the geometry of a collector is one of the important factors that can increase the incident radiation on the collector surface. in the present study, the incident radiation for a stationary collector with cone geometry, i.e. a conical collector, is theoretically and experimentally investigated. this type of collector is always stable and does not need a fixture to install. moreover, it has a sym...

nowadays two important discussions in academic parties all over the world are energy crisis and environment crisis. one of the strategies to deal with these crisises is using clean, renewable and domestic energy sources. one of the best renewable energies that can be used in different scales is solar energy. in iran which is considered among the greatest countries that receive huge amount of so...

Solar water heaters are good tools for saving fuel. The main component of these water heaters is collectors, which are responsible for absorbing solar energy and transferring it to the working fluid with the least heat dissipation. The present study is an experimental study of the performance of the solar semispherical collector with 1 m2 of absorber area at different volumetric flow...

Parabolic trough solar technology is the most proven and lowest cost large-scale solar power technology available today, primarily because of the nine large commercial-scale solar power plants that are operating in the California Mojave Desert. However, no new plants have been built during the past ten years because the cost of power from these plants is more expensive than power from conventio...

This paper explores the benefits and drawbacks of using carbon dioxide in solar thermal systems at medium and high operating temperatures. For medium temperatures, application of CO2 in non-imaging-optics based compound parabolic concentrators (CPC) combined with evacuated-tube collectors is studied. These collectors have been shown to obtain efficiencies higher than 40% operating at around 200...

For a solar thermal system, increasing the heat transfer area can increase the output temperature of the system. However, this approach leads to a bigger and bulkier collector. It will then increase the cost and energy needed to manufacture the solar collector. This study is carried out to estimate the potential to design a smaller solar collector that can produce the same desired output temper...

Among the renewable sources of energy, solar energy offers a practical solution for the energy problem which is clouding the prospects of mankind. The present paper deals with the experimental investigation of parameters of a solar parabolic trough in winter conditions and to obtain optimum process parameters by Grey Relational Analysis. The experiments were planned using Taguchi’s L9 orthogona...

The possibility of using flat plate collector in northern parts of Iran specially city of Rasht has been investigated in this paper. According to the high humidity in the northern parts of this country, diffuse radiation plays a more important role than direct radiation. This fact can change the results of delivered solar energy and the best tilt angle of the collector compared to the sunny cen...