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The use of air curtains in livestock premises is aimed at limiting the amount of cold air entering through the open gate opening and heating it. Recommendations for selection and calculation methods for air curtains for cattle breeding farm premises are given, taking into account the influence of wind load. The proposed method makes it possible to calculate the thermal and energy parameters of air curtains, taking into account the variability of the climatic factors impact (wind speed and direction). The aerodynamic coefficients of the cowshed building, taking into account wind directions, were determined to calculate the amount of air entering through the gate opening protected by an air curtain. Formulas for calculating heat losses through an opening protected by an air curtain are given. The procedure for calculating the parameters is proposed and the requirements for air curtains for cattle breeding livestock premises are formulated.

The article considers the possibility of using thermoelectric dehumidifiers in microclimate systems for livestock premises. The advantages of dehumidifiers based on thermoelectric modules in comparison with compressor and adsorption units are shown. A block diagram of a thermoelectric dehumidifier designed to operate in agricultural production conditions is presented. The heat exchangers of the cold and hot circuits, as well as the electric fan, form a single structure and are installed in premises in which it is necessary to dehumidify the air. The dehumidification process in a thermoelectric unit is shown in the I-d diagram of humid air. A method for calculating a standard-sized range of thermoelectric units for air cooling (dehumidification) in agricultural premises has been developed. Provisions presented the method that allows determining the thermal and structural parameters of the main components when designing a thermoelectric unit.

An analysis of scientific studies has been carried out, which presents thermoelectric technologies based on solar energy that can satisfy not only the need for electricity generation, but also contribute to energy saving and environmental protection. The results of theoretical and experimental studies on the development of power supply systems based on thermoelectric generators in combination with photovoltaic panels, solar concentrators and heat pipes are also presented, allowing us to conclude that the creation of solar thermoelectric generators is relevant. The authors have developed a design and presented a description of the power supply installation operation with a solar thermoelectric generator and heat pipes transmitting thermal energy from a solar concentrator through a solid-state thermal storage to a thermoelectric generator. Expressions are given for calculating the main thermal characteristics of the elements of the proposed installation with a solar thermoelectric generator (solar concentrator and solid-state thermal storage), as well as the efficiency factor and output electric power of the thermoelectric generator.

Theoretical studies of the thermal state of heat storage elements with air channels of various shapes in the modes of charging and heat output of the electric thermal storage (ETS) are carried out. The mathematical model of heat exchange processes adapted to the operating modes of the ETS is presented. The change in the average heat transfer coefficient in the air channels in the conditions of natural and forced convection in the modes of charging and heat output ETS, and the heat flux density in the mode of charging of the ETS from a tubular electric heating element (TEH) for heat storage elements with channels of a slit and round shape are shown. The temperature distribution in heat storage elements made of chamotte and magnesite with slit-shaped (standard design) and round shape channels is obtained. As a result of the studies carried out, the temperature change and the dynamics of heat transfer in the air channels of heat storage elements made of various types of thermal storage material (TSM) in the modes of charging and heat output of the ETS were analyzed. The conclusion is made about the efficiency of using heat storage elements made of chamotte with round-shaped channels in the ETS.

Recommendations on the selection of air curtains and the calculation of their parameters for livestock premises in cattle management farms are made. The air curtain functioning principle is analyzed from the air jet theory point of view. The block diagram and modular design of air curtains with a variable air jet direction vector and with controlled slit width are designed. Laboratory tests of the newly designed air curtain structure are performed in accordance with the microclimate requirements for the cattle management farm premises. Based on the experimental results, the major air curtain parameters are calculated for the range from 10° to 60° of angle α between the direction of the air jet outward from the air curtain slit and aperture plane, and for the air curtain slit width b0 in the range from 0.05 m to 0.15 m with the account of the wind speed Vw variations. Calculated values for amounts of energy that have to be consumed to ensure the required air jet velocity, in the output from the air curtain, and those for the quantity of thermal energy required to heat the air supplied to the air curtain, depending on the angle α and on the slit width b0, can be helpful for selecting the power capacity of both the air curtain fan and electric heater. A block diagram of the air curtain control for cattle management farm premises is designed, enabling automatic control of the airflow rate, the angle of the air jet output from the air curtain slit, and the temperature of the heated air supplied to the air curtain, considering particular climate conditions. According to the preliminary estimate, applications of the newly designed air curtain will make it possible to reduce the energy consumed to maintain the required microclimate conditions in cattle management premises by 10% to 15% in the cold period. [ABSTRACT FROM AUTHOR]