From Guest Blogger Lillian Connors: Solar Water Heater–an Earth-Friendly Alternative
It doesn’t take a genius to realize that significant savings can be made if we turn to free, renewable sources of energy to heat water, rather than use devices powered by electricity. Needless to say, in order to start utilizing solar power for this purpose you need to make the initial investment, but all calculations show that such an investment pays off relatively quickly. Apart from being most cost-effective, this method is also much more eco-conscious.
Advantages
When you use solar energy, which is both sustainable and clean, you also reduce pollution and carbon footprint, which makes this method very eco-friendly. Also, your electricity bill will be significantly lower and that’s the saving that will soon offset the initial expenditure related to purchase of the necessary equipment. Finally, depending on the climate in your area, a solar water heating system can accommodate the needs of an average family for a whole year, but it might be wise to have a small traditional boiler as a back-up option.
The system
Solar panels, a.k.a. collectors, are installed on your roof. They collect the heat from the sun and use it to warm up the water, which is kept in a hot water cylinder. In case there isn’t enough sunshine or the family’s needs exceed the capacity of the collectors, there’s an option to fit an immersion or boiler heater.
The heating panels, which harvest the heat, can be either flat or in form of evacuated tubes. They can go directly onto the roof tiles or into the roof structure.
It’s worth knowing
The widely accepted myth that solar panels only deliver when there is enough direct sunlight is just that – a myth. There is very little difference, if any, in the way the system operates in cloudy weather. So, find some space on your wall or a flat roof where the panels can be installed.
Speaking about installing equipment, don’t forget you need to fit in a large hot water cylinder somewhere, which is probably a good enough reason to bring in an expert. It’s only with proper installation and maintenance that your system can function smoothly, we learn the guys behind Force Plumbing & Heating.
Maintenance
By the time you get to this stage, you’ll have already made the most significant investments in purchase of equipment and installation. If your budget doesn’t quite cover all the expenses, you might want to consider various bank loans with favourable terms and conditions for installing an eco-friendly heating system, or apply for a government incentive program.
Most solar water heating systems boast a warranty period of between 5 and 10 years, with minimum fuss about maintenance. You’re supposed to receive a maintenance calendar from the professional who installed the system, telling you exactly when and what you’re required to do if you wish to reap the benefits of your investment.
Potential problems
A leak seems to head the list of potential problems and one good thing about it is that you don’t have to see it to know it’s there. Namely, an antifreeze leak gives off a strong, unpleasant smell, making it easy to register. If you can detect a pungent smell, call the installer.
Depending on the system, you’ll need to replace or replenish antifreeze every 3 to 7 years, but that’s best left to professionals. Your job is to contact them when the time comes and follow their advice. Another potential problem is the pump, but they are becoming increasingly cheap and easy to replace, which means it’s not a major issue any more.
So, apart from helping us fight the battle for sustainability and environmental protection, a solar water heating system is also helping you save money. Depending on the area where you live and the system you decide to install, you might save and contribute more or less, but you’ll definitely be making a difference.
Way back in about 1981, I had a solar water heater installed for my condominium in San Diego. It made sense because gas was not available at the unit and heating water with an electric resistance heater is costly. In San Diego, there was no need for antifreeze. Actually, some solar water heater systems are designed so that, by gravity, water will drain down from the panels to avoid freezing thereby eliminating the need for antifreeze and perhaps heat exchangers.
The company that installed the system promptly vanished. The pump failed and because the storage tank had an external pocket to fit the pump, installing a different pump required some plumbing changes. The home owners’ association made me remove the solar panels for roof repair. About that time I sold my unit and the new owner was not interested in the solar water heater and scrapped it. Until then, it worked well except for the pump replacement which would not have been necessary if it had been a high quality pump. I rarely needed the electric heat backup; the solar heat was adequate provided I used some judgment about when I used the washing machine, etc. Even on somewhat cloudy days it worked well.
Here is some advice:
1. Depending on the type of solar heater, it can significantly complicate roof repairs. A solar heater with the tank in the building minimizes that problem because then only the solar panels need to be removed for roof repair.
2. If the system has a pump, examine it closely. Some will last many years; some will not. Be sure that it is a high quality pump made by a respected manufacturer.
3. Check the storage tank. It must be well insulated. For efficiency, it must be able to maintain good thermal stratification. That requires a vertical tank so you will be drawing hot water from the top while cold water is admitted to the bottom and the hot and cold water will not mix. With a horizontal tank, good thermal stratification cannot be maintained and the temperature at the taps will drop more quickly as hot water is used.
4. Check the internal rate of return and go by that instead of payback years. Internal rate of return is by far the best way to evaluate an investment. You can then compare the internal rate of return with the interest you may be paying on loans and how much you could earn with other investments.
5. Unless you will be staying in the house for a long time, try to determine if you will be able to recover you investment if you move. It may be that home buyers will pay no more for a home with a solar water heater.
An experienced installer is very important. Flat plate collectors last 30+ years and the vacuum tubes pictured hopefully will last 10-15 years. Solar is more cost effective when you have more people using hot water in the home. 3 or more people makes economic sense. We have 5 people and it heats 85% of our hot water, and the electric power breaker is off all spring, summer, and fall unless it rains 2 days. AlabamaEnergyDoctors.com
“instant gas water heaters” are not instant, break, need constant descaling, will not heat at low flows, create a cold water sandwich, use fuel (that could be used to make glass or steel), there is a monthly gas meter charge, Consumer Reports said they are not cost effective.
Craig,
There is a hybrid water heater which is a cross between a storage heater and an instant heater. My sister and her husband got one when their storage heater failed.
As I understand it, a hybrid water heater has a very small storage tank; I think that it’s less than one gallon. Because of its small size and good insulation, storage losses from it are very low. The tank is continuously maintained at the desired temperature. The burner and heat exchanger have sufficient capacity to maintain the water temperature as water is used. Also, it could be used with a hot water recirculation pump in which case the pump should be activated only just before hot water will be drawn.
The hybrid water should eliminate the problem of failure to heat at low flows. However, I doubt that the scaling problem would be eliminated by it. Perhaps it is practical only in areas where the water is not heavily mineralized or if used with a water softener.
Perhaps the hybrid water is something that should be considered. But whether a hybrid heater of instant heater would actually be more economical than a storage heater would depend on the pattern of hot water usage. If large amounts of hot water are required, a storage heater may be more economical because it burns gas at a lower rate so less heat is lost through the flu. If very small amounts of hot water are used, than an instant or hybrid heater may be more ecumenical because even though more heat is lost through the flu, storage losses are practically eliminated.
Recommendations on energy saving methods tend to be over-generalized, simplistic, and fail to consider individual circumstances.
2 comments with references:
1. Although a solar thermal water heater suggests a certain elegant and efficient use of energy it may not in every case present the least costly renewable energy solution. There are some who advocate using solar PV panals in combination with a heat pump water heater as cheaper than a solar thermal solution: here is the summary: http://www.treehugger.com/renewable-energy/do-solar-thermal-hot-water-heaters-still-make-sense.html Here is the article update with a link to the original: http://www.greenbuildingadvisor.com/blogs/dept/musings/solar-thermal-really-really-dead
2. There are many more than 5 types of solar thermal hot water systems using terms like “active,” “passive,” “pump-down,” “flat pannel,” “vacuum tube,” and “siphoning…” But this geyser system seems highly innovative while stretching the boundary between active and passive systems. It is simple and eliminates the need for an electrical pump. Here is one of the best articles on it: http://www.homepower.com/articles/solar-water-heating/project-profiles/self-pumped-solar-hot-water-system
Breath,
Your post points up the need to examine individual circumstances carefully. The “one size fits all” approach to energy saving too often fails to produce optimal results.
Another thing that irks me is the blanket statement that all incandescent lights should be replaced with CFLs or LEDs. However, a significant number of lights are in places where they are used only briefly, such as in closets and for stairways. In those places, the lights are on so briefly that the amount of power consumed is trivial. Although constantly turning LEDs off and on will not shorten their lives, that kind of operation will greatly shorten the life of CFLs, a fact which is almost never considered by recommendations.