Transcription
Chilled Water Plant Assessment& Criteria DesignPrepared for:ClevelandAirport SystemNovember 14, 2016PREPARED BY:1100 Superior AvenueCleveland, Ohio 44114(216)681-2020
Cleveland Hopkins International AirportMain Terminal Chiller Plant StudyNovember 14, 2016TABLE OF CONTENTSSECTIONPAGEExecutive Summary. 1Study Scope of Work . 2Overview . 3Existing Conditions . 4Evaluation . 7Recommendations & Design Criteria . 9Operating and Maintenance Savings . 10Probable Construction Cost Estimate . 12TOC
Cleveland Hopkins International AirportMain Terminal Chiller Plant StudyNovember 14, 2016Executive SummaryOsborn Engineering Company was requested by Delta Airport Consultants and Cleveland Airport Systemto evaluate the condition and remaining useful service life of the central cooling plant.Although the central cooling plant equipment and controls have been well maintained, the original (1978)chillers and pumps are well beyond their expected useful service life of 23 years (2001). The chillers added(1999 and 2001) after the initial building construction/renovation are also nearing the end of their servicelife. The overall estimated construction and project costs for the first phase system replacement is 5,300,000. The overall project cost includes the following soft costs: 10% for Profit; 10% for GeneralConditions; 10% for Design Contingency; 10% for Construction Contingency; 7% for Engineering Fees; 5%for Construction Manager and 1.5% for Commissioning. We allowed for 2 years to allocate funding andcomplete design documents for the plant replacement when calculating construction cost escalation.Average energy savings are estimated to be approximately 100,000 per year for the new central plant.After our interviews with the CHIA engineering and maintenance staff and analysis of the age andcondition of the plant equipment, it became evident that the best course of action would be a completechiller plant replacement undertaken as a two-phase project over several years. One chiller, the 750nominal ton Trane centrifugal chiller tagged CH-2 was deemed to be usable and would be retained for usefor the near future. In Phase 1 of the project we recommend replacement of the balance of the chillers,pumps and cooling towers comprising the chilled water plant. Existing CH-2 would remain in place andbe incorporated into the new plant to operate as one of three total chillers and be replaced later in Phase2 when it’s useful life ends. This would provide an N 1 configuration where two of the three chillerswould be capable of satisfying the current peak chilled water demand and a third chiller would be availableas redundant back up.Phase 1We recommend the following scope for the replacement: Replace (3) existing chillers (chillers currently identified as CH-1, CH-3 and CH-4) with (2)new 750 nominal ton centrifugal water cooled chillers.Replace seven (7) primary chilled and eight (8) condenser water pumps with new.Replace (6) existing cooling towers with (6) new all stainless steel / non-ferrousconstruction crossflow 475 nominal ton cooling towers.Replace and reconfigure the bulk of the chilled water supply and return piping comprisingthe chilled water plant.Replace two (2) approximately 2000 gpm variable speed secondary chilled water pumps.Maintain existing CH-2 (the existing Trane 750 ton chiller) for re-use during Phase 1.Upgrade / replace control devices (flow meters, control valves, sensors) associated withthe chilled water plant with new BACnet compatible devices and tie into the existingSiemens Apogee Building Automation System.Phase 2Replace existing chiller #2 in 5 to 8 years (planned) or sooner if any significant refrigerant / oil relatedproblems develop.Page 1 of 15
Cleveland Hopkins International AirportMain Terminal Chiller Plant StudyNovember 14, 2016Study Scope of WorkOsborn Engineering Company was requested to evaluate the condition and remaining useful service lifeof the central chilled water plant. The scope of work included: Field verification of the chiller and condenser water piping systems to generate an accurate flowdiagram of the existing configuration of each. This will identify location and sizes of existingpumps, valves, strainers and other key system components.Development of a plan and direction for the detailed chilled water plant design includingrecommendations for refrigerant utilized by the new plant equipment.Determination of system configuration and overall preliminary system capacity. (Final systemcapacity to be determined during the future detailed design portion of this project when adetailed analysis of run data and load calculations can be performed.)Visual inspection and recommendations for structural improvements/modifications necessaryduring the replacement of the cooling towers.Preparation of Design Criteria for owner’s use to procure the design services for the detaileddesign and REVIT modeling of construction documents for the replacement of the Chilled WaterPlant for the Main Terminal at Hopkins International Airport.This report is based upon our review of the existing available drawings of the mechanical systems andinspection of the facilities including identified mechanical equipment. The inspection services werelimited to a visual survey of existing conditions and exclude both non-destructive and destructive testing.This type of inspection does not clearly reveal all defects and requires certain engineering assumptions bemade to establish condition. These assumptions cannot always be verified without extensive testing,some of which can be destructive. Therefore, this report is not to be considered a guarantee of the exactcondition, life and total extent of potential repairs of the facilities inspected.Osborn Engineering does not have control over the cost of labor, materials, or equipment, or Contractor’smethods of determining prices, or over competitive bidding, market, or negotiating conditions.Accordingly, Osborn Engineering does not warrant or represent that bids or negotiated prices will not varyfrom any estimate or evaluation prepared, or agreed to, by Osborn Engineering.Page 2 of 15
Cleveland Hopkins International AirportMain Terminal Chiller Plant StudyNovember 14, 2016OverviewCleveland Hopkins International Airport (CLE) is located just 12 miles southwest of downtown Clevelandand is currently Ohio’s busiest airport, serving more than 9 million passengers annually. CLE was thenation’s first municipal airport when it initially opened in 1925, and has a long history of leadership sinclude the world’s firstradio-equippedairtraffic control tower andthe nation’s first airfieldlighting system. CLEwas also the first airportin the nation to have arail connection (addedin 1968) to allowtravelerstotakecommuter rail to/fromthe airport.Today, CLE has two parallel runways at 10,000 and 9,000 feet in length as well as a 6,000 foot crosswindrunway. It is the 32nd busiest airport in total flights and 43rd busiest in number of passengers in the nation,handling approximately 200,000 take-offs and landings annually. It covers approximately 1402 acres andincludes the main terminal and four concourses (A thru D). Concourse A was the first of the airport’soriginal two concourses and was built in 1962, with a major renovation in 1978. Concourse B was built in1966 and underwent renovations in 1982. Concourse C was added in 1968 and renovated in 1992. Finally,concourse D was added in 1999 to complete the airport’s current configuration.The Central Chilled Water Plant, that is the subject of this study, is located in the main penthouse levelmechanical room above the mainterminal area of the Airport. Thisis a critical building system for thefunction of airport activities as itproduces all the mechanicalcooling for the main terminalincluding all ticketing/check-in,baggage claim areas, food courtand Concourses A and B.Page 3 of 15
Cleveland Hopkins International AirportMain Terminal Chiller Plant StudyNovember 14, 2016Existing ConditionsThe Central Chilled Water Plant as it is currently configured, consists of three water-cooled centrifugalchillers and one water-cooled rotary (screw) chiller. Their nominal capacities are 750 (CH-2), 500 (CH-3),500 (CH-4) and 250(CH-1)tonsrespectively givingthe total plant anominal capacity of2000 tons.Heatrejection for thechillers is provided bysixindividualcrossflow, induceddraft cooling towersnominally sized at400 tons each. Thisarrangementprovides for a level of Figure 1: CH-3 and 1 (from left to right)redundancy and atotal of 2,400 connected tons of heat rejection. The current chilled water plant was initially installedduring the 1978 renovations to the main terminal and initially consisted of the two 500 ton chillers andthe cooling towers as listed above. The chilled and condenser water piping system has been modifiedseveral times in the past, most notably with the addition of the 750 ton chiller in approximately 2001. The250 ton chiller was initially installed during 1999 as part of a baggage handling expansion project forContinental Airlines and was not initially part of the central chilled water plant. The piping and buildingautomation system was modified about two years ago to tie this chiller into the central plant system toallow it to help carry the cooling loads. Documentation for all of these system modifications wasincomplete or unable to be located. Therefore, as part of this study, Osborn Engineering created a oneline flow schematic of the Central Chilled Water Plant piping and equipment that is provided for referencelater in this report.The condenser water piping system is made upof eight condenser water pumps and sixindividual cooling towers that are roughlyconfigured into a North and South side thatnearly mirror each other. Each “side” is madeup of three cooling towers and four pumpspiped together in a common header (threepumps run paired with a cooling tower and thefourth serves as redundant back-up). Each sideties together into a common header that feedswater to all the chillers. In practice it is Figure 2: South Condenser Water PumpsPage 4 of 15
Cleveland Hopkins International AirportMain Terminal Chiller Plant StudyNovember 14, 2016operated so that the South cooling towers operate in conjunction with CH-1, 3 and 4 and the North coolingtowers operate with CH-2.The chilled water piping is currentlyconfigured in a very non-traditional layout.The largest chiller is currently identified as CH2 and is the 750 ton Trane chiller that wasinstalled in about 2001. There are two chilledwater pumps configured lead-lag (tagged P-11& P-12) that draw water thru this chiller andpump it into a chilled water supply pipeheader that feeds to the suction side of thesystem load pumps (P-16 & P-17). Commonindustry practice is to pump water through Figure 3: Pumps P-11 and P-12 serve CH-2chillers not draw the water through them. (The pumps add a small amount of heat to the chilled water)The two 500 nominal ton chillers (CH-3 and CH-4 installed in 1978) are served by a three pump package(P-13, 14 & 15) that is configured so that P-13is paired with one chiller and P-15 with theother. P-14 is on a common header with theother two and serves as back-up for eitherchiller. These chillers and pumps are alsopiped so the water is drawn through thechillers and then flows in series to the suctionof pumps P-16 and P-17. CH-3 is currentlybeing repaired from damage suffered duringlast winter. The condenser water barrel frozeFigure 3: Pumps P-13, P-14 and P-15and damaged the tubes. Fortunately, therefrigeration system was not affected by this freeze. The last chiller (CH-1, the 250 nominal ton screwmachine) was added into the system a few years ago and is piped to draw water out of the chilled waterreturn header and pump it through chiller 1. Itis served by two chilled water pumps inlead/lag configuration and this chiller also hasits own lead/lag condenser water pumps.There are also a number of control valves andbypass connections in the chilled water supplyand return lines serving this chiller. Lastly, thischiller has its pumps pushing the waterthrough the evaporator barrel, not drawing itthrough the chiller as all the other chillers areconfigured. Chiller #1 is also currently being Figure 5: CH-1 and its Pumpsrepaired from damage suffered last winter when its condenser barrel froze and damaged the barrel, tubesand refrigeration system.Record drawings for the system are incomplete/inaccurate and some modifications to the system havebeen made where the design and as-built documents are no longer available.Page 5 of 15
Cleveland Hopkins International AirportMain Terminal Chiller Plant StudyNovember 14, 2016The chilled water plant is controlled by a Siemens Apogee Building Automation System (BAS). The headend and system interface have been upgraded over the years and are up-to-date and capable ofcontrolling a new chilled water plant. The existing sensors, flow meters, control valves and other controldeviceshavebeen in servicesince their initialinstallation andinneedofreplacement.The BAS utilizes agraphicaluserinterfacethatindicates systemset-points,temperatures,flow informationand equipmentrun status andalarms. This userinterface couldbe modified to be Figure 6: Control System interface for chillers.utilized in a similar, familiar format to control and operate a modified chilled water plant.Figure 7: Control System interface for North Cooling Towers and condenser pumps.Page 6 of 15
Cleveland Hopkins International AirportMain Terminal Chiller Plant StudyNovember 14, 2016EvaluationThe majority of the equipment making up the main chilled water plant is significantly past the median lifeexpectancy as predicted by ASHRAE. The median life expectancy for centrifugal water cooled chillers is23 years. Chiller #2 (the 750 ton machine) is serving in its 15th year, chillers #3 and #4 (the two 500nominal ton machines) are in their 38th year of operation and chiller #1 (the 250 ton machine originallyinstalled in 1999) is in its 17th year of operation. The condenser water pumps and the chilled water pumpsserving CH-3 and 4 all appear to be original from 1978. The chilled water pumps serving CH-2 appear tohave been installed in conjunction with the installation of that chiller and the chilled water and condenserwater pumps serving CH-1 were installed with that chiller in 1999. The cooling towers appear to havebeen replaced or at minimum have had the fill replaced at some point in the past. They are all showingsigns that at a minimum the fill is in need of replacement, the hot water basins are leaking and havepreviously been identified as needing to be replaced or have a major refurbishment performed. ASHRAEindicates the median lifeexpectancy for coolingtowersandbasemounted pumps to be20 years. (See Table 1)For the chillers, there isanotherimportantfactor to consider.Federal Law regulatesthe production and useof refrigerants utilizedby HVAC equipment toprevent greenhouse gasemissions and limitGlobal Warming. Thefour existing chillersutilize three differentrefrigerants. One of thetwo oldest chillers (thetwo 500 ton machines)still utilizes R-11 and theother was refitted atsome point in the past tooperate on R-123 (whenTable 1: ASHRAE Equipment Life Expectancy Chartinitiallyinstalleditoperated on R-11). R-11 is a refrigerant that is no longer available and was phased out of production in2010. It is likely that there was a repair required for this chiller in the past where the scarcity and cost ofR-11 made it a better option to convert the machine to use R-123 instead. One problem with this solutionis that the chiller is de-rated by approximately 10% (chiller peak capacity is reduced from 500 tons in thiscase to about 450 tons) by this conversion to an alternate refrigerant. The newest chiller (the 750 tonPage 7 of 15
Cleveland Hopkins International AirportMain Terminal Chiller Plant StudyNovember 14, 2016model) uses R-123 and the smaller 250 ton machine uses R-22.R-123 and R-22 are both HCFC(Hydrochlorofluorocarbon) refrigerants that by EPA regulation are to be phased out in 2020. At that point,manufacturers will no longer be able to manufacture new refrigerant and must use only recycledrefrigerant to maintain operation of equipment already in use. Also beginning in 2020, no newrefrigeration equipment can be manufactured or sold using either R-123 or R-22. In advance of the phaseout, chiller manufacturers have already begun changing refrigerants utilized to more environmentallyfriendly options. Additionally, the cost of R-22 and R-123 has already begun to increase substantially overthe past few years. Using the past as a guide with the CFC (Chlorofluorocarbon) refrigerants phased outin 2010, the cost of the next group being phased out in 2020 can be expected to increase dramatically inthe next few years. The Cooling Towers were noted by Gardiner Service (the Airport’s service vendor) ashaving leaking hot water basins and the fill is beginning to fail. They have already provided a proposal fora major cooling tower refurbishment and recommend this work be done in the near future.Reasons for a complete or phased replacement of the chiller plant include:Chillers CH-3 and CH-4, all the cooling towers and the associated pumps are well beyond theiruseful service life.CH-1 and CH-2, while still in running condition with life expectancy remaining, must beplanned for replacement due to their refrigerants. These units are beyond their mid-point ofoperational life so a simple refrigerant replacement to extend service life would not be costeffective. Maintenance costs typically accelerate during the last third of equipment’s usefullife, but costs for these machines will accelerate even faster due to the rising cost ofrefrigerant associated with the phase out of R-123 and R-22.The chilled water plant operated for all the summer of 2016 with 1250 nominal tons of coolingcarrying the building load (Chillers 2 and 4). Plant operations personnel indicated that on dayswhere the outside temperature met or exceeded 90oF, they would need to pre-cool thebuilding so the system could keep up with the load during the late afternoon hours. This is astrong indicator that the plant load is slightly above 1250 tons. For means of comparison,ASHRAE 1% cooling design conditions for Cleveland are 91oF dry bulb, 83oF wet bulb. For thispast summer with chillers 1 and 3 off-line undergoing repairs, the system operated with noredundancy in the event of an equipment failure.The existing plant equipment and control is not as energy efficient as new chillers withoptimized control. The plant efficiency is further degraded by the multiple pipingmodifications made over the years and the conversion of CH-3 from R-11 to R-123.The existing controllers, sensors and control valves are obsolete and in need of replacement.Page 8 of 15
Cleveland Hopkins International AirportMain Terminal Chiller Plant StudyNovember 14, 2016Recommendations & Design Criteria1. Replace chillers 1, 3 and 4. We recommend replacing these three chillers during phase 1 with twonew 600 to 750 ton oil-less bearing centrifugal chillers. Oil-less bearing chillers offer substantiallong term advantages over traditional oil lubricated machines through lower operation andmaintenance activities and costs, as well as higher operating efficiency at partial loads. Plannedreplacement should be anticipated in approximately 2 to 4 years. Maintain existing Chiller #2 foruse with the re-designed chiller plant and incorporate future connection points to allowreplacement of this machine when age, maintenance costs and/or scarcity of R-123 refrigerantdictates its replacement. Planned replacement of Chiller #2 (with a new chiller matching the twophase 1 chillers) should be anticipated in approximately 5 to 8 years.a. Engage a certified balance contractor to take water flow readings for each of the existingchillers and for the load side chilled water supply. Utilize load side flow data and systemtemperatures to finalize exact size of chillers to provide for N 1 chiller plant.b. Reconfigure piping to improve system efficiency and allow for primary / secondary chilledwater loops to be created with a hydraulic / air / dirt separator providing the bridgebetween the primary and secondary loops. For purposes of this study, we have notassessed the chilled water piping on the load side of the system beyond the supply sideof the secondary chilled water pumps. Further evaluation of the chilled water piping inthe space needs to be undertaken, as well as evaluation of the condition and remainingservice life of the load-side equipment (air handlers, fan coils).2. Perform a 3D laser scan of the mechanical room surrounding the system equipment and the roofarea around the cooling towers and generate a 3D Revit model for new chiller plant. Generatenew chiller plant design drawings in Revit and update model with as-built conditions atcompletion of the project. Turn this model over to Cleveland Airport System for incorporationinto the overall Airport Revit model that has been started on other projects recently completedat CHIA.3. Remove and replace the bulk of the chilled water piping and pumps in the mechanical room andcreate a primary / secondary arrangement in the chilled water piping to allow for greater controland plant efficiency. Provide new variable frequency drives (VFD) with all new pumps.4. Remove and replace the condenser water piping and pumps to optimize pumping energyefficiency with the new chillers. Provide VFD’s with all new pumps.5. Replace the cooling towers with new towers of the same physical size to allow installation ontothe existing structural steel with only minimal maintenance / repairs / modifications. Duringdetailed design, evaluate increasing fan size for the towers to allow for lower condenser watersupply temperatures to optimize chiller plant efficiency. Provide VFD’s for speed control for eachcooling tower. Remove paint from cooling tower structural steel, assess structure in detail andrepair/replace any members showing excess corrosion and paint structure with zinc-rich paint.6. Provide new flow and temperature sensors for each chiller and both the primary and secondarychilled water loops as well as the condenser water north and south piping loops. UpgradeSiemens BAS to efficiently control all aspects of the chiller plant operation including varyingnumber of chillers and cooling towers operating to match load conditions, varying primary chilledwater pump flow, cooling tower fan(s) / speed(s), condenser water system flow and systemtemperatures.Page 9 of 15
Cleveland Hopkins International AirportMain Terminal Chiller Plant StudyNovember 14, 2016Operating and Maintenance SavingsOperating CostsBASELINE - 4tons, peak chilled water demandEFLH, equivalent full load hourston-hours, estimated annual chilled water consumptionkW per ton, chiller average annual efficiencykW per ton, primary chilled water pump average annual efficiencykW per ton, secondary chilled water pump average annual efficiencykW per ton, cooling tower fan average annual efficiencykW per ton, condenser water pump average annual efficiencykW/ton, average annual plant1.29efficiency3,163,236kWh per year, average annual electricity consumption 0.060 /kWh, electricity rate - 2016 CEI 189,794 /year, average annual electricity ours, estimated annual chilled water consumptionkW per ton, chiller average annual efficiencykW per ton, primary chilled water pump average annual efficiencykW per ton, secondary chilled water pump average annual efficiencykW per ton, cooling tower fan average annual efficiencykW per ton, condenser water pump average annual efficiencykW/ton, average annual plant0.61efficiency1,487,050kWh per year, average annual electricity consumption 0.060 /kWh, electricity rate - 2016 CEI 89,223 /year, average annual electricity cost 100,571 /year, average annual electricity cost savingsPage 10 of 15
Cleveland Hopkins International AirportMain Terminal Chiller Plant StudyNovember 14, 2016Maintenance Costs (Comparison of OilOil-Less to Standard Centrifugal Chillers)Maintenance CostsYear1234567891011121314151617181920Oil-Less ChillersChillersAnnual MaintenancePM Outsource Total 8,125 8,125 8,125 8,125 16,250 8,125 8,125 16,250 8,125 8,125 16,250 8,125 8,125 16,250 8,875 15,531 24,406 8,875 15,531 24,406 8,875 15,531 24,406 8,875 15,531 24,406 8,875 15,531 24,406 10,500 26,250 36,750 10,500 26,250 36,750 10,500 26,250 36,750 10,500 26,250 36,750 10,500 26,250 36,750 14,400 46,800 61,200 14,400 46,800 61,200 14,400 46,800 61,200 14,400 46,800 61,200 14,400 46,800 61,200 209,500 475,406 684,906Standard ChillersChillersAnnual MaintenancePM Outsource Total 10,500 10,500 10,500 10,500 21,000 10,500 10,500 21,000 10,500 10,500 21,000 10,500 10,500 21,000 11,500 20,125 31,625 11,500 20,125 31,625 11,500 20,125 31,625 11,500 20,125 31,625 11,500 20,125 31,625 13,700 34,250 47,950 13,700 34,250 47,950 13,700 34,250 47,950 13,700 34,250 47,950 13,700 34,250 47,950 18,700 60,775 79,475 18,700 60,775 79,475 18,700 60,775 79,475 18,700 60,775 79,475 18,700 60,775 79,475 272,000 617,750 889,750 18,275)(204,844)The operating efficiency of oil-less (magnetic bearing in this example) chillers is better at part loadconditions than standard design chillers (Integrated Part Load Value of about .305kW/T compared to.343kW/T). Total plant annual energy savings anticipated based on 2016 electric rates:2,450,000 Ton Hours x (.343-.305 kW/Th) x 0.06 /KWH 5,586.00 savings per yearThe probable premium cost for oil-less over standard chillers is approximately 30,000. When operationalsavings is combined with anticipated maintenance savings, the simple payback of the premium cost wouldbe realized in less than four years. Note that in the event the electric rate increases, payback would berealized even sooner.Page 11 of 15
Cleveland Hopkins International AirportMain Terminal Chiller Plant StudyNovember 14, 2016Probable Construction Cost EstimateORIGINATING OFFICEOsborn EngineeringESTIMATEWORKSHEETDATE SUBMITTED10/17/16PROJECT AND CITYCleveland Hopkins International AirportChilled Water Plant Study & Criteria DesignCleveland, OhioESTIMATE VALID TO:06/30/17ESTIMATED BY:JHPLabor Rate: 75.00COST SUMMARY BY SHEETPiping DemolitionChilled Water PipingCondenser Water PipingNew Mechanical EquipmentGeneral TradesSubs (Electrical, Testing & Balance, BAS, Insulation, Rigging)SUBTOTAL 1PROFITSUBTOTAL 2GENERAL CONDITIONSSUBTOTAL 3ESCALATION TO MIDPOINT OF CONSTRUCTIONSUBTOTAL 4DESIGN CONTINGENCYSUBTOTAL 5 - ECCA (Estimated Construction Cost at Award)CONSTRUCTION CONTINGENCYSUBTOTAL 6 - ECC (Estimated Construction Cost)ENGINEERING FEESCONSTRUCTION MANAGERCOMMISSIONINGCONTRACT NO.STUDYPURPOSEOpinion of Probable Construction CostITEMSummary by SheetPSLCF1.15MATERIALPERUNITSUBTOTALDESCRIPTION OF WORKPROJECT NO.J20160465.000Chilled Water Plant Phase 80382,28333,750213,7802,061,685967,435 71,003370,875803,8741,300,67367,500415,195 3,029,120 302,912 3,332,032 333,203 3,665,235 183,262 3,848,497 384,850 4,233,347 ECCA 423,335 4,656,681 ECC 325,968 232,834 0%5.0%1.50%TOTAL PROJECT COST TOTAL PROJECT COST ROUNDED UP 99,231518,3171,123,4541,817,75594,335580,256 4,233,347 123,890647,1191,402,6322,269,467117,777724,449 5,285,333 4,300,000 4,700,000Page 12 of 15
Cleveland Hopkins International AirportMain Terminal Chiller Plant StudyNovember 14, 2016Page 13 of 15
Cleveland Hopkins International AirportMain Terminal Chiller Plant StudyNovember 14, 2016Page 14 of 15
Cleveland Hopkins International AirportMain Terminal Chiller Plant StudyNovember 14, 2016Page 15 of 15
installed in about 2001. There are two chilled water pumps configured lead-lag (tagged P-11 & P-12) that draw water thru this chiller and pump it into a chilled water supply pipe header that feeds to the suction side of the system load pumps (P-16 & P-17). Common industry practice is to pump water through
