Ways to use solar water heating in a home

I love to talk and write about solar technologies.  My goal has always been to encourage all things solar because I think awareness of one type of solar system will benefit all the others.  Solar PV is the darling of the clean energy world--for good reason.  It produces versatile energy in a clean, quiet, safe, and predictable way.  The major downsides are its current cost and efficiency.  While these problems will be overcome with time, solar water heating is ready today.  It's still fun for me to see a home making 130 degree F water just from the sun on a cold March afternoon in Chicago. While my primary focus is on solar domestic water heating, I wanted to expand on some other ways a solar water heating systems could be used in a normal US home.

Solar Domestic Water Heating
The most simple way to harness the power of the sun in a home (after daylighting and applying passive solar design principles) is to heat up domestic (drinking) water with a solar water heating system.  This technology is well-established and easily adaptable to almost any home or building with a hot water demand.  Solar domestic water heaters are sized to reduce the water heating bill of any home in the US by 60-80%.  A typical home would need about 2 solar panels (50 - 80 sq. ft.) and about an 80 gallon storage tank.  Any solar system of this type will have some sort of back up water heating component to ensure that the residents have a steady supply of hot water despite the solar conditions of a particular day.

Solar Space Heating
If a homeowner is looking to squeeze a little more heat out of a solar water heating system and try to contribute some of this free energy to heating the home, there are a couple of ways to accomplish this. Not to be confused with a solar air heater, I'm still talking about an automatic system that heats up a liquid for use in the house.

Option 1:
Homes with an existing forced air furnace could install a solar water heating system sized to heat nearly 100% of the domestic water heating demand plus make a contribution to space heating (~25% or so).  A system of this sort would have about 5-6 solar collectors (150 - 240 sq. ft.) and about 200 gallons of storage tank volume.  This solar system would operate just as in the diagram above but have a second heat exchanger for transmitting solar heat into the return of the forced air furnace.  The second solar heat exchanger would pre-heat the air returning to the furnace so that it has less of a temperature rise to meet the desired room temperature.

Water-to-Air heat exchanger that would go in the air return side of a forced air furnace

Option 2:
Solar water heating systems could also deliver space heat through the use of a fan convector. A comparably sized system to #1 but without integrating the space heating delivery system to the furnace.  The homeowner could install a system which would automatically divert solar heated fluid through a fan convector(s) strategically placed in the home.  In this scenario, heat from the fan convector would warm the space as it becomes available from the solar system.  This contribution would help keep the thermostat from activating the primary space heating system as often.  A good application for this option might be for a vacation home that needs to be kept warm enough to prevent the pipes from freezing when not being occupied.

Myson fan convector unit on the left. Probably VELUX roof windows above.

Option 3:
Some homes have a hydronic heating system where medium temperature (140 degrees F) water circulates between a water heating unit and various zones throughout a house.  This heating system lends itself to a nice merger with a solar water heater.  As the hydronic fluid returns from a zone in the house depleted of heat, a heat exchanger from the solar storage tank could add heat to the fluid before it reaches the traditional heater.  This is one of the most efficient ways to deliver heat from a solar heated fluid to a living space.  These solar systems could be sized to be rather large (8-10+ collectors) depending on the space heating goals the home may have.

Tubes under the floor deliver heat to the room in a hydronic heating system

For any of these options, this style of heating system isn't usually the best primary space heater for a home since the winter months (when you want heat) typically correlate to shorter days and thus less solar energy to be harvested. Like with a solar domestic water heater, however, a solar space heating system will reduce the number of BTUs the traditional heater will have to deliver to the house even during the winter months.

Solar High Mass Systems
In this variety of space heating using solar energy, a solar water heating system heats up a large mass (many, many tons) of sand under a home which then slowly releases the heat over the winter months.  Owners of these systems begin to direct the solar heat to the sand mass which extracts the heat through a matrix of tubes embedded in the sand.  Many homes in cold climates are accomplishing 75%+ of their space heating needs through this style of solar water heating system.  Not all that complicated or that expensive, Solar High Mass systems will require a bit more homeowner involvement to make them work effectively with their lifestyle.  This also would need to be designed into a new home from the start since so much sand or other high mass material would need to be under the living space.  The Artha Sustainable Living Center is a great resource for more information on these systems.

Solar Assisted Ground Source Heat Pumps
A ground source heat pump (GSHP), aka geothermal, is a device that heats and cools a building by moving heat to and from the living space to a series of pipes in the ground.  Additionally, a GSHP can contribute to the domestic water heating needs of a home as well.  These systems function in a very similar way that a kitchen refrigerator does except the ground is the heat sink in the cooling cycle versus ambient air as with the refrigerator.

Imagine an array of 3-5 solar collectors on the south facing roof to integrate with the GSHP

A rather new implementation of a GSHP adds an array of solar water heating panels to the mix.  This Solar Assisted GSHP offers a few advantages over a standard GSHP:

1. The solar collectors can add heat to the ground all summer to allow the GSHP to be more effective at space heating in the winter.
2. Solar panels can pre-heat domestic water in the summer so that the heat pump may not need to function at all to provide domestic hot water when the weather is temperate.
3. Added heat can come from the solar collectors in the winter to augment the space heating cycle.
4. During the spring and fall, the heating load may be low enough that the solar collectors could provide enough space heat so that the heat pump would not need to operate.

GSHPs slowly deplete the ground heat immediately surrounding the bore wells over the life of the system.  For this reason, many green building codes don't classify this technology as "sustainable" or "renewable."  Coupling a solar array to the GSHP is a way to make this excellent technology truly sustainable.

The solution to our energy problems rises in the east every morning.

Idealism doesn't drive sustainable energy development

Northern Iowa Wind Farm - (Going Green In Orange)

A recent article on Renewable Energy World asks the question how did the US grow an energy consciousness.  I can't say that I agree with the implicit assumption the title makes.  I don't think most Americans really think about energy all that much or how important our current existence is on inexpensive, readily available, easily stored energy.  The United States is blessed (or cursed) with abundant natural resources.  This has clouded our collective long term thinking with respect to energy.  We are able to look at availability of energy on a very short term basis because we've had such a consistent supply of all forms of it for so long.  When was the last time anyone pulled into a gas station and found the filling tanks were empty?  How often do blackouts occur on the power grid? When either of these disruptions happen, big challenges ensue but fortunately they haven't occurred that often.  We get the power we want, when we want it, and it doesn't really cost us that much.

Compare this to energy situation of other countries around the world.  Island nations typically have very limited energy options. Their geographic separation from adjacent countries forces them to generate electricity locally and import petroleum via tanker ship--very costly and risky for their national security.  Japan, the world #2 for installed solar, has also resorted to massive reliance on nuclear which is now showing it's flaws in the most catastrophic way possible.  Faced with limited options, people take risks that they otherwise may not have taken.

Island of renewable energy (Michaelis Energy Island)

Germany is another story as well.  As the global leader in renewable energy development with 17% of its electric power capacity coming from renewables, outsiders may think that the Germans have a particularly strong commitment to clean energy.  While environmental reasons are now one of the arguments that Germans make for continuing their current energy policy, national security issues regarding supply of natural gas were the real spark for their dramatic shift towards wind and solar.  Since the fall of the Soviet Union, Russian natural gas companies have periodically played games with the supply of natural gas flowing to western Europe.  The spark that woke up the German populace was a disruption of gas during the peak heating season over the winter of 1992-93.  Cold homes in the winter are a strong motivating force for spending more on local energy.

The main message that Americans have heard regarding renewable energy is that it's good for the environment.  This is an idealistic message that has been both polarizing and lacking in teeth to drive tangible action by even those who believe the message.  Many people immediately think Quixotic farce when they hear anything about solar or wind development--overly idealistic and impractical.  Focusing on the environmental component to renewable energy makes this a political discussion where there are perceived good guys and bad guys.  We also get a lot less personal satisfaction from an effort to conserve energy while a neighbor continues to be profligate with his consumption and waste.  Our environmental savings are easily erased by people not of the same mindset.  None of this serves the purpose of a steady state energy system where we all have access to reasonably priced energy without the negative externalities of fossil fuels.

My read on the US energy situation is that we have about 10 years or so to make some dramatic changes in our mix of energy options to avoid disruption issues that other countries have already had.  10 years is a long time in the sense that we could (and probably will) chose to continue procrastinating on making the spending decisions that we need to make.  10 years is a short time in the sense that the capital improvements we need to make could take that much time or longer to actually complete.

The RE World article I reference above makes the case that governmental policy has been the most effective change mechanism in the US.  Maybe so but our current energy mix has very little renewable energy in it other than hydroelectric.  I honestly can't tell what the spark will be to awaken the sleeping giant once again and unite our efforts behind a common cause.  Hopefully, it will be something much less dramatic than Pearl Harbor was.

The worst kind of wake up call

- Let's use our brains people and get ahead of these very foreseeable future energy challenges.

Seducing your solar customer

Great link for more tips from Don Draper on how to woo women, I mean solar customers

As I prepare to head up to Custer, WI this weekend for the MREA Energy Fair, I started thinking of a different approaches to solar sales and marketing.  Many of the people involved with solar energy are so enthusiastic about it that it lead me to the conclusion that green energy fairs are a lot like a singles bar for environmentalists. It's the place renewable energy enthusiasts go to be seen and meet new sustainable products.  So continuing down this line of thought, I realized that the art of meeting members of the opposite sex is merely a very personal sales process.  Just as there are no "10 easy steps" to meeting someone interesting, there is no checklist that will guarantee that you to close more solar business.  That being said, there are some effective strategies to consider, re-consider, apply, and refine in both venues before you set off to woo.  Take some time to think about your "game" and put some of these strategies into action. 

Pay attention.  Focus all your attention on your customer to learn their true solar motivations.  Look at them in the eyes.  Smile at them.  Be enthusiastic about their enthusiasm.

Warm them up.  Be friendly and make it fun for your customer to work with you.  Suggest things to them--don't tell or push them.

Let them talk.  Dominating the conversation is a big turnoff for almost everyone.  Probing questions that give them room to talk are key.  Talk too much and you'll come off as a pushy salesperson.

Take a little care of yourself.  You need to take a shower but the point here is to have a consistent message and corporate appearance that reflects your commitment to providing a professional product.  Bad business cards, logos, company names, and inconsistent solar messaging are the equivalent of long nose hairs or bad breath to a solar business.  Don't Jersey Shore your corporate image though as the sustainable energy community is about doing more with less.  Simple yet consistent is the way to go.

VELUX solar systems only need a 3-person crew to install although it might take all 7 of the Jersey Shore.

Be persistent.  Don't let a rejection get you down.  No matter how good your game might be, not all people are going to click with each other.  The key is to stay in the fight and keep working the crowd.  Have the confidence that renewable energy is the key to a stable future and that there are other like-minded people who you will click with just around the corner.

Don't be too serious.  Despite the many negatives surrounding our current energy situation, don't dwell on the gloom & doom.  Seduction is about making people feel better about themselves.  Turn negatives into positives and draw solar customers to you.  Lighten things up with a natural humor.

Play hard to get.  Solar isn't for everyone.  A subtle cockiness about the exclusivity of joining the solar club will pique interest.  Even though solar is expensive for many, it's not for all.  Those are the people we want to find and they typically don't make buying decisions solely on price.

Time to perform once the deal is closed.  Meeting new people is hard but once they say yes, you aren't home free yet.  You have to remember that the way your installation goes will be a huge factor in repeat business to that customer's peer group.  Neighbors will ask about your customer's system and will be curious about the installation company.  You'd be surprised how many new solar people drag their friends and family to their basements to show off their solar heat or electricity so dress up the balance of system components to impress.  Satisfied customers are your biggest marketing ally.

The solar water heating leader of western Iowa

Solar heated water--on the go!

I met Mike Howard of Iron Eagle Technologies about a year ago when he expressed interest in the VELUX solar water heating system.  Mike lives in a small town in the western part of Iowa called Elk Horn and has an uncanny passion for renewable energy.  While not normally the first place I'd rush off to for a sales call, his efforts on the solar PV and electric vehicle fronts captured the attention of CNN and SEIA for their national reporting so I thought to check him out.  My job is to find the right sort of installation partners to help us grow our solar business and Iron Eagle appeared to be a great fit.

Elk Horn happens to have a thriving Danish cultural heritage attraction called the Danish Villages.  Combining his passion for renewable energy, Mike saw an immediate connection with working with VELUX for solar water heating since our parent company is based in Denmark.  Iron Eagle became a VELUX solar 5-star installation partner last summer and immediately began installing solar water heaters throughout the town.  We installed a 4 panel system on the Elk Horn public school for preheating the water going to the cafeteria.  Later we put a smaller 2 panel system on a home in town.  Mike has also installed 8 panels on the roof of his new Norseman Brewery building--a Danish beer brewed with the help of Danish solar panels!  VELUX couldn't have asked for a better solar installation partner.

Just last week, Mike finished a terrific mobile display of a fully functional solar water heating system.  On the roof of the shed, he mounted 2 VELUX solar collectors in a roof-integrated configuration.  On the side of the she, he had a sink and shower installed.  In addition to using this for general promotional efforts, Mike wanted to provide solar heated water for the bike racers of RAGBRAI coming up on July 25th.  He plans to have ice cream, root beer, and samples of his new Norseman Brewing Company beer for the riders in addition to his solar heated water.  He'll be pulling this display to events with his newly wrapped van that sports graphics of the solar PV and water heating products he installs.

Solar projects for Iron Eagle Technologies in Elk Horn, IA

Solar technologies work and are ready for mass market adoption.  The efforts of people like Mike Howard are just the sort of catalyst that we need to make this a reality.

Rebuild with Solar

Natural disasters are dominating the headlines these days; Mississippi flooding and mega tornadoes have destroyed entire cities across the southeast and in Missouri.  As communities start the clean up process and begin to rebuild, we ought to encourage them to implement better building concepts and materials.  Insurance companies may only pay replacement costs but community leaders could team with local lenders to finance solar systems under established PACE regulations.  Solar technologies are ready today and the only barrier for their adoption is upfront cost.  Considering solar at this stage of the redesign process is the time to make it work most cost effectively and allows for creative ways to mitigate the upfront cost.  We will all be better off for it.

The inevitability of solar

It probably wouldn't be too surprising to learn that I really like solar technology.  Passive solar design, solar air heating, solar cooling, daylighting a space, solar water heating, and PV are all fascinating to me.  I even count biofuels as "solar" too as we're using sunlight to grow plants specifically designed for liquid, transportable fuel.  The energy transition that we're in now feels to me how I think people in the 50's were thinking about space exploration.  Those were hopeful times where technology was magical to the common man and promised positive changes in the future.  Solar today is very much like that; almost everyone sees the promise of it even if they have reservations about its practicality.  My argument though is that solar is also, in all its forms, truly the only sound energy option for the next 25 years or more.  I don't claim that solar will be the only energy technology we'll use, but I see it as the heavy lifter in our energy mix and in that it will provide the bulk of the power we'll need to live the lives we want to live.

I don't say this as an idealist or insider looking to help solar win out over other technologies.  I say it because there are no other candidates on the horizon that will be as scalable and affordable as distributed solar is now and will continue to be for some time.  That is why I'm in the solar business.  I like a clean environment but that didn't motivated me to change careers.  I saw an opportunity to get into a growing solar industry on the ground floor; I see our society as a whole as getting in on the ground floor of solar right now too.  My job is to grow solar water heating in the residential space.  I work to find projects and partners across my region and each system sold is hard fought.  I know that we're not far from a time when solar technology will be on every building, however because we're already seeing the military move in this direction today.  By 2013, solar won't be a novelty anymore but a fundamental building component.

Europe is already there in many areas; what happens when the sleeping giant (US) awakes?

If solar is inevitable, then why even write this post?  Because the journey is just as important as the destination.  Growing a solar base of energy capacity has been sporadic up to this point because we haven't really acknowledged the fundamental instability of our existing energy portfolio.  We're really the only major country without a comprehensive energy policy which is even more damaging because we have the largest impact on world affairs.  Without a consensus behind solar technologies, we'll continue to be distracted by the loser technologies.  We'll fritter away our time & money on dead ends which will make the inevitable shift to solar that much more difficult.

The Losers
Nuclear won't win because we've had over 60 years to figure out a way to handle the waste, danger, and cost of a nuclear plant for electricity generation; we haven't yet and probably won't for at least another 30 years or more.  Coal is plentiful and will probably have a role for some time, but the world will no longer accept externalizing the environmental or societal costs of coal production for much longer.  Agree or disagree, but climate change is an issue that is not going to go away.  Natural gas is plentiful today and at cheap prices but as we continue to load shift transportation and electricity to this fuel, its run as a fossil fuel darling will end too.  If people like T. Boone Pickens can make their case, we'll be burning a lot more natural gas in the coming years; rising prices are sure to follow that move.

I want to be positive towards solar without resorting to throwing other energy sources under the bus (maybe I shouldn't have titled this section The Losers then ;-).  Selling against something is confrontational and tends to put people on the defensive if their world view is being challenged.  Enough can be found on the web bashing fossil fuels, but I wanted to point out up front that the discovery of oil in particular has been one of the most transformative developments in all of human history.  There may have never been a better time to be a human being than right now, and we owe this fact to oil.  It's inevitable that solar technologies will displace oil though and not because oil is dirty or inefficient or imported from hostile countries.  It won't even really be much of a choice to use less oil; it is because oil is becoming too expensive to burn anymore.

2008 numbers; the line is pointing up again today in 2011

Drill baby drill
We're already at a trading range between $90 and $115 per barrel with a global population at or near 7 billion people and the following 3 facts can only lead to even higher prices: 

1. We're going add another billion people in the next 15 years (more mouths to feed).
2. A greater percentage of the world will demand to live with a standard of living as we have in the US (more cars to drive).
3. We are consuming oil as we extract it today and no major reserves exist to make up for rising demand (nothing lasts forever).

Sure we have market players trying to manipulate oil prices.  Sure we limit where we drill new wells based on aesthetic and environmental factors.  The rarely discussed fact is that we haven't found any easily extractable oil reserves in any sort of quantity since the North Sea and now that's almost gone.  We need to be finding reserves on the scale of Saudi Arabia's Ghawar field every couple of years to keep up with the forecasted demand growth from rising global populations but we aren't.  We drill everyday (baby) but we have to acknowledge that the wells are literally running low.  The excellent but sobering documentary The End of Suburbia makes the case for what all this means much better than I can.  My contribution to the debate is to point out that the solar technology we have today can mitigate most if not all these troubles in a very, very short period of time.

Why solar wins
Once we see the scope of the challenge we face, the only conceivable step to take will be a large scale roll out of distributed solar technologies (PV, water heating, space heating, passive design, and daylighting).  It will be the most logical step because it is the step that individuals can actually participate in.  Plumbers can plumb solar water heaters with little or no training.  Carpenters can install skylights today.  Homeowners can connect more PV panels to their homes as their budget allows over time.  New buildings will capture and shed solar heat with no need for new technology--just a rearrangement of building and landscaping materials we use already.  We won't have to wait for anyone in charge or anything else to be invented for a dramatic roll out to occur.  It is really up to us individuals.

Roofing crew installing a solar water heating system

I can imagine that this post will have critics; I haven't really tried to make a convincing argument for many of the details I brought up.  I just wanted to lay out the way I see things though, and I get the feeling that many others are of a similar mind.  Change in life is inevitable and oftentimes difficult.  The sooner that you recognize the change, the better you can prepare, and the smoother the transition will be.  I'll continue to sell solar systems everyday because I enjoy the product, the challenge and the people in the industry.  I know that solar won't be novel for long though and that in many ways, I'm working my self out of a job.  I think that I'll be able to handle that change just fine when the time comes though. 

Reducing water heating costs in multifamily buildings

Solar water heating is a very simple concept; the sun's rays heat water, the heated water is stored in a tank, and then it's used whenever someone wants it.  In previous a post, I made the case that solar works effectively anywhere in the US.  Just because something is possible, it doesn't mean that it's practical however (Nissan Leaf?).  The purpose of this post is to highlight a particular application for solar water heating that can be very rewarding both environmentally and financially.

Here in Chicago, we find many 3-4 story residential buildings that get divided into as many as 12 units.  Some of these buildings are owned as condos with separate unit owners and some have a single owner managing the units as apartments.  In either case, domestic water heating in this style of building can either be done with a central boiler (very common) or with individual water heaters for each unit (less common).  Plumbing a solar water heater as a retrofit to a multifamily building with individual water heaters is probably a less ideal application so I'll highlight two ways to work with a central boiler.

The Chicago Graystone--a typical residential building in the city

Case 1: Condo
In a condominium, each unit is individually owned.  The unit owner pays a mortgage on their unit as well as an association assessment to handle shared expenses (snow removal, common area heating/cooling/lighting, landscaping, roof repair, etc).  In the case of a condo building with a central water heater, domestic water heating is a shared expense.  In this case, a modestly sized solar water heater could be plumbed in-line before the existing water heater to pre-heat all incoming cold water into that tank.  A 6-unit building could see 60-80% water heating cost reduction with just a 3-4 panel system.  The cost of this system would be shared by the unit owners.  The unit owners would then calculate their ownership percentage of the new solar system installation costs to claim the 30% federal tax credit as well as any state or local incentives that might apply.  As a rule of thumb, 1 solar collector for every 2 units should meet federal tax incentive requirements for system productivity.  While organizing a condo association around a capital improvement project like this may be akin to herding cats, implementation of a solar water heater could be very simple to do with a solid return on investment for the association.

Cat Herding--much like many condo meetings I've been to

Case 2: Apartment Building
Many landlords of buildings with central boilers for water heating provide their tenants with hot water as part of the monthly rent.  This scenario may be one of the most attractive applications for a solar water heating system.  Like in a condo building with a central boiler, a solar water heater would pre-heat water flowing into an existing water heater.  The benefits to the landlord are very attractive.  Not only will he or she reduce their monthly costs on water heating bills, but the solar system will bring them a 30% federal tax credit, accelerated depreciation benefit, any state/local incentives, and position the apartment as one that is more attractive to younger tenants than comparable other buildings without solar.  On top of all that, the building will actually have more hot water to draw on so the building manager will get fewer complaints for cold showers.

Solar may have kept him out of hot water with his tenants

 

For further reading, Wisconsin's Focus on Energy program has developed a fact sheet detailing many of the advantages of solar water heating in multifamily applications.  I recommend that you check it out.