Nowadays, an important factor for economic and social development is energy sufficiency. Energy is the fuel of growth. Scientist’s predictions show that by the year 2050, energy demand will increase significantly due to the fact of the increasing population of the earth and that more buildings are going to be constructed. (Ref: Facts and trends, energy and climate, world business).
A lot of predictions are published about how fast the population, the economy and the energy consumption of the world will increase in the years and decades to come. In reference to the matter of growth, development and energy demand, most of the predictions were wrongly made. Most predictions are reciprocally dependant on each other, and each one relies on many other factors. However, the only prediction that can be securely made is for the population and that “the growth will be larger in the less development countries than the developed countries”. (UNITED NATIONS) Developed countries are managing to improve the living conditions and decrease the death rates, but at the same time the birth rates have been decreasing at about the same rate over the last century. By this way the population growth is around 0.4% per year, in the industrialized world. On the other hand, less developed countries are managing their development and as a result have increased birth rates and decreased death rates. Consequently, their average population growth has increased from about 1% per year, from fifty years ago to about 2.1% per year today. At the moment, the world’s population is increasing at an annual rate of 1,7%, whereas the population in developed countries is around 1,2 billion (25% of the total) and in less developed countries is around 4 billion (75% of total world population). (United Nations)
Population increases are directly connected with the energy demand and the building sector. It is therefore essential to develop new energy technologies on a massive scale for everyone to be able to survive on this planet. Ordinary buildings are unable to contribute to these essential needs, and cover the gush of the energy demand which is going to follow over the next decade.
Energy use and climate impacts
Power plants use fossil fuels for their energy productions and therefore this way cover the energy demands of the people. As a consequence though, from the burning of the fossil fuels, green house gases are produced and emitted into the atmosphere. As mentioned in the introduction, these anthropogenic activities have a significant contribution to the green house effect and the climate changes.
Generally, in reference to the climate changes issues, scientist’s opinions are split into two. On the one hand, it is believed that the changes are part of the earth’s life and it is something normal which has been accelerated by our human activities and there is a possibility to stabilize the climate changes. On the other hand, it is believed that these changes are not normal and are going to make the world uninhabitable. For this reason, fast and immediate actions should be taken by all countries, targeting to reduce the energy demands and green house gases. It is almost definite that any of these actions will have a deep impact on the economy of each country.
Many people believe that energy saving, means diminishing the current quality of living and reducing economy activity. In addition, economists believe that without economic growth, investments on technology will be reduced as it will difficult to confront climate changes. On the other hand, scientists argue that technological development is the key to the solution in reference to the climate changes problem. The truth is that, any solution in reference to climate changes will need an effort from everyone and investments on technological research and development, giving us this way a chance for a better future!
IPCC’s fourth assessment report further concluded that the building sector is not only the largest potential for significantly reducing greenhouse gas emissions, but also that this potential is relatively independent of the cost per ton of CO2 eqv. achieved. With proven and commercially available technologies, the energy consumption in both new and old buildings can be cut by an estimated 30-50 percent without significantly increasing investment costs. Energy savings can be achieved through a range of measures including smart design, improved insulation, low-energy appliances, high efficiency ventilation and heating/cooling systems, and conservation behaviour from the buildings users. (Reference- IPCC’s fourth assessment report)
Summarising the above it is obvious that the population growth, economic development, human habits, way of living and environmental restrictions influence the energy demand around the world. Scientists and in general, the governments who are trying to give solutions to the big problem of the growing energy demands and its consequences, have to take into account all of these factors.
Reshaping the energy future
It is necessary for all countries to reshape the future of energy, as all scientific researches show. The actual word reshape, includes new innovation technologies and sources which are going to contribute to the energy needs of the world. It is necessary to find new paths which are further environmental friendly and will permit a better future.
A lower carbon world is feasible in the next decade even during the next few years, if all countries can realize that significant changes that should be done. This especially applies to the developed countries as they have to reconsider and find a link between the quality of life and their energy consumption. It is necessary for everyone to understand that a high standard of living does not demand a high consumption of energy and to adapt to the new energy sources.
The good news is that small changes in the energy scenery are now visible as many have started to be influenced. For example, the raised use of gas, the use of renewable energy on buildings, everyday life and high efficiency cars are some of the small steps that have been offered to people due to technological development. As figure three shows, the IPCC scenarios (A1B-AIM and B2-AIM) were based on the new technological achievements in the energy sector. It is definite that this evolution is not enough for our earth’s climate but the two scenarios predict a possible CO2 stabilization. Finally, efforts to create an energy efficient world are starting, in reference to low carbon technologies and effective measures. (Reference-world business …facts and trends on climate change)
As stated in the report of the World Business Council for Sustainable Development (WBCSD) ‘a lower carbon world would require a marked shift in the energy/development relationship, such as similar development levels to be achieved with an average of 30% less energy use. Both energy conservation through behavioural changes and energy efficiency via technology plays a role. Such a trend is a feature of the IPCC B1 storyline, which sees a future with a globally coherent approach to sustainable development. It describes a fast-changing and convergent world toward a service and information economy, with reductions in material intensity and the introduction of clean and resource efficient technologies. The scenario leads to relatively low GHG emissions, even without explicit interventions to manage climate change.'(Reference Energy and climate change, world business)
A Sustainable World Energy Perspective
An important key to the world’s energy problem is sustainable development. Sustainability includes the economic and technological development, which respect and protect the environment. Searching literature for an exact definition of sustainable development, guided us to the ‘The Brundtland Report’ of the UN World Commission on Environment and Development. In this report a definition of sustainable development, is given: ‘Humanity has the ability to make development sustainable – to ensure that it meets the needs of the present without compromising the ability of future generations to meet their own needs’
However it is difficult to find exact definitions which represent the sustainable development accurately, due to the fact that it is an idea which involves too many parameters. (Reference Engineering_for_Sustainable_Development)
It is amazing to see how the sustainable development concept, stays on important issues of discussion even with the passing of tweedy years from the Brundtland report. In this concept, development faces three important paths: the economic, the social and the environmental (figure 4). If governments want to meet these targets it is necessary to carry out innovative technologies and a socio-economic approach.
Nevertheless, sustainable development is not the only problem and therefore it is always important to consider the three major paths. Protection of the environment, economic success and improvement of social conditions, will be the achievements of a flourishing sustainable development. These three paths are linked together for a sustainable development and their integration must be equal without any compromises.
The goal of sustainable development is, to point out the importance of the environment to the public who are now alive and for the coming generations. It is important for everyone to understand that our existence depends on the global environment and every decision of this generation is going to affect the lives of our future generations. Thus for this goal to be achievable, it is necessary to take measures for low green house emissions, use renewable sources and improve the energy consumption of our current lives. Governments and engineers are searching for the best way to come within reach of this goal as it is very difficult for developed and developing countries to achieve it.
Presently, the building sectors involvement is essential because of its deep impact on energy consumption, its significant emissions and its use of huge natural sources. The buildings that currently exist will continue to exist, for more than 30 years and therefore this influences the lives of future generations. A sustainable approach of this sector is necessary due to its rapid growth. The new approach for the buildings sector will include buildings which will need less energy to operate, produce low carbon emissions, use environmental friendly materials and produce their own energy from renewable sources. It is almost definite that the sustainable green development of the building sector will help countries accomplish the targets of the Kyoto Protocol, whilst also guarantee at the same time, the future for coming generations.
Evolution of the buildings and the opportunity for change.
As believed by many, ‘buildings are our third skin’ and this plays an important role for humans to survive. From the beginning of human history, human’s always aimed to try and protect themselves from all weather conditions and all changes, developing due to this, different kinds of shelters. Over the years, human’s adapted and managed to survive all the different changes that have happened on earth. The question now, is what will happen whilst we are facing the rapid climate changes and what will be the future consequences?
Hundreds of thousands year ago, people moved from place to place and tried to create the best conditions to live in. Depending on the place, whether hot or cold, human’s developed different kind of shelters to protect themselves from the heat of the sun in the deserts, or the cold of the northern climates. Studies of these people movements over the years, shows us a big variety of shelters and developments of different ways in order to face the climate conditions.
Other factors, which determine the human’s survival techniques in extreme conditions from the past, like the lower attitude of the Arctic Circle, were the design of the buildings, the quality of clothes and the behavioural adaptations, like changing posture, activity level sand choosing the most comfortable space to occupy, by moving around rooms and buildings and landscapes; and then of course the use of energy from the burning of fossil fuels or the careful use of stored energy in heat or cold stores. (Adapting building & cities for climate change)
Another extraordinary point from past decades is the energy issue. People mainly used coal, wood and water to provide themselves with enough energy, whether in a passive or active manner and covered in this way, their need for heating or cooling. By taking advantage of the natural and available energy resources, humans managed to develop houses which were ready for all extreme weather conditions. All these extreme weather conditions made humans innovate new approaches for buildings, and provide them with a more comfortable life.
An interesting approach of surviving all the climate changes is to move to different areas at the respective time of the year, which is when they are comfortable, and to leave them again when they are not – to migrate. (Adapting building & cities for climate change) This approach is an impossible one to apply, in the modern way of life and the new cities. Nevertheless what could be extracted from the past is the expertise of the ancient people and the way they faced the climate changes. In our day and age, engineers and scientists use the knowledge from the past whilst at the same time search for new innovative approaches for the buildings.
The evolution of the buildings sector involves the innovation of new technologies whilst the same time, protecting the environment and its natural sources. It is not just a matter of how to build or what to build but it is also a matter to make the buildings adaptable to the new challenges of the climate changes and energy efficient. This evolution is directly connected with the world surviving because buildings are part of the global environment which at the moment is in danger.
As written in the book titled ‘Adapting Buildings and Cities for Climate Change’ ‘the risk of not surviving in a particular building type and region will be largely dependent on the nature of that building and on how much the climate changes. Both are crucial in the challenge of designing buildings today in which people can be comfortable in 50 years’ time’.
At the point where the evolution of the building sectors began, there are great opportunities to change the current negative predictions of the climate changes. Significant reductions on energy consumption, better design, adequate technology and appropriate behaviours are some of the keys points which could accomplish the transformation of the buildings sector (figure 7). This transformation needs the participation and contribution from the businesses, the markets, the politicians and engineers. All together, they must act right away because the use of renewable sources is slowly growing and the energy demand is rapidly increasing, setting this way, tight deadlines in order to transform the sector. As it is mentioned in the Energy Efficiency, Buildings report and the IPPC 4th Assessment report, Residential and commercial buildings, ‘action is essential as part of the world’s response to climate change because energy use in buildings is 30-40% of final energy consumption and carbon dioxide emissions in most countries’. (Reference- Energy Efficiency in the Buildings report and the IPPC 4th Assessment report, Residential and commercial buildings)
There are many opportunities to transform the buildings sector into the new era, as well as being feasible and applicable for old and new buildings. Significant energy reductions can be achieved by using new technologies, e.g. energy efficiency appliances, low consumption cooling systems etc, use of renewable sources, better design and operation and use of environmental friendly materials. Using these methods it will be possible to reduce the energy demand of up to two-thirds. ‘Low-energy buildings must become the norm rather than the novelty project’. (Reference- Energy Efficiency in the Buildings report)
Beyond the opportunities given to change the buildings sector and stabilize the climate changes, this transformation will additionally contribute to the economy growth by giving new opportunities for jobs and businesses. (Reference- Energy Efficiency in the Buildings report)As already mentioned, the transformation will only succeed in the case where, building energy becomes a high priority to the governments and businesses leaderships, whilst cooperation between engineers, businesses and authorities is also established in reference to this issue.( Reference- Energy Efficiency in the Buildings report)
Buildings types: characteristics and profiles
Around the world, a vast variety of different types of buildings can be found, and each different type covers multiple and different needs. It is therefore essential at this point, to present the different types of buildings, as this report will focus on the buildings sector and the energy demands. Despite the fact that in the literature review, it is possible to find a plethora of terminology of the building types, nevertheless the general idea of this separation, of the buildings into categories is the same. Usually the separation of the buildings is a result of its use.
It is very important to additionally mention at this point, that in most countries, many of the buildings were built before any energy regulation and these buildings will be around for at least the next 40 years. As figure 8 shows, in Europe, 50% of the buildings were built before 1975.
Residential buildings are commonly found all over the world. However, big and small differences can be found in all of them depending on the climate varieties of each country. For example, in hot climates the important need is for cooling and keeping the temperatures comfortable all over the house. This is achieved by the use of control systems, high insulation materials, shading systems and double or triple glazing. Additionally, this way, the energy demands and cost stays under control. In addition, a high use of passive or active solar systems is found in these hot climate countries. On the other hand, buildings in the cold climates have different needs to achieve temperature comfort. In these climates, the need for heating is essential but this is directly related with other parameters, such as low emissivity windows, good insulation materials and good design. It is very important in these climates, whilst designing, to consider the thermal mass of the building, as this may contribute during the night to the heating. (Low-Energy Building Design Guidelines)
Where residential buildings are concerned, it is easy to use renewable sources and cover the energy needs of a house because the demand is not so big. For example, photovoltaic systems can be used as the main source of energy, minimizing the CO2 emissions and the operation costs of the building.
Non-Residential Buildings are also commonly located all over the world. In contrast with the Residential buildings, these kinds are appropriate for extreme hot or cold climates, without any access to utilities. As it is described in the Low-Energy Building Design Guidelines report of the U.S. Department of Energy these building types ‘have a natural connection with the outdoors; and the structures present an opportunity to interpret the resource-conservation mission of the agency to the visiting public. These structures typically combine a need for window area, massive construction, and a tolerance for temperature swings—all of which are highly compatible with low-energy building design. Day lighting is another key strategy for deployment in these building types’. (Low-Energy Building Design Guidelines)
However, the energy balance of a Non-Residential building is almost independent, from lighting and internal gain. A great opportunity on these kinds of buildings, is to apply the low energy methods and design, due to the fact that such buildings have low energy consumption. A visitor centre is a good example, of this kind of building, and usually they have big budgets allowing the choice of high tech materials and technologies. (Low-Energy Building Design Guidelines)
Urban Office Buildings
Urban office buildings are usually located in the city centres because these buildings offer public services, to the people. As known, urbanization in most countries carries negative consequences for the city centres, for example, expensive land prices.
Due to this fact, the design and use of these buildings must be compact and offer the maximum possible. The use of the building is generally defined by the services that are offered, and the space is then separated into offices and support facilities. (Low-Energy Building Design Guidelines)
Quite frequently, another characteristic of office buildings is their old style, as well as other restrictions, due to the fact that many countries conserve the old buildings in the city centres. Thus the changes for energy conservation or better energy performance on these buildings are limited and therefore it is difficult to apply low energy strategies. In addition, the development of the surrounding area and the high tower new buildings are an important factor, which influence the energy performance of an office building due to the shade provided. (Low-Energy Building Design Guidelines)
On the other hand, new urban office buildings have a great opportunity to save energy as new technologies and design can be afforded and are significant potentials. Another point which helps low energy designs to be applied on office buildings is the wide use of curtain walls, mainly in most of the downtown buildings. The problems which can occur from the use of this kind of buildings is lack of thermal comfort, lack of orientation and the overuse of glass enhance low energy buildings design. New approaches on the office buildings, has started to be applied and they are getting transformed into high technology buildings, which offer better services to the people who work there.
A key factor of successful low energy office buildings is the placement of the private office at the back side of the building. As a result of this design, the artificial lighting will be reduced as natural lights are directed further into the buildings. This will have a significant impact not only for energy demands but also to the HVAC systems. Nevertheless, Urban Office Building’s demand a careful design which takes into account the climate, the orientation, the facade design, the HVAC, shading from the surrounding buildings and the complex interactions amongst lighting. (Low-Energy Building Design Guidelines)
All the above types of buildings constitute the common categories that serve the different human needs. However, there are many subcategories which are adapted specifically for each different climate and different needs.
Energy impacts of the buildings
The energy impacts of a building, is a very important factor to consider, in order to succeed with the design of low energy buildings. The different types of buildings and the differences between their energy demands, is the key for the development of zero energy buildings. As mentioned before, each type of building is designed for a specific use and to cover different needs.
Starting with the residential buildings, studies show us, greater energy consumption than the commercial buildings. The report includes six different regions which are Brazil, China, Europe, India, Japan and the United States. During this report the residential sector is divided into two categories, consisting of the single family and the multi-family buildings, this way being able to focus on the energy performance for each case. (Reference- energy efficiency in buildings –market)
Consumption Survey; Federcasa, Italian Housing Federation (2006), Housing Statistics of the European Union 2005/2006; Statistics Bureau, Ministry of Internal Affairs and Communications (2003), 2003 Housing and Land Survey (Japan); EEB core group research) (Reference- energy efficiency in buildings –market)
As the above figure shows (figure 9), single family buildings are more common in Brazil, India and the United States, in contrast with China, Europe and Japan where the single family buildings are at the same level as multifamily buildings. It is possible that in a few years, this global scenery will change and more multifamily buildings will be required, due to an increasing population of the earth and the growing urbanization in big countries. On the other hand, the development of the countries and economies will allow more people to get richer and own a single family house. (Reference- energy efficiency in buildings –market)
Generally, the residential buildings tend to increase the energy demands all over the world. Unfortunately, the modern way of life “includes” extra comforts which are offered by the high technological appliances and the bigger buildings. As the quality of life increases, the energy consumption grows and more natural sources are needed to cover these human needs. Nevertheless, the energy demand is changing from country to country, as the climate and economy growth, are affecting peoples habits. (Figure 10)
The above graph shows us that in six different regions, the economic growth and the climates have different impacts on the energy consumption of each country. For example, space heating is essential in Europe and China, in contrast with Japan and India where the use is low. Additionally in Japan, water heating is very important, whilst in other countries not so much. Another important point to notice on this graph, is cooking in India, as many areas do not have access to electricity therefore their main energy use, is cooking. (Reference- energy efficiency in buildings –market)
Amongst the residential buildings, one big subcategory is the single family buildings. (Figure 11) All around the world, single family buildings have the greatest impact on energy consumption and CO2 emissions. In the developed countries, people tend to consume more energy at their homes, as they demand more comfort and have bigger spaces, better heating and cooling systems, artificial lighting and use more appliances. For example, whereas in Japan people tend to heat only one of the rooms instead of the whole house, but in Europe they tend to install central heating systems and heat the whole building. All these factors reflect the changes of people’s behaviour, as they become wealthier from the economic growth. It is a fact, that as more people will become wealthier the demand for single family homes will also increase, and the demand will then be greater than today, therefore increasing the energy consumptions. (Reference- energy efficiency in buildings –market)
The issue of reducing consumption in single family buildings is not so simple. In general, all countries encounter serious barriers when it comes to taking effective measures for lower energy consumption. In Europe, many of the buildings that already exist, have an enormous challenge to retrofit these old buildings and apply low energy building principles. Definitely, these changes will cost money and everyone is interested in getting financial backing from the governments. Another issue at hand is to raise awareness, about all the changes that everyone needs to know about, especially with regards to the green technology and the proposed energy solutions which will cover their needs, and be easy to install. Unfortunately until now, the lack of information and financial measures has not helped the development of green technologies and designs for single family houses.
The World Business Council for Sustainable Development mention that ‘there are two key barriers to transforming what is currently a refurbishment market into an energy-efficient market: the first one is that people do not know where to find the relevant information on options, prices and suppliers; there are no “one-stop shops” for retrofitting and the second one is that homeowners base decisions largely on the first cost rather than overall financial returns’. (Reference- energy efficiency in buildings –market)
In developing countries, the biggest problem is the lack of regulations and mechanisms which would then force the people and the market to change. For example, in China the building codes are not effectively applied and in Brazil, 75% of the single homes are “illegally” built. In addition, developing countries as mentioned before have different needs to the developed countries, so the need to provide houses is more essential that the need to reduce energy consumption. (Reference- energy efficiency in buildings –market)
In Japan and the US, the growing population is followed by high rates of constructions. This rapid development of the market causes huge problems to also then apply the green principles on a big scale. Another major problem in these countries is the big differences between the submarket which block, in some ways, the measures of low energy design. The key to the solution in these countries is strengthening their regulations, by giving more information to the public and changing their behaviour. (Reference- energy efficiency in buildings –market)
In the cases of the multifamily buildings, which belong in Residential buildings sector, another approach is necessary for energy efficiency. These types of buildings are commonly located in cities where the urbanization problems are huge. In Europe, the US and Japan these buildings vary from very small to luxury apartments, so the energy demand is also varied. As referred to before, many of the buildings in the centre of the towns were built many years ago, so to achieve energy efficiency and apply the low energy principle is a great issue. In developing countries, incomes influence the preference for bigger houses and more energy consumption, therefore making a multifamily building a key factor for lower energy demand. (Reference- energy efficiency in buildings –market)
Still, comparing single family homes with apartments, obviously the energy needs in an apartment are less due to their small size and space and lower exterior wall area. Looking at the example of the US (figure 12), apartments use almost half the heating energy and lighting energy than a single family house. In general, the energy profile of a single family house is much higher than that of the multifamily building. It is almost definite, that due to the increasing population the living standards in developing countries are growing fast which influences the energy demand. (Reference- energy efficiency in buildings –market)
The office sector in most countries has a significant impact on the energy consumption. These kinds of buildings belong to the commercial buildings sector and they are one of the biggest categories, as they use large amounts of space and energy! The actual buildings, depending on their use, can be found having a great variety, which are from small single buildings to skyscrapers. Usually though, due to the rapid world development which demands more public services, the office buildings are newer rather than older buildings. In China, where technological developments and services increase rapidly, the office sectors are growing rapidly. Additionally, the technological developments influence and change one’s working life as with new high technology, it is easier for some people to work from their homes. The results of these new trends, is the reduction of the floor space needed per person, having fewer large offices and more flexible space. All these factors influence the energy consumption of an office building.
Some other factors that affect the energy demand in office buildings are the same ones as the ones for