with a COP of 4 the newer units have a higher cop.

 

[1201]

I have a ground source heat pump and it does not care what the outside temp is as the water is a constant 72° f with a COP of 4 the newer units have a higher cop.

Ooh I heard those can cost 30-60k installed?

 

[labeeman]

I went with solar due to the green movement I now enjoy a rate of $0.14 but if they cut off coal that figure will be much higher some power companies here are almost double that rate here already and it is my hobby. I am also in hurricane country and even a generator has problems if you cannot get fuel due to gas stations not being able to pump.

 

[labeeman]

Ooh I heard those can cost 30-60k installed?

I installed mine over 20 years ago and now your price would be about right the unit itself is about 3k now it is the water loop that is expensive I have 4 200ft vertical wells for the loop.

 

[J.H.]

or at least going on a very long Hiatus.

So I built a passive solar house- the roof is 35° slope facing 4° west. no penetrations, no shading. I built it to be perfect for solar panels.

https://imgur.com/a/hFKDZKx

BUT, net metering ended two months ago before I could get in and I have spent the last two months trying to make solar with batteries make sense, and I have finally come to the conclusion that, right now, I cant.

energy averages $.11/kwh, down from $.14/kwh last year.

In the winter my house will use very little energy for HVAC, which is the main load for houses here my part of Texas. with no hvac system, on sunny days the house sits about 75 degrees due to all the radiant heat coming in through the south facing windows.

If I get 10 years out of an inverter and 6000 cycles out of the battery, I basically break even.

you guys are a fun but crazy bunch who persist through headaches of solar, and from reading on here, they are many. I don't have the patience to deal with all that comes with Solar PV and batteries

I have decided to do three things.
1. Wait for energy prices to go up and for battery
and inverter prices to come down
2. use a clothes line to dry clothes and save money there
3. Use a cheap diy Solar THERMAL hot water system to heat my water.

however, I still have a decision to make about backup for my well pump. we hardly ever lose power and I have 25 gallons of reserve in the pressure tank but if we have a freeze we could lose power for over a day. I'm going between an inverter/ battery , or a generator, and frankly the generator is winning right now :D

As far as water goes , I bought. 350 gallon potable plastic water tank…10 years ago … it’s made to fit snuggly in the back of a USA standard pick up truck…weighs about 2800 lbs full. put a 10 dollar hose tap in the side near the bottom…bought a 89.00 Shureflo 12 volt water pump…and some white hose.. hook it to a tap on the cabin or the RV…yer done ..!
make it a diaphragm pump …not impeller..
mine still is great after 10 years and a few thousand gallons of pumping.

thats it about ..about 400 .00 Total
i have used it so many times to feed my Rv in power down situations out on my land both summer and winter.. easily lasts a week living good and much longer if conditions require it…
It weighs about 50 lbs empty and can be handled by one man and filled up about anywhere there is a water supply while in the truck…then bring it home..that’s it..
if your ever without water you will appreciate how much water 350 gallon is… it’s huge..

PS. 12 drops of Clorox per gallon if you acquire well water or iffy sourced water ( not city) and it’s easily safe at least a year …if used quickly ,forget the Clorox , as that is for long term storage…or purification.
we have all become spoiled with how much water we think we must have…A shower , dishes , cooking, cleaning ..every day from a tank for a week… I can live with that if I have to…

 

[50ShadesOfDirt]

You've been extremely lucky, if:

- a street transformer never blew
- trees/branches/ice never took out a line
- cars didn't crash into a pole
- weather events (tornados, hurricanes, deep freezes, heat waves, etc) didn't affect some or all of the overall system

... such that it didn't affect you directly. That's just the normal, visible stuff, and grids will react to it, and get it fixed sooner or later. BTW, did anyone read their grid contract lately, or the contract that the grid operates under with the PUC of the state? There's stuff in there that makes you want to have a backup source of power.

The invisible stuff is power quality ... sags, surges, brownouts, etc. Any grid has this, and most people won't know about it because they don't monitor for it, or it happened when they weren't doing something at that moment.

And then there's just the weird stuff you would never imagine ... someone shoots a critical transformer out, or the meth lab down the street blows up, or a wildfire took out entire neighborhoods because the weather aligned with an idiot and a fire ... or a train derails, or a hazmat hauler flips over, or ...

This is just electricity ... but one system of many. Water went out often enough as well, and we always played the game of "fill the tub, or don't fill it" ... are we feeling lucky today? We hardly ever got it right ...

Now, we have buffers for every system. Backups for every system. Technology makes it possible, and easy ...

 

[rhino]

I find it that as @50ShadesOfDirt showed most people seem to neglect all the hidden costs/risks of relying on grid power. It's no different than any other "insurance". You might only realize how important that insurance is when you need it the most.

There could also be other tangential damage from grid power such as bulldozing/clearcutting under power lines, wild fires started from trees hitting power lines, etc.. Both of those have happened to lines connected to me.

 

[dcg9381]

I have a ground source heat pump and it does not care what the outside temp is as the water is a constant 72° f with a COP of 4 the newer units have a higher cop.

I think this is geothermal, right? It's not the heat pump type that I'm discussing that is present in most of Texas. I've never seen geothermal heating in Texas. Seems to be a up north thing.

 

[Zwy]

or at least going on a very long Hiatus.

So I built a passive solar house- the roof is 35° slope facing 4° west. no penetrations, no shading. I built it to be perfect for solar panels.

https://imgur.com/a/hFKDZKx

BUT, net metering ended two months ago before I could get in and I have spent the last two months trying to make solar with batteries make sense, and I have finally come to the conclusion that, right now, I cant.

energy averages $.11/kwh, down from $.14/kwh last year.

In the winter my house will use very little energy for HVAC, which is the main load for houses here my part of Texas. with no hvac system, on sunny days the house sits about 75 degrees due to all the radiant heat coming in through the south facing windows.

If I get 10 years out of an inverter and 6000 cycles out of the battery, I basically break even.

you guys are a fun but crazy bunch who persist through headaches of solar, and from reading on here, they are many. I don't have the patience to deal with all that comes with Solar PV and batteries

I have decided to do three things.
1. Wait for energy prices to go up and for battery
and inverter prices to come down
2. use a clothes line to dry clothes and save money there
3. Use a cheap diy Solar THERMAL hot water system to heat my water.

however, I still have a decision to make about backup for my well pump. we hardly ever lose power and I have 25 gallons of reserve in the pressure tank but if we have a freeze we could lose power for over a day. I'm going between an inverter/ battery , or a generator, and frankly the generator is winning right now :D

Here is how I decided to go with batteries instead of a generator. https://diysolarforum.com/threads/ground-mount-installation-questions.60001/post-744519

Once you get a system up and running, you will wonder why the heck you didn't do it sooner.

 

[labeeman]

I think this is geothermal, right? It's not the heat pump type that I'm discussing that is present in most of Texas. I've never seen geothermal heating in Texas. Seems to be a up north thing.

Yep, I am about 30 miles north of the Gulf of Mexico.LOL It is used here for cooling as it is the most efficient cooling there is as it uses 75° water for the condenser instead of 100° air.

 

[TorC]

On thermal hot water mentioned earlier in the thread: if you can set up a thermosiphon system, with or without a refrigerant heat exchange system as needed, those systems will often run just about zero maintenance for decades - as I know from my dad who got reports in the last couple years of systems he installed in the 70s working just as well as when new. The materials are mostly basic, easily recycled materials, not highly refined arrangements of rare materials. A far better option environmentally IMHO. I wouldn't even try to claim the PV system I've got is green like that.

 

[ADDvanced]

You can’t believe everything you hear.

Yes I can. It's not hooked up to the rest of the grid. Which is stupid.

 

[1201]

On thermal hot water mentioned earlier in the thread: if you can set up a thermosiphon system, with or without a refrigerant heat exchange system as needed, those systems will often run just about zero maintenance for decades - as I know from my dad who got reports in the last couple years of systems he installed in the 70s working just as well as when new. The materials are mostly basic, easily recycled materials, not highly refined arrangements of rare materials. A far better option environmentally IMHO. I wouldn't even try to claim the PV system I've got is green like that.

What do you think about a setup like this?

https://imgur.com/a/8Csrvb7

 

[JJJJ]

For us it was never about cost effectiveness or break even points. It was for piece of mind if the power goes out.

Most importantly my wife likes the idea and fully supports my project ? which is a big win for our situation.

Fully respect your decision however. Shows a great deal of thought and consideration.

 

[TorC]

@1201 Pumped systems like that work, but there's always a bit more that can go wrong with them. I'd still install one if it was what I had to do for the hot water. The differential controller is essential, because even a DC pump on direct PV will respond differently to conditions than the water panel. I've tried the latter, and it never behaves right, even though you'd like to think it would be perfect.

 

[1201]

@1201 Pumped systems like that work, but there's always a bit more that can go wrong with them. I'd still install one if it was what I had to do for the hot water. The differential controller is essential, because even a DC pump on direct PV will respond differently to conditions than the water panel. I've tried the latter, and it never behaves right, even though you'd like to think it would be perfect.

I've been watching some videos on thermosiphon systems and they actually work very well. No pump needed which saves upfront cost and maintenance , and no controller needed. Could save quite a bit of money.

I'm going to look into those a lot more. Thanks

 

[HarryN]

For us personally, a power outage is not unusual and now kind of expected every year during fire season.

So we can loose a lot of frozen / refrigerated food in just a few days. It actually isn't so much the value of the food itself, but the time spent dealing with it and my wife takes the brunt of this in trying to shop for it all again.

If the power is out for us, it is out for many, so the food distribution system can be unstable for a while.

The fuel that we can purchase locally is not stable enough to store in any significant quantity to run a generator very long.

So my focus is to power the refrigerators via solar / battery 95% of the time, and use the grid to back them up.

This is quite a bit less costly than trying to compete with grid pricing.

 

[S610]

Interesting. Is there a reason you went with passive heated instead of passive cooled for that area? Wondering since I think of Texas as hot.

I am planning a passive cooled off-grid home in Georgia which means lots of air flow, deep covered porch, operational transoms and a whole house fan so I won't need A/C at all under normal circumstances. Won't do jack to provide passive heat but that is less of a concern in this climate. A wood stove would do in a pinch if the power was out completely (and the house can stay livable without power in the summer too).

 

[1201]

Interesting. Is there a reason you went with passive heated instead of passive cooled for that area? Wondering since I think of Texas as hot.

I am planning a passive cooled off-grid home in Georgia which means lots of air flow, deep covered porch, operational transoms and a whole house fan so I won't need A/C at all under normal circumstances. Won't do jack to provide passive heat but that is less of a concern in this climate. A wood stove would do in a pinch if the power was out completely (and the house can stay livable without power in the summer too).

Great question. I have a "passively cooled" house currently and it was a mistake. My current house has a bright white roof and bright white exterior walls and no south facing windows. It doesn't get nearly as hot as other houses in summer, but also doesn't get nearly as hot as other houses in winter. In other words it's stays COLD in winter.

North Texas is actually as hot as it is cold. We have approx 2500 cooling degree days and approx 2500 heating degree days.

The mistake I made was I currently have electric resistance heat which is not as efficient as cooling with an ac so my winter electric bills are higher than my summer bills.

With the new house I think I have a little bit of both. The white roof will keep the house a little cooler in the summer and the windows keep it nice and warm in winter. I put on 90% solar screens in mid April and take them off at the end of October so I get the best of both worlds(in theory)

I don't know how hot your summers get but if it's over 90 a fan isn't going to cut it. Too much humidity at night and too hot during the day.

Unless of course you are doing high thermal mass where you build the exterior walls out of thick concrete

 

[J.H.]

For us it was never about cost effectiveness or break even points. It was for piece of mind if the power goes out.

Most importantly my wife likes the idea and fully supports my project ? which is a big win for our situation.

Fully respect your decision however. Shows a great deal of thought and consideration.

You are correct.. I won’t live long enough to receive a ROI on what my solar , water and heat investment has cost…but I will have what I want and need while I’m alive without hoping somthing bad doesn’t happen to limit access to those things…It’s called self dependence …
there’s a few other things I have covered too, but we will just skip that..

 

[RV10flyer]

Understandable. Solar, depending on grid availability and cost, can be uneconomical to put in. It has no real pay back where I live with low fixed electrical rates. In my case I dabble in it for reasons that are not to save money. I could spend my money on wine, women and song but at my age I gave up drinking, women are hard to acquire and expensive to maintain and I never could carry a tune. So I am left to find other things to occupy my time.

Always been fascinated with making things work. It is a great deal of satisfaction to power the lights, cook my dinner, watch my TV from power generated from my own setup solar power supply. Even if it cost more than simply buying it from the Co-Op.

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