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Applications Engineer ing Manual Chiller S yst em Design and Contr ol May 2009 SYS - A P M 0 01- E N.
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Chiller S yst em Design and Contr ol Susanna Hanson, appl ications engineer Mick Sc hwedler , applications manag er Beth Bakkum, infor mation designer.
© 20 09 T rane All rights reserved Chiller Syste m Design and Control SYS-APM00 1 -EN T ran e, in proposing these syst em design and application con cepts, assumes no responsibility for the performance or desir ability of any resulting syst em design.
SYS-APM00 1 -EN Chiller System Design and Control iii Cont ents Pr ef ace .... ................ ................ ................ .................... ................ .......... i Pr imary Syst em Components .............. ................ ..........
iv Chiller System Design and Control S YS-APM001 -EN S ystem Contr ols ................. .................... ................ ................ ...... 87 Chilled-W ater S ystem Control ..................... ................ ................... 87 Condenser -W ater System Control .
SYS-APM00 1 -EN Chiller System Design and Control 1 Pr imary S yst em Components Chilled-water systems consist of these functional par ts: • Chillers that cool the water or fluid • Loads, often sa.
2 Chiller System Design and Control S YS-APM001 -EN Pr imary Syst em Components Figure 1. Typical vapor-compression chiller W ater -cooled c hiller s are typically inst alled indoors; air -cooled c hillers are typically installed outdoors—either on the ro of or next to the building.
Pr imary Syst em Components SYS-APM00 1 -EN Chiller System Design and Control 3 • In a direct-expansion (DX) shell-an d-tube evaporator (F igure 3), warmer water fills the shell while the cool, lo wer -pressure liquid refrigerant flows through the tubes.
4 Chiller System Design and Control S YS-APM001 -EN Pr imary Syst em Components Some c hiller controls can accom modate very little flow variation during mac h ine operation.
Pr imary Syst em Components SYS-APM00 1 -EN Chiller System Design and Control 5 While they found that so me of the internally - enhanced tubes fouled in the long term, they c oncluded: Because of the .
6 Chiller System Design and Control S YS-APM001 -EN Pr imary Syst em Components Low -ambient operation Air -cooled c hillers are often selected for use in systems with year -round cooling require ments that cannot be met with an air side econom izer .
Pr imary Syst em Components SYS-APM00 1 -EN Chiller System Design and Control 7 Figure 4. Air-cooled or water-cooled efficien cy Another advantage of an air -cooled c h iller is its delivery as a “pac k aged system.
8 Chiller System Design and Control S YS-APM001 -EN Pr imary Syst em Components Heat transferred fro m the loads can be controlled in a number of ways: • Three-way valve •T w o - w a y v a l v e .
Pr imary Syst em Components SYS-APM00 1 -EN Chiller System Design and Control 9 Figure 6. Two-way valve V ariable-speed pump load contr ol By using a pump for eac h coil (Figure 7), the flow may be controlled b y varying the pump speed. In suc h system s, there may be no control valves at the coil.
10 Chiller System Design and Control S YS-APM001 -EN Pr imary Syst em Components pumped all the time; however , in syst ems with very small water pressure drops, this syst em arrangem ent may work economically .
Pr imary Syst em Components SYS-APM00 1 -EN Chiller System Design and Control 11 • accommodates the total pressure (sta tic head plus dynamic head) on system components suc h as the c hiller ’ s evaporator , valves, etc. Note that the pump heat is added to the w ater and must be absorbed by the c hil ler .
12 Chiller System Design and Control S YS-APM001 -EN Pr imary Syst em Components valves may be either three-way or two -w ay . As previousl y discussed, t hree- way valves require constant w ater flow , while two-w ay valves allow the w ater flow in the system to vary .
Pr imary Syst em Components SYS-APM00 1 -EN Chiller System Design and Control 13 the series, or another pu mping arrangement can be considered. Reducing the flow rate af fects this system type’ s energy use all the time, so careful attention to flow rates an d temperature is critical (refer to “System Design Options” on page 27).
14 Chiller System Design and Control S YS-APM001 -EN Pr imary Syst em Components water entering and leaving the cooling tower is th e range. The temperature difference between the leaving w ater temperature and the ente ring wet-bulb temperature is the approac h.
Pr imary Syst em Components SYS-APM00 1 -EN Chiller System Design and Control 15 Unit-Lev el Contr o ls The c hilled-water supp ly temperature is usually controlled by the c hiller . Most commonly , supply water temperatur e is used as the sensed variable to permit contro l of c hiller capacity to meet syst em load demand.
16 Chiller System Design and Control S YS-APM001 -EN Pr imary Syst em Components In addition to m onitoring data, it is vital that the c hiller controls aler t operators to possible problem s. Diagno stic messages are necessary for the operator to respond to safe ty issues and data points that are outside normal operating rang es.
Pr imary Syst em Components SYS-APM00 1 -EN Chiller System Design and Control 17 by reducing m otor speed at “low-lift” conditions, when cooler condenser water is available.
18 Chiller System Design and Control S YS-APM001 -EN Application Consider ations Chiller system siz e affects design and control cons id erations. Eac h size comes with its own set of advantages and challenges. Small Chilled-W a t er Syst ems (1 -2 c hillers) Figure 17.
Application Considerations SYS-APM00 1 -EN Chiller System Design and Control 19 Constant flo w Constant flow is simple and often applied to small systems up to 20 0 tons— as long as the system pres sure drop is fairly l ow and a wider T is applied to reduce the system flow rate.
20 Chiller System Design and Control S YS-APM001 -EN Application Considerations part of those jobs. S e e “Energy and ec onomic analy sis of alternatives” on page 26. Number of c hillers The number of c hillers to install is a functio n of redundancy requirements and first cost.
Application Considerations SYS-APM00 1 -EN Chiller System Design and Control 21 than at full load. V ariable frequenc y d rives for unloading tower fans and c hilled-water pumps may p rovide benefi ts, depending on the costs, system operating hours, system type, and outdoor air condit ions.
22 Chiller System Design and Control S YS-APM001 -EN Application Considerations but use it sparingl y due to its low er efficiency . Or , a c hiller may have a different fuel source, used as a hedge against either high demand or high energy consumption c harge s for other energy sources.
Application Considerations SYS-APM00 1 -EN Chiller System Design and Control 23 Creating one centraliz ed c hilled-wa ter system takes signif icant foresight, initial in vestment, and building devel opm ent with a multi-year master plan.
24 Chiller System Design and Control S YS-APM001 -EN Application Considerations T o minimiz e power , large systems must be very effi cient. Th e upside of a large system is the am plification of energy savin gs. A relatively small percentage of energy saved becomes more valua ble.
Application Considerations SYS-APM00 1 -EN Chiller System Design and Control 25 Guidelines for syst em efficiency monit or ing ASHRAE Guideline 22 Instrumentation for Mon itoring Central Chille d-W ater Plant Effic iency 6 w as first published in June 20 08.
26 Chiller System Design and Control S YS-APM001 -EN Application Considerations Ener gy and economic analysis of alt er natives The process of making decisi ons between multiple, com peting alte rnatives is simplified with the assist ance of simulation sof tware.
SYS-APM00 1 -EN Chiller System Design and Control 27 Sy s te m D e s i g n O p t i o n s There are many c hilled-water -system design options; however , in a basic sense, eac h option is a function o f fl ow, temperature, system configuration, and control.
28 Chiller System Design and Control S YS-APM001 -EN S ystem Design Options recommends a design metho d that star ts with condenser -wat er temperat ure difference of 1 2°F to 18°F [7°C to 1 0°C].
S ystem Design Options SYS-APM00 1 -EN Chiller System Design and Control 29 Condenser -W at er T emper atur es T oday’ s c hillers can run at various en tering condenser -wa ter temperatures, from design temperature to the lowe st-allow able temperature for that par ticular c hiller design.
30 Chiller System Design and Control S YS-APM001 -EN S ystem Design Options Selecting flow r ates Designers may use the standard rating conditions to compare manufacturer s’ performances at exactl y the sam e conditions. However , these standards allow any flow rates to be used and certified comparisons to be made at a wider range of conditions.
S ystem Design Options SYS-APM00 1 -EN Chiller System Design and Control 31 1 .90 power , respecti vely . The examples here use the more conservati ve 1 .
32 Chiller System Design and Control S YS-APM001 -EN S ystem Design Options The total system powe r is now as foll ows: * Lo w -flow conditions represe nted in T able 5 through T able 8 are 1 .5 gpm/ton [0.0 27 L/s/kW] c hilled water and 2.0 gpm/ton [0.
S ystem Design Options SYS-APM00 1 -EN Chiller System Design and Control 33 Figure 21. Chilled water system performance at part load While the magnitud e of the benefit of low -flow c hanges depends o.
34 Chiller System Design and Control S YS-APM001 -EN S ystem Design Options performance of this coi l when it is selected with a 44°F [6.7°C] entering fluid temperature and a 1 0°F [5.6°C ] fluid temper ature rise ( T). T o provide the required 525 MBh [1 54 kW] of cooling capa city , the coil require s 1 05 gpm [6.
S ystem Design Options SYS-APM00 1 -EN Chiller System Design and Control 35 Q = U x A 1 x T 1 , where A = area, U = coefficient of heat transfer , and T = temperature difference so, for a roug.
36 Chiller System Design and Control S YS-APM001 -EN S ystem Design Options Same to w er , lar ger c hiller One retrofit option that benefi ts many building owners is instal ling a new, larger c hiller selected for a lower flow rating an d re-using the existing coolin g tower , condenser -wa ter pu mp, and condenser -water pi pes.
S ystem Design Options SYS-APM00 1 -EN Chiller System Design and Control 37 It quic kly becomes ev iden t that the same cooling towe r and flow rat e are adequate to re ject more heat—in this case, a pproxim ately 50 p ercent more heat.
38 Chiller System Design and Control S YS-APM001 -EN S ystem Design Options In both cases, either reusin g an exist ing tower , or reusing exi sting c hil led water pi ping, the design engineer can of ten help reduce total proj ect costs using the existing infrastructure by sel ecting a c hiller with a higher temperature differential.
S ystem Design Options SYS-APM00 1 -EN Chiller System Design and Control 39 Figure 23. Annual system operating costs (absorption chillers) Ke lly and Chan 10 compare the operational cost s of c hilled-water system designs in site locations. Their summary states: In conclusion, there are times you can ’have your cake and eat it too.
40 Chiller System Design and Control S YS-APM001 -EN S ystem Design Options and a more conservative zero condense r -water -pipe pressure drop, we c an examine the effect of reducin g flow rates.
S ystem Design Options SYS-APM00 1 -EN Chiller System Design and Control 41 Misconception 2—Low flo w only wor ks for specific manuf actur ers’ chillers. Demirc hian and Marag areci 12 , Eley 13 , and Sc hwedler and Nordeen 11 independently showed that system energy consum ption can be reduced b y reducing flow rates.
42 Chiller System Design and Control S YS-APM001 -EN S y st em Configurations Multiple c hilled-w ater systems are more common than sing le c hilled-water systems for the same reason that most commercial airplanes have more than one engine—th e balance of reliab ilit y and cost.
S ystem Configur ations SYS-APM00 1 -EN Chiller System Design and Control 43 Alternatively , the operating c hiller ca n be reset to produ ce a lower supply temperature at this co ndition. In this way , the mixed system supply-w ater temperature may be maintained at a more acceptable tempe rature.
44 Chiller System Design and Control S YS-APM001 -EN S ystem Configur ations Ser ies Chillers If c hillers are piped in series, as in Figure 27, the mixing problem disappear s and the starving coils problem (when one of the pumps in a par allel arrangem ent is not running) is resolved.
S ystem Configur ations SYS-APM00 1 -EN Chiller System Design and Control 45 percent of the system load. At system loads greater than 50 percent, the upstream c hiller is preferential ly loaded because it will attempt to produce the design leaving c hilled-water temper ature.
46 Chiller System Design and Control S YS-APM001 -EN S ystem Configur ations Figure 28. Decoup led arrangement The unrestricted bypass line hydraulica lly decouples, or separates, the production a nd distribution pumps so that they cannot operate in a series coupled pumping ar rangement.
S ystem Configur ations SYS-APM00 1 -EN Chiller System Design and Control 47 Pr oduction An individual production (c hiller) pump need only pump w ater from the return bypass tee (point A in F igure 29), through it s c hiller , and into the tee at the supply-end of the bypass line (point B in Figure 29).
48 Chiller System Design and Control S YS-APM001 -EN S ystem Configur ations Distr ibution Distribution pumps take water from the su pply water tee (point B in Figure 29), p ush it through all the d istribution piping and load terminal s, and then on to the return water tee (poin t A in Figure 29).
S ystem Configur ations SYS-APM00 1 -EN Chiller System Design and Control 49 Elev ated r etur n-wat er temper atur es. Because unused c hilled water does no t bypass the cooling coils (two-way , rather than three-wa y , co ntrol valves), all water that is returned a ccomplishes some c ooling.
50 Chiller System Design and Control S YS-APM001 -EN S ystem Configur ations Figure 33. Tertiary pumping arrangement Decoupled system–pr inc iple o f operation At the tee connecting th e supply and bypass lines, a supply–demand relationship exists, as shown in Figure 34.
S ystem Configur ations SYS-APM00 1 -EN Chiller System Design and Control 51 show a deficit an d the pump will be cy cled on again. The amount of surplus flow necessary depends o n th e size of the c hiller to be shut of f . The surplus flow must exceed a certain quantity befo re shuttin g off a c hiller–pump p air .
52 Chiller System Design and Control S YS-APM001 -EN S ystem Configur ations Chiller sequencing in decoupled systems Give n the amount and directi on of flow in the bypass line , c hill ers can be added or subtracte d.
S ystem Configur ations SYS-APM00 1 -EN Chiller System Design and Control 53 Figure 36. Double-ended decoupled system One of the benefits o f decoupled w ater systems is that they are simple to control. The distr ibution pump flow is determ ined by a pressure transducer located at the fur thest load.
54 Chiller System Design and Control S YS-APM001 -EN S ystem Configur ations When more than o ne c hiller plant is operating, finding the right location for the differential pressure sensor ca n be dif ficult. The poi nt of lowest pressure in the system sh if ts depending on which loads are using the most water .
S ystem Configur ations SYS-APM00 1 -EN Chiller System Design and Control 55 with a surplus th at may , o r may not, be large en ough to indicate stopping a c hiller in that plant. Other plant designs There are many other ways to connect c hillers to distributed loo ps and eac h provid es its own c hallenges and oppor tunities.
56 Chiller System Design and Control S YS-APM001 -EN S ystem Configur ations • The bypass can be positi oned either upstream or downstream o f the cooling coils. • A control valve in the b ypass ensures that the am ount of flow throug h the operating c hiller(s) never falls below the minim um limit, but remains closed most of the time.
S ystem Configur ations SYS-APM00 1 -EN Chiller System Design and Control 57 secondary systems. The pressure drops previou sly satisfied by the distribution pumps are instead satisfied by the now larg.
58 Chiller System Design and Control S YS-APM001 -EN S ystem Configur ations Experience with actual VPF plants in dicates that a minimum evaporator -flow limit of 60 per cent for pac kaged c hiller s and 40 percent or less for configured c hiller s work well.
S ystem Configur ations SYS-APM00 1 -EN Chiller System Design and Control 59 Small pac kaged c hillers typically of fe r less design fl exibility than larg er mac hines.
60 Chiller System Design and Control S YS-APM001 -EN S ystem Configur ations rate c hanges (T able 1 4 ). S electing c hille rs with these c harac teristics improves the likelihood of stable, u ninterr upted operation. Estimate the expected flow-rate c h anges and make sure that the c hillers you select can adapt to them .
S ystem Configur ations SYS-APM00 1 -EN Chiller System Design and Control 61 evaporator because its selectio n pressure drop is lower than that of Chiller 2.
62 Chiller System Design and Control S YS-APM001 -EN S ystem Configur ations Accur ate flo w measurement The success of a variable-primary-flow in stallation depend s on the quality of the flow-measuring device that controls the system bypass valve (and perhaps also indicates the plant load).
S ystem Configur ations SYS-APM00 1 -EN Chiller System Design and Control 63 • Locate a bypass line and valve near th e end of the pipin g run. The bypass control valve sees a lower operating pressure and may provide more stable control.
64 Chiller System Design and Control S YS-APM001 -EN S ystem Configur ations flow nears the maximum limit for the operating c hiller(s), another mac hine must be brought o nline. Similarl y , as the sy stem load and flow decrease, c hiller s must be shut down to re duce the need for bypass w ater flow.
S ystem Configur ations SYS-APM00 1 -EN Chiller System Design and Control 65 Contr olling tran sient flows is mand at ory , reg a rdless of plant size.
66 Chiller System Design and Control S YS-APM001 -EN S ystem Configur ations A more conservative approac h might be to wait to turn of f the c hiller until it would result in no higher than 80 percent capacit y for the remaining operating c hillers.
S ystem Configur ations SYS-APM00 1 -EN Chiller System Design and Control 67 Plant configuration Consider a ser ies ar ra ngement f or small VPF applications. When the plant c onsists of only two c hillers and expansion is un likely , you can simplify control by pi ping the evaporator s in seri es.
68 Chiller System Design and Control S YS-APM001 -EN S ystem Configur ations Figure 39. Example of operating-cost sa vings for a VPF, single-chiller plant Analysis results are based on a 50-ton scroll chiller and a 5-hp chilled water pump for two-story office bui lding in St.
S ystem Configur ations SYS-APM00 1 -EN Chiller System Design and Control 69 • Understand the specific loading/unloading c haracteristics of the c hiller controller Bypass flow • Select a high-qua.
70 Chiller System Design and Control S YS-APM001 -EN Chilled-W at er Syst em V ar iations A number of c hilled-water system variations can and should be used when appropriat e. Eac h con figuration offer s specific advantage s to solve problems and add value to the system.
Chilled-W at er Syst em V ar iations SYS-APM00 1 -EN Chiller System Design and Control 71 load. The details of operation are di scussed in “Sidestream plate-and-fra me heat exc hanger” on page 7 4.
72 Chiller System Design and Control S YS-APM001 -EN Chilled-W at er Syst em V ar iations One option is to equip one or more parallel c hillers with the refrigerant migration cycle (Figure 43) . This essentially turns the c hiller into a shell-and- tube heat exc hanger run-around loop.
Chilled-W at er Syst em V ar iations SYS-APM00 1 -EN Chiller System Design and Control 73 body of water . Flow rates need to be carefully select ed to balance the economic and en vironm ental re quirements.
74 Chiller System Design and Control S YS-APM001 -EN Chilled-W at er Syst em V ar iations One caveat when applying this arrangemen t is that c h illers on the producti on side of the bypass line will run more often at low par t-load conditio ns. Older c hil lers or newer c hiller s with a high cycle point may not have this capabil ity .
Chilled-W at er Syst em V ar iations SYS-APM00 1 -EN Chiller System Design and Control 75 Sidestream heat r ecovery A similar situation occu r s if a heat-reco very c hiller is placed in this sidestream position 24 (see Figure 46).
76 Chiller System Design and Control S YS-APM001 -EN Chilled-W at er Syst em V ar iations Sidestr eam system contr o l The flexibility of sidestream applicatio ns is increased by th e fact that the devices are used to pre-coo l return wa ter , not to produce the system c hilled- water temperature.
Chilled-W at er Syst em V ar iations SYS-APM00 1 -EN Chiller System Design and Control 77 Ser ies–Count erflo w Application Another system configuration that can be very energy efficient incorporates the previously descri bed series applicat io n, but does so fo r both the c hilled wat er and condenser water .
78 Chiller System Design and Control S YS-APM001 -EN Chilled-W at er Syst em V ar iations series. The lef t half of Figure 50 shows a modularized configuration where series c hiller modules are placed.
SYS-APM00 1 -EN Chiller System Design and Control 79 S ystem Issues and Challeng es Lo w T S yndr ome For man y years the “low T sy ndrome” debate has raged. 27, 28 The symptom of the problem is that, in large systems, return-w ater temperature is too low, thus not allowi ng the c hillers to fully load.
80 Chiller System Design and Control S YS-APM001 -EN S ystem Issues and Challeng es • Flow R ate = the system f low rate, in gpm [L/s] • Loop Time = the time it takes for flui d to leave the c hil.
S ystem Issues and Challeng es SYS-APM00 1 -EN Chiller System Design and Control 81 Conting ency T oday , many organizations have contin ge ncy plans for critic al area s of their business. Some deal with natural disasters and others with the loss of power in critical areas.
82 Chiller System Design and Control S YS-APM001 -EN S ystem Issues and Challeng es Location of equipment Location can be a major factor in co ntingency pl anning.
S ystem Issues and Challeng es SYS-APM00 1 -EN Chiller System Design and Control 83 situation. Electric al generation ca n be outsourced to avoid internal capitalization. A variation of electrical generation us es an engine indirectly - or directly- coupled to a c hiller .
84 Chiller System Design and Control S YS-APM001 -EN S ystem Issues and Challeng es Retr ofit Opport unities A tremendous retrofit oppor tunity can be realized i f the low -flow concepts discussed in the c hapter “System Design Options” on page 27 are ut ilized.
S ystem Issues and Challeng es SYS-APM00 1 -EN Chiller System Design and Control 85 T emperatur es out of rang e A laboratory load requires 120 gpm [7 .6 L/s] of water entering the process at 85°F [29.4°C] and returning at 95°F [3 5°C]. The accuracy required is more precise than the cooling tower can provid e.
86 Chiller System Design and Control S YS-APM001 -EN S ystem Issues and Challeng es Figure 53. P recise temperature control, multiple chillers Process Load Va r i a b l e - S p e e d Pump Chiller 2 Ch.
SYS-APM00 1 -EN Chiller System Design and Control 87 S ystem Contr ols Chilled-W ater S ystem Contr ol Chilled wat er reset—r a ising and lo wer ing Many c hilled-water plants use c hilled w ater reset, that is, the c hiller ’ s leaving- water temperature setpoint, in an ef fort to reduce c hiller energy consumption .
88 Chiller System Design and Control S YS-APM001 -EN S ystem Contr ols high. The control po int is selected to minimize over -pressu rizing the system and to assure adequate flow at all critical load s. Cr itical v alve r eset (pump pr essure optimization) Oft en, pumps are c ontrolled to maintain a constant-pressure dif ferential at a remote coil.
S ystem Contr ols SYS-APM00 1 -EN Chiller System Design and Control 89 If the c hiller and tower capa bilities are conduci ve to th is strateg y , the location and load profile d etermine if, wh en, and for how lo ng the right cond itions might occur .
90 Chiller System Design and Control S YS-APM001 -EN S ystem Contr ols The flow reduction opti ons include: • Cooling tower bypass • Chiller bypass • One or two thrott ling valves in the condens.
S ystem Contr ols SYS-APM00 1 -EN Chiller System Design and Control 91 prevalent than either two-speed fans or pony motors. Using variable-speed driv es on cooling-tower fans offers tw o distinct benefits. First, the tower - water -temperature control is extre mely good.
92 Chiller System Design and Control S YS-APM001 -EN S ystem Contr ols Var iable condenser wat er flow Chiller -t ow er -pum p balance There are times when a system design er may c hoose to vary the condenser water flow in addition to, or instead of, the coo ling- tower fan speed.
S ystem Contr ols SYS-APM00 1 -EN Chiller System Design and Control 93 These three energy consumer s must be balanced to minimize overall energy use. This mak es varying condenser wa ter flow complex, but the strategy below has been implemented o n projects.
94 Chiller System Design and Control S YS-APM001 -EN S ystem Contr ols separate wetting (recircu lation) pump provides a constant flow of w ater through the tower .
S ystem Contr ols SYS-APM00 1 -EN Chiller System Design and Control 95 F ailur e Recov ery With all the varied approa c hes available to potential customers, it sometim es seems that the main idea ge ts lost. People purchase c hilled-water plants to reliably produce c hilled w ater to satisf y another need, suc h as comfort or process cooling.
96 Chiller System Design and Control S YS-APM001 -EN Conclusion It is vital to have a cl ear understandin g of c hilled-water system concepts and their application. There is not hing parti cularly complex about the principles inv olved. Instead, sys tem design is simply a mat ter of exercising a few key rules of applied physics.
SYS-APM00 1 -EN Chiller System Design and Control 97 Glossary ASHRAE. American S ociety of Heating, Re frigerating, a nd Air -Conditioning Engineers (www.ashrae.org). building aut omation system (BAS). A cent ralized control and monitoring system for a building.
98 Chiller System Design and Control S YS-APM001 -EN Glossary COP . Coef ficient of P erformance; coo ling ef fect divided by heat input (dimensionless); the reci procal of ef ficiency . direct digital control. Program ming used by build ing control systems to control variable outputs, su c h as valves or actuators.
Glossary SYS-APM00 1 -EN Chiller System Design and Control 99 temper atur e, am bient. The tempera ture of the ai r surrounding the object under consid eration.
10 0 Chiller System Design and Control S YS-APM001 -EN Ref er ences 1 W ebb, R.L. and W . Li. “Fouling in Enh anced T ubes Using Coolin g T ower W ater , P art I: Long-T erm Fouling Data. ” Internatio nal Journal of Heat and Mass T ransfer 4 3, no.
Ref erences SYS-APM00 1 -EN Chiller System Design and Control 101 15 Bahnfleth, W . and E. Peyer . “Compa rative Ana lysis of V ariable and Constant Primary -Flow Chilled-W ater -Plant P erformance. ” HP AC Engineerin g (April 20 0 1). 16 Houghton, D.
10 2 Chiller System Design and Control SYS-APM00 1- EN Ref erences 32 T rane Applications Engineerin g Group. “Thermal Storage – Understanding the Choices. ” Ice Storage S ystems, Engineered Systems Clinics . T rane, 1 991 . ( ISS-CLC-2) 33 T rane Applications Engineerin g Group.
SYS-APM00 1 -EN Chiller System Design and Control 10 3 Index A absorption refriger ation 98 ASHRAE GreenGuide 27, 29, 33 Guideli ne 22 25 B bypass flow control 63 bypass lo cations 62 bypass valve 8 C.
10 4 Chiller System Design and Control SYS-APM00 1- EN Index controls chilled-water system control 87 condenser- water system con trol 89 direct-digital 24 managing control complexit y 21 programmable.
Index SYS-APM00 1 -EN Chiller System Design and Control 10 5 loads overview 7 low T syndro me 79 low flow cooling-tower options 34 misconceptions 39 M manifolded pumps 11, 14 mechanical-compressio.
10 6 Chiller System Design and Control SYS-APM00 1- EN Index standard ratin g flow conditions 29 standard rating temper atures 28 system configur ations 42 system control 87 system controls 87, 89 sys.
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Un punto importante, dopo l’acquisto del dispositivo (o anche prima di acquisto) è quello di leggere il manuale. Dobbiamo farlo per diversi motivi semplici:
Se non hai ancora comprato il Trane SYS-APM001-EN è un buon momento per familiarizzare con i dati di base del prodotto. Prime consultare le pagine iniziali del manuale d’uso, che si trova al di sopra. Dovresti trovare lì i dati tecnici più importanti del Trane SYS-APM001-EN - in questo modo è possibile verificare se l’apparecchio soddisfa le tue esigenze. Esplorando le pagine segenti del manuali d’uso Trane SYS-APM001-EN imparerai tutte le caratteristiche del prodotto e le informazioni sul suo funzionamento. Le informazioni sul Trane SYS-APM001-EN ti aiuteranno sicuramente a prendere una decisione relativa all’acquisto.
In una situazione in cui hai già il Trane SYS-APM001-EN, ma non hai ancora letto il manuale d’uso, dovresti farlo per le ragioni sopra descritte. Saprai quindi se hai correttamente usato le funzioni disponibili, e se hai commesso errori che possono ridurre la durata di vita del Trane SYS-APM001-EN.
Tuttavia, uno dei ruoli più importanti per l’utente svolti dal manuale d’uso è quello di aiutare a risolvere i problemi con il Trane SYS-APM001-EN. Quasi sempre, ci troverai Troubleshooting, cioè i guasti più frequenti e malfunzionamenti del dispositivo Trane SYS-APM001-EN insieme con le istruzioni su come risolverli. Anche se non si riesci a risolvere il problema, il manuale d’uso ti mostrerà il percorso di ulteriori procedimenti – il contatto con il centro servizio clienti o il servizio più vicino.
