Design and principle of operation of non-pressure water heater
Design:
The solar collector consists of vacuum tubes made of borosilicate glass. High operational safety of borosilicate glass has been achieved thanks to the use of an appropriate mix of SiO2 and B2O3 oxides, which results that the product has high chemical resistance as well as extraordinary purity and uniformity. Borosilicate glass is environment-friendly and can be recycled many times. The process of thermal annealing (hardening) with the low thermal expansion typical for borosilicate glass gives it a particularly high resistance to changes of temperature in comparison to standard glass. Tubes are resistant to hail size up to 25 mm. The use of tubes with a diameter of 47 mm and 58 mm allows concentric placement of one inside the other. The air between the pipes is pumped out, and the pipes are welded together. Solar radiation on the absorber located on the inner tube is converted into thermal energy and causes heating of the interior of the tube. The vacuum between the tubes is an excellent insulator and prevents heat loss. The tank is made of SUS 304-2B stainless steel and is insulated with polyurethane foam with a thickness of at least 50mm.
JNHX series models have a copper coil installed inside the tank that can be directly connected to the water supply. A small assistant tank can be installed in the tank for automatic water topping up. When the tank is full, the intake valve is automatically closed with the use of the float.
Principle of operation:
There is water in both in the tank and the tubes. Under the influence of sunlight, the water in the tubes heats up. Thanks to convective movements, it goes up to the tank. Water circulates continuously between the tank with water and the vacuum tubes, which causes a constant increase of temperature. of water. High efficiency of the collector results from the ability to absorb diffused radiation (for example, on cloudy days) and maximum reduction of heat loss. The collector works great also in winter. It obtains energy not only from direct sunlight but also from light reflected from snow.
The small equalizing tank installed is used for automatic topping up of water in the tank directly from the water supply network. The JNHX series systems have a copper coil mounted inside the tank and can be directly connected to the water supply. In this case, the water in the tank is not used; it only serves as a heat buffer for water flowing under pressure in the coil. The advantage of this solution is the possibility of obtaining domestic hot water under higher pressure. There is no need for gravity drainage or the use of pumps. Instead of water, there may be a glycol solution in the tank, which can circulate additionally in the central heating system.
The system does not require pumps or controllers for proper operation, which makes it very reliable. Thanks to the open circuit, even boiling water does not increase the pressure inside the tank. Thanks to this, the system is trouble-free and safe.
Disadvantages:
-The higher efficiency of the vacuum collector in comparison to a standard, flat collector.
- Simple design, low failure rate - service life of tubes over 15 years.
- Direct connection of the collector to the tank (no heat loss).
- Excellent insulation of the tank (daily loss of water temperature from 6 to 10 degrees C).
- No need to use pumps or controllers.
- Simple installation that does not require modification of the current system.
- Damage to the vacuum pipe from the "heat pipe" does not turn off the entire system, but only reduces the efficiency of the collector.
- Easy servicing and self installation possible.