Oct 23 2013, 03:57 PM
QUOTE(stevie8 @ Oct 23 2013, 03:02 PM)
With our kind of hot hot hot rain hot hot&rain hot hot&rain weather no problem. Hot&Rain mean rain half day 1-2 hrs hot day is good enough to heat up the whole tank for the day or 2 days use.
My solar heating element ko after few years and did not replace also no problem. Sometime with 3 days continuous rain, on the last day using full hot water still comfortably warm. You just need 1 to 2 hrs of good sun for a day. When it is hot hot days for 3 continuous days the water is super hot. Need just move a little to hot say 1/5 hot 4/5 cold water. Aslso becasue our cold water is already on the high side, ie. 30 degree C, so need no much hot water mixed.
Imagine this:
A good warm shower is 38 degree C (our body temperature is 37 degree). one part hot water 80 degree mix 5 parts cold water at 30 degree (80+30x5)/6 =38.33 degree. It means you need only 1/6 of hot water mix. A 60 gallons hot water means you get 60 x 6 gallon of warm water for shower. Of course there is wastage in the storage losing heat and also cold water in hot pipe between showers.
Is my calculation correct?
A good hot water shower is 42 degree C. Still you get plenty. you do the calculation.
My solar heating element ko after few years and did not replace also no problem. Sometime with 3 days continuous rain, on the last day using full hot water still comfortably warm. You just need 1 to 2 hrs of good sun for a day. When it is hot hot days for 3 continuous days the water is super hot. Need just move a little to hot say 1/5 hot 4/5 cold water. Aslso becasue our cold water is already on the high side, ie. 30 degree C, so need no much hot water mixed.
Imagine this:
A good warm shower is 38 degree C (our body temperature is 37 degree). one part hot water 80 degree mix 5 parts cold water at 30 degree (80+30x5)/6 =38.33 degree. It means you need only 1/6 of hot water mix. A 60 gallons hot water means you get 60 x 6 gallon of warm water for shower. Of course there is wastage in the storage losing heat and also cold water in hot pipe between showers.
Is my calculation correct?
A good hot water shower is 42 degree C. Still you get plenty. you do the calculation.
QUOTE
Sorry, There are mistakes in the assumption and calculation. I re-calculate using different method. Assuming 90 degree C hot water in the tank, it is 1/4 hot and 3/4 cold to achieve a 37.5 degree warm water shower. Anyway, in real world (not mathematics calculation), the heater continues getting heating up by the sun as you use during the day giving you endless supply and also the next morning it continues...Therefore, the above calculation applies to continuous raining/no sun days and night use.
stevie
*kowtow* subject to the pipe costing, u may just make me switch camp 
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