Search found 308 matches

by Aviator168
Wed Feb 01, 2017 7:36 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Disappointing
Replies: 34
Views: 16162

Re: Disappointing

Where is the link? Here is about external combustion engines. The heat can be re-capture many times. You just have make some compromises, especially in size. One of the biggest challenges of stirling engine is the burner and the outside heat transfer area. Just do some exchanger calculation and you ...
by Aviator168
Tue Jan 31, 2017 7:52 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: Disappointing
Replies: 34
Views: 16162

Disappointing

Anyone else can verify this? I did some calculations and they made sense.
http://file.scirp.org/pdf/ENG_2015121717392471.pdf

Note. They are talking non-pre-heated air. A professional stirling engine will always has a pre-heater for air.
by Aviator168
Tue Jan 31, 2017 5:34 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: 2 KWh LTD Stirling Engine
Replies: 28
Views: 18002

Re: 2 KWh LTD Stirling Engine

Alfista, while you are at it. Do you have an estimate the amount of work can be extracted from a heat engine in cycle? For example, if you manage to inject 100 J of heat into the working fluid, how much work can be extracted with a cylinder and a piston?
by Aviator168
Mon Jan 30, 2017 6:51 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: Friction in a Small Alpha Type Engine
Replies: 4
Views: 3783

Re: Friction in a Small Alpha Type Engine

thanh-cuibap, yours is gamma engine; the OP is talking about alpha.

robwallbank, if you use diaphragm for the pistons, the friction would be so small that you can't even measure it.
by Aviator168
Fri Jan 27, 2017 1:47 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: 2 KWh LTD Stirling Engine
Replies: 28
Views: 18002

Re: 2 KWh LTD Stirling Engine

When you lower the temperature, everything has to get bigger in size and it costs a lot of energy to move them back and forth.
by Aviator168
Fri Jan 27, 2017 8:56 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: 2 KWh LTD Stirling Engine
Replies: 28
Views: 18002

Re: 2 KWh LTD Stirling Engine

Yeah. You need to account for all the pumping lost. Force oil and water through those small tubes takes a lot of energy. However, they can still claim high efficiency since the heat rejected by the engine is being used to heat the swimming pool. I am currently building a model LTD engine, with two a...
by Aviator168
Fri Jan 27, 2017 7:38 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: 2 KWh LTD Stirling Engine
Replies: 28
Views: 18002

Re: 2 KWh LTD Stirling Engine

If you look at Fig.1 12 is the heater, 11 is the regenerator, and 13 is cooler. The displacer being such smaller volume; it is indeed a very smart design. BTW. You can get rid of the water/oil pumping mechanics; instead, use electric pumps with electronic control. You can also, change design a bit a...
by Aviator168
Fri Jan 27, 2017 4:13 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: 2 KWh LTD Stirling Engine
Replies: 28
Views: 18002

Re: 2 KWh LTD Stirling Engine

Hey Ian. This is by no mean, is not impossible. The biggest challenge is the displacer. If the stroke is 5 cm, you are talking about a displacer with a diameter of greater than half a meter. Making that thing light enough is a challenge, not impossible.
by Aviator168
Thu Jan 26, 2017 9:11 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: 2 KWh LTD Stirling Engine
Replies: 28
Views: 18002

Re: 2 KWh LTD Stirling Engine

Actually, the Sunpulse is simpler than the scale up LTD. The big thing you see moving up and down is actually the power piston. Assuming you can get 20% mechanical power, @ 180rpm, you are going to need to heat at least 10 grams of air up by 100 degree and cool it down again in every cycle. As to ho...
by Aviator168
Mon Jan 23, 2017 1:45 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: Multiple tube Thermal Acoustic engine
Replies: 11
Views: 5680

Re: Multiple tube Thermal Acoustic engine

That's excellent derwood. Like to see a load on it to measure the power output.
by Aviator168
Sat Jan 21, 2017 8:52 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Trying to make an Andy Ross B20
Replies: 17
Views: 9923

Re: Trying to make an Andy Ross B20

Trevor, I don't want to get into calculations of aerodynamics forces and heat exchanger here, but the main force blocking working fluid transfer has to do with the size of the cross section area. One thing though, the kinematic viscosity gets smaller with increase of density. (https://en.wikipedia.o...
by Aviator168
Fri Jan 20, 2017 11:57 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Trying to make an Andy Ross B20
Replies: 17
Views: 9923

Re: Trying to make an Andy Ross B20

Ian, it looks like you can move the heater a bit lower.
by Aviator168
Fri Jan 20, 2017 4:28 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Trying to make an Andy Ross B20
Replies: 17
Views: 9923

Re: Trying to make an Andy Ross B20

Did you get more HP out of it when it was pressurised?
In general. Pressurisation increases output proportionally if the outside heat transfer area is sufficient until the drag of the working fluid takes over.
by Aviator168
Thu Jan 19, 2017 7:11 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: Trying to make an Andy Ross B20
Replies: 17
Views: 9923

Re: Trying to make an Andy Ross B20

My engine, 30 mm bore, 20 mm stroke is still going strong, about 5 to 10 Watts unpressurized, and unbalanced, with no regenerator. Ian S C That's a respectable output Ian for such an engine. At what rpm do you get that power? If contact area allows, you should be able to 15 - 20 watts per cc with a...
by Aviator168
Fri Jan 13, 2017 7:21 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Stirling engine project help
Replies: 5
Views: 3512

Re: Stirling engine project help

If you are making a portable, you might have to consider the size of the engine and stirling engines are not known for its compactness.