Sorry 137 KWh a day is the correct value. -----Ursprungligt meddelande----- Fr=E5n: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU]F=F6r Ake Hedman Skickat: den 6 april 2004 11:02 Till: PICLIST@MITVMA.MIT.EDU =C4mne: SV: SV: ] Superb low temperature differential Stirling Engine But if you use a higher temp difference. In my case I warm the house with pellets and say I have a stirling engine in a pre stage to my heater. pellets burn with a temp around 1200 C 1200 + 273 - 300 / 1475 =3D 79% 1/3 =3D> 27% This goes to the electric generator. I guess the losses are in heat so it can be used it to warm the house. I use about 1000 kg of pellets a week for warming in the winter ( big house ). The total energy used a day is thus 1000 * 4.8kWh =3D 4800 KWh Say I have 20% efficiency for the electivity generator I can take out 960 KWh a day in electric energy!!! and have the rest left to warm the house. Do I have a fault in my thinking here? /Ake -----Ursprungligt meddelande----- Fr=E5n: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU]F=F6r Russell McMahon Skickat: den 6 april 2004 09:26 Till: PICLIST@MITVMA.MIT.EDU =C4mne: Re: SV: ] Superb low temperature differential Stirling Engine This has always fascinating me. > Living in Northern Sweden with with the heater on for the bigger part of > the year: Could a stirling engine be used to drive an electric > generator? Anyone tried that? Short answer: No. Conservation of energy applies. You need an energy source to power the motor and all such motors will result in an overall net energy loss. However, if you had a low grade source of heat you could conceivably use it to drive an engine to do useful work. You could eg use a Stirling that ran off the difference between ceiling and floor heat to drive a fan to pump hot air down to floor level. Would run faster as difference increased :-) A Stirling engine's MAXIMUM THEORETICAL efficiency is (Tin-Tout)/Tin. T in degrees Kelvin =3D C + 273 actual efficiency is typically 1/2 to 1/3 of this although theoretical can be approached more closely in a good design. eg Boiling water in and room temp out =3D 373 K in and 300 K out. Eff =3D (373-300)/373 =3D 19.6% MAXIMUM. Actual would be typically 5% to 10%. Which shows why a HOT Tin is desirable. A Stirling runs on the Carnot Cycle which is the most efficient cycle possible BUT a good engine on another cycle can be more efficient than a bad Stirling Engine. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads