Solar Change

[begreen]

I posted an earlier article about this technology being put into manufacture in Germany. Looks like it's starting to happen here. This is a local article. When solar is practical in Seattle, that's news. MSG, in Boulder, you would be in fat city.

http://seattlepi.nwsource.com/opinion/280625_solarcell10.html

 

[BrotherBart]

Well, if I was MSG and sold five to six hundred stoves a year I would be in a conundrum.

 

[MountainStoveGuy]

You would think this would be solar city, with great insolation and the amount of sunny days. Its been a slow start for us, some of the full service shops in town are cranking out systems.
BB, in the stove world, thats not huge volume by any means LOL.

 

[precaud]

Vedy eeentarestink...

 

[the_guad]

Wow, that would be phenomenal. If I could pay $5000 for residential solar, I would buy it today. $20000 puts me off...

 

[elkimmeg]

Energy cost of a home these are averages 60% heating 29% electricity 8% hot water. If this is true then, Solar just for hot water makes little economic sense, Especially when solar does not carry 100% of the load. Way back in the 70's I planned on Solar hot water. But the cost even with rebates and tax credits cost wise there was little incentive. This is not saying it is a bad thing or ecologically responsible but It has to make sense. Now if Solar Hot water could be transered into sharing the home heating load, then things start looking more attractive. Even if hot water consumed 15% of your energy bill one has to crunch numbers Also factor in the colectors and exchangers need in the system and warranty time frame. Time to break even, payback is useless if out of warranty

 

[begreen]

Encourage your state PUDs to have an aggressive buy back program for grid-tied systems. That is where the payback is. The panels run the meter backward while you are not at home. This is money in the bank. With the near 20% efficiency of these panels, they will work on cloudy days. With a significant cost reduction in manufacturing they become very approachable. However, the first mass usage will be a mega-solar power stations.

(broken link removed)

 

[cbrodsky]

Energy cost of a home these are averages 60% heating 29% electricity 8% hot water. If this is true then, Solar just for hot water makes little economic sense, Especially when solar does not carry 100% of the load. Way back in the 70's I planned on Solar hot water. But the cost even with rebates and tax credits cost wise there was little incentive. This is not saying it is a bad thing or ecologically responsible but It has to make sense. Now if Solar Hot water could be transered into sharing the home heating load, then things start looking more attractive. Even if hot water consumed 15% of your energy bill one has to crunch numbers Also factor in the colectors and exchangers need in the system and warranty time frame. Time to break even, payback is useless if out of warranty

We're putting this in now - I looked at the numbers fairly carefully, and I think this is definitely a case where your mileage may vary.

We have a oil fired boiler that we will be able to shut down 8 months/year on average with solar DHW and woodstove for shoulder seasons. My combined standby loss out of the boiler during that period coupled with domestic hot water use was burning 0.85 gallons/day. (based on real use data the past three years during periods when the heat was shut off) At $2.50/gallon, that's a little over $600/year with a family of two. Note we already have front-load washer and high efficiency dishwasher so a family of 4 with old appliances might spend more in this situation. We will also get some modest production during the other 4 months/year, but we have to run the furnace regardless so the standby loss isn't avoided during that period. Net is about $650/year saved - much more than 8% in our situation.

The system we are putting in will run us a bit under $5K installed (w/10 yr complete system installation warranty) after federal and NY state tax rebates, so the payback is quite solid. Simple payback in 6-7 years, 10% ROI over 10 year life, and 18% ROI over anticipated 30-yr life of system with an assumption of 5% annual energy cost inflation. Note those are tax-free returns as well. There are a few other intangible benefits - the solar system will be able to deliver much more than our current system half of the year, thus I can enjoy my jacuzzi tub with much less guilt and plan to do so. Additionally, our furnace is very noisy so I look forward to shutting it down much of the year.

Now if you run this calculation for someone with natural gas fired stand-alone and well insulated water heater, the case is much harder to make - the payback period will be a lot longer.

I also looked at the alternative scenario of using electric hot water. This would still let us shut down the boiler, accomplishing a good chunk of oil savings. However, even with the much higher efficiency and lower standby loss, I still concluded I would come out behind - and I'm also exposing myself to a big unknown in future electricity costs.

From a strictly financial perspective, I'd strongly recommend investigating such systems in 2006-2007 if you have an oil fired boiler that you could otherwise shut down much of the year, you live in a state like NY that has extra incentives on top of the federal, and you don't expect oil to drop back to $1.20-$1.50/gallon again. Beyond that, it's a good thing to encourage for giving the industry scale to drive down costs.

I'd be happy to share more details with anyone interested as we proceed with this project.

-Colin

 

[Sandor]

Colin, excellent post. I would really like to hear how things progress. I know there are several of us on this board that is contemplating solar water heat. Also, some of your observations on functionality during less optimal days. i.e: collector return temperature, tank temperature, etc.

All of my research shows that solar water heating is the most cost effective solar implementation.

I have an electric water heater and by my best estimates, I figure its costing roughly $50 a month, with 3 women in the house.

It looks like there are several systems I can install myself for about $4K. Four thousand bucks in a 5% CD will earn about $200 a year, before taxes. Solar hot water at best will save $600/year, but more likely 3-4 hundred. So, the math works at todays electric rates.

Going to wait until I build a garage on the house to put the 80 gallon solar water tank.

 

[cbrodsky]

Colin, excellent post. I would really like to hear how things progress. I know there are several of us on this board that is contemplating solar water heat. Also, some of your observations on functionality during less optimal days. i.e: collector return temperature, tank temperature, etc.

All of my research shows that solar water heating is the most cost effective solar implementation.

I have an electric water heater and by my best estimates, I figure its costing roughly $50 a month, with 3 women in the house.

It looks like there are several systems I can install myself for about $4K. Four thousand bucks in a 5% CD will earn about $200 a year, before taxes. Solar hot water at best will save $600/year, but more likely 3-4 hundred. So, the math works at todays electric rates.

Going to wait until I build a garage on the house to put the 80 gallon solar water tank.

Sure, I intend to keep people informed of how it works out. We will be installing three panels with a 120 gallon storage tank including electric backup. We will also use a drainback system that will send an antifreeze blend to the roof and drain down in the evening. Originally, I was thinking closed loop with antifreeze, but for a small increase in cost, the drainback designs look to be much easier to maintain and better efficiency ASSUMING you don't use that as a shortcut to avoid antifreeze - that caused a lot of problems for folks with early drainback systems. Bsaically you only fill the panels when you need hot water and the temperature is high enough to merit sending the fluid up there to heat - if these conditions are not met, you don't have to worry about antifreeze degradation from material getting stuck in the roof panels when all your heat needs are met, eliminating need for a wasteful heat dump on very hot summer days. These system have been proven to offer incremental advantages in efficiency, and they don't need to be pumped full with antifreeze to charge them thus making it a simple task to maintain them.

Our roof location is not at all 100% ideal, but we are also keeping appearances in mind for resale considerations down the road. They will be west-southwest facing at about 30 degrees with sun from 9-3 daily with leaves on the trees; expect more exposure in winter. With this setup, the company's projections are hot water production equivalent to about 18 million BTUs yearly. This is something you'd have to compare against your alternative hot water source after accounting for losses in efficiency (esp. oil and moderately with gas fired; not so much w/electric) as well as standby losses, which can be dramatic on a boiler-based system. You could easily required 36 million BTUs of input to your oil furnace to get 18 million BTUs into your hot water when accounting for these factors. Obviously you would expect more production in a southern climate, or a 100% exposed installation, but then again, southern states may not give you an extra 25% state rebate...

By the way, the cost quoted is with all installation performed by a contractor including renting a lift for the solar panels to get up to the roof, running electric for the backup element, etc... I think that is the fairest way to price when comparing return on investment, since it doesn't take me much effort to open a CD as the alternative for my $4900 investment If you already have some infrastructure like an existing electrical tank, or even a gas tank that you can tap into, that would save you a lot of money.

If you were to do the work youself, I think after tax rebates, it can be done for $3-4K - maybe even less in VA since you may not need three panels. But then you have to factor in the value of your time to make an apples-to-apples comparison. In reality, I enjoy this and plan to do some parts of the work myself to get the cost closer to $4000. But I don't want to mislead the actual turnkey cost.

By the way, you mention an important point on taxes - if you earn 5% in that CD, after tax, you may only see 3-4% depending on your circumstances. On the other hand, when you save money on energy expenses, that is after tax money. So you are looking at a tax-free ROI when you displace energy expenses. That is an important factor - paying a $100 oil bill requires that you earn more like $130-$150 at work.

In the end, the most important parameters that influence the financial side of the decision are:

Installed Cost - higher in northern states
Federal + State Rebates - higher in blue states
Energy price for your alternative today and projected inflation rate - big guess
Efficiency and standby losses of your existing hot water supply system - can be accurately determined with good records

-Colin

 

[got wood?]

I was looking into a grid-tied PV system a while ago and a friend mentioned that more energy is used to manufacture a PV panel than is ever generated from that same panel over its life. While I can understand it consumes a great deal of power to produce the various styles of PV panels today, I have a hard time imagining these PV systems can't produce substantially more power over their life that exceeds manufacturing demands. Does anyone know for sure of have any insight into this? I'd really love to get a PV system but I think I may hold out until a more `green' administration puts even more tax and/or install incentives in place.

 

[begreen]

Good point. Basically, almost all human industrial activity is energy intensive if one looks at the full life cycle. Coal is particularly so if one looks at the total cost to health and environment and yet 50% of our power comes from coal. This is why conservation is a really good first step. The statement is for a silicon based system and is somewhat deceptive. What if the energy used for manufacture came from hydropower? A good solar panel can have a 25+ yr. lifespan so when amortized over it's life, the panel is a net power gain. But we can do much better.

New processes are already using way less energy to manufacture and should make the return on energy invested much quicker. The CIGS cell mentioned above is an example. Nanosolar is promising as well. Thin-film uses little or perhaps no silicon. I think we'll be seeing a lot of development in this area in the next few years. I'm excited, can't happen too soon for me!

http://www.redherring.com/Article.a...o+Go+Large&sector=Industries&subsector=Energy

 

[got wood?]

ahhh, but what about a tankless heater and a modest solar setup in every home...that would help that huge surge and to decentralize our aging power grid.

So close to going solar...and to boot I've got a nice sized maple that would have to go to help with the afternoon sun on the panels, 2x the benefit!

 

[cbrodsky]

ahhh, but what about a tankless heater and a modest solar setup in every home...that would help that huge surge and to decentralize our aging power grid.

So close to going solar...and to boot I've got a nice sized maple that would have to go to help with the afternoon sun on the panels, 2x the benefit!

Once you have the solar, you'll have such a well insulated storage system that it wouldn't make much sense to bother with a tankless coil. With a large storage tank and electric backup, it'll be incredibly efficient, and you can always put that backup on a timer to only draw power during low periods should your storage tank start running low.

The other thing you'd find is that once you setup a small system, the additional cost to go from a 80 to 120 gallon tank, or two to three panels is fairly small. In either case, the labor cost will be nearly identical and much of the infrastructure will still be the same. For example, in our case sizing two versus three panels, it worked out that about 14% increase in cost added 50% in annual output.

-Colin

 

[begreen]

Can you accomodate a vacuum solar heater on your roof? That seems like the way to go if you can.

 

[cbrodsky]

Can you accomodate a vacuum solar heater on your roof? That seems like the way to go if you can.

I was originally looking at going that route but ended up changing my mind due to a few factors. Our sun ideal is less than ideal, making it hard to recoup the potential claimed cost difference. Also, I have seen that these systems are more prone to frost and snow buildup, thus diminshing some of the benefits claimed. A recent European paper showed no advantage partially due to this issue. I also felt the standard panels have a very solid proven track record - on the other hand, our vendor has found isolated cases of people's tubes getting damaged when trying to clear snow buildup, etc... Finally, we decided we had enough room on the roof to accommodate the larger black panels, and my wife thought those were better looking.

Someone else on this forum (forget who) also had some similar opinions along these lines which also got me thinking twice about it.

-Colin

 

[Rhone]

That was me where, the more I researched evacuated tubes the more I repeatedly found the information they gave misleading or simply their strengths are inferior.

So, NY Soapstone when you springing for it? I'm pretty sure it'll be next year for me! I can't wait.

 

[cbrodsky]

That was me. I analyzed all the points of the evacuated tube vs. flat plate and over and over again found the evacuated tube's major features to be inferior or misleading.

So, NY Soapstone when you springing for it? The way things are looking it'll be next year for me! I can't wait.

Yea, as much as I love the concept, it does seem to have practical limitations. And one of my main motivators, placement flexibility, was eliminated when realizing we have good locations for the larger flat panels.

We've already signed the contract - hoping to have things up within a month - will depend on how fast the parts come in. I will be assisting the installer with the job so it'll be an interesting experience.

-Colin

 

[Rhone]

That is awesome! Three panels, I like that. Most systems are two, you've got a big DHW solar heating system.

I only get Federal Incentives and they expire on 12/31/2007 so, it's next year for me. The system has to be "installed and operational" by the deadline. I plan on getting 6 panels & 3 tanks so I meet the federal tax credit and only use it for DHW. The following year or year after purchase and install radiant floor heating so I can use it to heat my house in Spring & Fall and section it off so 1 tank is DHW only and the other 2 are for radiant floor heating. That's my goal, I wish I had the paperwork signed off for sure!

 

[cbrodsky]

That is awesome! Three panels, I like that. Most systems are two, you've got a big DHW solar heating system.

I only get Federal Incentives and they expire on 12/31/2007 so, it's next year for me. The system has to be "installed and operational" by the deadline. I plan on getting 6 panels & 3 tanks so I meet the federal tax credit and only use it for DHW. The following year or year after purchase and install radiant floor heating so I can use it to heat my house in Spring & Fall and section it off so 1 tank is DHW only and the other 2 are for radiant floor heating. That's my goal, I wish I had the paperwork signed off for sure!

Yea, we were back and forth on this - our site is less than ideal with unrestricted sun only coming through from 10AM to 3PM when leaves are out. That being said, the output peak is so high in summer, this still isn't much of an issue. And in winter, the trees lose their leaves.

My primary goal was making sure we are still producing well into early spring / late fall enough that we can keep our central boiler shut down and rely on wood and solar and use electric backup only in extreme circumstances. Additionally, we have a large jacuzzi tub that I plan to make much more use of in those months where we have excess capacity. For the extra 14% in cost to get 50% more stored output, I thought it was a good way to go. Will also be good from a resale perspective to have a system that can support a substantial family without problems.

I assume you are getting parts only - sounds like those components alone would max out the federal tax credit cap of 30% up to $2K. That much equipment installed would run quite a bit more. But there is technically a loophole that may not yet have closed where the wording leaves you open to claiming the deduction two consecutive years if you find yourself pressured by the cap. Not sure if the IRS clamped down on that or not yet.

-Colin

 

[cbrodsky]

Quick update to this thread... as of 5PM today, we made our first bit of solar hot water with the new system for a couple hours... amazingly, we were running until 7PM which is nearly dark this time of year up here! Of course the solar tank was also at groundwater temperature, so pretty easy to get some gain going to the roof for those couple of hours

Tomorrow is looking like great weather to charge up the 120 gallon tank - many more details to come in a new thread once we get some pictures and experience.

-Colin

 

[Sandor]

Quick update to this thread... as of 5PM today, we made our first bit of solar hot water with the new system for a couple hours... amazingly, we were running until 7PM which is nearly dark this time of year up here! Of course the solar tank was also at groundwater temperature, so pretty easy to get some gain going to the roof for those couple of hours

Tomorrow is looking like great weather to charge up the 120 gallon tank - many more details to come in a new thread once we get some pictures and experience.

-Colin

PLEASE PLEASE PLEASE!

 

[RoosterBoy]

hay guys have you seen (broken link removed) they claim to be shipping 3000w solar panels right now
just thought id share

thanks
Jason

 

[scfa99]

Quick update to this thread... as of 5PM today, we made our first bit of solar hot water with the new system for a couple hours... amazingly, we were running until 7PM which is nearly dark this time of year up here! Of course the solar tank was also at groundwater temperature, so pretty easy to get some gain going to the roof for those couple of hours

Tomorrow is looking like great weather to charge up the 120 gallon tank - many more details to come in a new thread once we get some pictures and experience.

-Colin

NY Soapstone, I did a quick search and couldn't find the new thread for this. any updates? thanks, i'm looking to do a similar setup.

 

[cbrodsky]

Quick update to this thread... as of 5PM today, we made our first bit of solar hot water with the new system for a couple hours... amazingly, we were running until 7PM which is nearly dark this time of year up here! Of course the solar tank was also at groundwater temperature, so pretty easy to get some gain going to the roof for those couple of hours

Tomorrow is looking like great weather to charge up the 120 gallon tank - many more details to come in a new thread once we get some pictures and experience.

-Colin

NY Soapstone, I did a quick search and couldn't find the new thread for this. any updates? thanks, i'm looking to do a similar setup.

Hi -

Yea, I know an update is long overdue... but this time of year we don't have tons of production of interest.

In general, we have just been preheating the groundwater prior to going into the tankless coil - it will likely be March or April before we go to 100% solar. But, some observations that may or may not be of interest...

Through October, it was hard for us to gauge performance because it was just using a differential controller and we had no idea how long it ran or what the tank temperature was. It was warm, but not hot. Since then, we have also taken down a tree that was responsible for significant shading in the mid afternoon - something we knew we had to do anyway because it was rotten, and this was recommended during the site survey. (see other thread for pics That will make a significant improvement as we go into spring as that is peak production time with our orientation.

We finally got the temperature readout installed in early November. During this period, the 120 gallon tank would be about 70 degrees, vs incoming groundwater in the low 50s. At most, the solar system would run 3-4 hours/day - it would shut off quite a bit earlier than in October due to the lower temperatures and poorer sun exposure - we still had the tree blocking some sun as well.

By December, it was getting up to around 58-62 depending on the weather. On a typical day in the 40s with mostly sun, the system runs about 2 hours, and produces about 10,000 BTUs/hr while running. So not a ton of heat this time of year, but it has still let us get away with lower temperatures on the central boiler since the water is coming in a bit warmer than normal.

Estimating for those two months based on hours of operation logged by the controller, we put 750,000 BTU into the water in Nov; 350,000 in Dec. Assuming about 70% efficiency on the oil burner transferring heat into the water, it would have taken about 11.4 gallons of oil to generate the same heat in the boiler.

This is remarkably close to our projections - believe it or not, when I did our payback analysis, I had projected saving 12 gallons total between Nov/Dec, although the way I got to that number was a little different!

Obviously this trend will start reversing again now going into longer days and higher sun angles and we will see things increase substantially going into spring, and the elimination of a tree will make a big difference.

One other thing I should also mention is that our panels are closer to WSW rather than due south and at 30 degree incline. This means that we don't anticipate a lot of winter production, but as the sun comes back up, we will see a substantial increase - I can tell a marked difference between October and December, for example. Our goal is to shut down the boiler altogether for 6-8 months when we don't need backup heat - will not be able to determine that for sure until March or April. That is key to the payback since you eliminate all hot water demand use and standby losses - anything you get in winter is just a nice bonus. Once we shut down the boiler, the combination of saving all standby losses as well as hot water production costs works out to about $75/month at current oil prices. If you really wanted higher winter production, you would want to mount them on a south facing roof at a higher angle. In our case, the location chosen sacrifies a little winter production for the fact that they are nearly impossible to see driving or walking up to the house - something we felt was important for resale someday. And no matter how you orient, the big production/savings comes from the spring-fall period.

If you have any specific questions, I would be glad to answer them - I worked with the installer throughout the job so most all of it I am familiar with.

I also have a spreadsheet that may be useful to illustrate what we looked at as part of the decision process - will try to post it sometime. It is a much harder case to make if you are using a natural gas hot water heater, or have cheap electric rates, for example; a tankless coil system is one of the easiest to make the economic case.

-Colin