Research of Solar Energy Installations in High-Temperature and Low-Temperature Processes

Solar energy is an important, clean, cheap, and abundantly available renewable energy. It is received on Earth in cyclic, intermittent, and dilute form with very low power density, 0 to 1 kW/m2. Solar energy received on the ground level is affected by atmospheric clarity, degree of latitude, etc. For design purpose, the variation of available solar power, the optimum tilt angle of solar flat plate collectors, and the location and orientation of the heliostats should be calculated. Many renewable energy technologies today are well developed, reliable, and cost competitive with the conventional fuel generators. Solar furnaces (SFs) are primarily used as tools for high-temperature research of materials and processes. In particular, given that higher temperatures are achieved at the focal point of a solar furnace than in an electric arc or oxyacetylene flame, SFs have been used to experiment with using solar radiation to weld metal structures in orbital spaceflight conditions. The welded joints proved to be stronger than the original steel. Under certain conditions (gas atmosphere), welding has also been extended to non-metallic materials (refractory oxides, ceramics, etc.). SFs are also used for melting quartz and other refractories. Even in relatively small SFs with a 2-meter diameter spotlight mirror and a 2.5 x 3-meter heliostat, temperatures of 2000–2600°C are achieved. The most efficient use of solar energy is to heat the refrigerant in solar power plants (SPPs) using solar collectors (SCs), whose efficiency can reach 80% (evacuum tube SCs). An absorption chiller is a compressor-less refrigeration unit that generates cold using hot water, solar energy, steam, or natural gas combustion. This heat is primarily waste heat, which is typically dissipated into the atmosphere through a system of cooling towers.