THE CONSUMPTION OF FINAL ENERGY FOR HEATING EDUCATIONAL FACILITIES LOCATED IN RURAL AREAS

Tomsz SZUL Uniwersytet Rolniczy im. Hugon Kołłątj w Krkowie Ktedr Energetyki i Automtyzcji Procesów Rolniczych ul. Blick 116B, 30-149 Krków, Polnd e-mil: t.szul@ur.krkow.pl THE CONSUMPTION OF FINAL ENERGY FOR HEATING EDUCATIONAL FACILITIES LOCATED IN RURAL AREAS Summry The disserttion includes n nlysis of the consumption of finl energy for heting 73 eductionl fcilities situted in rurl res of the Krków povit. Clculting the unit rte for finl energy demnd EK w kwh/m 2 ws crried out pplying two methods, ccording to the methodology of estimting the energetic performnce of buildings. The vlue of the unit rte for the finl energy demnd EK depends on the ssumed clcultion method nd equls (verge vlue for the nlyzed group of fcilities), respectively: 171 kwh/m 2 for the method bsed on the ctully used energy nd 203 kwh/m 2 for the clcultion method bsed on the stndrd mnner of use. Mjority (70%) of the eductionl fcilities situted in rurl res of the Krków povit re effective in the field of using het energy (unit use of the finl energy bove 240 kwh/m 2 ); 30% of these cn be described s energy-efficient (EK<140 kwh/m 2 ). 7% of the eductionl fcilities (EK >341 kwh/m 2 ) require crrying out thermo-moderniztion procedures. Clcultion of the vlue of the EP rte using the two methods llowed to compre the results for which the verge reltive error of the MAPE estimte for the nlyzed eductionl fcilities is 17% (the results obtined ccording to the method bsed on the ctully used energy). Therefore, when estimting the consumption of the finl energy ccording to the clcultion method bsed on the stndrd mnner of use, the vlues of the rtes re significntly over-specified. Key words: consumption of energy in eductionl fcilities, finl energy, energy performnce, degree dys of heting seson ZUŻYCIE ENERGII KOŃCOWEJ NA OGRZEWANIE OBIEKTÓW OŚWIATOWYCH ZLOKALIZOWANYCH NA OBSZARACH WIEJSKICH Streszczenie W prcy dokonno nlizy zużyci energii końcowej n ogrzewnie 73 obiektów oświtowych zloklizownych n obszrch wiejskich powitu krkowskiego. Obliczeni jednostkowego wskźnik zpotrzebowni n energię końcową EK w kwh/m 2 wykonno dwom metodmi zgodnie z metodologią szcowni chrkterystyki energetycznej budynków. Wrtość jednostkowego wskźnik zpotrzebowni n energię końcową EK, zleżn jest od przyjętej metody obliczeń i wynosi (wrtość przeciętn dl nlizownej grupy obiektów) odpowiednio 171 kwh/m 2 dl metody oprtej n fktycznie zużytej energii i 203 kwh/m 2 dl metody obliczeniowej oprtej n stndrdowym sposobie użytkowni. Obiekty oświtowe zloklizowne n obszrch wiejskich powitu krkowskiego w większości (70%) są efektywne w wykorzystniu energii cieplnej (jednostkowe zużycie energii końcowej poniżej 240 kwh/m 2 ), trzydzieści procent z nich możn określić jko energooszczędne (EK<140 kwh/m 2 ). Siedem procent obiektów oświtowych (EK >341 kwh/m 2 ) wymg zbiegów termmodernizcyjnych. Obliczenie wrtości wskźnik EP dwom metodmi pozwoliło n porównnie otrzymnych wyników, w tym celu wyznczono średni błąd względny oszcowni MAPE (przyjmując jko poziom odniesieni wyniki uzyskne według metody oprtej n fktycznie zużytej energii), który dl nlizownych obiektów oświtowych wynosi 17%. W związku z powyższym, szcując zużycie energii końcowej według metody obliczeniowej oprtej n stndrdowym sposobie użytkowni w sposób znczący zwyż się wrtości wskźników. Słow kluczowe: zużycie energii w obiektch oświtowych, energi końcow, chrkterystyk energetyczn, stopniodni sezonu grzewczego 1. Introduction The ct of 15 April 2011 on energy performnce implemented the provisions of the 2006/32/EC on the effectiveness of the finl consumption of energy nd energy services [17]. It points t the leding role of the public sector fcilities in the re of economicl energy mngement. According to the provisions of the ct, citizens should be informed of the ctions tken s prt of plying this exemplry role. The ctions tken by the public sector units, including municiplities nd povits, re primrily focused on incresing energetic stndrds of eductionl fcilities, mong others, crrying out their thermo-moderniztion. Acting ccording to the provisions of the 2010/31/EU Directive on energetic performnce of buildings [7], introducing the obligtion of creting energy performnce certifictes for ech new building for which, due to rebuilding or renovtion (crried out thermo-moderniztion) their energy performnce chnged. In 2014 the Act on buildings energy performnce [18] ws introduced; the Act specified: - The rules for prepring energy performnce certifictes; - The rules for the heting nd ir conditioning systems control in the buildings; - The rules for keeping the centrl register of the energy performnce of buildings; - The method of developing stte ction pln iming t incresing the number of low energy consumption buildings. 171

Item 15 of the Act sttes tht: 1) The minister competent for the construction, locl plnning, nd lnd development nd housing shll specify, by ordinnce, the methodology of setting the energy performnce of building or prt of building, the method of prepring of energy performnce certifictes nd their models. 2) The minister competent for the construction, locl plnning, lnd development nd housing, when issuing the ordinnce mentioned in prgrph 1, shll include the following: technicl prmeters of the building structure or prt of the building, types of technicl systems in the building or prt of the building, methodology of setting the energy performnce bsed on the stndrd mnner of use of the building or prt of the building, methodology of setting the energy performnce bsed on the ctully used mount of energy. Pursunt to this Act, the Minister of Infrstructure nd Development issued new ordinnce on the methodology of clculting the energetic performnce of buildings nd residentil units or prt of building constituting n independent technicl-service entity, s well s the method of prepring the models of energy performnce certifictes (hereinfter referred to s the methodology), where two methods of setting energy performnce were introduced, i.e. the method bsed on the stndrd mnner of use nd climtic dt ssumed from the nerest wether sttion dtbse, nd the other one, bsed on the quntity of the ctully used energy [13]. Het demnd is clculted ssuming tht the normtive conditions of use, i.e. the tempertures in the premises set in the ordinnce on the technicl conditions tht the buildings nd their loction should meet [15]; the most fvorble outdoor tempertures set for given climte zone in the PN-82/B-02403 [11] norm, verge monthly outdoor tempertures nd the solr rdition rtes for seprte months - ccording to the multi-nnul verge dt specified for the nerest wether sttion; the size of the strem of ventiltion ir which reltes to the usble re of the building nd is set by the indictor vlue method. Clcultions concerning energy demnd in n eductionl fcility include, mong others: - the energy used for heting nd ventiltion, - the energy used for heting the wter, where lso in this cse the indictor vlue method clcultions were employed pplied to the usble re of the building. Energy demnd is subsequently clculted for: usble energy (used directly), finl energy (supplied to the building nd including the losses resulting from the energy conversion efficiency of the instlltion systems) nd primry energy (including the losses occurring during genertion nd energy supply s well s the type of energy crrier). Evlution of the size of demnd for the usble energy for heting, ventiltion nd cooling is performed by pplying the monthly blnce sheet method ccording to the PN-EN ISO 13790:2008 norm [12]. In the cse of the use-bsed method, yerly demnd for the finl energy supplied to the building, for the heting system nd the usble wter heting system re set bsed on the documents confirming the ctul use of the district het or nturl gs for the needs for heting nd usble wter heting. The Q W+Hk, vlue in the kwh/yer units is the verge of the district het or nturl gs consumption of the lst 3 yers before issuing the energy performnce certificte. Despite the methodology does not ssume reclcultion (correction) these clcultions for the conditions of stndrd seson, the person crrying out the clcultions of the energy performnce should lso perform these clcultions in order to be objectively ble to show the energy qulity of the building, due to the provisions of the 2006/32/EC Directive [8] on the effectiveness of the finl energy consumption. This person is obliged by legisltion tht clerly suggest tht for the ske of objectivity in estimting energy consumption - the results of ctul energy consumption in the previous heting sesons should be compred with the consumption clcultion, ssuming wether conditions previling in the compred periods. Bering in mind the provisions contined in the quoted legl cts nd the fct tht there is scrcity of studies providing informtion on het consumption by eductionl institutions, which in rurl nd semi-urbn res re the dominnt prt of the buildings of the public sector, the im of the study ws to determine the energy performnce of eductionl buildings (locted in the rurl district of the Krków povit), expressed by the individul indictor of demnd for finl energy EK kwh/m 2. The clcultions were crried out by two methods of determining energy performnce, i.e.: bsed on the ctul mount of energy consumed (djusted to the conditions of the stndrd seson), nd bsed on stndrd method of use of the building, ccording to the Ordinnce of the Minister of Infrstructure of 2 July 2014 on the methodology of preprtion energy performnce certifictes [13]. This llowed objective comprison of the obtined results. 2. Study subjects nd methodology Bsed on dt from the Informtion Center of Eduction [2] the following informtion ws obtined: s of 2015 in the rurl res of the Krków povit there were 267 eductionl institutions locted in 194 buildings (79 kindergrtens, 125 primry schools, 44 junior high schools nd 19 secondry schools) ttended by pproximtely 29 thousnd students, pproximtely 2 thousnd techers were employed. On this bsis the minimum smple number of the buildings ws specified; it is 64 fcilities (for confidence level α = 0.95 nd mximum error of 10%), where the clcultions of finl energy consumption for heting were performed. The study ws conducted in 73 eductionl institutions locted in 17 rurl nd urbn-rurl res of the povit of Krków. The nlyzed fcilities in recent yers, for the most prt (53 buildings) hve undergone the process of thermo-moderniztion bsed on therml insultion of the building envelope (including the replcement of windows) nd the moderniztion of their heting systems. All of the buildings re heted with boilers with gs burners. The totl re of the fcilities nlyzed is 87 thousnd m 2 ; they re ttended by pproximtely 8.3 thousnd students. A chrcteristic feture of eductionl fcilities in rurl res is wide vrition in their res nd in the number of students. The res of the nlyzed fcilities rnge from 150 m 2 to ppropritely 3500 m 2 nd from 36 to 570 students lerning there. Dt concerning the prtition mterils, surfce res nd volumes, s well s the dt on the surfce of the prtitions (wlls, ceilings, windows nd doors) subject to het loss were obtined in the nlyzed fcilities. In ddition, the informtion on the mount of gs consumed for heting the buildings ws obtined. The dt include heting sesons of 172

the yers 2013, 2014 nd 2015. Clcultions of the finl energy, EK, demnd were crried out in ccordnce with the methodology for clculting energy performnce of building or nd residentil unit or prt of the building constituting n independent technicl-service entity, using the use-bsed method (bsed on the ctul energy consumption) nd the clcultion method bsed on the stndrd method of use (hereinfter referred to s the clcultion method) [13]. In the method, bsed on the ctully consumed energy, the dt on the het of the combusted gs supplied to the buildings (used to clculte the finl energy consumption) re ssumed on the bsis of informtion for the Settlement Are of the Het of Combustion (ORCS) in Polsk Spółk Gzownictw Sp. o.o. for the re of settlement, including the municiplity of Zbierzów, nd for the nlyzed yers, it mounts to n verge of 11.09 kwh/m 3 which gives the clorific vlue of the gs t the level of 10.11 kwh /m 3 [10]. Although the methodology [13] does not ssume reclcultion (correction) the ctul energy consumption for heting nd ventiltion conditions of the stndrd seson, such clcultions were crried out here using the following formul: Q K, H 3 Sd( t Sd b t ) i Q K, H i 1 3 i1 b 0, (1) Q K,H - the finl energy demnd for the heting seson stndrd, [kwh], Sd(t b) 0 the number of degree dys in stndrd heting seson, [ o Cd], Sd(t b) 0 the number of degree dys for the i of this yer, [ o Cd], Q K,H i finl energy consumption for heting in mesurement period for the i of this yer [kwh]. Climtic dt on the bsis of which the clcultions were conducted, were tken from the dtbse of the Krków-Blice wether sttion for the stndrd yer [9] nd for the yers 2013, 2014 nd 2015 [19]. These were used to determine the degree dys of the heting seson Sd (15 C) in the stndrd yer [5] nd for the i of this yer, clculted bsed on the Hitchin formul [3]: 9 tb tśr Sd( tb) Sd( tb) m k t t L b śr m i1 1 exp, (2) Sd(t b )0 the number of degree dys in heting seson, [ o Cd], Sd(t b) m the number of dy degree for ech month of the heting seson, [ o CD], ccording to the methodology [] the heting seson lsts nine months, i.e. from Jnury to My nd from September to December, t b ssumed bse temperture, [15 o C] [6], t śr verge monthly temperture, [ o C], k constnt for Krków = 0,821 [4], L m numbers of dys in month [d]. The clculted number of degree dys in the stndrd heting seson Sd(t b) 0 is 3615,9 [ o Cd], nd in the yers of 2013, 2014, nd 2015 it is, respectively, Sd(t b) i: 2789,1; 2766,9; 2542,6 [ o Cd] which gives the verge of the 3 yers on the level of 2699,5 [ o Cd]. Compring the results obtined, it cn be concluded tht the number of degree dys of the stndrd seson is higher by pproximtely 34% compred to the number of degree dys in the mesuring period (2013-2015). 3. Study results nd nlysis The results of the clcultion of the nnul energy demnd expressed by the indictor EK kwh/m 2, clculted by using the method bsed on the ctul energy consumed EK rz nd the clcultion method EK t re summrized in Fig. 1. The nlyzed group of eductionl fcilities shows the finl energy consumption expressed by the unit demnd indictor for finl energy EK rnging from pproximtely 60 to 450 kwh/m 2 (in one building the recorded energy level ws 600-650 kwh/m 2 ). Source own work / Źródło: oprcownie włsne Fig. 1. The indictor unit consumption of finl energy EK in the group of buildings nlyzed ws set pplying the use-bsed method nd the method bsed on the stndrd use Rys. 1. Zużycie energii końcowej w nlizownych budynkch wyznczone metodą eksplotcyjną orz obliczeniową 173

The verge vlue of this indictor depends on the pplied clcultion method nd mounts to 171 kwh/m 2 for the method bsed on the ctul energy consumed nd to 203 kwh/m 2 for the clcultion method. According to the dt vilble in the literture [1], the vlue of the unit indictor of the demnd for finl energy EK (clculted ccording to [14]) for this type of buildings in the province of Młopolsk is 185 kwh/m 2, nd therefore it cn be concluded tht the results obtined for the nlyzed buildings do not devite significntly from this vlue (they vry by pproximtely 8%). The confidence intervl for the methods compred mounts respectively to 156 to 185 kwh/m 2 (use-bsed method) nd to 187-219 kwh/m 2 (clcultion method). Fig. 2 shows the structure of the building in terms of the mount of energy consumption. Source own work / Źródło: oprcownie włsne Fig. 2. The structure of eductionl buildings in terms of the vlue of the EK indictor Rys. 2. Struktur budynków oświtowych ze względu n wrtość wskźnik EK Anlyzing the structure of eductionl buildings in terms of the mount of het energy, it cn be stted tht for the most prt these buildings mke n effective use of het energy (unit finl energy consumption below 240 kwh / m 2 ), nd tht 30% of them cn be described s energyefficient (EK<140 kwh/m 2 ). 7% of the eductionl fcilities (EK >341 kwh/m 2 ) require crrying out thermomoderniztion procedures. To compre the method bsed on the ctul energy used to the clcultion method, the verge reltive error of estimte ws determined (MAPE), ccording to formul 3. 1 MAPE n n t1 d d d p 100 [%], (3) d the indictor of the unit demnd for finl energy determined by the use-bsed method, [kwh/m 2 ], d the indictor of the unit demnd for finl energy determined by the clcultion method, [kwh/m 2 ], n the number of the eductionl building for which the clcultions were mde. The verge reltive error of estimte (MAPE) for the nlyzed group of 73 eductionl fcilities is 17%. The reltive error between the verge vlues of EK indictor (tking s reference level - s in the clcultion of MAPE - the index obtined by the use-bsed method), ws lso clculted; in this cse the error vlue is - 19%, nd therefore the right choice of the method of clcultion is not without significnce - lower scores of the EK indictor re obtined when using the method bsed on the ctul energy consumed. Similr conclusions (bsed on clcultions mde for residentil detched house) were obtined in study [16] where the reltive estimte error between use-bsed method nd the clcultion method ws lso 17%. 4. Conclusions The nlysis of energy consumption for heting eductionl fcilities in the rurl res in the povit of Krków crried out in this study llowed us to estimte the size of the unit indictor of demnd for finl energy EK kwh /m 2, whose verge vlue is dependent on the ssumed method of clcultion nd mounts, respectively, to 171 kwh / m 2 for the method bsed on the ctully consumed energy nd 203 kwh / m 2 for the clcultion method bsed on stndrd method of use. The confidence intervl for the finl energy EK unit indictor mounts respectively to 156 to 185 kwh/m 2 (usebsed method) nd 187-219 kwh/m 2 (clcultion method). For the nlyzed re of the Krków povit, the number of degree dys of the stndrd seson (which constitutes the point of reference) is higher by pproximtely 34% compred to the number of degree dys in the mesuring period (2013-2015). Thus, even though the provisions of the methodology for estimting energy do not ssume reclcultion (correction) of the clcultions obtined by the usebsed method of the stndrd seson conditions, the results obtined should be corrected nd the obtined results nd referred to the stndrd conditions of the seson, in order to be objectively ble to specify the qulity of energy performnce of buildings. Mjority (70%) of the Eductionl fcilities situted in rurl res of the Krków povit re effective in the field of using het energy (unit use of the finl energy bove 240 kwh/m 2 ); 30% of these cn be described s energy-efficient (EK<140 kwh/m 2 ). 7% of the eductionl fcilities (EK >341 kwh/m 2 ) require crrying out thermo-moderniztion procedures. Drwing up the energy performnce of buildings should be crried out, s fr is it is possible, by pplying the usebsed method on the bsis of the ctul energy consumed. This is due to the fct tht the verge reltive error of estimte (MAPE) for the nlyzed eductionl fcilities is 17%, while the reltive error between the verge vlues of the index is -19%. Therefore, when estimting the use of the finl energy ccording to the clcultion method bsed on the stndrd mnner of use, the vlues of the rtes re significntly over-specified. 5. References [1] Builddesk 2012. Jkość energetyczn budynków w Polsce. http://www.builddesk.pl/files/builddesk/consultncy/pl%20 BD%20Anlytics/2010-12-stn-energetyczny-budynkow.pdf. [2] Centrum Informtycznego Edukcji http://www.cie.men.gov.pl/index.php/sio-wykz-szkol-iplcowek/26-wykz-wg-wojewodztw.html. [3] Degree-dys: theory nd ppliction TM41. 2006. The Chrtered Institution of Building Services Engineers 222 Blhm High Rod, London SW129BS. [4] Dopke J.: Liczb stopniodni grzni dl dwudziestu sześciu mist Polski w 2010 r. www.cire.pl 07.11.2011. 174

[5] Dopke J. Zużycie energii do ogrzewni budynków w trzydziestu trzech mistch Polski w 2013 r. Ciepłownictwo, Ogrzewnictwo, Wentylcj. Wydwnictwo SIGMA-NOT, 2014. Tom 45, 5, 171-178. [6] Dopke J.: Wyzncznie tempertury bzowej budynku, www.ogrzewnictwo.pl 24.09.2012 r. [7] Dyrektyw 2010/31/UE Prlmentu Europejskiego i Rdy z dni 19 mj 2010 r. w sprwie chrkterystyki energetycznej budynków. [8] Dyrektyw 2006/32/WE Prlmentu Europejskiego i Rdy z dni 5 kwietni 2006 r. w sprwie efektywności końcowego wykorzystni energii i usług energetycznych orz uchyljąc dyrektywę Rdy 93/76/EWG. [9] Ministerstwo Infrstruktury i Rozwoju. Typowe lt meteorologiczne i sttystyczne dne klimtyczne dl obszru Polski do obliczeń energetycznych budynków; http://www.mir.gov.pl/budownictwo/rynek_budowlny_i_tec hnik/efektywnosc_energetyczn_budynkow/typowe _lt_meteorologiczne/strony/strt.spx. [10] Obszry Rozliczeniowe Ciepł Splni nr ORCS 040027 (oddził PSG - Trnow, gmin Zbierzów) http://www.psgz.pl/dlklient/18869/21361 dostęp 18.05.2016. [11] PN-82/B-02403 Tempertury zewnętrzne obliczeniowe. [12] PN-EN ISO 13790:2009 Energetyczne włściwości użytkowe budynków - Oblicznie zużyci energii n potrzeby ogrzewni i chłodzeni. [13] Rozporządzenie Ministr Infrstruktury i Rozwoju z dni 2 lipc 2014 r. w sprwie metodologii obliczni chrkterystyki energetycznej budynku stnowiącej smodzielną cłość techniczno-użytkow orz sposobu sporządzni i wzorów świdectw ich chrkterystyki energetycznej. Dz. U. 2014 poz. 888. [14] Rozporządzenie Ministr Infrstruktury z dni 6 listopd 2008 r. w sprwie metodologii obliczni chrkterystyki energetycznej budynku stnowiącej smodzielną cłość techniczno-użytkow orz sposobu sporządzni i wzorów świdectw ich chrkterystyki energetycznej. Dz.U. 2008 nr 201 poz. 1240. [15] Rozporządzenie Ministr Trnsportu, Budownictw i Gospodrki Morskiej z dni 5 lipc 2013 r. zmienijące rozporządzenie w sprwie wrunków technicznych, jkim powinny odpowidć budynki i ich usytuownie. Dz.U. 2013 poz. 926, [16] Szul T. Comprison of Methods in the Definition of Home Energy Chrcteristics in the Context of the Europen Union Directives, Brometr Regionlny. Anlizy i Prognozy, 2015, 3(41), 73-80. [17] Ustw z dni 15 kwietni 2011 roku o efektywności energetycznej. Dz.U. 2011 nr 94. poz. 551. [18] Ustw z dni 29 sierpni 2014 r. o chrkterystyce energetycznej budynków. Dz.U. 2014 poz.1200. [19] Wether History for Krków http://www.wunderground. [20] com/history/irport/epkk/2015/2/14/customhistory.html. This Reserch ws finnced by the Ministry of Science nd Higher Eduction of the Republic of Polnd. 175