Bewertung alternativer Arbeitsmittel für Wärmepumpen im Gebäudesektor

Höges, Christoph; Venzik, Valerius; Vering, Christian; Müller, Dirk

doi:10.1007/s10010-022-00584-0

Cited by 4 publications

(2 citation statements)

References 28 publications

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“…The compressor model exhibits lean parametrization and does not rely on extensive compressor performance data. So far, the model has been used for pure refrigerants [ 30,31 ] and for refrigerant mixtures. [ 26 ] However, as a (semi‐)physical compressor model, it solves mass and energy balances and is therefore computationally expensive.…”

Section: Introductionmentioning

confidence: 99%

Refrigerant Selection for Heat Pumps: The Compressor Makes the Difference

et al. 2023

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Increasingly stringent regulations and new applications require selecting improved refrigerants for heat pumps. The selected refrigerants should be environmentally friendly and maximize the performance of the heat pump process. Systematic refrigerant selection methods usually model the compressor with one fixed isentropic efficiency identical for all refrigerants. However, compressor studies indicate that the isentropic efficiency may be highly refrigerant‐dependent. Herein, the need for a refrigerant‐dependent compressor model for refrigerant selection is investigated. For this purpose, a refrigerant‐dependent compressor model is combined with an integrated design of refrigerant and heat pump process. To guarantee a comparable nominal heating power among refrigerants, the compressor design is tailored to the refrigerant by expanding the refrigerant‐dependent compressor model toward compressor sizing. Integrating compressor design into systematic refrigerant selection is enabled by a computationally efficient model implementation. Accounting for refrigerant‐dependent compression substantially changes the resulting refrigerant ranking compared to the widely used assumption of identical isentropic efficiencies for all refrigerants: The best‐performing refrigerant is not even identified among the best ten refrigerants when assuming identical isentropic efficiencies. Consequently, compression is identified as the main driver for differences in refrigerant performance. Therefore, integrating refrigerant‐dependent compressor models is crucial for systematic refrigerant selection.

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Section: Introductionmentioning

confidence: 99%

Refrigerant Selection for Heat Pumps: The Compressor Makes the Difference

et al. 2023

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“…The refrigerants, however, are subject to increasingly strict political regulations that lead to maximum allowed limits for the GWP, refrigerant charges, and include bans on specified characteristics of refrigerants [4]. In search for possible alternatives that satisfy the political restrictions, the current research focuses on natural refrigerants and hydrofluoroolefins (HFO) since both have near zero GWP values [5][6][7][8]. However, selecting the optimal refrigerant is complex and depends on many boundary conditions.…”

Section: Introductionmentioning

confidence: 99%

How to Choose the Best Refrigerant in Heat Pumps from an Ecologic Perspective? Analyzing the Influence of the Evaluation Method

Höges,

Wissing,

Vering

et al. 2023

36th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems (ECOS 20

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Heat pumps are one of the key technologies to reduce CO2-emissions and reach a net zero building stock. However, heat pumps still induce CO2-emissions, which split up into direct and indirect emissions. Direct emissions result from leakages on site and indirect emissions mainly relate to the power consumption. In particular, the refrigerant choice influences both direct emissions due to its global warming potential, and indirect emissions due to the efficiency of the heat pump. Thus, the refrigerant choice is crucial to minimize the overall emissions of heat pumps. When selecting a proper refrigerant, several evaluation methods exist in the state of the art. In this work, we analyze the influence of the evaluation method on optimal fluid selection. Four methods are employed: Efficiency-based method using the seasonal coefficient of performance (SCOP), Total Equivalent Warming Impact (TEWI), Life Cycle Climate Performance (LCCP), and Life Cycle Assessment (LCA). The study includes ten refrigerants. For method comparison, the study includes refrigerants with either a high GWP or an ODP greater zero also to account for the sensitivity with respect to the evaluation method. The investigation shows only minor differences between the studied refrigerants when comparing the results of SCOP, TEWI and LCCP. The refrigerant ranking is not influenced by the assessment method. Main reason is the high share of the indirect emissions and thus, the dependency on SCOP. Using the LCA, the main difference occurs for refrigerants with an ODP. Using current regulations (zero ODP, GWP < 150), we conclude, SCOP comparison is a sufficient evaluation criterion when selecting refrigerants.

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