Installing a Solar Energy System

Resilient Life Public Resilient Life
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21

There are MANY ways to build solar water and air heaters for less than $100.
The complexity of this system is scary, how are you going to FIX it?

I really do like the house, it’s just too bad it can’t be turned around.  I would definitely CHANGE a few things to use the sun for heating.  A real adobe addition on the south side would go a long way.  I would also install a false ceiling for winter. 

Why not simply leave the recessed lighting off?   Light fixtures are CHEAP! 

We’ve been living off the grid since 2007 in our still unfinished house (convential framing) and we’re still working on many changes.  Unfortunately I didn’t learn about adobe until AFTER the exterior was finished.

We have LED lights (they work with dimmers) and they’re perfect to provide enough light so you find your way around at night.  We leave them on in the hallway until we go to bed.  We have multiple light fixtures with different bulbs in each room, but of course one can get one of the plugin types without having to do any rewiring.

We added a little greenhouse on the south side built with adobe.  It’s incredible how cool it stays in summer and that it always stays over 40 degrees even with single digit temps at night without any heating.

Today we’ll hopefully finish our first solar air heater and we’ll test it on the greenhouse addition.  If it works, we’ll put vents from the addition to the house to help with heating there.

Cost: about $15 for lumber and a sheet of OSB (which we’ve already had for a few years).   For glazing we’re using some old windows we recently got free.   It’s not nearly as pretty as what you buy at a store, but consider the savings!  

We’ve been watching online videos on how to make all sorts of solar water heaters and air heaters. Especially PREHEATING water for regular water heaters is extremely cost effective.  But don’t bother trying to make you own solar electric panels and don’t pay for any of the ebooks that claim that it’s so easy.  It’s a ton of work and you don’t save much.

It’s a shame that so few builders consider free energy - our sun.  But as long as you have unshaded space on the south side of your house you should definitely look into SUPPLEMENTING with solar.  It’s very inexpensive and even people in apartments with sunny windows or balconies can lower their utility bills.

Reading this article is like watching a TV show about the houses of the rich and famous.  It works for THEM, but the average person couldn’t even pay the property taxes and maintenance.  Similarily, I know that we could not afford to maintain such a high tech system.  It’s NICE, but not for us “little people.”

I really wish I had known what I know  now a few years ago, but it’s never too late to learn and make some changes.

Christine

 

22

we_are_toast,

I don’t know about not having much skill.  Building a house (and one off the grid for that matter) is quite an accomplishment in my book.

I like what you’ve done.  It’s simple but well thought out.  The older I get, the more I appreciate the virtues and benefits of simplicity.

I have a couple of questions, if you don’t mind.

Any particular reason (other than cost savings) that you built the house on a slab in a cold weather area rather than building a basement?

Is that a metal roof?  If so, knowing how snow slides, any particular reason you built the garage doors on the front of the house rather than the side? 

What type of siding did you use?

Is that a propane tank I see and if so, what percentage of your  does it supply in the winter?

Thanks for any help and for your fine contribution.  I, personally, would like to hear more about your house and your ideas.

 

23

[quote=rhare]
Sorry for the delay responding, have family in town for Thanksgiving so I’ll try to respond to all the questions and comments so far.

[quote=Damnthematrix]“It may be that the incremental cost of a larger solar installation will be less expensive than usage reduction improvements you can make”

In my experience…  NEVER.[/quote]

It’s funny Mike,  when I put that in there I was guessing you would be the first person to make a comment. Never say never! So let’s look at some systems over a 10 year ownership, all these systems with grid tied SMA inverters, Schott 225 Panels, 50% of the material cost added on for installation (assuming cheap roof mounts):

  System Size
  1kW (.9) 2kW 2.7kW 3.6kW
         
         
         
Total 5,095.50 9,928.50 13,396.50 17,577.00
         
Yearly Power Production (from PV Watts) 1,513 3,363 4,540 6,053
         
Total (less tax credits - 40%) 3,057.30 5,957.10 8,037.90 10,546.20
REC Credits ($0.13/kWh - 10 yrs -1,966.90 -4,371.90 -5,902.00 -7,868.90
Power Savings ($0.08/kWh) -  10 yrs -1,210.40 -2,690.40 -3,632.00 -4,842.40
10 year cost -120.00 -1,105.20 -1,496.10 -2,165.10
 
So Mike, here in NM, with the incentives currently in place:  you're better off, over the next ten years, building the largest system you can.  The larger the system the better the payoff.  .[/quote]

You’re not telling me anything I don’t know here…  I do this for a living.  We are talking at cross purposes here.  I wasn’t saying that building a bigger system won’t save you money (or even make you money), I’m saying it’s ALWAYS cheaper to find ways to reduce electricity consumption than to generate your wastage by any means, whether coal fired or PVs, but especially PVs.

In the last 12 months we have reduced our consumption (according to the last bill I’m holding in my hot little hand) from 4.98kWh/day (an already very low level of consumption) to just 2.13kWh/day…

How did we achieve this?  With a hyper efficient fridge that only cost us $700 (it’s in my blog - link below), switching from satellite internet to ADSL (the old modem consumed 60W continuous, the new one so little we never bother to turn it off), switching from a 130W PC to a 30W laptop, and ditching the old 150W CRT TV to a 50W LCD digital unit (only 23")

If you’ve been following anything I write about what we’ve done, you’ll know we’ve had 1.3kW on the roof for over 5 years, and that we have recently added another 2.2kW - just as an investment.  Both systems are now feeding the grid through a SMART METER.  We get 52c/kWh for any excess (ie that which we don’t use, which is like 90%) and only pay 21c for everything we import (like at night).

The result is that we will make ~$2000 a year profi out of this, which is MORE than what you will make out of your system which is three times the size of ours.  Now tell me energy efficiency doesn’t pay?

Yes it is rather cool…  I only found it three days ago, and it was love at first sight!

3Es or no 3Es…  there’s no excuse for building the crap housing stock currently going up all over the world.  I’ve known about building truly amazing houses for twenty years, so why doesn’t anyone build them…?  Sigh…

Mike

24

[quote=ao]DTM,
I like the house in the Swiss Alps.  My only question would be,  what about snow accumulation?. [/quote]

There are pics of it in snow here http://www.christian-muller.com/CMA.Projects/VVW/180-ArchRecord.pdf

Mike

25

Thanks for sharing pictures of your system.  I was a bit worried that it would scare people as well, that’s why I pointed out that the systems are scalable to any size house.  Our house is large and not designed with energy efficiency in mind when it was built (we didn’t build it).  If you have a smaller house, or are building and design with energy issues in mind you can definitely get by with a much smaller and less expensive system but the basics of how it works should be about the same. 

The systems needed to support a house will be roughtly proportional to the size of the house. For example, for heating, you have 1800 sq. ft with I’m guessing 8’ ceilngs based on the picture for a total heated volume of 14,400 cubic feet, we are heating roughtly 5 times the volume with our system. On the radiant floor heat, our house was designed with a convential boiler, so the radiant floor doesn’t work well with water less than about 140.  As you said, if you have a well insulated slab, proper radiant piping (even, fairly close runs, and close to the surface of the concrete and well balanced zones), you can get away with lower temperatures.  Our house has actually been a bit of a problem child for the controls folks because of the radiant floor was not designed with lower temperature solar in mind. The radaint floor/indirect water heater are pretty much identical to what you would find in many houses without solar.  The solar simply adds another heat source.  If you happen to try to do dual fuel (electric, gas, wood) heat sources you would probably have a very similar setup.

I’m guessing with your PV, wind, and being off grid, your PV setup may actually be more complicated than our system. 

[quote=Christine Baker]There are MANY ways to build solar water and air heaters for less than $100.

The complexity of this system is scary, how are you going to FIX it?[/quote]

There are always ways do do things on the cheap as a DIY.  However, in the case of cheap hot water systems and air systems they have their limitations.   With air systems, you only get hot air during the day, and little to no heating at night unless you are using hot air to heat a mass.  However, if you are trying to do that, a thermal hydronic solution is much more efficient and will require less collector surface area.  Cheap water heating systems are easy to build in climates without freezing temperatures, but once you get freezing it complicates things a bit.  You either have to drain water out of collectors or use a separate loop filled with antifreeze (glycol) and a heat exhanger (exactly what our system does).

The system is not very complex and I feel I could easily work on any of the components with basic plumbing skills.

We could, but I don’t want too.  It would seriously impact the aesthetics of the house. Wink  It’s kind of like why do you want windows in a house -  without any you can really cut down on your heating bills - but would it be as pleasant to live in?  On the LED lights, they have become better and cheaper recently.  There are now some recessed can replacement lights by  Cree that have the same light quality as a traditional halogen 75W bulb and work well with conventional dimmers   The problem is they are still very expensive ($75/bulb).  I tried CFLs in some areas and they are not near as pleasant a light source so I’m waiting a bit to see if the price will come down and I will look at replacing the halogen lights we now have.  Then we will have excess power for an electric car/motorcyle.  I’m also much less worried about excess generating capacity from the PV.  In an energy crisis, having excess power to use or sell will be a nice problem to have.

I actually anticipate very little maintenance. Clean off the panels and collectors once in a while and change the thermal glycol every 5 years or so.  That should be all the maintenance.   The thermal system is really not any more complex than our old radiant floor/DHW system.

[quote=DamnTheMatrix]

I do this for a living.  We are talking at cross purposes here.  I wasn’t saying that building a bigger system won’t save you money (or even make you money), I’m saying it’s ALWAYS cheaper to find ways to reduce electricity consumption than to generate your wastage by any means, whether coal fired or PVs, but especially PVs.

…

The result is that we will make ~$2000 a year profi out of this, which is MORE than what you will make out of your system which is three times the size of ours.  Now tell me energy efficiency doesn’t pay?

[/quote]

Cheaper - but not better financially. As shown, you could save money by conserving, however, if you have money that is sitting in a bank account, you would be better off spending on a larger solar system and making more money than you would keeping it in the bank.  Also, depending on the incentives rules, it looks like that would be even more true in Australia.   With the dollar at parity, your electric rates are 2.5 times more than ours and your incentive is 3.5 times more.  With incentives like that I would be building as big a system as I could!  After all, if I can invest  6000 and have it paid off in only 3.4 years and the rest of the 25 year life is income, why wouldn’t you do so? 

[quote=DamnTheMatrix]The result is that we will make ~$2000 a year profi out of this, which is MORE than what you will make out of your system which is three times the size of ours.  Now tell me energy efficiency doesn’t pay?[/quote] Actually our system has a net return of about $4,350/year. Savings on power purchases is $1,800 of that, the rest is REC credit incentive.

[quote=DamnTheMatrix]3Es or no 3Es…  there’s no excuse for building the crap housing stock currently going up all over the world.  I’ve known about building truly amazing houses for twenty years, so why doesn’t anyone build them…?  Sigh…[/quote]

Same reason very few people know about the 3Es or fiat currencies. The way I see it, the houses are built, it does no good complaining about how crappy they are or how it would have been better … It’s now a situation we have to live with and you make do with what you have and hope to influence better designs going forward. While that house in the Swiss country side is nice looking, built into the side of the hill, as far as a sustainable option I suspect the house we_are_toast built is much more sustainable/realistic for the future. Although with a mostly underground house you can start to work with seasonal thermal stores.

DamnTheMatrix, we_are_toast and Christine Baker - you should definitely work on posting the solutions you have developed and show costs and labor involved.  I’m sure many of the readers here would like to see the performance and cost information on your systems. 

26

When I say I’m not very skilled, I really mean it.  I’m not a carpenter or a plumber, or an electrician, but if you read a lot of books, and talk to a lot of people who are skilled, and you keep it simple, you’ll be amazed at what you can do.  Another big help was our county building department.  Inspectors can be a real pain sometimes, but if you talk to them before you do something, and show them exactly what you’ve got planned, they will often make suggestions that will make it easier and will meet the code without any problems.

I’m not saying building yourself isn’t a lot of work, it most certainly is.  But if you know it’s going to be a lot of work, you can plan accordingly, and it can be a very satisfying type of work.

You have some excellent questions.

I didn’t build a basement for a couple of reasons.  One was the cost.  Instead of a deep foundation and footings below the frost line, I went with a very shallow footings, approx 2 feet, and a frost protected foundation.  A frost protected foundation consists of sheets of Styrofoam that extend 4’ horizontally  from the top of the footings.  The second reason was the thermal mass.  I wanted a large thermal mass and using the floor was an easy way to get it.  The sand and concrete give me approximately 30 tons of thermal mass in the floor.  This means when it’s 0F outside, the temperature inside will drop about 8F over a 24 hour period.   On an average January day, if it’s sunny, we’ll go 24 hours without using any auxiliary heat source.

 Yes, it is a metal roof.  The area I live in is very, very windy.  It’s not uncommon to have 70 and 80 mph winds.  The winds are primarily from the southwest, so the garage doors face away from the wind.  Most of the time, the snow will blow off the roof.  When it doesn’t, I get my daily exercise shoveling snow.

The siding is hardy plank fiber cement siding.  Colorado is currently undergoing an environmental catastrophe.  The winters simply don’t get cold enough anymore to control the pine beetle.  I’ve watched about 90% of the trees in our valley die in the past 3 years.  We are keenly aware of the potential for fire.  Although a log cabin in the mountains sounds rustic and romantic, I’m betting my metal roof and fiber cement siding will mean my house will be one of the few left standing after a fire.

We have a very small wood stove we use to supplement the sun for our heating.  The propane is used for water heating and for cooking mostly.  We also have a propane fireplace with a thermostat we use when we’re gone for more than a day.  We do not have a furnace.  Last year we went through 2 chords of wood and about 70 gallons of propane.  I had quite an argument with our propane dealer.  I wanted a 500 gallon propane tank and he insisted that I needed a 1500 gallon tank for the size house I have and the weather conditions up here.  Since the area can be very difficult to get in and out of in the winter, he told me he would refuse delivery when I run out of propane in February.  I told him not to wait for my call.

27

we_are-toast,
Thanks for the excellent information.  I also live in a snowy, cold weather area and have forest fire concerns as well so your information is definitely useful.  After having built the house, is there anything significant you would have done differently?

P.S.  I’m impressed by you not having those particular trade skills and taking on and finishing a project of that magnitude.  You’re an inspiration!

28

There are always things that I think I could improve on.  Some, because I’m curious how a different approach would have worked out, and others simply because my lack of experience caught up with me.

I certainly underestimated the number of thermal solar panels I needed to warm up the large thermal mass I have in the floor.  At some point I’ll probably double the number of panels.  I would also give more thought at mounting the panels prior to putting the metal roof on, and may even consider mounting panels in the roof rather than on the roof.  With the cold wind, I might also consider vacuum tube collectors rather than flat plate collectors.

I would run individual 1/2" hot water lines to hot water outlets rather than using a branch system.

If I didn’t live in a high wind area, I would consider a super insulated, double wall frame construction technique rather than the ICF’s.  There really are so many different methods to massively improve energy efficiency and reduce your carbon based energy usage that people really have the option of choosing what is best for their local conditions, needs, budget, and abilities. 

Rhare has really presented some great information about his approach to his situation in wonderful detail.  He is also very correct in that system size, approaches, and costs can scale.   I might consider his approach as a Cadillac method, and my approach as a Hyundai method.  My 1KW off grid PV system, my small wind generator, and my 100 ft^2 thermal system cost roughly $13,000 before credits and + my time.  I hope others can find some place in between our approaches or maybe an entirely different approach that will meet their personal needs.

29

I was at the Lowesville Seminar also.  I probably saw you there.
I live in Virginia and the panels that we have here are working just fine. We put up 6 kW solar thermal/hot water panels first and then a string of 4kW PV.  We then moved to the micro inverter panels which are more efficient.  We put up 8Kw PV on the garage and then, because we had solar credits for one more kW (what the heck), we put up 4 more panels this month. We do not have batteries. They decrease efficiency, don’t last very long, and are expensive.  The system will allow us to add them on later.

My husband is the “go to guy” for this project, but I can tell you, it doesn’t look very complicated. There are no moving parts and should be no maintenance. I see an extra electrical box on the wall and another water tank in the basement. I also see the meter running backwards all day.  Sweet.

The initial cost of the project was $70,000.  After state and federal rebates the cost was around $30,000. With SREC payments each month and savings on electricity, the payback period should be 5-6 years.

The key to this cost efficiency are the state and federal rebates.  There was a small window for getting the rebates here in Virginia (24 hours on the first go round).  The federal rebates will last until the end of the year. The fed rebates alone will save a third of the cost, which will certainly make the project a lot more affordable.

One other thing I will pass on, if you do this project, shop around for the best contract for the SREC paybacks.  The first solar installer, who we didn’t like, signed us up for a five year contract which gives him a payout (kickback?) of 100.00/mo.  There was so much going on and everything was so new, we didn’t know we could shop around for rates.   The next time around we got a month to month rate at a higher payout.

I hope you find this information helpful. 

30

This is a wonderful and well written description of the details that eluded me when I put in our PV and solar Thermal system with a natural gas generator backup.  The generator  has a cut off switch for power outages but I put it in AFTER the PV system and I am not entirely sure that in case of power outage, our system will be able to generate power from the PV in addition to the generator.  Having a mini grid Island is just what I needed to know.
My next project is to build an off the grid capable apartment in a new barn on my newly purchased small farm.  I have already forwarded your article to my architect! 

Thanks for taking the time to share your valuable experience with us.

Mark

31

Point of correction…the federal solar tax credits run thru 2016 as of right now.

The credits that end this tax year are for improvements like high effeciency appliances, windows, etc.

32

The latest Senate tax cut bill extends those credits, with some changes.  Most observers think a tax

cut bill will pass (after some modifications by the House of Representatives).

 

33

This is all well and good if you have Thousands of Dollars and a Large House in the Desert.
How about if you are poor and have a small apartment with 3 narrow windows and want Photo Voltaics to power a 625 watt machine that cycles to 100 watts several times a night? A Kill-A-Watt is coming next.

I have already Cut our Energy Usage to the bone. If I could knock $20 off our electric bill in Hawai’i by powering this Peritoneal Dialysis Machine with solar panels it would make my day. I don’t care if I only get 6 days a month of relief from HECO with this machine.

I have room for 9 panels @ 20 watts each with a full 6 hours of sun almost every day. Wish it could be more.
I have a Zantrex Sine 2000 inverter.
Charge controller is on the way.

Battery size and number is the problem. I don’t know what size battery(s) to get.

34

We were fortunate to have a great situation for solar and the funds to do so, however, it sounds like you have in mind what is feasible with your housing and financial situation.  Just being aware of the three E’s and thinking about what you can do puts you way ahead of most people.

Just be aware that the full sun does not mean full output.  You only get peak output when the panels are perfectly perpendicular to the suns rays.  So on a fully sunny day you will get a bell curve with the peak output sometime around noon.  You also take hits for days your panels are not at the exact right angle.

You should play with PV Watts, the link is in the article.  It will show you your expected output when you put in the angles of your intended mounting.  If you use the default de-rate factor you’ll probably be okay.

You won’t be able to size your battery until you know your expected output/draw.  This last year at CES, panasonic had a display of a modular lithium ion battery pack system for solar.  Not sure if it’s available yet, but it might be worth checking into.  You might also want to check into one of the pre-built solar backup kits.  I know people discussed them in the forums, so a few seachs might be useful.

 Good luck, and I would encourage you to post your solution since you are not alone.

 

35

Very nice and thorough explanation. We have installed double axis tracking system at our place and it has proved very cost effective for us.

36

Can you share some details of your system?I've got a GS8048 inverter with 18 sharp 240 w panels with battery backup,  and on another building some enphase 215's selling back to the grid.  We have a total of 10kw of array. Almost self sustaining at this point. However the summer months coming up with AC are high usage for us in Texas. If we can conserve through those months, we might consider going totally off the grid.