In this article, the object of study is a research drying chamber of a convective type, in the design of which a condensing heat exchanger based on a vapor-compression heat pump is introduced. The drying process of lumber refers to energy-intensive technologies, since the share of drying in the cost of finished materials reaches 50% [1]. In the presented experimental study, comparative results of two operating modes of the experimental installation are presented: standard (soft mode) and recirculation mode with a condensate dryer. The obtained experimental drying curves show that the cost of electrical energy, taking into account the option with a condensing heat exchanger, decreased by 7.75% compared to the standard.

Keywords: drying modes, drying, heat pump unit, heat recovery unit, material balance, heat balance, moisture content, heat consumption, experimental setup

The article considers the improvement of the centralized heat supply system (SCT) from Saransk CHP-2 by optimizing the calculated quantitative and qualitative parameters of the hydraulic regime due to circuit solutions (optimization of the thermal circuits of the CTP and etc.), including the distribution of thermal loads; the use of devices (installations) providing the expansion of the temperature schedule of heat supply to the network. This event will allow: to create the technical possibility of technological connection of a promising thermal load; to reduce specific fuel consumption by increasing the share of combined power generation at Saransk TPP-2; will ensure an increase in the utilization rate of the installed thermal capacity of Saransk TPP-2 to 45-50%.

Keywords: temperature chart; hydraulic mode; combined production; central heating point

Within the Tresca yield criterion and its associated flow rule, the stress-strain problem in an elastic-plastic thin circular solid disk is considered under a temperature field such as the yield stress of the material depends on the temperature. In the central part of the disk the temperature is homogeneous. On the outer boundary, the disk is subjected to uniformly distributed pressure and constant temperature. The objective of the paper is to determine the service conditions which allow to obtain the temperature in the central part of the disk and its radius such as the initiation of the plastic zone starts either from the center of the disk or from its outer contour. The elastic-plastic boundary is calculated, and the plots for stresses and strains are presented. To verify the solution, the equivalent stresses for permissible plastic regimes are investigated together with the stress vector hodograph . The algorithm of similar problems is developed. The validity of the usage of the Tresca yield criterion when the yield stress of the material depends on the temperature is discussed.

Keywords: mathematical modeling, elastoplastic body, plane stress state, piecewise linear plasticity conditions, plastic flow theory, thermoelastic plasticity