Evaluation of Energy Efficiency of Solar Roofing Using Mathematical and Experimental Research

A relevant issue today is the principle of energy efficiency and rational use of energy resources. At present, solar heating systems with conventional solar collectors are quite expensive. Given this, we designed and patented a solar roofing, which combines the functions of a solar collector and a metal corrugated part of the pitched roof. The feature of solar roofing is that its heat absorber is made of the corrugated roofing material of the building. This makes it possible to significantly reduce the cost of the solar system, improve its strength and simplify the design.Comprehensive solution of the issues of fixing solar collectors directly to the elements of the roof has broad prospects because, in this case, the possibility of replacing a part of the roof with them can be implemented. This eliminates additional load on the carrying structures and reduces the cost of solar heating in general. We developed a mathematical model of the work of a solar roofing in the heating system, which is a dependence of calculation of heating temperature of the heat carrier in the tank-accumulator on intensity of the heat flow and period of radiation. It was established that at changing incident angles of the heat flow from 90º to 30º, effectiveness of solar roofing reduces insignificantly compared with the flat solar collectors.We improved dependences of change in the efficiency of solar heating systems using a solar roofing on the direction and velocity of the air flow. It is established that energy efficiency of a solar roofing is larger affected by velocity of air flow, while its direction is less important

Study of the Thermal Mode of a Barn for Piglets and a Sow, Created by Combined Heating System

The present research addresses solution to the relevant problem of energy efficient heating supply of pig farms with barns of pigs and a sow by applying combined heating systems based on local heating of places for animal keeping. A physical model is developed, which offered the possibility to carry out a complex of experimental studies on determining temperature mode in the barn for piglets and a sow. We established the patterns of influence of thermal capacity of individual heating devices, in particular the heating panel in the place of sow keeping, as well as the heating mat and the infrared heater, on the thermal condition of specific areas.Assessment of the influence of the main factors of the research on its original characteristics was performed. We obtained the equation for determining relative air temperature in the zone of piglets and sow keeping, which depends on relative height of the operation area at a variable air velocity, as well as on incoming air temperature, influenced by the number of animals and background temperature in the premises. Graphical dependences were constructed and empirical dependences were derived based on the conducted experimental studies that can be used in subsequent engineering calculations.Based on the obtained results, we compiled recommendations on the choice of thermotechnical parameters of heating devices, particularly their geometric dimensions, material and method of location of heating elements

Theoretical and Experimental Analysis of Solar Enclosure as Part of Energy-efficient House

The use of solar energy as a potential alternative source to ensure the heat supply to energy-efficient houses was explored. We have performed preliminary theoretical analysis of energy indicators for the combined heat supplying system when a solar window is used as part of the enclosure for an energy efficient house. In order to enhance operational effectiveness of the studied plant relative to existing solar collectors and to improve it in the structural aspect, the stratification of a heat carrier in the tank-accumulator of the combined heat supply system with a solar window was calculated.The study of operational efficiency of the experimental setup for using solar energy was carried out under the mode of circulation and gravitational motion of the heat carrier by the intensity of radiation of the solar energy simulator on the system of 600 W/m2 and 900 W/m2. Water was used as a heat carrier.We have analyzed changes in temperature of the heat carrier in the solar collector and in the tank-accumulator of the proposed combined solar heat supply system with a solar window as part of the external enclosure of an energy-efficient house.It was established that the heat carrier temperature under the circulation mode reached 26.5 °C. We have also presented comparative field, laboratory, and theoretical calculations of the average temperature of the heat carrier in the tank-accumulator under the mode of the heat carrier gravitation motion under various conditions.Efficiency of the experimental setup was calculated. The dynamics of change in efficiency of the solar heat supply system with a solar window were described. Efficiency was ≈55 % under the mode of heat carrier circulation for heat energy accumulation in the tank-accumulator, depending on heating duration. Under the mode of gravitational motion of the heat carrier, we calculated efficiency for the design of a solar window only, which was 53

Results of Experimental Researches Into Process of Oak Veneer Drying in the Solar Dryer

A new design of solar drying plant with the active solar energy system is developed. It is proposed to use the K1-102 automated control system to diagnose the key parameters of air exchange in the solar dryer and to predict the intensity of heat exchange processes of oak veneer drying. This allows increasing the technological and power efficiency of the process of oak veneer drying in the solar dryer 2 times.The regularities of the influence of the physical parameters of the environment and weather-dependent factors on the heat, mass, and moisture exchange processes of oak veneer drying in the solar dryer are determined. Estimation of energy, kinetic and dynamic parameters of the oak veneer drying process is given. The duration of the drying process in the solar dryer is experimentally determined. Performance characteristics of the drying object are investigated, depending on the set technological tasks (heating or drying) under standard insolation and meteorological conditions.It is found that it is necessary to regulate air exchange, moisture release, rational moist coolant removal, solar energy flow in relation to the predicted changes in the minimum and maximum variation peaks of weather-dependent factors. This is important for intensifying the oak veneer drying processes and reducing the specific power consumption of the drying process due to solar energy.The obtained results can be used in the development and improvement of technical means of oak veneer drying, to improve the technological and power efficiency of the proces