The Experts below are selected from a list of 2118 Experts worldwide ranked by ideXlab platform
Andre Bardow - One of the best experts on this subject based on the ideXlab platform.
-
hybrid refrigeration by co2 vapour compression cycle and water based adsorption chiller an efficient combination of Natural working fluids
International Journal of Refrigeration-revue Internationale Du Froid, 2019Co-Authors: Andrej Gibelhaus, Nicolas Fidorra, Franz Lanzerath, Andre Bardow, Jurgen KohlerAbstract:Abstract Sustainable refrigeration systems are of great importance to reduce greenhouse gas emissions. In particular, CO2 vapour compression cycles are very promising due to their environmentally friendly, Natural Refrigerant. However, a major challenge for implementing CO2 cycles is the low efficiency at high ambient temperatures resulting from high exergy losses in transcritical operation. To increase the efficiency, we present a hybrid system concept integrating an adsorption chiller into the CO2 cycle. The adsorption chiller employs the Natural Refrigerant water and is driven by waste heat from the CO2 cycle. The additional cooling generated by the adsorption chiller is integrated into the CO2 cycle to increase the efficiency of the overall hybrid system. Compared to a stand-alone CO2 cycle, we show by dynamic modelling and optimisation that the hybrid system leads to annual energy savings of 22% for a warm climate in Athens and of 16% for a moderate climate in Cologne. The results highlight the high potential of the hybrid system concept to efficiently provide refrigeration using environmentally friendly Refrigerants.
V. P. Zhelezny - One of the best experts on this subject based on the ideXlab platform.
-
тhermodynamic properties of isobutane mineral compressor oil and isobutane mineral compressor oil fullerenes c60 solutions
International Journal of Refrigeration-revue Internationale Du Froid, 2019Co-Authors: V. P. Zhelezny, Olga Khliyeva, Mykola Lukianov, Igor Motovoy, Dmytro Ivchenko, Abdessamad Faik, Yaroslav Grosu, Artem Nikulin, António L. N. MoreiraAbstract:Abstract In present study a new experimental data for the saturated liquid density and saturated vapor pressure along the boiling line for the solutions of the ”Natural” Refrigerant isobutane (R600a) with mineral compressor oil and solutions of R600a/compressor oil/fullerenes C60 is presented. Moreover, a new experimental data on the specific isobaric heat capacity, enthalpy and entropy along the boiling line for the R600a/compressor oil solutions is reported. Experimental data of the two-phase isochoric heat capacity was obtained for different compressor oil fraction in the Refrigerant in the temperature range from 260 to 330 K. Obtained information was used to calculate the caloric properties of the R600a/compressor oil solutions. In addition, an influence of fullerene C60 on the specific isobaric heat capacity of mineral oil was examined. The measurements of the heat capacity for the R600a/compressor oil solutions, pure compressor oil and compressor oil containing fullerenes C60 were performed using an experimental setup that implements a direct heating method in adiabatic calorimeter. In addition, the heat capacity of oil and oil containing fullerenes C60 have been measured using differential scanning calorimetry. Finally, the heat capacity increase for the compressor oil with the additives of 0.0020 kg kg−1 of fullerenes C60 was observed.
-
Influence of compressor oil admixtures on theoretical efficiency of a compressor system
International Journal of Refrigeration-revue Internationale Du Froid, 2009Co-Authors: V. P. Zhelezny, Sergey V. Nichenko, B. V. Kosoy, Yury V. Semenyuk, Ravi KumarAbstract:Abstract This paper presents a theoretical evaluation of the influence of compressor oil admixtures on the thermodynamic performance of a vapor compression system using Natural Refrigerant R600a. The performance determination is based on the developed pressure–enthalpy diagrams (P–h) for the Refrigerant oil solution (isobutane-mineral compressor oil Azmol). A method for calculating the enthalpy of Refrigerant–oil solutions has been proposed and the influence of the compressor oil admixtures to isotherms the pressure–enthalpy diagrams has been analyzed. The change of enthalpy at the different oil concentrations in the working fluid in an evaporator has been investigated. An application of the developed Refrigerant–oil P–h diagrams for the theoretical evaluation of the efficiency of the vapor compression systems is also demonstrated.
António L. N. Moreira - One of the best experts on this subject based on the ideXlab platform.
-
тhermodynamic properties of isobutane mineral compressor oil and isobutane mineral compressor oil fullerenes c60 solutions
International Journal of Refrigeration-revue Internationale Du Froid, 2019Co-Authors: V. P. Zhelezny, Olga Khliyeva, Mykola Lukianov, Igor Motovoy, Dmytro Ivchenko, Abdessamad Faik, Yaroslav Grosu, Artem Nikulin, António L. N. MoreiraAbstract:Abstract In present study a new experimental data for the saturated liquid density and saturated vapor pressure along the boiling line for the solutions of the ”Natural” Refrigerant isobutane (R600a) with mineral compressor oil and solutions of R600a/compressor oil/fullerenes C60 is presented. Moreover, a new experimental data on the specific isobaric heat capacity, enthalpy and entropy along the boiling line for the R600a/compressor oil solutions is reported. Experimental data of the two-phase isochoric heat capacity was obtained for different compressor oil fraction in the Refrigerant in the temperature range from 260 to 330 K. Obtained information was used to calculate the caloric properties of the R600a/compressor oil solutions. In addition, an influence of fullerene C60 on the specific isobaric heat capacity of mineral oil was examined. The measurements of the heat capacity for the R600a/compressor oil solutions, pure compressor oil and compressor oil containing fullerenes C60 were performed using an experimental setup that implements a direct heating method in adiabatic calorimeter. In addition, the heat capacity of oil and oil containing fullerenes C60 have been measured using differential scanning calorimetry. Finally, the heat capacity increase for the compressor oil with the additives of 0.0020 kg kg−1 of fullerenes C60 was observed.
Banasiak Krzysztof - One of the best experts on this subject based on the ideXlab platform.
-
Experimental and numerical investigation of a transcritical CO2 air/water reversible heat pump: analysis of domestic hot water production
IIR, 2020Co-Authors: Tosato Giacomo, Artuso Paolo, Minetto Silvia, Rossetti Antonio, Allouche Yosr, Banasiak KrzysztofAbstract:As a Natural Refrigerant, carbon dioxide is safe, economic and environmentally sustainable and can be successfully utilized in heat pump and refrigeration systems operating according to transcritical cycles. This paper describes the development of a CO2 air/water reversible heat pump, specifically investigating the domestic hot water (DHW) production operating mode. A dynamic model of the heat pump is developed with the software Simcenter Amesim. After validation against experimental data, the numerical model is utilized to predict the performance of the heat pump to a varying hot water demand, evaporator air inlet conditions and high pressure value, leading to the discussion of the optimal control strategy. Keywords: Transcritical heat pump, Carbon Dioxide, Numerical model, COP, DHW, Energy Efficiency.acceptedVersio
-
Experimental and numerical investigation of a transcritical CO2 air/water reversible heat pump: analysis of domestic hot water production
'Siirt Universitesi Sosyal Bilimler Enstitusu Dergisi', 2020Co-Authors: Tosato Giacomo, Artuso Paolo, Minetto Silvia, Rossetti Antonio, Allouche Yosr, Banasiak KrzysztofAbstract:As a Natural Refrigerant, carbon dioxide is safe, economic and environmentally sustainable and can be successfully utilized in heat pump and refrigeration systems operating according to transcritical cycles. This paper describes the development of a CO2 air/water reversible heat pump, specifically investigating the domestic hot water (DHW) production operating mode. A dynamic model of the heat pump is developed with the software Simcenter Amesim. After validation against experimental data, the numerical model is utilized to predict the performance of the heat pump to a varying hot water demand, evaporator air inlet conditions and high pressure value, leading to the discussion of the optimal control strategy. Keywords: Transcritical heat pump, Carbon Dioxide, Numerical model, COP, DHW, Energy Efficiency
-
Experimental evaluation of CO2 ejector cooling system for supermarkets at tropical zones
'Purdue University (bepress)', 2018Co-Authors: Singh Simarpreet, Hafner Armin, Banasiak Krzysztof, P M MaiyaAbstract:Cooling system for supermarkets, now-a-days in developing countries like India, mainly use man-made synthetic Refrigerants/mixtures such as R134a, R404A and R410A (HFCs). These fluorinated Refrigerants possess outrageous impact on the environment/ambient due of their high GWP and ODP. The EU F-gas regulation is formulated recently and came into force in 2014 in order to restrict the use of synthetic Refrigerants for various HVAC applications. Under this regulation, it is also illegal to vent any such synthetic Refrigerants to the atmosphere during the system servicing or end-of-life decommissioning. Sudden phase down of HFCs forced the present scenario to identify a potential replacement of these synthetic Refrigerants. The influence of the same is comparatively high for developing countries. In the present study, the performance of a multi-ejector based supermarket cooling system is experimentally evaluated using Natural Refrigerant carbon dioxide (CO2). 33 kW cooling capacity of the system which is capable of maintaining three simultaneous different temperatures such as -29 °C for freezing, -6 °C for refrigeration and 7-11 °C for air-conditioning is examined at high ambient temperature context (up to 46 ºC gas cooler outlet temperature). The maximum COP of the supermarket cooling system appeared as 4.2. It is also observed that the maximum exergy efficiency of system is 0.316 obtained corresponding to 3.2 PIR of the system
Jahar Sarkar - One of the best experts on this subject based on the ideXlab platform.
-
thermodynamic analysis and optimization of a novel n2o co2 cascade system for refrigeration and heating
International Journal of Refrigeration-revue Internationale Du Froid, 2009Co-Authors: Souvik Bhattacharyya, Anirban Garai, Jahar SarkarAbstract:Abstract In this study, a Natural Refrigerant based cascaded system, with nitrous oxide as the low temperature fluid and carbon dioxide as the high temperature fluid, is analyzed for simultaneous cooling and heating applications. Effects of significant design and operating parameters on system performance are studied. Optimization of intermediate pressure for maximum COP for various design and operating parameters are presented as well. Results show that use of internal heat exchanger has marginal influence on system performance. Due to similar thermodynamic properties of nitrous oxide and carbon dioxide, the optimized intermediate temperature turns out to be independent of the performance of gas cooler and evaporator for a given operating condition. Due to the same reason, N 2 O as low temperature fluid and CO 2 as high temperature fluid in a cascade arrangement exhibit similar behavioural trends in a system where the fluids are swapped.
-
Natural Refrigerant-based subcritical and transcritical cycles for high temperature heating
International Journal of Refrigeration, 2007Co-Authors: Jahar Sarkar, Souvik Bhattacharyya, M. Ram GopalAbstract:Theoretical analyses of subcritical/transcritical heat pumps using four Natural Refrigerants, carbon dioxide, ammonia, propane and isobutane have been carried out for high temperature heating applications at different heating outlet temperatures and heat sources using computer models. The compressor discharge pressures have been optimized for transcritical and subcritical (with near critical operation of condenser) cycles. Results show that for subcritical heat pumps, use of subcooling is efficient for heating applications with a gliding temperature. Results also show that although propane yields better coefficient of performance (COP) in low temperature heating applications, ammonia performs the best in high temperature heating applications. Finally, design aspects of major components of all the four heat pumps for high temperature heating have been discussed, particularly with reference to suitability of available lubricants to the newly evolved operating conditions.
