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Papers by Dima Daniel
Technium: Romanian Journal of Applied Sciences and Technology
This study presents the energetic and energetic analysis of the heat pump cycle, used for heating... more This study presents the energetic and energetic analysis of the heat pump cycle, used for heating residential spaces. The heat pump is of the air-water type, taking heat at the level of the evaporator from the environment. The working fluids used are: R1233zd(E), R1234ze, R152a, R1234yf. Exergy analysis is used as a research tool. Based on the exergy analysis, the identification of malfunctions at the level of each device and process can be easily achieved. The study shows that the working fluid R1233zd(E) presents the highest coefficient of performance and the highest exergetic efficiency.
Cette invention concerne des systemes, des dispositifs, des circuits et des procedes pour un syst... more Cette invention concerne des systemes, des dispositifs, des circuits et des procedes pour un systeme ameliore de detection par spectrometrie de masse, comprenant une source d'ions et un detecteur fonctionnant a des polarites opposees. Selon certains modes de realisation, le systeme peut comprendre un multiplicateur positif et un multiplicateur negatif, dont chacun peut etre concu pour fournir de la tension a la source d'ions et au detecteur. Selon certains modes de realisation, le systeme peut comprendre des commutateurs qui permettent la commutation rapide entre les polarites positive et negative pour la source d'ions ou le detecteur. L'invention concerne en outre divers modes de realisation de systemes, dispositifs, circuits et procedes correspondants.
REVUE ROUMAINE DES SCIENCES TECHNIQUES — SÉRIE ÉLECTROTECHNIQUE ET ÉNERGÉTIQUE
The study is looking for the optimal configuration of an air-to-water heat pump capable of heatin... more The study is looking for the optimal configuration of an air-to-water heat pump capable of heating water in a flow-return system. Carbon dioxide is used as a working agent. In the optimization strategy, exergy analysis is considered. Using exergy analysis, the magnitude and the location of any functional or constructive malfunction can be revealed. First, a standard one-stage heat pump system is considered. Due to the high exergy destruction in the throttling valve, the efficiency of the standard system is improved by coupling it with an auxiliary one. The coupling process is undertaken in an internal subcooler-evaporator-heat exchanger. By subcooling the CO2 before entering the throttling valve of the standard cycle, the exergy destruction associated with this process diminishes. To increase the efficiency of the globally coupled system, the heat transferred outside in the gas cooler of the auxiliary heat pump is used in the water heating process. The energetic and exergetic effici...
Technium: Romanian Journal of Applied Sciences and Technology
This study presents the energetic and energetic analysis of the heat pump cycle, used for heating... more This study presents the energetic and energetic analysis of the heat pump cycle, used for heating residential spaces. The heat pump is of the air-water type, taking heat at the level of the evaporator from the environment. The working fluids used are: R1233zd(E), R1234ze, R152a, R1234yf. Exergy analysis is used as a research tool. Based on the exergy analysis, the identification of malfunctions at the level of each device and process can be easily achieved. The study shows that the working fluid R1233zd(E) presents the highest coefficient of performance and the highest exergetic efficiency.
Cette invention concerne des systemes, des dispositifs, des circuits et des procedes pour un syst... more Cette invention concerne des systemes, des dispositifs, des circuits et des procedes pour un systeme ameliore de detection par spectrometrie de masse, comprenant une source d'ions et un detecteur fonctionnant a des polarites opposees. Selon certains modes de realisation, le systeme peut comprendre un multiplicateur positif et un multiplicateur negatif, dont chacun peut etre concu pour fournir de la tension a la source d'ions et au detecteur. Selon certains modes de realisation, le systeme peut comprendre des commutateurs qui permettent la commutation rapide entre les polarites positive et negative pour la source d'ions ou le detecteur. L'invention concerne en outre divers modes de realisation de systemes, dispositifs, circuits et procedes correspondants.
REVUE ROUMAINE DES SCIENCES TECHNIQUES — SÉRIE ÉLECTROTECHNIQUE ET ÉNERGÉTIQUE
The study is looking for the optimal configuration of an air-to-water heat pump capable of heatin... more The study is looking for the optimal configuration of an air-to-water heat pump capable of heating water in a flow-return system. Carbon dioxide is used as a working agent. In the optimization strategy, exergy analysis is considered. Using exergy analysis, the magnitude and the location of any functional or constructive malfunction can be revealed. First, a standard one-stage heat pump system is considered. Due to the high exergy destruction in the throttling valve, the efficiency of the standard system is improved by coupling it with an auxiliary one. The coupling process is undertaken in an internal subcooler-evaporator-heat exchanger. By subcooling the CO2 before entering the throttling valve of the standard cycle, the exergy destruction associated with this process diminishes. To increase the efficiency of the globally coupled system, the heat transferred outside in the gas cooler of the auxiliary heat pump is used in the water heating process. The energetic and exergetic effici...