Designing, manufacturing and testing of a micro combined heat and power (micro-chp) system

Transcription

1 Kudistan Jounal of Applied Reseac (KJAR) Pint-ISSN: Electonic-ISSN: kja.spu.edu.iq Volume 2 Issue 3 August 207 DOI: /science Designing, manufactuing and testing of a mico combined eat and poe (mico-chp) system Masood Ebaimi ma.ebaimi@uok.ac.i Mansou Laonian mlaonian@uok.ac.i Sian Faadi s.faadi@uok.ac.i Abstact: In te pesent pape a mico-chp is designed, built and tested based on a 5 kw diesel engine tat is cosen to ecove its ate jacketing and exaust aste enegy and convet it into ate. Te ate may be used as eating souce o domestic ate. Heat ecovey fo te lube oil, adiation, convection, and conduction to ambient is not used since tey all count fo only 3% of te inlet fuel enegy. Te esults include te main caacteistics in te design section, some pictues of te main components, te tempeatue of exaust, ate jacketing and tap ate at diffeent points of te system. In addition te eat ecovey at diffeent engine loads is also given. Te expeiments and esults so tat te oveall efficiency of te CHP system can eac 60% ic means moe tan 30% incease of efficiency en compaing it te case en only electicity as supposed to be poduced by te engine. Keyods: Combined eat and poe, CHP, eat ecovey, enegy efficiency. INTRODUCTION Wile lots of oks and investigations ae devoted to encouage eneable enegy and its elated tecnologies suc as ind tubines, ydo-poe systems, sola panels, biogas eactos, etc, it is essential to pay moe attention to te fossil fuels, its elated tecnologies and possible metods to incease te oveall efficiency of enegy convesion. Statistics and pedictions publised by Enegy Infomation Administation (EIA) [] as poved tat until 202 only 2% of te total old enegy consumption as supplied by eneable enegies, and te emaining 88% as supplied by diffeent fossil fuels. EIA as also pedicted tat te sae of eneable enegies ould become 6% until It means tat at te yea of 2040 still 84% of te old enegy demand ould be supplied by te fossil fuels. Consequently, consistent it tese esults te fossil fuels ould be te main enegy souce fo te uman to te mid-centuy. As a esult, altoug developing te eneable enegies and te elated tecnologies to aise tei sae in te old enegy consumption is impotant; optimizing te existing enegy pocesses and elated tecnologies is essential to educe emission poduction and incease te oveall efficiency of enegy systems. Hence, cleane enegy systems and optimized enegy pocesses in industy ae te foundation of cleane poduction. In addition to te metods intoduced to enance poe geneation efficiency, egula enegy audit, punctual maintenance and coect opeation of otay and stationay enegy convete equipments, and enegy management can assist to keep te temal efficiency of enegy systems as ig as possible [2, 3]. Hoeve, te fuel enegy utilization can be impove fute especially in poe geneation systems suc as gas tubines and intenal combustion engines [4]. Combined eat and poe o CHP, is among te most popula metods tat is still unde investigation to incease fuel enegy utilization in poe geneation units [5]. If te eat ecoveed in te CHP system could be used fo cooling puposes te system is called Combined Cooling Heating and Poe o CCHP ic is also called tigeneation. Te CCHP units ae capable of poducing simultaneous cooling, eating and poe/electicity by using a single enegy souce. Te cooling system is usually an absoption cille, adsoption cille, ejecto cooling system, eat pump, compession cille, o a combination of tese systems. Te CCHP and CHP cycles can be coupled it diffeent eneable enegy systems suc as sola eating, povoltaic cells, and ind tubines as ell. Te main components of a CHP cycle ae te pime move, eat ecovey, and contol system. If te CHP is supposed to become a CCHP te cooling system ill be anote main component of te cycle. Te poe geneato unit (PGU) o pime move of a CHP system may be cosen among diffeent types of fuel cells [6], mico steam o mico gas tubines [7], industial lage size gas tubines [8], industial steam tubines[9], Stiling engines [0], intenal combustion engines [] etc. Deciding about te PGU of a CHP cycle equies gateing and analyzing so muc tecnical, economical, envionmental and social data about te PGUs. Te tecnical data may include te temal efficiency, poe to eat atio, exegy efficiency, etc. Te envionmental caacteistics to be consideed in te decision making ae noise geneation and emission poductions suc as cabon monoxide, cabon dioxide, nitogen oxides, sulfu oxide, soot, paticulates etc. Te economical citeia usually used ae net pesent value, payback peiod, intenal ate of etun, pesent value pemium, etc. Te social o miscellaneous concens also impotant in te decision making step. Examples of tese concens include footpint of equipment, easiness of opeation and maintenance, availability of spae pats, guaantee/ aantee sevices, sanctions ove some tecnologies fo

2 some counties, etc [2-4]. Since some of te caacteistics can be found only qualitatively, geneal statistical metods cannot be used fo decision-making. Teefoe by using decision making metods suc as gey incident metod [2], and fuzzy logic [3] igt pime move ould be cosen. M. Ebaimi et al [4] used gey incident appoac and fuzzy logic simultaneously to coose te igt pime move fo a esidential-cchp system in five diffeent climates of Ian; tey also made a compaison beteen te esults of to algoitms. Tey concluded tat intenal combustions engines ae te best coice fo all climates of Ian. In te pesent pape a mico-chp system is designed, manufactued and tested. Except fo te engine te est of components ee built by te team and assembled to poduce 5 kw of electicity and ecove at least 5 kw of eat at te full load opeation. It means tat in tis case te cycle efficiency ould be doubled. Te aste eat of exaust gases and ate jacketing ae ecoveed as ate tat can be used fo eating pupose o tap. Te esults so significant fuel saving. 2. Modeling and design: Te eat of te mico-chp ic is supposed to be built is a diesel engine it te folloing caacteistics given in Table. Table. Te diesel engine caacteistics Paamete Magnitude Nominal electicity, E (kw) 5 Fuel consumption, F (kg/s) Electical efficiency, (%) 27 Exaust tempeatue, ( ) 540 Exaust flo ate, ( ) 0.0 Wate jacketing, ( ) 0.7 Wate jacketing inlet tempeatue, ( ) 95 Wate jacketing outlet tempeatue, ( ) 03 Te fuel enegy ould be consumed by engine fo poducing electicity and eat losses. Te eat losses appea in te exaust gases, ate jacketing, oil, and ote losses suc as fiction and adiation. Te enegy balance fo te engine can be modeled as belo: F E F e Q mc In ic jacketing, p ex ex T j j oil oil E e () (2) Q ex is te exaust enegy, Q is te ate j Q oil is te oil enegy, and Q is te ote losses suc as fiction and adiation. A eat ecovey system as been designed to ecove te eat losses fom te exaust and ate jacketing. A te eat ecovey system fo te exaust gas is a sell and tube eat excange and a plate eat excange is used to ecove te eat fom te ate jacketing. Te scematic of te mico-chp cycle is pesented in Fig.. Figue. te scematic diagam of te mico-chp and sell and tube (HE) and plate (HE2) eat excanges As it can be seen fom te Fig., te main ate fist entes te plate eat excange at point and eceives eat fom ate jacketing. Tis excange is supposed to decease te ate jacketing tempeatue fom 03 to 95. Ten te peeated ate entes te sell and tube excange at point 2 to be eated by te exaust gases. To avoid condensation and coosion in te gas side of sell and tube excange its tempeatue sould stay above te de point. Consideing te discussions pesented, te tempeatue and mass flo ate at eac point of te cycle can be pedicted by using te fist la of temodynamics. Afte detemining te temodynamics of te cycle, te eat ecovey systems sould be designed and tei eating suface sould be calculated. To acieve te igest possible eat tansfe te and steams in bot te HE and HE2 ae supposed to be counte flo. In tis case te logaitmic mean tempeatue diffeence (LMTD) of te and steams can be calculated as belo: 2 LMTD ln( ) T T 2,out,in 2,in,out (3) To detemine te eat suface aea of eac eat excange te folloing equation sould be used: (4) In ic U is te total eat tansfe coefficient and A is eat suface aea of te excange. Q can be te pat of eat ic is supposed to be tansfeed fom te ate jacketing o exaust gases to te main ate. Te eat tansfe coefficient fo a clean plate o tube aving and steam on eac side (o inside and outside of tube) can be detemined as belo:

3 Plate eat excange Sell and tube eat excange UA A A R t foplate (5) Ak R ln( d o d o ) 2Lk In ic t and L ae te plate tickness and tube lengt, k is te conduction eat tansfe coefficient of tube o plate. In addition and ae te convection eat tansfe coefficient fo te and steams. In te sell and tube eat excange exaust gases flo in te sell side and ate is in te tube side. Futemoe A and A ae te aea ic tat and steams is in contact it. 3. RESULTS: Te mico-chp system is no designed, built and tested. In te folloing some sample esults fo te design, stuctue and test ae supposed to be pesented. 3.. DESIGN RESULTS: Te cycle pesented in Fig. is modeled temodynamically, te enegy balance fo eac component is calculated, te tempeatue and mass flo ate at eac point is detemined. Te esults of enegy balance ae given in table 2. Table 2. Te enegy balance of engine Paamete kw % Fuel enegy ate, F Electicity, E 5 27 Exaust enegy ate Wate jacketing enegy ate Oil and ote enegy ate losses As it can be seen only 27% of te fuel enegy is conveted to electicity, and te est of 73% is asted toug exaust, ate jacketing, lube oil, fiction, adiation and etc. Since te sae of oil and ote enegy losses is small, eat ecovey fo tis pat is not designed. Hoeve te aste eat toug exaust and ate jacketing ae significant it ig quality. Teefoe eat ecovey systems ae designed fo te exaust and ate jacketing. Te tempeatue at eac state point of te Fig. is also given in table 3. As epoted in table 3. Table 3. Te tempeatue and mass flo ate at eac point of te cycle Point Accoding to te esults te ate jacketing inceases te main ate tempeatue fom 20 to 40.6 and ten te exaust inceases it tempeatue to 60. It is convenient since eac of ate jacketing and exausts count fo same sae of fuel enegy tat is about 30%. Te eat ecovey systems fo te jacketing and exaust ae also designed and te esults ae epoted in table 4. Table 4. te main caacteistics of te designed eat ecovey systems Te main caacteistics of te Magnitude plate eat excange (HE) Total eat tansfe coefficient, U 3.30 Heat suface aea, LMTD ( ) Effective aea of eac plate, Pojected aea of eac plate, Total numbe of plates Total eat tansfe coefficient, U Heat suface aea, LMTD ( ) Tube inside diamete(mm) Tube outside diamete(mm) Sell/tube mateial Numbe of tubes Sell inside diamete (mm) Tube lengt (m) Cleaance beteen tubes(mm) Baffle to baffle distance (m) Stainless steel CONSTRUCTION RESULTS: Te data pesented in te pevious section as used to build te eat ecovey systems. Fo example Fig. 2 sos te sell and tube eat excange built fo te exaust eat ecovey.

4 Figue 2. Te sell and tube (up) and plate (don) eat excanges In addition filtes ae constucted fo te engine inlet ai and exaust befoe enteing te sell and tube eat excange. Figue 4. Te mico-chp package 3.3. TEST RESULTS: Te constucted mico-chp is equipped it a monitoing system to monito diffeent impotant paametes of te cycle, including voltage, ampee, tempeatue at diffeent points and ate flo. Fig.5 sos te electicity and eat poduction by te mico-chp cycle at diffeent loads. As it can be seen in all load conditions eat poduction is ige tan te electicity geneation, especially en te engine is opeating belo 50% of its full load o oveloaded. Figue 3. Te filtes used fo te exaust (up) and engine ai inlet (don) In addition to tese components ote components suc as silence, fittings, monitoing system, etc. ee built and te components assembled as son in Fig. 4. Figue 6. Heat and electicity poduced by te mico- CHP 4. CONCLUSIONS: A mico-chp is designed, constucted, and tested to poduce combined eat and poe. Te esults soed tat te mico-chp is able to ecove te eat fom te exaust and ate jacketing and te oveall efficiency is above 60% ic means at least 30% incease in efficiency. Tis system can save significant amount of fuel and educe emission poduction.

5 5. REFERENCE [] Intenational Enegy Outlook (IEO) 206 and EIA, analysis of te impacts of te clean poe plan (May 205). ttp://.eia.gov/tools/faqs/faq.cfm?id=527&t=, Accessed on 20 Septembe 206 [2] A. Hasanbeigi, L. Pice, Industial Enegy Audit Guidebook: Guidelines fo Conducting an Enegy Audit in Industial Facilities, Cina Enegy Goup Enegy Analysis Depatment Envionmental Enegy Tecnologies Division, Octobe 200 [3] S. Das, M. Mukejee, S. Mondal, Detailed Enegy Audit of Temal Poe Plant Equipment, Wold Scientific Nes, 22, 06-27, 205 [4] J. H. Holock, Advanced Gas Tubine cycles, Elsevie Science Ltd, 2003 [5] M. Ebaimi, A. Kesavaz, Combined Cooling, Heating and Poe, Decision-making, Design and Optimization, Elsevie, fist edition, 204 [6] M. Ebaimi, I. Moadpoo, Combined solid oxide fuel cell, mico-gas tubine and Oganic Rankine Cycle fo poe geneation (SOFC-MGT-ORC), Enegy Convesion and Management, 6:20 33, 206 [7] M. Ebaimi, K. Aookos, Integated enegyexegy optimization of a novel mico-cchp Cycle based on MGT-ORC and steam ejecto efigeato, Applied Temal Engineeing, 02: , 206 [8] C. Yang, Z. Huang, Z. Yang, X. Ma, Analytical Off-Design Caacteistics of Gas Tubine-Based CCHP System, Enegy Pocedia, 75: 26 3, 205 [9] M. Amei, A. Bebaaninia, A. A. Tana, Temodynamic Analysis Of A Ti-Geneation System Based On Mico-Gas Tubine Wit A Steam Ejecto Refigeation System, Enegy 35: , 200 [0] X.Q. Kong, R.Z. Wang,,X.H. Huang, Enegy efficiency and economic feasibility of CCHP diven by Stiling engine, Enegy Convesion and Management 45(9-0) , 2004 [] M. Ebaimi, A. Kesavaz, Designing an optimal sola collecto (oientation, type and size) fo a ybid-cchp system in diffeent climates, Enegy and Buildings 08, 0-22, 205 [2] J.-J. Wang, Y.-Y. Jing, C.-F. Zang, X.-T. Zang, G.-H. Si, Integated evaluation of distibuted tiple-geneation systems using impoved gey incidence appoac, Enegy, Vol. 33, NO.9, , 2008 [3] Y.-Y. Jing, H. Bai, J.-J. Wang, A fuzzy multiciteia decision-making model fo CCHP systems diven by diffeent enegy souces, Enegy Policy, Vol. 42, pp , 202 [4] M. Ebaimi, A. Kesavaz, Pime move selection fo a esidential mico-cchp by using to multiciteia decision-making metods, Enegy and Buildings,55, , 202 ACKNOWLEDGMENTS Te autos ould like to acknoledge te Electicity Distibution Company of Kudistan, Ian fo te financial suppot of tis poject.