Papers by Keyword: Heat Recovery

Abstract: In this study, we compared the closed mines of the Donetsk basin of Ukraine and the Ruhr coal mining area of Germany by the conditions of mine water heat recovery. The set of criteria includes maximum thermal capacity, heat pump COP, the relation of energy gained to energy spent, potential profit of operation, and CO₂ emission reduction. The complex indicator of efficiency that comprises all these parameters was used to rank eight mine drainage stations in Ukraine and the same number in Germany. Based on the calculations for potential open-loop and closed-loop systems, we revealed statistically significant correlations between expected energy efficiency, the water temperature, and the flooding interval length for 27 mines in Ukraine and 28 mines in Germany. The average expected thermal capacity of closed-loop systems at the current water level in the mines of the two basins is similar, against the background of higher heterogeneity of geothermal conditions in Donbas and greater depths and higher temperatures in Ruhr area mines. The similarity of mining conditions and estimated energy efficiency indicators of geothermal systems for two basins is in favor of the feasibility and efficiency of such systems in Ukrainian mining sites.

Abstract: Increasing demands for reducing greenhouse gases drive the metal processing industries to a CO₂-neutral production. A thorough understanding of CO₂ emission sources from the stage of material acquisition up to the final component is thus necessary to improve the CO₂ footprint of sheet metal hot forming process chains. To emphasize on this, an exemplary hot forming process chain is assessed to identify the impact of each sub-process step on total CO₂ emissions and the savings potential of individual measures is evaluated. Moreover, a mathematical model is proposed that enables for the prediction of the product specific CO₂ emissions as early as in the product design stage. This model is tested to calculate the CO₂ emissions resulted during the production of an exemplary hot stamped sheet component. The results point out that the heating stage is responsible for the second highest percentage of CO₂ emissions in the process chain next to the material acquisition. Thus, as one of the most suitable measures, a concept to recover process heat from hot formed components to the cold initial blanks is proposed and evaluated analytically.

Abstract: A promising approach for increasing the energy efficiency of domestic households and buildings is to optimize the whole energy system by coupling of different heat sources and sinks. This procedure, known as heat integration, is state of the art in the industrial sector and is now applied to the residential sector. In this work several options for increasing the energy efficiency and for recovering waste heat are discussed. In order to reduce the primary energy demand different waste heat sources like domestic hot water or household appliances (refrigerators or freezers) were evaluated. The first step is the development of an advanced form of the stationary Pinch Analysis. This was subsequently applied to determine the thermodynamically possible energy saving for a single family home.

Abstract: This research presents a passive method of waste heat recovery and conversion to electricity using Thermo-Electric Generator (TEG). For this purpose, a lab scale bench-top prototype of waste heat recovery and conversion system was designed and fabricated. This bench top system consists of the thermoelectric generators (TEGs) sandwiched between two heat pipes, one connected to the hot side of the TEG and the second connected to the cold side of the TEG. A 2 kW electric heater was used to replicate the waste heat. An electric fan was used to provide air into the system. A theoretical model was developed to predict the system performance. The model was found in good agreement with the experimental data.

Abstract: The air preheater was installed on the furnace to decrease the exhaust gas temperature and heat the air to about 290°C. A radiant cylinder was added to the radiation section. Swirl flames were formed by adjusting the shape and the installation angles of the burner flame tubes. The radiation heat transfer was strengthened and the heat absorption was enhanced in the radiation section, while the temperature at the outlet of the furnace was decreased. Thus energy was saved by 16.7%.

Abstract: Nowadays it is possible to reduce energy consumption without losing comfort as a result of using efficient energy saving technologies and advanced environment control methods for buildings. One of the measures to improve energy performance of buildings can be installation of decentralized air intake and exhaust mechanical ventilation systems with plate heat exchangers in apartments making it possible to «return» up to 85% of thermal energy. The article deals with the decentralized system controlled ventilation with heat recovery and alternative solutions heating supply air in residential buildings.

Abstract: Decentralized ventilation systems applied in residential buildings are generalized in this article. Basic system elements and devices and tools assigned for its application are considered herein. Basic requirements for design of the ventilation systems used in residential buildings are stipulated.

Abstract: The paper presents the work developed in the first stage of Research Grant called "Hybrid micro-cogeneration group of high efficiency equipped with an electronically assisted ORC" (acronym GRUCOHYB). The Research Grant is in progress at the Thermal Research Centre, Faculty of Mechanical and Mechatronics Engineering from University Politehnica of Bucharest having as research partner the Rokura Company. The hybrid micro-cogeneration group involves the use of an electric generator based on a 40 kW overcharged Diesel engine and an Organic Rankine Cycle (ORC). The aim of the research is to recover the waste heat available in the exhaust gas and cooling water and transfer it to the ORC in order to convert it into electricity. A description of the experimental setup is given according to the current stage of development. Also the paper presents the experimental results obtained and which show the amount of waste heat available for recovery for different engine operation loads. Based on these experimental results the proper ORC configuration and working fluid can be determined. Several possible ORC configurations suitable for this application are highlighted. Future work and development perspectives are also discussed.

Abstract: Historic apartment buildings in Saint-Petersburg no longer meet today’s energy efficiency standards and need upgrading to achieve lower energy-consumption. The possibilities to upgrade old buildings – historic and cultural monuments – are initially limited. A controlled heat recovery ventilation system is considered to be an integral part of energy efficient building. Provided engineering facilities of a building are updated and reequipped energy performance increases without any impact on building exteriors. Different types of decentralized intake and exhaust ventilation systems with heat recovery based on various types of heat exchangers are considered in a detailed way.

Abstract: Economic performance of investment capital, operational costs and supplying costs of domestic hot water for different scenarios of ground source heat pump system (GSHPS), which designed for a hotel located in the hot summer and warm winter area, have been analyzed using the dynamic annual cost method. The results show that the investment capital decreased while the operational costs increased first and then decreased with the ratio of waste heat recovery of GSHPS increased. The comprehensive benefit of GSHPS with waste heat recovery is distinct compared with conventional GSHPS. When the ratio of waste heat recovery is 50%, the dynamic annual costs of GSHPS are minimum and achieve the optimization of energy-saving effect.