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Posted By: CleanEnergiesSHC changes depending on the temperature of the water also, so I always presumed it was because the weight could remain a constant, whereas the volume was a variable?
Posted By: CleanEnergiesI see what you are saying Ed Davies, and am aware of the facts you outlined above albeit not in as much detail as you have provided." alt="" src="http:///forum114/extensions/Vanillacons/smilies/standard/bigsmile.gif" >When I said; 'so I always presumed it was because the weight COULD remain a constant' I was implying and presuming as stated, that if we are talking about a mass of water in a vessel (sealed for e.g) as the temperature rises the volume will increase (taken up by expansion vessel for example) whereas the weight would remain the same (weight decreases but volume increases?) so a kg of water would be greater than 1 litre but the overall weight of the mass in question (within the sealed vessel) would remain the same?Or am I wrong (and perfectly happy to accept that) and the mass in question would physically weigh less than the same mass at a lower temperature in such test conditions?I am interested to hear the answer as you say, normally you have to apply some kind of benchmark to work off, particularly in my line of work were the effects are negligible in reality.Thanks, Sam
Posted By: Ed DaviesAs we warm it (above 4°C) it expands (volume increases and density decreases) and some of it flows out into the expansion vessel. If we consider the water that's flowed out to still be in the game then we're thinking about a fixed mass.
Posted By: CWattersWater is strange stuff..http://www.lsbu.ac.uk/water/explan4.html" >http://www.lsbu.ac.uk/water/explan4.html
Posted By: JSHarrisPosted By: CWattersIs the specific heat capacity of the water greater at the bottom or the top of my thermal store :-)And does it really matter?Given the wide variation in heating demand we have to deal with, due to factors like unusually warm or cold seasons, there's no merit in getting overly precise with heating or energy storage calculations . I'd argue that getting within 10% is plenty good enough for thermal storage calculations.
Posted By: CWattersIs the specific heat capacity of the water greater at the bottom or the top of my thermal store :-)
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