What type of passive solar water heating systems are available?
Passive solar water heating systems are typically less expensive than active systems, but they’re usually not as efficient. However, passive systems can be more reliable and may last longer. There are two basic types of passive systems: • Integral collector-storage passive systems These work best in areas where temperatures rarely fall below freezing. They also work well in households with significant daytime and evening hot-water needs. • Thermosyphon systems Water flows through the system when warm water rises as cooler water sinks. The collector must be installed below the storage tank so that warm water will rise into the tank. These systems are reliable, but contractors must pay careful attention to the roof design because of the heavy storage tank. They are usually more expensive than integral collector-storage passive systems.
