SOLNET at Polimi Development and optimisation of a novel desiccant and evaporative system for solar air conditioning

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SOLNET at PolimiDevelopment and optimisation of
a novel desiccant and evaporative system for
solar air conditioning
Alexandra Lozano Tormo Dipartimento di
Energetica - Politecnico di Milano Lyngby,
Denmark, October 10th 2007
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Contents

• SOLNET PhD project at Politecnico DO of a novel
  DEC system for solar air conditioning
• ECOS Physical System parametrical overview
• COMSOL cooling channel model
• Current Status Tasks developed
• Milestones planning
• References

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PhD project Development and optimisation of ECOS
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PHYSICAL SYSTEM parametrical overview
SORPTIVE CHANNEL
COOLING CHANNEL
Regeneration T 60-90ºC
Source MSc thesis of Francesco Besana, Univ.
Bergamo, 7/10/2004 Ref. 3.
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PHYSICAL SYSTEM parametrical overview
Conductive Heat transfer
Convective Heat transfer
Phase change latent Cp
PARAMETERS u,v velocity components x humidity
ratio
T Temperature k medium permeability µ
viscosity
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COMSOL model of cooling channeldry air and
forced boundary conditions (BC) for latent heat
Main hypothesis
Model definition
Domain settings BC
Meshing
Laminar Incompressible Navier-Stokes
Settings control
Numerical control
Results analysis
Convergence monitoring
Simulations Error analysis
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Current Status Tasks developed

• Literature survey on ECOS technology, sorption
  processes materials
• Tasks coordination and 1st meeting with
  Fraunhofer-ISE
• CFD analysis introduction, evaluation
  selection of CFD tool. COMSOL acquisition
  getting started - Seminars
• Preparation assistance to 3 Solnet 3
  Politecnico Courses Task38 IEA-SHPC (France)
• First work visit 1 week at Fraunhofer Institute
  for Solar Energy Systems
• Development of 2D model of ECOS cooling channel
  CFD literature survey
• Convergence checking and model adjustments
• TO be FINISHED by the end of 2007
• Cooling channel simulations 2 Politecnico
  courses CFD Exam CFD Project Scuola
  Dottorato Thesis exam Trnsys Project CERC
  (Solnet)

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MILESTONES PLANNING
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PHYSICAL SYSTEM parametrical overview
Energy mass balance
Darcys law
Cmet metal plate Heat capacity Csorp Sorp.mat. H
capacity
Metal plate
Sorption material
Navier-Stokes eqs
Sorptive channel
u0,v0, x0, T0
u1,v1, x1, T1
Conductive Heat transfer
xM, TM
Convective Heat transfer
Cooling channel
u2,v2, x2, T2
uf,vf, xf, Tf
Vaporisation saturated air (water thin layer)
Phase change latent Cp
PARAMETERS u,v velocity components x humidity
ratio
T Temperature k medium permeability µ
viscosity
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References

• Experimental simulation study on the kinetics
  of water vapour adsorption on different kinds of
  adsorptive material matrices Schnabel and
  Henning, 2005.
• Experimental characterisation Dynamic modelling
  of MHT in Water-Zeolite adsorption process (D.
  Boruah master thesis, 2007)
• PhD thesis of Francesco Besana, Politecnico di
  Milano, 7/10/2004
• M. Motta, H.M. Henning - A novel high efficient
  solar assisted sorption system for air building
  air-conditioning (ECOS) cycle performance and
  potential application. ESTEC 2005.
• Henning H.M., (2004) Hans-Martin Henning (Ed.)
  Solar-Assisted Air-Conditioning in Buildings, A
  handbook for planners - (2004) Springer Verlag
• Motta M. et al. (2004) M. Motta, H.M. Henning -
  An original heat driven air-conditioning concept
  advanced desiccant and evaporative cooling cycle
  numerical analysis, Proc. 44 Convegno
  Internazionale AICARR 2004 Milano 3-4 Marzo
  2004 Vol.II p. 1149 - 1166.
• Motta M. et al. 2 (2004) - M. Motta, H.M. Henning
  - Performance analysis of a novel desiccant and
  evaporative cooling cycle - - Proceedings of the
  3rd International Conference on Heat Powered
  Cycles, HPC2004 October 2004 in Larnaca in Cyprus
• Motta M. et al. 3 (2004) - M. Motta, H.M. Henning
  - An advanced solar assisted sorption cycle for
  building air-conditioning the ECOS potential and
  performance assessment - Proceedings of the 14.
  International Sonnenforum, Eurosun 2004, Freiburg
  (Germany)

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COMSOL model of cooling channeldry air and
forced boundary conditions (BC) for latent heat
Air
Heat removal (Phase change latent Cp from water
vaporisation)
Convective Heat transfer fixed heat source. When
coupling both sorptive and cooling channels, it
will be flowing from the sorptive one.
Supply airVolume flow rate 200m3/s
return air26C
u2,v2, x2, T2
uf,vf, xf, Tf
BC Heat transfer from sorption channel.
BC water evaporation latent heat transfer
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ECOS pre- and post-treatment components
Source M. Motta et al. Ref. 6
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Overview of solar cooling processes
Source Master thesis of D. Boruah, Fraunhofer
Institut, Freiburg, 19/1/2007.