Energy Efficiency
A
Aerothermal energy is the energy stored in the form of heat in the ambient air.

Air-conditioning system

is a combination of all components required to provide a form of air treatment in which temperature is
controlled or can be lowered, possibly in combination with the control of ventilation, humidity and air cleanliness.

B
Biofuels

are liquid or gaseous fuel for transport produced from biomass [18] [19].

Bioliquids are liquid fuel for energy purposes other than for transport, including electricity and heating and cooling, produced from biomass [18].
Directive 2009/28/EC of the European Parliament and of the Council of 23 April 2009 ,on the promotion of the use of energy from renewable sources and amending ans subsequently repealing directives 2001/77/EC and 2003/30/EC (Text with EEA relevance) Official Journal of European Union, 05.06.2009.
Biomass is the biodegradable fraction of products, waste and residues from biological origin from agriculture (including vegetal and animal substances), forestry and related industries including fisheries and aquaculture, as well as the biodegradable fraction of industrial and municipal waste [18] [19].
Directive 2003/30/EC of The European Parliament and of The Council of 8 May 2003 on the promotion of the use of biofuels or other renewable fuels for transport
Directive 2009/28/EC of the European Parliament and of the Council of 23 April 2009 ,on the promotion of the use of energy from renewable sources and amending ans subsequently repealing directives 2001/77/EC and 2003/30/EC (Text with EEA relevance) Official Journal of European Union, 05.06.2009.
Boiler is the combined boiler body and burner-unit designed to transmit to water the heat released from combustion [15], [16].
Directive 2002/91/EC of the European Parliament and of the Council of 16 December 2002 on the energy performance of buildings, Official Journal of European Union, 04.01.2003.
Directive 2010/31/EU of the European Parliament and of the Council of 16 May 2010 on the energy performance of buildings (recast), Official Journal of European Union, 18.06.2010.
Building automation system (BAS) is a system that provides efficient and effective control of complete building system which monitors by means of computerized tools in order to control energy performance and possible failures within the system. These systems can be applied to different components of the residential, commercial, industrial and office buildings’ systems e.g. electricity, HVAC, lightning, etc. Their general interest is to improve the interaction among integrated systems and occupants [20], [21].
João F. and M. (2010), Energy Production System Management – Renewable energy power supply integration with Building Automation System, Energy Conversion and Management Volume 51, Issue 6, pp. 1120–1126.
Building energy management systems (BEMS)

an be described as the systems provide the necessary thermal comfort and indoor air
quality with satisfied energy needs by means of centralized controlling, monitoring and reporting mechanisms. These systems can be also
thought as instruments that allow controlling active systems of buildings, their operating times and management of the building. The main
purpose of these systems is to provide satisfied necessary energy needs with minimum energy consumption and environmental impact
[22], [23] Figure 7.

C
Carbon dioxide emissions measured in kilograms of CO2 per square meter (kgCO2/m2/year) annual use of energy in specific terms, such as the number of kilowatt hours used per square meter (kWh/m2/year).
Carbon dioxide equivalent (CO2eqv) computing the amount of CO2 that would have the same effects as other greenhouse gas emissions, such as methane [24].
Carbon footprint

is emissions associated with the use of power, transport, food and other consumption for an individual, family or organization are added up to give one comparable measure in units of carbon dioxide equivalent [24].

The impact of human activities in terms of the amount of greenhouse gases they produce [25].

Cogeneration

is simultaneous generation in one process of thermal energy and electrical and/or mechanical energy [16] [ 26].

Combined heat and power is the simultaneous conversion of primary fuels into mechanical or electrical and thermal energy, meeting certain quality criteria of energy efficiency [15].
Directive 2002/91/EC of the European Parliament and of the Council of 16 December 2002 on the energy performance of buildings, Official Journal of European Union, 04.01.2003.
Cost benefit analysis

Financial tool which allows a decision maker to consider a number of complicated environmental, social and economic factors to permit a cost optimum choice to be made [25].

Cost-optimal level is the energy performance level which leads to the lowest cost during the estimated economic lifecycle, where: (a) the lowest cost is determined taking into account energy-related investment costs, maintenance and operating costs (including energy costs and savings, the category of building concerned, earnings from energy produced), where applicable, and disposal costs, where applicable; and (b) the estimated economic lifecycle is determined by each Member State. It refers to the remaining estimated economic lifecycle of a building where energy performance requirements are set for the building as a whole, or to the estimated economic lifecycle of a building element where energy performance requirements are set for building elements [24].
ASTM E2725-10. (2010) Basic Assessment and Management of Greenhouse Gases
D
Distribution system operator

means a natural or legal person, including a distribution system operator, responsible for transporting energy with a view to its delivery to final customers or to distribution stations that sell energy to final customers [1], [28].

Directive 2006/32/Ec of The European Parliament and of the Council of 5 April 2006 on energy end-use efficiency and energy services and repealing Council Directive 93/76/EEC (Text with EEA relevance), Official Journal of the European Union, 27.4.2006.
Directive 2012/27/EU of the European Parliament and of the Council of 25 October 2012 ,on energy efficiency and amending directives 2009/125/EC and 2010/30/EU and repealing directives 2004/8/EC and 2006/30/EC (Text with EEA relevance) Official Journal of European Union, 14.11.2009.
District heating/district cooling is the distribution of thermal energy in the form of steam, hot water or chilled liquids, from a central source of production through a network to multiple buildings or sites, for the use of space or process heating or cooling [18].
Directive 2009/28/EC of the European Parliament and of the Council of 23 April 2009 ,on the promotion of the use of energy from renewable sources and amending ans subsequently repealing directives 2001/77/EC and 2003/30/EC (Text with EEA relevance) Official Journal of European Union, 05.06.2009.
E
Effective rated output (expressed in kW) is the maximum calorific output specified and guaranteed by the manufacturer as being deliverable during continuous operation while complying with the useful efficiency indicated by the manufacturer [15], [16].
Directive 2002/91/EC of the European Parliament and of the Council of 16 December 2002 on the energy performance of buildings, Official Journal of European Union, 04.01.2003.
Directive 2010/31/EU of the European Parliament and of the Council of 16 May 2010 on the energy performance of buildings (recast), Official Journal of European Union, 18.06.2010.
Efficient district heating and cooling cooling’ means a district heating or cooling system using at least 50 % renewable energy, 50 % waste heat, 75 % cogenerated heat or 50 % of a combination of such energy and heat [28].
Directive 2012/27/EU of the European Parliament and of the Council of 25 October 2012 ,on energy efficiency and amending directives 2009/125/EC and 2010/30/EU and repealing directives 2004/8/EC and 2006/30/EC (Text with EEA relevance) Official Journal of European Union, 14.11.2009.
Efficient heating and cooling means a heating and cooling option that, compared to a baseline scenario reflecting a business-as-usual situation, measurably reduces the input of primary energy needed to supply one unit of delivered energy within a relevant system boundary in a cost-effective way, as assessed in the cost-benefit analysis referred to in this Directive, taking into account the energy required for extraction, conversion, transport and distribution [28].
Directive 2012/27/EU of the European Parliament and of the Council of 25 October 2012 ,on energy efficiency and amending directives 2009/125/EC and 2010/30/EU and repealing directives 2004/8/EC and 2006/30/EC (Text with EEA relevance) Official Journal of European Union, 14.11.2009.
Efficient individual heating and cooling means an individual heating and cooling supply option that, compared to efficient district heating and cooling, measurably reduces the input of non-renewable primary energy needed to supply one unit of delivered energy within a relevant system boundary or requires the same input of non-renewable primary energy but at a lower cost, taking into account the energy required for extraction, conversion, transport and distribution [28].
Directive 2012/27/EU of the European Parliament and of the Council of 25 October 2012 ,on energy efficiency and amending directives 2009/125/EC and 2010/30/EU and repealing directives 2004/8/EC and 2006/30/EC (Text with EEA relevance) Official Journal of European Union, 14.11.2009.
Embodied Energy is defined as the energy used during the entire life cycle of a product including the energy used for manufacturing, transporting, and disposing of the product. Embodied energy, as related to life cycle assessment (LCA), is a useful tool for evaluating the relative environmental impact of various building materials because it takes production, transportation and disposal into account, all things that can have a pronounced environmental impact but are not necessarily reflected in the price. Due to the complexity of calculations and the wide range of production methods, transportation distances and other variables for some building products, exact figures for embodied energy vary from study to study. Fortunately, precise figures are not necessary. Builders, designers, purchasers and others can make informed decisions based on the embodied energy of a given product relative to its substitutes. It should be noted that when considering the embodied energy of an entire building, the energy embodied in the building materials is small relative to the energy it takes to operate that building over its lifetime. Looking at the embodied energy of a typical building, for example, only 15% of that energy is embodied in the materials used to make the building; the other 85% is in the operation of the building over its lifetime [29], [30]. Another definition by ASTM E2114 [27] is the energy used through the life cycle of a material or product to extract, refine, process, fabricate, transport, install, commission, utilize, maintain, remove, and ultimately recycle or dispose of the substances comprising the item.
B. Lippke et. Al. (2004), Life-Cycle Environmental Performance of Renewable Building Materials, Journal of Forest Products, vol.54, pp 8-19.
Energy all forms of commercially available energy, including electricity, natural gas (including liquefied natural gas), liquefied petroleum gas, any fuel for heating and cooling (including district heating and cooling), coal and lignite, peat, transport fuels (excluding aviation and maritime bunker fuels) and biomass as defined in Directive 2001/77/EC of the European Parliament and of the Council of 27 September 2001 on the promotion of electricity produced from renewable energy sources in the internal electricity market [1].
Directive 2006/32/Ec of The European Parliament and of the Council of 5 April 2006 on energy end-use efficiency and energy services and repealing Council Directive 93/76/EEC (Text with EEA relevance), Official Journal of the European Union, 27.4.2006.
Energy audit means a systematic procedure with the purpose of obtaining adequate knowledge of the existing energy consumption profile of a building or group of buildings, an industrial or commercial operation or installation or a private or public service, identifying and quantifying cost-effective energy savings opportunities, and reporting the findings [28].
Directive 2012/27/EU of the European Parliament and of the Council of 25 October 2012 ,on energy efficiency and amending directives 2009/125/EC and 2010/30/EU and repealing directives 2004/8/EC and 2006/30/EC (Text with EEA relevance) Official Journal of European Union, 14.11.2009.
Energy Certification of Buildings is a representation of an achievement in energy efficiency process that involves planning, applying, controlling and verifying of energy efficiency improvement, energy consumption reduction and enabling transparency in terms of energy usage in buildings. These buildings combine high health, comfort and environmental quality and performance, also high technical quality and long-term perspective building functions in economic way. BREEAM, LEED, DGNB and HQE are some examples for energy certification systems [112] [113].
Assessment methodologies usually use software tools to calculate energy performance and ratings. Most of the time this will be based on the annual use of energy in specific terms, such as the number of kilowatt hours user per square meter (kWh/m2/year. They can also measure CO2 emissions, measured in kilograms of CO2 per square meter (kgCO2/m2/year) [114].
The calculation methodologies and the relevant software should be considered as efficient whether;
they are suitable to existing national and international standards,
- easily adaptable to changes in these standards, their outputs clearly reflect the actual energy use in both asset and operational ratings, outputs allow comparison with similar buildings located in similar environments, it is possible to validate the calculation methods of the software,
- the software is user-friendly [115].
Some examples of free-software are: EnergyPlus, ESP-r, SBEM, etc. Pérez-Lombarda, L., Ortizb, J., Gonzáleza, R., Maestrec, I.R. (2009), A review of benchmarking, rating and labelling concepts within the framework of building energy certification schemes, Energy and Buildings Volume 41, Issue 3, Pages 272–278). International Energy Agency. (2010) Energy performance certification of buildings. Paris: OECD/IEA.
Pérez-Lombarda, L., Ortizb, J., Gonzáleza, R., Maestrec, I.R. (2009), A review of benchmarking, rating and labelling concepts within the framework of building energy certification schemes, Energy and Buildings Volume 41, Issue 3, Pages 272–278).
International Energy Agency. (2010) Energy performance certification of buildings. Paris: OECD/IEA.
Energy conservation means performing less work, using less light, heat, and movement [47].
Energy consumption in buildings

heating and cooling are the main energy consumers in buildings and account for approximately 35%-40% of a building’s total energy consumption. However in some buildings, most of this energy is wasted due to inadequate insulation. In most cases well-proven energy efficiency techniques, can be cut 70 to 90% of a building’s energy need for heating or cooling [12].

Energy distributor

means a natural or legal person, including a distribution system operator, responsible for transporting energy with a view to its delivery to final customers or to distribution stations that sell energy to final customers [1], [28].

Directive 2006/32/Ec of The European Parliament and of the Council of 5 April 2006 on energy end-use efficiency and energy services and repealing Council Directive 93/76/EEC (Text with EEA relevance), Official Journal of the European Union, 27.4.2006.
Directive 2012/27/EU of the European Parliament and of the Council of 25 October 2012 ,on energy efficiency and amending directives 2009/125/EC and 2010/30/EU and repealing directives 2004/8/EC and 2006/30/EC (Text with EEA relevance) Official Journal of European Union, 14.11.2009.
Energy efficiency means the ratio of output of performance, service, goods or energy, to input of energy [28]. Energy efficiency is also defined as reducing energy consumption without causing any diminution in living standards and service quality in buildings as well as in the product quality and amount in the industrial sector [2], [4].
Yildiz, Y. (2008), Retrofitting Existing Mass Housing For Energy Efficiency: A Case Study In Gaziemir Emlak Bank Housing Area, Izmir, Turkey. Thesis Submitted to the Graduate School of Engineering and Science of IYTE, MsC Thesis in Architecture, Izmir.
Ministry of Energy and Natural Resources (MENR) (2007). Energy Efficiency Law, RG [Official Gazette, Number: 5627]. (in Turkish).
Directive 2012/27/EU of the European Parliament and of the Council of 25 October 2012 ,on energy efficiency and amending directives 2009/125/EC and 2010/30/EU and repealing directives 2004/8/EC and 2006/30/EC (Text with EEA relevance) Official Journal of European Union, 14.11.2009.
Energy efficiency improvement means an increase in energy efficiency as a result of technological, behavioural and/or economic changes [28].
Directive 2012/27/EU of the European Parliament and of the Council of 25 October 2012 ,on energy efficiency and amending directives 2009/125/EC and 2010/30/EU and repealing directives 2004/8/EC and 2006/30/EC (Text with EEA relevance) Official Journal of European Union, 14.11.2009.
Energy efficiency improvement measures are all actions that normally lead to verifiable and measurable or estimable energy efficiency improvement means a natural or legal person, including a distribution system operator, responsible for transporting energy with a view to its delivery to final customers or to distribution stations that sell energy to final customers [1],
Directive 2006/32/Ec of The European Parliament and of the Council of 5 April 2006 on energy end-use efficiency and energy services and repealing Council Directive 93/76/EEC (Text with EEA relevance), Official Journal of the European Union, 27.4.2006.
Energy efficiency improvement programmes means a natural or legal person, including a distribution system operator, responsible for transporting energy with a view to its delivery to final customers or to distribution stations that sell energy to final customers [1], [28].
Directive 2006/32/Ec of The European Parliament and of the Council of 5 April 2006 on energy end-use efficiency and energy services and repealing Council Directive 93/76/EEC (Text with EEA relevance), Official Journal of the European Union, 27.4.2006.
Directive 2012/27/EU of the European Parliament and of the Council of 25 October 2012 ,on energy efficiency and amending directives 2009/125/EC and 2010/30/EU and repealing directives 2004/8/EC and 2006/30/EC (Text with EEA relevance) Official Journal of European Union, 14.11.2009.
Energy efficiency mechanisms are general instruments used by governments or government bodies to create a supportive framework or incentives for market actors to provide and purchase energy services and other energy efficiency improvement measures [1].
Directive 2006/32/Ec of The European Parliament and of the Council of 5 April 2006 on energy end-use efficiency and energy services and repealing Council Directive 93/76/EEC (Text with EEA relevance), Official Journal of the European Union, 27.4.2006.
Energy from renewable sources are the energy from renewable non-fossil sources, namely wind, solar, aeothermal, geothermal, hydrothermal and ocean energy, hydropower, biomass, landfill gas, sewage treatment plant gas and biogases [16], [18].
Directive 2010/31/EU of the European Parliament and of the Council of 16 May 2010 on the energy performance of buildings (recast), Official Journal of European Union, 18.06.2010.
Directive 2009/28/EC of the European Parliament and of the Council of 23 April 2009 ,on the promotion of the use of energy from renewable sources and amending ans subsequently repealing directives 2001/77/EC and 2003/30/EC (Text with EEA relevance) Official Journal of European Union, 05.06.2009.
Energy intensity is the amount of primary energy consumed per gross national income [31]. “At the national level, energy intensity is the ratio of total domestic primary energy consumption or final energy consumption to gross domestic product or physical output”. If the energy intensity is less in a country, a product can be produced with less energy. It means that energy efficiency is achievable as well [4].
Haydaroglu, C. (2006). Türk sanayinde enerji verimliligi ve yogunlugu analizi. Anadolu University. Thesis of MS (in Turkish).
Yildiz, Y. (2008), Retrofitting Existing Mass Housing For Energy Efficiency: A Case Study In Gaziemir Emlak Bank Housing Area, Izmir, Turkey. Thesis Submitted to the Graduate School of Engineering and Science of IYTE, MsC Thesis in Architecture, Izmir.
Energy management system means a set of interrelated or interacting elements of a plan which sets an energy efficiency objective and a strategy to achieve that objective [28].
Directive 2012/27/EU of the European Parliament and of the Council of 25 October 2012 ,on energy efficiency and amending directives 2009/125/EC and 2010/30/EU and repealing directives 2004/8/EC and 2006/30/EC (Text with EEA relevance) Official Journal of European Union, 14.11.2009.
Energy performance contracting means a contractual arrangement between the beneficiary and the provider of an energy efficiency improvement measure, verified and monitored during the whole term of the contract, where investments (work, supply or service) in that measure are paid for in relation to a contractually agreed level of energy efficiency improvement or other agreed energy performance criterion, such as financial savings [28].
Directive 2012/27/EU of the European Parliament and of the Council of 25 October 2012 ,on energy efficiency and amending directives 2009/125/EC and 2010/30/EU and repealing directives 2004/8/EC and 2006/30/EC (Text with EEA relevance) Official Journal of European Union, 14.11.2009.
Energy savings means an amount of saved energy determined by measuring and/or estimating consumption before and after implementation of an energy efficiency improvement measure, whilst ensuring normalisation for external conditions that affect energy consumption [28].
Directive 2012/27/EU of the European Parliament and of the Council of 25 October 2012 ,on energy efficiency and amending directives 2009/125/EC and 2010/30/EU and repealing directives 2004/8/EC and 2006/30/EC (Text with EEA relevance) Official Journal of European Union, 14.11.2009.
Energy service means the physical benefit, utility or good derived from a combination of energy with energy-efficient technology or with action, which may include the operations, maintenance and control necessary to deliver the service, which is delivered on the basis of a contract and in normal circumstances has proven to result in verifiable and measurable or estimable energy efficiency improvement or primary energy savings [28].
Directive 2012/27/EU of the European Parliament and of the Council of 25 October 2012 ,on energy efficiency and amending directives 2009/125/EC and 2010/30/EU and repealing directives 2004/8/EC and 2006/30/EC (Text with EEA relevance) Official Journal of European Union, 14.11.2009.
Energy service company (ESCO) is a natural or legal person that delivers energy services and/or other energy efficiency improvement measures in a user's facility or premises, and accepts some degree of financial risk in so doing. The payment for the services delivered is based (either wholly or in part) on the achievement of energy efficiency improvements and on the meeting of the other agreed performance criteria [1].
Directive 2006/32/Ec of The European Parliament and of the Council of 5 April 2006 on energy end-use efficiency and energy services and repealing Council Directive 93/76/EEC (Text with EEA relevance), Official Journal of the European Union, 27.4.2006.
Energy service provider means a natural or legal person who delivers energy services or other energy efficiency improvement measures in a final customer’s facility or premises [28].
Directive 2012/27/EU of the European Parliament and of the Council of 25 October 2012 ,on energy efficiency and amending directives 2009/125/EC and 2010/30/EU and repealing directives 2004/8/EC and 2006/30/EC (Text with EEA relevance) Official Journal of European Union, 14.11.2009.
Environmental certification of buildings is a representation of an achievement in energy efficiency process that involves planning, applying, controlling and verifying of energy efficiency improvement, energy consumption reduction and enabling transparency in terms of energy usage in buildings.

These buildings combine high health, comfort and environmental quality and performance, also high technical quality and long-term perspective building functions in economic way. BREEAM, LEED, DGNB and HQE are some examples for energy certification systems [112] [113].

Assessment methodologies usually use software tools to calculate energy performance and ratings. Most of the time this will be based on the annual use of energy in specific terms, such as the number of kilowatt hours user per square meter (kWh/m2/year. They can also measure CO2 emissions, measured in kilograms of CO2 per square meter (kgCO2/m2/year) [114].

The calculation methodologies and the relevant software should be considered as efficient whether;

  • they are suitable to existing national and international standards, - easily adaptable to changes in these standards,
  • their outputs clearly reflect the actual energy use in both asset and operational ratings,
  • outputs allow comparison with similar buildings located in similar environments,
  • it is possible to validate the calculation methods of the software, - the software is user-friendly [115].


Some examples of free-software are: EnergyPlus, ESP-r, SBEM, etc.

Pérez-Lombarda, L., Ortizb, J., Gonzáleza, R., Maestrec, I.R. (2009), A review of benchmarking, rating and labelling concepts within the framework of building energy certification schemes, Energy and Buildings Volume 41, Issue 3, Pages 272–278).
International Energy Agency. (2010) Energy performance certification of buildings. Paris: OECD/IEA.
F
Final customer means a natural or legal person who purchases energy for own end use [28].
Directive 2012/27/EU of the European Parliament and of the Council of 25 October 2012 ,on energy efficiency and amending directives 2009/125/EC and 2010/30/EU and repealing directives 2004/8/EC and 2006/30/EC (Text with EEA relevance) Official Journal of European Union, 14.11.2009.
Final energy consumption means all energy supplied to industry, transport, households, services and agriculture. It excludes deliveries to the energy transformation sector and the energy industries themselves [28].
Directive 2012/27/EU of the European Parliament and of the Council of 25 October 2012 ,on energy efficiency and amending directives 2009/125/EC and 2010/30/EU and repealing directives 2004/8/EC and 2006/30/EC (Text with EEA relevance) Official Journal of European Union, 14.11.2009.
Financial instruments for energy savings are all financial instruments such as funds, subsidies, tax rebates, loans, third-party financing, energy performance contracting, guarantee of energy savings contracts, energy outsourcing and other related contracts that are made available to the market place by public or private bodies in order to cover partly or totally the initial project cost for implementing energy efficiency improvement measures [1].
Directive 2006/32/Ec of The European Parliament and of the Council of 5 April 2006 on energy end-use efficiency and energy services and repealing Council Directive 93/76/EEC (Text with EEA relevance), Official Journal of the European Union, 27.4.2006.
G
Geothermal energy is the energy stored in the form of heat beneath the surface of solid earth [18].
Directive 2009/28/EC of the European Parliament and of the Council of 23 April 2009 ,on the promotion of the use of energy from renewable sources and amending ans subsequently repealing directives 2001/77/EC and 2003/30/EC (Text with EEA relevance) Official Journal of European Union, 05.06.2009.
Greenhouse gases (GHGs) are vaporous constituents of the Earth’s atmosphere, both natural and anthropogenic, that absorb and emit radiation at speci?c wavelengths, including carbon dioxide, methane, nitrous oxide, hydro?uorocarbons, per?uorocarbons, and sulfur hexa?uoride [24].
ASTM E2725-10. (2010) Basic Assessment and Management of Greenhouse Gases
Greenhouse gas source is a physical unit or process that releases a GHG into the atmosphere [24].
ASTM E2725-10. (2010) Basic Assessment and Management of Greenhouse Gases
Green wall

Green walls or living walls are self sufficient vertical gardens that are attached to the exterior or interior of a building. They differ from green façades (e.g. ivy walls) in that the plants root in a structural support which is fastened to the wall itself. The plants receive water and nutrients from within the vertical support instead of from the ground [32].

H
Heat cost allocators are the devices that enable to measure total heat consumption by measuring the consumption of each individual radiator.
Heat pump is a machine, a device or installation that transfers heat from natural surroundings such as air, water or ground to buildings or industrial applications by reversing the natural flow of heat such that it flows from a lower to a higher temperature. For reversible heat pumps, it may also move heat from the building to the natural surroundings [16].
Directive 2010/31/EU of the European Parliament and of the Council of 16 May 2010 on the energy performance of buildings (recast), Official Journal of European Union, 18.06.2010.
Hybrid solar lighting is a novel approach to lighting systems whose working mechanism is based on collecting solar radiation separately as visible and as thermal (infrared-IR) portions. The former is used in lighting operations and the latter one is used in the production of electricity by means of thermal photovoltaics [33].
Schlegela, G.O., Burkholdera, F.W., Kleina, S.A., Beckmana, W.A., Woodb, B.D., Mu J.D. (2004), Analysis of a full spectrum hybrid lighting system Solar Energy Volume 76, Issue 4, pp. 359–368.
Hydrothermal energy is the energy stored in the form of heat in surface water [18].
Directive 2009/28/EC of the European Parliament and of the Council of 23 April 2009 ,on the promotion of the use of energy from renewable sources and amending ans subsequently repealing directives 2001/77/EC and 2003/30/EC (Text with EEA relevance) Official Journal of European Union, 05.06.2009.
I
Insulation is the sum of the processes (techniques) that are applied on buildings’ components in order prevent these components from unwanted effects of nature i.e. unwanted heat (losses & gains), moisture, noise, etc. to provide a comfortable medium for occupants, to provide energy efficiency and to achieve economic benefits during the structures’ service life.
Intelligent lighting system

system is the systems developed by using available lighting guidelines, techniques and equipment in most energy efficient way. Intelligent (smart) indoor & outdoor lighting system is applied to obtain light in highest quality and in most appropriate illumination level and to control light trespass [34].

J
K
L
LED

stands for light-emitting diode. LEDs are small light sources that become illuminated by the movement of electrons through a semiconductor material. LEDs can be integrated into all sorts of products to provide white and colored light, such as flashlights, light bulbs, and integrated light fixtures [35].

Life-cycle is consecutive and interlinked stages of a product system, from raw material acquisition or generation from natural resources to ?nal disposal in environmental impact management [36].
ISO 14040 (2006). Environmental Management Life Cycle Assessment Principles and Framework - Second Edition
Life cycle analysis (assessment) LCA

LCA is a technique for assessing the potential environmental aspects and potential aspects associated with a product (or service), by:

  • compiling an inventory of relevant inputs and outputs,
  • evaluating the potential environmental impacts associated with those inputs and outputs,
  • interpreting the results of the inventory and impact phases in relation to the objectives of the study [37].
Life-cycle cost (LCC) method

method is a technique of economic evaluation that sums over a given study period the costs of initial investment (less resale value), replacements, operations (including energy use), and maintenance and repair of an investment decision (expressed in present or annual value terms) [31].

DISCUSSION—LCC method is distinct from LCA in that LCA is an environmental review methodology and LCC method is an economic review methodology.

Liquid propane gas is a liquefied fossil fuel having less pollutant properties in addition to its tax concession which provides economical benefits in Europe [38], [40].
Jemni, M.A., Kantchev, G., Abid, M.A. (2011), Influence of intake manifold design on in-cylinder flow and engine performances in a bus diesel engine converted to LPG gas fuelled, using CFD analyses and experimental investigations, Energy 36, pp. 2701-2715.
M
Microcogeneration

is the simultaneous generation, within a small sized production unit, of heat and power by individual buildings, small businesses and communities to meet their own energy and heating needs [25].

N
O
Overall efficiency means the annual sum of electricity and mechanical energy production and useful heat output divided by the fuel input used for heat produced in a cogeneration process and gross electricity and mechanical energy production [28].
Directive 2012/27/EU of the European Parliament and of the Council of 25 October 2012 ,on energy efficiency and amending directives 2009/125/EC and 2010/30/EU and repealing directives 2004/8/EC and 2006/30/EC (Text with EEA relevance) Official Journal of European Union, 14.11.2009.
P
Passive down draught evaporative cooling is an approach to controlling ambient temperature by driving water out of fine nozzles by means of compressed air. Since the water droplets are in few microns-diameter they evaporate easily by absorbing the thermal mass of the air, which is also the reason of ambient temperature. Thus the temperature would be controlled in this manner [41].
Lomas, K.J., Fiala, D., Cook, M.J., Cropper P.C. (2004), Building bioclimatic charts for non-domestic buildings and passive downdraught evaporative cooling, Building and Environment Volume 39, Issue 6, pp. 661–676.
Primary energy is the energy from renewable and non- renewable sources which has not undergone any conversion or transformation process [16].
Directive 2010/31/EU of the European Parliament and of the Council of 16 May 2010 on the energy performance of buildings (recast), Official Journal of European Union, 18.06.2010.
Primary energy consumption means gross inland consumption, excluding non-energy uses [28].
Directive 2012/27/EU of the European Parliament and of the Council of 25 October 2012 ,on energy efficiency and amending directives 2009/125/EC and 2010/30/EU and repealing directives 2004/8/EC and 2006/30/EC (Text with EEA relevance) Official Journal of European Union, 14.11.2009.
Public bodies means the State, regional or local authorities, bodies governed by public law, associations formed by one or several of such authorities or one or several of such bodies governed by public law [28].
Directive 2012/27/EU of the European Parliament and of the Council of 25 October 2012 ,on energy efficiency and amending directives 2009/125/EC and 2010/30/EU and repealing directives 2004/8/EC and 2006/30/EC (Text with EEA relevance) Official Journal of European Union, 14.11.2009.
Q
R
Retail energy sales company means a natural or legal person who sells energy to final customers [28].
Directive 2012/27/EU of the European Parliament and of the Council of 25 October 2012 ,on energy efficiency and amending directives 2009/125/EC and 2010/30/EU and repealing directives 2004/8/EC and 2006/30/EC (Text with EEA relevance) Official Journal of European Union, 14.11.2009.
S
Small and medium-sized enterprises (SMEs) are the enterprises as defined in Title I of the Annex to Commission Recommendation 2003/361/EC of 6 May 2003;
- The category of micro, small and medium-sized enterprises (SMEs) is made up of enterprises which employ fewer than 250 persons and which have an annual turnover not exceeding EUR 50 million, and/or an annual balance sheet total not exceeding EUR 43 million.
- Within the SME category, a small enterprise is defined as an enterprise which employs fewer than 50 persons and whose annual turnover and/or annual balance sheet total does not exceed EUR 10 million.
- Within the SME category, a microenterprise is defined as an enterprise which employs fewer than 10 persons and whose annual turnover and/or annual balance sheet total does not exceed EUR 2 million [15].
Smart metering system (Intelligent metering system) means an electronic system that can measure energy consumption, providing more information than a conventional meter, and can transmit and receive data using a form of electronic communication [28].
Directive 2012/27/EU of the European Parliament and of the Council of 25 October 2012 ,on energy efficiency and amending directives 2009/125/EC and 2010/30/EU and repealing directives 2004/8/EC and 2006/30/EC (Text with EEA relevance) Official Journal of European Union, 14.11.2009.
Solar thermal energy uses sun to heat water or air. There are also so called "high temperature" solar cells that produce electricity by steam turbines. The thermal solar cell is a very simple technique that consists of implementing the greenhouse effect in boxes exposed to the sun [39] [40].
ASTM E2114-08 (2008) Sustainability Relative to the Performance of the Buildings.
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Thermal bridge is important for heat loss. If thermal performance is improved in one area with the addition of insulation, while an adjacent area is not insulated, a local cold spot – known as a thermal bridge or cold bridge – is created [44].
Thermal Flow can be either transient or steady process. While in transient-state thermal flow is time dependent, in steady-state the flow proceeds until the thermally interconnected (either in physical connection-state or in range of irradiative influence) system reaches the equilibrium state. There are three main types of mechanisms which can be either act alone or in combinations:
• Conduction requires a direct molecular connection,
• Convection requires a fluid (liquid or gas) medium to transfer heat,
• Radiation requires a line of sight connection between the surfaces involved to transfer the energy by means of electromagnetic waves through gas or vacuum [45].
Thermal loss is an inter-medium/body transfer of thermal energy, causes a decrease in heat from hotter medium/body to colder medium/body. Thermal loss can occur either in one, two or three dimensions. In almost all situations, loss occurs in three dimensions but in order to facilitate the calculations/measurements it is assumed that occurs in one dimension.
Thermal mass is the ability of a material to absorb heat energy. It is equivalent to thermal capacitance or heat capacity, the ability of a body to store thermal energy. A lot of heat energy is required to change the temperature of high density materials like concrete, bricks and tiles.
They are therefore said to have high thermal mass. Lightweight materials such as timber have low thermal mass. Correct use of thermal mass moderate internal temperatures by averaging day/night (diurnal) extremes. This increases comfort and reduces energy costs. Poor use of thermal mass can exacerbate the worst extremes of the climate and can be a huge energy and comfort liability. It can radiate heat all night during a summer heat wave, or absorb all the heat you produce on a winter night.
To be effective, thermal mass must be integrated with sound passive design techniques. This means having appropriate areas of glazing facing appropriate directions with appropriate levels of shading, insulation and thermal mass [46].
Transmission system operator means a natural or legal person responsible for operating, ensuring the maintenance of and, if necessary, developing the transmission system in a given area and, where applicable, its interconnections with other systems, and for ensuring the long-term ability of the system to meet reasonable demands for the transmission of electricity [18].
Directive 2009/28/EC of the European Parliament and of the Council of 23 April 2009 ,on the promotion of the use of energy from renewable sources and amending ans subsequently repealing directives 2001/77/EC and 2003/30/EC (Text with EEA relevance) Official Journal of European Union, 05.06.2009.
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