New Mars Forums

Official discussion forum of The Mars Society and MarsNews.com

You are not logged in.

Announcement

Announcement: This forum is accepting new registrations by emailing newmarsmember * gmail.com become a registered member. Read the Recruiting expertise for NewMars Forum topic in Meta New Mars for other information for this process.

#1 2022-05-22 20:49:26

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 18,066

Trough Solar Collector- Design- Construction- Operation- Maintenance

kbd512 has identified this solar energy collection system as the lead candidate for several projects in development in the forum.

This topic is available for members to collect links, snippets, book suggestions and other resources that might be available.

For SpaceNut in particular ....

Identification of specific companies that provide systems of this type would be helpful.

Patent citations often show configuration and other details that would be helpful in designing fields full of these.

(th)

Offline

#2 2022-05-22 21:23:04

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 29,300

Re: Trough Solar Collector- Design- Construction- Operation- Maintenance

https://www.energy-xprt.com/companies/k … ough-48448

https://en.wikipedia.org/wiki/List_of_c … _companies

https://www.parabolicsolartrough.com/

http://www.solabolic.com/

You need more than just a concentrating reflective system to start with and yes one can build it

https://www.builditsolar.com/Projects/C … rating.htm

The design needs other criteria to be known.

As we talked about in the other topic the solar isolation is a value which must be apart of the equation.

Offline

#3 2022-05-23 06:27:24

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 18,066

Re: Trough Solar Collector- Design- Construction- Operation- Maintenance

For SpaceNut re #2

Thank you for providing a helpful set of links for those who will be studying this technology in detail.

In Sunday's Zoom, kbd512 added details to his vision for a field full of these devices, to make gasoline and diesel fuel.

A key factor in recommending these devices appears to be their simplicity and thus maintainability by skilled trades people over a period of 40 years to start, and for 100 years as an intermediate goal.

Once a flow of sea water to the interior of the United States is started, the flow will become an expected part of the infrastructure, just as highways, railroads and communications lines are today.

(th)

Offline

#4 2022-05-23 09:51:27

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 18,066

Re: Trough Solar Collector- Design- Construction- Operation- Maintenance

For SpaceNut re #2

https://www.parabolicsolartrough.com/

The link above is one of those you posted.

I took a look and realized this is a home scale offering.

Please take a closer look, and let us know if your home/property could support a system of the size shown.

I'm not sure what the throughput is, and the system does not in itself prepare your ground water for drinking, but it ** might ** supply utility grade power for modest activities, or potentially even 12 volt or 5 volt power for charging devices.

Thanks again for your research and posting for this new topic!

(th)

Offline

#5 2022-05-23 19:07:37

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 29,300

Re: Trough Solar Collector- Design- Construction- Operation- Maintenance

The first bad news was in the last of the page in this image.

Map for areas suitable for Concentrating Parabolic Solar Power Troughs
Sun-solar-map-1.jpg

I am in that not so good zone with a design that is not altered to improve performance will not work out.

The second is the need to keep water from the well throughout its processing above freezing night and every day which can not be always gotten from solar.

Yes using heat to boil and then cool to condensed to remove the mineral content would be something that a system would do. To keep the trough pipe from freezing would require changing it from water to a food gylcol and using a heat exchanger to couple the heat being generated to the boiling unit. The other would be to slant the pipe and create a drain back system which needs air venting and more to achieve.

Other adaptation is to increase the size of the reflection surface to the pipe diameter such that you are reflecting multiples of the suns rays onto the pipe by determining the needed up scaling factor. You are still held to the hours of exposure time depending on season for the chosen location of setup. It is possible to slow the flow rate to increase temperature but that will mean less volume will get hot for use.

Making a modified system means moving the trough to change the alignment to gain more hours as it sweeps across the sky in 2 axis not just the one to increase the received energy of the sun as well. This is where a dish works best with a central pan target for the pipe shaped in a loop in restricted application areas.

Offline

#6 2022-05-23 20:50:45

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 18,066

Re: Trough Solar Collector- Design- Construction- Operation- Maintenance

For SpaceNut re #5

Thanks for looking more closely at the Trough design, and in particular, for evaluating it for your location.

The distillation of your well water is a tried and true method that would look a lot like a moonshiner's rig.  There's a cable TV series in the lineup I get to see that features real moonshiners making a great variety of potent spirits they sample on air.  My impression is the TV cable company is (most likely) providing plenty of compensation for the series, so there is (likely) no issue of legaility.  The reason I bring this up is that while the output is slow, it ** is ** steady, and if you set one of those stills running with solar heating, you'd (probably) get a gallon jug of potable water for your trouble.

If you were in an experimental mood, you could use a hot plate to heat a boiler feeding a copper coil cooler. There are inexpensive energy usage devices you can use to measure the total wattage consumed by the device over a period of time.  Even if you never build the solar device, the experiment would deliver a jug of distilled water for (hopefully) less than you pay at the store.

I can give you the name of a vendor of electricity measuring devices if you are interested, but they are easy to find on the Internet.

If you ** were ** to attempt to build a Trough Collector (or better yet buy one ready made) your experiences with operation and maintenance would be quite interesting.

Almost everything this forum discusses is theoretical.  Threre are only a few hints of hands-on activities, such as Calliban with his workshop, and yourself with your automobile maintenance, and possibly one or two other members, such as GW Johnson who spent many years doing hands-on experimentation.

(th)

Offline

#7 2022-05-23 21:42:39

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 29,300

Re: Trough Solar Collector- Design- Construction- Operation- Maintenance

This will apply to mars as well since the planet is covered with iron oxides and water will be with in the dirt layers.

While its just 10 gallons a day that is bought the total would seem to be 10 times that to have processed and more based from the other topics.

I did have an iron removal unit that used back washing which just plugged it sooner due to the iron load that is in the water so I need to move the water first into a settling tank that air rated and adds in salts to aid in the heat processing. It was expensive then and still is.

iron-filter-for-well-water.jpg?w=1536

https://www.uswatersystems.com/blog/rem … well-water

How to Get Rid of Brown Well Water with a Solar Powered Water Filter

https://www.culligan.com/blog/a-guide-t … well-water

https://www.suezwaterhandbook.com/proce … on-removal

https://www.sciencedirect.com/topics/en … olar-still

https://www.frontiersin.org/articles/10 … 31049/full
Advanced Solar Still Development: Improving Distilled Water Recovery and Purity via Graphene-Enhanced Surface Modifiers

http://www.fsec.ucf.edu/en/publications … n-3-80.pdf
Solar Distillation of Water

Offline

#8 2022-05-24 06:21:46

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 18,066

Re: Trough Solar Collector- Design- Construction- Operation- Maintenance

For SpaceNut re #7

Thank you for the links to study, and for the additional detail about your experience with your particular ground water.

Addition of salt to already overburdened ground water seems counter-intuitive, but if I recall an earlier post, you did that to deal with freezing.

But freezing is NOT an issue except during winter.

If you are distilling the water, it would not freeze, and in that case the cold winter air around the cooling coils would accelerate recovery of potable water.

Someone must have suggested adding salt to the water, and that sort of makes sense if you were using a mechanical filter, but then the water has salt in it.

Question: Is the iron in the water magnetic?  Magnetic properties of iron appear to vary depending upon factors I don't fully understand.

If the iron particles in your ground water are magnetic, then magnets at the bottom of the settling tank should help to accumulate the iron suspended in the water.

It should be possible to run an inexpensive experiment to see if a magnet in a tub of ground water attracts the iron.

That link to dealing with brown well water using a solar powered filter looks interesting!

I'd like to see this topic concentrate on the title, as much as possible, but dealing with your pesky ground water is a good challenge for the topic. 

Can you deliver the ground water to a tank in a pipe that is insulated so the water does not freeze on it's way to the tub?

Why not just plan for summer operation and avoid the freezing problem while you develop a working procedure?

You can add measures to prevent freezing if the system works during the summer, and there is enough insolation to spare to prevent freezing.

(th)

Offline

#9 2022-05-24 08:58:02

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 18,066

Re: Trough Solar Collector- Design- Construction- Operation- Maintenance

The YouTube below is a branch from one of the links SpaceNut provided. it shows a solar collector that contributes to heating a house.

https://www.youtube.com/watch?v=sQHXTvz8C6U

The YouTube is a branch from this site: https://www.parabolicsolartrough.com/

(th)

Offline

#10 2022-05-24 16:48:53

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 29,300

Re: Trough Solar Collector- Design- Construction- Operation- Maintenance

Everything we are talking about is not the commercial system that is on the sites and is location custom designed.

A settling tank will need to be sheltered to keep it warm not to mention pipelines must be protected and below the frost line at a depth of 4 feet in the state typically of which ground temperature is what isolate it during the times when we are super cold for days and weeks.

Same holds true for the actual trough and fluid that is used in the concentration pipe, it will freeze over night

Putting a glaze over the opening above the pipe completing a seal will aid in the heat build up and retention, but the real deal will be made with an auto covering that isolates the system during the night to keep the cold out of the system.

Final large holding tank to allow for the days when there is no sun to make distilled water with needs many of the things already listed above. Having a separate hot water tank and loop would if heat is plentiful possible with in the designing of a total system.

Base board heating in this area will need the food glycol mix and I have even seen that freeze if its not of a high enough concentration.

Offline

#11 2022-05-24 17:21:29

kbd512
Administrator
Registered: 2015-01-02
Posts: 7,590

Re: Trough Solar Collector- Design- Construction- Operation- Maintenance

My solar trough design is a polished Aluminized steel stamping (same materials used in modern "cat-back" motor vehicle exhaust system), but with some holes or "ribs" stamped into it (cheese grater design), in order to stiffen the reflector to the point where a low cost / minimum weight welded sheet steel space frame support structure can be affixed to the back of it.

Stamped sheet steel used in motor vehicle exhaust systems are hot-dipped in Aluminum to protect against oxidation / corrosion.  Modern exhaust headers are either ceramic-coated cast iron or stainless steel castings or welded stainless steel sheet ("headers").  All of those options serve the same purpose, but the ceramic coated cast iron resists oxidation better than any common type of stainless.  Even stainless will oxidize / corrode at the temperatures generated.  A very expensive Inconel exhaust system would be required to resist oxidation at the temperatures generated, but a far less expensive ceramic-coated cast iron is the most practical option (why coated cast irons are still used for most exhaust headers).  Ceramic coatings are increasingly common in turbocharged production cars and racing applications because the ceramic thermal barrier coatings also lower engine bay temperatures and the heat that the spark plug wires must contend with, whereas an uncoated metal of any kind tends to require additional spark plug wire protection.  Titanium is only used for weight reduction in racing applications, never for durability, as it will readily oxidize.  Aircraft exhaust systems are primarily welded Inconel or stainless.

The catalytic converter bodies / shells are normally welded stainless sheet steel.  We're not achieving reflector temperatures hot enough to warrant the use of stainless steel, let alone Inconel, so low-cost Aluminized low alloy steel sheet is just fine.  Titanium does nothing for us, and has none of the material properties we're after in commercially pure form.  Pure Aluminum could be lighter than steel and require less supporting structure, but it would also be much more costly to produce, is not truly "available" in the required quantities, and prone to warping and/or cracking as it heats up and cools down every day, especially when stamped into very thin sheets (the primary reason why an Aluminum base metal is non-starter).  The pipe that the solar power is focused onto by the concentrators will need to be stainless steel to resist oxidation, no different than the Rioglass solar trough concentrators.

For the money spent, a polished Aluminum coating will be more durable without an additional oxidation protection layer to protect the Silver coating itself from oxidation, as required by the Rioglass concentrator design.  Gold doesn't really produce the reflectance we're after (works the best over certain wavelengths, but not the ones we need it to), and is even more expensive than Silver for no benefit.

There are an infinite number of minor variants on this basic design that improve performance for increased cost, but we're selecting materials based upon performance achieved per dollar spent.  Ease of manufacturing and recycling are additional design considerations.  These materials are very low-cost, easy to source, very performant (just not the absolute best possible if money and resource constraints are no object), and very easy to repair or recycle when, not if, damaged or destroyed.  We want "the total package".  The materials selected are not "best possible reflectors" or "absolute easiest to recycle" or "lowest possible production cost if maintenance and durability are ignored".  Chasing after perfection in any given area leads to unaffordable and/or impractical solutions, which we must religiously avoid if this solution is to be deployed at "human civilization scale".

Apart from the novel catalysts and production processes that reduce total energy input, there's nothing cutting-edge / high-tech going on here, it's just scaled to the point where we've collected enough solar thermal power to produce energy storage from raw resources, primarily CO2 and water.  By dint of fact that there will be no material shortages associated with this undertaking, we can build out sustainable energy storage in a practical manner that avoids the endless over-consumption and complexity burdens of producing short-lived electronics that have no hope of supplanting hydrocarbon fuels in their present forms.

Rather than punishing people who need energy to do useful things, with idiotic and self-defeating ideas such as "carbon taxes" or "carbon storage" (using lots of valuable energy in a wasteful manner to do nothing economically useful), we've instead turned our insatiable appetite for energy into an endlessly profitable business model that benefits humanity and the environment at the same time.  We draw down excess atmospheric CO2 over time by transforming additional captured CO2 into useful structural materials such as Carbon Fiber and CNT.  We collect badly needed Lithium and Magnesium from sea water as side businesses that support the production of additional batteries over time (eventually leading us to the all-electric future when and as the materials to do that are actually available in the required quantities).  We drop the price of hydrocarbon energy and high strength structural materials suitable for motor vehicles of all kinds, which has the knock-on effect of improving the economy, improving the lives of everyone who benefits from cheap and abundant energy, and we spur on innovation by making aerospace structures less costly to implement.  In short, we use carrots everywhere instead of sticks, thereby allowing the desired energy transition to occur naturally as time / technology / energy storage permit.  If it takes us another 10 years or another 100 years to produce batteries that are like-kind replacements for fossil fuels, then so be it.  We grant ourselves the breathing room in the interim, and improve rather than degrade the standard of living for everyone (which is the only thing that allows them to "care about the environment", because their basic needs have been met).

Offline

#12 2022-05-24 17:31:41

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 18,066

Re: Trough Solar Collector- Design- Construction- Operation- Maintenance

For kbd512 re Post #11 -- thank you for your detailed and comprehensive description of your design!

For SpaceNut ... It seems to me you just stop using the outside system when winter comes.  Worrying about winter is a good way to put off actually accomplishing anything!   The system we are discussing here could work well from later April through November.  If it works well, you could actually save up fresh, potable water to have available in the basement through the winter.

It is now ** summer ** (or close enough!)... You can develop real Universe experience with a settling tank, and experiment with using a magnet to pull iron out of the suspension if that is possible.  I have no idea what would happen, because (a) I've not tried the experiment and (b) I've never run across a report of anyone else running the experiment.  That is such a simple thing to do, you might be the first person in the history of the Human Race to try to find out.

***
Does the description by kbd512 look like something you could do?

(th)

Offline

#13 2022-05-24 18:16:33

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 29,300

Re: Trough Solar Collector- Design- Construction- Operation- Maintenance

Rust (a collection of some iron oxides: ) is virtually non-magnetic, unlike plain iron or most types of steel.

The reason for Water softener salt with rust fighting additives prevents iron deposit build-up, and prevents iron and rust discoloration on sinks, dishes, toilets, cookware, and laundry.

120 degrees Fahrenheit is the safety recommendation against scalding, but 140° is the common default setting. Most experts agree that anything below 120 degrees creates a risk for bacteria to develop inside your water heater from stagnant water, such as legionella that causes Legionnaire's disease.

https://www.varsitytutors.com/hotmath/h … a-parabola

of course shape changes the equation

designs-02-00009-ag-550.jpg

You can also make a combination trough
ese3763-fig-0001-m.png

https://onlinelibrary.wiley.com/doi/ful … 2/ese3.763

https://www.nrel.gov/docs/fy16osti/65228.pdf

An Analysis of the Effect of Molten Salt Thermal Storage on Parabolic Trough Concentrated Solar Power Plant Efficiency

Location on my property is well head is in the shade, would need to create a well house enclosure for a settling tank, pump control units, check flow valves before moving 50 ft or better to lawn would allow an area to place concentration unit no larger than 10 ft x 15 ft at most to make use of. It would not be possible to rotate it for more capture time. This places the water out put yet another 25 ft to bring it inside for storage and use.

The parabolic trough operates at about 75% efficiency and at 495 square foot can collect approximately 270 kWh / 10 hours on a clear day

So from the roughly 75 w a square ft from the sun at 75% means we are getting 55 watts for each square foot.

so 55w x 150 sq ft = 8.25 kw x 2hr  means 16.5 kw hrs will be all that I will get

How Many Minutes To Boil Water Until Safe To Drink
    30 minutes at 160° F or 70° C
    3 minutes at 185° F or 85° C
    Instant at 212° F or 100° C
This solar energy can be used to do work such as to heat water to higher temperatures of 212°F (100° C), killing all bacteria in the water making the water safe to drink.

https://www.energy.gov/energysaver/esti … ter-heater

How to Calculate Time to Heat Water

https://bloglocation.com/art/water-heat … ergy-power

Storage of heat for hot water
https://bigladdersoftware.com/epx/docs/ … tanks.html

https://www.bgehome.com/home-energy-cen … r-heaters/

https://content.ces.ncsu.edu/getting-in … ng-systems

https://industrialheatingsystems.com/Ho … -loss.html

Offline

#14 2022-05-24 18:52:57

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 29,300

Re: Trough Solar Collector- Design- Construction- Operation- Maintenance

food gylcol
https://www.dynalene.com/news/2015/12/f … er-fluids/

You can use properly inhibited glycols at high temperatures up to 350°F. Regular inhibited glycols are generally rated up to 250°F. At temperatures higher than 250°F, glycols degrade severely forming acid molecules.
pipe_burst1-1-300x199.jpg

https://www.engineeringtoolbox.com/ethy … d_146.html

https://goglycolpros.com/pages/glycol-c … protection

Offline

#15 2022-05-24 18:55:07

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 18,066

Re: Trough Solar Collector- Design- Construction- Operation- Maintenance

For SpaceNut re #13 ...

First, thanks for explaining that rust is non-magnetic.  I deduce that your ground water is carrying a burden of iron-oxide particles.

And! Thanks for that comprehensive collections of links to help plan design of a complete system.

I note that molten salt for thermal storage is one of the ideas mentioned by kdb512 in the recent past.

So! In all that work you did, I don't see distillation of water included.  That is by far the safest way to prepare water for human consumption. Anything less means all those dead bodies of microbes are going right into the body of the consumer, along with all the minerals that did not catch on the filter fibers.

For ** my ** money, distillation is most definitely the way to go.

Efficiency of a system might be increased by using cold water entering the jacket around the drip coils to provide cooling, while the hot vapors heat the incoming water as it heads into the distillation apparatus.

(th)

Offline

#16 2022-05-24 20:18:11

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 29,300

Re: Trough Solar Collector- Design- Construction- Operation- Maintenance

That is also why I am looking at the addition of that higher temperature reflecting system as well that will fit with in the designated area.

How to calculate the temperature of a receiving point from concentrated solar power?

It would appear that a Dish would for 1.5m Diameter Parabolic Focal Spot Temperature:700-1000°C at $200 for a unit price.

cfe3318f52b17f7e9d49cc57305cc634733cdd3a_104-100x100.jpg

Offline

#17 2022-05-25 22:02:19

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 29,300

Re: Trough Solar Collector- Design- Construction- Operation- Maintenance

question about the water and well on the property

Granite is the source of the radon that mostly accumilates in cellars.

My well testing has manganese, Hydrogen sulfide gas (H2S) can give water a “rotten egg” taste or odor, this is also the reason for the iron in the water as well from what I recall.

https://www.health.state.mn.us/communit … lfide.html

Water Well Casings: Basics and Material Choice

Well System Componentsdiagramwell.gif

Casing is the tubular structure that is placed in the drilled well to maintain the well opening. Along with grout, the casing keeps possibly contaminated surficial water from reaching the aquifer zone underground and prevents contaminants from mixing with the water.

The most common materials for well casing are carbon steel, plastic (most commonly, but not exclusively, PVC), and stainless steel. Different geologic formations and groundwater quality dictate what type of casing can be used.

Residents in some areas have a choice between steel and PVC, both of which have advantages. PVC is lightweight, resistant to corrosion, and relatively easy for contractors to install.

I think this was the company used to do the work back in 1994 and it was drilled to 280 ft of depth to give it a reservoir to draw from since it had low water gallon per minute capability. Well required from day one a filter and I tried a number of them as well as types.

https://www.juddgoodwinwellco.com/

company for the filter was
https://forestpump.com/filtration/

similar filter type
https://waterfilterguru.com/best-iron-f … ell-water/

The head of the tank had a timer that set the water back washing to clear the iron build up from it.

Offline

#18 2022-05-25 22:10:19

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 29,300

Re: Trough Solar Collector- Design- Construction- Operation- Maintenance

https://extension.unh.edu/blog/2019/01/ … safe-drink

https://www.usgs.gov/news/state-news-re … ding-human

Common Water Contaminants

    Iron
    Acidity
    Hard Water
    Manganese
    Corrosive Groundwater
    Arsenic*
    Lead*
    Bacteria*
    Radon*
    Road Salt
    Nitrate*
    Uranium*
    PFAS AND PFOA*

Will need to follow up if testing results can be found as they may not

Offline

#19 2022-05-30 10:19:30

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 29,300

Re: Trough Solar Collector- Design- Construction- Operation- Maintenance

why do water softeners use salt?

Salt works effectively as a water softener through the process of ion exchange. The truth is, water softeners do not add any salt to the water. The water softening process breaks down the salt to use its sodium. This means that Calcium and Magnesium ions in hard water are exchanged for sodium ions. This is done in the brine tank or softener unit and not about freezing.

https://www.scientificamerican.com/arti … teners-wo/

Offline

#20 2022-05-30 15:51:52

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 29,300

Re: Trough Solar Collector- Design- Construction- Operation- Maintenance

If you are making a reflector you might be able use this product from homedepot
velux-skylights-accessories-ztr-010-0004-64_100.jpg

It is used for a roof top tunnel with diameters of 10" and 14" that comes in lengths of 2 ft increments up to 6ft to curve into a reflector costing $50 to $150 a section.

Offline

#21 2022-05-31 09:10:34

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 29,300

Re: Trough Solar Collector- Design- Construction- Operation- Maintenance

The trough can be used for lots of things.

kbd512 wrote:

Calliban,

I see what I did wrong.  I was using the Wh/m^2/year that the Earth receives at TOA.  That's what always happens when I go from memory, rather than re-verifying what numbers I'm using.

17,100TWh * 2km^2 per TWh = 34,200km^2

34,200km^2 * 1,000,000m^2 per km^2 * 117kg = 4,001,400,000,000kg / 4,001,400,000t

However, I also note that we keep fixating on producing electricity, which is not all or even most of the energy input into the fuel synthesis process.  A standard "nothing special" trough-type solar concentrator converts about 70% of the energy it receives into heat.  Our steel requirement is then 1.6 billion tons.  It's probably less than that since we're not attempting to convert most of the heat into electricity.  The US only uses about 20% of the world's energy supply, so I presume we would need 320 million tons of steel.  However, 1.6 billion tons over 40 years 40,000,000t per year.  That seems doable.

Around 90% of the total global energy consumption is supplied in the form of heat energy, so if we supply all of our gasoline / diesel / kerosene from endlessly sustainable sources, then that pretty much covers everything worth mentioning.  We still need electricity, but if we can supply all of our fuels from scratch, then that's pretty much the entire shooting match.

Offline

#22 2022-05-31 09:11:29

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 29,300

Re: Trough Solar Collector- Design- Construction- Operation- Maintenance

kbd512 wrote:

Calliban,

No, it's not perpetual motion.  It requires an enormous amount of energy input, but straight electrolysis is not the only method used to split water into H2 and O2.  In all the literature I've read about using nuclear power to electrolyze water, it's proposed that elevated temperatures are used to significantly decrease the amount of electrical energy input required.  Is there some reason why that could not also be done using solar thermal power?

If we electrolyze Hydrogen using Hysata's water electrolysis cell, then we would need 5,602.5TWh of input electrical power per year, at 41.5kWh/kg of H2, to produce 135 billion kg of Hydrogen for the 135 billion gallons of gasoline we consume each year.  That's equivalent to about 640 1GWe nuclear reactors running at maximum capacity, all year long.  Something tells me we'd have a hard time managing that, though I will freely admit that the input material requirements are bound to be much lower for nuclear power.

However...

Now I know why those numbers you provided for the weight of steel per square meter of panel surface area looked a bit high:

Eurotrough - Parabolic Trough Collector Developed for Cost Efficient Solar Power Generation

For the ET100 / EuroTrough 100 design, with 545m^2 of surface area, the weight of steel per square meter is 19kg, which is nowhere close to 117kg.  That means 19,000t of steel per square kilometer.  The ET150 design uses 18.5kg/m^2 of collector area.

Exact component mass breakdown, including total mass of steel structure and steel structure mass per square meter:

EUROTROUGH DESIGN ISSUES AND PROTOTYPE TESTING AT PSA

34,200km^2 * 19,000t/km^2 = 649,800,000t of steel or 16,245,000t of steel over 40 years.

650,000,000t * $220USD/t = $143,000,000,000USD (this amount of steel would enable the production of more than double US daily consumption of gasoline / diesel / kerosene)

Even if we used 100% electrical input power and no process heat to split every kilogram of H2 and synthesize the end product, at 50% overall efficiency, then we're not talking about insurmountable quantities of steel over 40 years.  I'm also assuming that we roll out this technology in the US first, so that other nations can learn from our experimentation.  If I presume that the US consumes 550 million gallons of fuels per day, and each gallon of fuel contains about 1kg of Hydrogen, then I need to come up with 550 million kg of Hydrogen, which equates to 23TWh/day or 8,395TWh/year.  If US requires 17,100km^2 of solar trough collectors to cover its own gasoline / diesel / kerosene consumption requirements, or 325Mt of steel.  The US produces about 105Mt annually, so over a period of 40 years that represents about 13% of domestic production.

I don't know for certain what the total installed cost would be, because the prices I've seen are so variable- anywhere between $65/m^2 and $100/m^2, total installed cost.  The costs decrease significantly as more of the same equipment is produced.  I have a document from Abengoa about total installed cost, which I'll post tomorrow.

Offline

#23 2022-05-31 09:11:56

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 29,300

Re: Trough Solar Collector- Design- Construction- Operation- Maintenance

Calliban wrote:

Easy to get lost with so many numbers flying around.  This paper examines materials requirements for two types of solar thermal power plant: tower concentration and trough concentration.
https://www.researchgate.net/publicatio … rmal_Power

Here we are examining the second.  The validity of the calculations that follow rest of the validity of data within this paper.

Whilst there are many inputs identified, two in particular will dominate the embodied energy of the plant: iron and steel.  It isn't clear from the document if iron means cast iron, or if the author is talking about mild steel, which is close to being pure iron.  Likewise, it isn't really clear in the reference if steel refers to stainless steel, low alloy steel, or some mixture of both.  But anyhow, a powerplant producing 1TWh of electric power per year will require the following ferrous inputs:

170,000 ton iron;
63,000 ton steel.

Collectively, that is 233,000 ton of ferrous metal.  One imperial ton equates to 0.9072 metric tonnes.  So that is 211,374 metric tonnes per TWh/year.

In terms of how much power we need to produce the entire world's diesel, I am going with my original estimate of a 50% conversion of electrical energy into chemical energy for the time being (more later).  If that estimate is later shown to be pessimistic, then I will adjust downward the amount of ferrous metal needed.

We need 17,100TWh per year of fixed chemical energy.  So 34,200TWh per year of electrical energy to make it.

211,374 x 34,200 = 7.23 billion tonnes.

That is about 4 years of global ferrous metal production.  If we assume a 40 year lifespan for a powerplant, we need about 10% of existing global ferrous production to be able to maintain a 34,200TWh/year generating capacity.  The plus side is that most of this ferrous metal can be recycled.  In fact, given the size of our demand, we could have dedicated electric furnaces for recycling specific types of steel.

Only 23% of ferrous input is listed as steel, with iron (mild steel?) making up the balance.  I suspect that iron refers mostly to reinforcing iron.  The interesting thing here is that pure iron is a substance that has no particular resource pressures and is easily recyclable in an electric furnace.
_________________________________________________________________________________________

Post note 1. I estimated earlier that in a high insolation climate, each m2 of collector area would generate 500kWh of electric power per year at a 20% conversion efficiency.  If we are raising steam at a temperature of 400°C, then efficiency should be closer to 30%.  So each square metre would generate 750kWh per year.

If we take steel inputs alone (55,700 tonne per TWh per year), it turns out that we need 42.5kg steel per m2 of collector area.  Assuming that some of that steel is used in the powerplant and heat transfer pipework, then we aren't far away from the 19kg/m2 in the collectors alone that you referenced.
_________________________________________________________________________________________

Post note 2.  Regarding the use of heat to reduce the electrical inputs needed to drive electrochemical reactions.  This is the basis behind high temperature electrolysis.  With rising temperature, o-h bonds lengthen, reducing the Gibbs free energy required to break them.
https://www1.eere.energy.gov/solar/pdfs/doctor.pdf

At 700K (428°C) the Gibbs free energy will be 10% lower than its value at 300K.  This implies that electricity requirements for electrolysis decline by 10%.  The other 10% of energy comes from solar heat.  If we use this process, then the solar power capacity we need will be 7% reduced.  The problem is that high temperature electrolysis is an experimental process that introduces problems of its own.  At 700K, the density of water will be much lower, which will impose limits on the current density of the electrolysis cell.  Pressures are much higher and corrosion will be more of a problem.  I suspect that HT electrolysis will achieve a slightly lower power cost at the expense of much greater capital costs at the electrolyser.


According to the reference I used, trough solar requires 250,000 ton cement per GW capacity.  However, a powerplant producing 1TWh needs 65,000.  So we need a 260MWe plant to produce 1TWh per year.

The Solaben power plant in Spain is a 200MWe-p plant, with a reflector area of 1.2km2, covering an area of 3km2.  A 260MWe-p plant would cover an approximate area of 3.9km2.  We need 34,200 of these to make all of the world's diesel.  That amounts to a total area of 133,340km2.  About the same area as Louisiana.

I don't think land area will be a problem.  The world has an ample supply of hot, uninhabitable desert where we can build these plants.  The Sahara covers an area of 9.2 million square kilometres.  We would need to cover less than 2% of it to manufacture all of the worlds diesel.  And it is but one uninhabitable desert region that we could use.  In reality, these facilities would be spread around the Earth's sun belt.

Offline

#24 2022-05-31 09:15:04

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 29,300

Re: Trough Solar Collector- Design- Construction- Operation- Maintenance

The above posts show reference to power scale and how one might provide on there own property sufficient energy at low costs when using the sun and available water and co2 sources to make it happen. If you require hydrocarbon based fuels but even with out the carbon one can still make hydrogen to bottle and use.

Offline

#25 2022-05-31 10:02:13

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 29,300

Re: Trough Solar Collector- Design- Construction- Operation- Maintenance

The size of the reflector to the receiving pipe is what I am looking for in the documents of how to build.
https://www.builditsolar.com/Projects/C … hPlans.pdf

That size is how to determine the amount of heat we might get after an hour of exposure to the sun.
http://www.ffwdm.com/solar/gen2-book.htm

here is the trough build
http://www.ffwdm.com/solar/gen2/BOM-reflector.pdf

theory of the shape
g2-theory-small.jpg

https://georgesworkshop.blogspot.com/20 … intro.html

Offline

Board footer

Powered by FluxBB