An Electromagnetic Time-Reversal Imaging Algorithm for Moisture Detection in Polymer Foam in an Industrial Microwave Drying System

Microwave tomography (MWT) based control is a novel idea in industrial heating systems for drying polymer foam. In this work, an X-band MWT module is designed and developed using a fixed antenna array configuration and integrated with the HEPHAISTOS industrial heating system. A decomposition of the time-reversal operator (DORT) algorithm with a proper Green’s function of multilayered media is utilized to localize the moisture location. The derived Green’s function can be applied to the media with low or high contrast layers. It is shown that the time-reversal imaging (TRI) with the proposed Green’s function can be applied to the multilayered media with a moderately rough surface. Moreover, a single frequency TRI is proposed to decrease the measurement time. Numerical results for different moisture scenarios are presented to demonstrate the efficacy of the proposed method. The developed method is then tested on the experimental data for different moisture scenarios from our developed MWT experimental prototype. Image reconstruction results show promising capabilities of the TRI algorithm in estimating the moisture location in the polymer foam.

A Review on Solar Thermal Utilization for Industrial Heating and Cooling Processes: Global and Ethiopian Perspective

A substantial share of the total energy in various countries is consumed by industries and manufacturing sectors. Most of the energy is used for low and medium temperature process heating (up to 3000C) as well as low and medium cooling capacity (up to 350kW). To meet the demand, the industrial sector consumes most of its energy in either thermal (heat) or electrical energy forms. The use of fossil fuels accounts for about half of the overall share. This resulted in a necessity to commercialize local and clean renewable energy sources efficiently considering the reduction of economic dependence on fossil fuels and greenhouse gases emission. As such, solar energy has proven potential and resulted in considerable development and deployment of solar heating industrial processes (SHIP) and solar cooling systems in recent times. Thus, an attempt to present a review of the available literature on overall energy intensiveness, process temperature levels, solar technology match, and solar thermal system performance and cost have been made in this paper. The review also includes identifying the potential and relevance of involving solar thermal for industrial heating and cooling demand. As a result, at least 624 SHIP including promising large-scale plants and 1350 solar cooling systems most of them in small and medium capacities in operation are identified. Though limited data is available for solar cooling potential and installation, investigations projected the global SHIP potential to 5.6 EJ for 2050. Consequently, given the presence of many low and medium temperature heating processes and cooling capacities in industries with immense solar energy potential, developing counties such as Ethiopia can take experience and pay attention to the development of sustainable industrial systems.

Optimization of the Initial Parameters of the Utilization Circuit of Cogeneration Combined Sycle Plant of Two Pressure Levels

This article is devoted to optimization of parameters and structure of the industrial-heating vapor-gas facilities (HVGF). The aim of the study is determination of the optimal initial parameters of two-circuit utilization HVGF. The set goal is achieved based on the methods of the mathematical modeling of the thermal schemes, using the elements of thermodynamic economic analysis. As the optimization criterion, the index of a relative fuel economy is used upon the combined generation of the energy and heat. The most significant result of the research consists in revealing a tendency to an increase in the optimal vapor pressure of the HVGF high pressure circuit, compared to a similar parameter of the condensation vapor gas device (VGD CEPP). For the two-circuit HVGF, the optimal initial pressure is 9.8—10 MPa (for the CEPP it is 8 MPa). The tendency is revealed for an increase of the relative fuel economy upon the complication of the HVGF thermal scheme. It was established that for the identic HVGF located in different energy systems, the relative fuel economy differ greatly. The relative fuel economy for the HVGF under consideration compared to analogous VGD CEPP is 27.35 %, and compared to the vapor turbine CEPP, the relative fuel economy will increase by 8.8 %. The importance of the results obtained consists in that their application will make it possible to increase the energy efficiency of the HVGF being constructed, and optimize the structure of the energy systems of separate regions and states.