Evaluation of a solar cooling system with louvre thermal collectors
International Journal of Low Carbon Technologies 2/2
Evaluation of a solar cooling system with louvre thermal collectors
Ana I. Palmero-Marrero 0
Armando C. Oliveira (corresponding author) 0
0 Faculty of Engineering, University of Porto, Dept. Mechanical Engineering and Industrial Management , Rua Dr. Roberto Frias, 4200-465 Porto , Portugal
This work aims to evaluate the integration of solar louvre collectors into a cooling system using a water-fired absorption chiller. Simulations for a building were performed using the TRNSYS simulation program, varying collector areas and using Portuguese climatic conditions. The system performance was assessed and the results show that with such a system, comfortable indoor thermal conditions can be guaranteed. The system may also lead to energy savings when compared with conventional cooling. Roman letters A area [m2] COP chiller coefficient of performance [−] f solar fraction [−] F collector heat removal factor [−] (based on collector average fluid temperature) H height [m] l, L length [m] Q monthly thermal energy [J, kWh] T temperature [°C] UL collector heat loss coefficient [W/m2/K] Greek letters h efficiency [−] (ta)n collector transmittance - absorptance product for normal incidence [−] c louvre inclination angle [°]
solar collectors; louvres; absorption cooling; building simulation; TRNSYS
Nomenclature
Subscripts
air indoor air
amb ambient air (external)
aux auxiliary
cool cooling
col collector (louvre)
e collector edge to façade
hw hot water
inc incident
Introduction solar useful window
transparent plastic
louvre insert
SOLAR RADIATION
copper louvre insert
(water channel)
louvre
insulation aluminium frame
solar louvres
windows in
south façade
solar louvre
collectors
χ
Le = 1.11 m
Lw = 1.5 m
H = 0.87 m
lcol = 0.25 m
S
Le
H
Hw
Modelling of system components
Simulation results
without shad.
with shad.
with shad. + chiller
Acol =12.5 m2
without shad.
with shad.
with shad. + chiller
Acol = 25 m2
with shad. Tamb
with shad. + chiller
Hours
Qhw
Qcool
Qaux Qsoll usef
Acol = 12.5 m2
Months
Figure 9.
COP = Qcool
Qhw
f = Qsol usef = 1 − Qaux
Qhw Qhw
hsol =
Qcool Qsol inc
Qcool (MJ)
Qcoo (MJ)
Qaux = (1 − f ) ⋅ Qhw =
Qcool
Acol
Qcool
Celect.(€/year)
(at 0.115 €/kWh)
Cnat.gas.(€/year)
(at 0.0717 €/kWh)
savings
(€/year)
Acknowledgment
[1] S. B. Riffat , ' Solar Louvre Building Integrated Collector. Final Technical Report to the European Commission' , contract ENK6 - CT2000 -00330, ( 2003 ).
[2] A. I. Palmero-Marrero and A. C. Oliveira , 'Evaluation of a Solar Thermal System Using Building Louvre Shading Devices', Solar Energy , 80 ( 5 ) ( 2006 ), 545 - 554 .
[3] A. I. Palmero-Marrero and A. C. Oliveira , ' Testing of an Integrated Solar Louvre Collector', International Journal of Ambient Energy , 25 ( 4 ) ( 2004 ), 171 - 176 .
[4] M. Safarik , L. Richter and M. Otto , Solar Powered H2O/LiBr Absorption Chiller with Low Capacity' , Proceedings HPC ' 04 (Heat Powered Cycles) Conference, London South Bank Univ., Cyprus, 2004 .
[5] A. A. Argiriou , C. A. Balaras , S. Kontoyiannidis and E. Michel , ' Numerical Simulation and Performance Assessment of a Low Capacity Solar Assisted Absorption Heat Pump Coupled with a SubFloor System' , Solar Energy, 79 ( 3 ) ( 2005 ), 290 - 301 .
[6] Solar Energy Laboratory , ' TRNSYS 16: A Transient System Simulation Program - Program Manual' , ( 2004 ), University of Wisconsin-Madison, USA.
[7] Meteotest , 2003 . Meteonorm Handbook, Parts I, II and III . Bern, Switzerland. (http://www. meteotest.ch)
[8] ISO-7730, 'Moderate thermal environments. Determination of the PMV and PPD indices and specification of the conditions for thermal comfort' , International Standards Organisation, ( 1994 ). (...truncated)