solar sterling engine generators

[cssolar]

At last it look like there will be an alternative to pv battery setups,

an interesting company coolenergy is developing a low temperature sterling generator !! called the solar heart engine.

what a great idea ! cant wait for it to be commercially available


Any body else tried to generate electric from low temperature thermal heat ??


I have seen the large parabolic high temp types that track the sun , but don't think they are viable for home use.

Tony

[Sunking]

Although Sterling engines do exist and are real, they are extremely expensive and complex engines. No they would not last longer than a good 5 year battery.

Sterling engines require an external heat source like diesel oil, fuel oil, nuclear heat, natural gas, wood, geothermal heat source, or something on that order to do any useful work. They also need a massive heat sink like a large lake or ocean. It is just not feasible or practical on any small scale as they are extremely complex.

[Mike90250]

....

I have seen the large parabolic high temp types that track the sun , but don't think they are viable for home use.

Tony

That company just went under too ! Scottsdale, ArizonaStirling Energy Systems Inc

[russ]

Here are a couple of concentrators - 1 is for hot water only (Georges Workshop) while the second is for PV power plus hot water

1) http://georgesworkshop.blogspot.com/
2) http://www.absolicon.com/

[cssolar]

sterling generators

Ok I admit the technology still has a way to go .

But I am sure solar thermal to electric is future renewable

large parabolic setups are to expensive for domestic use, good solar water heating technology exists,

hot storage is not a problem so all that is missing is the device to convert heat into electricity.


Tony

[russ]

Bit of a problem with that - very inefficient - better to stick with hot water.

Storing the heat - still a work in progress - not ready for industry let alone residential use.

[cssolar]

sterling generators

Hi Russ,

As I said , still a way to go !!

hey my swh Tank is full and reading 89 degrees c, tomorrow morning it will be about 80 degrees c

so I don't see hot water storage for night use as a problem,

[Sunking]

Ok I admit the technology still has a way to go .

Huh? The sterling engine is fully matured and old as the steam engine of 200 years ago.

hot storage is not a problem so all that is missing is the device to convert heat into electricity.

Tony what you are missing is it takes a huge heat sink like an ocean or large lake. The huge differences in temperature extremes is extremely hard on the engine and lubricants cause rapid accelerated corrosion and mechanical stress. These are the reasons they are not used.

A Sterling engine operates just like a internal combustion or steam engine. They all convert heat energy into mechanical energy. The difference is the sterling engine requires a massive heat sink. You could make one work on a boat, but they were never used because it was too unreliable (frequent breakdowns and constant maintenance), expensive and complex. That is why steam engines were used in the 1800's and not Sterling. It is much more efficient, less expensive, and easier just to use a heat source fuel (name your poison) to generate steam, turn a turbine which turns a generator which generates electricity.

The Sterling Engine is an antiquated relic from the past like steam locomotive trains. They belong in a museum.

[cssolar]

low tech

Hi Dereck,

I live is a small village in Spain called Agost it is famous for pottery , they have been using very old technology
for solar cooling of water for 100s of years.

drinking vessels are made from the local clay which is slightly porous, when filled with water and left in the sun water evaporates through the clay and cools the water down.


maybe this old tech could provide a good heat deferential for a new generation sterling engine ???

Tony

[Sunking]

Tony what you are going to have to grasp is the Law of Thermal Dynamics. Heat is measured in BTU's, and BTU's can be converted into mechanical energy minus losses, and mechanical energy can be converted to electrical energy minus losses. Once you understand that and how many BTU's you have to generate you will understand the challenge. A steam powered turbine is the most efficient way to generate electricity with heat energy. The heat source can be anything like I said, just choose your poison. But to use a sterling engine requires a place to transfer all the heat very quickly and it has to be massive.

One gallon of diesel fuel at the typical conversion efficiency of 35% will generate roughly 14 Kwh of electricity.

I am not trying to tell you it cannot be done, but I do not think you understand the scale of what it takes to do it. To make a steam turbine generator to burn 1 gallon of diesel fuel per hour will be about the size of a large suitcase you can carry. To do it with a sterling engine would be the size of a car and require a fairly large lake. That is using diesel fuel as the heat source. Now you want to use the sun to do that right? well you need a huge solar mirror array covering several thousand square feet with tracking or someway to concentrate the heat to a small area. Of course one problem is the sun only shines for a few short hours, come night fall you go dark without power.

If you make pottery to make a living, how are you going to compete with your neighbor using diesel fuel selling his clay pots for 1/10th of what you have to charge using a RE source of fuel? Simple you will not, you will go bankrupt and be out of business because you cannot compete.

[cssolar]

Hi Dereck,

I know it cant be done at the moment but I think possibly in the future !!

I have had a response from cool energy and they are developing a system

take a look www.coolenergyinc.com

I am not a clever person ( didnt pay too much attention at school ) but I remember my physics teacher saying energy cant be destroyed it just changes from one form to another.

so maybe one day some how we could get the heat energy out of the water and change it to electrical energy.

Tony

[Mike90250]

... they have been using very old technology
for solar cooling of water for 100s of years.
drinking vessels are made from the local clay which is slightly porous, when filled with water and left in the sun water evaporates through the clay and cools the water down..

And if you leave it in the shade - it will get cooler, faster.

Try the hot water in the ice cube tray trick - it turns to ice faster than cold water, but you only get half the cubes because of evaporation.

[cssolar]

water cooler

Hi Mike,

I will try that !

I have got one these vessels that is designed for animals to drink out of, it is great holds about a gallon of water, ideal when we go out for a day, the dog has plenty of cool water to drink !!

[Mike90250]

There are many "clay pot" refrigerator designs, and they all rely on unglazed clay and water wicking thru them and evaporating. They have a 2-3 year life, depending on inpurities in the water that plugs them up eventually. portable water jugs sometimes have burlap or felt wrapped around them, so the evaporative cooling keeps the water cool.

[cssolar]

Hi Mike,

The ones produced here are white unglazed, with a circular carrying handle on the top and two spouts, one for filling and one for pouring.

a while back I was in the local builders yard and I saw a load of them, I was told they are still used on building sites, for the workers .

beats warm coke !!