Solar Water Heating - has anyone tried it?

[Encid]

I really like the idea of converting energy from the sun into electrical energy and then into thermal energy.

 

In Australia where I originated from I have seen many homes with solar panels and hot water tanks on the roofs of suburban homes (particularly in the northern tropical states)... but none at all in Thailand.

Maybe they are out there, but certainly not in the areas where I live and travel around.

 

My future home build will have it's own hybrid solar energy system, but to use that system to power high wattage demand electric water heaters seems such a waste of energy rather than using a dedicated solar water heating system.

 

Have any forum members installed such a system and are you happy with it?

 

Do you have a backup hot water service such as a demand electric water heater that can provide hot water when the weather is miserable like this?

[Crossy]

I would go direct from sunshine to hot water, it's far more efficient than going PV => water heater.

 

And it is far, far cheaper to implement.

 

A mate has had 2m² of hot water solar for nigh on 20 years, on really sunny days his water will actually boil! (ok, so he says, I've never actually observed it)

 

 

 

[Bandersnatch]

I have had solar thermal for 4 years now. It has a 200L insulated tank and as water is heated in the panels it rises and enters the top of the tank, pushing the coldest water back down into the panels to be reheated. The system feeds 2 bathrooms and the the kitchen sink.

 

 

There is also an immersion heater which can be set to come on a different times of the day and when the water reaches a predetermined temperature. It is currently not connected as the water is still scolding hot in the morning.

 

 

Quote from my blog so figures might be a little out of date:

 

 

"In Thailand electric water heaters are normally located in the room where the water is being used, normally under the sink. Assume the water heaters are 5kw and and three water heaters in total are run for 30 minutes a day = 2.5Kwh/day @ ฿4/kWh = ฿10/day = ฿3,650/year (adjust parameters to match your personal circumstances)

 

I paid ฿30,000 for my solar thermal unit compared to  3 electric water heaters at say ฿6,000 each = ฿18,000 – ฿30,000 = ฿12,000 /฿3,650 in saved electricity per year = 3.28 years to payback. As it has no moving parts it should last for several more years to come. I am happy with my investment and enjoy as much hot water as I like knowing it’s all free. "

 

 

Edited August 31, 2022 by Bandersnatch

[Encid]

21 hours ago, Bandersnatch said:

I have had solar thermal for 4 years now. It has a 200L insulated tank and as water is heated in the panels it rises and enters the top of the tank, pushing the coldest water back down into the panels to be reheated. The system feeds 2 bathrooms and the the kitchen sink.

Is the system pressurized by your home water pump?

 

I note the use of PPR pipe and fittings for the hot water side.

No additional insulation required?

No temperature loss from tank to outlets in the bathroom(s)?

How far away are the outlets?

 

21 hours ago, Bandersnatch said:

There is also an immersion heater which can be set to come on a different times of the day and when the water reaches a predetermined temperature. It is currently not connected as the water is still scolding hot in the morning.

So apart from the immersion heater you don't have any demand electric water heaters?

 

[worgeordie]

I have had Solahart solar water heater for a least 30 years,

installed it when building our house so fitted hot and cold 

water pipes ,works great ,maybe 2-3 days in the cool months

when it rains all day ,the does not get hot ,but the other 362

days of the year ,the water is very hot ,having hot water to

kitchen and bathroom sinks and especially the bath is great.

 

Not mixing water and electricity is another benefit,wonder

how many people in Thailand die in the bathroom from

faulty water heaters, 

regards worgeordie

 

 

 

[Bandersnatch]

26 minutes ago, Encid said:

Is the system pressurized by your home water pump?

 

I note the use of PPR pipe and fittings for the hot water side.

No additional insulation required?

No temperature loss from tank to outlets in the bathroom(s)?

How far away are the outlets?

 

So apart from the immersion heater you don't have any demand electric water heaters?

 

 

 

No additional insulation required? no

No temperature loss from tank to outlets in the bathroom(s)? No

 

 

So apart from the immersion heater you don't have any demand electric water heaters? - No -  two showers a double bath and three sinks

 

How far away are the outlets?

The solar thermal is directly behind me in this photo. First door is the mechanical where I have pumps and filters. Second door is a bathroom  with an ensuite behind it. The windows at the end are the kitchen.

 

Due to expansion of the water as it rises in temperature it is under pressure and the system has a pressure release valve. It is topped up with cold water by a demand pump.

 

 

    

[Encid]

25 minutes ago, worgeordie said:

I have had Solahart solar water heater for a least 30 years,

installed it when building our house so fitted hot and cold 

water pipes ,works great ,maybe 2-3 days in the cool months

when it rains all day ,the does not get hot ,but the other 362

days of the year ,the water is very hot ,having hot water to

kitchen and bathroom sinks and especially the bath is great.

Are you in Thailand?

 

I just googled "Solarhart Thailand" and discovered that Boonthavorn sell them... this one appears to be a 300 litre model.

And it appears to come with an Over-Temperature Protection System to prevent over performance during periods of higher solar radiation and lower hot water draw off.

 

[BritManToo]

3 minutes ago, Encid said:

Are you in Thailand?

 

I just googled "Solarhart Thailand" and discovered that Boonthavorn sell them... this one appears to be a 300 litre model.

And it appears to come with an Over-Temperature Protection System to prevent over performance during periods of higher solar radiation and lower hot water draw off.

 

200kbht seems a tad expensive. 

[Encid]

8 minutes ago, BritManToo said:

200kbht seems a tad expensive. 

They also appear to be imported from Australia.

 

 

From what I have researched this afternoon the same model can be fully installed in Australia for around $5,000 AUD (or 125,000 THB).

[Tarteso]

Thinking to buy this one ???? 

18.000.- Deliver to Phuket..

25.000.- Deliver to anywhere.
 

 

Check out Solar hot water heater 150 litre. Stainless stee...at 22% off!฿17,950.00 only!Get it on Lazada now! https://s.lazada.co.th/s.SoOQt

Edited September 1, 2022 by Tarteso

[Muhendis]

I've been using my home brew solar hot water system for the past ten years. Water can generally get just a tad too hot.

Flat panel (1.2 × 1.2m) heat exchanger on the well house roof.

200 ltr insulated tank and mini circulation pump below in well house.

Pump and electronic control system powered by 65w solar panel. 

It's pressured from the cold supply so has an expansion tank.

[sezze]

9 hours ago, Muhendis said:

I've been using my home brew solar hot water system for the past ten years. Water can generally get just a tad too hot.

Flat panel (1.2 × 1.2m) heat exchanger on the well house roof.

200 ltr insulated tank and mini circulation pump below in well house.

Pump and electronic control system powered by 65w solar panel. 

It's pressured from the cold supply so has an expansion tank.

I do love home brew things . Hot water prob is the easiest of all home brews around for Thailand , given the solar input daily . Having a extra immersion heater ( easy available nowadays , including hot water circulation pumps ) and a temp switch and you do have hot water whole year round .

Pls inform us your home brew system...

just pressure tank , lines to a closed box with metal ( copper, stainless , galvanized?) pipes and a circulation pump including a extra bladder tank and done?

What about water overheating ? some kind of pressure valve ?

[sammieuk1]

I had a massive tank and solar panel contraption on the roof when I lived in Turkey in August it regularly blew off steam like geezer from a plastic vent pipe .

On my return from visiting here for a month a neighbor said he had seen a big mouse he meant a rat enter my roof space an sure enough he was right it had gnawed though the pipe and flooded the room below with everything now having a green fury beard .

 

So I would advise mounting the tank at ground level  or in my case forgetting it altogether ???? 

[Muhendis]

26 minutes ago, sezze said:

I do love home brew things . Hot water prob is the easiest of all home brews around for Thailand , given the solar input daily . Having a extra immersion heater ( easy available nowadays , including hot water circulation pumps ) and a temp switch and you do have hot water whole year round .

Pls inform us your home brew system...

just pressure tank , lines to a closed box with metal ( copper, stainless , galvanized?) pipes and a circulation pump including a extra bladder tank and done?

What about water overheating ? some kind of pressure valve ?

The heat exchanger was built and tested in UK where 15mm copper pipe is very easy to get. I have a number of parallel 15mm pipes 'T' jointed to short lengths of 22mm. Thin aluminium sheets formed round the 15mm pipes to increase heat capture. Insulated copper pipe to circulate water to stainless storage tank. Water comes from cold supply under house pump pressure via an NRV or check valve. Expansion tank is a bladder tank on the hot outlet side together with an over pressure relief valve. There is also an air relief valve at the highest point of the system.

 

The solar panel also acts as a sun detector so if no sun then circulation pump won't run. I had to add some power start circuit to ensure that the pump would start as soon the panel output got high enough.

 

I monitor the water temperature at the tank and the heat exchanger and Adjust the circulation pump speed for hotest tank water.

[Encid]

8 hours ago, sammieuk1 said:

On my return from visiting here for a month a neighbor said he had seen a big mouse he meant a rat enter my roof space an sure enough he was right it had gnawed though the pipe and flooded the room below with everything now having a green fury beard .

Thai rats seem to leave PVC and PPR piping alone... but they love to chew on electrical cables.

That's why electrical cables are enclosed in aluminium or PVC conduit in houses.

I have heard tales of cars and pickups being disabled because of rats eating the wiring.

 

I don't know if it's true but I have been told that rats eat wires and cause property destruction because their teeth are constantly growing.

This is similar to claws on cats and dogs... since they are constantly growing, they have to be dealt with on a regular basis.

By chewing on wires, rats get rid of the growing pains and they also keep their teeth in great shape.

[Encid]

22 hours ago, Tarteso said:

Thinking to buy this one ???? 

18.000.- Deliver to Phuket..

25.000.- Deliver to anywhere.
 

 

Check out Solar hot water heater 150 litre. Stainless stee...at 22% off!฿17,950.00 only!Get it on Lazada now! https://s.lazada.co.th/s.SoOQt

Sounds like a much better deal than Boonthavorn even though it is only half the capacity... for most families 150L should suffice. 

[MJCM]

1 hour ago, Encid said:

for most families 150L should suffice

Maybe some clever member knows how to combine 2 units into 1 and thus saving you 150k ????

Edited September 2, 2022 by MJCM

[Crossy]

1 hour ago, MJCM said:

Maybe some clever member knows how to combine 2 units into 1 and thus saving you 150k ????

 

Pipe works quite well ???? 

[MJCM]

14 hours ago, Crossy said:

 

Pipe works quite well ???? 

Only some pipe, would that work because of pressure release etc?

 

And for pipe I hope they use PPR and not PVC ????

[Muhendis]

55 minutes ago, MJCM said:

Only some pipe, would that work because of pressure release etc?

 

And for pipe I hope they use PPR and not PVC ????

Blue PVC pipe comes in two variations. 8 Bar and 13.5 Bar so it's good for domestic cold water

You have to watch the temperature though. PPR is best if the temp. is going to be in the "hot water" range.

Although I've never experienced it myself, apparently PVC joints can fail with hot water whereas PPR is a fuse welded joint and the plastic itself is much more hot water tolerant.

[MJCM]

5 minutes ago, Muhendis said:

Blue PVC pipe comes in two variations. 8 Bar and 13.5 Bar so it's good for domestic cold water

You have to watch the temperature though. PPR is best if the temp. is going to be in the "hot water" range.

Although I've never experienced it myself, apparently PVC joints can fail with hot water whereas PPR is a fuse welded joint and the plastic itself is much more hot water tolerant.

AFAIK Blue PVC is oke with water temperatures up to 65c correct?

[MJCM]

On 9/1/2022 at 4:26 PM, Bandersnatch said:

 

 

 

 

    

Re: I was talking about Pressure because of this Video by @Bandersnatch

[Muhendis]

18 minutes ago, MJCM said:

AFAIK Blue PVC is oke with water temperatures up to 65c correct?

The maximum temperature is 140°F which is 60°C

But specs for the blue pipe are measured at 27°C

As the temperature goes up so the strength goes down.

[Pouatchee]

On 8/31/2022 at 6:35 PM, Bandersnatch said:

I have had solar thermal for 4 years now.

Hi, where did you purchase your system. I am currently building a house and have been looking for a system like yours but it is quite difficult to find.

[Bandersnatch]

9 minutes ago, Pouatchee said:

Hi, where did you purchase your system. I am currently building a house and have been looking for a system like yours but it is quite difficult to find.

I purchased it at a renewable technology expo at  Ruangsangthai Buriram

[sezze]

22 hours ago, Muhendis said:

Blue PVC pipe comes in two variations. 8 Bar and 13.5 Bar so it's good for domestic cold water

You have to watch the temperature though. PPR is best if the temp. is going to be in the "hot water" range.

Although I've never experienced it myself, apparently PVC joints can fail with hot water whereas PPR is a fuse welded joint and the plastic itself is much more hot water tolerant.

I got PPR fast locking , no welding required . Plug in and impossible to remove without breaking it apart ( as family members noticed hahaha) . So far after 10y , not a drop of leakage , while i did have to fix a few standard blue pvc lines .

[Muhendis]

2 hours ago, sezze said:

I got PPR fast locking , no welding required . Plug in and impossible to remove without breaking it apart ( as family members noticed hahaha) . So far after 10y , not a drop of leakage , while i did have to fix a few standard blue pvc lines .

Oh bum. 

That's made my welder redundant I guess.

[Encid]

7 hours ago, sezze said:

I got PPR fast locking , no welding required . Plug in and impossible to remove without breaking it apart ( as family members noticed hahaha) . So far after 10y , not a drop of leakage , while i did have to fix a few standard blue pvc lines .

There is a way to dismantle it if you have the right tool.

This video shows you how.

It would not be easy however trying to dismantle in a fully assembled domestic water piping system.