Propan/Isobutan-Gemische als alternative Kältemittel in Kompressionskältemaschinen: Eine experimentelle Untersuchung

Venzik, Valerius; Roskosch, Dennis; Atakan, Burak

doi:10.1007/s10010-019-00389-8

Cited by 5 publications

(2 citation statements)

References 24 publications

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“…Only small benefits of mixtures compared with the better pure component were also reported by Park et al [ 14 ] for ethane/propane mixtures, and by Venzik et al for isobutane/propene mixtures [ 5 ] and isobutane/propane mixtures. [ 15 ] The main results of these studies can be summarized as follows: the COPs of both pure components differ, and the maximum COP is often observed for a specific composition. However, the COP of the best mixture composition is just a few percentage points higher compared with the better performing pure fluid.…”

Section: Introductionmentioning

confidence: 99%

Beyond Temperature Glide: The Compressor is Key to Realizing Benefits of Zeotropic Mixtures in Heat Pumps

et al. 2021

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Zeotropic mixtures are widely discussed as alternative refrigerants for vapor‐compression cooling appliances and heat pumps. Mixtures can increase efficiency due to their nonisothermal phase change. In theoretical studies, zeotropic mixtures show significant benefits for efficiency if the temperature glide of the mixture matches the temperature change in the heat transfer fluids. Such large benefits have never been observed in experiments. First, this article clarifies the gap between simulations and experiments. Second, it is shown how zeotropic mixtures could increase efficiency in real plants. The analysis is based on experimental results from a heat pump with three zeotropic mixtures and on theoretical studies that also include a physical compressor model. The compressor performance is shown to depend strongly on composition. Therefore, the compressor efficiency is the key parameter for large benefits of zeotropic mixtures beyond well‐matching temperature glides. Based on these findings, a fluid database is screened for fluids with well‐matching temperature glides and high compressor efficiencies, utilizing a physical compressor model. As a result of the screening, the zeotropic mixture R152a/R32 is identified. The corresponding simulations show that zeotropic mixtures can achieve large benefits in heat pump efficiency if the pure components have similar and high compressor efficiencies.

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Section: Introductionmentioning

confidence: 99%

Beyond Temperature Glide: The Compressor is Key to Realizing Benefits of Zeotropic Mixtures in Heat Pumps

et al. 2021

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“…The large family of molecules makes a suitable pool to draw from when designing refrigerant mixtures. A number of researchers have conducted experimental analyses of HC mixtures ( [11][12][13][14][15][16][17]). Most of the studies focused on refrigerant mixtures with glides of less than 20 K, as listed in Brendel et al [9].…”

Section: Introductionmentioning

confidence: 99%

Experimental Performance Comparison of High-Glide Hydrocarbon and Synthetic Refrigerant Mixtures in a High-Temperature Heat Pump

Brendel,

Bernal,

Arpagaus

et al. 2024

Energies

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Several theoretical studies have predicted that refrigerant mixtures with glides of more than 20 K can yield COP improvements in heat pumps for operating conditions where the temperature difference between the heat source and heat sink is large, but experimental validations and quantifications are scarce. The application of high-glide mixtures (>20 K) in industrial heat pumps in the field is, therefore, still hampered by concerns about the behavior and handling of the mixtures. This study experimentally investigates hydrocarbon (HC) mixtures R-290/600 (propane/butane) and R-290/601 (propane/pentane) and compares them to previously tested mixtures of synthetic refrigerants. Comprehensive evaluations are presented regarding COP, compressor performance, pressure drop, heat transfer, and the possibility of inline composition determination. The mixtures were tested over a range of compositions at a source inlet temperature of 60 °C and a sink outlet temperature of 100 °C, with the heat sink and heat source temperature differences controlled to 35 K. R-290/601 at a mass composition of 70%/30% was found as the best mixture with a COP improvement of 19% over R-600 as the best pure fluid. The overall isentropic compressor efficiency was similar for HC and synthetic refrigerants, given equal suction and discharge pressures. Pressure drops in heat exchangers and connecting lines were equal for synthetic and HC mixtures at equal mass flow rates. This allows higher heating capacities of HC mixtures at a given pressure drop (mass flow rate) due to their wider vapor dome. A previously developed evaporator heat transfer correlation for synthetic refrigerant mixtures was applicable to the HC mixtures. A condenser heat transfer correlation previously fitted for synthetic refrigerants performed significantly worse for HC mixtures. Composition determination during operation and without sampling was possible with a deviation of at most 0.05 mass fraction using simple temperature and pressure measurements and REFPROP for thermodynamic property calculations. Overall, high-glide HC mixtures, just like mixtures of synthetic refrigerants, showed significant COP improvements for specific operating conditions despite a decreased heat transfer coefficient. Potential problems like composition shift or poor compressor performance were not encountered. As a next step, testing high-glide mixtures in pilot-plant installations is recommended.

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Bewertung alternativer Arbeitsmittel für Wärmepumpen im Gebäudesektor

Höges

Venzik

Vering

et al. 2022

Forsch Ingenieurwes

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ZusammenfassungDas Arbeitsmittel in Wärmepumpen unterliegt einer Vielzahl von Anforderungen, welche für einen effizienten und sicheren Betrieb eingehalten werden müssen. Weiterhin steigt die Anzahl markterhältlicher Arbeitsmittel durch die Entwicklung neuer Gemische kontinuierlich an, wodurch deren Auswahl erschwert wird. Aus diesem Grund wird im Rahmen dieses Beitrags eine Marktanalyse alternativer Arbeitsmittel durchgeführt und die selektierten Arbeitsmittel hinsichtlich ihres Potentials für Wärmepumpen bewertet. Die Marktanalyse beinhaltet eine Einordnung der Arbeitsmittel durch politische Vorgaben (kein Ozonabbaupotential, geringes Treibhauspotential), sicherheitstechnischer Aspekte (Toxizität, Brennbarkeit) sowie technischer Anforderungen (unterkritischer Betrieb, maximale Prozesstemperaturen). Hierbei werden 32 Fluide identifiziert, welche die gestellten Anforderungen einhalten. Diese sind alle brennbar und größtenteils entweder Kohlenwasserstoffe (KW) oder Hydrofluorolefine (HFO). Anschließend wird die Effizienz im einfachen Kältekreislauf nach DIN EN 14825 bestimmt. Um die Fluidabhhängigkeit detailliert und realitätsnah abschätzen zu können, wird ein semi-physikalisches Verdichtermodell eingesetzt, welches fluid- und betriebspunktabhängige Verdichterwirkungsgrade liefert. Innerhalb der Kreislaufberechnung zeigen die Fluide RC270 und R161 die höchsten Effizienzen und führen zu einer Verbesserung der saisonalen Arbeitszahl im Vergleich zu R410A von bis zu 15 %. Diese führen aber zu hohen Temperaturen am Verdichteraustritt und sind daher ungeeignet. Weiterhin zeigen KW höhere Effizienzen als HFO. Bei der Wahl des Arbeitsmittels müssen allerdings weitere Aspekte, wie der Umwelteinfluss sowie Füllmengenbeschränkungen aufgrund der Brennbarkeit des Fluids betrachtet werden. Insgesamt weisen die Arbeitsmittel Propan und Propen das höchste Anwendungspotential auf. Für Anwendungen, in denen füllmengenbeschränkte Wärmepumpen erforderlich sind, bieten die HFO R454C, R457A und R516A effiziente Alternativen, deren Potenzial durch die Integration eines internen Wärmeübertragers in den Kältekreislauf gesteigert werden kann.

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Propan/Isobutan-Gemische als alternative Kältemittel in Kompressionskältemaschinen: Eine experimentelle Untersuchung

Cited by 5 publications

References 24 publications

Beyond Temperature Glide: The Compressor is Key to Realizing Benefits of Zeotropic Mixtures in Heat Pumps

Beyond Temperature Glide: The Compressor is Key to Realizing Benefits of Zeotropic Mixtures in Heat Pumps

Experimental Performance Comparison of High-Glide Hydrocarbon and Synthetic Refrigerant Mixtures in a High-Temperature Heat Pump

Bewertung alternativer Arbeitsmittel für Wärmepumpen im Gebäudesektor

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