Determine frequency of use—when will your system be used and how often? This is often overlooked when designing a system. Frequency will determine the type of collectors used, solar loop type, and storage tank size. If you want year-round domestic water heating, then this will not be a concern. If you want to heat water for a summer camp, then you know the load will be pretty constant throughout the day for showers and food service—components for warm weather and minimal storage are called for. If you want space heating, maximize your system’s winter performance and incorporate summer heat-dumping capability.
Measure the space available for mechanical equipment. Solar thermal systems require tanks, pumps, controllers, and heat exchangers. In most cases, the building’s mechanical room can house the solar equipment. If that space is already full, you will have to be creative. Is there a closet or corner of another room that can be used? If you live in the deep South, what about the attic or crawl space? Can an outdoor shed be insulated and made into a remote mechanical room? Other options are to use a one-tank system with an integrated backup electric element or a single storage tank with a tankless backup heater that can be wall-mounted.
For solar water-heating systems, you will need room for the existing water heater and the new solar tank. If you plan on replacing an old tank-type water heater with a solar tank with an integrated heat source, then no extra space will be needed.
For space-heating systems, the floor space needed for equipment depends on how the solar heat will be stored. The size of storage tank will determine the space needed. If the slab of a radiant floor system is the storage medium, no space needs to be set aside.
Pool systems do not have separate storage, as the pool serves as the storage. All of these systems will need pumps, controls, and, possibly, small drainback or expansion tanks. These components are usually mounted on a wall (even above the solar tank), so they normally don’t take up much space. Always leave enough room for future servicing.
Kurt Koegel has more than 25 years of experience in the plumbing and heating industry, and holds a master plumber’s license in multiple states. He is one of the first 10 professionals in the nation to be certified through the North American Board of Certified Energy Practitioners (NABCEP) as a certified solar heating installer.