A combined energy–saving heat supply system was proposed that included a combined ETS unit and a ceiling fan, and provided the normative air parameters in a livestock room, with an air temperature of −17 °C and air relative humidity (ARH) of −75%. A heat supply system of a preventive maintenance premises for calves was chosen as the subject of the study. Comparative analysis of the temperature and ARH distribution with height in the preventive maintenance premises, was carried out, with and without a ceiling fan. The study showed that, during the heating period, application of the ceiling fans helped to raise the air temperature and to reduce ARH, in the areas where young stock is located, in accordance with the normative indicators. The energy-saving effect was achieved by supplying warmer ventilation air, which accumulated in the upper zone of the premises from the ceiling fan to the locations of the animals. At the same time, there was a decrease in the consumption of electric energy for the heat supply system of up to 14%.
The article considers the calculation of the main design parameters of a geothermal air cooling system in livestock premises, which, unlike traditional systems, do not use fossil fuels to generate heat. They simply take energy from the soil, while, as a rule, electricity is used only for the operation of fans, compressors and pumps. The purpose of the study is to reduce energy consumption when creating the technologically necessary temperature and humidity conditions in premises by using the cold of the earth’s strata. The calculation of the heat exchanger installed inside the livestock premises is reduced to the choice of design and energy parameters of the surface heat exchanger of the cooling unit, as well as to the determination of the flow rate of water passing through the heat exchanger. Water cooling is done in a heat exchanger buried vertically in the soil (the so-called probe). The probe is a plastic pipe lowered into the well and filled with a special filling with good thermal conductivity. The article presents the calculation of the probe length, since this parameter of the heat exchanger-probe is the main parameter of the installation.
Calculated and experimental studies of thermal processes and the efficiency of heat storage of solid thermal storage materials in an electric thermal storage (ETS) were carried out. Changes in the thermo physical properties of selected thermal storage materials depending on temperature are analyzed. The specific heat storage capacity in the temperature range from 50 °C to 650 °C of such materials as magnesite, chamotte, dinas, corundum was estimated. The research was carried out on an electric thermal storage with an electric power of 2.4 kW with heat storage elements made of magnesite. The temperature distribution is obtained in the heat storage element, as well as in the wall of the air channels of the heat storage elements. Measurements of the temperature of the heated air in the channels of heat storage elements and at the exit from the ETS were carried out. Temperature measurements were carried out with chromel-alumel thermocouples in a ceramic shell and chromel-kopel in a heat-resistant fabric cover. As a result of experimental studies, the temperature distribution in the heat storage elements of ETS is obtained. Based on these data it was calculated the amount of stored heat by heat storage elements of ETS for the complete cycle of its operation.
The use of air heat curtains allows you to limit the amount of cold air incoming the room through open gates or doors, as well as to heat it up. The article considers the influence of air heat curtains on the energy balance of livestock premises. The calculation method is presented and the main aerodynamic characteristics of an air curtain installed in a calf house for 50 animals are substantiated. The main heat and power and structural parameters of the air curtain have been determined. On the basis of the heat balance of the calf barn, its modes of operation are substantiated. It has been established that the power consumption for the fan drive during the operation of the air curtain is significantly less than the cost of thermal energy to compensate for the air temperature in the room from the inflow of cold air. The technical and economic calculation showed the effectiveness of the use of air heat curtains in microclimate systems for various livestock facilities of agricultural production.
The effectiveness of engineering systems at livestock enterprises is shown to be determined by the possibility of creating the required conditions where young animals are kept in interaction with external temperature parameters of their habitat. (Research purpose) The research aims to evaluate and choose a rational method for calculating radiant heat transfer in a system of surfaces with an arbitrary configuration that reflect the state of a biological object in a livestock room and the distribution of heat flows in the areas where young animals are located. (Materials and methods) The authors considered the conditions of a comfortable thermal regime for young animals and a physical model of animal heat transfer with the environment. The use of various methods for calculating heat transfer helped to determine the areas of change in the radiation panel temperature and the influence of the configuration and the system shell optical characteristics when creating comfortable conditions for keeping piglets. (Results and discussion) It was established that the computational model of heat transfer in a system of isothermal diffusely absorbing and radiating surfaces can be considered as an extension of existing computational methods. The model takes into account additional impact factors, including the influence of "hidden" surfaces through multiple reflections in a closed thermodynamic system. There is consistency between the results of heat transfer calculations by various methods, under the assumption that the system shell optical parameters are close to the characteristics of absolutely black body. (Conclusions) It was revealed that the system shell optical characteristics have a significant impact on the temperature regime of the irradiation panel surface, and the proposed computational model for determining the heated panel temperature regime in a system of isothermal diffusely absorbing and radiating surfaces can be applied to a wide range of agricultural premises of various configurations and geometries.
Mathematical formulation of the animal thermal status has been developed, with the account of two convenience conditions and heat balance, for the floor-mounted heating panel for prenursery pigs. The borders of the heat flux variation range for the floor-mounted heating panel have been determined corresponding to the animal-friendly conditions for prenursery pigs of various age groups. The block diagram of the energy-saving floor-mounted heating panel, comprising the thermoelectric assembly operating in the heat pump mode, has been designed. The method has been described and the corresponding calculations have been made for the basic thermal parameters of the floor-mounted local heating installation, for prenursery pigs, with the application of a thermoelectric heat pump. The experimental installation sample of 116 W thermal capacity (for the heat transfer coefficient from 0.9 W·m−2·K−1 to 1.0 W·m−2·K−1 and floor temperature in the range of 5 °C to 6 °C) has been developed and manufactured for local heating for prenursery pigs managed in gestation crates. Laboratory tests of the experimental sample of the floor-mounted heating panel have demonstrated high energy efficiency of the heating installation under development. The energy-saving effect (approx. 15% compared to the series-produced equipment designed for local heating of young stock) of the developed installation was achieved owing to the partial heat recuperation of the exhaust ventilating air.
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