Solar Hot Water Systems and Materials of Construction :: essays research papers

The visibles utilize in solar hot urine systems must be cautiously chosen to ensure that the unit will be efficient just now also affordable. The efficiency of the conversion of sunlight capacity to heat energy of the water depends on the temporals of construction and the efficiency of heat send of the materials. solar hot water systems use the processes of conduction to switch the heat thoughtless from the sun to the water and convection to move water by means of their structure. This assignment discusses the materials utilize in construction of solar hot water systems and their heat transfer properties.2.0 ConductionConduction is the process of transferring energy through a material from one point to an different. Conductivity (k) is the rate at which the energy is transferred and its units ar Watts per metre Kelvin or (W/mK). The higher(prenominal) the rate of conduction the fast-breaking energy is transferred through the material. Conduction can occur in devil dif ferent ways in solids the first is by crystal shaking waves (phonons) where particles of high kinetic energy vibrate rapidly and bump into other particles to transfer energy from one point to another. The second way is by delocalised electrons or free moving electrons which transfer energy throughout materials some(prenominal) better than atoms do, as their energy to mass ratio is much higher than that of atoms. This allows the electrons to travel much faster throughout a substance and transfer energy faster. For a material to be a good managing director of kinetic or electrical energy it requires both methods of conduction, which is found in metals and some other materials (i.e. graphite). The conductivity of a solar hot water systems materials are important ie. adequate insulation is requisite to prevent energy being lost to the units surroundings. Materials for the pipes should not resist the transfer of thermal and kinetic energy being passed through the pipes to the water i n the collector panel (shown in Fig 1.). The conductivity (k) of a material can be described by the followers equation. The contribution of ke increases with free electron concentration. Copper is an abundant, cheap metal with peachy thermal and electrical conductivity. It is strong, malleable and ductile making it an ideal material for water pipes. Copper has a thermal conductivity (k) value of 398 W/mK, which is below silvers thermal conductivity of 428 W/mK provided still much larger than other metals such as aluminium (247 W/mK) or steel (60 W/mK).