This should do it

 

 

With that view forget the rust, rather bring up two camping chairs and four beers!

I like working with copper geysers, never bought a new one got them secondhand at local scrap yard for R600 or in properties I bought, you get a leak you fix it!

I use thermo siphon, cheap and never breaks, perfectly tuned currently up to 10 meter distance from the geyser. On old 100kpa horizontal copper geysers with warm in and outlets on the side a T junction for your circulation works 100%

Keep an eye open for flat pates they get thrown away at scrap yards or stand disconnected on roofs cheap cheap in gumtree . Learn to do some plumbing, low tech low risk.

I have started to use the 22mm white cobra pipe on the cold circulation side, try not to use connections unless outside on your roof or at the geyser with potential drips in the tray, cheaper than copper much easier to form and work with and I will not be interested in buying yours secondhand at the scrap yard!!

Copper on the hot side.

System for 3k easily possible 

I take it the tube overheating problem is with high pressure geysers? I have 3 low pressure tube geysers on our cottages which are not used during the week and they boil regularly, but being low pressure they just blow a bit of water out of the vent pipe with no harm done.

On 5/3/2016 at 10:51 AM, jdp said:

If you are installing retrofit and want to add a tank I was told to stay away from Kwikot tanks as they tend to burst in 2 years time.

I can not comment on any other brand than ITS as that is what I have. The system look a lot like what Carl showed here on the forum. Same controller and tubes.

 

I can attest to that, although I do not have a solar water system currently, in the 5 years of living where I live now, I had to get the Kwikot geysers replaced 2 times already due to bursts.

3 hours ago, DeepBass9 said:

I have 3 low pressure tube geysers on our cottages which are not used during the week and they boil regularly, but being low pressure they just blow a bit of water out of the vent pipe with no harm done.

@DeepBass9 i was wondering if it really does do no harm?

Every time your geyser boils it puts your system under undue thermal stress and the question for me is how long will it last? 

@Kloon forgot to mention that Sunscan , ITS solar & SolarJoy seem like very good solar thermal companies and they are all located in Cape Town.

17 hours ago, ebrsa said:

What would be interesting is an analysis of evacuated tubes plus grid electricity vs evacuated tubes plus heat pump electricity consumption and capital financing and replacement costs.

Based on my experience and for my personal situation a solar collector plus electricity backup will beat the heat pump scenario hands down.

Last year our total water heating bill was R43, (42 Kwh at R1,03 / unit) so it would be hard to justify spending R17 000 on a heatpump.  

For households or guest houses that need hot water 24/7 i am sure a heatpump will make more sense.

58 minutes ago, Carl said:

@DeepBass9 i was wondering if it really does do no harm?

Every time your geyser boils it puts your system under undue thermal stress and the question for me is how long will it last? 

Also when water boils it can deposit minerals that could start clogging things up. Just look at the inside of your kettle and you can normally see the calcium deposits. The same thing would happen in the geyser if heated up excessively.

1 hour ago, Carl said:

@DeepBass9 i was wondering if it really does do no harm?

Every time your geyser boils it puts your system under undue thermal stress and the question for me is how long will it last? 

5 years so far...I'm not sure what undue thermal stress is. What happens is the water boils a bit in one of the tubes, then pushes some water out of the tube, which is replaced with cooler water from the geyser tank. Low pressure geysers are actually no pressure geysers as they are open to the atmosphere via the vent pipe, so if a bit of water is blown out, it is topped up again with cold water immediately. Its not like the whole geyser is filled with boiling water like a kettle, only a few steam flashes in the tubes. When the boiling in the hot sun stops, I'll go and check what the problem is..... 

Carl I agree that if you only do the geyser alone then that is the way to go. If you are going to install PV as well and want hot water day and night then I found that the heat pump will do the job as it will run day , night , rain or shine 24/7, 365, I do not have to worry about overheat in summer and I don't have to worry about cold water during cloudy days. I dont have to worry what will happen if the pump stops working because there is not water pressure.

Again that is what I found with our set-up.

Glad to see I am not the only one with the overheat problem as suggested in previous post.

I was told many years ago:
1-4 people - EV and flat plate collectors will work quite efficiently.
More than 4 people - heat pumps are more cost effective.
And if you have need a lot of hot water daily - heat pump.

Very informative to read about all the different experiences and requirements with solutions in each instance. I was asked by two friends to suggest a water heating solution for their two bedroom guest house with a separate geyser for the guests. We are about 100 Km north of Cape Town on the West Coast at 33.36 degrees South with plenty of sunshine in summer. That is when they have most of their guests. It seems a shame to waste all that solar heat but I understand the reliability of a heat pump. Our electricity is charged on a sliding scale and highest rate for over 600 Kwh will be R2.0406 per Kwh for the 2016/17 year. So it would seem that solar with electric heating element backup may be the most economical option, both capital and electricity consumption costs. But I have zero experience of heat pumps except for what I have read on the forum and elsewhere. Of coarse if Eskom falls apart again and start load shedding, which is not unlikely, solar will still produce some hot water. Would be grateful to hear the views of others on the forum.

EV tube system with Geyserswise and a 2kw element and you are covered on the West Coast is what I would have done.

Retrofit the geysers, the sales guys want to up-sell you but there is another way.

We all know geysers are going to go / burst, and that is covered under your insurance so when they burst, then you replace them.

Thanks for you advice TTT. That is what I use very successfully with little need for turning on electricity which I do manually. Just hope fellows with experience of heat pumps will give their views too. Considering all aspects is always better. Masure twice and cut once always applies.

Wise move!

Let me add:
I said somewhere here before, heat pumps are for more than 4 member houeseholds as well as high usage of hot water users.
EV tubes and flat panel are good for households with 4 or less people that come home every night.

Thinking about it, maybe hotels and the like should have EV tubes and heatpumps on timers linked to temp, for they have a LOT of wastage from guests. 

We are 4 members in our house hold, not sure were TTT is getting that from so can not comment on that. I was told by all the hot water people it  is about the size of the tanks you have to take into account. You get smaller and lager heat-pumps, They are specked to heat the amount of water you want to heat up.

If we use water at night the heat-pump will run for 30 minutes. The heat-pump uses 1Kw of power to generate 4kw of heating power. This was the first thing I put in before I went solar. My water heating went from 4kw down to 1kw to heat the same amount of water. The unit cost me R12K on the eskom rebate.

So as stated above in all my other posts. If I had to do this again, I would not get the EV tubes as I have PV power.  I like the heat-pump as it makes hot water any time at 1/4 ration of a normal geyser.  EV tubes work well in summer but have issues with overheating if you don't have water in the pipes and if it is cloudy you dont get hot water.

So I have both EV tubes and heat-pump. For me the heat-pump wins hands down. Less to worry about in my case.

If I have to choose 1 system and only one I would still choose the heat-pump as stated above. Less to worry about if things go wrong.

If they could guarantee me that the EV Tubes would not malfunction ever again then maybe that is the way to go and then just use the element to heat the water when it can not (which is every night in our case).

So if you can get both then that is the best option.

 

10 minutes ago, jdp said:

... not sure were TTT is getting that from ... 

From articles and documentation done years ago by a number of installers and academics who also argued the pro's and cons of EV versus heat pumps.

Also too large a geyser on EV becomes problematic ito collectors and to heat it when it is completely cold geysers ... heat pump will win. 

For the rest JDP, I agree with your for the 1st time on this matter.  

 

Ps. We are well on the way into winter and I still have not switched the Geyserwise on to use Eskom to heat the water. Family is behaving quite well.

PLUS they use buckets to catch the wasted shower water, their idea, which is then used to flush their toilets.

Water is down from +-1000l per day to +-550l per day.

26 minutes ago, jdp said:

The heat-pump uses 1Kw of power to generate 4kw of heating power.

That's a pretty decent COP (Coefficient of Performance). Smaller heat pumps are closer to 1:3 usually. There's a Spanish product on the market with an even smaller heat pump (<< 1kw) that uses a collector on the input side. You can mount this below your PV panels. This way they get a very decent COP with a very small compressor.

The specs of the heat-pump. It has a COP of 4.

Some interesting info on there. Like the circulating water flow volume. If you connect it to a 100 liter tank it will heat it in an hour, but it will do it 5 degrees at a time and cycle the tank 8 times to do it :-)

So normally some kind of workaround is installed for this, but if you don't do it, then people get this problem where 5 minutes into the shower the water is cold. Simply, the heat pump turned on, took the 15 degree water at the bottom of the tank and heated it to 20, then dumped it right at the top of the tank where the shower draws from... :-)

The hot water is dumped at the bottom of the hot tank not at the top. The tank also has that device (not sure what the name is) to keep the water from mixing.

 

@jdp I am almost certain that the hot outlet from the heat pump goes to the top of the geyser. 

The retrofit kit normally consists of a Banjo valve that creates an extra hot water connection point at your TP valve.

The extra cold water connection is normally just created with a T piece at the cold inlet to the geyser.

ITS use a "Loading Valve" that's preset at about 48 ⁰C on the hot water output of the heat pump. 

Remember I have both systems. The heat-pump joins a T in the hot line that comes from the EV tubes. This pipe goes to the bottom of the hot tank.

 

Here you can see. HT is the hot tank CT is the cold tank and where the water comes from and goes to. HP is the heat pump T in to the line that goes to the bottom of the hot tank.

I was told by Stepahn from ITS it has to go there so that the colder water does not mix with the hotter water.

 

 

OK, so i am pretty confused with your setup.

Do you have a pre-feed system with the cold tank supplying the hot tank  and the ET collector and heat pump sitting between them?

I will post the ITS setup diagram when I am back home. But this is how it works. I have 2 tanks. A hot tank that sends the water to a mix valve where cold water is added and then it goes to the house. That pipe is at the top of the hot tank. Then there is a pipe that connects the hot and cold tanks at the top. This lets water flow from the hot tank to the cold tank when the ET and heat pump works. Then we have a pipe that feeds cold water into the cold tank at the bottom of the cold tank. This is a T with the loops. This pipe then continues to the pump and to the ET panels. The pipe that comes back from the tubes connect to the bottom of the hot tank. The heat pump has a T on the hot line before the hot tank and a T on the cold line between the ET pump and cold tank .

So if it is the ET system or Heat pump that warms the water it will pull colder water from the bottom of the cold tank. Then heat it up and dump it in the bottom of the hot tank. Then the water flows from the hot tank to the cold tank via the top pipe. This cycle continues until the sensor at the bottom of the cold tank shows 54 degrees if the heat pump runs. And if the ET does the work it just keeps on going .