which end is the cold end

[aiad7]

Hi and best regards to you all,

when using stirling engine, alpha type, as a fridge, i.e using a motor to run stirling engine.

how to know, which end of stirling engine is the cold end, without touching the engine

or using thermometer?. is there any rules for that?.

Thank you.

aiad7

[Ian S C]

When the motor is turned by another motor in the same direction as it normally runs as a motor, the hot end will become cold. If you look on my gallery you will see my Ross Yoke motor, when it was driven by another stirling engine at about 700 rpm, the temperature dropped to -20*C from an ambient temp of 18*C in around 10 min. The top of the hot end gets a coating of frost, so you can see the effect of the cooling. You have to have reasonable cooling at the cold end, because it heats up, it's just like an air conditioning unit, or a frig. Ian S C

[aiad7]

Hi and best regards to you all,

Ian, thank you very much indeed.

aiad7.

[sequesteredsun]

Hi Ian ,
I am interested in what actually is going on when this scenario of cooling is in play.
I understand the air in your engine is being compressed ,thus heated, then the pressure drops when the power piston draws out of the cylinder , thus cooling, is the cold end and the hot end in the cooling situation determined by where the displacer is during compression /expansion ? Is my understanding correct or is there more going on that I do not realize?
Thanks Seqsun

[Ian S C]

Seqsun,the motor is actually just doing the same as it always does, the displacer is removing heat from the hot end (it does this when it's running as a motor), and giving it up at the cold end. There is always heat, even when the temperature gets to near Absolute Zero ie -273* Kelvin, actually if the driving motor stopped for some reason, the Stirling engine would try to run backwards, until the temperatures equalise. Ian S C

[sequesteredsun]

Hi Ian , I understand that aspect, but is there something going on with compression and expansion via the power piston?
Seqsun