Mathew, There are three issues here: 1. Antifreeze is not as good a conductor of heat as water so in that respect it is not so good BUT 2. Antifreeze (in very simple terms) suppresses the water (pool boiling) boundary layer next to a metal surface that reduces heat transfer so thus improves heat transfer AND 3. Antifreeze prevents the formation of the crud seen on hot surfaces, which is a carbonate precipitated from the water. This carbonate has a low thermal conductivity so as the crud thickness increases so the metal surface will become higher for a given water temperature the other side of the crud. It is the suppression of the crud effect that actually gives the greatest advantage so if not using antifreeze then some other carbonate suppressor should be used - an example measured when I was working was that 1 mm of carbonate deposit on a valve bridge increased the metal temperature by 600° C. It is not unusual to find deposit layers of up to 5 mm on old engines that have been run with no carbonate suppressor - the mind boggles on the metal temperatures that might be achieved. The best policy is to never let the carbonate form from new so always run with 50:50 antifreeze:water.
If you require greater detail then I could ask my son, who is a specialist in this field. Hamish ----- Original Message ----- From: Matthew To: [email protected] Sent: Saturday, April 18, 2009 9:10 AM Subject: [Quantum Owners] Antifreeze - thermal transfer? Hello, I got involved in an interesting discussion last night*. "Does anti-freeze increase thermal transfer" The popular opinion appeared to be yes, but it seems to turn out that this is not true. Granted it increases boiling point and decreases freezing point. However it would appear that it is actually not as good at transferring heat as water. Does anyone know the actual answer (and can prove it)? Matthew *yes wild party nights around here! --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Quantum Owners Group" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/quantumowners?hl=en IMPORTANT NOTE: All information presented herewith is provided on an "As Is" basis, without warranty or the implication thereof. Neither the Quantum Owners Club nor the individuals associated with the Quantum Owners Club or in the preparation of the above information shall have any liability to any person or entity with respect to liability, loss, or damage caused or alleged to be caused directly or indirectly by the instructions contained within this or related message(s). -~----------~----~----~----~------~----~------~--~--- ------------------------------------------------------------------------------ Internal Virus Database is out of date. Checked by AVG - http://www.avg.com Version: 8.0.176 / Virus Database: 270.10.23/1951 - Release Date: 13/02/2009 06:51
Internal Virus Database is out of date. Checked by AVG - http://www.avg.com Version: 8.0.176 / Virus Database: 270.10.23/1951 - Release Date: 13/02/2009 06:51
