Chris Hobson Posted December 17, 2015 Share Posted December 17, 2015 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. Quote Link to comment Share on other sites More sharing options...
___ Posted December 17, 2015 Share Posted December 17, 2015 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). Chris Hobson 1 Quote Link to comment Share on other sites More sharing options...
Guest Posted December 17, 2015 Share Posted December 17, 2015 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. Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted December 17, 2015 Author Share Posted December 17, 2015 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 Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted December 17, 2015 Author Share Posted December 17, 2015 Thank-you TTT and Plonky for the help. Quote Link to comment Share on other sites More sharing options...
Energy-Jason Posted December 18, 2015 Share Posted December 18, 2015 Pic attached viper_za, ___ and Chris Hobson 3 Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted December 18, 2015 Author Share Posted December 18, 2015 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. Quote Link to comment Share on other sites More sharing options...
viper_za Posted December 18, 2015 Share Posted December 18, 2015 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 Quote Link to comment Share on other sites More sharing options...
Mike Posted December 19, 2015 Share Posted December 19, 2015 you guys do know about the 12vdc/ 220vac element out there that you can retrofit and have the best of both, one supply has one where no mppt is required and the other with mppt. Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted December 19, 2015 Author Share Posted December 19, 2015 you guys do know about the 12vdc/ 220vac element out there that you can retrofit and have the best of both, one supply has one where no mppt is required and the other with mppt. How would one supply the 12V DC directly from your batteries? Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted December 19, 2015 Author Share Posted December 19, 2015 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. Quote Link to comment Share on other sites More sharing options...
Mike Posted December 19, 2015 Share Posted December 19, 2015 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 SystemEnergi 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) Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted December 22, 2015 Author Share Posted December 22, 2015 Hi Mike I have hit a snag. I did not realise that Kwikot was a flange type geyser. What wattage do the AC/DC elements come in? Do they have hard water elements? Does the flange have a port for a standard geyser element? Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted December 22, 2015 Author Share Posted December 22, 2015 Hi Jaco Thanks for the heads up. It is supposed to have a 3 year warranty and we will see. I am mounting it outside where a previous archaic (1970s) solar geyser stood so hopefully if it bursts it it will not do too much damage. Chris Quote Link to comment Share on other sites More sharing options...
Guest Posted December 22, 2015 Share Posted December 22, 2015 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. Quote Link to comment Share on other sites More sharing options...
Louw Posted December 23, 2015 Share Posted December 23, 2015 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) Quote Link to comment Share on other sites More sharing options...
Mike Posted December 23, 2015 Share Posted December 23, 2015 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 Chris Hobson 1 Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted January 24, 2016 Author Share Posted January 24, 2016 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. Quote Link to comment Share on other sites More sharing options...
Mark Posted January 24, 2016 Share Posted January 24, 2016 Looks good... great idea. Looking a bit dry at the back there... hope you got some rain yesterday and last night... We had a surprise 47mm in 3hrs early AM @aloeridge . Very happy!! Cheers M Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted January 26, 2016 Author Share Posted January 26, 2016 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. ___ and Mark 2 Quote Link to comment Share on other sites More sharing options...
Guest Posted January 26, 2016 Share Posted January 26, 2016 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? Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted January 26, 2016 Author Share Posted January 26, 2016 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. superdiy 1 Quote Link to comment Share on other sites More sharing options...
___ Posted January 26, 2016 Share Posted January 26, 2016 TTT, you clearly live in Cape Town... :-) (As do I... for that matter :-) ) Quote Link to comment Share on other sites More sharing options...
Guest Posted January 26, 2016 Share Posted January 26, 2016 Where else can one live as good as one can in Cape Town? Ok ok ok ... the Karoo is as good as Cape Town. Quote Link to comment Share on other sites More sharing options...
Mark Posted January 27, 2016 Share Posted January 27, 2016 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 Quote Link to comment Share on other sites More sharing options...
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