SolarWater Heaters

HOMES:Solar water heater for cold climates—Freezing protection

By December 12, 2018 No Comments

Our Solar Products are produced according to European EN 12975 standard productions has and it is able to operate under all weather conditions,
our solar manufacturing was awarded the ISO9001, ISO14001, CE certification.

Freeze Protection: Because the heat pipe is located within the evacuated glass tube, brief overnight temperatures as low as -20oC (14oF)
will not cause the heat pipe to freeze.

  • High heat conduction coefficient: is 2000-5000 times of metal materials.
  • High quantity of heat conduction: is 1000times of metal materials.
  • Low temperature difference: less than 4ºC difference in 2 meter long pipe.

Structure and Principle:

At sea level water boils at 100oC (212oF), but if you climb to the top of a mountain the boiling temperature will be less that 100oC (212oF). This is due to the difference in air pressure. Based on this principle of water boiling at a lower temperature with decreased air pressure, by evacuating the heat pipe, we can achieve the same result. The heat pipes used in solar collectors have a boiling point of only 30oC (86oF). So when the heat pipe is heated above 30oC (86oF) the water vaporizes. This vapour rapidly rises to the top of the heat pipe transferring heat. As the heat is lost at the condenser (top),
the vapour condenses to form a liquid (water) and returns to the bottom of the heat pipe to once again repeat the process. When the heat pipe is shaken, the ball of water can be heard rattling inside. Although it is just water, it sounds like a piece of metal rattling inside.

Quality Control:

Often heat pipes use a wick or capillary system to aid the flow of the liquid, but for the heat pipes used in solar collectors no such system is required
as the interior surface of the copper is extremely smooth, allowing efficient flow of the liquid back to the bottom. Also heat pipes are not installed
horizontally. Heat pipes can be designed to transfer heat horizontally, but the cost is much higher.

Freeze Protection:

Even though the heat pipe is a vacuum and the boiling point has been reduced to only 25-30o C (86o F), the freezing point is still the same as water at sea level, 0o C (32o F). Because the heat pipe is located within the evacuated glass tube, brief overnight temperatures as low as -10o C (14o F) will not cause freezing damages Plain water heat pipes will be damaged by repeated freezing, but heat pipes are protected against freeze related
damage.

SW

SW