Increasing the Comfort of the Work Environment of Ground Transport-Technological Machines by Optimizing the Thermal Energy Balance of the Microclimate

Abstract

The existing cabins of ground transport-technological machines have large glass surfaces to achieve enhanced visibility. In the warm seasons this leads to an increase in heat penetration due to the solar insolation. This leads to some issues as, on the one hand, operators need increased visibility in their cabins, but on the other hand, the thermal influence of solar insolation on the operator’s body must be reduced. Therefore, it is vital to optimize the thermal energy balance of the microclimate in the cabins of ground transport-technological machines through local thermoregulatory systems. To solve the existing problem, we set the goal of increasing the comfort of the work environment of ground transport-technological machines by optimizing the thermal energy balance of the microclimate. In order to achieve this goal, we set several tasks in the field of theoretical and experimental research to justify the design and operating parameters of a local thermoregulatory device for cabins of ground transport-technological machines. We theoretically determined the functional dependency connecting the design and operating parameters of the proposed device and identified design constraints. We described the procedure of our experimental research into the process of the formation of a comfortable thermal state for transport-technological machine operators both in standard conditions and under the influence of the developed thermoregulatory device. Experimentally confirmed the relationship between the important design parameters of this device (between the pitch and the diameter of the tubes) for different set values of the process of heat measuring, the temperature of the liquid, the thickness of the package of clothes and the surface temperature of the human operator. The dependences between the indicators of the thermal state of a human operator and the parameters of the proposed thermostatic device are obtained in the form of changes in the specific heat content of a person, which made it possible to optimize the design parameters. As a result of the research, optimal values of the heat flux density (268 W/m²) of the conductive panel of the device were determined taking into account the normative value of the temperature rise of the body temperature of a human operator (2°C per hour), which will ensure comfortable working conditions in the cabin of the mobile machine. The influence of body weight and human growth on the change in the parameter of the power density of the heat flow increases as the rate of increase in body temperature of the human operator increases. With the given limitations of the experiment, the optimal heat flow rate from the surface of the proposed device to the entire body surface of a human operator was revealed, which was 486 W with average values of body weight and height (70 kg and 1.7 m, respectively).