A THERMO-ECONOMIC COMPARISON OF THE UP-THERM HEAT CONVERTER AND AN ORGANIC RANKINE CYCLE HEAT ENGINE
File(s)
Accepted version
Author(s)
Kirmse, CJW
Oyewunmi, OA
Haslam, A
Markides, CN
Type
Conference Paper
Abstract
In this paper we compare a recently proposed two-phase thermofluidic
oscillator device termed ‘Up-THERM’ to a basic
(sub-critical, non-regenerative) equivalent organic Rankine cycle
(ORC) engine. In the Up-THERM heat converter, a constant
temperature difference imposed by an external heat source and
sink leads to periodic evaporation and condensation of the working
fluid, which gives rise to sustained oscillations of pressure
and volumetric displacement. These oscillations are converted
in a load arrangement into a unidirectional flow, which passes
through a hydraulic motor that extracts useful work from the device.
A pre-specified Up-THERM design is being considered in a
selected application with two n-alkanes, n-hexane and n-heptane,
as potential working fluids. One aim of this work is to evaluate
the potential of this proposed design. The thermodynamic comparison
shows that the ORC engine outperforms the Up-THERM
heat converter in terms of power output and thermal efficiency,
as expected. An economic comparison, however, reveals that the
capital costs of the Up-THERM are lower than those of the ORC
engine. Nevertheless, the specific costs (per unit power) favour
the ORC engine due to its higher power output. Some aspects of
the proposed Up-THERM design are identified for improvement
oscillator device termed ‘Up-THERM’ to a basic
(sub-critical, non-regenerative) equivalent organic Rankine cycle
(ORC) engine. In the Up-THERM heat converter, a constant
temperature difference imposed by an external heat source and
sink leads to periodic evaporation and condensation of the working
fluid, which gives rise to sustained oscillations of pressure
and volumetric displacement. These oscillations are converted
in a load arrangement into a unidirectional flow, which passes
through a hydraulic motor that extracts useful work from the device.
A pre-specified Up-THERM design is being considered in a
selected application with two n-alkanes, n-hexane and n-heptane,
as potential working fluids. One aim of this work is to evaluate
the potential of this proposed design. The thermodynamic comparison
shows that the ORC engine outperforms the Up-THERM
heat converter in terms of power output and thermal efficiency,
as expected. An economic comparison, however, reveals that the
capital costs of the Up-THERM are lower than those of the ORC
engine. Nevertheless, the specific costs (per unit power) favour
the ORC engine due to its higher power output. Some aspects of
the proposed Up-THERM design are identified for improvement
Date Issued
2016-07-11
Date Acceptance
2016-05-09
Copyright Statement
© the authors
Sponsor
EU Commission
Grant Number
FP7-SME-2013/BSG-SME/605826
Source
12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics
Publication Status
Accepted
Start Date
2016-07-11
Finish Date
2016-07-13
Coverage Spatial
Malaga, Spain