FEASIBILITY STUDY FOR REPLACEMENT HEATING SYSTEM ON NATURAL GAS WITH PELLET BOILERS AT PRIMARY SCHOOL ST. SAVA IN EAST SARAJEVO

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1 ANNALS of Faculty Engineering Hunedoara International Journal of Engineering Toe XIV [2016] Fascicule [August] ISSN: [print; online] ISSN: [CD-Ro; online] a free-accessultidisciplinarypublication of tefaculty of Engineering Hunedoara 1.Srđan VASKOVIĆ, 2. Petar GVERO,.Vlado MEDAKOVIĆ, 4. Velid HALILOVIĆ FEASIBILITY STUDY FOR REPLACEMENT HEATING SYSTEM ON NATURAL GAS WITH PELLET BOILERS AT PRIMARY SCHOOL ST. SAVA IN EAST SARAJEVO 1,. University of East Sarajevo, Faculty of Mecanical Engineering East Sarajevo, BOSNIA & HERZEGOVINA 2. University of Banja Luka, Faculty of Mecanical Engineering Banja Luka, BOSNIA & HERZEGOVINA 4. University of Sarajevo, Faculty of Forestry Sarajevo, BOSNIA & HERZEGOVINA ABSTRACT: Tis study describes te possibility of installation of pellet boilers for te production of teral energy for eating in te priary scool Sveti Sava in Lukavica. Existing eating syste wit natural gas turned out to be very expensive wit ig costs in ters of consuption of natural gas on annual level but also due to te ig price of natural gas. Alternative possibility of eating preises witin te scool is seen in te installation of boilers tat use wood pellets as an energy source. Above all, wood pellet represents an environentally clean fuel in ters of CO 2 eissions, but also because of te availability of resource fro nearby factories tat produce pellets, it can be used as a doestic fuel. In tis way, te story of sustainable counity developent is encouraged, as well as te flow of capital witin te counity is closed. Keywords: Pellet, investent, econoy, ecology, benefit, eat boiler 1. INTRODUCTION Priary scool St. Sava currently as two gas boilers wit te power of 1=260kW and 2=100kW. Te boiler wit ore power is used for eating te area intended for classroos, offices, toilets, wile te boiler wit less power is used for eating te gy. Te approxiate surface area of te scool tat is eated is A1= and te area of te gy is A2= Tus, te total approxiate area tat is eated is about A= Te purpose of tis study is to sow tat te alternative installation of wood pellet boilers and production of eating energy in tis way a) b) Figure 1. (a) Priary scool St. Sava Picture and (b) Gy will provide significant savings in coparison to eating syste wit natural gas. Figure 1 sows: (a) Priary scool St. Sava Picture and (b) Gy. 2. BUSINESS IDEA 2.1. General In te priary scool Sveti Sava it is planned for gas boilers to be replaced wit new pellet boilers. Te plan is to provide a boiler wit capacity of 00kW for te ain scool building, wic is related to classroos and office space area of , due to te tendency to expand te space. For te building tat refers to te gy wit a surface of (because of te eigt 255 Fascicule

2 ANNALS of Faculty Engineering Hunedoara International Journal of Engineering of te all of ore tan 10) it is necessary to provide a boiler wit capacity of 100kW. Expectations related to te replaceent of fossil fuels (natural gas) wit bio-fuels (pellets), refer to te reduction of dependence on fossil fuels fro suppliers, reduction in te fuel costs, as well as reducing of noxious eissions of carbon dioxide CO2. All of tese benefits associated togeter, give tis scool a positive iage of raising awareness to te uan environent. Particular epasis is on te fact tat te scool is concerned as educational institution wic would provide an exaple to students and everyone else about te possibility of using renewable energy sources and protection of te environent by using of clean ecological fuel Fuel Wit te elp of lignin contained in te wood, by increasing of pressure and teperature during te pressing process, it is excreted in te outer layers and tus leads to foration of wood bark tat protects te briquette and pellet fro ecanical daage and oisture. Te diaeter of pellet is usually about 8, and its lengt is about Te oisture content in wood pellet is very low, about 7-10%. Te rest of te as after cobustion of pellet is very low, about 0.5%. Te density of pellet is about kg/. Te calorific value of pellet is fro 4.7 to 5 kw/kg (16.9 to 18MJ/kg). A ig quality pellet wit no adixtures of bark usually as a calorific value of 5kW. Te energy content of te bulk cubic eter of pellet is about kW/. One tone of pellets takes up about 1,5 of te storage [1]. 2.. Custoers Te priary scool St. Sava is te ultiate beneficiary of eat produced wit te elp of te new built-in pellet boiler. Tis business plan elps te scool anageent to look into te benefits and investent feasibility of tis project of alternative installation of pellet boilers Benefit for scool and environent Existing boilers tat operate using natural gas ave a total installed capacity of approxiately 60kW. Boiler No. 1 wit capacity of n =260kW as gas consuption at axiu load of: n q = 29,8 H = (1) d Te actual consuption of gas due to te correction of te eating value is: q1s = 1, 4 (2) Boiler No. 2 wit capacity of n =100kW as gas consuption at axiu load of: n q = = 12,5 Hd () Te actual consuption of Boiler No.2 due to te correction of te flow is: q2s = 1, 2 (4) were tey are te following: η k =0,88 te efficiency of gas boiler, H d =5696kJ/ lower eating value of natural gas, design value[2]. However, natural gas boilers fired wit total power of P=60kW during te eating season ave different levels of load and never operate at full load (during te stationary operation ode and during te entire eating season). Te following table gives an overview of te ontly bills for gas during te last tree years. Table 1. Costs for gas consued during te past tree years, for eating of te scool St. Sava [] Year 2011 Year 2012 Year 201 January.97,59 January 5.474,42 January 5.225,21 February 5.08,80 February 6.19,22 February 4.55,97 Marc.140,1 Marc.524,04 Marc.79,06 April 0,00 April 2.178,44 April 1.299,85 October 2.271,59 October 1.99,58 October 2.000,00 Noveber 5.19,66 Noveber 2.958,95 Noveber.000,00 Deceber 5.64,25 Deceber 5.855,69 Deceber 5.65,25 Total: ,2 Total: , Total: 25.09, Average costs of gas during te last tree eating seasons Fascicule

3 ISSN: [print]; ISSN: [online] Fro te table 1 it is clear to notice tat during te past tree years te igest peak of bills for consued gas occurred in February, in At te sae tie fro tis table it can be concluded tat te biggest bills of gas are consued in tree critical winter onts (Deceber, January and February). Te sallest bills for te consued gas appeared in April. Tese seven onts wic were observed and given during te eating season, are relevant to te overall budget of consued gas. Te priary scool St. Sava works in two sifts, so te daily work of boilers includes a iniu of 12 ours. For calculation of te average level of te load on te gas boiler, during te eating season, it can be taken te average bill for gas of Te average ontly bill for gas during te period of 7 onts is: = 722 (5) 7 Te average consuption of gas (in arks) by an our of work of boilers is: 722 = 1,5 (6) 2 12 Te average gas consuption is approxiately: 1,5 = 1,5 1 (7) Te average load of gas boilers during te eating season is: qs Hd 1,5 0, s = = = 118 kw. (8) On te basis of calculating te average load of gas boilers, we are going to calculate te consuption of pellet during te aforeentioned eating season. Te average load of gas boilers is 120/60=0.. We will start te calculation under te assuption of ediu load of pellet boilers of 0. on te basis of loads of old boilers. Tus, te average load of te pellet boilers is 400 x 0. = 120 kw (it represents te suarized average load of bot of te boilers) during te entioned period of te production of teral energy s kg qp = = 600 = 26 kj (9) Hdp 0, kg and were is Hdp -lower eating pellet s value If we consider te eating season of 7 onts, 2 working days and 12 ours of work per day, we get te total consuption of pellet: kg ton Lp = = godini = godini. (10) If we know tat te price of pellet is 250 per one tone, and ten we ave tat te cost price of pellet for te wole season is: C p = LP 250 = (11) ton If you copare it wit te bill for gas of Table 2. Ratios of carbon dioxide eissions , significant savings are of different fuels[5] evident, wic are: U1=1.02 at Fuel Eission in kg CO 2 /GJ te annual level. As for te reduction of Bioass 109,6 eissions in ters of carbon dioxide CO2 peat 106 Te eission of CO2 Stone coal 101,2 is considered to be Dark coal 97,09 zero during te cobustion of wood Lignite 96,4 pellet. Tis all is applicable for sustainable Diesel 77,4 forest anageent. Te aount of Crude oil 74,1 carbon dioxide tat is eitted during te kerosene 7, cobustion of pellets is approxiately gasoline 71,5 equal to te sae aount of CO2 Liquefied petroleu gas 6,1 incorporated into te structure of wood natural gas 56,1 bioass during te process of potosyntesis. Total edian value of te 257 Fascicule

4 ANNALS of Faculty Engineering Hunedoara International Journal of Engineering gas consued during te eating season is V= (of standard cubic eters at teperature of 15 0 C and pressure of 1.01 bar). Te botto eating value of Russian natural gas is 4 MJ/, correction value of teral power [4]. Te following table illustrates te carbon dioxide eissions for certain fuels. Te eission of CO2 for natural gas per GJ of energy fro te caloric power of gas is e1 = 56.1 kgco2/gj. Te quantity of carbon dioxide eitted expressed in kg during te eating season wen natural gas is used as te energy source in te previously entioned scool is: CO2 = 49,69 tons. It is evident tat tere is te reduction of arful CO2 eission into te atospere wen using wood pellets as fuel. Tere are tree pellet plants at te radius of 0 k. In order to ensure te security of supply it is possible to enter into te contract on an annual basis wit te anufacturers. Two pellet boilers total power of kw along wit te calculated sall silos for te storage of wood pellets for seven days. It practically eans tat it is necessary to store approxiately 26 x 12 x 7 = tons of pellet and regarding te fact tat te tone of pellets takes about 1.5 it would ean tat bot boilers would need silos for seven days period of x 1.5 = 276 approxiately.. Te first silo of 2.2 will be provided for te bigger boiler and te second one of 1.1 for te saller. Te volue of a silo ay vary depending on te anufacturer of te equipent and its tecnical solutions. For storage of te total fuel (pellets) required for eating during one eating season, it is necessary to provide x 12 x 2 x 7 x 1.5 = 75 or approxiately te volue space of 6 x 6.5 x 2 = THE SITUATION ON THE MARKET WITH PELLETS AND OTHER ENERGY SOURCES Te arket of pellets and bioenergy sources are still at te pase of developent. Tere are no significant consuers of tese sources of energy near above-entioned scool. Te pellet plant Eu-pal d.o.o., is at a distance of approxiately 0 k. Te construction of gas pipeline Sout Strea will not significantly affect te reduction of gas prices priarily because its custoers will be te ultiate beneficiaries of tis syste. On te oter and, reserves of fossil fuels are very liited and a significant increase in prices of fossil fuel are to be expected in te future tie. 4. FINANCIAL INDICATORS OF INVESTMENT Te following table of calculations indicates te justification of investing in te replaceent of pellet boilers in te above entioned facility. Te investent expenses, table 4, refer to te costs of boilers and installation of syste as well as te construction of te pellet storage. Data and boiler prices are taken over fro te official web site of te anufacturer [6]. Table 4. Te investent expenses [6] INVESTMENT EXPENSES 258 Fascicule In taxes included Boiler No.1 of power 00 kw wit outlet fan 2.166,00 Boiler No.2 of power 100 kw wit outlet fan ,59 Additional equipent for bot boilers: 1. Wireless terostat prograer (wit 7 days scedule) 2. Telepone and ode ( boiler on and off by telepone, landline connection needed). Boiler anaging by GSM control 4. As outlet container wit engine 5. Big boiler silo of 100 KW and ore Table. Te justification of investing in te replaceent of pellet boilers in te above entioned facility EXPENSES Expenses in fuel (old syste) Expenses of pellet purcasing on te annual basis ( in te suer period) Expenses of transport, operating and aintenance expenses Total cost of pellet eating syste Annual savings in regard to previous syste wic uses natural gas x( ) = Pellet storage construction, installation, preparation of a study and oter costs Lectures on Green package and proo aterial for worksops eld by.000 experts and teacers TOTAL VALUE OF INVESTMENT about INVESTMENT RETURN FOR ITS OWN FUNDING /10.02 = 5.6 year In case of donation, te boiler would bring te estiated annual savings of 1002 in te first year of exploitation. Te working life of boiler is up to 15 to 20 years.

5 ISSN: [print]; ISSN: [online] 5. CONCLUSION Tis exaple could also be a good prooter of using wooden bioass as a renewable energy source, but at te sae tie, it represents a unique educational exaple to raise awareness on environental protection. On financial side, we ave in tis exaple wit relatively sort payback period of investent. Terefore, te best way is to start wit te prootion of renewable energy sources fro pupils in priary scools and enable te to raise awareness and personal knowledge of tis for of pure energy on te exaple of teir own scool. Liited knowledge about te pellet as energy source could be a disadvantage in te process of pellet supply. It is necessary to find a secure supplier wo would provide pellet of ig quality witout bark and ig eating capacity as defined by te calculations. Due to te sall capacity of pellet boilers and sall deand during eating season, te scool could not possibly be te significant syste wic would cause any great deand for tis fuel. However, in te near future we sould expect greater deand for pellet as a fuel. We ust also keep in ind tat te cost of fossil fuel is very variable and its growt is to be expected. On te oter and, te existing gas boilers will reain operative and tus ensure tat te scool as te possibility of alternative gas eating. Tis is certainly an additional safety factor for te existing facility in case of any significant turbulence in te prices and supply of pellets. References [1] Wood pellet in Finland, tecnology, econoy and arket, OPET report 5, Tecnical Researc Centre of Finland, JYVÄSKYLÄ, [2] Taken over fro te tecnical docuentation of te project- te part wic refers to installation of boilers for eating on te natural gas [] Taken over fro Priary scool St. Sava, accounting service [4] ttp:// [5] ttp:// nja.pdf [6] ttp:// ANNALS of Faculty Engineering Hunedoara International Journal of Engineering copyrigt UNIVERSITY POLITEHNICA TIMISOARA, FACULTY OF ENGINEERING HUNEDOARA, 5, REVOLUTIEI, 1128, HUNEDOARA, ROMANIA ttp://annals.fi.upt.ro 259 Fascicule