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Size of Geyser


Chris Hobson
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Hi Everybody

 

Today I got a Jacob Zuma windfall in the form of a wool cheque. Up until now we have used gas for water heating.  I am planning to buy a standard geyser and power it with excess energy from the solar panels. What size geyser for a family of three? We only have baths unfortunately quite  big ones. The one bath is 1.6 long by 650mm wide by 520 mm deep (looks a bit like a diptank probably uses 250l of water). The other is a bit smaller.

 

What size geyser? I was thinking a 250l geyser would give us two baths covering the time we don't have guests and then we would heating extra water when we have guests with the gas geyser. A bath with my son in it is about 41oC and 100l and my wife and mine is a bit hotter and fuller.

 

Chris

 

Edit: It looks like I will only have enough energy for a 150-200l geyser.

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Rule of thumb: 50 liters per person plus 50 for dishes. So 200 liters. But that's obviously too small if you need to supply a Roman bath house with hot water.

 

Energy needed: 1.16Wh to heat one liter of water by one degree kelvin/centigrade. So around 9-10kwh for 200 liters (assuming a delta-T of 40 degrees).

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I have a 200l for 4 people, on EV tubes.

 

If I do it again, I will go for 400l on EV tubes.

 

200l is used up way to fast, 400l will keep longer and to heat it up with solar, not a problem. 

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Rule of thumb: 50 liters per person plus 50 for dishes. So 200 liters. But that's obviously too small if you need to supply a Roman bath house with hot water.

 

 LOL my wife has tears in her eyes from laughter!

 

Energy needed: 1.16Wh to heat one liter of water by one degree kelvin/centigrade. So around 9-10kwh for 200 liters (assuming a delta-T of 40 degrees).

It looks like it will be a 200l geyser as I have about 10 kWh spare capacity. If I need to expand I will add a 150l which is being modified to accept more than oneelement for my hare-brained schemes.
 
Thanks
Chris
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Returned with a 200l geyser and a 1.5kW element with a pocket. Could get a 1kW element but without a pocket. Today was 42oC so we will not be rushing to install the geyser. Although the geyser will be outside the cabling will have to go through the loft and the loft is like an oven even on a mildly warm day.

 

Edit: Temp was about 42oC in the shade but look at this.

 

post-822-0-27415300-1450503169_thumb.jpg

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Returned with a 200l geyser and a 1.5kW element with a pocket. Could get a 1kW element but without a pocket. Today was 42oC so we will not be rushing to install the geyser. Although the geyser will be outside the cabling will have to go through the loft and the loft is like an oven even on a mildly warm day.

Can you give brand and prices on this please Chris

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Can you give brand and prices on this please Chris

 

Hi Viper

 

It is a Kwikot Ecoline without a collector but with pressure release and vacuum breakers. The price was R3800 and some change (ex VAT). It was supplied by J&B Boerediens an unique business that supplies farmers with their needs. It carries very little stock but because of volumes is able to negotiate trade prices and passes most of the saving on to the farmer. With a long list of supplies to get I did not have the time to shop around but the price seemed competitive. I arrived just before they closed for Xmas so left without any paperwork.

 

The elements were 121.68 each and thermostats 203.23 each supplied by TecsaReco. I live too far from suppliers for me to be able to wait for couriers etc so where possible I carry my own spares. 

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How would one supply the 12V DC directly from your batteries?

nope direct from the panels, i think they supply 12v - 48vdc elements.....

Energi Mart AC/DC System

Energi Mart manufactures and supplies the AC/DC element kit that can be retrofit to any existing or new geyser installation. Just add solar according to our installation guide and you are ready to start using PV to power your life.

System components: 

1 x AC/DC element combo

1 x AC thermostat

1 x DC thermostat

1 x DB timer

1 x Flange & Rubber (flanged type geysers)

Untitled-2-93x300.png  Dc-Thermo-144x300.png AC-Thermo-158x300.png  Timer-133x300.png

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Kwikot is known to last 1 day before / after warranties. Reason why Kwikot is so huge? They sort problems quick.

 

Having said that, after a 3rd geyser burst in the roof in 15 years, with the resultant mess, I am now on a Duratherm geyser, outside the house.

 

Insurance paid out the cash, I added a few rands, and now have a 10 year warranty and when the geyser does burst again, it is outside.

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Mike - Do you have an indication of price on the Energi Mart AC/DC System? (Ex the panels)

 

I just moved into a new house and are looking into heating the geyser with solar (Either PV or Tubes)

 

I have a 250l geyser that is going to be used by 2 people (that might increase in future). So looking for something that can be upgraded later on (No need for a 24 tube system at the moment)

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Hi Chris & Louw,

 

sorry for the  late response. Chris they sell a combo element, not sure about the hard water element, Louw the last time i got from them it was around R2900excl of VAT. I don't think they will sell direct, so if you need let me know. if you not in Cape Town then courier costs as well

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  • 1 month later...

post-822-0-19999800-1453619742_thumb.jpg

 

I have had a stainless steel flange plate made with two ports for standard elements. I will now be able to power it via solar and power it using 2 phases when the generator is running (1 via the inverter). I have not finished the job but just wanted to see whether it fitted as the engineering works did not listen to my instructions carefully. 

 

Anyway this is the next step in my hare-brained scheme.

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WELL DONE Chris !!!

 

Sorry ... but I HAVE TO, cannot help myself (ROFL) : Did you re-use the bath water, filled to the brim, on the garden or in the toilets?  :D  :D  :D

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The bath water waters some arum lilies and a Camdeboo stinkwood. :) .

 

The geyser is plumbed so that it can either use rainwater or borehole water. At the moment it is using borehole water. I have a couple of leaks to solve and then I will switch over to rainwater. Gas geysers have fewer hassles on rainwater. We will see if this holds true for electric geysers. 

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This evening I have run the first of many hot baths powered by excess energy from my PV array. To celebrate it was brim full.

Big win... well done.!!!

 

I am as far as moving my geyser to the roof next to the low pressure solar and using a 12V ITS reticulation pump circulating the water.  Its wired to the DB on Eksdom but set to 55deg.  Solar heats the water and AC keeps it above the 55deg threshold.  Plan to go with your solution when I have a lot more panels. 

 

Enjoy

Sent from my SM-P605 using Tapatalk

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