Jump to content

Adding Geyser to PV System


Kalliew
 Share

Recommended Posts

I would like to add the geyser in the flat section of my house to my current solar system (150l geyser - currently on dedicated Eskom circuit).  Geyser is only used once a day for a morning or evening shower.  (The rest of the house is on gas geysers).  I have a 5kw hybrid inverter with 12 panels generating a maximum of 2.5kwh at peak time during the day.  At times, I use the full available pv output at times during the day, e.g. pool pump on, however with effective setting of timers, I have excess power available during the day.

I am thinking of changing the element in the geyser to 1500w (can I go as small as 1000w?).  If I allocate 2 hours in the morning and 2 hours in the afternoon via a DB timer to the geyser, is their any reason why I cannot "go off grid" for the geyser via the solar pv?  Is a 1500w element big enough to reheat the geyser in 2 hours in the morning and 2 hours in the afternoon?  Granted, if I do not have a sunny day, I will still be "on grid" when the geyser timer comes on, however my assumption would be that I can save a fair share of my Eskom spend.

Is their any reason why this cannot be done?  Any pitfalls to look out for?  Any advise will be appreciated.  Thanks

Edited by Kalliew
Link to comment
Share on other sites

12 hours ago, Kalliew said:

I am thinking of changing the element in the geyser to 1500w (can I go as small as 1000w?).  If I allocate 2 hours in the morning and 2 hours in the afternoon via a DB timer to the geyser, is their any reason why I cannot "go off grid" for the geyser via the solar pv?

I think that's marginal - speaking from my own recent experience - though it depends on how hot you want the water to be. You're more likely to succeed if you can give it 4 hours solid.

Whilst you're changing the element, change the anode to extend the life of the geyser.

Link to comment
Share on other sites

I have done the conversion 2 weeks ago and all is working fine.

It can be done nicely with the following.....

 

ecodepot.thumb.JPG.df850f0bd5309753a972c89367fb78aa.JPGtakealot.JPG.3e634738582c2469c98879795896eaf5.JPG

Just make sure you get the right flange for your geyser.

My setup is as follows;

4kW axpert inverter

6*400w Canadian solar panels

4* 100aH batteries that are shot (In the process of getting a 3.5kW Pylon)

The following image is at 11:00 in the morning, but the app switches on the element at 10:00 and off at 13:30, but most times it reaches 65 degrees before 12:00.

I use eskom to top up the heat in the morning and evening, but I think a descent battery would offset the need. 45 degrees in the morning which is perfect for 2 showers and 55 degrees in the evening for doing the dishes etc......

nodered.thumb.JPG.f92469d9c0ad59ebd5bf36bb03108344.JPG

 

The following is my pvoutput.org First for during the week and 2nd for weekend.

week.thumb.JPG.120ca5cdee15f11b6ae114ca8691bcc3.JPGweekend.thumb.JPG.5b6563747ba7c43313a7ad412a838f66.JPG

I still use about max about 10 units a day from eskom, which is about R600.00 a month, for night time use and topping up the geyser.

Hope the info contained here is of some use.

Thank you

 

 

Link to comment
Share on other sites

Warlok - Thank you for posting the shopping list.  I will follow your recommendation to the T.

Still a newb in the solar world.  Please may I ask about your systems app.  Is this a purchased app that communicates with your inverter or is this your inverters app?

image.png.2687e55c1ba8e1f65138ae419eab93a5.png

Does this app auto upload your stats to pvoutput.org?

Thanks

 

 

 

Link to comment
Share on other sites

Hi KallieW

I use solpiplog version 3 on a raspberry pi, installed node red and mqtt.

Connected the Pi to the inverter with a normal usb.

Solpiplog can be found at https://github.com/njfaria/SolPipLog

It was a steep learning curve for me, but once I read all the docs and watched a few youtube videos, I got the hang of it.

I'm adding a few screenshots to get you started.

Or if you want a ready made Pi with ICC software you can go to https://iccsoftware.co.za/icc-pi/

No hard work involved, just plug and play. Just make sure you have a compatible inverter. I have an apert clone and all works fine.

sol1.thumb.JPG.61f8c72aeaf8ce6e766aa2ffd3c3fe4e.JPGsol2.thumb.JPG.e654f8466f1ec5643d0fab33c3e52f33.JPGsol3.thumb.JPG.07cd04bbde29b82a3c105b7cb62182eb.JPGsol4.thumb.JPG.739a7120b19c26cb83e9a18dab831a54.JPGsol5.thumb.JPG.35766da9cdd25fe9754e550817896405.JPGsol6.thumb.JPG.38928b619dde831bb333f95036fdc7dd.JPGsol7.JPG.f98921c9718226860732b0e7cdc2083b.JPG

Link to comment
Share on other sites

Sorry, forgot something. I am busy with a dashboard for the sonoff in node red. You can control the smart switch via the app on your cellphone from anywhere at the same time node red has access to it. It's still a work in progress, so there's a few errors. My aim at the end of the day is to have all the pv data and the geyser temp, power use etc on the dash.

sol8.JPG.37776b08c31b8607749b5cfd283b866e.JPG

Anyway, the switch works perfectly from the cellphone, so no functionality loss so far....

...and the nice thing about is you don't have to flash custom firmware like tasmota, it just works... just have to get the settings right.

Link to comment
Share on other sites

21 hours ago, Warlok said:

I have done the conversion 2 weeks ago and all is working fine.

It can be done nicely with the following.....

 

ecodepot.thumb.JPG.df850f0bd5309753a972c89367fb78aa.JPGtakealot.JPG.3e634738582c2469c98879795896eaf5.JPG

Just make sure you get the right flange for your geyser.

My setup is as follows;

4kW axpert inverter

6*400w Canadian solar panels

4* 100aH batteries that are shot (In the process of getting a 3.5kW Pylon)

The following image is at 11:00 in the morning, but the app switches on the element at 10:00 and off at 13:30, but most times it reaches 65 degrees before 12:00.

I use eskom to top up the heat in the morning and evening, but I think a descent battery would offset the need. 45 degrees in the morning which is perfect for 2 showers and 55 degrees in the evening for doing the dishes etc......

nodered.thumb.JPG.f92469d9c0ad59ebd5bf36bb03108344.JPG

 

The following is my pvoutput.org First for during the week and 2nd for weekend.

week.thumb.JPG.120ca5cdee15f11b6ae114ca8691bcc3.JPGweekend.thumb.JPG.5b6563747ba7c43313a7ad412a838f66.JPG

I still use about max about 10 units a day from eskom, which is about R600.00 a month, for night time use and topping up the geyser.

Hope the info contained here is of some use.

Thank you

 

 

Hi, where did you buy your stuff from?

Link to comment
Share on other sites

On 2021/07/26 at 5:16 PM, Warlok said:

Hi

ecodepot.co.za for the flange, sensor tube and the element.

But make sure you have enough solar for the element. the do come in 1.5kw and 2kw. I still had 55 degrees on my geyser at 17:00 today.

Takealot for the sonoff.

 

 

Thank you for the info, much appreciated. I managed to get all and installed it yesterday. I must say, I'm glad I did this change. the old resistive heating element had some sort of dirt build up on it. I don't know how it still managed to heat the water up, with all that build up. I got the 1.5Kw and using AC for now, but noticed that it is actually drawing 1.9Kw when its ON. 

Link to comment
Share on other sites

On 2021/07/22 at 8:39 PM, Kalliew said:

I would like to add the geyser in the flat section of my house to my current solar system (150l geyser - currently on dedicated Eskom circuit).  Geyser is only used once a day for a morning or evening shower.  (The rest of the house is on gas geysers).  I have a 5kw hybrid inverter with 12 panels generating a maximum of 2.5kwh at peak time during the day.  At times, I use the full available pv output at times during the day, e.g. pool pump on, however with effective setting of timers, I have excess power available during the day.

I am thinking of changing the element in the geyser to 1500w (can I go as small as 1000w?).  If I allocate 2 hours in the morning and 2 hours in the afternoon via a DB timer to the geyser, is their any reason why I cannot "go off grid" for the geyser via the solar pv?  Is a 1500w element big enough to reheat the geyser in 2 hours in the morning and 2 hours in the afternoon?  Granted, if I do not have a sunny day, I will still be "on grid" when the geyser timer comes on, however my assumption would be that I can save a fair share of my Eskom spend.

Is their any reason why this cannot be done?  Any pitfalls to look out for?  Any advise will be appreciated.  Thanks

 

1.5kW for 2 hours is 3kWh of energy you add to the water.

A 150l geyser can lose 1.5-2kWh over a day when including pipes.

A single shower maybe takes 50l of water. To reheat that 50l from say 20C to 60C will take: (60-20) x 50 x 1.16 = 2.33kWh of energy.

 

My guess is that 3 hours will be enough.

You can lower the water temp in the geyser and reduce the heat loss but take into account that say a 50C hw temp might use double the water volume in a shower and 50% more energy to reheat.

Link to comment
Share on other sites

20 hours ago, Kalliew said:

Warlok - Did you use a contactor or did you connect the Sonoff directly to geaser?  Is 16amp enough for the startup surge of the element?  Have seen some posts of the Sonoff "burning".

I connected it directly to the geyser as it only maxes out at 2kw for about 5 seconds and then gradually comes down to 1.5kw. But strangely enough it does not jump to 2kw immediately, but say it takes about 15 seconds for the ramp up to 2kw and to stabelize at 1.5kw (6.5amps) and 2kw, about 8.8-9 amps

Link to comment
Share on other sites

  • 3 weeks later...
On 2021/07/22 at 8:39 PM, Kalliew said:

I would like to add the geyser in the flat section of my house to my current solar system (150l geyser - currently on dedicated Eskom circuit).  Geyser is only used once a day for a morning or evening shower.  (The rest of the house is on gas geysers).  I have a 5kw hybrid inverter with 12 panels generating a maximum of 2.5kwh at peak time during the day.  At times, I use the full available pv output at times during the day, e.g. pool pump on, however with effective setting of timers, I have excess power available during the day.

I am thinking of changing the element in the geyser to 1500w (can I go as small as 1000w?).  If I allocate 2 hours in the morning and 2 hours in the afternoon via a DB timer to the geyser, is their any reason why I cannot "go off grid" for the geyser via the solar pv?  Is a 1500w element big enough to reheat the geyser in 2 hours in the morning and 2 hours in the afternoon?  Granted, if I do not have a sunny day, I will still be "on grid" when the geyser timer comes on, however my assumption would be that I can save a fair share of my Eskom spend.

Is their any reason why this cannot be done?  Any pitfalls to look out for?  Any advise will be appreciated.  Thanks

I've done this for one bathroom in my house that only my son uses.  I've replaced the standard 3kw element with a 2kw element on the 150l kwikot geyser.  I then installed a Geyserwise TSE unit to it to make controlling the temp and timer easier.  I've set the temp to 45 degrees, which he is fine with for his morning shower.  The timer is set from 2PM to 3PM in the afternoon when battery is full.  PV supply's enough power to raise the temp to from 20-25 degrees to around 40 degrees now in winter.  I then set the timer from 7AM to 8AM to top up the temp in the morning before he showers.  The Geyserwise stops the element when temp hits 45 degrees.  It generally runs for about 30 minutes on grid power.  I've just started with this about a week ago and will adjust times as I go.  I'm sure the summer months will be more productive.  BTW, reason I only have it running for 1 hour in the afternoon is that the battery is also used to if the PV is not producing enough. I then have time after 3PM to top the battery up again.

 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...