[en] The reader will achieve a benchmark understanding of the essence of cleaning for the removal of contaminants from machine elements by means of cryo jet/ water-ice jet with particles prepared beforehand. This paper represents the classification of the most common contaminants appearing on the surfaces of machine elements after a long-term service. The conceptual contribution of the paper is to represent a thermo-physical model of contaminant removal by means of a water ice jet. In conclusion, it is evident that this study has shown the dependencies between the friction force of an ice particle with an obstacle (contamination), a dimensional change of an ice particle in the cleaning process and the quantity of heat transmitted to an ice particle. (paper)

[en] Earlier studies have confirmed the reasonability of using thermoelectric converter (TEC) for heat recovery of electrolytic gases. The use of process flow diagram, which consists of a heat exchange unit along with thermoelectric converters is an innovative technology and will allow to increase the energy efficiency of production and achieve economic advantages of the aluminium production process. (paper)

[en] The increase of energy efficiency and energy saving are the main indicators of the improvement and growth of the competitiveness of the Russian economy. One of the system approaches is saving of energy resources through heat recovery. The use of heat recovery units and assessment of the boundaries of their effective use are rather relevant for regions with a long heating period and low negative temperatures. The study proves that special climatic conditions of the Southern Urals provide certain benefits when using heat recovery units in the cold season, relative to other regions, which allows us to use them effectively in ventilation and air conditioning systems throughout the year. (paper)

[en] This study addresses the funding of heat recovery projects, and aims at identifying brakes to be lifted in order to improve project valorisation, at identifying all risks to be covered during the financial arrangement, and at proposing the most relevant tools to do so. It focused on heat recovery in industrial sites and in waste elimination sites for a purpose of internal or external heat valorisation. It proposes an overview of projects of valorisation of industrial recovery heat (definition, key activities and actors, identification of four main project types, definition of project structure phases and of associated activities), proposes a methodology of project analysis applied to heat recovery (components related to investment decision, funding modes), identifies risks (risk definition, risk assessment, identification of main risks), proposes an overview of the main deadlock points noticed in existing projects, briefly describes solutions which are implemented in the world or in other activity sectors. Then, it reports a synthetic analysis of existing and mobilizable funding tools, and reports an application of this analysis to three different cases. Recommendations are then stated for a higher transparency and a better analysis method, for the implementation of specific arrangements, with a focus on exceptional depreciations and on various subsidies. An appendix contains an inventory of arrangements. A synthetic version of this report is provided

[en] Grate coolers which represent one of the pyro-processing units are extensively used in cement industries. The essential function of grate coolers is a waste heat recovery from hot clinker which leaves the rotary kiln. This paper presents an analysis of energy and exergy based on the clinker temperature profile. It focuses on the distributions of temperature, energy and exergy for cooling air and hot clinker along the grate cooler in cement industries. Consequently, this distribution allows predicting the temperatures of secondary air, tertiary air, and exhaust air, which will lead to estimation of waste heat recovery from the clinker cooler system. (paper)

[en] In this paper, results of numerical analysis of the energy-technological complex consisting of the gas piston power plant, the torrefaction reactor with recirculation of gaseous heat carrier and the heat recovery boiler are presented. Calculations of the reactor without recirculation and with recirculation of the heat carrier in torrefaction zone at different frequencies of unloading of torrefied biomass were held. It was shown that in recirculation mode the power of the gas piston power plant, required for providing given reactor productivity, is reduced several times and the consumption of fuel gas, needed for combustion of volatile torrefaction products in the heat recovery boiler, is reduced by an order. (paper)

[en] After a brief presentation of the context related to the potential of recovery of unavoidable heat in data centres, this report proposes a description of the operation principle of a data centre (specific stakes, the data centre market, the Uptime Institute classification, description of the operation, main equipment and technologies, performance indicators, energy performance and optimizations), a description of the progress status of technologies of reduction of electric power consumption (air management, optimization of fluid regimes, cooling optimization, replacement of power supply by a local production, heat recovery, assessment of technologies of energy optimization and of heat recovery), a comment of returns on experience, a description of the sector situation, a study of potential deposits and a definition of prioritization, and propositions of levers of actions for the mobilization of identified deposits

[en] In many important industries (oil and gas, process gases, chemical process engineering) multi-stage reciprocating compressors are used, especially for high pressure ratios. The gas is compressed in multiple consecutive stages and cooled after each stage in order to reduce the maximum process temperatures. The rejected heat is often dissipated to the environment and the usable part – the exergy – is lost.

The aim of this paper is to show how the waste heat potential of reciprocating compressors can be used. For this purpose, the waste heat available per stage is quantified for different compression scenarios. Based on this, the processes for the waste heat recovery suitable for the temperature range of the discharge gas as heat source are presented – in particular the structure, working principle and characteristics of the waste heat recovery system. It is shown that the waste heat can be used flexibly for different purposes (heating, power generation, cold supply). The potential of the possible methods of waste heat recovery can be estimated with the aid of the given efficiencies of the respective energy conversion processes. (paper)

[en] Solar cell thermal recovery has recently attracted more and more attention as a viable solution to increase photovoltaic efficiency. However, the convenience of the implementation of such a strategy is bound to the precise evaluation of the recoverable thermal power and to a proper definition of the losses occurring within the solar device. In this work, we establish a framework in which all solar cell losses are defined and described. The aim is to determine the components of the thermal fraction. We therefore describe an experimental method to precisely compute these components from the measurement of the external quantum efficiency, the current–voltage characteristics, and the reflectivity of the solar cell. Applying this method to three different types of devices (bulk, thin film, and multi-junction), we could exploit the relationships among losses for the main three generations of PV cells available nowadays. In addition, since the model is explicitly wavelength dependent, we could show how thermal losses in all cells occur over the whole solar spectrum, and not only in the infrared region. This demonstrates that profitable thermal harvesting technologies should enable heat recovery over the whole solar spectral range.

[en] Ultra-low energy buildings focus on realizing ultra-low energy consumption mainly by virtue of passive mode and providing a comfortable indoor environment. Such buildings mainly rely on high-performance envelope, fresh air heat recovery, air tightness, adjustable shade and other building technologies to enable ultra-low energy consumption. However, the difficulty mainly lies in technical suitability. That is, how to meet the energy requirements of heating and cooling under the conditions of non-mechanical, no energy or less energy consumption through reasonable design of key technologies. Combining with the climate characteristics of Beijing, this paper studies the key technologies of ultra-low energy buildings and attempts to make active exploration on the technical advance of ultra-low energy buildings. (paper)