Numerical and experimental investigations of diffusion absorption refrigeration systems for use with low temperature heat sources
File(s)
Accepted version
Author(s)
Najjaran Kheirabadi, Ahmad
Harraz, Asmaa A
Freeman, James
Mac Dowell, Niall
Markides, Christos N
Type
Conference Paper
Abstract
he diffusion absorption refrigeration (DAR) cycle is a technology
of increasing interest thanks to its
suitab
ility
for
providing
cooling from
a
thermal energy
input
in a range of applications
. It
can be
distinguished from other
absorption refrigeration cycles by
its employment
of a thermally
-
driven bubble pump to
circulate the working fluid
,
which gives it an
ability to operate
entirely off
-
grid
without an electricity input
. In this work
,
we present
results from
an experimental
campaign aimed at
characteri
s
ing
the performance of a
prototype
ammonia
-
water
-
hydrogen
D
AR system
with a
nominal cooling
capacity of 100 W,
over a range of operating conditions,
specifically with a
view of
adapt
ing
the
system
for use in low
-
temperature applications. In the experiments,
the
heat input to the
DAR generator is provided over a ra
ng
e of temperatures
from
175
to
215
°C
by
using electrical cartridge heaters.
The system is charged to 22 bar, and the ammonia mass concentration of the working fluid mixture is 30%. The
resulting
coefficient of performance (COP) of the system is measured in the range
0.12
to
0.26
.
A new
methodology for the selection of optimal working
-
fluid mixtures using the state
-
of
-
the
-
art, statistical associating
fluid theory (SAFT) approach implemented within
the process modelling software gPROMS
®
is also presented.
The experimental results
will be used for future
validation of a thermodynamic model of the cycle.
Finally,
the
performance of the system in a solar application is investigated, with
a
thermal input
provided by an array of
evacuated tube heat pipe solar collectors. The system pressure and condensation temperature are found to be
key factors in determining the performance of solar
-
DAR system
s
.
of increasing interest thanks to its
suitab
ility
for
providing
cooling from
a
thermal energy
input
in a range of applications
. It
can be
distinguished from other
absorption refrigeration cycles by
its employment
of a thermally
-
driven bubble pump to
circulate the working fluid
,
which gives it an
ability to operate
entirely off
-
grid
without an electricity input
. In this work
,
we present
results from
an experimental
campaign aimed at
characteri
s
ing
the performance of a
prototype
ammonia
-
water
-
hydrogen
D
AR system
with a
nominal cooling
capacity of 100 W,
over a range of operating conditions,
specifically with a
view of
adapt
ing
the
system
for use in low
-
temperature applications. In the experiments,
the
heat input to the
DAR generator is provided over a ra
ng
e of temperatures
from
175
to
215
°C
by
using electrical cartridge heaters.
The system is charged to 22 bar, and the ammonia mass concentration of the working fluid mixture is 30%. The
resulting
coefficient of performance (COP) of the system is measured in the range
0.12
to
0.26
.
A new
methodology for the selection of optimal working
-
fluid mixtures using the state
-
of
-
the
-
art, statistical associating
fluid theory (SAFT) approach implemented within
the process modelling software gPROMS
®
is also presented.
The experimental results
will be used for future
validation of a thermodynamic model of the cycle.
Finally,
the
performance of the system in a solar application is investigated, with
a
thermal input
provided by an array of
evacuated tube heat pipe solar collectors. The system pressure and condensation temperature are found to be
key factors in determining the performance of solar
-
DAR system
s
.
Date Issued
2018-06-17
Date Acceptance
2018-05-04
Citation
ECOS 2018 - 31st International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, 2018
Publisher
ECOS
Journal / Book Title
ECOS 2018 - 31st International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems
Copyright Statement
© 2018 The Author(s)
Sponsor
Engineering & Physical Science Research Council (EPSRC)
Engineering & Physical Science Research Council (EPSRC)
Engineering & Physical Science Research Council (EPSRC)
Grant Number
EP/M025012/1
EP/P004709/1
EP/P030920/1
Source
ECOS 2018 - 31st International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems
Publication Status
Published
Start Date
2018-06-17
Finish Date
2018-06-21
Coverage Spatial
Guimarães, Portugal