The Impact of Hospital Intensive Care Unit Window Design on Daylighting and Energy Performance in Desert Climate

This paper addresses the design of hospital Intensive Care Unit windows for the achievement of visual comfort and energy savings. The aim was to identify the window size and shading system configurations that could fulfill daylighting adequacy, avoid glare and reduce energy consumption. The study focused on addressing the effect of utilizing different shading systems in association with a range of Window-to-Wall Ratios (WWR) in different orientations under the desert clear-sky of Cairo, Egypt. The results of this study demonstrated that solar penetration is a critical concern affecting the design of ICU windows in desert locations, as in Cairo, Egypt. Use of shading systems was found to be essential in providing acceptable daylight performance and energy saving. Careful positioning of the ICU window towards a proper orientation can dramatically improve performance. It was observed that ICU windows facing the north direction enjoyed the widest range of successful window configuration possibilities at different WWRs. ICU windows facing south enjoyed a reasonable number of configuration options as well. By contrast, the ICU windows facing the east orientation had a very limited number of options that provide acceptable performance. These require additional local shading measures at certain times due to glare incidence. Moreover, use of horizontal sun breakers and solar screens to protect the ICU windows proved to be more successful than the other alternatives in a wide range of Window to Wall Ratios. By contrast, the use of light shelves and vertical shading devices seemed questionable.

Authors:

• A. Sherif
• H. Sabry
• A. Elzafarany
• M. Gadelhak
• R. Arafa
• M. Aly

Keywords:

• Daylighting
• Desert
• Energy Efficiency
• Shading.

References:

[1] FGI, Guidelines for Design and Construction of Hospitals and
Outpatient Facilities. USA: The Facility Guidelines Institute, 2014.
[2] M. M. Shepley, R. P. Gerbi, A. E.Watson, S. Imgrund, and R. Sagha-
Zadeh, “The impact of daylight and views on ICU patients and staff,”
Health Environments Research & Design Journal (HERD), vol. 5, no. 2,
pp.46-60, 2012.
[3] R. Ulrich, X. Quan, C. Zimring, A. Joseph and R. Choudhary, “The role
of the physical environment in the hospital of the 21st century: a oncein-
a-lifetime opportunity,” The Center for Health Design SM, 2004.
[4] S. Pornkrisadanuphan and P. Chaiwiwatworakul, “A Genetic Algorithm-
Based Approach Design for Energy-Efficient Building in Thailand,” In
Proc. of the International Conf. on Environment Science and
Engineering (IPCBEE), Singapore, 2011.
[5] H. Alzoubi and A. Al-Zoubi, “Assessment of building façade
performance in terms of daylighting and the associated energy
consumption in architectural spaces: Vertical and horizontal shading
devices for southern exposure facades,” Energy Conversion and
Management, vol. 51, pp. 1592-1599, 2010.
[6] A. Sherif, H. Sabry and T. Rakha, "External perforated Solar Screens
for daylighting in residential desert buildings: Identification of minimum perforation percentages," Solar Energy, vol. 86, no. 6, pp. 1929–1940,
2012-a.
[7] A. Sherif, H. Sabry and M. Gadelhak, "The impact of changing solar
screen rotation angle and its opening aspect ratios on Daylighting
Availability in residential desert buildings," Solar Energy, vol. 86, no.
11, pp. 3353–3363, 2012-b.
[8] A. Sherif, A. Zafarany and R. Arafa, “Energy simulation as a tool for
selecting window and shading configuration in extreme desert
environment- Case Study: Intensive Care Unit in Aswan,” In Proc. of the
Sustainable Building Conf. (SB 2013), Cairo, Egypt, 2013-a.
[9] A. Sherif, H. Sabry and M. Gadelhak, “Daylighting simulation as means
for configuring hospital intensive care unit windows under the desert
clear skies,” In Proc. of the Building Simulation Conf. (BS 2013),
Chambéry, France, 2013-b.
[10] Time and Date AS, “Sunrise and sunset in Cairo,” (Time and Date AS)
(Online), Available: http://www.timeanddate.com/worldclock/
astronomy.html?n=748 (Accessed 15 Dec. 2012), 2012.
[11] D. DiLaura, et al, The Lighting Handbook: Reference and Application,
New York (NY): Illuminating Engineering Society of North America,
2011.
[12] C. F. Reinhart and J. Wienold, “The daylighting dashboard -A
simulation-based design analysis for daylit spaces,” Building and
Environment, vol.46, pp. 386-396, 2011.
[13] J. Wienold, “Dynamic daylight glare evaluation,” In Proc. of Buildings
Simulation 2009, 2009.
[14] J. Wienold and J. Christoffersen, “Evaluation methods and development
of a new glare prediction model for daylight environments with the use
of CCD cameras,” Energy and buildings, vol. 38, no.7, pp. 743-757,
2006.
[15] Climate and Temperature 2013. “Climate of Cairo, Egypt: Average
Weather” Available: http://www.cairo.climatemps.com/ (Accessed 27
December 2013).