1 Copyright © 2012 by ASME
ASME 2012 11th Biennial Conference on Engineering systems Design and Analysis
July 2-4, 2012, Nantes, FRANCE
ESDA2012-82785
SENSITIVITY ANALYSIS OF A SOLAR COOLING SYSTEM
Blaise LETEXIER
PIMENT Laboratory
Saint-Pierre, Reunion Island, FRANCE
Olivier MARC
PIMENT Laboratory
Saint-Pierre, Reunion Island, FRANCE
Jean-Philippe PRAENE
PIMENT Laboratory
Saint-Pierre, Reunion Island, FRANCE
Franck LUCAS
PIMENT Laboratory
Saint-Pierre, Reunion Island, FRANCE
ABSTRACT
The aim of this paper is the optimization of Solar
Absorption Cooling (SAC) system's performances. Over the
past decade the electricity consumption has significantly
increased in Reunion Island during the summer months, which
is mainly due to the use of standard air conditioning systems.
SAC systems present a good alternative for reducing this
consumption. Solar cooling systems are environmentally
friendly as they use water and lithium bromide solution as the
working fluid.
The purpose of this work is to undertake a sensitivity
analysis to identify parameters which have a significant
influence on the SAC systems performances. The sensitivity
analysis has been carried out on numerical models developed at
the PIMENT laboratory and validated using RAFSOL
experimental data (experimental plant is set up at the IUT in St-
Pierre). The results of the sensitivity analysis are used to
establish the design and create the control rules to allow for the
optimization and ensure the performance of future SAC
systems.
Firstly, this paper presents the modelization of the SAC
system and the sensitivity analysis method used. Secondly, it
displays the results from the sensitivity analysis that has been
applied to all main components of the plant separately(solar
collector field, solar loop and absorption chiller) and to the
entire system. Finally, the results are analyzed and discussed.
Two types of influential parameters have been
distinguished: variables factors and geometrical properties of
the plant. This study highlights that the compactness of the
installation, the quality of the solar collector, and the control of
the temperature at the output of the distribution loop are
essential.
INTRODUCTION
During summer in tropical climates, the energy
consumption increase significantly. This augmentation is
mostly due to the use of air conditioning in buildings. In
Reunion Island the cooling of the buildings represent 50% of
the total electricity consumption in summer. A state of art has
been carried out on all the innovative systems set up in
Reunion Island to reduce energy consumption and to produce
renewable energy [1]. Among these systems, the solar
absorption cooling (SAC) represents an interesting alternative
to traditional compression vapor air conditioning. On one hand,
solar energy used in this system has the advantage to be free
and inexhaustible. On the second hand, the cooling needs are
directly dependent to the availability of the solar energy.
Indeed, a rise of the solar radiation will induce an augmentation
of the cooling needs, but in the mean time it will also induce an
augmentation of the cold production.
This work is a part of the MEGAPICS project, which
focuses on the definition of a methodology for performances
guarantees of a SAC system. In order to ensure performances
of solar cooling facilities, a study has been carried out on the
prediction models which have been previously developed at the
PIMENT laboratory. This study is a sensitivity analysis which
allow to ascertain how these models depend of their input
factors. Thus, the parameters which affect the most the
performances of the different components of the facility, could
be determined.
The first part of the paper present the RAFSOL facility and
the numerical model used to undertake the sensitivity analysis.
The second part introduces the two different sensitivity analysis
methods and their implementation. Then, in a third part results
are presented and discussed.