thermal solar power

I see you are in Nevada...can you afford the water that this will consume? If you have high winds, wouldn't a wind tubine be better, simpler, less dangerous?

Del

Indeed, wind is the cheapest renewable energy source right now, too!

Closed loop system with or without water for the heat exchange and recapture the steam in condenser. Wind zone 6 100mph wind from no one prevailing direction defeats most technology out there. We also have more sun than 86% of the country. Example, Solar One but on a single family dwelling scale.

Wind power won't work well because the winds are too powerful and comes in gusts that hit 100MPH, most wind turbines can't handle this kind of stress, the most vulnerable components are the bearings that suspend the drive shaft. Nevada does have water even though we are the driest state in the union, we have more sunny days than other locations, but I'm thinking about a closed system with a heat exchange medium that can be recovered. The Sterling engine can run with low temperatures but I'd like to "spin" the turbine at a moderate rate of RPM's not unlike a wind turbine. I'm thinking of a hybrid that can generate the heat and store it in something like glaubers salt for release when there is no sun; since the Sterling engine only needs a small amount of heat to operate the system could generate high temperature and higher RPM when there is sun and a lower, slower RPM powered from the heat stored in the salt to run the Sterling when there is no sun. Thoughts?

I see....

Maybe the wind could be utilised to condense the ehaust steam, blowing across cooling coils which are in the shadow of the solar collector?

I'm still not convinced about the wind generator tho'...maybe you'd neen special narrow, fine pitch blades and a super rugged mounting system...

I dunno...good luck with whatever you try ...

(Presumably you have done the solar hot water first, as this is the most cost effective solar energy)

Del

Did the thermo-siphon and storage tank for hot water and it works well. I want a small power plant that can power a house off grid. The cooling will be taken care of in the ground, the system would have subsurface and above surface components. I have designed some "gusty wind" turbines that can handle as much wind as the mount can tolerate, but they are noisy and they block my neighbors view-shed. I want low profile, in-the-ground system design to reduce noise and not block views. I really want to get off grid and save some money, power is expensive and getting more so with add on's like utility "fees" and taxes etc.

The problem with a pressure vessel is the danger of explosion if the pressure gets too much and the safety valve doesn't work. A tight spiral of stainless steel tubing at the focal point of the reflector is safer. The reflector does not have to be round, it can be any shape which focuses the heat along the coil. Turbines require dry steam which means more complications. Better to use a piston steam engine, check Cyclone, Lynx and Green steam engines. If you are a machinist, it is not too difficult to make your own using metal plates, tubes and adapted parts from internal combustion engines. Also look up the Tesla Turbine. It is suitable for the lower temperatures of steam power and can also be built by a competent machinist.

For night time use you could use auto batteries or salvaged batteries from wrecked hybrids with a low voltage system. Or you could build a water tube boiler to provide steam using solid or liquid biofuel. Then you could just fire up the fueled boiler at night and have full power. Then you would only have to have a battery to crank the reflector back around for the morning sun.

The problem with solar power is night and the problem with wind power is no wind. You need to make a hybrid type so you will always have power.

Interesting observations. I agree the coil and different engine types for building a hybrid is the way to go; are you familiar with the Sterling engine? I'd like to avoid battery use except for the realignment of the tracking parabolic. Noise is a consideration, I want these to be able to power an off grid dwelling in close proximity to other homes without causing an annoying sound or visual problem, I'm thinking of putting as much of the system in the ground as possible. Thanks for the reference to the Cyclone, Lynx and Green engines.

Steam power is very quiet. Pedestrians often could not hear Stanley Steamers or Dobles on the street except for tire noise. Sound is not going to be a problem. The only part that has to be visible is the reflector. The use of a biofueled boiler at night solves your battery problem. Your real problem is going to be the boiler and getting past the state and local laws on boilers, inspections and licensing. Plus your local zoning and neighbors may object to the reflector. Good luck.

carrier/utc has modified their large roof top a/c units to run in reverse as organic rankine cycle motors. (see yourownpower.com) the hot side is 70C - cold side is 5C. the delta T req. is only 65C. a very simple solar trough will give 100+++C and the earth one meter down will give you about 12C. why is some able engineer not converting window rattler a/c units for smaller domestic applications just like yours? the power out should come to about 3/4 of the rated power in of the old a/c unit. an ORC motor should be just as quiet as steam. the steam units i am aware of require well over 200C. the working fluid is r132a i believe. these new refrigerants have boiling temps in the 20C range, thereby giving the necessary pressure at lower temps.

i've been on this thread all over the place and have yet to find a qualified, "why not?"

I'd like to hear the answer to Duke's why not

Meantime, Stirling's will be commercially available soon according to press releases from www.infiniacorp.com, the only US maker I have found that seems to be willing to offer less than a completely integrated system.

But if there are other makers I'd love to hear.

Meanwhile I was considering solar home heat followed by power production, so this thread is near to my heart - Stirling off a heatpile is pretty appealing if we can get the issues worked out.

One of them being tracking down the exact delta T s needed, manufacturers are remarkably mum on this.

Emmett

Why go high tech.. Low tech solution, Dark cylinders on the opposite sides of the reflector.

The sun heats the cylinder on the more exposed side and the cylinder fluid expands moving the reflector. the top and bottom can also be done this way; but as you are trying to focus onto a static target I would have a fixed arc of travel. IE. cylinder on left heats up and pushes right side of panel, cylinder on right heats up and pushes left side of panel. Auto Centering and minimal work and easy to repair. you could use, water, brine, used oil, or some highly engineered liquid. I would suggest water so if something lets go you just have to fix the break and refill. The cylinders dont need to be high pressure either. try 3' X 4" black PVC pipe for the cyclinder about 1/3rd water, pressure realease about 3/4rs up connected to a 2" pipe same length as the larger one. A 4" rubber bung attached to a shaft that reaches a hard point on the opposite side of the panel.

There once was a show that had a Nevada guy build this exact device and it was ALL low tech. The guys house was using the sun for heating, cooling, cooking, and power. I wish I could recall the show then you might be able to arrange a visit.

For the pressure vessel look for an old steam engine, its designed for the high pressure steam, May have the drive wheels to allow for power connversion and would be one way to recycle yester-years junk.

Also check out recycling damaged solar panels and old windmills from farms. These items can be used to offset the steamers size and are cheap to obtain. The old windmill can survive high wind gusts and be used as a pump for the steamer and house hold water pressure and supply an evaporator to chill water and the house.

Hope this helps you out.

sounds like your high winds might generate flying sand and pebbles and such that might damage your parabolic mirror?I have another idea that might be useful to you ?If you can get some high end (glass) fiber optic cable you might be able to concentrate the suns energy via a lense or lenses into one end of the (open) cable and that concentrated sunlight will travel down the length of the cable to something resembling the inside of a really big "Thermos bottle" which youve buried underground (for insulation and efficiency purposes) or which youve constructed in the hole and then filled in .Youll also need a solar hot water heater (basically a metal tank painted jet black),which will heat (preferably distilled water as it will cause no scale buildup) to about 180% or so whereupon that heated distilled water will be gravity fed to the subterraenean solar powered thermos bottle a little bit at a time to be flashed into superheated steam ? i dont know if it'll work but it might ?