A review on buildings energy consumption information

TL;DR: In this article, the authors analyzed available information concerning energy consumption in buildings, and particularly related to HVAC systems, and compared different types of building types and end uses in different countries.

About: This article is published in Energy and Buildings.The article was published on 2008-01-01 and is currently open access. It has received 5288 citations till now. The article focuses on the topics: Energy consumption & Zero-energy building.

Summary

Introduction

• The rapidly growing world energy use has already raised concerns over supply difficulties, exhaustion of energy resources and heavy environmental impacts (ozone layer depletion, global warming, climate change, etc.).
• The global contribution from buildings towards energy consumption, both residential and commercial, has steadily increased reaching figures between 20 and 40% in developed countries, and has exceeded the other major sectors: industrial and transportation.
• This paper analyses available information concerning energy consumption in buildings, and particularly related to HVAC systems.
• Comparisons between different countries are presented specially for commercial buildings.

1. World energy use

• The rapidly growing world energy use has already raised concerns over supply difficulties, exhaustion of energy resources and heavy environmental impacts (ozone layer depletion, global warming, climate change, etc).
• The International Energy Agency has gathered frightening data on energy consumption trends.
• Current predictions show that this growing trend will continue.
• These figures confirm the relationship linking energy consumption with economic development and population growth, and question global policy attempts to invert this trend by increasing energy efficiency (including renewable and green technologies).
• Current energy and socio-economic systems are definitively unsustainable.

2. Energy consumption in buildings

• Final energy consumption is usually shown split into three main sectors: industry, transport and ‘other’, including in the last-named, agriculture, service sector and residential.
• Energy consumption in buildings other than dwellings constitutes a fraction of the services shared within the ‘other’ key sector.
• In contrast building energy consumption in Spain is increasing at a rate of 4.2% per annum, well above both the European and the North American (1.9%) rate.
• In the UK, the proportion of energy use in building (39%) is slightly above the European figure.
• By and large, dwellings in developed countries use more energy than those in emerging economies and it is expected to continue growing due to the installation of new appliances (air conditioners, computers, etc).

3. Heating, ventilation and air conditioning (HVAC)

• The proliferation of energy consumption and CO2 emissions in the built environment has made energy efficiency and savings strategies a priority objective for energy policies in most countries.
• A clear example is the European Energy Performance of Buildings Directive (EPBD) [3].
• Its predominance is obvious when it is compared with other end uses.
• At the European level, the weight of HVAC is unknown; however, many sources show a significant increase in the use of air conditioning, especially in Southern countries (Spain and Italy accounts for more than 50% of the European market), creating serious supply difficulties during peak load periods.
• By and large, HVAC consumption in developed countries accounts for half the energy use in buildings and one fifth of the total national energy use.

4. Non-domestic buildings

• In non-domestic buildings, the type of use and activities make a huge impact on the quality and quantity of energy services needed.
• Few sources offer data by typology and there is not consensus on a universal classification, which makes the analysis extremely difficult.
• Across the rest of Europe energy consumption in the commercial sector grows at a higher rate than other sectors due predominantly to the expansion of HVAC systems in new buildings [10].
• Hotels and restaurants, hospitals and schools follow.
• Building type is critical in how energy end uses are distributed and in their energy intensity (Table 6).

5. Office Buildings

• Within the commercial sector, office buildings are, together with retail, those with the biggest consumption and CO2 emissions.
• In USA offices account for 17% of total non domestic area and about 18% of the energy use, equivalent to a 3.2% of the total consumption.
• Other reasons, supporting energy surveys for this typology are: (1) The substantial increase of total built area of office buildings due to the economical prosperity with many new business developments in mayor city outskirts [11].
• Mm² were built in Spain, with no reliable information on the total built area.
• In Spain, more than 90% of companies use IT equipment and virtually all new offices are conditioned.

6. Conclusions

• Available information is clearly insufficient and not proportional to its importance.
• In that respect, studies developed by the EIA on the energy consumption of residential and commercial buildings in the USA are a valuable reference.
• Proliferation of energy consumption and CO2 emissions on the built environment have made energy efficiency strategies a priority for energy policies developing new building regulations and certification schemes which now include minimum requirements.
• With the consolidation of the demand for thermal comfort, HVAC systems (and its associated energy consumption) have become an unavoidable asset, accounting for almost half the energy consumed in buildings, and around 10 to 20% of total energy consumption in developed countries.

Figures

Table 1. Global energy indexes evolution between 1973 and 2004. Source: International Energy Agency (IEA).

Table 7. Energy consumption in offices by end use. Sources: EIA, BRE [12] and IDAE.

Table 4. Energy consumption by end uses in the residential sector. Year 2003. Source: EIA and IDAE [8] and BRE.

Table 5. Energy use in the commercial sector by building type. Year 2003. Sources: EIA, IDAE and BRE.

Table 3. Weight of buildings energy consumption. Year 2004. Sources: EIA, EuroStat, and BRE.

Table 6. Average energy use intensity by building type in USA. Year 2003. Source: EIA.

Table 2. World final energy consumption by sector. Source: IEA.

Frequently asked questions

Q1. What are the contributions mentioned in the paper "A review on buildings energy consumption information" ?

This paper analyses available information concerning energy consumption in buildings, and particularly related to HVAC systems. 

Q2. What future works have the authors mentioned in the paper "A review on buildings energy consumption information" ?

It is essential to make available comprehensive building energy information to allow suitable analysis and efficiently plan energy policies for the future. The growing trend in building energy consumption will continue during the coming years due to the expansion of built area and associated energy needs, as long as resource and environmental exhaustion or economic recession allows it. Private initiative together with government intervention through the promotion of energy efficiency, new technologies for energy production, limiting energy consumption and raising social awareness on the rational use of energy will be essential to make possible a sustainable energy future. 

Q3. What is the energy intensive typology?

(2) Office and retail are the most energy intensive typologies typically accounting for over 50% of the total energy consumption for non-domestic buildings. 

Q4. What is the average energy consumption in the US?

In USA offices account for 17% of total non domestic area and about 18% of the energy use, equivalent to a 3.2% of the total consumption. 

Q5. What is the average energy consumption of buildings in the USA?

With the consolidation of the demand for thermal comfort, HVAC systems (and its associated energy consumption) have become an unavoidable asset, accounting for almost half the energy consumed in buildings, and around 10 to 20% of total energy consumption in developed countries. 

Q6. What are the main reasons for the increase in energy consumption in the built environment?

Proliferation of energy consumption and CO2 emissions on the built environment have made energy efficiency strategies a priority for energy policies developing new building regulations and certification schemes which now include minimum requirements. 

Q7. What are the main factors for energy consumption in dwellings?

The amount and type of energy used in dwellings are mainly related to weather, architectural design, energy systems and economic level of the occupants. 

Q8. What is the importance of the analysis by sectors?

Analysis by sectors, as those produced by the EIA for residential [6] and commercial buildings [7] should be funded by governments, so that a comprehensive database of the building stock (type, area, location, age…) and energy parameters (consumption, expenditures, fuels, end uses…) can be the basis for future planning. 

Q9. How much energy is used in buildings?

By and large, HVAC consumption in developed countries accounts for half the energy use in buildings and one fifth of the total national energy use. 

Q10. What are the main reasons for the rapid growth of the world energy use?

The rapidly growing world energy use has already raised concerns over supply difficulties, exhaustion of energy resources and heavy environmental impacts (ozone layer depletion, global warming, climate change, etc). 

Q11. What is the main reason for the increase in energy consumption in the commercial sector?

Across the rest of Europe energy consumption in the commercial sector grows at a higher rate than other sectors due predominantly to the expansion of HVAC systems in new buildings [10]. 

Q12. What is the main reason for the proliferation of energy consumption and CO2 emissions in the built environment?

The proliferation of energy consumption and CO2 emissions in the built environment has made energy efficiency and savings strategies a priority objective for energy policies in most countries. 

Q13. What is the main reason for the increase in energy consumption in the built environment?

By and large, dwellings in developed countries use more energy than those in emerging economies and it is expected to continue growing due to the installation of newappliances (air conditioners, computers, etc). 

Q14. What is the impact of HVAC on the quality of the energy services needed?

In non-domestic buildings, the type of use and activities make a huge impact on the quality and quantity of energy services needed. 

Q15. What is the average growth rate of energy consumption in the service sector in non-developed countries?

It is expected that energy consumption in the service sector in non-developed countries will be doubled in the next 25 years, with an annual average growth rate of 2.8%. 

Q16. What is the average growth rate of energy use by emerging economies?

Energy use by nations with emerging economies (Southeast Asia, Middle East, South America and Africa) will grow at an average annual rate of 3.2% and will exceed by 2020 that for the developed countries (North America, Western Europe, Japan, Australia and New Zealand) at an average growing rate of 1.1% (Figure 2). 

Q17. Why is the office building a good choice for energy surveys?

Other reasons, supporting energy surveys for this typology are:(1) The substantial increase of total built area of office buildings due to the economical prosperity with many new business developments in mayor city outskirts [11]. 

Q18. What is the average increase in primary energy?

During the last two decades (1984-2004) primary energy has grown by 49% and CO2 emissions by 43%, with an average annual increase of 2% and 1.8% respectively (Figure 1). 

Q19. What is the importance of building energy consumption in the UK?

Looking to the evolution (Figure 3) and importance (Table 3) of building energy consumption, the authors conclude:(1) In the UK building energy consumption has increased at a rate of 0.5% per annum, which is slightly below the European figure of 1.5%.