ISSN 0003-701X, Applied Solar Energy, 2014, Vol. 50, No. 3, pp. 138–142. © Allerton Press, Inc., 2014. Original Russian Text © Z.S. Iskandarov, A.S. Halimov, 2014, published in Geliotekhnika, 2014, No. 3, pp. 17–22. 138 1 The heat-engineering calculations in solar-fuel installations of the concerned type lies in defining the quantity of additional energy generated in an air chan- nel formed between the blackened surface of the dry- ing chamber wall and transparent insulation, which, at the same time, serves as a function of the solar air heater [1]. Incident of the heat on a heat exchange sur- face of a heat receiver (absorbing panel) takes place from two sides: as results of absorbing of solar radiation and heat transfer through walls of the drying chamber [1, 2]. As it is known that, the unsteady conductive heat transfer in the cylindrical coordinates is expressed as the following: (1) where r is the radius of the cylindrical drying chamber, m; is the heat generated in the unit volume of the drying chamber material, W/m 3 ; k is thermal conduc- tivity of the drying chamber material, W/m °C; z is the height of the drying chamber (here and below, it will be denoted by L), m; α is the thermal diffusivity of the drying chamber material, m 2 /s; ϕ is the polar angle of the point the element; and t is time, s. If one takes into account that the wall thickness of the drying chamber is δ = r c – r i , then the thermal resistance of the wall of the drying chamber takes the following form: (2) 1 The article was translated by the authors. ∂ 2 T ∂ r 2 ------- 1 r - ∂ T ∂ r ----- 1 r 2 -- ∂ 2 T ∂ϕ 2 ------- ∂ 2 T ∂ z 2 ------- q · k - + + + + 1 α -- ∂ T ∂ t ----- , = q · R i r c r i -- ln 2 π kL ---------- , = where L is height of drying chamber, m; r c is the radius of the section of the cylindrical drying chamber; and r i is inner section radius of the drying chamber, m. Therefore, if the drying chamber is in the convec- tion with some environment, then the thermal resis- tance of the chamber is defined with the following: (3) where A i and A o are the areas of the inner and outer surfaces of the drying chamber, respectively, and h i and h o are the heat transfer coefficients on the inner and outer surfaces of the cylindrical drying chamber, respectively [5]. Therefore, the thermal balance equation for the vertical cylindrical drying chamber (Fig. 1) is express- ing as follows: (4) where and are the flow rates of the drying agent at the inlet and outlet in the drying chamber, respec- tively; c p and T 1 are the specific heat capacity and tem- perature of the drying agent at the inlet; T 2 is the tem- perature of the heated air flow by the heating coil; q ir is the incident solar radiation intensity on the surface of transparent cover; A cs is the minimal surface area of the transparent cover where solar radiation falls; R 2 is the thermal resistance of the transparent cover mate- rial; T 3 is the temperature of the air layer formed between the drying chamber and transparent cover; R ic 1 h i A i ------- r c r i -- ln 2 π kL ---------- 1 h o A o -------- , + + = m · 1 c p T 1 T 2 – ( ) q ir A cs + T 3 T a – R 2 ------------- = + q ev A ps m · 2 c p T 3 T a – ( ) , + m · 1 m · 2 Numerical Calculation of the Useful Capacity Obtained from Regenerating an Exhaust Drying Agent in a Solar-Fuel Drying Installation 1 Z. S. Iskandarov a and A. S. Halimov b, * a Tashkent State Agrarian University, Tashkent, Uzbekistan b Physical-Technical Institute SPA Physics-Sun, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan *e-mail: halimov@uzsci.net Received May 15, 2013 Abstract—In the current paper, the numerical calculation of useful power received from the regeneration of the exhaust drying agent in a solar-fuel drying installation is presented. The useful power of solar radiation is defined at the given values of the environment. DOI: 10.3103/S0003701X14030050 SOLAR POWER PLANTS AND THEIR APPLICATION