solar water heating system

タイトルまたは説明

This is a example of solar water heating system, which is intalled in China, providing hot water for a hospital.

It composed of solar collector, big tank, control station, circulation pump, etc.

It has about **0pcs solar collectors.

System design requirements

The type, complexity, and size of a solar water heating system is mostly determined by:

• The temperature and amount of the water required from the system.
• Changes in ambient temperature and solar radiation between summer and winter.
• The changes in ambient temperature during the day-night cycle.
• The possibility of the potable water or collector fluid overheating.
• The possibility of the potable water or collector fluid freezing.

The minimum requirements of the system are typically determined by the amount or temperature of hot water required during winter, when a system's output and incoming water temperature are typically at their lowest. The maximum output of the system is determined by the need to prevent the water in the system from becoming too hot or, in the systems that overheating is avoided, the desire to waste money on unneeded components.

Freeze protection measures prevent damage to the system due to the expansion of freezing transfer fluid. Drainback systems drain the transfer fluid from the system when the pump stops. Many indirect systems use antifreeze (e.g. propylene glycol) in the heat transfer fluid.

In some direct systems, the collectors can be manually drained when freezing is expected. This approach is common in climates where freezing temperatures do not occur often, but is somewhat unreliable since the operator can forget to drain the system. Other direct systems use freeze-tolerant collectors made with flexible polymers such as silicone rubber.

When no hot water has been used for a day or two, the fluid in the collectors and storage can reach very high temperatures in all systems except for those of the drainback variety. When the storage tank in a drainback system reaches its desired temperature, the pumps are shut off, putting an end to the heating process and thus preventing the storage tank from overheating.

One method of providing over heat protection is to dump the heat into a hot tub.

Some active systems deliberately cool the water in the storage tank by circulating hot water through the collector at times when there is little sunlight or at night, causing increased heat loss. This is particularly ineffective in systems that use evacuated tube collectors, due to their superior insulation. No matter the collector type, however, they can still overheat and ultimately rely on the operation of T&P valve.