Power from steam turbines?

Has anyone implemented a scheme to generate electricity from a steam turbine? If so, can you please
share your experience with the world?


Thanks in advance,
Rui Maciel

Jim Wilkins wrote:

> http://www.john-tom.com/html/SteamPlans.html
>
> Turbines can be made small enough to fit the handpiece of a dental
> drill. I've heard that small ones are inefficient due to tip leakage,
> which becomes relatively less as the size increases. Look at the
> engines for ships and power stations to see the practical size ranges
> for steam turbines versus Diesels.

Thanks for the link, Jim. Although it's interesting, it doesn't have much info regarding steam
turbines beyond a single plan for a toy steam turbine, with no information regarding the power it
generates or even it's efficiency. The site does have quite a lot of plans for toy steam engines
but, again, it provides no info on their power generating capabilities or efficiency.

Are there any resources available on the web regarding steam turbines applications for home power
and the power they are able to generate?



Rui Maciel

Rui Maciel,

Here is a dump of some of the research I did a few years ago on steam
engines both piston and turbine.

My conclusions (for what that is worth) is that if you are building a
single stage plant under 75Hp is way more cost efficient to buy plans
for a piston engine and boiler and have a local machine shop build it.

If you are going to buy go with Mike Brown he has a 3Hp & 20Hp self
starters (2 cylinders). He does not have much competition and his
prices reflect it, but his stuff gets good reviews (what little
reviews there are).

I highly recommend some reading first:
Google Books
Steam_Boiler_Engineering.pdf
Steam_Boilers.pdf
Steam_engine_Principles_and_Practice.pdf
Steam_Power_Plant_Auxiliaries_and_Access.pdf
Steam_Power_Plant_Engineering.pdf

Good Luck.

Curbie


Mike Brown (Finished Piston Enines 1Hp $1200.00, 3Hp $2400.00, 20Hp
$6500.00)
http://home.earthlink.net/~dlaw70/12stmng.htm

Reliable Steam Engines (Piston Plans $50.00, Turbine Plans $50.00,
Boiler Plans $30.00, piston 4-200 Hp, turbine 5Hp)
http://members.pioneer.net/~carlich/RSE/RSEengines.html

Tesla Tubine (Finished Turbine 1Hp $7000,00)
http://www.phoenixnavigation.com/ptbc/turbogen.htm

"Curbie" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Rui Maciel,
>
>
>
> Mike Brown (Finished Piston Enines 1Hp $1200.00, 3Hp $2400.00, 20Hp
> $6500.00)
> http://home.earthlink.net/~dlaw70/12stmng.htm
>
> Reliable Steam Engines (Piston Plans $50.00, Turbine Plans $50.00,
> Boiler Plans $30.00, piston 4-200 Hp, turbine 5Hp)
> http://members.pioneer.net/~carlich/RSE/RSEengines.html
>
> Tesla Tubine (Finished Turbine 1Hp $7000,00)
> http://www.phoenixnavigation.com/ptbc/turbogen.htm


Hmm 1hp engine with 40k BTU waste heat. 1hp=746w=2544 BTU per hour.
2544/42,544= just a hair under 6% efficiency.

On 8/27/2010 3:23 PM, Daniel who wants to know wrote:
> "Curbie"<(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
>> Rui Maciel,
>>
>>
>>
>> Mike Brown (Finished Piston Enines 1Hp $1200.00, 3Hp $2400.00, 20Hp
>> $6500.00)
>> http://home.earthlink.net/~dlaw70/12stmng.htm
>>
>> Reliable Steam Engines (Piston Plans $50.00, Turbine Plans $50.00,
>> Boiler Plans $30.00, piston 4-200 Hp, turbine 5Hp)
>> http://members.pioneer.net/~carlich/RSE/RSEengines.html
>>
>> Tesla Tubine (Finished Turbine 1Hp $7000,00)
>> http://www.phoenixnavigation.com/ptbc/turbogen.htm
>
>
> Hmm 1hp engine with 40k BTU waste heat. 1hp=746w=2544 BTU per hour.
> 2544/42,544= just a hair under 6% efficiency.
>
>

I think I remember that steam was very inefficient....15 percent...??
(piston not turbine)...remember a lot of btu's are lost by heat from
boiler....etc....

Is reason is not used any more....

Also you should know that steam is very, very, very dangerous...reason
they have steam ratings for ships engineers.....you really need to know
what you are doing....do not think is something a home Hobiest should
fool with....

thank you for listening to my thoughts....sno

--
Correct Scientific Terminology:
Hypothesis - a guess as to why or how something occurs
Theory - a hypothesis that has been checked by enough experiments
to be generally assumed to be true.
Law - a hypothesis that has been checked by enough experiments
in enough different ways that it is assumed to be truer then a theory.
Note: nothing is proven in science, things are assumed to be true.

sno wrote:

> I think I remember that steam was very inefficient....15 percent...??
> (piston not turbine)...remember a lot of btu's are lost by heat from
> boiler....etc....
>
> Is reason is not used any more....

Yes, steam engines are terribly inefficient. Steam turbines, on the other hand, are pointed out as
being capable of having efficiencies which even surpass the efficiency of diesel engines.


> Also you should know that steam is very, very, very dangerous...reason
> they have steam ratings for ships engineers.....you really need to know
> what you are doing....do not think is something a home Hobiest should
> fool with....

I see what you mean and you do have a point. Nonetheless, although I'm not a mechanical engineer, I
do have an engineering background (civil, structural). Besides, getting some info on a subject
tends to be quite safe.


Rui Maciel

Rui Maciel wrote:
> sno wrote:
>
>> I think I remember that steam was very inefficient....15 percent...??
>> (piston not turbine)...remember a lot of btu's are lost by heat from
>> boiler....etc....
>>
>> Is reason is not used any more....
>
> Yes, steam engines are terribly inefficient. Steam turbines, on the other hand, are pointed out as
> being capable of having efficiencies which even surpass the efficiency of diesel engines.
>

Yes, but it isn't just the turbine. A modern turbine can, itself, be
very efficient. Power plant turbines have efficiencies approaching 90%.
But that just measures the losses within the turbine.

The whole Rankine cycle efficiency is much lower (30-40% is common).
And to get that you need re-heaters for the turbine. Take steam out at
an intermediate pressure, strip out the moisture and re-heat it back to
near the same temperature as initial.

And feed-water heaters so the condensate you're pumping back into the
boiler isn't cold as from the condenser but pre-heated to almost boiling.

Then, since you've invested a lot of money in this equipment, you might
want to start thinking about chemistry control to prevent corrosion from
eating through the heaters.

There's a reason that home-project steam plants aren't very efficient, cost.

daestrom

Morris Dovey wrote:

> If you're willing to widen your search to include other external
> combustion engine flavors, you might consider Stirling engines - and, in
> particular, the fluid piston fluidynes.

Thanks for the tip, Morris. I had initially discarded this type of engine because after looking
into it I was left with the idea that their use was basically limited to gimmicky, non-power
generation applications such as small table-top toys. After a bit more reading I've noticed that
although their efficiency is rather low, there are quite a lot of qualities that make these sort
of engines an interesting option to consider.


> Do civil engineering students study thermodynamics? [Be careful how you
> answer. ]

I don't see why any civil engineering student wouldn't be able to study thermodynamics, although
it would be something that they would have to do in their spare time. According to the courses
I'm familiar with, the typical civil engineering course includes an introductory course on
thermodynamics and then puts a bit of emphasis on fluid mechanics. That is, obviously, not
comparable with the emphasis that mechanical engineering courses place on thermodynamics, even
when ignoring specific courses covering turbo-machinery.

Nonetheless, this is a bit of a non-issue in this particular discussion. I don't plan to build a
power plant from scratch, which would be quite a hefty task to pull off. All I want is to get
information about the available options to generate power in an off-the-grid scenario. Solar power
is a nice option, provided that we focus on solar-thermal. That option becomes even more
interesting if it's possible to complement it with biomass. Yet, it all boils down to (pun
unintended) how we convert heat to mechanical energy, and there is virtually no relevant info on
this subject.


Rui Maciel

--One thing to know about steam turbines: they don't equal steam
piston engines in efficiency until you get up to about 52hp; this equates to
about 500 square feet of heating surface with wood firing or about 350
square feet of heating surface with oil firing. I'm thinking you'd need a
pile of heating surface for solar conversion and that would mean a *huge*
array: several acres at least.

--
"Steamboat Ed" Haas : A human without a critter
Hacking the Trailing Edge! : is incomplete..
www.nmpproducts.com
---Decks a-wash in a sea of words---

Morris, thanks for the kind words.

Rui Maciel,

>All I want is to get information about the available
> options to generate power in an off-the-grid scenario.
> Solar power is a nice option, provided that we focus
> on solar-thermal. That option becomes even more
> interesting if it's possible to complement it with biomass.
>Yet, it all boils down to (pun unintended) how we
>convert heat to mechanical energy, and there is
>virtually no relevant info on this subject.

Alternative energy is called "alternative" for a reason, commercially
speaking, there is a more efficient way to accomplish the same thing,
so when you set out to produce energy on a home-scale you
automatically lose the more efficient fuel, economy of scale, and
engineering efficiencies that the commercial folks have developed.

My point here is, it's cheaper and probably will lead to a more
successful result if you allow your location's resources and
requirements dictate the best source(s) of alternative energy and not
go into the problem with a preconceived solution. After all, we are
talking about finding the best, less efficient energy alternative and
we are staring with some significant disadvantages.

A sound understanding of your location's climate pattern (solar, wind,
rain, and temperature), your site's land, water, and topographical
resources and your personal energy requirements is, in my view, the
first step of building a successful off-grid plan. One size (or plan)
does not fit all, just using the solar-thermal and bio idea as an
example, a successful solar-thermal and bio plan would look very
different in Montana, than a successful plan in Florida. Different
resources and requirements.

I've been studying the combination of solar-thermal and bio, but that
simple notion covers a lot of territory from anaerobic (in the absence
of oxygen) decomposition of bio-mass for methane, steam reforming of
carbon for hydrogen, woodgas (or Syngas), ethanol, and bio-diesel, not
to mention solar collectors or concentrators.

I don't know what your resources, requirements, or plans are, but I
may have found some of the relevant information you've been looking
for.

Curbie