Upload
garima-sharma
View
886
Download
11
Tags:
Embed Size (px)
Citation preview
Under the supervision of
Dr. Jaiprakash Bhamu
Associate Professor, DME
Presented by
Garima Sharma
Introduction to Passive Solar
System
What is the meaning of this word “Passive” ?
What is “Passive solar design”?
Passive solar systems rules of
thumb Construction on east-west axis.
Time of receiving sun light during heating season.
Spaces locate on the north.
open floor plan.
shading.
Basic Principles of Passive Solar
Design Passive solar design uses the elements of a building such as
orientation, windows, walls, roof and floors as well as the localizedenvironment to collect, store and distribute solar energy to heat ahome in winter, and block the sun’s heat in summer.
Generally, passive solar design makes use of the following elements:
Orientation
The local environment
Insulation
Energy efficient windows
An absorber
Passive Solar Heating The goal of all passive solar heating systems is to capture the sun's
heat within the building's material and release that heat during
periods when the sun is not shining.
Primary elements of passive solar heating are :
Thermal mass to absorb, store, and distribute heat.
South-facing windows are designed to let the sun's heat in while
insulating against the cold.
Open floor plans allow more sun inside.
There are 3 main methods of passive solar heating:
Direct gain
Indirect gain
Isolated gain
Direct Gain• Living space work as solar collector, heat
absorber and distribution system.
• South-facing windows.
• Use of thermal mass.
(www.azsolarcenter.org)
Indirect Gain Thermal mass place between sun and
space.
Use of flat plat collectors.
(www.azsolarcenter.org)
Isolated Gain
Sunspace
Main functions of sunspaces
Main considerations
Siting
Heat Distribution
Glazing
(www.azsolarcenter.org)
Passive solar cooling Passive cooling systems are least expensive means of cooling a home
which maximizes the efficiency of the building envelope without
any use of mechanical devices.
The primary focus of passive cooling is:
Slow heat transfer into the house.
Remove unwanted heat from the building.
Various passive technologies that can be adopted in the various
climatic zones in India are as follow:
Shading system
Ventilation
Solar chimney
Thermal mass
Wind towers
Evaporative cooling system
2.6.1
Shading system
The most effective method of cooling a building is to shade
windows, walls and roof of building from direct solar radiation.
There are two types of shading system:
External Shading
Internal Shading
External shadingThese method used in external shading:
Eaves
Awnings
Screens and shutters
Louvers
Verandahs
Pergolas
Trees and shrubs
Different kinds of shading
Retractable Awnings
(Maleki,B.A.2011)
Different kinds of shading
(Maleki,B.A.2011)
LouversShade From Pergola
Internal shading•Internal shading can be provided
using curtains and blinds.
Internal shading can be a useful
device when:
• The sun penetrates for only a
short time heat build-up will not
be major problem.
• Windows can he sun be left open
adjacent to them.
• It is required to reduce glare.
(Maleki1, B.A.2011)
Passive solar ventilation
Passive ventilation is when air is exchanged in a building through
openings in the building envelope using the stack and wind
pressures.
These are the passive cooling ventilation strategy:
Cross-Ventilation
Stack Ventilation
Cross-Ventilation
•cross-ventilation
strategies place air inlets
on the windward side and
air outlets on the leeward
side of the home.
(www.level.org.nz)
Stack Ventilation• In stack ventilation cool air
is pulled throughout the home
while warmer air rises above
the cool air to exit through an
opening near the top of the
structure.
(www.level.org.nz)
Thermal Mass A material that has thermal mass is one that has the capacity to
absorb, store and release the sun’s heat energy.
The best way to cool a building is to build with thick stone or
masonry.
Thermal mass is measured in terms of ‘Volumetric heat capacity’.
Thermal mass properties of some material are presented in table
below:
Material Conductivity W/m K
Vol. heat capacity kJ/m3K
Water 1.9 4186
Cast concrete 1.4 2300
Granite 2.1 2154
Brick 0.72 1360
Evaporation cooling• Evaporative cooling lowers indoor air temperature by evaporating
water.
• In evaporative cooling, the sensible heat of air is used to evaporate
water, thereby cooling the air, which, in turn, cools the living space
of the building.
Methods of evaporative cooling include:
• Roof pond systems
• Water spraying
(Guerra, A. 2010)
Solar chimney Improve the ventilation using
convection.
Stack effect,
Black-painted chimney, with a
partly glazed surface area towards
the top.
During the day, solar energy heats
the chimney and the air within it,
creating an updraft of air in the
chimney.
(Pasomarthi)
Wind Towers•In a wind tower, the hot air enters the tower through the openings in
the tower, gets cooled, and thus becomes heavier and sinks down.
(Bahadori, M.N.2006)
Advantage of Passive Solar Design Eliminate heating and cooling costs
Reduce greenhouse gas emissions
Clean process
Eco-friendly
Cost
Attractive living environment
Low maintenance
Unwavering comfort
Disadvantage of Passive Solar Design:- Great deal of work for the engineers to arrange this system.
All systems are not same.
Careful construction required
Improperly designed not work well
Sunshine not available all day
Extra heat and the higher temperatures
Thermal wall loses heat back to the out-of-doors through the glass
Case study of solar passive hostel university of Jodhpur
Wind tower in Jodhpur Hostel to catch favorable cool
wind from south-west for passive cooling
•Glasses
•solid timber shutters
•wind tower
•air gap in the roof
•light colored stone
•South facing windows
Solar Passive Hostel University of Jodhpur(Gupta,V.1992
References Kamal, M.A. (2012), “An Overview of Passive Cooling Techniques in
Buildings: Design Concepts and Architectural Interventions”, Acta
Technica Napocensis: Civil Engineering & Architecture, Vol. 55, No. 1,
pp. 84-97.
Maleki, B.A (2011), “Shading: Passive Cooling And Energy
Conservation In Buildings”, International Journal on “Technical and
Physical Problems of Engineering”(IJTPE), Vol. 3, No. 4,pp, 72-79.
Guerra, A. (2010), “The Roof-Pond or Roof Water A Solar System To
Gain Indirect”.
Bahadori, M.N. (1978); “Passive Cooling System in Iranian
Architecture”, Scientific American, pp.144-154.
Pasumarthi, N., and Sherif, S.A. (2008), “ Experimental And
Theoretical Performance Of A Demonstration Solar Chimney”.
http://www.passivesolar.sustainablesources.com, cited on 12th Jan. 2014.
http://www.azsolarcenter.org, cited on 16th Jan. 2014.
Gupta, V.(1992),“ Solar Passive Hostel University of Jodhpur”,
ARCHITECTURE+DESIGN May-June 1992,pp. 34-35.
Thank You
Questions are Welcome