Building a Stirling Engine Heat Pump, Anyone ? [Archive]

Ace-One

03-06-2003, 07:53 AM

I find the concept interesting, especially if it can be made as efficient at stated in Airspitirt's article (http://www.procooling.com/articles/html/stirling_cycle_cooling_-_the_f.php).

I tought about building one myself, but I have no idea how to construct a piston tight enough to keep the cooling gas in place. Guess we're talking semi-high pressure Helium or Nitrogen here, right ?

Is anybody playing arround with this ?

gmat

03-06-2003, 09:10 AM

I've seen various historic and scientific reports on stirling engines. What i heard was no-one made them anymore, due to lack of industry interest or funding, but all of sudden people all around seem to rediscover this *old* concept (what was it already, around 1830 ?).
IIRC Philips held the rights on stirling engines, but never pushed the research, and eventually stopped funding it altogether. At a time people tried stirling boat engines, and even car engines (GM tried it), and poof, nothing.
It would be thrilling to get a hold of one of those puppies, for silence afficionados it would be an ultimate solution !

As for building one yourself, good luck, it has been a challenge for engineers for 1 century and half already. The high pressures and tight tolerances require top-quality materials, or leaks / cracks will develop. No wonder those things are expensive as hell.
BTW they can work with just any gas, including "common" air.

Ace-One

03-07-2003, 06:04 AM

Yeah, LOTS of links on the web.

http://www.keveney.com/Vstirling.html
http://www.dynagen.co.za/eugene/stirling.htm
http://www.sesusa.org/DrIz/index.html
http://www.bekkoame.ne.jp/~khirata/english/make.htm
http://www.stirlingengine.com/kamen/dean_kamen_patent.html

I haven't evn had time to read through all those, and there are plenty more, I'm sure.

Well, if you have some insights, post'em !

gmat

03-07-2003, 09:23 AM

!!! The patent application (last link) is frightening. How did the patent office accept that crap ? They patented a century-and-half old technology...
Reading through the patent description (full of BS and long words meant to lose the intended readership, ie the patent office) i fail to find something new... Philips and GM did all that was possible about 50 years ago

(edit) i need money. Gotta patent the steam engine and reclaim money to nuclear powerplants (which rely on steam engine principles)

airspirit

03-07-2003, 02:48 PM

There are design plans you can get on the internet. You need to manufacture them to pretty tight tolerances, though ... I hope you have a full fledged machine shop.

Honestly, I'd wait a year until fridges containing these things hit the market. It'll be a cinch to do it then.

g.l.amour

03-07-2003, 03:19 PM

whoaah,

are u sure mainstream technology is only a year away airspirit? i don't know to much about the topic, but considering that the tech has been there for a couple of centuries makes me wonder why now it would break through all of a sudden.

BrianW

03-07-2003, 07:32 PM

Concept to manufacturing is abig step and can take a long time depending on many factors inclusing but not limited to , manufacturing processes, materials technologies, demand and need.

I am not sure why it has taken so long to come to production.

Brian W

gmat

03-10-2003, 05:39 AM

Originally posted by BrianW

I am not sure why it has taken so long to come to production.

Brian W

Historically, lack of suitable materials and manufacturing process. The quality of steel needed for the cylinder, and the tight tolerances (not to mention seal materials) are all part of recent history.
During the 20th century, lack of interest from the industry, then intellectual property rights held by a company who was thinking about it as a "gadget", and hostility from piston engine manufacturers all held it back. Look at the Wankel engine (now held by Mazda), it's the same story.
A few companies opened its grave and brought it back to life, through energy production, very recently. Let's hope we'll see more cooling products based on it.

airspirit

03-18-2003, 02:00 PM

The reason that it's been pounded on for the last couple of years is for refridgeration purposes in third world nations, where a portable unit powered by a solar cell/battery combo could be used off-grid. They are also being pushed in the EU because of tight controls of the gasses used in phase change fridges. Also, since they use less power, the greens are after this in force. It is expected that stirling powered fridges should be appearing on the market this fall according to certain stirling development companies and appliance manufacturers.

Check this out:

http://www.lge.com/about/news/news_read.jsp?cpage=1&searchstring=&seq=1700

This is using stirlings for http://www.sunpower.com

The technology is almost upon us. I am hoping to use this tech in a project next year ... may the appliance gods bless us all.

gmat

03-18-2003, 04:05 PM

Yeah i've seen them on geothermal powerplants, as well.

surge

03-20-2003, 04:46 PM

Hi all,

Closed cycle refrigerators using helium gas and a modified Stirling cycle (tradename Displex, and pioneered by Air Products) have been used for some time, and can get to temperatures as low as 6K (-267 deg C!!). There is a monster one (4.5 kW) that will dissipate 100W at -196 deg C (liquid nitrogen temp). Stick that on your CPU!! Kind of expensive though....

see

http://www.datacompscientific.com/Cryogenics/ARS3.PDF

airspirit

03-20-2003, 05:07 PM

Expensive models have been around for years. What we're talking about is units that would be affordable for us hardware hacks to mess with.

surge

03-20-2003, 05:14 PM

Fair point! I was just trying to show what was technologically possible. Maybe I should have kept the old Displex we had in the lab and not thrown it out a couple of years ago..!!

pilsn3r

03-23-2003, 04:59 PM

sterling motors are in use...
http://www.kockums.se/Submarines/gotland.html
look at Propulsion:
Single-shaft, diesel-electric and Stirling Air Independent Propulsion

(edit): read the thread a bit to fast...

j813

04-07-2004, 01:55 AM

What's the update on this tech?
Airspirit I'd just like to know if you ever tried to make one of this system?

pelle76

04-07-2004, 02:12 AM

I saw a webshop a while ago that sold small sterling engine gadgets that run off the heat from a hand. You just needed to give it a push in the beginning and then it ran by iteslf as long as you had it in your palm.

Pilsn3r: It takes swedes to make something like that, right :D

WAJ_UK

04-07-2004, 03:23 AM

I looked into it a bit a few months ago and the guys here http://www.globalcooling.nl/ seemed to be quite close to making affordable refrigeration units using the stirling cycle. I noticed that their website hadn't been updated since last September so I tried emailing them to find out what the progress was but I got no response. Which isn't really a good sign

Brians256

04-07-2004, 01:15 PM

I don't see any plans on the net that would help build a heat movement stirling engine. I see some plans that are for toy stirling engines driven by heat, though. I want plans for the equivalent of a heat pump capable of moving 200W of heat, of course!

pelle76

04-07-2004, 01:28 PM

Brians256

04-07-2004, 01:31 PM

Its just a matter of size :)

Really? How well do the tolerances scale up? What kind of clearance do you need between the cylinder walls and the pistons? What design would be best for moving that much heat? Do you stick with dry air or go to hydrogen for efficiency or helium for safety? What pressure do you need? How do you tune it? In particular, can I build one with repeated application of doughut bribes to the folks in our machine shop if I buy aluminum and stainless steel stock?

I've got lots of questions!

pelle76

04-13-2004, 04:41 PM

Found this (http://www.bobblick.com/techref/projects/stirling/stirling.html) guy who made his own sterling engine

Brians256

04-14-2004, 08:43 AM

I want plans for a cryocooler. It looks as if it might be difficult to fab, though.

JWFokker

05-30-2004, 03:00 PM

Maybe someone should let Swiftech or some other PC cooling company and let them know there's quite a bit of interest in this. Though a relatively small company like Swiftech would probably charge $200 easily for a small engine, considering they charge $50+ for a machined block of copper.

amd 64

06-16-2004, 09:54 AM

i am planning to build a stirling engine but i'am looking for formules..
and materials, i don't now how big the cilinders must be, to cool down (circa) 200watt @ -160 -190. mayby you could help? :)

in that link:
http://www.procooling.com/articles/html/stirling_cycle_cooling_-_the_f.php
says that you can buy a small stirling engine that uses 8-9 watt and cool down to 5 graden. where can i buy this

(i am not so good in englisch sorry :) )

cristoff

06-17-2004, 03:30 PM

more info
http://www.janis.com/p-stirling.html

cristoff

06-17-2004, 03:36 PM

http://www.apdcryogenics.com/products/

Juggernault

01-23-2006, 01:37 PM

Any news about stirling engines? the article is older than 3 years!

bobo5195

01-23-2006, 05:03 PM

Stirling engines are over 100yrs old they are old tech.

As a pump they or removing heat from the system there are far far better means. If you want a really efficent water pump use a car turbo or something in a custom casing.

Compressed gas high tolerences are not the words that make a good DIY project.

There is some modern usage of stirling engines though for micro power in places like the UK with ample gas supply to homes. Basically you whack a stirling engine onto a bolier. The high efficentcy of a stirling engine is a good assest if you need to generate electricity cheaply and cleanly. Of course for generating electricity without an ample supply of high grade heat for a stirling engine is pointless and wasteful but still it could lower your electricity bills and its better than the alternative (closed cycle gas turbine aka mini jet engine which is expensive and not good at variable loads).

Long Haired Git

01-23-2006, 06:39 PM

Zero moving parts is ideal.
Rotating parts is next best.
Reciprocating parts with gas-tight seals? Never going anywhere methinks. Like peltiers, they're good for showing frosty cold-ends when there isn't 140W of over-volted, overclocked dual core Opteron stuck on one end.

The tech I want to see is the one with that special material you put on a disk and pass through a magnetic field that somehow heats/cools. Rotation not reciprocation, and no seals. By the time it comes along, I wonder what wattage CPUs we'll be dealing with?

gmat

01-24-2006, 02:14 AM

LHG actually stirling engines move slowly enough so they can work like 20 years maintenance-free. They are used to power some boats (river freighters) and as cheap, reliable auxiliary power generators.
Their main drawback is poor power-to-weight ratio, which makes them unsuitable for moving vehicles lighter than freighters, as Cadillac found out (iirc it was them who tried a stirling-powered car).
Now about using them as a heat pump... this is a different story.

billbartuska

01-24-2006, 08:27 AM

http://www.coleman.com/coleman/ColemanCom/subcategory.asp?CategoryID=8595

Joe

01-24-2006, 09:04 AM

Stirling engines for cooling would be very nice in PC's... Quiet, efficient.

Theres an article on the site already about stirling cooling of PC's done a couple years ago.

bobo5195

01-24-2006, 10:33 AM

Long Haired Git

01-24-2006, 11:40 PM

There's a company after my own heart, Coleman.

The esky there shows a delta-T of 70°F which will do me!

Naturally its just keeping something that is cold just as cold when inside an insulated container. How it handles 140W of overclocked, overvolted Opteron is the real question. How it handles full-throttle operation 24x7 is another.

Someone buy one and find out!

Brians256

01-27-2006, 05:45 PM

Everything i heared was that stirling engines are awful as cooling device. A stirling engine vs a heatsink is like comparing a stream to a man with a bucket.

Sitrling engine effeicentcy is at least a linear relation with temprature. 10c is no where near enough temprature gradient for them to work with properly.

Only 10C dT? I would assume that anyone using a stirline heat engine in their PC would be going below ambient. Where have you heard that stirling was a bad cooling technology? The problems I've heard are 1) MTBF and 2) mfg cost. Not efficiency (but I don't know how well it works with different dT's).

bobo5195

01-27-2006, 07:09 PM

Thermodynamics professor siad to me. As he put "stirling engines are shit" he was talking in the case of power generation though.

if you want to remove heat from a system use a peltier or refigerant system it's more efficant once costs and things (size etc) are included.

MTBF and mfg costs are key costs excluding them excludes alot of stuff. MFBF is ultimately a small thing as they are basically IC engine pistons which can last for yonks if well designed nut are big stirling engine built to good tolerences is quite expensive and you have to run these things.

I swear that the efficantcy of the system is due to temp differential so at PC kind of tempratures stirling engines of useless. Of the top of my head the only arguement i can support this with is (p2/p1)=(T1/T2)^(gamma -1 / gamma). Where gamma for air is rougly 1.4. So to get a good presure then you are going to need alot of pressure to get things going. I belive their efficantcy is directly linked to pressure by second law of thermodynamics arguments but i need to read a book on this subject. Ultimately a $30 peltier can destory any stirling engine for the purpose you are after. there would be alot of losses trying to convert work to a temprature differential.

TerraMex

01-27-2006, 07:32 PM

while we're at stirling engines (http://en.wikipedia.org/wiki/Stirling_Engine):
http://www.physics.sfasu.edu/astro/courses/egr112/StirlingEngine/stirling.html
it's ghetto time.

about it's efficiency ... well, since it's being researched to be used in veichles and currently used in low signature submarines , can't be that bad.

bobo5195

01-27-2006, 07:41 PM

researched into definitly does not mean that it is a good tech only a possible approach. given it is still at the research stage after decades is probably a bad indictator. As an example car industries adiabatic engines (0 heat transfer) and 2 stroke engines have been under research for years and had billions of $ put into them and have never reached developed product stage.

low signatures submarines is because an external combustor is quiet.

TerraMex

01-27-2006, 07:49 PM

but has to be fuel efficient and resonably fast,
if it takes too much space, or too long to reach anywhere,
defeats purpose on such subs.

bobo5195

01-27-2006, 09:13 PM

for subs primary consideration is noise.

Engines of this sort can be very fuel efficant if large and expensive. The alternatives like gas turbines are normally cheaper and more eifficant.

if you want range on a sub you go nuclear but that is the kind of place where you would use stirling engines as steam turbine plant is very loud. The energy input for nuclear is enough that it can be done econmically and efficantly by using very high temps.

As cooling and for most normal uses there is no point. It will get comprehensively beaten by normal IC engines and for external combustion (low pollution) there is alot of gas turbine tech that is far far better for the heat input. As a heat pump its too large, too expensive and frankly not very good. refrigerant tech can get you better temps with focues cooling.