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Clean Slate - Now what???


TheoG
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Hey guys.

So my previous setup was a 150lt geyser and 5.5kw heatpump.

The geyser is on it's way out and the heatpump trips the earth leakage every now and then (but not consistently... Any thoughts?). I believe this could be fixed (hopefully).

So i have about R30k available to spend.

 

I initially thought to go solar geyser (200lt Kwikot) on the roof but after reading through the post on the forum I'm thinking that might not be the best option.

I have 8 x 200ah batteries ready to be connected. Was holding off for a good deal on an inverter and hopefully some panels to get started on the solar side.

 

We shower at night and do not require hot water in the mornings as we have a gas geyser in the kitchen.

 

My options are :

1. Solar geyser (R28k local quote)

2. Geyserwise dc/ac conversion on new 200lt geyser (R20k + new 200lt geyser)

3. Spend the R30k or maybe a bit more on a grid tied system and just install a 200lt geyser and have it run off the inverter? I do have 8 x 200ah batteries waiting to be connected to a hybrid maybe?

 

Any suggestions or other options to consider?

 

Thanks in advance!

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3 minutes ago, TheoG said:

Hey guys.

So my previous setup was a 150lt geyser and 5.5kw heatpump.

The geyser is on it's way out and the heatpump trips the earth leakage every now and then (but not consistently... Any thoughts?). I believe this could be fixed (hopefully).

There is no need to feed the heatpump via the E/L. As long as it and the geyser are properly earthed you are fine. (There aren't any earth leakages installed in industrial plants due to their oversensitive behavior) 

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8 minutes ago, TheoG said:

My options are :

1. Solar geyser (R28k local quote)

2. Geyserwise dc/ac conversion on new 200lt geyser (R20k + new 200lt geyser)

3. Spend the R30k or maybe a bit more on a grid tied system and just install a 200lt geyser and have it run off the inverter? I do have 8 x 200ah batteries waiting to be connected to a hybrid maybe?

I planned on getting a Geyserwise dual system as well but thought one large integrated system might be better. But now I'm changing my mind back to my first choice. The reason is the all the hoops we have to jump through feeding/not feeding back into the grid. Better perhaps to dedicate a couple f panels to sorting out your hot water and no fancy hoops to jump through.. 

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8 minutes ago, Bloubul7 said:

I would go with Option 3.  I'm currently running 2 geysers of my inverter.  The geysers are on smart thermostats to ensure that they only heat up during the day with a second cycle should it drop below a specified temperature.

Could you elaborate on the smart thermostats?

 

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1 minute ago, TheoG said:

Could you elaborate on the smart thermostats?

 

It is basically a Sonoff TH16 switch with a relay and a DS18B20 temperature sensor.  The Sonoff TH16 communicates to a Home Automation server, within the automation server one can set up rules and timers for when the relays are to be switched on.

 

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On 2020/10/08 at 3:36 PM, TheoG said:

So my previous setup was a 150lt geyser and 5.5kw heatpump.

I would go for option 1. Solar geyser, but a 200Ltr  EV tube unit and would also get that heat pump fixed for backup on rainy days.

I am happy with my own EV tube geyser and cannot complain, winter days it normally does go above 50degrees and  summer it’s a bit over hot, yesterday it went to 84Degrees. 

But than the R28K is allot to spend I would get more quotes.

 

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2 hours ago, Solaris said:

I would agree with these suggestions given. If I had R30k I would definitely spend it on more PV than waste it on a solar geyser. A solar geyser only heats the water, it has no further use. Solar panels and an inverter produce power that can be used for anything.... 

Sure! But this isn't as easy as it might seem. Check this thread for more on this: 

 

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8 hours ago, Richard Mackay said:

But this isn't as easy as it might seem

Haha,  I beg to differ.. It is very simple. SWAMBO is home all day long she turns the geyser on when the batteries are full and turns it off if they are too low. No need for complicated electronics... 🤣🤣🤣🤣🤣🤣

On a more serious note, if you have a big enough PV system you can leave the geyser on permanently. 

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  • 3 weeks later...
On 2020/10/10 at 9:55 AM, Solaris said:

If I had R30k I would definitely spend it on more PV than waste it on a solar geyser.

Adding more PV to an existing inverter could be a solution but what should someone do that have no inverter and no PV. I am also thinking what the best solution is. Say you have a property that you rent out and it’s time to replace the geyser, would PV be the better option than a solar geyser also looking  at dense lower cost housing units I see much more solar geysers than PV panels. Do the architects prefer solar geysers due to lower cost or is their other benefits compared to PV?

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11 hours ago, Gerrie said:Say you have a property that you rent out and it’s time to replace the geyser, would PV be the better option than a solar geyser also looking  at dense lower cost housing units

This would change the equation slightly in my opinion. If I owned a house and rented it out, I would rather add an EV geyser because a tenant might not take the time to look after my expensive PV system. For example, my PV system is used only by my family and we all know how much it can handle. We cannot have the oven, tumble dryer, kettle, dishwasher and hairdryer on at the same time. We have to stagger our loads and use different appliances at different times of the day. Also we need to manually change over to Eksdom when the batteries get to a certain SOC (This is an off grid system) The tenant will not do this. 

When it comes to low cost housing there is another consideration. The roof would have to be very big to accommodate the many panels needed for charging a battery bank big enough to power a geyser. There just isn’t enough real-estate to mount all those panels. Here an EV geyser would be better as it is small and efficient. 

Something else that is very seldom considered has to do with the weight of the EV geyser. A friend of mine who works for a company that makes roof trusses says that the roof needs to be reinforced to carry the weight of the 200 kg to 300+ kg geyser. After some time the roof will start to sag if the job is not done properly. I don’t build roof trusses, but this makes sense to me. 

 

Many variables to consider... 

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On 2020/10/10 at 8:34 PM, Solaris said:

Haha,  I beg to differ.. It is very simple. SWAMBO is home all day long she turns the geyser on when the batteries are full and turns it off if they are too low. No need for complicated electronics... 🤣🤣🤣🤣🤣🤣

On a more serious note, if you have a big enough PV system you can leave the geyser on permanently. 

I have two geysers with timers on a hybrid inverter system.  Our power usage curves are fairly constant so the timers work fine to get most of the energy from the sun.  When the batteries are too low is just draws 1/3rd from the grid and 2/3rds from the solar panels.  Win win. But a hybrid inverter alone cost about R30k.  Would love to have a heat pump for lower power usage.  

Two geysers in series and the first one is going to get a cheap R4k flat plate collector to reduce energy usage.  Second one remain electrical and on pv power.

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9 hours ago, Solaris said:

I would rather add an EV geyser because a tenant might not take the time to look after my expensive PV system.

I agree people who pay for their own systems will tend adhere to the limits and good practice of a system but most tenants will not be interested in the do’s and don’ts of solar.

 

10 hours ago, Solaris said:

The roof would have to be very big to accommodate the many panels needed for charging a battery bank big enough to power a geyser.

My own home also have limited roof  space for panels so more PV panels just for the geyser would be a bit challenging. 

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17 hours ago, Gerrie said:

My own home also have limited roof  space for panels

Is this roof east/west or north/south facing? Lots of people have found the east/west setup better for more production throughout the day. 
Other people have filled the north roof with panels and then made special brackets to attach more panels to walls on one or both sides. I was also toying with the idea of building a porch off of my lounge and using panels to make the roof.

In your case it might just be easier to go EV geyser as it takes up little space compared to it’s PV generating equivalent. 

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18 hours ago, Solaris said:

Is this roof east/west or north/south facing?

The roof has four sections facing in all four directions, N,E,S,W but on North and South sides it is smaller than East & West sides. North and South sides would probably only take about six to eight 330W panels as where East and West sides could each take about 12 panels. I guess a inverter with two Mppt’s might be ok for different facing arrays. 

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19 hours ago, Solaris said:

Lots of people have found the east/west setup better for more production throughout the day.

Be VERY careful about East-West panels.  See this post 

 

Bottom line: East/West panels add a little bit in summer early morning and late afternoon.  In winter they are a disaster.

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1 hour ago, Calvin said:

Be VERY careful about East-West panels.  See this post 

I totally agree that there will definitely be a loss in production. However, no matter the time or season an east/west array used to SUPPLEMENT your north array is always well worth it. Even if this east/west array only produces 40% of what it is rated for, that is going to help you overall production. 

 

1 hour ago, Calvin said:

In winter they are a disaster

I wouldn’t quite describe it as a disaster. 😁 There is a big drop in production, but as stated above, this is a good addition to your existing north array. 

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2 hours ago, Gerrie said:

I guess a inverter with two Mppt’s might be ok for different facing arrays.

Not necessarily. I learned from Phil.g00 who is a member here that you can put multiple strings, and at different orientations on one MPPT. Check topic posted below. I tried this myself and was quite surprised by the results. I am currently using one MPPT for both east and west arrays. 
 

 

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16 minutes ago, Solaris said:

However, no matter the time or season an east/west array used to SUPPLEMENT your north array is always well worth it. Even if this east/west array only produces 40% of what it is rated for, that is going to help you overall production.

Clearly ANY panels will aid in overall production (unless you put them upside down 😁).

However, saying "it is always worth it" to but in extra panels "even if they produce only 40% of rated" misses the fact that for most people the installation of PV systems is marginal even when using optimal panel positions.

30 minutes ago, Solaris said:

I wouldn’t quite describe it as a disaster. 😁

Fair enough - bad choice of word.  We all have different ideas of what constitutes a disaster.

I guess that what I am trying to say is: if you can place your panels facing North, absolutely do so.  If you don't have the option by all means place them East/West, but be aware of the reduced yields, especially in winter.

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