Free Talk Titled What is Solar Water Heating

 Complete Resources announces a schedule of free talks titled “What is Solar Water Heating?” The talks will be offered to the general public with the intention of educating people about solar water heating and how they may benefit from it.

 The talks will include a brief history of solar water heating in the United States covering the first solar water heating systems patented in the U.S., the “Climax” and the “Day and Night” solar water heating systems. The components of a solar water heating system will then be discussed with an explanation of the different types of collectors available, and how the collectors are mounted on a roof, and the types of heat exchangers and storage tanks available.

 An explanation of the different types of solar water heating systems will then be discussed including both passive and active systems. It will be explained how these systems function in differing climates and different applications.

 Next the speaker will discuss how a solar water heating system works including solar radiation, how the solar heat gets transferred to the water, the importance of storing the heated water for use, and controlling the system.

 Also included in the talk are things your home needs for a successful solar installation such as exposure to the sun, and adequate space for mounting the collectors. Then a brief overview of the basic installation procedures will be covered. The speaker will also cover tax credits, both state and federal.

 Check the Complete Resources website for an up to date schedule of free talks and other solar water heating training opportunities. The first talk is scheduled for December 15, 2009 at 7 pm at the Athens Clarke County Library.

 Tony Purcell is the speaker for the talks. Tony is the owner of Complete Resources and is a certified solar thermal installer with the North American Board of Certified Energy Practitioners. He is a licensed residential contractor in Georgia, a LEED AP and a member of the US Green Building Council. Tony is a graduate of Georgia Tech with a Bachelor of Mechanical Engineering and a graduate of West Georgia College with a Bachelor of Science in Physics.

Return on Investment for Solar Water Heating

The Department of Energy says that the average household spends from 14% to 25% of its utility cost for heating water. This means if your monthly utility bills total $100, that $14 to $25 is being spent to heat water.

 The Department of Energy also says that a solar water heating system will save between 50% and 80% on the cost of heating water. Using the same totals as above (assuming a $100 monthly utility bill), the monthly savings from installing a solar water heating system will be between $7 and $20.

 Using a simple return on investment calculation and assuming the cost of installing a solar water heating system is $6000, and taking the Federal tax credit of 30%, and the Georgia state tax credit of 35% into account, the installed cost of the system (after tax credits) is $2100. Then taking the monthly savings of (between) $7 and $20 and dividing it into the $2100 cost, the return on investment is between 25 years and 8.75 years.

 Using some statistical data, for a more specific calculation, from the Department of Energy- Energy Information Administration 2005 survey, table WH6 average annual consumption of fuel type used (physical units per household) for water heating in the south is 2763 KWH. That is 230.25 KWH per month on average. If we assume an average electric cost of $0.10 per KWH, the average household monthly cost for heating water in the south is $23.25. Using this number in our return on investment with the same assumption that a solar water heating system will save between 50% and 80% on the cost of heating water, the monthly savings are between $11.51 and $18.60. Dividing this savings into the cost (after tax credits) of the average installed system, of $2100, the simple return is between 15.2 years and 9.4 years.

 When other factors are taken into consideration such as inflation, utility cost increases, and increase in property value from installing the solar system, etc. the real return on investment drops down in the range of 6 to 8 years. Considering the expected life of the equipment is in the 12 to 15 year range, the investment makes even more sense because a positive cash flow is soon recognized.

Complete Resources is a solar contractor and green builder in Athens GA. Complete Resources also offers a training class for teaching installation of solar water heating systems using the Power Partners Solar water heating system. The instructor for the class, Tony Purcell is a North American Board of Certified Energy Practitioners Certified Solar Thermal Installer.

Free Energy and Tax Credits!- Why Not?

There’s still time to take advantage of the tax credits for solar installations before the end of the year. In Georgia, you can get 65% of the cost of solar system paid for in tax credits . To take the credit for 2009, the system has to be installed in 2009. But don’t worry, the credits are in effect for a few more years, so if you don’t want to do it this year you can do it in 2010.

For a solar water heating system, you get 35%,  up to $2500 in Georgia state tax credits, and no maximum for federal credits. For a photovoltaic system the maximum state tax credit is $10,500, and there is no maximum on the federal credit. The credits cover component cost and installation cost.  Here is how it works.

To claim the state tax credit, you install the system and then fill out the tax credit pre-approval form which can be found on the GEFA website (Georgia Environmental Facilities Authority). Don’t be fooled by the name “pre-approval”. You don’t get approval before you install the system. You have to install the system before you can get pre-approved for the credit. This is because there is only so much money allocated each year, and because the tax credits aren’t given until the end of the year when you file your tax return, the money is allocated to those who apply first. Once all the money has been allocated for that year, they will stop pre-approving applications for that year. Don’t worry; there is still plenty of money remaining for 2009. For the Federal credit you simply fill out IRS form 5695 and file it with your return. More information on the tax credits can be found on the DSIRE website (Database of State Incentives for Renewables and Efficiency).

Complete Resources is a solar contractor and green builder in Athens GA. Complete Resources also offers a training class for teaching installation of solar water heating systems using the Power Partners Solar water heating system. The instructor for the class, Tony Purcell is a North American Board of Certified Energy Practitioners Certified Solar Thermal Installer.

What a Home Inspector Should Know About a Solar Water Heating System

All manufactured solar collectors come with a mounting system which will typically consist of some sort of rail that is anchored to the roof structure. The most common method of anchoring is with a lag screw through the mounting rail and into the rafter. Some installers will use a “J” bolt hooked to a rafter. Another method involves a long threaded rod that is bolted to a block of wood that spans at least 2 of the rafters in the attic. The key is to look for a substantial anchoring method. A lag screw in the roof decking is not considered to be substantial. If the area is not along the coast or in the mountains, where the sustained winds do not generally exceed 30-35 mph, some manufacturers allow the collector to be anchored to the roof decking without being in the rafters. If this is the case, an expansion type anchor such as a butterfly, or hollow wall anchor should be used.

General practice is to use a roof caulk to seal any roof penetrations. Every bolt should have been pre-drilled and the hole filled with caulk before the bolt is installed. The bolt head should be covered with sealant as should the mounting rail where the bolt passes through. A good quality roofing caulk should be used. A roofing caulk will remain flexible after it cures, whereas an acrylic or latex caulk will harden and crack. Silicone should not be used because it does not have good adhesive properties. Where piping penetrates the roof, a roof flashing boot should be installed. Some system manufacturers supply a special flashing boot with the collector whereas others recommend using a standard plumbing roof boot. The boot should seat on the roof so as to form a positive seal, and not allow water to pool. The boot itself should not come in direct contact with the pipe unless it is rated for high temperature applications (200 + deg. F). Wiring penetrations should have their own flashing/sealant. Wires should not come in direct contact with the pipe because the high temperatures may melt the wire jacket/insulation.

The piping run should be as short as reasonably possible. Longer pipe runs mean more heat loss in the pipe. Any horizontal runs of pipe should be supported every 6 ft. minimum. The supports should be of a material compatible with the pipe material. Most solar systems, unless they are low temperature, will use copper pipe simply because the temperatures get high enough to melt or soften any plastic pipe, even CPVC. Since the pipe will be insulated, a support around the insulation will be most common, in which case it should not come in contact with the pipe. The issue with non compatible materials is the same as with plumbing pipe in that galvanic corrosion can occur with dissimilar materials.

All of the piping between the collectors and the heat exchanger and storage tank should be insulated. Pipe insulation should be a closed cell rubber foam type such as Rubatex, Armaflex, or Armacell with no less than a ½” wall thickness. The thicker the insulation, the better insulating property it will have. There should be no openings, holes or gaps in the insulation. All seams and joints should be taped. Any insulation that is exposed to sunlight should be UV protected with an aluminum tape, paint, or an insulation jacket. Insulation that is not UV protected begins to crumble after relatively short exposure times and will quickly become non-effective.

Most manufacturer’s use a heat exchanger that is integrated with the storage tank, either inside the tank in direct contact with the water, or wrapped around the outside of the tank (but inside the jacket of the water heater.) Typically there will be a label on the tank identifying the type of heat exchanger. If it an immersed heat exchanger, it is most likely a single wall design, meaning there is only one layer of material between the heat exchange fluid and the water inside the tank. If the heat exchanger were to rupture, there could potentially be a contamination of the household and municipal water supply. When a single wall heat exchanger is used in a closed loop pressurized system, common practice is to set the operating pressure of the heat exchange loop to be less than that of the water system. With this done, if the heat exchanger were to rupture, the higher pressure of the water system will not allow the heat exchange fluid to enter the water system. With the wrap around heat exchanger, contamination of the water supply is highly unlikely.

Other manufacturers may utilize an external heat exchanger. Common external heat exchangers are the plate type and some variation of a tube in tube system. In either case they can be identified by the piping coming in to them. One side of the heat exchanger should have the piping from the collectors coming into it, and on the other side should be piping from the water storage tank. To get the maximum efficiency from the heat exchanger the heat from the solar collectors should be exchanged with the coolest water from the tank. This means that the water should come from the bottom of the storage tank (since we know from basic thermodynamics that a cooler fluid will fall while a warmer fluid will rise.) In addition to get the maximum efficiency of heat exchange, all components should be well insulated.

The fluid(s) may be actively pumped, or they may passively flow by thermal siphoning. Some manufacturer’s systems will use a combination of active and passive technologies; however, the majority of them are actively pumped. The pumps are typically small (1/25 hp or less) circulating pumps similar to those used on hot water heating systems. The pump should operate smoothly and quietly and be relatively vibration free. The pump may be hot to the touch so be careful touching it (since it is processing a heated fluid) however it should not be more than a few degrees hotter (if any) than the adjoining pipe. Typically the pump is on the return side (cooler side) in the collector loop. If an external heat exchanger is used, there will probably be two pumps. One for the collector loop and one for the water heater circulation loop. They may or may not be the same size.

The pump(s) may be AC (alternating current) or DC (direct current). The AC pump will have a controller which could be as simple as a timer, or a differential controller which senses at least two different temperatures that it uses to determine when to turn on and off. The pump is typically wired to or plugs in to the controller. The temperature sensors are most commonly located at the bottom of the tank (coldest point) and the collector out (hottest point). A temperature difference between these two points of 15 deg. F is enough for efficient heat exchange and is a common set point for turning the pump on. After the pump runs for a while the temperature of the collector will drop and the temperature at the bottom of the tank will increase. When this temperature difference reaches the 3-4 deg. F range the controller signals the pump to turn off. A differential controlled system will go through many on/off cycles on a sunny day.

A DC pump may or may not have a controller. Most DC pump systems are directly coupled (wired) to a PV (photo-voltaic) panel that is mounted with the collectors (same orientation and tilt). When there is sufficient solar exposure for the thermal collectors to provide heat, there is enough solar radiation for the PV panel to generate electricity to power the pump. The PV panel acts as a controller for the system. A DC system may also use a controller such as the one described for the AC system.

The next most important component is the heat exchange fluid. Most areas of the US require a freeze protected system, and most freeze protected systems use propylene glycol as the heat exchange fluid. Propylene glycol is a food grade anti-freeze. The glycol should be checked for ph and concentration. These are the same checks that you will do for the anti-freeze in your car. A 50/50 mixture of glycol and water is typically recommended to prevent freezing. Usually a basic visual inspection will be enough to determine the condition of the glycol. The system should have a drain valve at or near the heat exchanger. The valve should be slowly and carefully opened draining a small amount of the fluid in a cup. A white colored cup is best so the color of the fluid can be evaluated. Glycol that has begun to oxidize will change colors (begin to darken). The original color may be green, yellow, or red. If any discoloration or burnt smell is noticed it is probably time to change the fluid. A ph test paper will confirm this if there is any doubt.

Most manufacturers have their systems certified by an independent organization such as the Solar Rating Certification Center (SRCC) or Florida Solar Energy Center (FSEC). If the system is certifed by these organizations, then a label indicating the certification and rating will be found on the collector body. Both of these organizations require that the system be accompanied by an operations manual which is typically attached to the storage tank. This manual is important for any new homeowner to have so that they understand how to operate and maintain the system in their new home. If the current owner does not have the manual, then the manufacturer of the system should be contacted and a new manual acquired.

Complete Resources is a green building construction company in Athens, GA that specializes in renewable energy products such as solar water heating systems. More information can be found on their website at www.CompleteResources.net

Solar Space Heating with Hydronic Radiant Heat

There’s nothing like getting free hot water with a solar water heating system, except when you use that free hot water to heat your living space. Combining solar water heating with a hydronic radiant heat floor system is a very effective and energy efficient method of space heating.

Hydronic readiant heat is where water is circulated through pipes to deliver heat to the area. Most commonly the pipes are either embedded in the floor itself, either in a concrete slab or a wood floor, or installed in walls. When in a concrete slab, the  high thermal mass of the concrete holds the temperature for a long time slowly releasing it into the living space. The constant temperature with little or no temperature variation makes the heating method extremely comfortable. In addition, the fact that you are in direct contact with a warm surface makes you feel warmer, so you are able to use a lower thermostat setting, thus saving energy.

Solar water heating systems capture the heat from the sun and transfer it to water where it can be used right away or stored for later use. Typically a series of collectors are mounted on a south facing roof plane of the structure. A heat transfer fluid circulates through the collectors taking the solar heat back to a storage tank where the heat is transferred to water. This is the same water that comes out of your faucet, or it can be circulated through a radiant floor system.

One issue with solar space heating is what to do with the heat during the summer. During the winter, most buildings loose heat very quickly. To replace this heat a high capacity heating system is required. Capturing solar heat is done with thermal collectors, so to get more capacity, you need more collectors. When it is cold outside, there is a need for all the heat the collectors can gather, but when it’s not cold out side, the collectors are still gathering heat. If that heat is not used, it continues to build up in the storage tank, and the system will eventually overheat. Some of the heat can be used for hot water to wash dishes, clothes, showers, etc.,  but the majority of the heat during the summer can not be utilized.

To take advantage of solar space heating you have to design a system that will not overheat during the summer. There are different ways to approach this problem. Most of them involve controls that add cost and complicate a system. The one I have had success with is an alternative mounting arrangement for the collectors.

In general, to maximize the potential of a thermal collector for winter time use, it should be mounted on a tilt angle equal to the location’s latitude plus 15 deg. For example, where I live in Georgia, the latitude is approximately 34 deg. This is the angle the sun will be at its highest point in the sky during the winter. So the ideal winter mounting angle for solar collectors in Georgia is 49 deg., which is approximately equivalent to a roof pitch of 12 in 12. For summer use, this is less than ideal, however, the efficiency of a solar collector is only reduced by roughly 10% for a change in angle (from ideal) of up to 30 degrees. So for summer use, the mounting angle equal to latitude will still provide sufficient exposure for heating water.

The alternative mounting method I have used for solar space heating takes advantage of the fact that the efficiency of the collectors is only reduced by 10% for up to a 30 degree offset in mounting angle. Because the sun is so low in the sky during the winter, I mount the collectors at 90 degrees instead of the angle equal to latitude. This allows the collectors to get very good exposure during the winter, and little or no exposure during the summer. If the system is also used for domestic hot water, I will mount enough of the collectors at the angle of latitude to provide sufficient summer exposure while still maximizing the winter exposure.

Roof Mounted Thermal Collectors

Solar Contractor is the owner of Complete Resources Building and Repair in Athens Georgia. Complete Resources is a design build construction company specializing in renewable energy products and applications such as solar space heating. More information is available at www.completeresources.net

Solar – Just Like Your Car?

When most people decide to buy a car, they do not look at the return on investment. They might look at the engine, the sound system, the dash features, storage space, gas mileage, performance, etc. But I don’t think I have ever heard anyone ask what the return on investment is. I’m sure there are those who do, but the majority of us are driven more by our emotions when it comes to purchasing a car. We consider how good the car looks, or how good we look in the car, or what “so-and so” will think when they see me in that car. The image a car gives us is often more important than it’s functionality.

Some of us buy sporty cars, some buy big cars, some buy trucks or SUV’s, or if we have children we might buy a mini van, or a vehicle that has a higher safety rating. Some more than others buy cars that get good gas mileage, or even a hybrid vehicle, or an electric car. Some people like to buy used cars while others prefer to buy new, and then a few of us lease our vehicles instead of buy them.

Then there is the issue of color. Some of us buy a car to be noticed so we pick a color that is bold, or unique so that it catches attention. Some of us don’t want to be noticed so we pick a color that is neutral or doesn’t stand out. Some are more concerned about the heat during the summer so they go with white, or depending where you live you may pick a dark color so it is warmer during the winter.

We buy cars for different reasons, and with different philosophies, but if we look at why we have a vehicle, it is for one basic purpose – transportation. A car gets us from point A to point B. It serves a function, it is basically a utility.

It’s really not that much different than buying solar. Solar is basically a utility. It heats our water, or provides us electricity to power our lights or run our microwave. It’s function is basically that of a utility. So why are we so concerned with return on investment, or payback when we look at solar? It’s a smart thing to do to consider the return on investment, but it’s not the only reason to invest in solar.

Solar benefits everyone by lowering our need for power to be generated from burning fossil fuels. We reduce the air pollution, conserve our natural resources, and leave a healthier cleaner planet for future generations. So if we look at buying solar like we look at buying a car it might make the decision easier for us. Especially for those who want to be noticed. I promise you if you put solar on your house, people will notice.

Complete Resources is a Green Building Contractor in Athens, GA that specializes in energy efficient building and renewable resources such as solar thermal water heating, solar space heating, and solar electric. www.completresources.net

Why Go Solar?

It’s free energy!

It’s clean energy.

No price fluctuations.

Save money on your energy bills.

There are tax credits.

If you are thinking about installing a solar system in your home or business, you’re doing a good thing. The sun is an tremendous natural resource that we do not take advantage of. There is enough solar energy hitting the earth every day to meet all our energy needs. As solar collector technology improves, this will become more and more evident.

The energy we get from the sun does not pollute our environment.  It’s clean energy. Unlike our current fuel burning power plants, the sun continually bombards us with electromagnetic radiation that is non-polluting.

Because the sun’s energy is free, there are no price fluctuations. There are many factors that effect our current energy costs. With solar energy, the cost is steady.

By installing solar, you eliminate a part, if not all of your need for energy from your current sources. By reducing your energy usage you reduce your energy bills, and save money.

There are incentives out there for installing solar. The federal government has a 30% tax credit, and where I live, Georgia, has a 35% tax credit. That means up to 65% of the cost of a system is covered in tax credits. Some utility providers are now issuing rebates which will be in addition to the tax credits. Walton EMC is offering as much as $400 as a rebate on a system purchased through them.