1. Does the solar water heater work in cloudy days?

The solar water heater works in cloudy days but by half of its work in sunny days.

2. Does the solar water heater help in heating?

Never, solar water heater is designed to provide us with hot water, and when there is an urgent need to use solar water heater in heating, it is possible to design such a system which needs many evacuated tubes with high price, this design occupied half of the roof space and it saves only 50% of heating needs.

3. Can we have hot water in cold weather?

The modern solar water heater with evacuated tubes works in cold weather, because the evacuation of the tubes doesn’t allow any heat loss, and it can heat water under 0 degree if it‘s sunny.

4. Why the evacuated tubes?

Due to the tabular shape of the evacuated tubes, the sun is always perpendicular to the surface of the glass for most of the day. Since air is evacuated from the glass tubes to form a vacuum, it reduces the heat loss from the tube. This means that wind and colder temperatures have less effect on the collector’s efficiency.

5. What is the needed time for heating?

One hour sunshine is enough to raise the temperature for bathing, and since the storage tank is big so hot water will be available for the whole day.

6. What is the temperature average of the water in summer and winter?

In average, each tube 58×1800 heats 10 liters of water all the year by 60.

7. Is the evacuated tube break-resistant?

Yes, the evacuated tubes are made of beriks which is heat-resistant and can resist hailstones up to 2.5 cm diameter.

8. What is the frost effect?

The evacuated tube isn’t affected by frost, because the temperature will not be below the inlet cold water temperature of the storage tank, which is not below 10 degrees.

9. What is the calcination effect on the system?

The calcinations effect is little on the evacuated tubes since the lime doesn’t precipitate on glass, so it doesn’t block, and the lime remains wet salt and it is easy to remove.

10. What is the requested maintenance?

The surface of the evacuated tubes needs to be cleaned from dust by sponge and water, and the system needs inner maintenance once every 2-3 years to remove the lime granule inside the solar water heater, it is very easy and doesn’t need any chemical material.

11. Is there any heat loss during night time?

The hot water storage tank in solar water heater is insulated by a thermal installation layer 5 cm thickness and it saves hot water for three days.

12. Is it possible to install solar water heater on an occupied roof?

Yes, the evacuated tube solar water heater takes less than 40% of the roof space and it can be installed on the cold water storage tank by using digital controller.

13. What are the advantages of the controller?

The controller displays the temperature and the level of the water in the storage tank, and it controls water refill to insure best performance of the system; and it prevents the filling during using the system so that the water temperature doesn’t change.

14. What are the advantages of the sub-tank?

It decreases the pressure on the system and insures not to mix cold water with hot water during the usage.