Forecasting the thermal performance of the natural ventilation system used in a cowshed

Abstract

To predict the thermal characteristics of an air solar collector mounted on the outer walls of the cowshed, the authors proposed a mathematical model based on the linear dependence of the change in the temperature of the heat-receiving surface during the day, taking into account variable environmental factors. The present study proposes to apply a quadratic dependence of the ambient temperature on the time of day. The ambient temperature and the flux density of solar energy reaching the vertical surface, depending on the time of day, differs for different regions of the country, seasons, as well as within the same season. The study aims to establish these dependences for the conditions of the Bryansk region based on the materials of actinometric observations of meteorological stations with a period of at least 5 years. The study measured direct solar radiation reaching the cowshed surface perpendicular to the sunlight. Equations were obtained for both clear sky and medium cloudiness conditions for the middle day of each month of the year assuming that the dependences would be characteristic of all days of a given month. As a result of the research, regression dependences describing the diurnal course of air temperature and solar radiation intensity for the median months of the seasons (January, April, July, and October) were obtained. The obtained results may help increase the accuracy of calculations of the temperature of the heat-receiving surface of ventilation and heating panels taking into account environmental factors and to provide forecasting of the thermal characteristics of the natural ventilation system of the cowshed.