Gravity fed evacuated tube systems

[hamish]

Who has an evacuated tube system and how do you find it, pros and cons.

[cssolar]

gravity feed swh

Who has an evacuated tube system and how do you find it, pros and cons.

Hi Hamish,

I have been running a direct gravity feed system on my house since 2008 I have found it very good.

Pros

1 low cost
2 plug and play , easy installation
3 water in tube provides extra storage of water
4 vacuum tubes allow the sun to track around the tubular surface
5 in the case of cut water supply, you have stored water in the tank
6 comes in kit form for easy assembly at the point of use


cons
1 some people consider the system to be ugly
2 low water pressure ( i had to use an auto boost pump to get decent pressure for showering )
3 if a tube breaks all water in the tank will be lost ( I have never experienced or seen this happen and have found having a water in tube system no problem )
4 scale build up in tank is higher on a direct system as water is continuously changing
5 if no water is drawn the unit can easily over heat and boil ( recommend covering collector tubes when not in use for a long period )
7 must be mounted above point of use


Hamish the above system is a gravity feed non pressure type, it is different from a pre heat type

The pre heat type has the same non pressure tank and water in the vacuum tubes but it has the advantage of a copper coil heat ex changer

pros

1 can be mounted below the point of use
2 indirect system so little scale build up in the tank
3 mains pressure hot water ( no boost pump required )
4 anti freeze can be added to main tank

cons

1 higher cost than gravity feed system
2 no usable stored water


Cheers Tony

[russ]

Good analysis and post Tony!

[cssolar]

Good analysis and post Tony!

Thanks Russ

Its warming up here now, I guess it is in Turkey too !

I am still experimenting with my water cleaning machine , so far production is quite low

Yesterday I added some salt to the water feed about 5ppt I am interested in seeing how it copes an if it will reduce the salt to a safe level for drinking

Cheers Tony

[russ]

Actually I am in India the past months - back at the same place I spent some 15 years and it is warm - upper 30's every day.

Soon the monsoon starts and the humidity goes through the roof as well.

It will be interesting to see your progress on the water purification scheme.

Russ

Thanks Russ

Its warming up here now, I guess it is in Turkey too !

I am still experimenting with my water cleaning machine , so far production is quite low

Yesterday I added some salt to the water feed about 5ppt I am interested in seeing how it copes an if it will reduce the salt to a safe level for drinking

Cheers Tony

[cssolar]

Actually I am in India the past months - back at the same place I spent some 15 years and it is warm - upper 30's every day.

Soon the monsoon starts and the humidity goes through the roof as well.

It will be interesting to see your progress on the water purification scheme.

Russ

I bet you can get a good curry there !

Just checked my water cleaner , first day running salt water

5 ppt salt water in .05ppt out , I am quite pleased as it is well below the acceptable level for drinking water !

But production is low about 4.5 litres , steam loss is a bit of a problem, I will try and ad some cooling fins to reduce this.

Regards Tony