• 18 58mm x 1800mm Vacuum tubes 
• 180 Liter (48 Gallon) Storage Tank with painted galvanized tank 
• Galvanized Stand

Description of Passive Solar Water Heater Application

Passive solar water heaters use vacuum tubes with heat pipes and an attached water tank for direct heating of potable water. Sunlight enters the tubes, converting into heat at ~94% efficiency, and is then carried up through the heat pipe to the manifold which heats the water inside of the attached water tank. Water is supplied at the inlet from city/well water, heated and then fed directly into the hot water plumbing of the building.

This unit includes an electric backup water heating element and a TK-7Y controller. The passive solar water heater controller is used for timing of the backup water heating and display of the tank temperature. Settings on the controller help prevent heating water when hot water will not be needed, such as during 4 in the morning. This gives the user the ability to only use electrical backup heating when it may be needed, thus giving the sun a chance to replenish heat.

Since the tubes are not filled with the water itself, this passive solar water heater is resistant to temporary freezing temperatures. These heaters are very popular for use in southern parts of America. For applications in more northern regions where freezing is common, it is best to utilize split solar water heater systems.

Because the condensers of the heat pipes are submerged into the water within the tank, the heat transfer process of the passive solar water heater is more efficient than in a split system. We estimate that the passive heaters peak at about 55% efficiency based on gross area of the heater (not including the tank surface area) while the solar collectors of split systems peak at about 42% efficiency based on gross area.

Which system you choose depends on your location and preference. In the summer, the passive heater will certainly be more efficient. However, in the winter, since the tank is outside and exposed to the cold, there will be a lot more heat loss than in a split system, and the risk of freezing on the water pipes and tank would be an issue in colder climates to watch out for.

The standard passive solar water heaters with the painted galvanized outer shell and galvanized stand are ideal for most applications. The stainless steel passive system may be used in more corrosive environments (installed near a natural water body, especially with salt content) or simply for the more aesthetically pleasing metallic look. Both units perform and operate exactly the same otherwise.

Pressurized Passive Solar Water Heater Sizing Chart

Manufacturer's Warranty Period:
All of our solar products come with a manufacturer's warranty. A manufacturer warranty covers materials defective due to the manufacturing process. If a manufacturing defect is discovered during the manufacturer's warranty period, the item may be returned to Duda Energy for repair or a replacement. Only materials found defective due to manufacturing will be replaced under the warranty. The warranty does not cover natural phenomenons such as corrosion.

The manufacturer's warranty period does not designate the expected lifetime for a material, unit or device. It only applies a limited time period in which defects due to manufacturing may be eligible for a claim.

Solar Water Heater Warranty Period: 3 Years

How it Works: