Loadshedding solutions

[TheoG]

Just now, ouzo said:

Thanks

 

Anything to look out for ? Not do ? Must do ? Stay clear of ?

Not really, just dot it ... .

Just make sure you have 900W on a 150 liter geyser and ~1300W on a 200 liter.

[The Ouzo]

2 minutes ago, TheoG said:

Not really, just dot it ... .

Just make sure you have 900W on a 150 liter geyser and ~1300W on a 200 liter.

its the upfront costs that is the problem. Lets see what SARS gives me back and I'll take it from there.

[TheoG]

Just now, ouzo said:

its the upfront costs that is the problem. Lets see what SARS gives me back and I'll take it from there.

The money honey is always the damn problem ...

I'm in the same boat with Lithium batteries, just out of reach at the moment .

[ChrisF]

14 minutes ago, ouzo said:

Thanks

 

Anything to look out for ? Not do ? Must do ? Stay clear of ?

 

If I had to redo it ....

 

Add 2kW PV panels to the house PV, and use a 2kW element in the geyser.

 

Once the water is hot you have that PV for the house 👍👍

[M L]

1 hour ago, Frosty said:

Guess which two days in the week we have the maid working... washing, ironing, vacuuming, etc.

What a coincidence - my wife also cleans on Mondays and Thursdays.

[The Ouzo]

7 minutes ago, ChrisF said:

 

If I had to redo it ....

 

Add 2kW PV panels to the house PV, and use a 2kW element in the geyser.

 

Once the water is hot you have that PV for the house 👍👍

Has anyone done the calcs of using a 2kw vs a 3kw element in terms of consumption ?

My theory is that the 2kw will run for longer then the 3kw to heat the same amount of water to the same temperature. Therefore the amount of energy used would be the same.

I understand the reasoning of going to the 2kw when you're running off back systems, I'm talking particularly of when it runs off Eskom.

[Steady Spin]

Just now, ouzo said:

Has anyone done the calcs of using a 2kw vs a 3kw element in terms of consumption ?

My theory is that the 2kw will run for longer then the 3kw to heat the same amount of water to the same temperature. Therefore the amount of energy used would be the same.

I understand the reasoning of going to the 2kw when you're running off back systems, I'm talking particularly of when it runs off Eskom.

Same question around turning the temperature of the geyser down. In theory a lower temp = more hot water being used which in turn requires more water to be heated up again...

 

[The Ouzo]

1 minute ago, Steady Spin said:

Same question around turning the temperature of the geyser down. In theory a lower temp = more hot water being used which in turn requires more water to be heated up again...

 

Agreed.

Though to a point. Way to hot and you're wasting energy, so turning it down will help.

[ChrisF]

Geyser elements are typically chosen for a 30 to 45 minute re.heat time.

 

Important for large families that needs re.heating between showers ....

 

If you dont need a fast reheat the 2kW will work fine

 

Use a Geyserwise controller ... let the sun heat the water to 65 degrees by late afternoon.  Set the timer to top up the water temp to 50 or 55 degrees for the morning hot water.

[Frosty]

13 hours ago, Shebeen said:

Those slimline tanks are pricey, if you're going to that effort, sinking a big tank underground could make more sense.  plus you will have soil to make a pump track out of.

I won't consider underground... high water table + clay ground + empty tank (buoyancy problems) = this

[Frosty]

6 minutes ago, ouzo said:

Has anyone done the calcs of using a 2kw vs a 3kw element in terms of consumption ?

My theory is that the 2kw will run for longer then the 3kw to heat the same amount of water to the same temperature. Therefore the amount of energy used would be the same.

I understand the reasoning of going to the 2kw when you're running off back systems, I'm talking particularly of when it runs off Eskom.

Before I replaced my geyser in December, I had a 2kW element. It wasn't for any other reason than to keep the load on the inverter manageable. I now have a 4kW element, and can't replace it or I lose my 5y guarantee/warranty. What that means, is that I can't run my appliances concurrently now, compared to when I had the 2kW element. There is no savings, but rather the ability to multi-task the appliances. 

[Schnavel]

Yup, as mentioned by @Frosty, the main reason for downsizing your element is to avoid overloading of your system. 

Heating water takes the same amount of energy, regardless of what element size you use. The smaller the element, the longer it takes. This can be calculated using the following:

Calculate the kilowatt-hours (kWh) required to heat the water using the following formula: Pt = (4.2 × L × T ) ÷ 3600. Pt is the power used to heat the water, in kWh. L is the number of liters of water that is being heated and T is the difference in temperature from what you started with, listed in degrees Celsius.

As you can see, changing the power of the element, impacts the time taken to heat. In the real world, it would take slightly longer to heat with a smaller element as the standing heat loses are spread over a larger time frame, although, practically, this will likely only result in less than an additional 5 minutes of heating over a 3 hour period.

I run 2 geysers during the day (both 150L). One has a 4kW element and the other a 2kW element. Our household consumption is usually much higher after midday, so I run the 4kW element before 12:00 and then the other element after 12:00. Both geysers are heated using my inverter and solar panels - I just added a few additional panels to account for the additional usage during the day. This was considerably cheaper than converting my existing electric geysers to either gas or solar geysers.

Edited July 19, 2022 by Schnavel

[Schnavel]

Oh, and another very important thing to consider, which is often not done, is to wrap your geyser with a proper blanket. The amount of thermal energy loss is more significant than you think, especially in winter with cold atmospheric temperatures

[TheoG]

Just now, Schnavel said:

Oh, and another very important thing to consider, which is often not done, is to wrap your geyser with a proper blanket. The amount of thermal energy loss is more significant than you think, especially in winter with cold atmospheric temperatures

Done ,,,  

[The Ouzo]

9 minutes ago, Schnavel said:

Yup, as mentioned by @Frosty, the main reason for downsizing your element is to avoid overloading of your system. 

Heating water takes the same amount of energy, regardless of what element size you use. The smaller the element, the longer it takes. This can be calculated using the following:

Calculate the kilowatt-hours (kWh) required to heat the water using the following formula: Pt = (4.2 × L × T ) ÷ 3600. Pt is the power used to heat the water, in kWh. L is the number of liters of water that is being heated and T is the difference in temperature from what you started with, listed in degrees Celsius.

As you can see, changing the power of the element, impacts the time taken to heat. 

Thanks, so my theory is correct then

 

9 minutes ago, Schnavel said:

I just added a few additional panels to account for the additional usage during the day. This was considerably cheaper than converting my existing electric geysers to either gas or solar geysers.

because you already had a Solar setup I assume ?

 

7 minutes ago, Schnavel said:

Oh, and another very important thing to consider, which is often not done, is to wrap your geyser with a proper blanket. The amount of thermal energy loss is more significant than you think, especially in winter with cold atmospheric temperatures

That was done when we insulated the roof.  Geyser also sits directly above the bathroom that we all use, so no heat loss through pipes on the way to the shower.

[Schnavel]

2 minutes ago, ouzo said:

because you already had a Solar setup I assume ?

As I installed my own system when I moved in, I just added additional panels to account for the geyser consumption. The extra 6x panels works out a lot less than a single solar geyser conversion and once the geysers have been heated, I can use the additional PV for other things