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**Harvard**

Andreasen, J., Kærn, M., Pierobon, L., Larsen, U. och Haglind, F. (2015) *Multi-objective optimization of organic Rankine ycle power plants using pure and mixed working fluids*.

** BibTeX **

@conference{

Andreasen2015,

author={Andreasen, J. G. and Kærn, M. R. and Pierobon, L. and Larsen, Ulrik and Haglind, F.},

title={Multi-objective optimization of organic Rankine ycle power plants using pure and mixed working fluids},

booktitle={Proceedings of ASME ORC 2015},

pages={11},

abstract={For zeotropic mixtures, the temperature varies during phase change, which is opposed to the isothermal
phase change of pure fluids. The use of such mixtures as working fluids in organic Rankine cycle
power plants enables a minimization of the mean temperature difference of the heat exchangers when
the minimum pinch point temperature difference is kept fixed. A low mean temperature difference
means low heat transfer irreversibilities, which is beneficial for cycle performance, but it also results in
larger heat transfer surface areas. Moreover, the two-phase heat transfer coefficients for zeotropic mixtures
are usually degraded compared to an ideal mixture heat transfer coefficient linearly interpolated
between the pure fluid values. This entails a need for larger and more expensive heat exchangers. Previous
studies primarily focus on the thermodynamic benefits of zeotropic mixtures by employing first
and second law analyses. In order to assess the feasibility of using zeotropic mixtures, it is, however,
important to consider the additional costs of the heat exchangers. In this study, we aim at evaluating
the economic feasibility of zeotropic mixtures compared to pure fluids. We carry out a multi-objective
optimization of the net power output and the component costs for organic Rankine cycle power plants
using low-temperature heat at 90 ◦C to produce electrical power at around 500 kW. The primary outcomes
of the study are Pareto fronts, illustrating the power/cost relations for R32, R134a and R32/R134a
(0.65/0.35mole). The results indicate that R32/134a is the best of these fluids, with 3.4 % higher net power
than R32 at the same total cost of 1200 k$.
},

year={2015},

}

** RefWorks **

RT Conference Proceedings

SR Electronic

ID 224310

A1 Andreasen, J. G.

A1 Kærn, M. R.

A1 Pierobon, L.

A1 Larsen, Ulrik

A1 Haglind, F.

T1 Multi-objective optimization of organic Rankine ycle power plants using pure and mixed working fluids

YR 2015

T2 Proceedings of ASME ORC 2015

AB For zeotropic mixtures, the temperature varies during phase change, which is opposed to the isothermal
phase change of pure fluids. The use of such mixtures as working fluids in organic Rankine cycle
power plants enables a minimization of the mean temperature difference of the heat exchangers when
the minimum pinch point temperature difference is kept fixed. A low mean temperature difference
means low heat transfer irreversibilities, which is beneficial for cycle performance, but it also results in
larger heat transfer surface areas. Moreover, the two-phase heat transfer coefficients for zeotropic mixtures
are usually degraded compared to an ideal mixture heat transfer coefficient linearly interpolated
between the pure fluid values. This entails a need for larger and more expensive heat exchangers. Previous
studies primarily focus on the thermodynamic benefits of zeotropic mixtures by employing first
and second law analyses. In order to assess the feasibility of using zeotropic mixtures, it is, however,
important to consider the additional costs of the heat exchangers. In this study, we aim at evaluating
the economic feasibility of zeotropic mixtures compared to pure fluids. We carry out a multi-objective
optimization of the net power output and the component costs for organic Rankine cycle power plants
using low-temperature heat at 90 ◦C to produce electrical power at around 500 kW. The primary outcomes
of the study are Pareto fronts, illustrating the power/cost relations for R32, R134a and R32/R134a
(0.65/0.35mole). The results indicate that R32/134a is the best of these fluids, with 3.4 % higher net power
than R32 at the same total cost of 1200 k$.

LA eng

LK http://www.asme-orc2015.be/online/proceedings/documents/32.pdf

OL 30