A
WRITE-UP
ON
THE GREEN HOUSE EFFECT AND ITS
IMPLICATION FOR THE DESIGN OF
RESIDENTIAL BUILDINGS IN COMPOSITE
CLIMATES.
PREPARED BY
ABODUNRIN B. B.
ARC/05/5590
Submitted to
PROF O.O. OGUNSOTE
DEPARTMENT OF ARCHITECTURE
FEDERAL UNIVERSITY OF TECHNOLOGY, AKURE.
AUGUST, 2011.
TABLE OF CONTENT
ABSTRACT
CHAPTER ONE
1.0 INTRODUCTION
1.1 Background to the study
1.2 Aim of the study
1.3 Scope of the study
1.4 Definition of terms
CHAPTER TWO
2.0 THE CONCEPT OF GREEN HOUSE EFFECT
2.1 Green house effect in buildings
2.2 Implication of green house effect on residential building designs
2.3 Design of a solar room or green house
CHAPTER THREE
3.0 CONCLUSIONn
REFERENCES
ABSTRACT
The phenomenon of airflow and radiation exchange into and from a building cannot be
over-emphasized as it explains the comfortability of residence of a building. This
culminates into the concept of green house effect in a building.
The critical analysis of the concept of green house effect in residences as it relates mainly
with the composite bio-climatic condition of the environment is vividly envisaged in a clear
context in the write-up.
CHAPTER 1
1.0 INTRODUCTION
Background to the study
The "greenhouse effect" is named by analogy to greenhouses. The greenhouse effect and a
real greenhouse are similar in that they both limit the rate of thermal energy flowing out of
the system, but the mechanisms by which heat is retained are different. A greenhouse
works primarily by preventing absorbed heat from leaving the structure through
convection, i.e. sensible heat transport. The greenhouse effect heats the earth because
greenhouse gases absorb outgoing radiative energy and re-emit some of it back towards
earth.
A greenhouse is built of any material that passes sunlight, usually glass, or plastic. It
mainly heats up because the sun warms the ground inside, which then warms the air in the
greenhouse. The air continues to heat because it is confined within the greenhouse, unlike
the environment outside the greenhouse where warm air near the surface rises and mixes
with cooler air aloft. This can be demonstrated by opening a small window near the roof of
a greenhouse: the temperature will drop considerably. It has also been demonstrated
experimentally that a "greenhouse" with a cover of rock salt (which is transparent to infra
red) heats up an enclosure similarly to one with a glass cover. Thus greenhouses work
primarily by preventing convective cooling.
In the greenhouse effect, rather than retaining (sensible) heat by physically preventing
movement of the air, greenhouse gases act to warm the Earth by re-radiating some of the
energy back towards the surface. This process may exist in real greenhouses, but is
comparatively unimportant there.
Aim of the study
The main aim of this report is to critically envisage the implication of green house effect
on residential building designs in composite climates.
Scope of the study
The study is confined within the limits of green house effect and its concept in buildings
with its implication touching the outer environment analysis of the phenomenon.
Definition of terms
Green house effect: This is a concept in which short term radiation incident on glass is
partly reflected, partly absorbed but mainly transmitted. This is because glass is
transparent to short-wave radiation. Other materials such as concrete or mud absorb the
larger portion of short-wave radiation. The absorbed energy cause a rise in their
temperature and this energy is emitted in the form of long-wave radiation. Glass is opaque
to long-wave radiation and if it encloses the emitter, the heat is trapped within the
enclosure leading to a temperature rise within the enclosure known as the green house
effect.
Composite climate: These are characterized by alternating hot dry, cold dry and warm
humid seasons with their building elements design depending on the duration of the
seasons.
CHAPTER 2
2.0 THE CONCEPT OF GREEN HOUSE EFFECT
The greenhouse effect is a process by which thermal radiation from a planetary surface
is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions. Since
part of this re-radiation is back towards the surface, energy is transferred to the surface
and the lower atmosphere. As a result, the temperature there is higher than it would be if
direct heating by solar radiation were the only warming mechanism.
Solar radiation at the high frequencies of visible light passes through the atmosphere to
warm the planetary surface, which then emits this energy at the lower frequencies of
infrared thermal radiation. Infrared radiation is absorbed by greenhouse gases, which in
turn re-radiate much of the energy to the surface and lower atmosphere. The mechanism is
named after the effect of solar radiation passing through glass and warming a greenhouse,
but the way it retains heat is fundamentally different as a greenhouse works by reducing
airflow, isolating the warm air inside the structure so that heat is not lost by convection.
The greenhouse effect was discovered by Joseph Fourier in 1824, first reliably
experimented on by John Tyndall in 1858, and first reported quantitatively by Svante
Arrhenius in 1896.
If an ideal thermally conductive blackbody was the same distance from the Sun as the
Earth is, it would have a temperature of about 5.3 °C. However, since the Earth reflects
about 30% (or 28%) of the incoming sunlight, the planet's effective temperature (the
temperature of a blackbody that would emit the same amount of radiation) is about −18 or
−19 °C, about 33°C below the actual surface temperature of about 14 °C or 15 °C. The
mechanism that produces this difference between the actual surface temperature and the
effective temperature is due to the atmosphere and is known as the greenhouse effect.
Green house effect in buildings
The concept of green house effect in residential buildings cannot be over-emphasized as
it borders about the modern trend of heat generation and removal within a building in a
composite climatic conditioned zone. Short wave radiations that are allowed to pass
through the glass window panels are converted to long-wave radiation after increasing the
temperature of a contact source e.g. concrete which is also high in temperature and are
retained in the building interior due to the non-allowance of long-wave radiation
transmission through an opaque material like glass. This concept is however very vital as it
inherently aids different variety of usage in a composite bio-climatic environment with
constantly changing whether characterizing different seasons and the effect is more needed
during the cold dry and warm humid seasons.
However, some of the factors that can affect the green house concept in buildings are:

Type and property of fenestration material.

Shape size and position of fenestration.

Property of the radiation absorbing material n the interior.

Size of the interior space.

Speed of radiation.
Implication green house effect on residential building designs
This cannot be farfetched as the implication is vividly envisaged in the variety of
applicability of the green house effect concept in developing a sustainable design that is
less energy consuming as regarding rating system and a basis for innovative technologies
useful in modern residential building design approaches.
However, the green building system is a concept stemmed out of the necessity to create
structures and use environmentally responsible and resource efficient processes
throughout a building’s life cycle starting from the design, construction and maintenance.
The practice will enhance durability, comfort, utility and economy of the building design as
needed and necessitated by the green house concept. It often emphasizes taking advantage
of renewable resources such as sunlight through passive solar and active solar techniques
which is the common modern trend been followed now in the developed world. The
essence of green building is to ensure optimization of one or more of the principles
governing proper synergistic design, individual technology may work together to produce
its greater cumulative effect.
Design of a solar room or green house
The application of the green-house effect concept is exemplified in the design of a solar
room or green house.
Solar greenhouses and sunrooms share some common design features. To design a
solar room or greenhouse, you need to understand the greenhouse effect, which occurs
when sunlight enters the enclosed space through the glazing (window) and then gets
absorbed and stored as heat energy. The heat is then constrained to stay in the enclosed
space via the same glazing's insulation properties, plus insulation in the walls. You can
enhance the greenhouse effect by increasing the amount of radiation the windows allow to
enter while maximizing the glass's insulation against heat.
Fig 1: The greenhouse effect traps heat
Source: http//www.dummies.com//how to design solar houses
When air heats, it becomes lighter, so the hot air rises, making the air in a room warmer
near the ceiling than the floor. The phenomenon is called the ‘’CHIMNEY EFFECT’’.
Most solar rooms include vents that open or close to take advantage of the chimney
effect. When the solar room is warmer than the house, the vents open, allowing heat from
the sunroom to enter the house (vice versa at night or on cold winter days). Or when the
room's just too hot, you can completely close off the space from the rest of the house.
Fig 2: Air warms in the sunroom, rises, and enters the house through the vent; inside, air cools, sinks,
and then returns to the sunroom for reheating.
Source: http//www.dummies.com//how to design solar houses
Vent fans can enhance the chimney effect. Solar-powered ceiling fans work well because
they don't need to be hard-wired, plus they work hardest when the sun is hottest, which is
usually what you want.
There are a million ways to build a solar room, but some practical generalizations can
ensure a successful project. The transparent cover (also referred to as glazing or windows)
allows for sunlight entry. The rock pile is thermal mass, which stores heat and serves to
regulate a consistent temperature in the space. A reflective wall lining is optional; it serves
to reflect sunlight down onto the thermal mass and plants.
As with all solar projects, kits are the best bet for the do-it-yourselfer, and a big industry
is dedicated to manufacturing and selling prefabricated kits.
Fig 3: Solar rooms have the same basic components as greenhouses.
Source: http//www.dummies.com//how to design solar houses
As with all solar systems, a collector, or transparent cover, allows sunlight to enter. The
larger the area, the more energy captured. You can control seasonal and daily variation by
orienting the collector's east/west direction (azimuth) and altitude (upward angle toward
the sky).
Commercial greenhouses are usually made with glass ceilings, but you can get the same
open effect by angling the window glass.
Double-pane glass works well as a collector, and a number of window coatings and other
optical engineering methods can also work to good effect because they allow light to pass
through but also insulate for heat.
Greenhouses often have solar reflectors mounted into their roofs in the summer because
there's too much sunlight. You can choose from a range of clever movable insulation
methods, such as a blind mechanism loaded with radiant barrier reflective material. Hoods,
overhangs, and awnings can also control the seasonal and daily variation of sunlight.
Window blinds are often used in solar rooms to prevent heat escape at night, to keep the
room from getting too hot in the summer, or to enhance privacy. They also make the room
much more attractive.
After the sunlight enters the space, an absorber captures the energy and transforms it
into heat. Dark, rough surfaces, such as gravel floors in a greenhouse or dark furniture and
carpet in a sunroom, work best.
Rocks are cheap for building thermal mass, and water is a good choice because it's
cheap, holds heat, and is readily available. For maximum functional effect, drums filled with
water may be painted black and set in the direct sunlight. Sunrooms don't require as much
thermal mass because you can close them off from the house when needed. Concrete floors
are good solutions because they provide not only mass but also a good, solid underpinning
to the room.
CHAPTER 3
3.0 CONCLUSION
The green house effect as a concept is gaining prominence in its utilization and imbibing
its techniques in putting forward design approaches which will favorably ensure the
comfort of residential building occupants in a constantly changing composite climate as we
have in Nigeria. This is evident in the phenomenon of green building rating system as
discussed in the context of the write-up and as suggested by the applications as solar house
design, green housing, e.t.c. New technologies are constantly being developed to
complement current practices in creating greener structures, with the common objective is
been reducing the overall impact of the built environment on human health and natural
environment by:

Efficiently using energy, water and other resources.

Protecting occupant’s health and improving employees’ productivity.

Reducing waste, pollution and other environmental degradation.
REFERENCES
http// www.wikipedia.com//greenhouse: Accessed on 30th August, 2011.
http// science direct//green house effect: Accessed on 30th August, 2011.
http// www.greenit.com//yesil yasam sitesi//eco-friendly environment: Accessed on
30th August, 2011.
http//www.dummies.com//how to design solar houses: Accessed on 3oth August, 2011.
OGUNSOTE O.O. (1993): Applied climatology; a compilation of lecture notes on Arc 810,
lecture series for M.Tech architecture.