Modelling and optimization of multi-energy source building systems in the design concept phase

Transcription

1 rocdgs of Clima 2007 WllBg Indoors Modllg and opimizaion of muli-nrgy sourc buildg sysms h dsign concp phas Vcnzo Corrado, Enrico Fabrizio and Marco Filippi Diparimno di Enrgica (DENER), olicnico di Toro, Toro, Ialy Corrspondg mail: nrico.fabrizio@polio.i SUMMARY A growg rs has bn addrssd o muli-nrgy sysms buildgs ha volv h graion of diffrn nrgy sourcs o covr h hrmal and lcrical loads of h buildg. A modllg approach o muli-nrgy sysms buildgs basd on h concp of hybrid nrgy hub is prsnd. Th modl has bn cusomisd o b usd h concp phas of h buildg dsign, ihr as a sysm simulaion ool or as a sysm dsign opimizaion ool. Givn h prics of chnologis and of nrgy-wars, undr a cra s of consras i is possibl o drm h configuraion ha mimiss h capial cos, h primary nrgy consumpion or h lif-cycl cos. This approach allows avoidg a burdnsom simulaion and rankg of a s of diffrn sysms. In h nd, an applicaion on a cas sudy is providd. INTRODUCTION Th nrgy sysm of a buildg is h complx of buildg plans ha ransform primary (chmical, hrmal, solar, wd) and scondary (lcriciy, hydrogn) nrgy-wars o nrgy usd o covr h buildg nrgy dmand. In rcn yars a growg rs has bn addrssd o zro nrgy homs or buildgs ha produc mor nrgy han ha hy consum. Th ffors o aa his goal hav producd a progrssiv graion of rnwabl and convnional nrgy sourcs. This mans ha nw chnologis, such as solar plans, biomass plans, gohrmal ha pumps, co/ri-gnraors, ful clls, ar spradg rapidly. Th applicaion of hs chnologis lads o a sor of buildg ha can b rfrrd o as a muli-nrgy sourc buildg, sc h hrmal, coolg and lcrical loads ar covrd by a mix of nrgy sourcs, a las on of hm rnwabl. Th aim is o dsign and manag such sysms wih h bs fficcy []. I is ncssary o vsiga h couplg bwn a buildg, characrizd by nrgy dmand profils for hag, coolg and lcriciy, and a sysm, characrizd by producion profils (solar, wd, lcriciy, c ). Th sudy of h graion of diffrn nrgy sourcs buildgs has o b h formos ordr o fully xploi h nrgy savgs ponial of rnwabl sourcs. Bg conscious ha h dgr of h dsign ffor is grar durg h program pr-dsign and schmaic dsign phass [2], i is of a gra imporanc o concnra h rsarch aciviis on h laboraion of a mhodology o modl and opimiz h couplg bwn nrgy dmand and nrgy supply a buildg a h dsign concp phas.

2 rocdgs of Clima 2007 WllBg Indoors MULTI-ENERGY SOURCE BUILDING SYEMS Svral xampls of muli-nrgy sourc buildg sysms can b found liraur, combg cognraion wih solar nrgy (boh hrmal and V) and wih wd nrgy [3], xploig gohrmal and solar nrgy hrough solar assisd ha pumps [4], combg CH wih absorpion chillrs and dsiccan coolg [5], xploig solar nrgy o produc boh hag and coolg [6], xploig wd nrgy hrough a ful cll sack [7]. On of h ma problms of a muli-nrgy sysm [8] is h mismach bwn nrgy supply and nrgy dmand. This is spcially ru for rnwabl sourcs. This problm, as for h plans ha xploi solar nrgy o produc cold [6], is usually dal wih h graion of a sorag. Typical sorag mdiums ar war (rfrigrad or ic), ground, CM or hydrogn. As an xampl, h wd ful cll hybrid nrgy sysm dscribd [7] lcriciy surplus providd by a wd urb is uilizd o produc hydrogn ha is usd, lar whn ncssary, a ful clls sack, which also rprsns a cognraion sysm. Th objcivs of muli-nrgy sysms ar h followgs [8]: o rduc h primary nrgy consumpion; o produc nrgy on si; I is ou of doub ha h nar fuur his kd of sysms will b usd boh for nw buildgs and for rnovaions. MULTI-ENERGY SOURCE BUILDING SYEM MODELLING Th prsnd modllg approach o muli-nrgy sysms buildgs is basd on h concp of hybrid nrgy hub, which was dvlopd by Andrsson, Fröhlich, Gidl al. [9,0] o modl and opimiz h muli-carrir nrgy nwork of h fuur []. Th buildg is modlld as an nrgy sysm ha is supplid wih diffrn nrgy carrirs and mus m hag, coolg and lcrical loads. Th couplg bwn h sourcs (pus) and h loads (oupus) is sablishd by a couplg marix ha dpnds on h chnology and on h convrsion fficcis of sysms and plans salld. Wih h sam modllg approach, diffrn lvls of complxiy ar possibl dpndg on h pu daa and on h couplg marix nris. Wih rfrnc o h opimizaion of a muli-nrgy sourc buildg sysm h dsign concp phas, h daa slcd o modl flow and convrsion of nrgis wih h hub ar h dsign powr and h annual (or sasonal) nrgy E. Each nrgy carrir is idnifid by a suprscrip (.g. for lcriciy, for hrmal). Th subscrip idnifis h dmand (ou) or h supply (). Th couplg bwn nrgy dmand and nrgy supply can b wr as E = D E ou whr E is h vcor of nrgy pus [E, E, ] T, E ou is h vcor of nrgy oupus [E ou, E ou, ] T and D is h couplg marix which dpnds on sysms and plans salld and on hir convrsion fficcis. Th sam rlaion can b wr for dsign powr, assumg dsign fficcis sad of man sasonal fficcis. Each marix nry d ab accouns for boh conncion and convrsion fficcy bwn nrgy carrirs. A valu of d ab qual o 0 mans ha no conncion bwn h nrgy carrir a and nrgy carrir b is providd by h hub; a valu of d ab qual o mans ha all powr of nrgy carrir a flows o nrgy carrir b wihou convrsion losss.

3 rocdgs of Clima 2007 WllBg Indoors Muli-nrgy sourc buildg sysm modllg applicaion procdur Th applicaion procdur o modl a muli-nrgy sourc buildg sysm is h followg: ) idnify h s of availabl nrgy sourcs and h s of buildg loads; 2) idnify h componns ha can b usd o covr h buildg loads, givn h s of nrgy sourcs availabl: his can lad o wo diffrn approachs: 2.) a gnric hub which aks o accoun all convrsions (and h rlaiv componns) ha nrgy sourcs can undrgo bfor covrg h loads; 2.2) a ailord hub which aks o accoun only h convrsions (and h rlaiv componns) ha ar of pracical applicaion and of rs o h buildg ownr; 3) idnify all h paramrs (such as fficcis) ha can modl h prformanc of h componns boh a h dsign condiion and a opraional condiions, and assign o hm a numric valu; 4) df h coss of h nrgy-wars and of h chnologis adopd; 5) prform an opimizaion o slc h bs muli-nrgy sysm. MULTI-ENERGY SOURCE BUILDING SYEM OTIMIZATION Svral criria can b adopd o opimiz a muli-nrgy sourc buildg sysm. Som of hm ar h followgs: - rduc h runng coss; - rduc h capial coss; - rduc h amoun of nrgy consumd a priod of im; - maximiz h fficcy of h sysm (boh rms of nrgy and of xrgy); - rduc h nvironmnal impac of h buildg and srvics; - maximiz h us of naural rsourcs ha ar availabl a no cos. Th mos appropria opimizaion cririon for h dsign concp of a muli-nrgy sourc buildg sysm h dsign concp phas sms o b h conomic approach. I has bn adopd h cas sudy prsnd. Two diffrn procdurs can b ould. Th firs on is basd on h n prsn valu calculaion. Th procdur sps ar h followgs: ) s a rfrnc configuraion (convrrs, allowabl convrsions, powr flows, dsign powrs of h convrrs) of h sysm; 2) s h priod (numbr of yars) for h vsmn analysis; 3) drm h capial cos diffrnc and h runng cos diffrnc bwn alrnaiv scnarios and h rfrnc cas; 4) calcula h n prsn valu for ach scnario basd on capial and opraional cos diffrncs ovr h fixd priod. As rgards h dsign alrnaivs, usually afr a grar capial cos h firs yar, savgs on runng coss ar xpcd. Th opimal scnario is h on ha has h grar n prsn valu (his comparison can b don if all n prsn valus ar calculad assumg h sam priod of im. Th drmaion of h rnal ra of rurn (IIR) is also usful. Th scond procdur nds o mimis a yarly cos basd on h sum of on yar runng coss and of h vsmn coss dividd by h yars of xpcd lif of ach componn. This procdur can b implmnd wihou dfg a rfrnc configuraion of h sysm. In any cas, h lifim of componns salld mus b dfd ordr o compar capial and runng coss.

4 rocdgs of Clima 2007 WllBg Indoors ALICATION TO A CASE UDY Th mhodology prsnd has bn applid o h dsign of h nrgy sysm srvg h Valcasoo casl idmon. A ailord nrgy hub procdur has bn carrid ou as follows: ) Th availabl nrgy sourcs ar: wood (w), LG and lcriciy () from h nwork; h buildg hrmal and h lcric load ar o b covrd. Four dmand scnario (h firs on considrg hrmal nrgy only) hav bn idnifid rms of dsign powr ou and annual dmand E ou and ar rpord Tabl. 2) Th convrrs ha can b usd o covr h buildg loads ar a wood boilr (), a boilr (B), an rnal combusion ng () and a sam urb (). Th rnal combusion ng and h sam urb provid boh lcriciy and ha. Th hapowr raios ar rspcivly and 2. Th rnal combusion ng is fd ihr by wood hrough a wood gasifir (WG) or by LG. Th sam urb is considrd o b an nsmbl of a wood boilr and a sam urb. Th schmaic rprsnaion of h nrgy hub considrd is dsignd Figur. Th coffics rprsn h load fracions covrd by a cra convrr (h suprscrip idnifis h nrgy carrir, h subscrip h convrr): for xampl rprsns h fracion of h hrmal load covrd by h oupu of h wood boilr. 3) Th fficcis of h componns (dividd o hrmal and lcrical for cognraion convrrs) ar rpord abl 2 cludg boh dsign fficcis and yarly man fficcis. Tabl. Componns of ou and E ou vcors (rspcivly kw and MWh/yar) Enrgy Scnario Scnario 2 Scnario 3 Scnario 4 ou E ou ou E ou ou E ou ou E ou Thrmal Coolg Elcriciy Figur. Schmaic rprsnaion of h Valcasoo ailord nrgy hub

5 rocdgs of Clima 2007 WllBg Indoors Tabl 2. Dsign fficcis and man annual fficcis of h convrrs Dsign fficcy Man fficcy B 0.95 B 0.85 WG 0.75 WG Afr havg dfd h fficcis of ach convrr (for xampl is h hrmal fficcy of h rnal combusion ng) h pu powrs a h nranc por of h hub can b drmd summg up h conribuions of ach convrr as follows: w LG = GCL = = B ou B ou ou ou ( k) ( k) ou ou / 2 k ou WG / 2 ou k WG ou / 2 () Assumg a lar corrlaion bwn pus and oupus, his can b rwr a marix form as w LG = 2 B B k WG 2 k 2 2 ( k) 0 ( k) 0 0 WG ou f ou ou, (2) whr h producs rlaion, ou and, ou ar rlad, h cas of a cognraor, by h,,, ou =, ou, (3) ha mus b cludd as a furhr quaion o (3) ordr o modl h hub prformanc. Th opimisaion of h hub can b prformd by mimizg h objciv quaion C y ( E, k ) = f (4) which aks o accoun h nrgy coss a priod of im and h capial cos of h convrr dvics salld. I is hrfor ncssary o drm h dsign powr of ach convrr k and hn (5) can b rwr as:

6 rocdgs of Clima 2007 WllBg Indoors w w LG LG c cb B c cwg WG c m C = y m c E c E c E (5) y yb y ywg y whr cos for nrgy consumd c, coss of convrrs ( rms of dsign powr) c k ar rsumd abls 3 and 4. Th xpcd numbr of yars is fixd o 20 yars for ach convrr. Th mimisaion of his yarly cos funcion has bn prformd by mans of a commrcially availabl rducd grad mhod algorihm. Th problm is hn o fd h valus of ha mimiz h cos funcion α i : m f ( E, ) k undr h consra of h hub: E = D E ou ; = D ou E > 0 ; > 0 and h consras rlaiv o h coffics: { GCL, GC, ME...} 0 α i α, i, α i = α i ME, TV 2 = ME, TV 2 ME, TV ME, TV Tabl 3. Cos srucur c of h nrgy wars Enrgy-war [ /kwh] Wood 0.04 LG Elcriciy 0.50 Tabl 4. Cos srucur c k of h nrgy convrrs Enrgy convrr [ /kw] Wood boilr 200 Boilr 00 Wood gasifir Gas urb 00 Elcriciy 00 Th rsuls of h opimizaion of ach scnario ar shown figur 2. Th modl can b usd o simula, for a givn dmand scnario, ohr hub srucurs. In h cas of scnario numbr 2, i is possibl o drm h primary nrgy ha mus b supplid usg h rnal combusion ng fd by gas via h wood gasifir or h rnal combusion ng fd by LG sad of h wood gasifir and h sam urb. This can b don by fixg h valus of coffic sad of lg hm o frly chang as h opimisaion. Thos wo alrnaiv scnarios simulad ar prsnd figur 3 and i can b vrifid ha h rsulg valus of C y ar highr han ha of h opimizd configuraion.

7 rocdgs of Clima 2007 WllBg Indoors Figur 2. Schmaic rprsnaion of h Valcasoo ailord nrgy hub opimizd for four diffrn dmand scnarios ( o 4 from righ o lf) Figur 3. Schmaic rprsnaion of wo furhr simulaion of h Valcasoo ailord nrgy hub for h scond dmand scnario DISCUSSION A modllg approach o muli-nrgy sysms buildgs has bn prsnd. I is basd on h concp of h hybrid nrgy hub has bn cusomisd o b usd h dsign concp phas. Th modl is qui simpl and allows analysis o b prformd prsnc of dsign powr and annual or sasonal nrgy dmand daa only. Such a modl ms h rquirmns of simpliciy ha characriz h dsign concp phas, bu a facor of uncray is rprsnd by h choic of h valus of h fficcis. Valus of man sasonal fficcis graly affc h rsuls and appropria valus of hs propris ar difficul o drm a priori and mus b basd on h consulan xprc. Furhr rsarch aciviy is currnly carrid ou o ovrcom his drawback; valus of fficcis dpndn on dsign powr salld and on h par load raio may b grad o h modl.

8 rocdgs of Clima 2007 WllBg Indoors REFERENCES. Virgon, J, Fabrizio, E, Raffnl, Y, al Command ds sysèms muli-énrgis pour ls bâimns à hau prformanc énrgéiqu. roc. of SFT-IBSA Franc Congrss Efficacié énrgéiqu ds bâimns. Vrs ds bâimns auonoms n énrgi, Chambéry, 2 March Lwis, M Ingrad dsign for susaabl buildgs. ASHRAE Journal. Vol. 46 (9), pp S22-S Sonag, R and Lang, A Cos ffcivnss of dcnralizd nrgy supply sysms akg solar and wd uilizaion plans o accoun. Rnwabl Enrgy. Vol. 28 (2), pp Trilla-Brdal, V, Souyri, B and Fraiss, G Exprimnal sudy of a ground-coupld ha pump combd wih hrmal solar collcors. Enrgy and Buildgs. Vol. 38 (2), pp Liu, XH, Gng, KC, L, BR and Jiang, Y Combd cognraion and liquid-dssican sysm applid a dmonsraion buildg. Enrgy and Buildgs. Vol. 36 (9), pp Hnng, H-M, Solar assisd air condiiong of buildgs an ovrviw. Applid Thrmal Engrg. (2006), doi:0.06/j.applhrmalng Iqbal, MT Modlg and conrol of a wd ful cll hybrid nrgy sysm. Rnwabl Enrgy. Vol. 28 (2), pp Filippi, M, Corgnai, S, Fabrizio, E Impianisica sosnibil: dai sismi mononrgia ai sismi mulrgia [Susaabl buildg srvics: from on nrgy o muli-nrgy sourc sysms]. Cda (Condizionamno dll aria, riscaldamno, rfrigrazion, ISSN ) (2), pp Gidl, M, Andrsson, G. (2005). A modllg and opimizaion approach for mulipl nrgy carrir powr flow. roc. of IEEE ES Inrnaional Confrnc on Elcric owr Engrg (owrtch), S. rsburg, Russia. 0. Klöckl, B., Fröhlich, K., Kalnggr, K. (2005). Nw nrgy chnologis, nw rquirmns on lcriciy and an unrsolvd ransiion problm owards susaabiliy: is hr a nd for basic acadmic rsarch?. Cigré 5h Souhrn Africa Rgional Confrnc, Ocobr 2005, Cap Town, Souh Africa.. Favr-rrod,, Gidl, M, Klockl, B, Koppl, G A vision of fuur nrgy nworks. roc. of IEEE ES 2005 Confrnc, Durban, Souh Africa, -5 luglio 2005, pp 3-7.