tag:blogger.com,1999:blog-149778722012-02-02T06:26:21.782-05:00<b>high-performance alternative energy projects and other adventures</b>george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.comBlogger671100tag:blogger.com,1999:blog-14977872.post-41999608763095684312012-02-01T06:35:00.000-05:002012-02-02T06:26:21.790-05:00

Respected Sir, Hope you will be fine. I am a university student in Turkey and doing MS Environmental Engineering. I am interested in designing and application of Concentrator Parabolic Panels as a reactor in waste water treatment. In this technology my basic purpose will be to use UV portion of sun light in degradation of water pollutants. I need your kind guidance in this project. Please guide

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-36726124619353879372012-01-31T07:57:00.000-05:002012-01-31T08:34:38.601-05:00

while searching for ways to build my own solar panels for heating water. I believe I saw that you were using the parabolic system to heat pool water. I'm wondering, could this be used in a residential application? I was hoping to use this for heating our home's water for showers, sinks, etc. How would I determine how many panels I need? We're a family of 5, 7 during the summer. Two bathrooms plus

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-68871476255535527642011-12-14T23:50:00.000-05:002011-12-15T13:07:32.957-05:00

Hello Carlos and thank you for your interest in my book. My answers are below: On 12/14/2011 08:06 PM, carlos e wrote: Hello Mr George,how you doing? I see that you have a great job on this things,congratulations. Thank you. I brougth from you the plans to make my own unit...but I need to get some awnsers first. Did you have some problem with acrilyc durabitity? At first yes but it was

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-63184021551010202722011-12-10T07:20:00.001-05:002011-12-13T10:14:06.760-05:00

Two types of solar thermal collectors are in common use. The parabolic trough concentrator (example mounted on the right side of the solar test jig in the picture), is used in large thermal plants in the desert but is not often home built like the "flat plate" type collector (example at the left) which has avid user/builder groups promoting and advancing it's design and use. Both make great Do

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-3920094436388900342011-11-08T08:58:00.000-05:002012-01-02T09:26:35.012-05:00

(click any picture to enlarge) Please see Wikipedia for a backgrounder on evacuated tube solar collectors or Google "evacuated tube solar" or "solar vacuum tubes". Much has been written about this method of solar heating that seems to be popular more elsewhere than North America but becoming more so here. My interest is in using the glass evacuated tubes not as a component of a commercial

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com11tag:blogger.com,1999:blog-14977872.post-261421817571157362011-11-04T07:56:00.001-04:002011-11-12T07:56:26.333-05:00

After doing the stagnation test with my DIY solar concentrator a couple weeks ago I had the copper absorber and the evacuated tube used sitting on my workbench. I wanted to get a close look for damage after the interior of the evacuated tube reached a temperature of over 630&degF. You should be able to see quite clearly the discoloration of the copper between the two yellow arrows (click any

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com2tag:blogger.com,1999:blog-14977872.post-48124835261110735552011-10-14T08:55:00.000-04:002011-12-12T11:07:20.609-05:00

I have compared the heating performance of two interesting home built DIY (Do It Yourself) solar collectors: a traditional flat plate collector and a concentrating parabolic trough collector. The tests involved mounting both at the same time in a solar test jig which allows precise aiming of the collectors at the sun's track. Both insulated and non-insulated configurations of each collector

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com3tag:blogger.com,1999:blog-14977872.post-40535956260009983042011-10-10T16:41:00.008-04:002011-12-10T07:13:40.405-05:00

The test today involved measuring the stagnation temperature of both the flat plate and the concentrating solar collectors used up to now in this series of comparative tests. The stagnation temperature is the temperature reached with no fluid flow such as when the pump fails or the owner forgets to turn on the system. It is important for solar collectors to be able to withstand the stagnation

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com2tag:blogger.com,1999:blog-14977872.post-80623332835091960352011-10-10T07:15:00.014-04:002011-12-10T07:27:01.210-05:00

In this test, both insulated collectors track the sun. The flat plate on the left and the concentrating parabolic reflector on the right are coupled to the solar tracker and motor drive on the far right. Although flat plate type collectors are not normally used in a tracking configuration, I wanted to see how the collectors compared when used in this way. All other aspects of the solar test jig

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-30008668234432033732011-10-09T16:52:00.003-04:002011-11-08T05:38:10.203-05:00

In this test, both solar collectors in the solar test jig are insulated. The flat plate collector is fixed in position in the same way as these are normally used. The concentrating parabolic trough collector rotates automatically to face the sun as these are usually used (and the way they must be used for them to operate properly). Details of the insulation for each collector are given in

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-26940064597247493932011-10-08T08:52:00.001-04:002011-11-08T05:37:11.443-05:00

My previous experiments had used a bare mat black painted copper collector tube at the focus of a parabolic trough to capture heat. By introducing an insulator around the collector, it will be possible to reduce heat loss to the air which becomes severe during cold weather or when there is wind. Higher temperatures should also be possible. Evacuated tube solar collectors (click pictures to

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-85615803476652856762011-10-07T10:12:00.004-04:002011-11-08T05:36:26.993-05:00

The flat plate collector that I have been using in my comparative tests was constructed as a 1/2" baltic plywood box with 1" polystyrene insulation glued on the outside of the bottom. I did it this way so that I could use staples into the plywood to hold the aluminum absorber plates in place. The construction of my flat plate collector is described here. Shown above in a bottom view (click to

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-40578485506078352142011-09-29T10:47:00.006-04:002011-11-08T05:35:03.338-05:00

In the previous test, the flat plate collector was fixed in position and it's performance compared to a tracking parabolic solar concentrator. In this variation, the flat plate was ganged to the tracking mechanism used for the concentrating collector so that they BOTH tracked the sun. Flat plate thermal collectors are not normally rotated to face normal to the sun but it is commonly accepted

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com2tag:blogger.com,1999:blog-14977872.post-16443794171117100572011-09-27T11:46:00.012-04:002011-12-12T20:09:40.757-05:00

A test is described which compares a traditional flat plate solar water heater made from copper tubing and aluminum fins to a parabolic concentrating collector. Both types can be home built for significantly less than the cost of commercial units. This test compares how each design heats an identical volume of water side by side in the same sun. You can click on any picture here to see a full

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com2tag:blogger.com,1999:blog-14977872.post-38576212499874425382011-09-23T07:47:00.002-04:002011-09-23T07:52:04.211-04:00

B. Snyder near Tampa, FL wrote to me about a solar heater he is building with his sister to heat a hot tub. They are making fine progress as you can see from this completed reflector picture he sent me. They have decided to build four four foot sections. "Kudos to you for putting this all together! We're having a blast doing this project." he writes. He used Adobe Illustrator to convert the .pdf

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-35367904986748334402011-09-16T11:05:00.015-04:002011-09-19T07:05:30.333-04:00

I had specified what I had hoped to be a readily available, inexpensive and reliable gear motor for the actuator of my DIY tracking parabolic trough solar heater. Having bought and used several of these over the last five years, I had one that needed repair or replacement. It was not turning well and smoke was coming from the motor. So yesterday I did a bit of work to see what had failed and

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-88299887334696094452011-09-13T07:22:00.004-04:002011-09-13T07:38:01.632-04:00

We have a large west facing deck which can become unbearably hot on a summer afternoon. For some time, I had been thinking about a way to create a sun screen to partially shade the deck. The deck is 20 feet wide so the span would have required a fairly massive structure if made from wood. I looked at metal trusses of the kind used on portable stages and exhibits but was discouraged by the high

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-18615910202522393642011-09-12T06:07:00.001-04:002011-09-12T06:08:51.287-04:00

Everyone who builds things needs to find sources of parts. One type of part that I've always had trouble sourcing are small springs. It seems that unless I am buying hundreds of the same type, there just doesn't seem to be many places that sell one or two small springs in an assortment of types and sizes. Recently, before taking a computer printer to the local recycling depot, I spent a

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-5312051640666735572011-09-10T09:27:00.012-04:002011-11-08T05:32:05.029-05:00

I have been preparing to do some comparative tests of different DIY solar collector designs. Accurate temperature measurement is key. Recording a series of measurements over time is also a requirement. Gary Reysa of http://builditsolar.com/ very kindly offered to loan me a data logger. Of course I accepted. Gary has an excellent section on his website about all types of measurments of interest

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-30695835458872124662011-09-01T08:06:00.010-04:002011-09-29T06:25:17.360-04:00

  Occasionally I get feedback from readers of my book showing how they have implemented their own version of my plans, often making improvements for their own situation. Andrew Gray of Austin, TX recently sent me a video showing his own innovation of a dual axis tracking frame. The reflectors pivot to follow the sun and the whole frame pivots to adjust for seasonal variation. The frame is zinc

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-77783116585688104032011-07-19T06:48:00.001-04:002011-07-23T22:03:53.892-04:00

Lachlan M of Australia wrote: I recently bought your down-loadable plans on how to make a solar parabolic trough. Thank you so much for your excellent work. What I find most inspiring is that you have made your many years of research available to anyone with a searching mind who can afford $25. As such you have made available to a huge number of people the technology to collect a large amount of

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com2tag:blogger.com,1999:blog-14977872.post-83398730408912699532011-07-15T16:18:00.007-04:002011-12-12T19:58:52.217-05:00

I have been working on a test jig to allow me to mount and compare different solar thermal collectors of a standard 48x24" size in a tracking configuration. I finally rolled it out of the garage today. The motor drive and the collectors are not yet mounted but the frame is pretty much finished. This jig will allow me to compare two different collectors. The jig will have two independent

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-85925611512774868572011-06-15T08:44:00.001-04:002011-11-08T05:29:34.327-05:00

Peter from Queensland wrote: I have an engineering background & must tell you that your website is perhaps the most professional in content & presentation, well done. My interest is in a domestic solar water heating array for general purpose home use. We are Queensland, Australia (Brisbane are) based, & so in ideal conditions for solar deployment much of the time. I note the success of your

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-27465687184222961912011-04-26T08:34:00.004-04:002011-04-26T08:41:17.322-04:00

Peter wrote: I am really impressed with your solar project. I live in France and like yourself thoroughly enjoy my background in engineering. Some questions: Your troughs are very effective (near on 100% efficiency). How is this possible? Sunlight at zenith provides an irradiance of just over 1 kilowatt per square meter at sea level. Of this energy, 527 watts is infrared radiation, 445 watts

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-72311585499755798322011-03-22T09:35:00.003-04:002011-03-22T09:38:43.503-04:00

Tom wrote: I just bought your doc and have skimmed over it quickly tonight. Very impressed. The ‘errata’ and the QandA links at the end don’t work however and I am interested in them…? I am interested in using such an array (small initially, but scalable upwards) to generate steam, then a steam engine, then a generator etc. First of all, have you done any research on this? Secondly, what is

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-76232783431948031292011-03-11T07:10:00.020-05:002011-03-11T07:24:24.646-05:00

In your book, you mention N-S orientation vs E-W orientation.  Is it correct that with an E-W orientation, the tracking is not as critical as N-S and could be adjusted manually each morning to track the seasonal changes in the sun's angle?Best regards,John I am not sure that I would agree that the tracking is less critical. I think that the main issue with orientation is the efficiency over an

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com1tag:blogger.com,1999:blog-14977872.post-13621681425452713832010-09-11T09:00:00.009-04:002010-09-11T09:18:40.670-04:00

Ahmad from Kuwait wrote: Dear George, I really consider myself lucky to find your book on the internet while looking for information about more secrets of the design of solar heating systems. I already constructed a system of my own design few months ago, which is still in operation for the heating of my indoor swimming pool (18000 Galons), but I was hoping to find information about sun

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-41041302301404002502010-09-08T08:15:00.000-04:002010-09-08T08:15:21.094-04:00

Rob from Australia wrote: I’ve purchased your excellent plans.    I have a question as to how I might go about increasing the solar energy yield per collector by increasing the mirror width – say by 1/6th to 1/4 again) I’d thus need to draw a new parabola – hints on that would be great (I’m not an engineer). This will probably also involve increasing focal distance to the tube. Any quick

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-82367843119453800472010-09-06T16:03:00.004-04:002010-09-08T06:35:00.027-04:00

I've had an interesting ongoing email conversation with a person in Mexico who bought my plans and was very interested in building a solar parabolic heating system for himself. He had been having trouble getting the specific gear motor that I recommend in the plans. In any DIY (Do It Yourself) project sometimes it is necessary to improvise. It occurred to me to suggest to him that he look for a

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-41655091402756926292010-09-05T10:00:00.000-04:002010-09-05T10:00:38.581-04:00

It is the end of another summer of free solar heat for our pool. The DIY Parabolic Solar Heater has worked well again this year. A plan book showing how to build the project yourself has been published and has been selling well - thank you for your support! This project is entirely self funded and your purchase of the plan book helps to support my work. I can report that the problem of back

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-74116820898293249052010-03-30T11:03:00.017-04:002010-05-05T07:10:00.831-04:00

For some time, I have been looking for a small clear acrylic dome to make a sensor housing that has a semi-true spherical viewing window. I have not completed the installation of this new version into my system but I present it here in case you would like to build your sensor housing in this way.Although the previous version, based on the Leviton housing is satisfactory, there are three

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com6tag:blogger.com,1999:blog-14977872.post-91020800797792086012010-03-26T04:50:00.010-04:002010-03-26T05:14:40.200-04:00

Someone asked:Maybe you could address how it stands up to rain, wind, dust, and even (ack) snow? Any problems with birds yet? What is your maintenance cycle like?I've had this system here in southern Canada (43N latitude) for four years now, used for summer heating of a swimming pool. I had expected problems with the cleanliness of the reflectors but my experience has been very good so far.

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-33594686800849319932010-03-25T04:19:00.010-04:002010-03-25T07:25:45.414-04:00

Someone asked:"Have you had anyone build this from machined aluminum other than wood? Obviously wood is the most economical solution for the average home builder but I have access to a machine shop ..."I wrote:Thanks for your interest.The plans just became available two days ago so I don't think anyone has built anything yet except for me.People have asked about aluminum and molded plastic

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com3tag:blogger.com,1999:blog-14977872.post-87581772155463106552010-03-24T06:53:00.008-04:002010-03-25T05:02:01.268-04:00

Someone asked:Do you have any guidelines to figure how many collectors you may need for a given size pool?Thank you for a very good question which I did not address in the plans.There is no specific formula for sizing a solar heater to a pool that I know of.I relied myself on the advice given by the installers of solar pool heaters which is somewhat vague. They say (and they are talking to pool

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-29879919728516983732010-03-19T06:02:00.014-04:002010-03-25T04:37:33.191-04:00

Allen J*** wrote:"How are those plans coming along? Don't mean to be a bother just anxious to see them.ThanksAllen"Hello Allen,No bother at all. Your interest is most welcome.The plans are finished: 90 pages in color, 205 illustrations and pictures, the two large patterns and the hyper-linked document. In February I made another motor drive from the plans just to check that my dimensions were all

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-57609156117284837642010-03-11T09:53:00.001-05:002010-03-19T06:23:38.953-04:00

The plan manual is FINISHED and is out with reviewers. It consists of an 90 page detailed writeup with color photos and illustrations, diagrams and schematics and two large full-size templates. The graphics are hyper-linked to the actual full size drawings and photos (205 in total) that are included. I am making arrangements for a print version and a downloadable version and expect to have

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com2tag:blogger.com,1999:blog-14977872.post-1062172800449505622009-08-22T07:08:00.004-04:002009-08-22T07:28:13.162-04:00

We have been enjoying (finally) some wonderful solar heating weather here in southern Ontario, Canada. With the exception of a couple of violent storms which included lightning and tornados, we have had one beautiful hot day after another.The DIY solar heater has been working flawlessly, tracking the sun when it was visible and providing free heat to our large swimming pool which reached a peak

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-65345170728575340072009-07-28T06:32:00.011-04:002009-07-28T11:33:00.909-04:00

I am using a web cam to capture pictures every 15 seconds over about an hour. I need to work on the focus. A sunnier day would have been nice.Here is one of the original frames. Click to enlarge.What is interesting about this particular piece is that it was mostly overcast with a few bursts of sun.I had thought that the sensor didn't wander when there was cloud cover, but apparently it does. This

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-76435792493690604622009-07-22T11:51:00.005-04:002009-07-24T08:02:42.111-04:00

So far this summer the weather here in southern Ontario Canada has been pretty disappointing, at least from a solar point of view. Here is the forecast for this week for example (click to enlarge). Except for a few beautiful sunny days, temperatures for the last few weeks have been below seasonable norms and the sun has not been seen for days at a time.It will be next week sometime before we see

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-83430183965786314212009-07-14T10:11:00.008-04:002009-07-14T11:25:14.599-04:00

Here is my DIY parabolic solar collector as it looked this morning, turned hard east to catch the morning sun just as it came over the trees which partially block my southern sky (you can click any picture to enlarge it). Although the array is turned 50 degrees from vertical it is not quite far enough to fully focus the sun on the collector tubes. It is about 10am.This is about right, since the

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-55207040341200699662009-07-06T10:30:00.008-04:002009-07-06T11:11:11.272-04:00

As an update to last week's post about the problem with the marking and deforming of the plastic mirrors, I am now even more certain that I have uncovered the cause of the problem.I had been experiencing deterioration of the plastic mirror over time in the form of linear marks that appeared in the mirror and caused it to mark and then warp.I'd shown a picture (similar to the one above) of the

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-87870524891003429252009-07-04T10:52:00.006-04:002009-07-04T11:33:27.902-04:00

I had written last year about the need for limit switches that prevent the motor drive from going too far and of the difficulty of finding inexpensive weatherproof switches that would stand up to outdoor conditions.Any electrically controlled machine needs limit switches. In the case of the DIY solar heater, allowing the motor to drive the mechanism too far could cause various sorts of damage.The

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com1tag:blogger.com,1999:blog-14977872.post-5797746434737735662009-07-03T10:50:00.007-04:002009-07-03T11:57:35.140-04:00

By the end of last summer, I had built and installed a linear to angular motor drive that was vastly superior to the linear push/pull arrangement that I had been using previously.Experience with it has led me to improve it further still in several ways. In this photo (click any photo to enlarge it) you will see the current motor drive. It has been operating for about two months now and this will

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-78532027747625796872009-07-02T08:27:00.014-04:002009-07-02T16:59:17.852-04:00

The reflectors of the DIY Solar Heater can be any thin sheet material 2x8 feet in size.When I started using acrylic plastic mirrors in 2005, they seem to be a perfect candidate: readily available, low cost, lightweight, UV stable, strong and with excellent reflectivity. The mirror surface (a sputter coated aluminum film) is actually on the back surface so that it is well protected from scratches

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-52246548250029522009-07-01T08:29:00.018-04:002009-07-02T17:02:25.757-04:00

Many of you have asked about the performance of my DIY (Do It Yourself) solar heating project.Performance has been somewhat of a moving target since I have been making various changes and improvements but I have enough experience now to provide some detail on the measurements that I have made, to comment on some of the factors that influence the results and to show the calculations that I make to

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com5tag:blogger.com,1999:blog-14977872.post-36498765531802880302008-08-23T12:55:00.013-04:002008-08-23T14:08:24.821-04:00

The solar sensor used here is a small circuit board from Red Rock Energy (redrok.com) that is housed in a weatherproof enclosure from Leviton (leviton.com) fastened to an extension of one of the hangers on the most outboard collector, the one that is in the sun earliest in the morning.Things had been going along quite well since this was installed in this form about two weeks ago. Tracking seemed

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-66909498251203768492008-08-21T05:24:00.017-04:002008-08-23T21:45:14.420-04:00

Two electrical switches wired in series with the drive motor prevent motion past which damage to the mechanism would occur. Here is a picture of the West limit switch in the solar heater at it's full West position. The little roller pushes the arm of the switch up to actuate it and stop the motor from turning the drive screw further in the west direction.All servo controlled systems must have

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-70055881605584323292008-08-14T11:54:00.017-04:002008-08-21T05:23:50.246-04:00

Thanks once again to all of you who have expressed an interest in my project - a DIY solar tracking parabolic collector water heater which is built, for the most part, from common building materials.I am now in my fourth year of working on the development of this project. You can perhaps see from the picture that I now have in place a fairly respectable prototype (my fifth) which is used here for

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-35877498282503976502008-04-20T07:05:00.009-04:002008-04-20T14:31:46.730-04:00

Here in southern Canada, near Toronto, the last winter ice has melted and we have been enjoying some very nice sunny days. I have been thinking a great deal about my parabolic solar pool heater project. There are several main items that I want to accomplish this season:1) Dis-assemble, rebuild and enlarge the solar array with completely new components.2) Move the motor drive to the other end of

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-80626735674759222172008-02-14T07:44:00.006-05:002008-02-14T20:32:38.374-05:00

Dear Joe (and everyone else who has written!)Thanks for your kind note.I AM still working on this project and I did make some progress last year which I have yet to write about.I manufactured about a hundred ribs in preparation to replace and double the number of the collectors in my array to a dozen (each is about a sq metre). I shot video to clarify some of the steps in the process. I

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-1170000194145168492007-01-28T10:52:00.000-05:002007-01-28T20:33:08.436-05:00

Here is the motor drive for the parabolic solar heater on the bench while I was running the yoke from one end to the other using the small DC lab power supply in the background.You can click on any picture here to enlarge it.The DC gearmotor is in the green box to the right. The output shaft of the gearmotor is coupled to the galvanized steel drive screw shaft inside the box. Both ends of the

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-1169902643018285412007-01-27T07:29:00.000-05:002007-01-28T19:11:02.866-05:00

Aiming the entire solar heater array toward the sun is done with one very small and low current 12 volt DC (direct current) gear motor (mounted in the green box). The gear motor output shaft is coupled to a 1/2 inch threaded galvanized steel rod on which rides a small yoke. In the yoke is embedded a 1/2 inch hex nut. As the motor turns the threaded rod, the yoke travels along it. The yoke has a

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-1169555985342541592007-01-23T07:25:00.000-05:002011-11-08T05:19:47.932-05:00

The DIY concentrating parabolic solar heater uses copper or stainless steel pipe for the collector tubes. A metal is preferred for the collector because of its thermal conductivity. This concentrator uses relatively little metal compared to it's effective solar size (aperture, effective area). Metal is an expensive component. The 95% rest of the collector can be made from what is common or that

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com5tag:blogger.com,1999:blog-14977872.post-1158832637476530112006-09-21T05:46:00.000-04:002006-09-21T06:10:18.440-04:00

I had made up a number of four foot parabolic solar reflectors for prototyping the solar heater project.By supporting a single four foot florescent tube at the focus of one of these reflectors, I made a very effective workshop light, shown here illuminating my garage workbench.The same ribs are used as in the longer, eight foot reflectors but with shorter side rails.I haven't done a scientific

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-1158662683216561452006-09-19T06:30:00.000-04:002006-09-19T06:59:46.153-04:00

It's the end of another wonderful summer here in southern Ontario. For the first time, we've managed to heat the pool without burning any propane. (The solar tracking parabolic heater is behind the fence in the picture, click to enlarge). In fact, last month the propane storage tank was removed since we were being charged rental by the propane supplier. I would have liked to have kept it here as

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-1153142756571675502006-07-17T08:48:00.001-04:002009-07-26T17:34:19.453-04:00

Click on any of my pictures for an enlargement or click here to see an animation of the array tracking the sun over a full day in less than a second.My solar parabolic collector array now tracks the sun automatically. It's been working reliably for about the last couple of weeks. The improvement in heat gain is pretty remarkable as I don't have to be around to point the collectors at the sun as

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com3tag:blogger.com,1999:blog-14977872.post-1151232954390110882006-06-25T06:42:00.000-04:002006-06-25T07:45:30.416-04:00

We are swimming regularly now and the pool temperature is holding about 76 degrees F, thanks to the home built parabolic tracking solar collectors and the pool blanket.Here you can see the six collectors currently installed (click any picture to enlarge it). The mirrors are linked together mechanically and pivot around the collector tubes to focus the sun onto the tubes. Pushing or pulling on a

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-1148242700590953072006-05-21T15:50:00.000-04:002006-05-21T16:42:10.896-04:00

By May 9th, we'd had three fabulous sunny days in a row and the pool temperature was up to almost 70 degrees F (starting from about 55).Since then, the weather has turned cold and rainy and there is no sun until next Tuesday according to the current forecast. Almost two weeks without sun.I've diverted to other projects temporarily.Here is the current setup of six collectors waiting for the sun to

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-1147003195531645922006-05-07T07:22:00.000-04:002006-05-07T08:09:37.296-04:00

Spring seems early this year and I'm back to work on the tracking solar pool heater project. Yesterday I progressed a bit further than this picture and had the water flowing through six collector panels.Here you can see the zig-zag path of the water pipes (click on the image to enlarge). The two left collector panels have not yet been mounted nor the flex hoses to attach the collectors to the

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-1136172919057806672006-01-01T22:18:00.000-05:002006-01-01T22:59:21.340-05:00

I had been concerned about getting the parabolic solar pool heater ready for winter.Those of you in a warmer climate probably won't need to worry about what happens when the snow falls. Here in southern Ontario, Canada, there is a good six months when the collectors, if left in their operational position, will fill with snow like they are here. If it doesn't look that bad, consider that its a

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-1135442317255852972005-12-24T11:21:00.000-05:002005-12-26T12:24:52.940-05:00

I believe that just because something is older, it isn't necessarily useless or bad. Sometimes old is good and even better than new. Particularly these days when new has come to mean cheaply made, unrepairable or throw-away.There are many older machines that with a bit of care, repair or restoration can be made to function as well as when they were new, or even better in some cases than the "

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-1128601835484962862005-10-06T08:23:00.000-04:002005-10-06T10:46:37.123-04:00

Collector tubes are the "business end" of this DIY tracking solar concentrator project. The collector tube at the focus of each reflector absorbs and conducts the sun's heat to the water which travels through it.Shown here are four copper collectors and one glass/copper collector that I made to test as a concentrated UV sterilizer.The black coating on the copper is ordinary matte black high

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-1128086196677184512005-10-02T13:01:00.000-04:002005-10-22T05:39:32.046-04:00

Winter is coming here in southern Ontario. The leaves are changing colour and soon will start to fall from the trees. Our swimming pool must be closed up for the winter. The tracking parabolic solar heater project that has been under construction here this summer didn't add any BTUs to the pool during September, although it did give us heat earlier. In the picture (which enlarges if you click it)

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-1125492278127524922005-08-31T12:50:00.000-04:002005-08-31T09:50:17.910-04:00

This is a great rainy day project: making ribs for your solar collectors. You'll need quite a few of them once you've decided to scale-up and make a larger working system. Each eight foot collector needs seven of these. Six collectors need 42 and so on. A general rule of thumb I heard for heating a swimming pool was to have one third to one half of the surface area of the pool in the collector,

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-1124974667529222882005-08-25T12:30:00.000-04:002005-08-25T10:33:56.763-04:00

The hard work of building a solid frame for up to 12 reflectors is pretty much finished now. I'm watching the concrete footings dry in the cool early morning.I took apart the original structure to build this in it's place. In the last couple of weeks, the night-time temperature has definitely had a chill and without even the two reflector system for heat, the pool temperature has fallen to about

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0tag:blogger.com,1999:blog-14977872.post-1122890762476084782005-08-01T11:42:00.002-04:002011-11-12T08:02:48.628-05:00

The DIY parabolic heater uses thin sheets of reflective material gripped along the two long edges in a ribbed frame shaped like a parabola. This forms a rigid parabolic trough when the frame is tightened to snug the sheet into the frame. The reflector ends up looking like a shiny inside-out canoe. The parabola is shaped to bounce sunlight onto the pipe which is at it's focus. The pipe also

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com2tag:blogger.com,1999:blog-14977872.post-1122809876767983252005-07-31T11:16:00.002-04:002008-08-14T16:52:04.009-04:00

This is my "Do It Yourself" project for a high-performance but low-cost modular home-built solar water heater that is largely made with common tools and building supplies.It is also way cooler to have one of these than the traditional flat plate design that most people think about when they consider making a solar heater.Here is another prototype (my third) of the solar tracking heater just

george plhakhttp://www.blogger.com/profile/11832386563569915660noreply@blogger.com0