A model for solar-hydrogen energy system for Saudi Arabia has been developed by obtaining relationships for and between main energy and energy-related parameters. The parameters’ magnitude and trends with and without hydrogen introduction have been investigated over a period of time. The results indicate that the oil resources of Saudi Arabia would not be enough to meet the domestic and export markets starting in three to four decades. The results also show that adopting the solar-hydrogen energy system would extend the availability of oil resources, reduce pollution, and establish a permanent energy system for Saudi Arabia. They also indicate that Saudi Arabia could become an exporter of hydrogen forever.

One of the reasons for the high cost of electricity generated by statically located solar power plants is the low efficiency of photoelectric converters. Using high-precision solar tracking system will solve this problem. The paper provides a detailed description of the developed modernized structure of an autonomous solar power station with statically and dynamically located modules of solar batteries and a physical model of an automated dual-axis solar tracker. The presented development allows us to increase energy efficiency of solar batteries by precision pointing dynamically located solar modules on the Sun in two coordinates (azimuth and declination angle) during the day. In addition, it is shown that another feature of this photovoltaic system is that statically and dynamically located photoelectric modules are equipped with two types of solar cells – monocrystalline and polycrystalline that leads to an additional gain in the generation of electrical power regardless of the clouds. The ways of increasing the reliability of the autonomous solar power plant operation are mentioned. We have considered the solar tracking systems in the Russian Federation (Orenburg, Tomsk, Chelyabinsk regions) and abroad (United States of America, India, Iran, Turkey, Taiwan), and have justified the necessity of using photovoltaic systems with solar trackers. Moreover, we have successfully tested the developed autonomous solar power plant; the essence of the tests is in an experimental comparison of power generation using statically and dynamically located solar cell modules. The results of the experiments have showed that the use of a solar module with a precision dual-axis solar tracking system, in comparison with a statically located module, makes it possible to increase the efficiency of a photovoltaic installation by 50 %. Thus, experimental evidence of the effectiveness of the automate d tracking system application has been obtained. The work can be useful in the design of energy-efficient photovoltaic installations with the solar tracking system.

The paper deals with the question concerning the increase in buildings and structures energy efficiency and environmental safety at the construction and installation of engineering systems with financial constraints. We suggest solving this problem with low-cost method of solar radiation utilization which implies the passive thermal energy transformation into external fencing structures. In spite of the economic expedience of such heating systems, there is an opinion that they are suitable only for climatic conditions characterized by a mild heating period due to low efficiency indicators in comparison with the active solar power plant. As regards this, the paper analyzes the well-known and new building translucent, absorbing, accumulating and insulating materials along with the possibilities to create the multifunctional external fences that can expand the geography of the use of passive systems. We have studied the nonstationary thermal processes arising in multilayer external fences of buildings in order to solve the problems of effective solar radiation utilization by facade integrated panels. The analysis of mathematical methods has shown that theory of thermal waves should be used to describe the diurnal temperature changes inside building structures. The principle of temperature frequency superposition principle has made it possible to calculate the heat transfer in multilayer external panes. In Voronezh region climatic conditions (52º), we have evaluated the solar radiation effect on a two-layer and a four-layer structure consisting of a glass unit, an air layer, reinforced concrete and heater, protected from the outside by double-glass unit. In January at temperature -24 °C of the coldest fiveday period, the average daily heat losses through the surface area of 1 m2 of the two-layer outer wall are 6 W / m2 , and under the same weather conditions an average heat flux through the surface area of 1 m2 of the four-layer solar panel is of 36.3 W / m2 ; the maximum values of the heat flux are achieved in 18 hours. The presented data confirm the expedience of passive solar panels use in case of low temperatures during the cold period of a year. Moreover, considering the facade glazing trends and low cost of the passive solar panels in contrast with the active solar systems, we concluded that they should be used for increase in energy efficient of buildings.

The paper deals with the variants of the design of free flow high-speed orthogonal aggregates (VAWT-USA terminology) that convert the energy of currents in conditions when the turbine dimensions are much smaller than the depth and width of the flow. It is established that the considered turbines of large length can have the greatest efficiency in variants with one balanced blade when the blade chord is approximately equal to the turbine radius and is deployed by 3-5 degrees (the blade sock outwards from the track). The optimal rotation speed in this case is about 4 times higher than the flow velocity, and when a constant speed of rotation, the maximum power on the turbine shaft is achieved at a flow velocity close to the blade speed. A balanced turbine with two blades and the same solidity (the chord of the blade is half of the radius) has approximately the same efficiency but with the speed of the blades is about 2.5 times higher than the flow velocity on the upstream of the turbine. Moreover, the paper notes the possibility of a noticeable increase in the efficiency of turbines by optimizing the rotation of the blades on the track and increasing the relative diameter of the turbine (D/L >5).