Hochschule Bremen - University of Applied Sciences

Hochschule Bremen

Dimensioning procedure and program for working fluid selection and optimization of ORC process

Begutachtete Publikation

Natur und Technik

Julius Robert Mayer - Institut für Energietechnik

Smolen, Slawomir, Prof. Dr.-Ing.
Boertz, Hendrik
Hansen, Denny
Roman, Simona


Autor_innen, Jahr, Titel
Slawomir Smolen
3rd International Conference:
“Low Temperature and Waste Heat Use in Communal and Industrial Energy Supply Systems, Theory and Practice”
Proceedings, October, 25th-26th, 2012, page: 164

Weitere Informationen
Proceedings, University of Applied Sciences Bremen

Proceedings LTWHU 2012
Proceedings Low Temperature and Waste Heat Use 2012
Dimensioning procedure and program for working fluid selection and optimization of ORC process
Slawomir Smolen, Hendrik Boertz, Denny Hansen
University of Applied Sciences Bremen
Faculty Nature & Engineering
Department of Mechanical Engineering
Neustadtswall 30
28199 Bremen, Germany

Simona Roman
Technical University of Cluj-Napoca
Cluj-Napoca, Romania

1 Abstract

The presented dimensioning procedure and program for working fluid selection and optimization of ORC process is the further development of the former practical orientated research work [1]. The selection of suitable organic fluids for use in Organic Rankine Cycle for waste energy recovery from many potential sources of low-medium temperature is a crucial step to achieve high thermal efficiency. In order to identify the most suitable organic fluids, several general criteria have to be taken into consideration. The aim of the former study [1] was to elaborate a tool for the comparison of the influence of different working fluids on performance of an ORC heat recovery power plant installation. A database of a number of organic fluids which allows the user to select the proper organic fluid for particular application has been developed. Calculations have been conducted for the same heat source and installation component parameters. The elaborated tool should create a support by choosing an optimal working fluid for special applications and become a part of a bigger optimization procedure by different frame conditions.

The current development and extension of the procedure consider the practical requirements and constitute the next stage in order to adapt the elaborated program as an ancillary tool for concrete applications and dimensioning of the technical installations.

The most important progress involves the consideration of heat transfer calculations, i.d. the heat transfer between the heat source and the ORC-Process, the internal heat recovery and condenser. The temperature profiles within the heat exchangers are calculated, the general parameter of heat exchanger (k*A) can be assumed and thereby the components of the installation can be dimensioned. Of course the calculations have to be repeated for the chosen or new designed heat exchangers in order to consider the real installation and the real heat transfer coefficients. Furthermore, the areas of the thermal parameters have been extended and a special procedure for consideration of vapor superheating has been added (firstly only for one exemplary working fluid HFC 245 fa). For calculations in the superheated area the existing date base [1] has to be extended according to the existing sample.

2 References

[1] S. Smolen, D. Bandean: Working Fluid Selection for Organic Rankine Cycle Applied to Heat Recovery Systems, WREC, World Renewable Energy Congress 2011
Sweden, Linköping, May 2011,



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