How Solar Water Heating Works
Solar Heating Process Outline:
1. Solar Energy Absorption: Solar energy is absorbed by each tube and converted into thermal energy
2. Solar Thermal Energy Transfer: The thermal energy is then transferred from the glass tube to the heat pipe by a heat fin via conduction
3. Solar Thermal Energy Storage: The thermal energy is then transferred from the solar heating panel to a storage tank by a heating fluid that is pumped through the panel
Solar Heating Process In Detail:
1. Solar Energy Absorption: Solar energy is collected and converted into heat
The solar collector which is mounted on a roof or on the ground - with an angled bracket - is responsible for collecting solar energy and converting it into heat in a matter of minutes. As the sunlight passes through each evacuated tube, which is lined with an absorbing film, it is converted into heat and conducted into a heat pipe which transfers the heat into a copper manifold.
Each evacuated tube is enveloped with a layer of vacuum between the 2 glass walls which prevents heat from escaping into the atmosphere. This guarantees an optimum high heat transfer rate. This is similar to a flask or double glazed window.
2. Solar Thermal Energy Transfer: Circulating fluids like water or glycol transfer the heat from the manifold into a heat exchanger tank where water is heated.
In the heat exchanger tank the circulating fluid (or heating fluid) is circulated through an internal coil heat exchanger where its heat is given off to the water inside the tank. The fluid then continues to circulate back up to the collector where it is heated again. In the case of pool or hot tub heating the heated fluid passes into a shell and tube heat exchanger where it gives off heat to the pool water. In the case of infloor heating, the heat exchanger tank is replaced with a double coil heat exchanger tank where the bottom coil is heated by the heating fluid and the top coil heats the infloor heating water.
3. Solar Thermal Energy Storage: The heated water is stored
The heated water in the heat exchanger tank is heated and stored. When there is a demand for hot water the solar heated water flows into the existing heating tank where it requires little or no additional heating. When hot water is drawn from the top of the heat exchanger tank, cold water make-up enters the bottom of the tank to be heated by solar energy. This allows for the storage of twice the volume of hot water than the existing setup with one hot water heater.
Solar Pool Heating Process:
Solar pool heating works in a similar fashion however the heating fluid transfers its heat to the pool water via a heat exchanger. The heated pool water is stored in the pool itself. Cold pool water is constantly drawn from the pool; heated in the heat exchanger and returned to the pool as hot water. The use of a solar blanket is beneficial because it allows the pool to retain its heat at night.
Learn more about solar domestic hot water and solar pool heating and solar radiant heating