Heat pump working fluid selection—economic and thermodynamic comparison of criteria and boundary conditions

Zühlsdorf, Benjamin; Jensen, Jonas Kjær; Elmegaard, Brian

doi:10.1016/j.ijrefrig.2018.11.034

Cited by 55 publications

(19 citation statements)

References 34 publications

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“…In the context of optimizing the cycle performance by the working fluid choice, these variations may be understood as the potential improvements obtainable by the choice of an optimal working fluid. Morosuk and Tsatsaronis [17] indicated moderate improvement potentials for the analysed case, while it was shown in e.g., [5,6,18] that these improvement potentials may become considerable in applications with large temperature glides and for the utilization of zeotropic working fluid mixtures with a good temperature glide match. This paper therefore presents an analysis of the impact of the working fluid choice on the exergy destruction.…”

Section: Introductionmentioning

confidence: 90%

“…Recent studies on the optimization of heat pump systems by selecting the working fluid and the cycle layout have demonstrated a considerable potential for improvements in thermodynamic performance [5,6,18]. This optimization approach focused to some extent on the reduction of what was considered as unavoidable exergy destruction by advanced exergy analysis [17].…”

Section: Associating Exergy Destruction Due To Heat Transfer With Component or Cycle Layout And Working Fluidmentioning

confidence: 99%

“…Harby [4] reviewed the possibilities for using mixtures of hydrocarbons as replacement fluids and indicated an increased flexibility considering a limited number of pure fluids, which are suitable as long-term replacements. Zühlsdorf et al [5] analysed different approaches for comparing working fluids and suggested a procedure for identifying high-performance working fluids. It was demonstrated that zeotropic working fluid mixtures could yield a considerable increase in thermodynamic performance in applications in which the heat source and heat sink are experiencing a temperature glide.…”

Section: Introductionmentioning

confidence: 99%

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Exergy-based analysis of irreversibilities for heat pump working fluids and cycle layouts

Zühlsdorf

Jensen

Elmegaard

2021

IJEX

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The use of zeotropic mixtures in heat pumps in well-designed cycles enables considerable performance improvements beyond the limitations of conventional systems. A beneficial working fluid choice enables matching the temperature profiles of the working fluid and the secondary media. The reduced temperature differences in the heat exchangers decrease the exergy destruction and yield higher cycle performance. Further improvements may be obtained from installing internal heat exchangers and reducing the superheating inside the evaporator. Conducting an advanced exergy analysis for the evaluation of different cycle layouts and working fluids yields varying amounts of unavoidable exergy destruction depending on the scenario. These differences in unavoidable exergy destruction may be considered as the performance improvement potential obtainable by an optimization of the working fluid and the cycle layout. This study therefore suggests splitting the exergy destruction into two contributions, of which one is associated with the heat exchanger operating with an ideal fluid and the other with the fluid being non-ideal. Furthermore, the exergy destruction was related to deviations from the Lorenz cycle in terms of COP. The suggested concept was demonstrated by the case of a heat pump with different mixtures of propane/butane at different cycle layouts. The results were found to be a suitable measure of the potential performance improvement obtainable by working fluid and cycle layout optimization. Furthermore, relating the exergy destruction to changes in COP enabled an intuitive interpretation of the results.

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Section: Introductionmentioning

confidence: 90%

Section: Associating Exergy Destruction Due To Heat Transfer With Component or Cycle Layout And Working Fluidmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Exergy-based analysis of irreversibilities for heat pump working fluids and cycle layouts

Zühlsdorf

Jensen

Elmegaard

2021

IJEX

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“…However, the user should be able to check by himself/herself the potential of each refrigerant. Additionally, fluid mixtures with zeotropic behavior have shown a potential to increase the energy performance of HTHPs (Zühlsdorf;Jensen & Elmegaard, 2019). The possibility of blending refrigerants as well as advanced heat exchanger simulation could represent an exciting improvement for future versions of the software.…”

Section: Additional Working Fluidsmentioning

confidence: 99%

High-temperature heat pump simulator (heatpack) for application in computer laboratory sessions for engineering students

Mota-Babiloni

Mateu-Royo

Navarro-Esbrí

et al. 2021

J. Technol. Sci. Educ.

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A significant amount of energy in the form of heat is lost in industrial processes once it is used in specific processes. Among different technologies, high-temperature heat pumps (HTHP) are a valuable method of recovering low-temperature waste heat in the industry in a very efficient way that can be activated using clean electricity. As a recently investigated technology, they are not yet spread in industrial processes, where traditional technologies are preferred. Therefore, this work shows an HTHP computer program (named HeatPack) to be used as a simulator by the university or technical students of courses included in the area of applied thermodynamics engineering. This interactive and user-friendly platform allows the modification of different operating and design parameters and the working fluid. As outputs, the program provides the rest of the operating parameters and the energy performance of the cycle (quantified by the coefficient of performance, COP). A comparison between the proposed HTHP and a gas boiler is also performed by the program and the energetic, environmental, and economic savings are displayed. Students, as the main target of users of the program, can observe how this technology can provide very relevant emission reductions in comparison with fossil fuel-based boilers, under which situation the energy performance of the HTHP is higher, and which alternative low global warming potential (GWP) refrigerants can provide more advantages. In addition to the educational use, this software can be used to design and study the integration of HTHPs in existing industrial needs to evaluate the feasibility.

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“…Mancini et al (2018a) extended the work by comparing the degradation of heat transfer performance due to this kind of uneven liquid/vapour maldistribution for pure fluids and zeotropic mixtures. The use of a zeotropic mixture was demonstrated to increase the thermodynamic performance of heat pumps with respect to pure fluids by reducing the irreversibility in the HEXs (Zühlsdorf et al, 2019(Zühlsdorf et al, , 2018a. Zühlsdorf et al (2018a) further showed that the temperature glide match in the evaporator has a dominating effect compared to the condenser, which suggests that major attention should be given to the optimal design and operation of the evaporator.…”

Section: Introductionmentioning

confidence: 99%

Performance of heat pumps using pure and mixed refrigerants with maldistribution effects in plate heat exchanger evaporators

Mancini

Zühlsdorf

Aute

et al. 2019

International Journal of Refrigeration

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This paper presents a combined plate heat exchanger (PHE) -heat pump simulation framework for the evaluation of flow maldistribution in PHE evaporators and its effect on the cycle thermodynamic and economic performance. A case study of heat pump integration for waste heat recovery purposes in data centres was chosen to demonstrate the utilization of the simulation tool. The analyses were made for the pure fluids butane and propane, and for the zeotropic mixtures propylene/butane at (0.5,0.5) mass composition and CO 2 /dimethyl ether (DME) (0.2,0.8) as refrigerants. Both liquid/vapour maldistribution and the effect of end plates were considered in the heat exchanger models. Results show that butane is most sensitive to maldistribution, with a maximum Coefficient of Performance (COP) reduction of 5.9 %, while propane experiences the lowest reduction of 2.5 %. The different sensitivity of the working fluids to maldistribution was found to be related to the evaporator design, refrigerant pressure drop, and fluid properties. Last, the results of the economic analysis show that a higher specific cost of heat is obtained when considering maldistribution effects.

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Heat pump working fluid selection—economic and thermodynamic comparison of criteria and boundary conditions

Cited by 55 publications

References 34 publications

Exergy-based analysis of irreversibilities for heat pump working fluids and cycle layouts

Exergy-based analysis of irreversibilities for heat pump working fluids and cycle layouts

High-temperature heat pump simulator (heatpack) for application in computer laboratory sessions for engineering students

Performance of heat pumps using pure and mixed refrigerants with maldistribution effects in plate heat exchanger evaporators

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