AgTalk Home
AgTalk Home
Search Forums | Classifieds (109) | Skins | Language
You are logged in as a guest. ( logon | register )

Idling/starting throughout day in cold
View previous thread :: View next thread
   Forums List -> Kitchen TableMessage format
 
ksfarmboy1960
Posted 2/4/2019 20:14 (#7297251 - in reply to #7292954)
Subject: RE: Idling/starting throughout day in cold


NE Kansas
THERMODYNAMICS # !
I takes ( 1 ) BTU/lb of water to raise or lower the temperature of the water 1 degree F

It takes 144 btu/lb of water to change 1 lb of 32 degree water to 1 lb of ice ( this is called Latent heat of fusion )

It takes 1744 btu/lb of 212 degree water at sea level to 212 degree steam. ( this is called Latent heat of fusion )

HEAT flows from Hot to Cold

Heat loss/Heat gain formula = Area X TD ( temperature ) x Conduction factor = heat loss or gain

Single pane glass conduction rate is approx. 1.1 Double pane is .55 (Ex.) Heat = 10 Sq.ft of glass x Cond.factor 1.1 x 0* outdoor temp. 70* indoors Equals 10 x 1.1 x 70 = 770 btu /hour heat loss

So as the 100* and 60* water in the above example approaches the 40* temperature the conduction rate slows down ( temperature difference approaches 0 ) Remember 60-40 = 20 td ,100-40 = 60 td therefore both the 100* and 60* will eventually reach 40* ( 0 TD ) Then heat exchange ceases.

Also a term ( Coefficient of heat ) Water is the base Water = 1 Lead and heaver material has higher coefficient Basically it is how much heat a different material will hold for the same weight Ex. Water verses lead or steel, rocks etc.
Hot water will not freeze faster than cold water if put in seperate identicle containers based on the 1 btu/lb per degree temperature difference

Not trying to be a smart ass ,just stating laws of thermo Dyn.

Hope this helps


Edited by ksfarmboy1960 2/5/2019 14:17
Top of the page Bottom of the page


Jump to forum :
Search this forum
Printer friendly version
E-mail a link to this thread

(Delete all cookies set by this site)