Swimming Pool Refurbishment – Sizing And Orientation
A typical solar pool heater consists of a collector that is made of plastic panels. The panels have tubes (called headers) on the top and bottom of the panel that allow water to flow into and out of the plastic panel. The headers are connected by many small tubes through which water flows and gets heated by the sun. The size of a collector needed for a swimming pool depends on several factors including the size of the pool, climate, desired water temperature, wind conditions, how shaded the pool is and how often the pool will be used. Normally, the total area (square footage) of the solar collector will be at least half of the pool surface area. For example, if the pool covers 500 square feet, the collectors should be at least 250 square feet.
Collectors should face south and be tilted at an angle equal to the latitude of the pool’s location minus 10 to 15 degrees. If this is not possible and the collectors must be laid flat or must face west, the collector will not get as much sunlight. In this case, a larger collector area will be needed to make up for the decrease in collector efficiency resulting from less sunlight. Pool collectors can either be mounted on the roof of a building or mounted on a frame on the ground near the pool. Where the collectors get placed depends on how much space is available and how much sunlight shines on the space.
Pools lose heat through convection, evaporation and radiation from the pool surface, and by conduction from the sides or walls of the pool. The amount of heat that is lost depends on many factors, such as the water temperature, air temperature, humidity, pressure, and wind across the pool surface. On average, outdoor pools lose almost 90% of their heat from the water surface: 70% by convection and evaporation, which are related, and 20% by radiation to the sky. About 10% is lost by conduction from the sides and bottom.
The best way to prevent the heat loss from evaporation is with a plastic pool cover. A pool cover costs about 50 cents per square foot and can last up to five years. A clear or translucent cover works better than a dark or opaque cover because it allows sunshine to warm the pool through the day. Placing a cover over the pool can raise water temperatures between 5ËšF and 10ËšF. The actual amount depends on the type of cover, when and how long it is used during the day, and how much sunlight the pool gets. Although covering and uncovering the pool requires more work, covers are an inexpensive way to keep the pool water warm and reduce the amount of water lost to evaporation.
Care of the Pool Heater
Most swimming pools have filtering systems to maintain good water quality in the pool. The plumbing of a solar pool heating system is connected to the pool’s existing filter system. Special equipment controls the waterflow between the pump, the filter, the solar collector and the pool.
If solar collectors are being added to an existing pool, a new circulation pump may need to be added because the existing pump may be too small to move the water through the collectors. In parts of Texas where freezing temperatures are common, special equipment should be installed to allow all water to drain when the system is turned off so the pipes will not freeze and become damaged.