[saisree]

Originally Posted by sagarpadaki

How different is this compared to conventional solar panel based water heaters?

The below is what I see in the link. What I understood from the installer then was, its more effective and has less maintenance/replacement costs compared to the conventional Solar heater (Panels). It also has a inbuilt heater core, connected to a normal 15 Amp socket which, I never used. Costed me 18K in 2009.

The Venus Vacuum Tube Collector solar water heater is made up of rows of parallel, transparent glass tubes. Each tube consists of a glass outer tube and an inner tube, or absorber, covered with a selective coating that absorbs solar energy well but inhibits radioactive heat loss. The air is withdrawn ("evacuated") from the space between the tubes to form a vacuum, which eliminates conductive and convective heat loss.

The Vacuum tube collector absorbs the heat from the solar radiation & heats up the water stored in the system through the Thermosiphonic effect.

[null]

Solar water heater (flat plate model) is not heating up the water as it should at our place. The hot water flow pressure in the bathroom taps has reduced drastically.

I suspect some blockages in the solar heater (and not the pipes alone as the flow pressure is poor even in the nearest tap few feet below the heater). The panel surface is clean, thanks to the periodic rains. There are no visible signs of damage like leaking etc.

Does anyone know what to check in the heater?
- any ways to flush out the water/dirt/grit? Can it be done by us?
- flushing the tank?
- what else to check?


Anyone tried?

[JMaruru]

Originally Posted by null

Anyone tried?

The solar tank and the piping which carries the water around the panels needs to be cleaned regularly. I get my solar serviced every alternate year and it's been in good shape. During the service they open the joints around the panels and the bottom outlet on the tank and flush all the water out. Lots of accumulated soil/muck would be cleared during this exercise.

You can ask any decent plumber to do this, if NOT for the manufacturer.

[sumathindra]

Found this is the only thread on Solar water heaters and hence decided to resurrect this thread for a critical issue we are facing in our area in Jayanagar 3rd Block Bangalore.

In the last couple of months there has been many thefts of copper installed in the solar heaters installed on terraces. The culprits used to operate during mid nights and recently they are striking during afternoon and evenings as well. While the cops have been informed and not much help, what can be some security measures taken to prevent this.

CCTV's helps identify the culprits however would not deter them. Has anyone in this community faced such issues and what measures were taken to stop them? Any pointers is much appreciated.

[dhruv45in]

Team, I have a query and would like some help to my problem.

I live in the Himalayas and recently got a 300 l solar water heater. I have an automatic pressure pump for the cold water lines which keeps the pressure healthy. Since I have the solar fixed atop the roof, I was expecting enough hydrostatic pressure in the hot water line but to my surprise the pressure is too low and I can’t use shower or other taps as the mixture is not right. I didn’t know and wasn’t guided about the pressurised solar heaters.
So I wanted to know what are my options?can I use another pressure booster pump at the hot water outlet of solar heater? Or is there a better way to boost hot water pressure?

[deep_bang]

Originally Posted by dhruv45in

So I wanted to know what are my options?can I use another pressure booster pump at the hot water outlet of solar heater? Or is there a better way to boost hot water pressure?

If, at the end you want to use a tap that mixes cold and hot, there is never a good way to do that with different pressures on cold and hot lines. You cold even have cold water going into the solar tank because the pressure is too high.

There are 3 options.
1. Go for a pressurised solar tank.
2. Try removing the pressure on cold line and see how it works. If this is livable, this may be a workable arrangement without a lot of changes.
3. Add a booster pump to the solar line but at the same time ensure to have a non return valve on both the cold and hot lines to ensure that water from hot line does not go into the cold and vice versa.

[dhruv45in]

Originally Posted by deep_bang

If, at the end you want to use a tap that mixes cold and hot, there is never a good way to do that with different pressures on cold and hot lines. You cold even have cold water going into the solar tank because the pressure is too high.

There are 3 options.
1. Go for a pressurised solar tank.
2. Try removing the pressure on cold line and see how it works. If this is livable, this may be a workable arrangement without a lot of changes.
3. Add a booster pump to the solar line but at the same time ensure to have a non return valve on both the cold and hot lines to ensure that water from hot line does not go into the cold and vice versa.

Thanks for the reply. If I go with option 3, you mean to say add NRV after the booster pump outlets on both cold and hot water line?

[sagarpadaki]

Originally Posted by dhruv45in

Thanks for the reply. If I go with option 3, you mean to say add NRV after the booster pump outlets on both cold and hot water line?

Before you add booster to solar output ensure that the solar supports booster. Some solar tanks do not support and a booster can damage the tank. This I got to know when I was looking to get a tank replacement for our old solar.

Non return valve after the solar tank output and before the booster pump. Also ensure that the booster pump spec is same on hot and cold lines.

[deep_bang]

Originally Posted by dhruv45in

Thanks for the reply. If I go with option 3, you mean to say add NRV after the booster pump outlets on both cold and hot water line?

Well, what I mentioned is a very non-standard way of solving this problem. So I am not sure if there is a recommended point to add the NRV. My main reason to suggest that was to ensure that hot water does not go into the cold line and vice versa.
The right way to fix this is to have one pressure pump driving the entire cold and hot lines. But this would mean changing the solar water heater to a pressurised one. Since this is expensive, I was suggesting other options(cheaper but may not be optimal).

In case it helps, I have a pressurised solar water heater and had a groundfos pump pressurising the entire system. This did not work during powercuts and also back when I had installed, we had a severe shortage of water. Hence, finally disconnected the pressure pump and running it on a more simple gravity-based system now. Yes - the pressure is lower but can be fixed to some extent with the right low-flow shower heads. Moral of the story is - if possible, keep it simple.