Low Energy Transfer Lightweight Roofing System

This article discusses the different low energy transfer roofing systems including convectional, reflective, and radiant strategies. It also highlights their advantages, disadvantages, and installations.

LOW ENERGY TRANSFER LIGHTWEIGHT ROOFING SYSTEM.
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ABSTRACT
In the modern set up, a lot of technologies have been used to improve on the effects of heat on
the comfort of the structures. These technologies include modification of the natural means of
heat transfer. The natural means of heat transfer includes convection, radiation and
conduction.These modifications are tied to the properties of the materials used for building. . The
passive cooling system does not completely eliminate the use of other mechanical means like fan
but it assist in the improvement of the installed structures.
Most of the studies have shown that enhanced means of cooling is through the use of hybrid
system. Roof design with sustainability normally goes beyond the cost but also focuses on the
efficiency of energy consumption. The extent to which the roof affects the environment should
be put into consideration for proper design. These factors will in turn affect the maintenance and
requirements of renewal in the life of the structure.

Contents
A T A TBS R C ....................................................................................................................................................2
T TIN RODUC ION...........................................................................................................................................4
TOBJEC IVES..................................................................................................................................................4
T ATLI ER URE REVIEW....................................................................................................................................5
M T AE HODS ND DISCUSION.........................................................................................................................6
on ectional o ner oo in trateC v L w E gy R f g S gy............................................................................................6
Ad anta ev g s..........................................................................................................................................7
i ad anta eD s v g s......................................................................................................................................8
n tallationI s s.........................................................................................................................................8
e lecti e o ner oo in trateR f v L w E gy R f g s gy...................................................................................................9
Characteristics of the relative approach...................................................................................................9
Ad anta ev g s........................................................................................................................................10
i ad anta eD s v g s....................................................................................................................................10
n tallationI s .........................................................................................................................................10
adiant o ner oo in temR L w E gy R f g sys ....................................................................................................11
Ad anta ev g s........................................................................................................................................12
i ad anta eD s v g s ...................................................................................................................................12
n tallationI s .........................................................................................................................................12
CONCLUSION.............................................................................................................................................13
REFERNCES................................................................................................................................................14

INTRODUCTION
Anybody who has lived on the uppermost floor of any building in the Australia or other parts of
the world with similar climate may have experienced discomfort that results from higher
temperatures especially during the summer seasons. Majority of the buildings in Australia are
built using concrete with flat configurations of tar roofings.These surfaces normally absorb the
incident radiations that are directed to the building. The ceiling that is hot will continue to heat
the available space hence making these places unbearably hot during the day as well as night in
the entire season of winter. ( Tong et al 2014).
In the recent years, these places have undergone improved level of urbanization especially in the
developed countries like Singapore,Indonasia and Malaysia. This increased process of
urbanization has been as a result of the increased population in those areas. The intensity of the
urban heat island commonly known as UHI has also increased. This affect is characterized by the
increase in the consumption of the energy especially the issue of cooling and this is just a
primary concern.
OBJECTIVES
 To highlight the passive cooling strategies and products that are normally used to prevent
the heat gain particularly inside the buildings in Australia and other parts of the world.

The parameters that should be considered in the insulation system, solar shading systems
and other properties like the color on the external surfaces.
 To check on the impacts of the heat that is modulated by the effective solar control so as
to achieve the required balance between the cooling solar gains taking place during the
daylight. This will extend to the evaluation of the structural and architectural
requirements of any building in Australia and other parts of the world. The comfortable
load is therefore given priority in the entire analysis.
 To evaluate the effects of the using the heat sinks through air infiltration. This probably
extends to the properties such as the color of the internal surfaces and also energy
efficient equipment.
LITERATURE REVIEW
The studies that have been carried out by the Building and Construction authority clearly showed
that the structures in the Singapore areas that are also the world fourth leading center of finance
takes up to 57% of the entire consumption of electricity. Also the study showed that the total
house hold consumption of the energy in the whole country was on the increase from 6514GWh
that was in the year 2009 to almost 6560GWh in the year 2011.The economic statistics of the
country has also been shown to be on the increase from every year by at least 15%.The increased
consumption rate was possible owing to the fact the much of the energy is derived from the
fossils fuels.

METHODS AND DISCUSION
The effects or impacts of roofs on the energy consumption has been overlooked more
oftenly.This particular impact can be as well significant if properly utilized. In seasons such as
winter, damages on the roof insulation can results into escape of heat. In summer seasons, heat
that is gained through the roof increases loading on the cooling systems. In order to address these
problems effectively, several options of low energy roofing systems have been utilized in various
section of the world including Australia. Three of these options include; Convectional strategy,
Radiant strategy and reflective strategy.
Convectional Low Energy Roofing Strategy
The results indicated the increased trend in the demand of electricity. The areas of the residence
consumed at least 20% of the total supply. It was also found that at least 21% of this supply is
used in the areas of the air conditioning and also 2% to facilitate or power the mechanical fans.
These figures have been on the increase and this has been a clear indication that Malaysians rely
majorly on the conditioned air sources in order to maintain comfortable working environment.

Figure 1; Convective strategy of roofing system extracted from (Sauna Takebayashi and
Moriyama 2012)
The study of the tropical architecture indicated that most of the Malaysia structures are
constructed using building materials including clay, bamboo and also wood. These materials
have been facing rejection in the new cities that have considered construction using other
materials like shiny metals, glass and also concrete. The close analysis of the environment and
survival conditions indicated that very comfortable structures in Malaysia suffered from the
effects of high temperatures.
Advantages
There has been need to control this high temperature so that the global warming consequences
are brought to control as well. It has been found that the majority of the cooling demands on the
energy in the tropical areas are dependent on the roofing materials. The system of the roofing
represents almost over 70% of the total heat gained. This was the example that was used in the
Malaysia construction. The distribution of the materials were very rational with concrete being

20% and clay being 2.5%.These materials allow for the transmission of solar radiation that
actually induces the effect known as (Sauna Takebayashi and Moriyama 2012).
Disadvantages
The Sauna effects creates environment that is very uncomfortable. One of the approaches that
assist in the maintenance of the right temperature is the strategy of passive cooling. This
particular strategy involves the use of a controller whose primary function is to limit the total
effect of the heat that has been gained. The control effect is that the interior temperatures are far
much below the temperatures of the surrounding. In general terms this practice implies passive
design that is achieved through the natural means( Miranville et al 2012).
These natural mean include conduction, radiation and also convection. The passive cooling
system does not completely eliminate the use of other mechanical means like fan but it assist in
the improvement of the installed structures. Most of the studies have shown that enhanced means
of cooling is through the use of hybrid system. The passive system of cooling normally consists
of the measures that are considered preventive against the effects of overheating in the interior of
the buildings.
Installations
The most commonly used approaches in the area reduce the heat gains and also the temperatures
that are within the building. In order to have all these strategies work effectively and also to
prevent the entry of the excess heat in the building, there are two factors that are required. The
first requirement is a heat sink that has temperature below the interior air (Medina 2012). All
these activities use the earth as the source of cooling( Lee and Lim 2016).Installation cost is
approximately $4500.

Reflective Low Energy Roofing strategy
This strategy is meant to slow down the heat transfer into the building. The studies have
estimated over 60% of the area in the urban set up covered by the roofs and also covered by the
pavements. These figures are on the rise considering that the world’s population tend to
concentrate in the urban centres.The estimation is that by the year 2040,
Figure 2; reflective roofing system extracted from Celsius (Kośny et al 2012).
Characteristics of the relative approach
the figure will hit to over 70%.This will be reflected in the general characteristics of the UHI.The
heat Island intensity has been on the rise to almost 10 degrees Celsius. Effects of the
development of the urban are affected by the quality of the environment in Singapore. The
available reports have indicated that the surface of the air temperature is very high almost 50
degrees Celsius (Kośny et al 2012).
This is a design concept that focuses on the reduction of the effect of the heat gain on the roofs of
the building especially on the sunny days. The design constitutes single or many layers of

different materials. The properties of the physical structures are given major attention in these
cases. The property considered is whether cool or not. They’re very many reasons that are put
forward to support the cool roofs. They promote the indoor thermal or temperature of the spaces
without having air conditioning.Secondly,they1 extend the service life of any roof through
reduction of the roof operating temperatures. There is also aspect of energy reduction in the
consumption units( Gaither et al 2016).
Advantages
Considering that most of the light that is derived from the sun is normally visible, the idea of the
reflective roof works with the surface properties. The reflector is normally targeting the invisible
electromagnetic radiation. These will include both short waves and also long waves. They form
the best emitter of radiations opposed to the black heat that will absorb large amount of heat. It is
interesting to note that a reflective roof under such similar environmental conditions will clearly
maintain the temperature to about 28 degrees Celsius( Asadi, Hassan and Beheshti 2013).
Disadvantages
The properties of the material have been considered key factors. These factors included solar
reflectance. The solar reflectance is also known as albedo. This particular feature focuses on the
reflection of the solar energy especially after it has come into contact with the materials of the
surface. The other key factor of the material response was thermal emittance.This particular
feature focuses on the radiant remittance of heat of a specific object that is in the form of thermal
radiation or just infrared (Ferrari et al.2016).
Installation
The construction and installation need a mechanism that is improved to facilitate the movement
of heat from the hot place to the sink. The above requirement is achievable through use of
environmental sinks of the heat. These environmental heat are divided into four main

cartegories.The transfer of heat by convection is vacillated by the ambient air. There is transfer
of heat by long heat radiation in the atmosphere using very long radiation. There is transfer of
heat by evaporation that takes place in the outside and inside the fabric of the building
(Rodriguez et al .2014). The installation cost is approximately $5400.
Radiant Low Energy Roofing system.
It involves the removal of the unwanted heat from the structure. This particular technique is
based on the fact that any material or object at a particular temperature above 0K will definitely
emit some forms of electromagnetic radiations (Klement, 2012). This is a viable mechanism that
needs to be used considering that more than half of the heat transfer takes place through thermal
radiation. In the concept of radiation, heat will normally flow from the warmer region to the
cooler region. The radiant exchange process has very little impacts on temperatures as opposed
to the natural convection( Arumugam et al. 2015).
Figure 3; radiant roofing system extracted from (Ferrari et al.2016).

Characteristics of the radioactive approach
In the general analysis, net radiation flux is created whenever two different surfaces with
different temperatures face each other. There will be repetition of the processes until the
equilibrium state is achieved. In addition, there will be response from the other surface in case
the other surface becomes cooler. The heat sink exchange operation is based on the temperature
difference between the conditions of the sky and also the component of the building. In practice,
the conditions of the sky plays Avery significant role that affects the radioactive cooling strategy
since air humidy,cloud covers among others like pollution reduces the strategy performance.
Advantages
Most of the known radiant cooling systems can operate both during the day and during the night.
This is because the approach has the best view of the dome of the sky hence the radiator is very
effective. As compared to the conventional methods, radiant cooling systems appear to save on
the cost.
Disadvantages .
However this system has a shortcoming that comes from the accumulation of the dust on the
roofs and this definitely reduces the solar reflectance capacity. The reflectance capacity will keep
reducing as time progresses. Also the radiant method has got very minimal effects on the air
temperature hence will require a strategy for improvement.
Installation
Heat transfers are achieved through conduction beneath the surfaces of the soil. Each of the
building has utilized different ways in the various systems. The heat rejection into these heat
sinks are normally achieved through other methods considered natural done. These natural
means of temperature are normally boosted using mechanical methods that are use of power fans

or just pumps. There has been grouping of the common passive cooling system into comfort
ventilation, radiant cooling, cooling through evaporation means, and nocturnal cooling through
ventilations. The installation of this roofing system utilizes materials whose properties serve the
requirement of the building conditions. The installation cost of the entire system is
approximately $5830.
CONCLUSION
Implementation of receptive and also radioactive approaches in the system of the roofing will
definitely enhance the environmental sinks. This will also facilitate heat dissipation. The result of
this impact is to minimize the effect of the penetration of heat as well as reducing the gains
through lighting and appliances. The efficiency of these structures depends on the type of the
building, the patterns of the occupancy, boundaries of the climate which is subject to air
temperatures, velocity and direction of the wind and also relative humidity.
The effective understanding of the characteristics of the building will always help to improve
the heat rejection from the buildings by natural means. It is important to note that when improper
selection is done on the technique, unpleasant indoor environment will be created. The limitation
in the evaluation tools and also insufficient information will be a draw back to the designer. In
the set up like those of Malaysia, there was no objection in relation to modifications of the roofs
so as to reduce the need for air conditioning. This was a clear indication that the respondent has
been willing to adopt the new cooling strategies for their buildings (Algarni and Nutter 2015).

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