Energy-saving potential deriving from the use of a manifold with flow rate dynamic balancing

The ce tra p i t is t i terve e effective y with ut bri gi g with y u the side effects f the u ba a ci g f f ws that are irregu arity f the p wer distributi ise a d fi a y e ergy u efficie cy These types f pr b e are particu ar y evide t i the case f the high differe tia pressures typica f very arge etw r s The perati f the variab e f w pu p ca certai y itigate this aspect h wever by acti g y e ergy savi g it ca t i fact i terve e i the ba a ci g i a y way The tech ica appr aches are substa tia y tw the first re tied t traditi that is the use f the differe tia pressure c tr er i c bi ati with a static ba a ci g va ve u ted upstrea f a sta dard a if d the sec d re i vative a d si p e is i stead the use f a if ds with i tegrated cartridge f r dy a ic ba a ci g i each si g e circuit The app icati with this type f s uti has a y perati a a d a ageria adva tages The dy a ic ba a ci g a if ds are equipped with i tegrated cartridges that regu ate a d i it the f w t preset va ues The preset f w rate the si g e circuit wi t exceed eve if there are ad cha ges i side the syste due t the c si g f ther va ves r duri g the first start up Withi a i i u a d axi u differe tia pressure ra ge this perati is c p ete y i depe de t fr the differe tia pressure This type of intervention, inserting a dynamic balancing manifold in spite of a standard one, is infinitely simpler than installing differential pressure controllers upstream of the manifolds and ultimately much more precise. Since the required flow rate can be preset directly on the individual circuit by means of an adjustment key, complicated calculations of pressure drop and balancing are no longer necessary, finally the commissioning time is clearly reduced.


Summary
Havi g t desig a d p a bui di g re vati s f differe t ature fr arge ce tra i ed i sta ati s t s a apart e ts i the c text f a if d distributi especia y f r radia t app icati s the ai the e is t ba a ce the f ws i a c rrect a d i i a y i vasive way The ce tra p i t is t i terve e effective y with ut bri gi g with y u the side effects f the u ba a ci g f f ws that are irregu arity f the p wer distributi ise a d fi a y e ergy u efficie cy These types f pr b e are particu ar y evide t i the case f the high differe tia pressures typica f very arge etw r s The perati f the variab e f w pu p ca certai y itigate this aspect h wever by acti g y e ergy savi g it ca t i fact i terve e i the ba a ci g i a y way The tech ica appr aches are substa tia y tw the first re tied t traditi that is the use f the differe tia pressure c tr er i c bi ati with a static ba a ci g va ve u ted upstrea f a sta dard a if d the sec d re i vative a d si p e is i stead the use f a if ds with i tegrated cartridge f r dy a ic ba a ci g i each si g e circuit The app icati with this type f s uti has a y perati a a d a ageria adva tages The dy a ic ba a ci g a if ds are equipped with i tegrated cartridges that regu ate a d i it the f w t preset va ues The preset f w rate the si g e circuit wi t exceed eve if there are ad cha ges i side the syste due t the c si g f ther va ves r duri g the first start up Withi a i i u a d axi u differe tia pressure ra ge this perati is c p ete y i depe de t fr the differe tia pressure This type of intervention, inserting a dynamic balancing manifold in spite of a standard one, is infinitely simpler than installing differential pressure controllers upstream of the manifolds and ultimately much more precise.
Since the required flow rate can be preset directly on the individual circuit by means of an adjustment key, complicated calculations of pressure drop and balancing are no longer necessary, finally the commissioning time is clearly reduced.

Introduction
The study as described below has as a target the identification of the potential energy savings due to the correct delivery of thermal loads in the rooms by the use of the manifold system technology with "dynamic balancing of the flow".
The study is expressed through the development of two exemplary cases, indicated as "individual" and "collective". The "individual" case examines the typical situation of the internal effects of a single housing unit, a case that can occur with a villa or apartment with an independent system. Conversely, the "collective" case examines the typical situation of collective / multi-family residential buildings (condominiums, for example) with centralized systems where energy saving is linked to the dynamics induced by the energy behavior of the individual units.

Case 1 -Energy savings according to the "individual" model (endogenous)
"et's c sider a h usi g u it (f r exa p e a si g e fa i y h e r a apart e t with a i depe de t heati g syste ) that uses a w i ertia radia t f r as its heati g syste The distributi f the heat tra sfer f uid t wards the vari us radia t circuits ccurs thr ugh a si g e a if d that represe ts the starti g p i t f the c i s servici g the r s f tw "ther a areas" the ivi g area ( itche ivi g r a d bathr ) a d the s eepi g area (bedr 1 bedr 2 a d fa i y r )de ) Each ther a area is c tr ed via a e ther stat cated i a r c sidered the "pi t" r a d se ected as represe tative the ivi g r f r the ivi g area a d the fa i y r )de f r the s eepi g area The sig a received by the ther stats c tr s the c tr va ves f the c rresp di g r s i the ivi g a d s eepi g areas Give that g a d are the subscripts used t specify respective y the ivi g a d s eepi g area , is the apex used t specify the desig c diti s ci is the fracti f t ta f w rate f the heat tra sfer f uid f wi g i the i th circuit p is the subscript used t specify the "pi t" r s p is the subscript used t specify the " pi t" r s -w i desig c diti the vera f w rate is m*tot = m*n + m*g and, by the effect of the size of the rooms and their thermo-physical characteristics, it is distributed in designed conditions according to a specific percentage, for example: 60% -> living area 40% -> sleeping area Therefore: m*n = x m*tot where x=0.4.
We ca w assu e that at the ti e t1 e g at 10 a i the pi t r f the ivi g area the Tsp set p i t te perature is reached As a resu t the va ves i the ivi g area wi c se thus st ppi g the f w the c rresp di g circuits If a "f w rate dy a ic ba a ci g" a if d is t used the f w rate desti ed t the ivi g area wi w be redistributed t the s eepi g area (a dr p due t a i creased ss f pressure ca ccur but this effect t c sidered herei as a i itia appr xi ati ) "et us assu e that the , f w rate circu ati g i the s eepi g area circuits is distributed acc rdi g t a desig perce tage f r exa p e The vera f w rate u der the ew perati g c diti s circu ati g i the s eepi g area is w m'notte = m*n + m*g = m*tot where ,t t is the t ta desig f w rate which wi circu ate acc rdi g t the perce tages specified ab ve f r each f the three r s f r i g the "s eepi g" area Further re et us c sider that by the effect f the i tri sic tre d f radia t heati g syste s t re ba a ce the p wer supp ied i the ew perati g c diti s the i crease i f w rate c rresp ds t a reducti i DT' c pared t the desig DT, Now, let us assume that: due t the e d ge us a d ex ge us heat f ws the te perature i the pi t r f the iv i g area re ai s higher tha the set p i t te perature f r -h urs duri g the day (f r exa p e fr 9 00 a t 4 00 p thus -66) • i the sa e -h urs the pi t r f the s eepi g area ever reached the set p i t te pera ture (c seque t y a f w rate exceedi g the desig e c ti ues t circu ate i the "s eepi g" circuits) • whi st i the tw ther r s the te perature exceeds the estab ished te perature f r 9 h urs -w et us express the f w rate i the s eepi g area acc rdi g t the desig c diti as m*notte = a m*notte + b m*notte where a + b = 1 where a is the f w rate fracti f the s eepi g area circu ati g i the "pi t" r circuit a d b i the " pi t" es Si i ar y ' tte 6 a ' tte ; b ' tte I the r s f the " pi t" s eepi g area (subscript p) theref re u der the desig c di ti s the ther a p wer supp ied w u d be equa t Q*np,n = (b m*notte ) cp DT* = (b x m*tot ) cp DT* I stead i the af re e ti ed c diti where the set p i t te perature is t reached i the pi t r the f wi g perati g c diti w u d ccur Q'np,n = (b m'notte ) cp DT' = (b m*tot) cp (y DT*) si ce ' tte 6 ,t t Whe the desired te perature is reached i the " pi t" r but the ther a p wer c ti ues t be supp ied i the r as the set p i t te perature is t reached i the "pi t" r f the s eepi g area we wi have the f wi g situati 1 -a f w rate bei g supp ied t the r exceedi g the p a ed e expressed as D m'np,n = b (1-x) m*tot 2 a c rresp di g ver p wer bei g supp ied t the r equa t D Q'np,n = b (1-x) m*tot cp y DT* -w assu i g that this c diti ccurs f r 9 h urs duri g the day (where 9=6-) the resu t i ter s f idea ther a e ergy > Wh? duri g the day u der desig c diti s is E*tot = m*tot cp DT* 24 whi e i the prese ce f ver p wer supp ied f r 9 h urs a ver ad situati ccurs equa t D E'np,n = b (1-x)  By i g at this fr the pp site p i t f view this ver c su pti c rresp ds t the E-ERGY SAVI-GS btai ab e thr ugh the use f a "f w rate dy a ic ba a ci g" a if d wi g tab e sh ws acc rdi g t a "se sitivity a a ysis" gic the resu ts f the p te tia e ergy savi gs btai ab e by effect f a cha ge i the para eters affecti g the de

Case 2 -Energy savings according to a "collective" model (exogenous)
"et us c sider a u ti fa i y bui di g sp it i t h usi g u its (f r exa p e a c d with 8 apart e tsF a e a i e f r p us 3 ther f rs with 2 apart e ts per f r) with a ce tra i ed heati g syste servi g a h usi g u its which have a w i ertia radia t f r as HVAC syste The distributi f the heat tra sfer f uid fr the b i er r t the h usi g u its ccurs via a pri ary circuit f heati g h t water that serves the apart e t a if ds each apart e t is served by a dedicated a if d I each apart e t each a if d is c ected t the vari us radia t circuits wh se c i s serve the r s f the apart e t (f r exa p e itche ) ivi g r fa i y r bathr bedr 1 a d bedr 2) Give that g a d are the subscripts used t specify respective y the ivi g a d s eepi g area , is the apex used t specify the perati g c diti s f the pr Hect , the apex used t specify the perati g c diti s u der review ci is the t ta f w rate fracti f the heat tra sfer f uid f wi g i the i th circuit p is the subscript used t specify the "pi t" r s p is the subscript used t specify the " pi t" r s cp is the subscript used t specify the "pri ary circuit" 1 is the subscript used t specify the h usi g u its (apart e ts) f the bui di g I the subscript used t specify the ge eric i th h usi g u it -w et us c sider the heati g circuit The t ta f w rate supp ied by the pri ary circuit ac c rdi g t the desig c diti s is ,t t 6 ,1 ;…; , which by effect f the si e f the apart e ts a d their ther physica characteristics is dis tributed u der the p a ed c diti s acc rdi g t a specific app rti e t f r exa p e m*i = zi m*tot where i is the t ta f w rate fracti t the a if d f the i h usi g u it give that z1 + … + zn = 1 If u der desig c diti s the f w rate is equa y distributed ver each apart e t the zi = z1 =… = zn = 1/n The ther a p wer supp ied by the syste u der desig c diti s sha the be expressed as Q*tot = m*tot cp DT* = z1 m*tot cp DT* + …. + zn m*tot cp DT* where DT, is the desig te perature gradie t the syste ter i a -w et us supp se that the apart e ts (e g equa t 8) are ccupied by h useh ds havi g the f wi g pr fi e by way f exa p e • Type A apart e ts (e g 3) ccupied by retirees wh eep the heati g syste c ti u us y thr ugh ut the day • type B apart e ts (e g 5) ccupied by fa i ies with w r i g pare ts a d sch age chi dre where these fa i ies tur ff the heati g syste f r a ti e i terva f H h urs e g fr 8 00 a t 2 00 p h urs (6 h urs ff) If "f w rate dy a ic ba a ci g" a if ds are t used duri g the H h urs f the heati g sys te tur ed ff by type B apart e ts the f w rate previ us y desti ed t the vari us h usi g u its wi be redirected t type A h usi g u its (u ess there is a dr p due t a i creased ss f pressure a effect t c sidered herei as a i itia appr xi ati ) Thus m'tot, tipoA = m*tot where ,t t is the desig t ta f w rate By way f exa p e et us c sider the case f 8 t ta apart e ts f which 3 f type A the at ter wi have w a t ta f w rate sp it i t perce tages f r each f the af re e ti ed 3 apart e ts (ide tified with subscripts 1 3 5) 9 re specifica y it is assu ed that zi* = z1 =… = z8 = cost = 1/8 z'i, tipoA = z'1 = z'3 = z'5 = cost = 1/3 I this case the f w rate each f the 3 type A apart e ts wi be equa t m'1 = m'3 = m'5 = z'i, tipoA m*tot = 1/3 m*tot -w et us f cus e f the type A apart e ts We ca assu e that the type A apart e t u der review is desig ed as a si g e "ther a e" c tr ed by a si g e r ther stat p aced i a "pi t" r ch se as represe tative f r exa p e "bedr 1" with rther exp sure ge era y characteri ed by i ited ex ge us a d e d ge us effects U der desig c diti s et us assu e that the f w rate circu ati g i the circuits f the apart e t (re i der ,i 6 i ,t t) is distributed acc rdi g t a perce tage ca cu ated acc rdi g t the pr Hect as f ws • "pi t" r a 6 0 2 theref re 20% f the f w rate circu ati g i the apart e t • ther " pi t" r s b 6 0 8 thus 80% f the f w rate circu ati g i the apart e t U der the ew perati g c diti s the t ta f w rate circu ati g i the type A apart e t is as sh w ab ve m' = z'i, tipoA m* where ,t t is the p a ed t ta f w rate that wi circu ate distributed i perce tage ( 'i tip A ) f r each f the 3 type A apart e ts Further re et us c sider that by the effect f the i tri sic tre d f the radia t heati g sys te s t re ba a ce the p wer bei g supp ied u der the ew perati g c diti s the i crease i f w rate c rresp ds t a reducti i DT' c pared t the desig DT, DT' = y DT* where (1-x) < y < 1 -w et us assu e that • duri g the H h urs f tur ff ti e i type B apart e ts i the pi t r f the type A apart e t the set p i t te perature is ever reached (c seque t y duri g said H h urs a f w rate equa t ' 6 'i tip A , higher tha the p a ed e wi c ti ue t circu ate i the cir cuits f the type A apart e t ) • at the sa e ti e i the ther " pi t" r s f the type A apart e t the te perature ex ceeds f r 9 h urs (with 9=6 H) the estab ished te perature desired -w et us express the f w rate f the type A apart e t acc rdi g t the p a ed c diti as m* = a m* + b m* being a + b = 1 where as a ready defi ed bef re a is the f w rate fracti circu ati g i the "pi t" r cir cuit a d b i the " pi t" es Si i ar y u der the ew perati g c diti s m' = a m' + b m' Theref re u der the desig ed perati g c diti s the ther a p wer supp ied i the " pi t" r s (subscript p) w u d be equa t Q*np = (b m*) cp DT* = (b zi* m*tot) cp DT* I stead u der the perati g c diti s described ab ve where the set p i t te perature is ev er reached i the pi t r duri g the H h urs whe the type B apart e ts are switched ff the f wi g perati g c diti w u d ccur

Summary of Results
The de deve ped a wed esti ati g the e ergy savi g p te tia ass ciated with the use f a "f w rate dy a ic ba a ci g" a if d With refere ce t the tw cases reviewed a d bac gr u d c diti s (i put a d characteristic para eters f the de ) reviewed • the Ni dividua O case pr vidi g a exa p e f e ergy savi gs f r h usi g u its with a i de pe de t heati g syste sh wed e ergy savi gs up t 12%F • the Nc ectiveO case pr vidi g a exa p e f e ergy savi gs f r u ti fa i y bui di gs with a ce tra i ed heati g syste sh wed e ergy savi gs up t 25%

Conclusions
The fr tier f deve p e t with a view t e ha ci g e ergy savi gs sees dy a ic f w ba a ci g syste s t have pri ary p ace a d p siti But they d t pr ceed a e but certai y c up ed with w thic ess a d w i ertia sys te s It is i fact thr ugh the c bi ati f the effect f w ther a i ertia a d the dy a ic c tr f the f w rate that the best effects are btai ed The dy a ic ba a ci g f the f w certai y has a p te tia e ergy i pact that is i p rta t as de strated i the study we i tr duced ab ve The target is t a e the ba a ce usab e a d easy t app y i ew a d existi g app icati s A syste with dy a ic ba a ci g a if ds is ab e t eep the f w rate a ways ba a ced f r a syste circuits thus c tributi g t the reducti f verf ws a d c seque t y t a ap preciab e e ergy savi g Pvera di e si s a d app icati s are th se f a sta dard a if d but the cartridge i sta ed i each circuit perates the f wi g fu cti s • f w c tr whe the pressure varies due t the pe i g r c si g f s e circuits the dia phrag f the cartridge va ve i terve es by varyi g its passage secti a d adapti g the f w t the preset va ue eve i the prese ce f high differe tia pressures • f w rate pre setti g it is p ssib e t set the axi u desig f w rate f r each i dividua circuit which ust be ept c sta tF • r te perature pti i ati the c bi ati with e ectr ther ic heads a d r ther stats a ws t pti i e te perature a age e t i the vari us r s It is i deed thr ugh si p e a d re iab e app icati s such as a if ds that dy a ic ba a ci g tech gy ca a e us achieve a step f rward i c st pti a ity appr ach