DC Geyser Element

[pietpetoors]

I saw this the other day and think it is a great idea.
I am planning on installing one at my home and then if it works sell it in my shop.

You can get the element in DC only or in combination of DC and AC
From 1500watt to 3000watt

The nice about AC/DC is you put your normal 220 volt on timer to only work at night (mine already does)
and you put the DC directly on 3x 240watt solar panels.

They are available in 24-36V and also 48-72V

What I like about this instead of a hot water solar system is that you can use the same panels to generate power for other things.

Just not sure if you have to run some panels in parallel to get to 36 volt, how do you then connect your batteries?

3x panels plus the element should cost about R8k (2200 watt element) which is less than some solar heater systems out there. You use the existing geyser.

O ja and the specific model I am looking at uses a Titanium element.
Apparently it does not build up scale and have a life expectancy of 10 years.

I saw somewhere that a 1mm build up of scale can reduce the efficiency of an element by 18%.

Oh ja and on a last note, maybe one can even use a small DC element to heat the water for your bush shower?

Geyser element

geyser-element.jpg (10.14 KiB) Viewed 19916 times

[JamesC]

I would be very interested in this since I install solar geysers. Problem I see with your pic is that it is a flange type element which fits only some lesser quality geysers on the market. Do they have a screw in DC element?

[pietpetoors]

flange type element which fits only some lesser quality geysers on the market

Oh, I always thought Kwikot and Franke were some of the better quality?
I have a new Kwikot and it has a flange type?

What is a good make then?

They have the screw in type.
See
http://www.nu-inc.co.za/nuthermo/nuther ... -elements/" onclick="window.open(this.href);return false;

[CasKru]

flange type element which fits only some lesser quality geysers on the market

Oh, I always thought Kwikot and Franke were some of the better quality?
I have a new Kwikot and it has a flange type?

What is a good make then?

They have the screw in type.
See
http://www.nu-inc.co.za/nuthermo/nuther ... -elements/" onclick="window.open(this.href);return false;

Pieter... ek dink James vra of jy ie skroef tipe kan kry want volgens die prentjie is dit nie 'n skroef tipe soos Kwikot vat nie

[JamesC]

Franke and Gap is crap

[JamesC]

Piet, the sum does ot work and this seems to be once again a marketing thing in order to sell something.

There are guys on the forum that know way more than me but I can tell you the following for a fact:

1. In order to heat up 150L you will need at least 7.5-8kw/day. A 1000W worth of panels, might, on a GOOD day, give you 5KW.
2. You need at least 9-10kw/day to heat up 200L.

It seems to me they are selling them pre-packaged in order to be competitive against solar geysers.
With 3x240W panels you are not even ballpark and if you get that 150 to 45 degrees with DC, consider yourself lucky. AC will do the rest.

[pietpetoors]

Ah thanks, that is why I asked here before I spent the money.

See I thought it will use 2 hours to heat the 150 litres and the rest of the day it can charge batteries.

[JamesC]

Nope...that will not do.

However, just getting prices from them now.

If you look at this one 2200W ACDC – R1 800 + VAT - available in 24-36V and also 48-72V and add 1500W on the roof at R11/watt you are on
R16500 + 1800 + VAT = 20,862 which puts you in the price range of a fairly high quality solar geyser.

Made a few quick calls and yes, the titanium element has very good reviews.

But be under no illusion of using the panels to run other stuff.

[JamesC]

off course, you can do a half arsed installation and steel from AC and slash the installation price in half as well as kiss your savings good bye...

[pietpetoors]

Thanks, there goes that idea, but I am glad I asked first, sounded like a good solution.

[ChrisF]

Thanks, there goes that idea, but I am glad I asked first, sounded like a good solution.

nou nie SO vinnig luister vir die skare nie ...


few basics - for "Alternative power sources" we MUST think differently !!!

We are used tho think like THIS :

From the KWIKHOT catalogue:
100 liter geyser use a 2 kW electric element
150 liter geyser use a 3 kW electric element
200 liter geyser use a 4 kW electric element

You will find the 100 liter unit in the typical bachelors flat, and the 200 liter unit in the typical 3 bedroomed house.

First some basic mathematics – It takes a certain amount of “Energy”(Q=m*c*t) to heat the water.“Power” is simply Energy divided by time.And thus one can calculate that for the data in the Kwikhot catalogue that it takes 2,3 hours to heat these geysers from 15 degrees to 55 degrees.However in reality you never drain the geyser 100%, thus at worst you are heating from about 35 degrees to 55 degrees.For these conditions it takes just more than an hour for a geyser to re-heat after being drained excessively. And so we got used to expecting a geyser to take no more than an hour if the previous person was excessive with their water usage.In fact normally the water is ready in less than 30 minutes for the next bath or shower.


And somehow we have come to the conclusion that any geyser that cant heat water in "60 minutes" must be cr@p .....



Now TRY to think differently -

Let's look at a 150 liter geyser, typical small family.

Let's assume the following:
- 8:00 family leaves for work and school
- 8:00 geyser at 40 degrees
- you have 600W worth of panels on the roof for SIX hours
- the PV will heat that water to 61 degrees before you get home !!! :)


you have just saved 3,6 kW.h in a single day, or somewhere between 1000 and 1300 kW.h per year !! Depending on your rate etc etc you are looking at about a 5 year payback period. THIS is if you go expensive and include a geyserwise unit that ups your usability a LOT, AND you still have Eskom if needed.



Pieter my neighbour is doing a LOT of research into this at the moment.


We will be VERY interested to hear more of your elements.

Pieter the next step is to hear from your suppliers about 36V or 48V panels delivering between 600W and 900W ....


Tyd dat ons koffie drink, hier is n LEKKER besigheids geleentheid !!

[JamesC]

Chris, agreed.

But you need to factor in the basic fact that retrofitting a normal geyser is not smart because the standing losses are very high.
Factor in a standing loss of over 2kw for your kwikot - look on the plate of the geyser, by law it must be displayed.

[ChrisF]

Chris, agreed.

But you need to factor in the basic fact that retrofitting a normal geyser is not smart because the standing losses are very high.
Factor in a standing loss of over 2kw for your kwikot - look on the plate of the geyser, by law it must be displayed.

James do you have the heat loss figures for a "new" geyser ?

would it not amount to the same if you just used some Isotherm/Think Pink to wrap it ?


In fact I am under the impression more heat is lost due to long runs of uninsulated hot pipes ....



truth be told - to be truly energy efficient means one has to look at each component and save energy where ever possible :)




what I LIKE about the PV option is no plumbing changes required. New element, bit of wiring by an electrician, new COC and you have a safe functional system with minimal intrusion .... :)

[JamesC]

Chris,

Your first post, although technically sound, does not really reflect a real life scenario.
The following (after seven years of doing this) is more likely:
- You all showered last and have dropped the temp well below 30. In summer cold water temps run between 15-18 degrees. (Also factor in the standing loss - on a kwikot you are looking at over 2kw on a 150 and over 3kw on a 200. In laymens terms this equates to double digits lost in terms of temp)
- The maid is coming in today - so although mom and dad is at work and the kids are at school, the domestic is cleaning up and she does so all day long with guess what? Luke warm water.
- You get home tonight after it being a beautiful sunshine day and cannot understand why your R22k investment is sitting at 40 degrees. Mommy is not happy. Kids are unhappy but ESKOM is not.
- 6 hours of direct sunlight? Optimistic a touch I think. As you will know, PV is very touchy to that and the output drops dramatically. This is where heat evacuated tubes/flat plates or whatever tickles your fancy does well as it essentially converts uv to kj. And hence the Q factor is of importance.

Don't get me wrong. I agree with you: great product, much simpler installation. It just irks me when they create expectations that cannot be met.

But they are undersizing it to be competitive. I suppose if you buy into that, with both eyes open, then ja, for sure, a very good opportunity. One that I am certainly looking into and not just knocking.

[ChrisF]

James in fact my figures are on the conservative side :)

- the kw ratings came straight from the Kwikhot sight. But these merely served to confirm the norm we came to expect - to be able to have hot water again in less than an hour.
- 6 hours a day of sunlight is the very conservative figure used in industry to calculate PV systems. My personal tests shows longer hours are easily attainable, but for the sake of calcs I stick to the industry norm. I have seen about 50% of the PV output 30 minutes after sunrise !! :) :)
- maid running the hot tap all day long ... boet NOTHING is going to save your electrical account in this case !!!! Even so, a PV system can go some way to giving her luke warm water, without using eskom power .... but this is simply an impossible situation, as NO geyser was ever intended to heat water on permanent run through ....

- getting home to luke warm water - THIS is why I said use a geyserwise that WILL ensure the water is heated by Eskom in that last 45 minutes before you get home. I FIRMLY believe the geyserwise MUST form part of such an installation to ensure mommie stays happy ...

- investment figure :) :) A FRACTION of the amount you mention !!!!!!! :) :) :) As they say - watch this space for more info :) :) :)



Evacuated tube vs flat plate vs PV .... NOW this is an interesting debate .... not to mention heat pumps


After a few hundred installations, herewith my opinion/experience :

- Evacuated tube - seen way too many broken tubes ! And when they dont break the system boil the water and the components fail in less than 24 months due to excessive temperatures ....

- Flat plates - technically less issues than with the evacuated tubes.

with BOTH we have endless hassles with clients NOT adapting to the Eskom timer times ....

also another issue - well it is free heat so lets STAND under that shower and empty the geyser ....

User issues (life style and usage) are by far the largest component of complaints


PV panels - YES, these are greatly undersized !! They will at best work as shown in my previous post where it has the working day to heat up the water. We are looking at getting 900W worth of heat into the system, at a reasonable cost .... (WONT work for the house with the maid..) ..... also considering another approach for the PV systems ..... let's see what comes up when a mechanical engineer and an electrician starts experimenting ....


Heat pumps - doing a 450kW installation in February. I BELIEVE in this technology - for large capacity users. For various reasons I am not convinced this is the optimal solution for a home owner.



PS - YES, one should never create unrealistic expectations.

[pietpetoors]

Thanks Chris, if you have free time next time I go to CPT we can surely have a cup of boeretroos.

I think it will work good in our situation.
Now that the kids are out of the house our situation is like this:
Only me at home during the day and I do not use hot water for anything, so system has whole day to heat the water.
After 18h00 we might use one basin of hot for the dishes and at about 22h00 takes 2x shower. 150 liter geyser when at temp by 18h00 will be able to handle this.

I can then switch on the 220 volt by means of the, already installed timer, to heat the water tomorrow morning from 5 to 5:30 just to take the worst cold out of the water for early morning, wakeup facewash.

So it means that I can cut it from my current 4 hour geyser on-time (by timer, not sure how often thermostat switches it on and off) to 30 minutes of on time.

[pietpetoors]

What I also thought of doing is;
To run a class 1, 50mm pvc pipe on the inlet pipe. My house's roof is a concrete slab, so it is flat and enough room for this. It can lay in the sun and heat up and because it is 50mm it can be a big volume of water.

So when one start using hot water in the evening the water entering the geyser will already be warmer than the normal water.
As I see it, every degree the water entering the system is hotter, the less you need electricity to warm the water.

Since the geyser is the thing that uses the most electricity in our house I think it is worth doing anything to safe.
Not that we have a high bill... I heard of people with very high electricity bills, we are running at about R600 per month.
So my main aim is not to safe an extra R100 per month, it is more a thing of having a passion for doing things the green way and not to be dependable on eskom to supply us with what we need.

[Mr_B]

- Evacuated tube - seen way too many broken tubes ! And when they dont break the system boil the water and the components fail in less than 24 months due to excessive temperatures ....

Shhoooo... now you scaring me! I've just installed an evac tube solar geyser heating system... let's hope I don't experience these problems! Must say the guys that did the installation have given me excellent service. Had a leak over the Christmas holidays, contacted the salesman, who arranged to have it repaired right away!

Still waiting for my Dec utility bill to see what savings I am making!

[ChrisF]

- Evacuated tube - seen way too many broken tubes ! And when they dont break the system boil the water and the components fail in less than 24 months due to excessive temperatures ....

Shhoooo... now you scaring me! I've just installed an evac tube solar geyser heating system... let's hope I don't experience these problems! Must say the guys that did the installation have given me excellent service. Had a leak over the Christmas holidays, contacted the salesman, who arranged to have it repaired right away!

Still waiting for my Dec utility bill to see what savings I am making!

all is not lost


the breakages are a sad reality - but covered by your warantee, so please dont loose sleep over this.


the high temps - check where your pressure valve discharge to - keep an eye on the water coming out of here .... it should NOT be a steady stream. This is a dead give away of too much heat (pressure) in the system.


when they MATCH the number of tubes to your usage it does work well. The problems start since they size it for bad winter days, then have way too much heat in summer.

[Mr_B]

Chris, hopefully I'll avoid this situation. The system was installed in November and has been programmed to allow a max temp of 70deg. I've been monitoring it pretty frequently and have noted a max temp of 72deg on a very hot day... even got into the roof to inspect for leaks, hence why I found that one.

[ChrisF]

Chris, hopefully I'll avoid this situation. The system was installed in November and has been programmed to allow a max temp of 70deg. I've been monitoring it pretty frequently and have noted a max temp of 72deg on a very hot day... even got into the roof to inspect for leaks, hence why I found that one.

sounds like a pumped system - WITH the correct safe setup.


the fun starts when people cut corners to save money and put in too many tubes with NO way of stopping the overheating .....

[pietpetoors]

My mother have one of those.
In winter I have have to climb into the sealing to set the pump slower and in summer I must set it faster.

After reading your remarks I realize how important it is to go visit her after winter to set the pump faster again as soon as the days are getting warmer.

[Stef]

I also believe in cutting heat losses i.e the long runs of pipe etc..

But I think a geyser system where one can't drain it completely and that has some sort of pre-heat stage is key. It's that first 30 degrees that takes a lot of energy to heat.

[ChrisF]

I also believe in cutting heat losses i.e the long runs of pipe etc..

But I think a geyser system where one can't drain it completely and that has some sort of pre-heat stage is key. It's that first 30 degrees that takes a lot of energy to heat.

Stef I am looking at doing a PV system purely to preheat the supply water in a primary geyser .... exactly for the reason you mention ... but this is NOT a cheap exercise .... still playing with the idea though ...

[Thabogrobler]

flange type element which fits only some lesser quality geysers on the market

Oh, I always thought Kwikot and Franke were some of the better quality?
I have a new Kwikot and it has a flange type?

What is a good make then?

Na so 100 jaar in die bedryf is my keuse:

1. W.E Geysers se Duratherm reeks - maar hul naverkope diens suig.
2. HeatTech - 2mm Steel tank vs all others 1.6mm. The Builders whorehouse housebrand is a HeatTech - VERY affordable!
3. Franke - Good after sales service
4. Kwikot
5. Gap

In die Kaap is daar ook Glasvesel geysers beskikbaar wat teorities vir altyd moet hou?

Pieter, daai element ouens se hoofkantoor sit in die Kaap? En hul groot besigheid is geyser bestuurs stelsels?

Ek gaan more weer na die plaaslike kantoor toe en sal kyk of hul demo unit al up and running is.

[Thabogrobler]

Pieter... ek dink James vra of jy ie skroef tipe kan kry want volgens die prentjie is dit nie 'n skroef tipe soos Kwikot vat nie

Hau my baas,

Die Kwikot hy vat die spiral element!

[Thabogrobler]

Sal die nie 'n beter roete wees nie?

http://www.nu-inc.co.za/nuthermo/induction-geysers/" onclick="window.open(this.href);return false;

[ChrisF]

Sal die nie 'n beter roete wees nie?

http://www.nu-inc.co.za/nuthermo/induction-geysers/" onclick="window.open(this.href);return false;

very interesting concept.



need to check these numbers again when I am properly awake ....



at first glance it looks like a "flow through geyser on steroids"

[Stef]

I also believe in cutting heat losses i.e the long runs of pipe etc..

But I think a geyser system where one can't drain it completely and that has some sort of pre-heat stage is key. It's that first 30 degrees that takes a lot of energy to heat.

Stef I am looking at doing a PV system purely to preheat the supply water in a primary geyser .... exactly for the reason you mention ... but this is NOT a cheap exercise .... still playing with the idea though ...

I actually thought of running copper pipes just under the tiles of my roof...just the weight that might be a problem and of course winter time it might be a cooling stage LOL

Also thought of using grass cuttings to preheat water

[Mud Dog]

Not sure that I fully agree with these figures / findings, but some interesting reading all the same ....


http://www.moneyweb.co.za/moneyweb-econ ... ce-at-home" onclick="window.open(this.href);return false;

[Family_Dog]

I fitted an *indirectly heated 200-litre solar geyser system some years back and having nothing but good comments to make about it. In summer, I never use electricity while in winter, although you can come right without additional heating and can handle luke-warm showers, I now do use AC mains to bring it up to a higher temperature. The use of electricity in Winter is minimal because the water is only required to heat up from ±40° to about 60°, not from an ice-sold base of 15°C.

My monthly electricity bill fell by around R800, so I suppose our local Municipal electrical charges are higher than Tswane - Tshwane - Pretoria.

* Indirectly, i.e. it makes use of glycol that runs through two roof-top panels, this is a necessity in areas where frost is prevalent in Winter.


-F_D

[ChrisF]

Not sure that I fully agree with these figures / findings, but some interesting reading all the same ....


http://www.moneyweb.co.za/moneyweb-econ ... ce-at-home" onclick="window.open(this.href);return false;

uhm ja .... a professional person providing a professional opinion, then excluding maintenance and interest costs ....


then making NO allowance for the days that the solar dont work, or people requiring the electrical element early morning to ensure hot water for the morning shower .... THIS however comes back to the concept of live styles that are not conducive to max savings .....


his gas-stove calcs are sadly SPOT ON

[ChrisF]

I fitted an *indirectly heated 200-litre solar geyser system some years back and having nothing but good comments to make about it. In summer, I never use electricity while in winter, although you can come right without additional heating and can handle luke-warm showers, I now do use AC mains to bring it up to a higher temperature. The use of electricity in Winter is minimal because the water is only required to heat up from ±40° to about 60°, not from an ice-sold base of 15°C.

My monthly electricity bill fell by around R800, so I suppose our local Municipal electrical charges are higher than Tswane - Tshwane - Pretoria.

* Indirectly, i.e. it makes use of glycol that runs through two roof-top panels, this is a necessity in areas where frost is prevalent in Winter.


-F_D

Eric these are THEE BEST systems !!


less issue with panels freezing

less corrosion issues

less issues with lime deposits on the inside of the panels destroyeing the efficiency



sadly substantial cost premium, but WELL WORTH IT !!

[ChrisF]

neighbour picked up his PV-element kit yesterday


will have a closer look today .... :)

[JamesC]

Pls keep me posted Chris

[pietpetoors]

[ChrisF]

Pls keep me posted Chris

WILL do :)


keeping a CLOSE eye on this one !!!!!

[ChrisF]

Riaan is NOU in die dak besig om daai element in te sit ....

sal so tussen sy ander projekte die panele op die dak sit, ens ....

[Borntofish]

Waiting to see the results....

[ChrisF]

Waiting to see the results....

self ook ....


My neighbour is an electrical contractor.

Showed away work on Monday to do a project for one of his large clients TODAY ... gets to site: "Oooo, we are running late, see you next week."



all frustrations, and lost profits, aside, at least this meant he could start his own geyser conversion today.



THIS one I am watching CLOSELY

[JamesC]

I might be selling one tomorrow morning and installing it next week. Will keep you posted

[Mr_B]

I might be selling one tomorrow morning and installing it next week. Will keep you posted

Confused... selling? Don't you mean buying?

[Mud Dog]

I might be selling one tomorrow morning and installing it next week. Will keep you posted

Confused... selling? Don't you mean buying?

James may be a supplier / installer.

[JamesC]

Supplier and installer for seven years now...

[Hannes Meyer]

[ChrisF]

So Riaan installed his unit.

2200W AC / 750W DC
2x300W solar panels
Geyserwise dual controller, and some other bits ...


Short version after the first week:
even with some heavily overcast days - it WORKS !!!
HOWEVER, not maid proof !!

[Scott]

To add to this all I was adding up running solar geyser with 12 volt heat pump of panel and through a gas geyser with thermostat so gas only kicks in at 50 deg celc.The big problem I have had is Hilux eating funds and hail storms in Benoni so I have been thinking on ckicken wire frame to protect instalation.What do you guys think?

[Mud Dog]

I haven't given it too much thought although I have to admit that the issue had crossed my mind about how hail resistant the solar panels actually are. The chicken mesh idea sounds like it could work, but then it has to be strung fairly taught and maybe supported between each panel.

What are the facts about PV panels and hail resistance?

[ChrisF]

There have been some LARGE industrial PV installations in the Joburg area ..... these seem to stand up to the hail storms.

[oxydog]

I fitted an *indirectly heated 200-litre solar geyser system some years back and having nothing but good comments to make about it. In summer, I never use electricity while in winter, although you can come right without additional heating and can handle luke-warm showers, I now do use AC mains to bring it up to a higher temperature. The use of electricity in Winter is minimal because the water is only required to heat up from ±40° to about 60°, not from an ice-sold base of 15°C.

My monthly electricity bill fell by around R800, so I suppose our local Municipal electrical charges are higher than Tswane - Tshwane - Pretoria.

* Indirectly, i.e. it makes use of glycol that runs through two roof-top panels, this is a necessity in areas where frost is prevalent in Winter.


-F_D

Eric these are THEE BEST systems !!


less issue with panels freezing

less corrosion issues

less issues with lime deposits on the inside of the panels destroyeing the efficiency



sadly substantial cost premium, but WELL WORTH IT !!

Guys, do you have a name and contact details? I'm doing some research now as well and want to make an informed decision. I want an indirect system that connects to my current geyser.

[ChrisF]

Contact Solar Energy -
Doran Schoeman
082 973 7876


NOT the cheapest.

BUT the best.

[oxydog]

Thanks Chris, will give them a call.

[oxydog]

Chris, do you know if they operate in Pretoria?

[ChrisF]

Chris, do you know if they operate in Pretoria?

Yes.

They are all over SA with the main guys sitting in Joburg - other side of Bloem is Joburg to this Capie ...

[oxydog]

Chris, do you know if they operate in Pretoria?

Yes.

They are all over SA with the main guys sitting in Joburg - other side of Bloem is Joburg to this Capie ...

OK, so I phoned Doran, but it turns out they only operate in the Western Cape!

[ChrisF]

Chris, do you know if they operate in Pretoria?

Yes.

They are all over SA with the main guys sitting in Joburg - other side of Bloem is Joburg to this Capie ...

OK, so I phoned Doran, but it turns out they only operate in the Western Cape!

Okay, will check in the office tomorrow - their joburg boys flies down to do the training down here !!

[ChrisF]

Their Cape Town details -
Marisca Thomas
SEG Solar Energy Cape Town
marisca@solarenergy.co.za


There Joburg details -
For any queries please feel free to contact us on 021 385 0123 or Johannesburg on 011 326 3957

[Haboob]

Re: DC Geyser Element

Contact Solar Energy -
Doran Schoeman
082 973 7876


NOT the cheapest.

BUT the best.


Hi Chris,
I see nothing mentioning the Eastern Cape...

[oxydog]

Thanks Chris, I'll try the Jhb number!

[ChrisF]

Re: DC Geyser Element

Contact Solar Energy -
Doran Schoeman
082 973 7876


NOT the cheapest.

BUT the best.


Hi Chris,
I see nothing mentioning the Eastern Cape...

Eastern Cape .... whats that .... wheres that ??


Phone MARISCA :)


Solar energy distributes country wide. They will be able to direct you to their approved installers, even in rural areas such as the eastern cape ...