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solar geysers power


maxomill
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I have a 300l solar geyser that im not impressed with

I was expecting at least 55 degrees in summer

it  has 3 flat plate collectors  and I have barely seen it get over 50 degrees  even in summer so I seem to use a lot of Eskom

 can anyone explain  what amount of power it would take to lift the temp of 300l by say 20 degrees as maybe I'm shooting this thing down    without seeing all the facts

cheers maxomill

 

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I have 2 flat plate collectors on a 200L geyser and it is great (only 2 people in the home though), I get 50' in mid winter and 75' in mid summer - maybe it is something else in your installation that is at fault. Is it thermo-syphon, direct, or indirect (glycol)?

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Hi Maxomill use this.        Q=mc (T1-T2) /3600 .   Q = Energy Kwh needed to raise water temp from T1 to T2. . m =  mass of water . 300 kg  c= specific heat of water  (4.19 kj / kg/ C)

 300 lt  with 3 Kw element  heat 9 degrees C per hour . Without any sun

We have  a 100 lt geyser  with 1 plate collecter ( 2 .2 ) and on very hot days have to releas some hot water 78 degrees . Sunny winterday  50 -56 degrees.

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38 minutes ago, Chris Louw said:

Hi Maxomill use this.        Q=mc (T1-T2) /3600 .   Q = Energy Kwh needed to raise water temp from T1 to T2. . m =  mass of water . 300 kg  c= specific heat of water  (4.19 kj / kg/ C)

Slightly simpler... 1.16Wh per liter per degree centigrade. You can derive it from basics if you want to, but I find this is a little easier to remember.

So lifting 300 liters of water by 20 degrees: 300 * 20 * 1.16 ~= 7kwh.

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thank you all  .

its a high pressure system with a thermo siphon jacket around the cylinder.

this is my issue  7 kw  to lift 20 degrees means its doing its thing and seemingly quite well

but then why am I the only person complaining that my water is not hot enough

btw I even tried a circulation pump to rule out a air lock in the heating system , no change .

seems like it is what it is for me , maybe just a bad design  bad angle

cheers all

 

 

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