The first task of the pool 1 is to define the monitoring for all the solar cooling processes. Indeed it is important to have the measurement enabling the comparison whatever the running conditions of the installation or whatever the climate. The pool 1 worked out schemes for the measurements of the desiccant and the absorption technologies. In order to evaluate the exergy exchanged during all the processes and to provide a comparison of the three technologies, a first reflection has been carried out to define what should be consider has the reference temperature. The choice has been made first to use a fixed temperature instead of a variable one. Finally the pool 1 proposes to rely on the lowest outside air temperature as the reference temperature [3]. This pool proposes an evaluation of the weather conditions as well. The experimental facilities being located in different climates (tempered in France and tropical in La Reunion), an exergetic analysis of the weather conditions and more specifically of the solar radiation has been carried out to define which technology is suitable for a given climate [4], [5].

4.1. Pole 2

The desiccation process is the key issue of the pole 2; therefore a great effort is made for the modelization of all the components allowing the drying of humid air. This pool has already carried out the validation of a TRNSYS model for the desiccant exchanger (TYPE 882) and another new model, describing the behaviour of a desiccant wheel has been created. It is now possible to propose a simulation of the whole desiccant installation coupled with a building.

4.2. Pole 3

The first results for the pool 3 focus on the simulation of the absorption facilities with EnergyPlus and Simspark. The modelling under EnergyPlus is made following three steps: the first one is to simulate the building without considering the cooling installation in order to validate the physical description of the building. In a second step, the solar cooling installation is modelled considering the solar loop, the storages, the cooling tower and the absorption machine. The last step is to propose a coupling between all this components. However some problems relating to the simulation of the absorption machine connected to the solar collectors still remain. The solution would be to move to the SIMSPARK simulation environment. Two partners of the project have undertaken this work and it should be completed very soon. The first experimental results obtained on the RAFSOL installation show that some modifications can be proposed to reduce the energy consumption of the auxiliaries and consequently improvement of the COP can be achieved.

4.3. Pole 4

The simulation of the thermo chemical installation requires the description of nine main components. Three 3 elements remain to be integrated into the global model before considering the control strategy of the plant. This modelling describes the thermochemical unsteady process thanks to the Gibbs equation systems. As the model includes entropy and exergy calculation for each

component, it is possible to carry out second law analysis and to optimize the process. The experimental facility is used to validate the model and to identify the phenomenological parameters. Moreover, the analysis of the experimental sequences during summer 2007 leads to several improvements of the instrumentation and the control command.

4. Conclusion

This study of the various solar cooling technologies is needed to better understand and control the functioning of these complex processes in order to ensure satisfactory comfort conditions in buildings despite the instability of the energy resource. By providing tools to help design and optimization of the installation, it will be possible to significantly reduce implementation costs and remove a barrier to the widespread dissemination of this technology.

References

[1] M. Clausse, Y. Perigaud, F. Meunier, F. Boudehenn, H. Demasles, (2007). Experimental characterisation of a novel adsorber heat exchanger for dessicant cooling applications. Proceeding of the 22nd IIR International Congress of Refrigeration, august 21th/26th , Beijing, China.

[2] H. Demasles, F. Boudehenn, M. Clausse, (2007). Numerical and experimental studies of a novel adsorber heat exchanger for desiccant solar air conditioning. Proceeding of the 2nd International Conference Solar Air-Conditioning, October 18th/19th, Tarragona, Spain.

[3] M. Pons, (2008). Bases for second law analyses of solar-powered systems, Part 2: the external temperature. , ECOS-2008 21st Int. Conf. on Efficiency, Cost, Optimization, Simulation & Environmental Impact of Energy Systems, Krakow, POLAND, June 24-27 2008, 2008.

[4] M. Pons, (2008). Bases for second law analyses of solar-powered systems, Part 1: the exergy of solar radiation. , ECOS-2008 21st Int. Conf. on Efficiency, Cost, Optimization, Simulation & Environmental Impact of Energy Systems, Krakow, POLAND, June 24-27 2008, 2008.

[5] M. Pons, (2008). Exergie en environnement reel pour la climatisation solaire. Congres Frangais de Thermique, SFT 2008, Toulouse, 3-6 juin 2008.