Energy Use Intensities for Non-Residential Buildings

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Energy Use Intensities for Non-Residential Buildings Conference Paper · December 2017

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48. MEÐUNARODNI KONGRES I IZLOŽBA O KLIMATIZACIJI GREJANJU I HLAÐENJU Beograd, Sava centar 6–8. XII 2017.

48th INTERNATIONAL CONGRESS & EXHIBITION ON HEATING REFRIGERATION AND AIR-CONDITIONING Belgrade, Sava Center 6–8 XII 2017

ZBORNIK RADOVA PROCEEDINGS

ZBORNIK RADOVA 48. MEĐUNARODNI KONGRES O GREJANJU, HLAĐENJU I KLIMATIZACIJI

2017

ZBORNIK RADOVA

48. međunarodni kongres o grejanju, hlađenju i klimatizaciji (Beograd, 6–8.12.2017) IZDAVAČ

Savez mašinskih i elektrotehničkih inženjera i tehničara Srbije (SMEITS) – Društvo za grejanje, hlađenje i klimatizaciju (KGH) Srbije Kneza Miloša 7a/II,11000 Beograd 2017. god. UREDNIK

Prof. dr Branislav Todorović, dipl. inž. RECENZENTI

Branislav Todorović, Marija Todorović, Milovan Živković, Slobodan Pejković, Petar Vasiljević, Bojan Bogdanović TIRAŽ

450 primeraka ŠTAMPA

Paragon, Beograd ISBN

978-86-81505-85-4 CIP- Каталогизација у публикацији Народна библиотека Србије 697(082)(0.034.2) 628.8(082)(0.034.2) 621.56/.59(082)(0.034.2) 620.9(082)(0.034.2) МЕЂУНАРОДНИ конгрес о климатизацији, грејању и хлађењу (48 ; 2017 ; Београд) Zbornik radova [Elektronski izvor] = Proceedings / 48. međunarodni kongres i izložba o klimatizaciji, grejanju i hlađenju, Beograd, 6-8. XII 2017. = 48th International Congress & Exhibition on Heating, Refrigeration and Air-Conditioning, Belgrade, 6-8 XII 2017 ; [urednik Branislav Todorović]. - Beograd : Savez mašinskih i elektrotehničkih inženjera i tehničara Srbije (SMEITS), Društvo za grejanje, hlađenje i klimatizaciju (KGH) Srbije, 2017 (Beograd : Paragon). - 1 elektronski optički disk (CD-ROM) ; 12 cm Sistemski zahtevi: Nisu navedeni. - Nasl. sa naslovnog ekrana. - Radovi na srp. i engl. jeziku. - Tiraž 450. - Napomene i bibliografske reference uz radove. - Bibliografija uz većinu radova. ISBN 978-86-81505-85-4 a) Климатизација - Зборници; b) Расхладна техника - Зборници; c) Грејање - Зборници d) Енергетски извори - Зборници COBISS.SR-ID 253938700

PREDGOVOR 48. međunarodni kongres i izložba o grejanju, hlađenju i klimatizaciji Za prilaz zdravim, održivim i rezilijentnim zgradama, naseljima i gradovima nula emisije CO2 Beograd, 6–8. XII 2017. Ovogodišnji skup je planiran da bude u duhu tema koje danas obuhvataju aktuelne zadatke svetske energetike i očuvanja životnog prostora i da okupi sve profile učesnika u gradnji zgrada i njihovom energetskom opremanju: energetičare, arhitekte kao i građevince koji ujedinjenim naporima stvaraju objekte, posebno one koji u budućnosti treba da budu nula energije. Rukovodeći se naglašenim potrebama za saradnjom svih učesnika u projektovanju i građenju zgrada, u Organizacionom odboru su predstavnici više struka. Spisak tema je širok kako bi se podstakle sve institucije, obrazovne, projektantske, montažerske, kao i one administrativno-pravnog profila, da svojim nastupom, svaka u svojoj specijalnost, upotpune celokupnu problematiku energetike koja se odnosi na građevinske objekte. Predviđen je i poseban program za studente visokoškolskih i univerzitetskih institucija. Kongres i ove godine prati izložba uređaja, sistema, aparata, opreme, koji se ugrađuju i koriste u građevinskim objektima, kao i odgovarajućih instrumenata, materijala i softverskih programa, koji su u vezi sa energetskim potrebama stambenih, javnih i industrijskih zgrada. U Beogradu, novembra 2017.

UREDNIK

Sadržaj 1. ZELENI STANDARD ZA PROCENU FUDBALSKIH STADIONA ZA FIFA SVETSKI KUP 2018. GODINE

Iurii TABUNSHCHIKOV, Marianna BRODACH . . . . . . . . . . . . . . . . . . . . 11

2. EKSERGIJA KAO MERA ODRŽIVOSTI ENERGETSKOG SISTEMA

Peter NOVAK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

3. PRIMENA GEOTERMALNIH IZVORA ENERGIJE U FUNKCIJI ZAŠTITE ŽIVOTNE SREDINE

Miroslav VULIĆ, Kristijan VUJIČIN . . . . . . . . . . . . . . . . . . . . . . . . . . 41

4. DOPRINOS GEOTERMALNE ENERGIJE URBANOJ TRANSFORMACIJI GRADA UTIKE U SAD, SA ASPEKTA URBANISTIČKOG PLANIRANJA

Aleksandar JOVANOVIĆ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

51

5. SISTEMI ZA SEZONSKO SKLADIŠTENJE SOLARNE ENERGIJE U ZGRADAMA

Uroš STRITIH, Rok KOŽELJ, Urška MLAKAR . . . . . . . . . . . . . . . . . . . . . 61

6. PROVERA INTEGRITETA ANALITIČKIH REZULTATA ČVRSTIH BIOGORIVA

Predrag PETROVIĆ, Marija PETROVIĆ . . . . . . . . . . . . . . . . . . . . . . . . 73

7. KOMPRIMOVANI PRIRODNI GAS (CNG) – PROIZVODNJA,TRANSPORT I PRIMENA

Marin IVOŠEV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

8. POVEĆANJE ENERGETSKE EFIKASNOSTI U SKLADU SA EVROPSKOM DIREKTIVOM 2012/27/EU U CILJU SMANJENJA POTROŠNJE ENERGIJE KRAJNJEG KORISNIKA

Romanas SAVICKAS, LL. M. Lauryna SAVICKIENE . . . . . . . . . . . . . . . . . . 97

9. CFD MODELIRANJE PROTOKA FLUIDA U POJEDINAČNIM KANALIMA PLOČASTIH RAZMENJIVAČA TOPLOTE

Dragan MANDIĆ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .109

10 KOMBINOVANI ŠTEDNJAK KAO IZVOR TOPLOTE U SISTEMIMA ETAŽNOG ILI CENTRALNOG GREJANJA

Mile S. ŠILJAK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

11. S ISTEM AUTOMATSKE DOPUNE ZATVORENE EKSPANZIONE POSUDE KORIŠĆENJEM TRANSMITERA PRITISKA I SENZORA MAKSIMALNOG NIVOA VODE

Vojkan ZDRAVKOVIĆ, Miroljub TODOROVIĆ . . . . . . . . . . . . . . . . . . . . .125

12. E KSPERIMENTALNA I NUMERIČKA STUDIJA INDIREKTNOG SLOBODNOG HLAĐENJA U EGZOTERMIČKOJ ZGRADI

Yazid KACED, Stephane Le MASSON, David NORTERSHAUSER, Patick GLUANNEC . . . . . . . . . . . . . . . . . . 133

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13. K AKO ĆE TRŽIŠTE REAGOVATI NA PREDSTOJEĆE POSTEPENO SMANJIVANJE HFC-A NAKON AMANDMANA U KIGALIJU?

Alexander Cohr PACHAI, Asbjørn Leth VONSILD . . . . . . . . . . . . . . . . . . .147

14. P RIRODNI RASHLADNI FLUIDI ZA PRIMENU NA NIŽIM TEMPERATURAMA

Jan BOONE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

15. P REDNOSTI INTEGRACIJE TOPLOTNIH PUMPI I SISTEMA ZA HLAĐENJE HRANE U KOMERICJALNIM PRIMENAMA: PRIMER EFIKASNE REKUPERACIJE ENERGIJE ZA ZGRADE GOTOVO NULTE ENERGIJE

Sergio Maria CAPANELLI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

16. R ASHLADNI FLUIDI: TRAJNA REŠENJA, ILI DUGOTRAJNE OBAVEZE?

Risto CICONKOV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .175

17. E KOLOŠKA ALTERNATIVA ZA TOPLOTNU PUMPU VAZDUH-VODA

Graţiela Maria TÂRLEA, Mioara VINCERIUC, Ana TARLEA, Florin Temistocle IONESCU . . . . . . . . . . . . . . . . . . . . . . .195

18. R UMUNSKO ISTRAŽIVANJE O HLAĐENJU I KLIMATIZACIJI

Liviu DRUGHEAN, Alexandru ŞERBAN, Florea CHIRIAC, Anica ILIE, Rodica DUMITRESCU . . . . . . . . . . . . . . . . . . . . . . . . . . .201

19. TOPLOTNI KOMFOR U UNIVERZITETSKIM ZGRADAMA – RAZLIKE IZMEĐU IZMERENIH VREDNOSTI I SUBJEKTIVNOG OSEĆAJA KORISNIKA

Tamara BAJC, Maja TODOROVIĆ . . . . . . . . . . . . . . . . . . . . . . . . . . .217

20. P RAKTIČNA PRIMENA SORPCIONIH ROTORA U TEHNICI SUŠENJA VAZDUHA ZA OBJEKTE RAZLIČITE NAMENE

Aleksandar PJEVIĆ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .225

21. M OGUĆNOST PRIMENE PLAFONSKOG SISTEMA GREJANJA ZA ZAGREVANJE SPORTKIH DVORANA

Dragan CVETKOVIĆ, Aleksandar NEŠOVIĆ, Jasmina SKERLIĆ, Danijela NIKOLIĆ . . . . . . . . . . . . . . . . . . . . . . . . .237

22. P OBOLJŠANJE ENERGETSKE EFIKASNOSTI I SMANJENJE NIVOA BUKE VENTILATOR KONVEKTORA

Dragan KOMAROV, Nikola JOVANOVIĆ, Dušica DRAGOJLOVIĆ . . . . . . . . . .247

23. S IMULACIJA ENERGETSKIH KARAKTERISTIKA STAMBENE ZGRADE

Norbert HARMATHY, Zoltan MAGYAR . . . . . . . . . . . . . . . . . . . . . . . . .255

24. P OTROŠNЈA FINALNE ENERGIJE ZA GREJANЈE PASIVNE KUĆE (SLUČAJ KRAGUJEVAC)

Aleksandar NEŠOVIĆ, Nebojša LUKIĆ, Novak NIKOLIĆ . . . . . . . . . . . . . 271

8

25. O OPTIMALNOJ ORIJENTACIJI ZGRADE

Nenad MILORADOVIĆ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .281

26. E LEKTRONSKI SISTEM ZA VOĐENJE EVIDENCIJE I IZVEŠTAVANJE ZASNOVAN NA SERTIFIKACIJI PREDUZEĆA

Peter TOMLEIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .293

27. U ŠTEDA ENERGIJE U SRPSKOJ PORODIČNOJ KUĆI SA HORIZONTALNIM NADSTREŠNICAMA

Slobodan ĐORĐEVIĆ, Danijela NIKOLIĆ, Jasmina SKERLIĆ, Jasna RADULOVIĆ, Dragan CVETKOVIĆ . . . . . . . . . . . .305

28. V ERIFIKACIJA OSTVARENIH UŠTEDA U POTROŠNJI FINALNE ENERGIJE ZBOG PRIMENE MERA ZA UNAPREĐENJE ENERGETSKE EFIKASNOSTI U OSNOVNOJ ŠKOLI „OLGA PETROV“

Bojana OPAČIĆ, Slobodan RUŽIĆ . . . . . . . . . . . . . . . . . . . . . . . . . . .313

29. A NALIZA KORIŠĆENJA ENERGIJE ZGRADE SA STANOVIŠTA KORISNIKA: STUDIJA SLUČAJA JEDNE STAMBENE ZGRADE

Zhidan, ZHAO, Mahdi, HOUCHATI, Abdlmonem, BEITELMAL . . . . . . . . . . . .335

30. U POREDNA ANALIZA METODA DISTRIBUCIJE VAZDUHA U SISTEMIMA ZA KLIMATIZACIJU

Berec GABOR, Vladimir MUNĆAN, Aleksandar ANĐELKOVIĆ . . . . . . . . . . 349

31. I NTENZITET KORIŠĆENJA ENERGIJE ZA NESTAMBENE ZGRADE

Constantinos A. BALARAS, Elena G. DASCALAKI, Kalliopi G. DROUTSA, Meletia MICHA, Simon KONTOYIANNIDIS, Athanassios A. ARGIRIOU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369

31. G RAĐEVINSKA FIZIKA U PROTOTIPU VODENE KUĆE

Zoltan MAGYAR, Jenő KONTRA, Mátyás GUTAI, Norbert HARMATHY, János VÁRFALVI . . . . . . . . . . . . . . . . . . . . . . . . .391

33. D ANAS JE NEPRIHVATLJIVA ZGRADA BEZ URAĐENOG TEHNIČKOG PRIJEMA

Andres SEPULVEDA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 401

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INTENZITETI KORIŠĆENJA ENERGIJE ZA NESTAMBENE ZGRADE ENERGY USE INTENSITIES FOR NON-RESIDENTIAL BUILDINGS Constantinos A. BALARAS1,*, Elena G. DASCALAKI1, Kalliopi G. DROUTSA1, Meletia MICHA2, Simon KONTOYIANNIDIS1, Athanassios A. ARGIRIOU3 1 Institute for Environmental Research & Sustainable Development, NOA, Athens, Greece 2 Physicist, Athens, Greece 3 Department of Physics, University of Patras, Greece https://doi.org/10.24094/kghk.017.48.1.369

U Evropi postoji oko 6,2 milijardi m2 korisne površine u nestambenim zgradama koje troši 141.2 Mtoe, što iznosi 13.3% ukupne finalne potrošnje energije. Sektor nestambenih zgrada je složeniji i heterogeniji od sektora stambenih zgrada, te su zbog toga vrlo ograničene dostupne infromacije o fondu nestambenih zgrada, nedostaju konkretni podaci o površini zgrada, karakteristikama konstrukcije i analizama korišćenja energije za različite sisteme. Nacionalne studije i evropski pregledi ukazuju na ovaj jaz u poznavanju i dostupnosti sveobuhvatnih podataka koji ometa napore da se prate energetske karakteristike nestambenih zgrada, da se izrade odgovarajuće baze podataka i omogući modeliranje zgradarskog fonda. U prvom delu rada je prikazan pregled raspoloživih informacija i relevantnih pokazatelja u javno dostupnim bazama podataka u Evropi (npr. Eurostat, EU observatorija zgradarskog fonda, Odysee-Mure) i u SAD (npr. CBECS, ASHRAE). U drugom delu je dat pregled izračunatih intenziteta potrošnje energije za nestambene zgrade u Grčkoj, na osnovu podataka iz sertifikata o energetskim karakteristikama. Raspoloživi podaci su grupisani i analizirani za trideset namena zgrada, različite periode izgradnje i klimatske zone, kako bi bili izvedeni razni reperi ili standardi za merenje energije (benčmark). U skladu sa tim, prosečan intenzitet korišćenja primarne energije iznosi 513.4 kWh/m2, a emisije iznose 160.7 kgCO2/m2. Unutrašnje sportske dvorane i bazeni su objekti sa najvećim intenzitetom korišćenja energije, dok škole koriste najmanje energije, zbog rasporeda njihovog rada. Osvetljenje je sistem koji troši najviše energije, a slede hlađenje, grejanje prostora i vrlo malo korišćenje energije za grejanje sanitarne tople vode. Ključne reči: intenzitet korišćenja energije, nestambene zgrade, merenje performansi (benčmark) –––––––––––––––––––– *

Corresponding author’s e-mail: [email protected]

48. MEĐUNARODNI KONGRES I IZLOŽBA O KGH •

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There are about 6.2 billion m2 of useful floor space of non-residential (NR) buildings in Europe, consuming 141.2 Mtoe or 13.3% of the total final energy use. The NR building sector is more complex and heterogeneous compared to residential buildings and as a result the available information on the NR building stock is very limited, lacking specific data on building floor areas, construction characteristics, energy use breakdown for different services. National studies and European surveys underline this gap of knowledge and the limited availability of comprehensive data that handicap the efforts to track the energy performance of NR buildings, develop appropriate databases and facilitate building stock modeling. The first part of the paper will present an overview of available information and relevant benchmarks in publically accessible databases in Europe (e.g. Eurostat, EU building stock observatory, Odysee-Mure) and the United States (e.g. CBECS, ASHRAE). The second part will summarize the calculated energy use intensities for NR buildings in Greece, using data from energy performance certificates. The available data is clustered and analyzed for thirty building uses, different construction periods and climate zones, to derive various energy benchmarks. Accordingly, the average primary energy use intensity is 513.4 kWh/m2 and emissions reach 160.7 kgCO2/m2. Indoor sports halls and swimming pools are the most energy intensive facilities, while schools have the lowest energy use, due to their operational patterns. Lighting is the most energy consuming service, followed by cooling, space heating and a very low domestic hot water use. Key words: EUI, non-residential buildings, benchmarks

1. Introduction Non-residential (NR) buildings in Europe are estimated at 7 billion m2 of useful floor area and account for about a quarter of the total European building stock [1]. Final energy consumption in EU-28 non-residential buildings reached 146.9 million tonnes of oil equivalent (Mtoe) or 13.6 % of the total, according to the latest officially reported data for 2015 [2]. The member states with the highest energy use in NR buildings (Figure 1) are Germany (34.7 Mtoe), France (22.5 Mtoe), United Kingdom (16.3 Mtoe), Italy (15.4 Mtoe) and Spain (10.4 Mtoe). In terms of the percentage of NR buildings’ final energy consumption to the total energy consumption (%) the highest burden occurs in Malta (22.1% of the total), Estonia (16.8%), Germany (16.4%), France (15.6%) and Latvia (15.4%). For information, in Serbia, the final energy consumption in NR buildings is about 0.73 Mtoe or 9.7% of the total. In the United States of America, it is estimated that there are over 5.6 million NR buildings comprising 8.1 billion m2 of floor space [3]. Their final energy consumption in 2015 was 208.6 Mtoe or 14.7 % of the total final energy use in the United States [4]. Over the past 20 years, the EU-28 total final energy consumption has remained practically stable from 1082.8 Mtoe in 1995 to 1084.0 Mtoe in 2015 [2]. Over this period, the final energy use in the buildings sector (residential and NR buildings) has increased by 5.6%, from 399.8 Mtoe in 1995 to 422.1 Mtoe in 2015. Several European policies and national legislation, along with technical advances and impro370 • 48. INTERNATIONAL HVAC&R CONGRESS AND EXHIBITION

ved system and equipment performances, have contributed to the efforts to curb the escalation of energy use in buildings. For example, the energy performance of buildings Directive (EPBD 2002/91/EC and the EPBD recast 2010/31/EC), the Energy Efficiency Directive (EED 2012/27/EU), the promotion of renewables for power generation (2001/77/EC) and the Renewable Energy Directive (RED 2009/28/EC), and the ongoing efforts to transform the market of energy related products (ERPs) and energy-using products (EUPs) through the Ecodesign Directive (2005/32/EC and ECODESIGN recast 2009/125/EC). The final energy use in residential buildings has declined by 3.6%, although this may also be attributed to the economic crisis around 2010. At the same time, the final energy consumption in NR buildings has boomed by 28.5%, from 114.3 Mtoe in 1995 to 146.9 Mtoe in 2015. Non-residential buildings have different end-uses (e.g. space Heating, Ventilation and Air Conditioning (HVAC) systems, hot water, lighting, equipment and plug loads, vertical transportation etc) that may provide complex services. Common NR building types include retail and wholesale buildings representing 28% of the European non-residential building stock floor area [1], offices (23%), education (17%), hotels and restaurants (17%), health care (7%), sports facilities (4%) and other uses (11%).

Figure 1. Final energy consumption (Mtoe) in EU-28 non-residential buildings and ratio (%) of the NR buildings’ final energy consumption to the total. The bubble size represents the total final energy use in each EU member state. The inserted doughnut charts summarize the final energy consumption by sector in the EU (left) and the USA (right) In the USA, the total final energy consumption has increased from 1237.0 Mtoe in 1995 to 1396.8 Mtoe in 2015 [4]. Over this period, the final energy use in the buildings sector has increased by 11.6%, from 421.0 Mtoe in 1995 to 469.8 Mtoe in 2015. Specifically, the final energy use in residential buildings has increased by 5.4% and escalated by 20.4% in NR buildings, from 173.3 Mtoe in 1995 to 208.6 48. MEĐUNARODNI KONGRES I IZLOŽBA O KGH •

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Mtoe in 2015. However, despite a 14% increase in total NR buildings and a 22% increase in total NR floor space since 2003, the final energy use in 2012 was up just 7% [3]. This is attributed to the more strict US energy performance standards of new buildings, less energy intensive building activities, and more often as a result of new construction activity in regions with temperate weather conditions. The improved efficiency of key energy-consuming equipment is also decreasing demand. For example, since 2003, space heating and lighting are each down by 11% in their share of energy use in buildings. Common NR building types include offices (18% of the US non-residential building stock floor area [3]), retail and wholesale buildings (18%), warehouse and storage (15%), education (14%), hotels and restaurants (10%), public assembly (6%), health care (5%) and other uses (14%). Beyond the anticipated diversity of specific end-uses for different NR building types, lighting and HVAC constitute the most important energy end-uses (Figure 2).

Figure 2. Average energy use breakdown for NR buildings in the EU and the US Although the NR building sector has a fast growing energy demand, comprehensive information and detailed data on key determinants that influence the buildings’ energy use are limited in Europe. Data collection is a time-consuming process given that is burdened even more given the difficulties in tracking the numerous NR building types, the variability of services and technical installations, the diversity in operating hours, the overall design, etc. This gap of detailed knowledge constitutes a major handicap in the efforts to monitor the energy performance of NR buildings, facilitate building stock modeling and the assessment of energy conservation measures in order to develop appropriate policies. Benchmarking energy use by comparing a building’s normalized energy consumption to that of peer buildings can be a useful first measure of energy efficiency [5]. Benchmarks can also be used as self-reference over time to assess performance before and after the implementation of energy retrofits. The size, vintage (since the construction period relates to different construction practices), geographic region, 372 • 48. INTERNATIONAL HVAC&R CONGRESS AND EXHIBITION

and principal activity of a building (for the different building types) are among the key determinants that influence its energy use. Relative energy use is commonly expressed by the energy use intensity (EUI) that is defined as the building’s annual energy use per unit floor area. EUIs are usually clustered for different building types, vintage and locations, which are also common attributes in building Census or national statistical surveys, and can be used to populate national building stock modeling efforts along the lines of similar work for residential buildings [6]. In this context, one valuable resource to extract relevant data is from the energy performance certificates (EPC) that are being issued throughout Europe in compliance with EPBD. Along these lines, several studies have emerged that exploit this information to map the characteristics of NR buildings in several European countries [7-9]. The first part of the paper provides an overview of publically available databases in Europe and the USA for various NR building types, focusing on energy use, floor areas, construction characteristics, breakdown for different end-uses etc. The second part presents relevant benchmarks derived from the analysis of data from EPCs that have been issued in Greece for thirty NR building types.

2. Data for EU & US Non-Residential Buildings Data collection on the energy performance of buildings is a very time consuming process and a lot of times there are inconsistencies and issues with data quality and the availability of detailed information in order to develop suitable benchmarks, especially for NR buildings. Information may be available at different formats since they are extracted from different sources, and sometimes they may even be conflicting. This section summarizes available information and relevant benchmarks from publicly accessible databases in Europe and the United States. 2.1. EU Resources In Europe, the total final energy consumption in NR buildings averages 280 kWh/m2 (about 40% greater than the corresponding average value for the residential sector), while electricity use over the last 20 years has increased by 74% [1]. The variations of specific energy use for different NR building types are significant. For example, hospitals at 252-434 kWh/m2 have the highest EUIs due to the continuous occupancy, high-energy specific operations and space functions, while they represent 10% of the total energy use in the NR building sector. Hotels & restaurants with 213-426 kWh/m2 represent 12% of the total energy use in the NR building sector. More than half of the energy used in European NR buildings is by wholesale & retail trade buildings (200-335 kWh/m2 or 28% of the total) and offices (205-316 kWh/m2 or 26% of the total). Education with 142-243 kWh/m2 (12%), sports facilities with 110-255 kWh/m2 (6%) and all other buildings at 6% makeup the rest. Detailed data on the energy performance of buildings across Europe are publically available from: 1) Eurostat, the statistical office of the European Union providing high quality statistics for Europe [10]. It provides data for the total NR building stock under “Services”, including the energy consumption and emissions of all NR buil48. MEĐUNARODNI KONGRES I IZLOŽBA O KGH •

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dings (as an aggregate) and the breakdown by energy carriers. Eurostat does not provide detailed data for specific building types. 2) EU Building Stock Observatory, under the jurisdiction of the DirectorateGeneral for Energy [11]. It provides a broad snapshot of the building stock characteristics in EU-28 and includes data from EU projects, national statistics, EPC databases, cities’ sustainable energy action plans, industry data, and other sources, with factsheets on specific topics per country. The database contains raw data that comes from different sources like Eurostat, Odyssee and other national organizations like the Joint Research Centre, Danish Energy Agency, CEREN (France), AGEB (Germany) and the European Investment Bank (EIB). Detailed data for the different building types are available for ten countries (i.e. Bulgaria, Estonia, France, Germany, Malta, Netherlands, Romania, Spain, Sweden and United Kingdom). 3) Odyssee-Mure databases coordinated by the French Environment and Energy Management Agency (ADEME) and co-funded by Horizon 2020 programme of the European Commission, a network of 37 partners from 31 countries, usually national energy efficiency agencies [12]. The Odyssee database (managed by Enerdata) includes information on energy efficiency indicators and energy consumption by end-use and their underlying drivers in buildings and other sectors. Detailed data is available for only seven European countries (i.e. Denmark, Finland, France, Germany, Greece, Spain, Sweden). The Mure database (managed by Isinnova) focuses on energy efficiency policies and measures by country. Access to the data is free for non-commercial use in Europe and via subscription for other users. The available data (Table 1) include among others: floor area, number of NR buildings, distribution between different types of NR buildings and their respective floor area, buildings by construction year, construction details for building envelope components (e.g. U-values), final energy use in NR buildings during different periods of time for some countries, energy carriers and different end-uses, direct and indirect emissions etc. The NR buildings in the EU Observatory and Odyssee databases are split into five different NR building types: Offices (O), Wholesale and Retail trade buildings (W&RT), Hotels and Restaurants (H&R), Health care buildings (HC) and Educational buildings (E). Both databases provide information for the different energy carriers: gas, oil, coal, electricity, heat and wood in Odyssee and renewables in the EU Observatory database. Similarly, they both include the breakdown by end-use: space heating, cooling, water heating, lighting and cooking. Typical benchmarks like EUI (kWh/m2) can be derived from the available data in order to assess the general energy performance of different buildings types. This can be based on average values between different countries during a certain period, or consider their time evolution in a given country. Similarly, the environmental impact of NR buildings can be assessed by expressing the emissions per unit floor area. However, not all resources have the same amount of data and for some parameters there are inconsistencies between the various resources.

374 • 48. INTERNATIONAL HVAC&R CONGRESS AND EXHIBITION

Table 1 Overview of available data from European resources EUROSTAT

EU Building Stock Observatory

ODYSSEE

Building stock characteristics Number of all NR

  (O, W&RT, H&R, HC, E)*

Number of different types of buildings Share of all NR by age



Floor area of all NR



Floor area of different types of buildings

 (O, W&RT, H&R, HC, E)*

Annual construction of buildings (Mm2 of new buildings)



Building envelope performance U-values per building element for all NR and vintage



Final energy consumption All NR





  (O,W&RT,H&R,HC,E)* (O,W&RT,H&R,HC,E)*

Different building types All NR by energy carrier













 (Space heating, Water heating)

 ( Space heating, Water heating)

 (Lighting)

 (Lighting)

All NR per m²





All NR per m² for and by end-use





All NR by end-use All NR by energy carrier for different end-uses Building types and by end-use

Emissions CO2 from direct fuel combustion in all NR Total CO2 emissions (including electricity) in all NR



 

* Building types: * O: Offices (private offices and public office buildings); W&RT: Wholesale and Retail trade; H&R: Hotels and Restaurants; HC: Health care: E: Education. 48. MEĐUNARODNI KONGRES I IZLOŽBA O KGH •

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According to the available data from [11], the total number of NR is ∼11.8 million buildings with a total floor area of ∼7 billion m2. Wholesale and retail buildings account for about half of the building stock (Figure 3), followed by 27.6% for offices, 10% hotels and restaurants, 7.2% education and 5.2% health care. Specific data breakdown for NR buildings by vintage are available for only Austria, Hungary, Belgium and Germany, averaging 64.2% for pre-1980, 18.3% for 19801990, 19.1% for 1990-2010 and 3.6% post 2010. However, there is no available data for the specific buildings age breakdown for different NR building types. Gas energy consumption represents the highest share of energy use in buildings (residential and non-residential) on the EU level (36%) and it represents the largest consumption in several countries, e.g. about half in Italy, United Kingdom and Hungary and above 60% in the Netherlands. The use of electricity averages 32% at EU-28 and reaches 70% in Malta.

Figure 3. Distribution of the number of buildings for the main NR building types (up) and floor areas for different NR building types (down) in Europe (Data for 2013 from [11])


The final EUI (kWh/m2) for different NR building types can only be generated for a limited number of countries for which the energy use and total floor area is available (Table 2). Table 2. Final energy use intensities (kWh/m2) for NR building types in European countries (Data for 2013 from EU Building Stock Observatory [11] / Odyssee [12]) Country

Offices

Wholesale & Retail

Hotels & Restaurants

Health care

Education

Austria

All NR (normal climate) 145.8 / -

Belgium

298.1 / -

Bulgaria

77.8 / -

96.5 / -

656.5 / -

219.3 / -

130.6 / -

Czech Republic

201.4 / -

Croatia

239.9 / -

Cyprus

291.3 / -

Denmark

201.6 / 182.0

Estonia

479.6 / -

70.7 / -

147.8 / -

217.4 / -

Finland France Germany

403.1 / 292.6 / 273.5

- / 280.9

255.8 / 256.7 391.0 / 393.3 228.2 / 232.4 143.6 / 154.5 276.1 / 240.1

130.8 / 154.5 151.3 / 148.3 212.3 / 201.5 317.2 / 328.5

108.5 / 98.2

238.6 / 187.0

Greece

300.1 / -

Hungary

203.7 / -

Ireland

186.4 / -

Italy

652.5 / -

Latvia

302.7 / -

Lithuania

136.9 / -

Luxembourg

350.4 / -

Malta

234.9 / -

394.2 / -

302.1 / -

Netherlands

356.8 / -

174.1 / -

380.8 / -

436.6 / 237.8 / -

127.8 / -

149.0 / -

Poland

190.7 / -

Portugal

196.4 / -

Romania

345.0 / -

Slovakia

202.4 / -

Slovenia

387.5 / -

Spain Sweden UK

409.4 / -

46.1 / -

1124.3 / -

355.1 / -

318.8 / 316.9

132.3 / 255.9 114.0 / 376.2 263.5 / 326.7 230.6 / 214.4 134.4 / 161.7 226.3 / 269.6 278.8 / -

213.9 / -

314.3 / -

516.2 / -

237.6 / -

251.5 / -


377

Table 2 also includes the average final energy intensity for the NR building sector (All NR building types) for normal climate, i.e. with climatic corrections for the space heating contribution that corresponds to normal winter conditions based on heating degree days. There is a large variation of EUIs, averaging 269.2±108.9 kWh/m2 for the EU-28, with a median at 245.7 kWh/m2. As expected, the highest EUIs are reported in health care buildings that have the most demanding specific requirements for HVAC, followed by hotels. Retail buildings and offices have comparatively lower EUIs since they are maintained at more recent and better building standards [1]. Space heating is the main end-use, representing 61.1% of the total final EUI (Figure 4), followed by lighting (12.2%), cooking (12.0%), water heating (10.5%) and space cooling (4.2%). There are notable differences between the breakdowns reported by [12] in Figure 2 and [11] in Figure 4, and the EUIs in Table 2.

Figure 4. Breakdown of final energy use intensity (kWh/m2) for different end-uses in Europe (Data from [11]) Eurostat does not provide specific data about the NR building stock characteristics (e.g. different building types, vintage, etc). The EU Building Stock Observatory [11] is the most comprehensive database that provides detailed data on the number of buildings, the share of buildings by vintage, the floor areas etc, for all the EU-28 member states. On the other hand, Odyssee [12] provides data on the buildings floor areas but is limited to only seven European countries. Both resources provide the same floor area of NR buildings in France, Spain and Finland, but there are small deviations (∼5%) in reported floor area for Germany and Denmark, which may be attributed in part to number rounding and incomplete reporting of data. The largest deviations are observed for Sweden and Greece, with Odyssee reporting very conservative data. The historical records of data on the final energy use for the NR buildings sector in Eurostat and Odyssee are longer than the 2000-2014 periods available from EU Building Stock Observatory. Although the EU Observatory exploits raw data from Eurostat, the corresponding values are not identical and the small deviations (less than 0.5% on annual data) are attributed to rounding errors, since Eurostat uses four decimal digits of precision instead of two used by the EU Observatory. On an 378 • 48. INTERNATIONAL HVAC&R CONGRESS AND EXHIBITION

annual basis this difference is slightly larger (∼2%) between Eurostat and Odysee for their common periods. Large deviations are noted for Malta (about 74% for Eurostat-Odyssee) which may be anticipated since this refers to a small value of total energy consumption (less than 2 Mtoe). Similar issues also occur for Germany, France and Italy for which the differences among the EU Observatory-Eurostat and Odyssee data exceed 20%, which is equivalent of up to 7 Mtoe). Looking at the differences for the breakdown of different energy carriers among the EU Observatory-Eurostat and Odyssee data, major deviations are reported for the use of oil in the UK (51% with ∼3 Mtoe difference), gas in Italy (50% with ∼4 Mtoe difference) and oil in Sweden (117 % with ∼0.25 Mtoe difference). Some of the differences may be attributed to the accounting system of different energy carriers, e.g. accounting for waste heat, wood and other renewables. Figure 5 summarizes the generated benchmarks for the final energy use intensities and the breakdown for different end-uses in the European countries that have commonly available data from the two resources.

Figure 5. Comparison of final energy use intensities (kWh/m2) for different building types (left) and end-uses (right) in representative European countries (Data for 2013 from [11] and [12]) 2.2. US Resources The main resource of building energy performance data is the Commercial Buildings Energy Consumption Survey (CBECS). It provides detailed information on energy-related building characteristics and measured EUIs based on a national sample survey of more than 6,700 U.S. commercial buildings (e.g. hotels and lodging, offices, restaurants, stores, warehouses) and other non-residential uses (e.g. schools, hospitals, correctional institutions) [3]. The data is broken down by building size, age, principal building activity, region, climate zone and other building attributes. The latest CBECS survey was conducted in 2012. The total final energy consumption in US non-residential buildings reached 250.7 Mtoe in 2012, of which 152.7 Mtoe of electricity, 80.9 Mtoe of natural gas, 48. MEĐUNARODNI KONGRES I IZLOŽBA O KGH •

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4.8 Mtoe of fuel oil and 12.3 Mtoe of district heat. Electricity and natural gas usage increased by 19% and 7%, respectively, since 2003, while fuel oil and district heat usage decreased by 41% and 46%, respectively. Overall, electricity and natural gas are the two dominant energy sources in the US non-residential buildings sector, accounting for about 93% of total final energy consumed in 2012. Along with the increase in total electricity consumption, electricity increased its share from 38% in 1979 to 61% in 2012 [3]. The share of natural gas used was larger than 44% in 1979 and dropped at 32% in 2012. Fuel oil’s share has dropped from 14% in 1979 to only 2% in 2012. In the US, the average total final energy used dropped from 287.0 kWh/m2 in 2003 to 252.0 kWh/m2 in 2012. The average electricity EUI at 153.6 kWh/m2 remained about the same since 2003 (156.7 kWh/m2), but decreased for natural gas (from 92.4 kWh/m2 in 2003 to 81.4 kWh/m2 in 2012), fuel oil (from 10.1 kWh/m2 in 2003 to 4.7 kWh/m2 in 2012) and district heat (from 28.1 kWh/m2 in 2003 to 12.3 kWh/m2 in 2012). The decrease in natural gas EUI is likely related to federal equipment standards over that time period and warmer-than-average winter months of the survey year 2012 [3]. Specific EUIs for various NR buildings are illustrated in Figure 6.

Figure 6. Final energy use (kWh/m2) for different building types in the USA


Food service, inpatient health care (hospitals), and food sales buildings are the most energy intensive users. Food service buildings, which include convenience stores, tend to be small but use relatively large amounts of energy for cooking and refrigeration, while many of them are often operated for long hours. Hospital energy use is high because of around-the-clock demand for all end uses and because of a wide variety of specialized, energy intensive medical equipment. Total energy use from the CBECS data is divided into end uses through statistically-adjusted engineering models to estimate end uses for electricity, natural gas, fuel oil, and district heat. For these four energy sources combined, CBECS produces estimates for ten end-use categories: space heating, cooling, ventilation, water heating, lighting, cooking, refrigeration, computing, office equipment, and other use, which includes motors, pumps, air compressors, process equipment, backup electricity generation, and miscellaneous appliances and plug-load. The largest end-use share of total energy in 2012 was for space heating, followed by the other category (Figure 2). The CBECS data is the basis for many metrics, labels and policies for commercial buildings in the United States, including the Energy Star program (https://www.energystar.gov/buildings) that provides a benchmark to assess energy performance and identifies top performers with the Energy Star building label. The average final EUI for commercial buildings is 283.8 kWh/m2, with significant variations for different construction periods and locations. The aggregated CBECS data provides the basis to calculate the rating for ASHRAE’s building energy labeling program (http://buildingenergyquotient.org) and generate the building energy quotient (Building EQ) label, with letter grade rating scale similar to the European EPCs. The Building EQ performance score provides an “In Operation” rating that is based on the building’s metered energy use over 12 to 18 months, following an ASHRAE Level 1 energy audit. The bEQ In Operation assessment also provides building owners with building-specific energy savings measures with estimated costs and payback information that can be used to improve building energy performance. It can also provide a bEQ “As Designed” rating that is based on simulated performance with standardized inputs compared to a baseline EUI to evaluate a building’s potential energy use independent of its operation and occupancy. ASHRAE has also developed standard benchmark energy use intensities that present calculated EUIs for 16 different commercial buildings and different climate zones for pre- and post-1980 construction characteristics (http://cms.ashrae. biz/EUI). Benchmarks that are derived from measured energy use (calculated from CBECS) and expressed as EUI targets are also available for different U.S. commercial building types and climate zones [13].

3. Hellenic Non-Residential Buildings In Greece, there are about 785,500 exclusive-use NR buildings that represent 21% of the Hellenic building stock, with a total floor area of about 159 million m2 [14]. About 8% of the Hellenic building stock has a mixed-use (329,790 buildings) of which about 22.5% are buildings with NR main use. About 58% of the Hellenic 48. MEĐUNARODNI KONGRES I IZLOŽBA O KGH •

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buildings were built before 1980, the year that marks the introduction of the first Hellenic thermal insulation regulation (HBTIR), which was then revised in 2010 with the more strict national regulation on the thermal performance of buildings (KENAK) in line with the EPBD transposition in Greece [15]. As a result, the majority of the Hellenic buildings have no thermal protection and they are equipped with old and inefficient heat generation systems. The Hellenic NR buildings sector consumed 1.87 Mtoe in 2015 [2], but detailed breakdown information for the different building uses is limited to a few field and empirical studies [16-17], while detailed data is very abstract. A valuable resource of relevant information about the existing building stock is progressively becoming available from the energy performance certificate (EPC) that are being issued every year throughout Europe for thousands of existing and new buildings or building units when they are sold or rented out, in compliance with EPBD. This part of the work presents the results from an in-depth data analysis based on EPCs issued for NR buildings in Greece in order to gain a better understanding of the energy consumption of Hellenic non-residential buildings. The analysis derives relevant benchmarks for numerous NR building types, representative vintage and locations for the four different Hellenic climate zones (Figure 7). A qualified energy inspector performs the building energy audit to collect all relevant data and perform the analysis for issuing an EPC. All the input and output data are stored in an electronic repository (buildingcert). The normative calculations for estimating the building’s energy demand are performed with the national calculation software in accordance to the European standards using the quasi-steady state monthly method. The energy demand for the different end-uses includes HVAC and lighting, but does not include plug loads or other services. The energy class label for ranking the building’s energy performance on a letter-scale is determined by comparing the building’s calculated energy use against a reference building (i.e. a carbon copy of the studied building that automatically adapts the characteristics of its building elements and technical installations to meet the minimum energy code requirements). The two-page Hellenic EPC includes the building type, vintage (based on the construction period), location (in terms of the four national climate zones of the country), the total and heated areas, the energy class ranking, the calculated annual primary energy consumption (optionally actual energy consumption is included, if available), the resulting CO2 emissions, a breakdown of energy carriers and for the different services, along with up to three cost effective recommendations for improving the building’s energy performance [15]. In the normative calculations, primary energy is estimated using the national conversion factors for different energy carriers, i.e. 2.9 for electricity, 1.1 for heating oil and 1.05 for natural gas. The carbon emissions are estimated using the following national conversion factors: i.e. 0.989 kgCO2/kWh for electricity, 0.264 kgCO2/kWh for heating oil and 0.196 kgCO2/kWh for natural gas. Following a data quality check, the data set that was used for this work included ∼120,000 EPCs of which ∼18,500 EPCs for whole-buildings (e.g. a NR building with the same exclusive-use like a stand-alone office building) and ∼101,500 EPCs 382 • 48. INTERNATIONAL HVAC&R CONGRESS AND EXHIBITION

for part-buildings (e.g. an individually owned part of a building or a building unit that has specific non-residential use like an independent office within a multi-floor residential apartment building). The data set includes EPCs that have been issued in all four climate zones, but there is some bias since the majority of the certificates (∼54% of the total) originate from EPCs issued in climate zone B that includes Athens, which is the largest metropolitan region of Greece. The vast majority of the NR buildings in the data set are wholesale and retail (56%) and offices (18%). Most are old buildings, with 53% constructed pre-1980, 32% between 1981-2010, while only 2% are new constructions (post-2010) corresponding to the KENAK era. This breakdown is in-line with the latest building Census and statistics [14]. Table 3 summarizes the calculated primary EUIp as well as the corresponding CO2 emissions for the different building types according to the national regulation. Interpreting these benchmarks one needs to keep in mind that the normative calculations are performed using several standard operating conditions regarding their daily and annual operating hours, indoor conditions, standard weather datasets for 62 locations in Greece, etc. The default values minimize the uncertainties of model variants and reduce the complexity of the model calculations. The space heating period depends on location (i.e. defined in terms of the four national climate zones; from November to mid-April for climate zones A and B in the south, and from midOctober to mid-April for climate zones C and D in the north). The space cooling period is from mid-May to mid-September for climate zones A and B, and from June to August for climate zones C and D. The annual hot water demand is fixed at cubic meters per heated floor area or per bed (e.g. for hotels), while the mean hot water temperature is set at 45oC. For some building types (e.g. schools) the hot water consumption is considered negligible and is not part of the load calculations. The minimum fresh air requirements are covered only by mechanical ventilation. The infiltration rate from openings ranges between 4.8-15.1 m3/h/m2 of the opening, depending on the type of the opening, glazing and frame. The standard input values and assumptions that are used in the calculations vary depending on the building type. For example, the calculations for sports halls are based on continuous operation (14 h/day, 365 days/year) and 5096 hrs for artificial lighting, an indoor set-point temperature at 18oC and 35% relative humidity in winter and 25oC and 45% in summer, a hot water consumption at 3.29 m3/m2 at 45oC, an infiltration rates at 33.75 m3/h/m2 floor area, the internal heat gains from lights at 9.6 W/m2, people at 52.2 W/m2 and equipment at 0.58 W/m2, with an occupancy correction factor of 58%. Furthermore, according to the national methodology, the energy calculations for NR buildings do not consider office equipment and other plug loads, along with miscellaneous equipment and process loads (e.g. elevators, escalators, data center and telecom room computing equipment).


383

Table 3. Primary and final energy use intensities (kWh/m2) and emissions (kgCO2/m2) for whole- and part-buildings Building Types

Primary Emissions Emissions No No Final No Primary No Final (kWh/m2 (kgCO2/m 2 2 (kgCO2/m EPC EPC (kWh/m ) EPC (kWh/m ) EPC (kWh/m2) 2 2 ) ) ) Whole-Buildings

Part-Buildings

Hotel (annual)

541

650.8

205.1

429

310.6

237

717.5

224.1

211

343.1

Hotel (summer)

1433

384.7

124.9

1177

146.6

609

376.3

121.2

542

143.6

Guest house (annual)

621

663.9

209.4

562

318.4

431

697.3

223.1

411

325.2

Guest house (summer)

1291

383.1

123.3

1213

141.3

813

375.1

121.7

780

137.1

Guest house (winter)

6

554.3

167.1

6

336.2

3

690.1

138.5

3

437.7

Boarding / Dorms

28

691.2

205.7

26

348.4

49

640.0

200.5

46

328.5

Restaurant

1857

848.5

263.5

1670

396.8

4908

786.4

248.1

4558

351.4

Pastry / Coffee shop

1750

930.9

281.2

1595

467.0

7393

833.7

263.2

6903

373.4

Night / Music hall

400

341.6

107.9

371

157.2

547

326.3

103.2

520

136.4

Theater / Cinema

31

380.1

124.0

29

165.8

58

350.2

114.4

51

159.3

Exhibition / Museum

63

312.0

101.8

56

145.0

82

355.0

116.9

78

152.2

Conference hall/Court

9

672.0

224.9

9

268.3

28

351.9

114.5

25

159.5

Bank

38

281.0

92.3

36

113.5

200

281.9

94.4

185

109.8

Multi purpose

172

362.2

116.9

158

166.0

499

328.4

107.1

476

149.4

Sports hall / Pools

150

1028.3

322.4

126

556.0

475

953.6

309.9

444

430.6

Kindergarten

106

179.3

50.5

98

128.0

92

147.2

42.3

78

84.8

Schools

693

170.6

48.9

652

121.2

158

180.4

54.0

150

112.9

Universities

64

336.8

110.5

56

148.7

302

274.0

89.8

284

127.3

Private cram school

116

200.1

63.6

102

107.0

1602

183.7

57.8

1480

97.6

Hospital/ Clinic

80

741.5

227.6

55

434.0

55

625.0

194.3

38

290.5

Health care / Clinics

138

513.1

161.3

123

257.4

2614

430.3

138.7

2452

195.1

Nursing home/Asylum

72

736.4

224.6

58

429.2

29

758.1

241.2

29

360.6


Building Types

Primary Emissions Emissions No No Final No Primary No Final (kWh/m2 (kgCO2/m 2 2 (kgCO2/m EPC EPC (kWh/m ) EPC (kWh/m ) EPC (kWh/m2) 2 2 ) ) )

Nursery

199

272.9

85.2

182

150.2

167

249.1

77.1

162

137.7

Police station

10

558.2

173.8

10

302.1

17

742.3

240.2

14

346.6

Malls/Large retail

282

397.0

131.2

259

161.3

728

461.5

151.6

705

197.6

Small retail/Drugstore

6580

504.5

161.4

6257

236.5

58659 434.0

140.5

5652 3

197.7

Fitness center

33

692.3

218.4

29

309.2

596

711.8

230.0

566

318.6

Barber/Hair salon

34

690.9

219.3

32

340.5

911

546.2

179.7

865

224.8

Office

1681

374.4

121.2

1500

166.8

19333 346.5

112.9

1848 3

151.9

Library

13

310.5

94.2

11

179.0

310.2

97.6

20

151.6

170.0

1687 7

10161 463.0 6

149.2

Total or Avera18491 539.5 ge

250.3

21

97082 224.4

The calculated average (median value in parenthesis) annual primary energy use intensity of all NR buildings is 539.5 (442.6) kWh/m2 for whole-buildings and 463.0 (391.9) kWh/m2 for part-buildings. The average calculated EUIp per building type ranges from 170.6 kWh/m2 to 1028.3 kWh/m2 for whole-buildings and from 147.2 kWh/m2 to 953.6 kWh/m2 for part-buildings. The average CO2 emissions range from 48.9 kgCO2/m2 to 322.4 kgCO2/m2 for whole-buildings and from 42.3 kgCO2/m2 to 309.9 kgCO2/m2 for part-buildings, averaging 170.0 kgCO2/m2 and 149.2 kgCO2/m2, respectively. Apparently, the calculated EUIs should be adapted to account for example for the actual (unique) building characteristics, operating conditions, occupant behavior and local weather data that deviate from the specifications in the calculations. Empirical adaptation factors that relate the normative calculated primary heating energy consumption from the EPCs with the actual energy use can be derived by defining the ratio of f(actual/calculated) energy use. Depending on the availability of data (e.g. optional information that is sometimes included in the EPC, if available), these ratios can be defined for specific building typologies (e.g. building types, vintage, climate zones) and use them as multiplicative factors to make more realistic estimates of the actual energy use. Representative adaptation factors for whole-buildings average 0.83 (i.e. actual heating energy use is 17% lower than calculated) for schools and 1.31 (i.e. actual heating energy use is 31% higher than calculated) for offices [18]. Energy consumption is influenced by vintage, decreasing from older buildings (e.g. not thermally insulated, with inefficient equipment) to newer ones (e.g. better thermal envelope protection and equipped with more energy efficient equipment). Primary energy consumption averages 512.3 kWh/m2 for pre-1980 buildings (considered not thermally insulated), 450.7 kWh/m2 for 1981-2000 period 48. MEĐUNARODNI KONGRES I IZLOŽBA O KGH •

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(i.e. partly thermally insulated buildings according to HBTIR), 401.9 kWh/m2 for 2001-2010 period (i.e. insulated in compliance with HBTIR) and 306.5 kWh/m2 for the new buildings after 2010 that corresponds to the most recent strict requirements of the KENAK era. Location relates to the prevailing weather conditions, which is one of the main driving factors of building energy performance. In Greece, there are four climate zones according to the national energy code (Figure 7). Climate zone A in the south includes most of the Hellenic islands and is the mildest portion of the country (averaging only 859 heating degree days - HDD and 2502 cooling degree hours CDH), to zone D in the north with the coldest conditions (averaging 2306 HDD). The average calculated EUIp for each climate zone is included in Figure 7or wholebuildings and for part-buildings. Analysis for the different end-uses revealed that lighting is the most consuming service (38%), followed by cooling (32%), space heating (26%) and hot water (4%). Electricity is the main energy carrier, followed by fuel oil and low natural gas use. The exploitation of solar thermal energy is significant in hotels (39% of the buildings) and hospitals (14% of the buildings), but overall is limited to only 4% in offices and 3% in schools.

Figure 7. The four Hellenic climate zones and the corresponding average calculated primary energy use intensity (kWh/m2) for NR whole- / part-buildings A similar analysis was followed for deriving the average annual final energy use intensity from the calculated values in the EPCs. The available EPC dataset was screened for this part of the work in order to select cases that use only one energy carrier source for space heating or space heating and DHW, in order to estimate the final energy consumption. The results are summarized in Table 3. The available dataset reached 16,877 cases for whole-buildings and 97,082 cases for partbuildings. The calculated average (median value in parenthesis) annual final energy use intensity of all NR buildings is 250.3 (213.7) kWh/m2 for whole-buildings and 224.4 (186.3) kWh/m2 for part-buildings.


4. Conclusions This work identified and analyzed detailed European and US information and data from various publicly available sources, on NR buildings and energy consumption. One of the main objectives was to investigate the level of detail of the available data for NR buildings, for different types of buildings (e.g. offices, schools, hotels), energy carriers, different end-uses, etc. The available data was then analyzed and compiled in order to derive common indicators and compare relevant benchmarks from the various sources (e.g. energy use intensities in kWh/m2 and emissions). Various gaps and inconsistencies were revealed and discussed. The analysis also identified gaps and some inconsistencies amongst the different European data resources. The CBECS data from the United States is a detailed and valuable resource for non-residential buildings. Figure 8 illustrates the EUIs for selected NR building types from the different resources elaborated in this work. One should exercise caution interpreting and using the EUIs since they have been derived from different databases and actual or calculated operating conditions. For example, the CBECS data is based for actual final energy use data for the US commercial buildings (e.g. including plug loads, computing, etc). The differences of the EUIs derived from the different European resources reveal significant deviations in some cases. The values for the various EU28 member states were calculated as an average of the EU Building Stock Observatory and Odyssee data included in Table 2. For Italy, the estimated EUI at 652.5 kWh/m2 raises some concerns about the accuracy of the raw data. The average final energy use intensity for European NR buildings is 268.3 kWh/m2 and 252.0 kWh/m2 for the US commercial buildings.

Figure 8. Average final energy use intensity (kWh/m2) for NR buildings in the EU and the USA, and the ratio (%) of the NR buildings’ final energy consumption to the total. The bubble size represents the total final energy use 48. MEĐUNARODNI KONGRES I IZLOŽBA O KGH •

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For the Hellenic NR buildings, the calculated average final energy use intensity is 250.3 kWh/m2 and the emissions reach 170.0 kgCO2/m2, based on data from the EPC dataset. This complementary EUI is also included in Figure 8 for comparison; this is indicated with the additional bubble point for Greece (EPC) to differentiate it from the other data derived from the European resources. Although, at this stage, the available number of EPC cases in Greece may not be satisfactory for all building types, it appears that the national registry of certificates is a valuable resource of data for gaining a better insight of the Hellenic NR building stock. As the EPC database is progressively populated with new data it will be possible to refine and update, where necessary, the derived benchmarks. Additional work that is currently underway is investigating the anticipated deviations between calculated and actual energy in order to develop empirical adaptation factors for specific NR building types, thus enhancing the accuracy of a national building stock model.

5. Acknowledgments Part of this work was carried out by Ms. Droutsa in partial fulfilment of the requirements for a PhD Dissertation at the Department of Physics, University of Patras, Greece, and by Ms. Micha in partial fulfilment of the requirements for an MSc Thesis in Energy Systems at the Department of Mechanical Engineering, ATEI of Pireaus, Greece and the School of Engineering and Physical Sciences, HeriotWatt University, Edinburgh, UK. The official national EPC repository in Greece (www.buildingcert.gr) has been developed and is maintained by the Hellenic Ministry of Environment & Energy (YPEN) in collaboration with the Centre for Renewable Energy Sources (CRES). The authors wish to thankfully acknowledge YPEN for allowing access to the national EPC database. The analysis performed by the authors does not necessarily reflect the opinion of the Ministry.

6. References [1] Economidou M., B. Atanasiu, C. Despret, J. Maio, I. Nolte, O. Rapf, Europe’s buildings under the microscope. A country-by-country review of the energy performance of buildings, Brussels: Buildings Performance Institute Europe (BPIE), 2011. http://www.bpie.eu/uploads/lib/document/attachment/20/HR_EU_B_under_microscope_ study.pdf [2] *** EU, European Union Energy in Figures – Statistical Pocketbook 2017 edition, Brussels: European Commission. https://ec.europa.eu/energy/sites/ener/files/documents/pocketbook_energy_2017_web.pdf [3] *** CBECS, Commercial Buildings Energy Consumption Survey, US Department of Energy. https://www.eia.gov/consumption/commercial/ [4] *** IEA, Energy Balances – Statistics, Paris: International Energy Agency, 2015. http://www.iea.org/statistics [5] *** ASHRAE, Chapter A36, Energy Use and Management, ASHRAE Handbook – HVAC Applications, Atlanta: ASHRAE, 2015.


[6] Visscher H., E. Dascalaki, I. Sartori (editors), Towards an energy efficient European housing stock: Monitoring, mapping and modelling retrofitting processes, Energy and Buildings 132 (2016), pp. 1-154. https://doi.org/10.1016/j.enbuild.2016.07.039 [7] Godoy-Shimizu D., P. Armitage, K. Steemers, T. Chenvidyakarn, Using Display Energy Certificates to Quantify Schools’ Energy Consumption, Building Research & Information 39 (2011), pp. 535-552. 1371 http://dx.doi.org/10.1080/09613218.2011.628457 [8] Armitage P., D. Godoy-Shimizu, K. Steemers, T. Chenvidyakarn, Using Display Energy Certificates to Quantify Public Sector Office Energy Consumption, Building Research & Information 43 (2014), pp. 691-709. http://dx.doi.org/10.1080/09613218.2014.975416 [9] Gangolells M., M. Casals, N. Forcada, M. Macarulla, E. Cuerva, Energy mapping of existing building stock in Spain, Journal of Cleaner Production 112 (2016), pp. 38951361. http://dx.doi.org/10.1016/j.jclepro.2015.05.105 [10] *** Eurostat, Statistical Office of the European Union, Luxembourg: European Commission. http://ec.europa.eu/eurostat/web/main [11] *** EU Building Stock Observatory, Brussels: European Commission, DG Energy. https://ec.europa.eu/energy/en/eubuildings [12] Odyssee-Mure, A decision-support tool for energy efficiency policy evaluation. http://www.indicators.odyssee-mure.eu/ [13] *** ASHRAE, ANSI/ASHRAE/ IES Standard 100 - Energy Efficiency in Existing Buildings, Atlanta: ASHRAE, 2015. https://www.ashrae.org/resources-publications/bookstore/standard-100 [14] *** ELSTAT, Buildings Census 2011, Athens: Hellenic Statistical Authority, 2015. www.statistics.gr/census-buildings-2011 [15] Dascalaki E.G., C.A. Balaras, A.G. Gaglia, K.G. Droutsa, S. Kontoyiannidis, Energy performance of buildings – EPBD in Greece, Energy Policy 45 (2012), pp. 469-477. http://dx.doi.org/10.1016/j.enpol.2012.02.058 [16] Gaglia A.G., C.A. Balaras, S. Mirasgedis, E. Georgopoulou, Y. Sarafidis, D.P. Lalas, Empirical Assessment of the Hellenic Non-Residential Building Stock, Energy Consumption, Emissions and Potential Energy Savings, Energy Conversion & Management 48 (2007), pp. 1160-1175. http://dx.doi.org/10.1016/j.enconman.2006.10.008 [17] *** YPEKA, National Energy Efficiency Action Plan Pursuant to Article 24(2) of Directive 2012/27/EU, Athens: Hellenic Ministry of Environment, Energy and Climatic Change, 2014. http://ec.europa.eu/energy/en/topics/energy-efficiency/energy-efficiencydirective/national-energy-efficiency-action-plans [18] Droutsa K.G., S. Kontoyiannidis, E.G. Dascalaki, C.A. Balaras, Benchmarking Energy Use of Existing Hellenic Non-Residential Buildings, Procedia Environmental Sciences 38 (2017), pp. 713-720. http://doi.org/10.1016/j.proenv.2017.03.153

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