Document Type : Research Paper


Electromechanical Engineering Dept, University of Technology-Iraq, Alsina’a Street, 10066 Baghdad, Iraq.


Window solar air collector is an imperative instrument for heating residential buildings in cold regions. This paper presents a numerical investigation of the thermal performance of a window solar air collector with seven moveable absorber plates. With glass on the front and back sides of the collector. By the use of FORTRAN 90; The three-dimensional steady-state turbulent forced convection method was used to solve the Navier-Stokes equations. The seven plates opened and closed at different angles in unison manually by a specific mechanical mechanism. The effect of changing the plate angles has been tested, alongside the effect of airflow rates and the intensity of solar radiation. Numerical results illustrate that air temperature difference is higher at vertical plates position (angle 0) compared to that at angle 90. In contrast, flexibility between sunlight penetrating the room and hot air from the collector will be gained when the plates are set on angle 90. Results indicate that the thermal performance was improved by 67% when the plates were set at angle 0. Maximum thermal efficiency for angle 0 was 72% at a mass flow rate of 0.0298 kg/s. However, maximum thermal efficiency was 51% at mass flow rate 0.0298 for angle 90°.

Graphical Abstract


  • A new novel window with 7 movable absorber plates with different opening angles.
  • Best thermal performance and minimum of sunlight were obtained at angle 0.
  • Lower thermal performance and maximum of sunlight were obtained at angle 90.
  • A flexibility between hot air and sunlight requirements for angles between 0 and 90.


Main Subjects

[1] A. S. Bejan, A. L., C. Croitoru1* and T. Catalina, Air solar collectors in building use - A review E3S Web of Conferences 32, 01003, 32(2018).
[2] M. Sandberg, and B. Moshfegh, Investigation of fluid flow and heat transfer in a vertical channel heated from one side by PV elements, part I-Numerical study, J. Renewable Energy, 8 (1996) 248-253.
[3] J. Phillips, D. Naylor, P. H. Oosthuizen, and S. J. Harrison, Numerical study of convective and radiative heat transfer from a window glazing with a venetian blind, HVAC & R Research, 7 (2001).
[4] L. Liao, A. K. Athienitis, L. Candanedo, K. W. Park, Y. Poissant, and M. Collins, Numerical and experimental study of heat transfer in a BIPV-thermal system, Sol. Energy Eng., 129 (2007) 423-430.
[5] J. Han, L. Lu, and H. Yang, Numerical evaluation of the mixed convective heat transfer in a double-pane window integrated with see-through a-Si PV cells with low-e coatings, ACS Appl. Energy Mater , 87 (2010) 3431-3437.
[6] X. Li, C. Li, and B. Li, Net heat gain assessment on a glazed transpired solar air collector with slit-like perforations, Appl. Therm. Eng, 99 (2016) 1-10.
[7] J. M. Jalil, A. H. Reja, and A. M. Hadi, Numerical Investigation of Thermal Performance of Micro-Pin Fin with Different Arrangements, IOP Conference Series: Materials Science and Engineering, 765 (2020) 012037, IOP Publishing.
[8] G. Michaux, R. Greffet, P. Salagnac, and J. B. Ridoret, Modelling of an airflow window and numerical investigation of its thermal performances by comparison to conventional double and triple-glazed windows, ACS Appl. Energy Mater, 242 (2019) 27-45.
[9] Y. Hu, P. K. Heiselberg, H. Johra, & R. Guo, Experimental and numerical study of a PCM solar air heat exchanger and its ventilation preheating effectiveness, J. Renewable Energy, 145 (2020) 106-115.    
[10] H. K. Versteeg and W. Malalasekera, An introduction to computational fluid dynamics: the finite volume method, Pearson education, second ed, uk, (2007).
[11] N. I. Dawood, J. M. Jalil, and M. K. Ahmed, Experimental Investigation of a Window Solar Air Collector with Circular-Perforated Moveable Absorber Plates, the 3rd int. Scientific conference of Eng. Sciences and advances technologies (IICESAT), Iraq, (2021), Paper 83, Unpublished.