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Abstract

The purpose of the work was initial modification of the construction of a commercially produced heat exchanger – recuperator with CFD (computational fluid dynamics) methods, based on designs and process parameters which were provided. Uniformity of gas distribution in the space between the tubes of the apparatus as well as the pressure drop in it were taken as modification criteria. Uniformity of the gas velocity field between the tubes of the heat exchanger should cause equalization of the local individual heat transfer coefficient values and temperature value. Changes of the apparatus construction which do not worsen work conditions of the equipment, but cause savings of constructional materials (elimination or shortening some parts of the apparatus) were taken into consideration.

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Authors and Affiliations

Wojciech Ludwig
Daniel Zając
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Abstract

The research provides a thermodynamic analysis of the theoretical model of a ventilation and air conditioning heat pump system with the ventilation air cold energy recovery depending on outside air parameters, the recovery efficiency and characteristics of a premise. A confectionery production workshop was taken as a prototype where technological conditions (temperature and humidity) must be maintained during the warm season. Calculations using the method of successive approximations to estimate air parameters at system’s nodal points were conducted. It allowed to determine theoretical refrigeration efficiency of the studied system and proved advantages of heat recuperation for smaller energy consumption. The model can be applied for design of heating, ventilation, and air conditioning units which work as a heat pump. The studied system has the highest energy efficiency in the area of relatively low environment temperatures and relative humidity which is suitable for countries with temperate continental climates characterized by low relative humidity.
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Bibliography

[1] Zhang J., Zhang H.-H., He Y.-L., Tao W.-Q.: A comprehensive review on advances and applications of industrial heat pumps based on the practices in China. Appl. Energ. 178(2016), 800–825.
[2] Chwieduk D.: Analysis of utilization of renewable energies as heat sources for heat pumps in building sector. Renew. Energ. 9(1996), 720–723.
[3] Khrustaliov B.M.: Heat Supply and Ventilation. ASV, Moscow 2007 (in Russian).
[4] Mazzeo D.: Solar and wind assisted heat pump to meet the building air conditioning and electric energy demand in the presence of an electric vehicle charging station and battery storage. J. Clean. Prod. 213(2019), 1228–1250.
[5] Chwieduk B., Chwieduk D.: Analysis of operation and energy performance of a heat pump driven by a PV system for space heating of a single family house in Polish conditions. Renew. Energ. 165(2021), 117–126.
[6] Bezrodny M., Prytula N., Tsvietkova M.: Efficiency of heat pump systems of air conditioningfor removing excessive moisture. Arch. Thermodyn. 40(2019), 2, 151–165.
[7] Bezrodny E.K., Misiura T.O.: The heat pump system for ventilation and air conditioning inside the production area with an excessive internal moisture generation. Eurasian Phys. Tech. J. 17(2020), 118–132.
[8] Adamkiewicz A., Nikonczuk P.: Waste heat recovery from the air preparation room in a paint shop. Arch. Thermodyn. 40(2019), 3, 229–241.
[9] Szreder M.: Investigations into the influence of functional parameters of a heat pump on its thermal efficiency. Teka. Commission of Motorization and Energetics in Agriculture 13(2013), 191–196.
[10] Redko A., Redko O., DiPippo R.: Low-Temperature Energy Systems with Applications of Renewable Energy. Academic Press, Elsevier, 2020.
[11] Morozjuk T.V.: The Theory of Chillers and Heat Pumps. Studija “Negociant”, Odessa 2006 (in Russian).
[12] Jaber S., Ezzat A.W.: Investigation of energy recovery with exhaust air evaporative cooling in ventilation system. Energ. Buildings 139(2017), 439–448.
[13] Bozhenko M.F.: Heat Sources and Heat Consumers. NTUU KPI “Politehnika”, Kyiv 2004 (in Ukrainian).
[14] State Building Standards of Ukraine DBN B.2.5-67: 2013, “Heating, ventilation and air conditioning”. Ministry of Regional Development, Construction and Housing of Ukraine, Kyiv 2013 (in Ukrainian).
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Authors and Affiliations

Myhailo Kostiantynovych Bezrodny
1
Tymofii Oleksiyovych Misiura
1

  1. National Technical University of Ukraine, Igor Sikorsky, Kyiv Polytechnic Institute, Prosp. Peremohy 37, 03056 Kyiv, Ukraine
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Abstract

In order to select the most optimum parameters for running heat recuperation process from aerobic composting process, three testing stages were run involving the registration of the value of recuperated heat volume and the observation of cooling impact on composting process parameters. The values of thermal conductivity coefficient were measured as a function of compost temperature, density and age. The values ranged from 0.171 to 0.300 W/mK. The optimum parameters for process running were selected. Basing on them it was estimated how much heat will be possible to recuperate during the composting process on industrial scale using a battery of heat exchangers. For artificially aerated pile with the following dimensions: lower base 8 m, upper base 5 m, height 3.5 m, length 3 m; it will be possible to recuperate approximately 7.4 kW (from 1 m2 of heat exchanger surface - 774 W).
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Authors and Affiliations

Ewa Klejment
Marian Rosiński
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Abstract

In this article I will try to describe the lesson learnt by the corporations from the grass root movements in the cities. In the proposed analysis I will refer to the conception of recuperation and a soul of capitalism – by Luc Boltanski and Ève Chiapello. Besides it I will refer to the works of these authors who analyse the beginnings and the activism of the city grass-root movements in a context of critique of capitalism and neoliberal system.

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Authors and Affiliations

Jan Śpiewak
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Abstract

The objective of the project was to find out whether the composting process of municipal waste may be used as a low temperature heat source. It was determined that during high temperature phase of the process on average 930.5 kJ of heat is produced per kg of compost. The designed and made laboratory model was used for carrying out three stages of testing, boiling down to running the composting process with parallel heat recuperation from the process. Basing on the tests, the parameters having affecting the heat recuperation process effectiveness were determined, viz.: optimum initial temperature of cooling water should be approximately 30°C, the reduction of flow rate of the cooling water has advantageous impact on the increase of process efficiency, whereas the safe temperature lower limit for compost cooling should be higher than 52°C (which safeguards compost sanitary purity). It was also observed that in parallel to compost age heat recuperation process efficiency is declining.
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Authors and Affiliations

Ewa Klejment
Marian Rosiński
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Abstract

The Authors present the problems of theoretical analysis and experimental research related to the possibilities of energy recovery in selected phases of operating and running cycles of self-driven crane. Heavy machinery powered by diesel engines is a source of solid toxic emissions. In order to limit these emissions, one install filters and filter regeneration systems. According to the concept presented here, the recovered energy might be utilised for regeneration of these filters by burning off accumulated solid particles (soot). Mechanical energy would be the power source to drive DC generators - the mechanical-into-electric energy converters. Filter's heating resistors, acting as the generators' load, would radiate a power of 3-;-5 MJ to initiate burning of soot in the filter. The calculations of energy consumed during sheave block lowering phase were made for three different lifting capacities taking into account the boom length and crane reach. Three running cycles of the crane: highroad, urban and off-road ones were also analysed. The time functions of variations of crane running speed and power of motion resistance at driving wheels were found. The results provided the background for determination of theoretical values of energy to be regained during braking phase of the analysed cycles. The structure and operation of experimental stands was discussed. The stands contain units that, at proper size factor, represent the processes that occur in real cranes and that are related only to energy recovery. Computer software for system simulation, control and measurement was described. Measurement results and result analysis are presented. The value of energy found theoretically was compared with the energy recovered during experimental tests. The paper also contains simplified kinematic schemes of selected units of crane lifting and driving systems, including an additional DC generator. This concept, however, needs verification in future design solutions.
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Authors and Affiliations

Jerzy Ocioszyński
Przemysław Majewski

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