It has been shown that the efficiency of engineering systems for creating a microclimate at livestock facilities is determined by the possibility of organizing the required thermal conditions in interaction with external temperature parameters of enclosing structures. (Research purpose) The research purpose is developing a method for calculating and modeling the thermal mode in the piglets’ location zone using an infrared irradiation panel in a system of diffusely absorbing and radiating surfaces. (Materials and methods) Considered the conditions of a comfortable thermal regime for young animals, the physical model of a piglet, the conditions of heat exchange. The areas of temperature change of the irradiating panel and the influence of the configuration of the optical characteristics of the system shell when creating comfortable conditions for keeping piglets, depending on the age and temperature parameters of the enclosing structures, were presented. (Results and discussion) It was found that the computational model of heat transfer of an animal on the example of a piglet in a system of isothermal diffusely absorbing and radiating surfaces serves as an extension of existing computational methods. (Conclusions) It has been shown that the mathematical model of heat exchange of an animal in a system of diffusely absorbing and radiating surfaces more fully reflects the interrelationships in the elements of the biotechnical system, this allows more accurately forming and maintaining the specified temperature conditions for the comfortable maintenance of young animals. We have obtained a functional model reflecting the dependences of the thermal state of piglets, taking into account their age, on the ambient temperature, the design parameters of the radiating panel and its temperature on the surface. The main correlations linking the conditions of thermal comfort of piglets with the temperature of the radiating surface of the panel, with the temperature and optical properties of the enclosing structures of the room were revealed. The scheme of the algorithm for calculating the surface temperature of the radiant panel was given. The range of panel surface temperature values was determined depending on the temperature of the enclosing structures for the conditions of a comfortable thermal condition of animals in the heating zone, taking into account their age.