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The Solar Collectors Heat Storage Supplemental Heat Sources Managing the systems - The Control Unit The Solar Water Heater System

    Frequently Asked Questions

    This concludes the basic tour of the system. The "Next Stop" button below will take you back to the Solar Main Page, or you may continue reading below for answers to some questions often asked.

    Q:Would you consider this project a long term success?

    A:In a word yes. It has saved about half on the expected energy usage for this house over a period of 20 years. It has done so with minimal maintenance requirements. Most of what has been done was in order to simply test various concepts in a real world situation. Some have been integrated where appropriate, others have been dismissed as not worth doing.

    Q:Why do you not generate electricity with your system?

    A:It has not proven to be a cost effective option at this point in time. The high cost of photovoltaic cells compared to the amount of power generated simply does not make it worth while when it is compared to the cost of commercial power. Maybe at some future time when the price of the panels comes down or the cost per kilowatt-hour of commercial power continues to rise this will be an option. But for now, except where commercial power is either not available or extremely unreliable, solar electric just doesn't make economic sense.

    Q:Why the electric furnace instead of a heat pump? I thought they were much more efficient.

    A:They are more efficient. But one need also consider the initial cost. Current units are about 3 times better than resistive heat furnaces. But again the initial cost is about $2500 more than the resistive furnace. Plus in order for the solar system to work in conjunction with a heat pump, modifications would need to be made. These adaptations would also be more involved than those needed to simply replace the sequencers in the electric furnace adding to the cost. But one of the biggest drawbacks is actually a benefit of the solar heat system. Because half of the heat demands are provided by solar, any benefit gained by using a more efficient backup heat system is only half what the average homeowner might expect. This fact alone would double the payback time the heat pump might offer.
    But technology does not stand still. Recent innovations such as geothermal heat pumps and improved performance at lower cost by today's models against what was state of the art a few years ago may at some point in the future make a decision to convert prudent. Quite likely when the existing furnace / Air conditioning fails, or requires expensive repairs I will make the programming changes needed to integrate one of these systems into the existing control system. That is an advantage of computer technology; it can easily be reprogrammed to adapt to changes.

    Q: Why are you using forced air instead of liquid collectors?

    A:At the time the system was installed it was the easiest and most cost effective. Since then I have experimented with liquid collectors on the Water Heater and am actually considering changing to a liquid collector with a liquid to air heat exchanger in the storage unit. The double glazed collector has proven to operate much more efficiently in extreme weather than a single glazed FRP panel.

    However there are good points and bad about both methods. The forced air system is not subject to leaks or freezing. It responds faster to broken cloud conditions since there is not as much mass to heat. Heat transfer is easier since the rest of the system is forced air no heat exchanger is necessary. Also, forced air collectors can be built much less expensively than liquid types. The liquid system has the advantages of needing no large heat ducts, or large collector blowers. Plus, since water is heavier than air the problem of fighting the tendency of hot air to rise in order to force it to the basement storage is not a consideration. Pumps can move more BTU per hour more efficiently than blowers so transfer of heat to storage is better. So in reality it is a trade-off each has its good points and bad.

    Q:Why did you use a custom built controller rather than a PC?

    A:Since this system is one of several which operate my house I wanted to stay with the same general concept. Certainly I could have done it with a regular PC, but since the controller has only one basic duty the versatility of a PC was not an issue. Speed and memory size are also not large so the use of a PC would have been overkill. Besides that the concept was developed in the early 1980s, before PCs were found in every home. Back then even a small computer was expensive, well over $1000. So what I did was develop a small general purpose controller based around the then current 8 bit 8085 processor. I built several of them and incorporated them into various functions in my house. Since then, and to maintain compatibility between systems I have continued to use the same basic controllers. Old, primitive by today's standards, but it still works very well. There would be no advantage to re-inventing the wheel.

    Q:Can you help me design a system for my house?

    A:Unfortunately there is not a lot I can do from here. I don't have your climatic information and other very important bits of information I would need to size a system to your specific needs. All I can do is what is done here, that is give you what has worked for me. It will be up to you to take what is provided, consider your situation, and make adaptations to make it work for you.

    And finally, for a bit of diversion, a question that, as an early user of solar energy, I am asked often. My response may be politically incorrect by some standards, but it deserves consideration in light of the slant being placed on environmental issues today.

    Q:Where do you stand regarding renewable / alternate energy? Isn't that the ultimate goal, to switch from fossil fuels to clean energy?

    A:Not in the foreseeable future. The current trend toward solar electricity has a long way to go. My response here is bound to generate some arguments, especially among those pushing alternative energy. But to digress a bit, let's consider the facts. The sun doesn't shine every day; the wind sometimes doesn't blow, and still we need a reliable source of power. Of course we could lower our expectations; live in darkened, cold (or hot in summertime) houses, turn off our computers and phones, and reduce consumption. We have done that to a point, and that is a good thing. But to go farther will require a significant change in our lifestyle. (Think how your great-grandparents lived!) Most of us are not willing or able to make such a deep reduction. In short we need a consistent, reliable, and cheap source of power.

    Electricity presents a problem. There is no economical way to store it; It must be generated as it is used. And the sun doesn't shine at night. So we will still need conventional power plants unless we are willing to simply shut down our lives at night or on calm days. And to make matters worse some of the highest demands occur when weather conditions reduce available alternative energy sources. Like a winter storm in January with temperatures below zero, or sultry summer days of 90 degrees plus for several days as an example.

    Consider the economics. Suppose for a moment we have become dependent on solar for most of our needs. We only need a small amount of power for those extreme cases. Under those conditions how would a power company justify building a generating station for that one worse case scenario? Could we honestly expect a power company to spend millions to build a power plant for those few days when the sun doesn't shine? Yet that is exactly what some want when they promote alternative energy, they want power plants to sit idle until that one time when they are needed. The only way that could work is for the power generated by that power plant to be so expensive none of us could afford it!

    Some want to subsidize alternate energy sources. But that is not the answer, it simply hides the true cost of alternate energy. That is currently why we are building so many windmills; The true cost of the energy produced is not as cheap as claimed since the cost of building them is not included in the figures. It would be like building a fossil fuel plant and only including the cost of fuel in its final operating costs.

    Another issue is where we live and where the sun shines. The picture below shows the United States seen from space at night. The lights represent us. The more lights, the denser the population, and the higher the demand for power.

    The picture clearly shows that most of us live in the northeast. The southwest is relatively dark, aside from a few population centers. Yet that is exactly where we receive most of our sun. We could generate considerable solar derived energy in the desert southwest, but how do we get it to the northeast? Transporting electricity over long distances involves resistance losses in transmission lines. We minimize these by raising voltages to several hundred thousand volts to go a few hundred miles. But it is thousands of miles from the southwest to the northeast. To cover this distance would require millions of volts. The environmental risks involved in having power lines of this intensity strung across the country would far outweigh any benefits gained. Plus there would still be considerable losses to contend with. And even this doesn't resolve the main problem; The sun still doesn't shine at night!

    Power must be generated and used in the same areas; It is not feasible to move it over too wide of an area. So clearly, while solar installations may provide some power in the southwest, the northeast will require more conventional sources for the majority of its power needs to maintain a reliable power supply. That means coal, nuclear, and hydropower plants will be required.

    Many environmentalists consider hydropower a clean option. The problem with using this source is that its potential is limited. There is only a certain amount of power that can be obtained even if we disregard the impact of placing dams on our rivers. Power is limited by two factors, drop in elevation and water flow. And most suitable sites already are being used. So there is not much room to expand this option.

    The coal, oil and gas, and nuclear options of course can be expanded as needed to meet demands. These will provide a relatively stable source of power regardless of changes in demand since the capacity of the power plant is constant. They provide power day or night, rain or shine. Thus their use must be maintained whether we include solar or wind power or not. It is the only way to ensure power regardless of changes in demand levels.

    Which pushes alternative energy down the list to providing only supplemental portions of our demand. Of course we should include it as a part of the mix, but its importance will be limited when it comes to electricity generation in a free market. Power will continue to be available at lower cost from conventional sources, and the only way to alter that would be to in some way manipulate the market. That is done by either subsidizing the alternative energy markets or driving the cost of conventional power up.

    Which brings us full circle as to why I am using solar as a direct heat source rather than generating electricity on site. In this manner it simply lowers my consumption at a time when others are increasing theirs. When the cold snap hits, my demand for power to provide heat does not increase as fast as my neighbors who are using electricity for their needs. Thus I am helping to stabilize demands on my utility company. This helps keep the load constant on the grid. It keeps my utility costs down while allowing the market to operate freely.

    And for those who question subsidies, consider this. I did get a tax break initially but that program has long since expired. Currently if I wanted to install certain makes or models of electricity generating panels I could get assistance. But only on certain approved systems. And there is no assistance available on a heating system, only electricity systems. The costs of upkeep and maintenance on my system is paid for entirely by myself, as it should be. Maybe it's time to get rid of all the subsidies and interference in the energy field and let the market decide what is the best for our power needs. Coal, nuclear, solar, wind power, or something else. Let things sort themselves out without any outside interference

    Political Rant Over.

    I hope this has answered a few of your questions about my system. If you have any other comments or questions feel free to Contact me using the button and form at the top of this website. I will respond to any general questions you may have.


© J.Brown - AUG - 2015