1 Hospital Building and Campus Piping

2 Hospital Building Occupancy – office and patient areas Patient areas: 24 hours per day Office areas: 8 am – 5 pm, Monday - Friday Building Characteristics: Four story with basement 140,000 square feet per floor Standard construction

3 Hospital – Stand alone operation Larger building Larger pumps Similar applications

4 Medical Complex with Central Plant All buildings served from a single heating and cooling source located in a central plant Hot and chilled water are distributed to each building via piping loops

5 Medical Complex with Central Plant Similarities All previous examples can exist in the same or larger scale Differences Pumps may be larger Distribution piping can be different Location of central plant is critical Multiple central plants may be tied together

6 Campus Piping Systems

7 Types of Piping Systems Closed Loop Systems Chilled Water Systems Hot Water Systems Open Loop System Condenser Water Systems Domestic Hot Water Recirculation Domestic Pressure Boosting (future session)

8 Two Pipe Direct Return C H I L L E R C H I L L E R C H I L L E R Return Supply Pump Controller Secondary Pumps Primary Pumps Expansion Tank Air Separator Common Pipe

9 Two Pipe Direct Return Common applications Basis of design for most CHW systems. Small, medium, or large size buildings Low or high rise Single or multiple buildings Single supply temperature

10 Two Pipe Direct Return Piping Tips Common pipe design Tank Point of No Pressure Change (PNPC) Warmest water Air control and relief 2-way valves Size Location

11 Two Pipe Direct Return Advantages Simplicity First Cost Efficient Disadvantages Over-pressurization Balancing Head requirement Thermally linked

12 Primary-Secondary-Tertiary C H I L L E R C H I L L E R Zone A Zone B Zone C Optional Variable Speed Pump ∆P Sensor Modulating Control Valves Secondary Pump C H I L L E R Primary Pumps Tertiary Pumps Common Pipe Common Pipe

13 Primary-Secondary-Tertiary Common applications Multi-building campuses Campuses with large diversity Campuses with buildings of varying heights Campuses with long piping runs Campuses with multiple production plants Campuses with elevation changes

14 Tertiary Loop Piping T3 T1 Load MV Load MV Common Pipe T2 Tertiary Zone Pumps Tertiary Bridge Secondary Pump(s) Secondary Chilled Water Return Small Bypass Maintains Accurate Temperature Reading Magna3 MV

15 Primary-Secondary-Tertiary w/Plate HX Expansion Tank Air Separator Expansion Tank Air Separator C H I L L E R C H I L L E R Optional VS Pump ∆P Sensor Modulating Control Valves Secondary Pump C H I L L E R Primary Pumps Magna3 Common Pipe Plate HX Tertiary Pumps

16 Tertiary Loop Piping w/ Plate HX Small Bypass Maintains Accurate Temperature Reading T3 T1 Load MV Load MV T2 Tertiary Zone Pumps Tertiary Bridge Secondary Pump(s) Secondary Chilled Water Return Small Bypass Maintains Accurate Temperature Reading Magna3 T3 T1 Load MV Load MV Load MV T2 Tertiary Zone Pump Tertiary Bridge Secondary Pump(s) Secondary Chilled Water Return Magna3 MV Plate HX

17 Primary-Secondary-Tertiary Piping Tips When HX are used, additional tanks and air separator devices must be added to tertiary Controls for secondary and tertiary systems are independent

18 Primary-Secondary-Tertiary Advantages Hydraulic isolation Thermal isolation Horsepower reduction Operational cost savings System performance optimization Disadvantages Additional piping Additional control valves First cost Over-pressurization of near zones unless plate hx is used More pumps

19 Open Piped Systems Chiller Piping Condenser water piping Condenser water with economizer.

20 Condenser Water Piping Return Supply Tower Evaporator Condenser Primary Pump(s) Secondary Pump(s) Condenser Pump(s) Chiller Sediment Separator Expansion Tank And Air Separator

21 Condenser Water w/ Economizer Return Supply Tower Evaporator Condenser Primary Pump(s) Secondary Pump(s) Condenser Pump(s) Head Pressure Control Valve Heat Exchanger Loads Sediment Separator Expansion Tank And Air Separator

22 Condenser Water Piping Condenser Water Tips Installation Keep pump suction flooded Watch NPSH Operation Air pockets End of curve Maintenance Strainers Air vents

23 Best Practice Design

24 Best Practice Design Why Constant speed pump Variable speed pump Optimize Pump Impeller

Best Practice Design Why ‒ Equipment over-sizing ‒ Cost penalty ‒ Mandate Optimize Pump Impeller

26 Best Practice Design Constant speed pump Trim the impeller. Utilize the affinity laws. Follow the system curve. Save operating cost. First costs.

27 Variable speed pump Impeller optimization Follows affinity laws Does not correct for poor engineering Over-sized pumps minimize turndown ratio Over-sized pumps and motors operate at lower efficiencies No added first costs Best Practice Design

28 Primary Piping for Hot Water Systems Pump out of a boiler Keep the boiler at the lowest possible pressure Remember NPSH! Boiler 2 P1P2 Boiler 1 Best Practice Design

29 Primary Piping for Chilled Water Systems Pump into a chiller Largest pressure drops after the pump Chiller Primary Pumps Chiller Best Practice Design

30 System Bypass Options Return Supply Pump Controller Secondary CS Pump(s) Common Pipe Chiller 2Chiller 1Chiller 3 Best Practice Design

31 System Bypass Options Locate bypass near end of system Locate bypass near end of major loops Selectively leave 3-way valves Bypass with pressure activated control Variable speed considerations Best Practice Design

32 Effect at minimum VFD speed Below 30% speed: CS, but still VV % Flow Head 100 % Speed 30% Speed Best Practice Design

GPM Pump 1 Variable Speed: 100 Ft Pump 2 Constant Speed: Ft Wrong! Mixing CS and VS Pumps Best Practice Design

34 Sensor Location Return Supply Pump Controller VFDs ∆P∆P Sensor Chiller 3 Chiller 2Chiller 1 Primary Pumps Secondary Pumps Best Practice Design

35 Sensor Location The Traditional Way – Hydronically, the farthest load – Typically the largest, farthest load – Maximize the variable head loss – Multiple sensors are a benefit Best Practice Design

36 Optimized solution not only for the pumps, but for the total system conditions Uncontrolled (constant volume) curve Constant pressure Proportional pressure Temperature control FLOW ADAPT AUTO ADAPT Best Practice Design

37 Best Practice Design Q 100%25% H 1. Uncontrolled 2. Constant pressure 3. Proportional pressure (calculated) 4. Proportional pressure (measured) 5. Temperature control Flow in % Effect in % Get Additional Energy Savings

38 Best Practice Design - Demand More Total Efficiency vs. Control Modes

39 Best Practice Design - Demand More Comparison

Flow Limit FLOW LIMIT Potential saving compared to an unintelligent pump Potential saving compared with proportional pressure mode Duty point Additional saving with FLOW LIMIT Performance curve Intelligent Control – FLOW ADAPT /FLOW LIMIT Best Practice Design - Demand More 40

41 Best Practice Design - Demand More

42 UPDATE Q 100%25% H 1.Uncontrolled 2.Constant pressure 3.Proportional pressure (calculated) 4.Proportional pressure (measured) 5.Temperature control Flow in % Effect in % Best Practice Design – Demand More Intelligent Control - Overview

43 Best Practice Design - Demand More Drive Motor and Pump Effeciency

44 100% 80% 70% 60% 50% 25% 90% HRPM 0 Max. curve Control curve Pressure reduction DP1DP3DP4DP2 Control mode Best Practice Design – Demand More Intelligent Control - Pressure Control

45 100% 80% 70% 60% 50% 25% 90% HRPM 0 Max. curve Control curve Pressure reduction DP1DP3DP4DP2 Control mode Best Practice Design - Demand More Intelligent Control: Calculated Pressure Control

46 100% 80% 70% 60% 50% 25% 90% HRPM 0 Max. curve Control curve Pressure reduction DP1DP3DP4DP2 Control mode Best Practice Design - Demand More Intelligent Control: Measured Pressure Control

47 100% 80% 70% 60% 50% 25% 90% HRPM 0 Max. curve Control curve Pressure reduction DP1DP3DP4DP2 Control mode Best Practice Design - Demand More Intelligent Control: Temperature Control

48 Best Practice Design

49 Affinity Laws Capacity varies to the ratio of the diameter change Head varies to the ratio of the square of the diameter change Brake horsepower varies to the ratio of the cube of the diameter change Best Practice Design

50 Affinity Laws Best Practice Design

51 What Impacts the System Head? Actual component pressure drops Actual piping loses Present vs. future loads Safety Factors Heating vs. cooling flow Best Practice Design

52 What Happened if......you read a flow rate of 1425 gpm instead of the design 1150 gpm? Best Practice Design

” Impeller Curve Best Practice Design System Curve #1 System Curve #2

54 Throttle Valve Best Practice Design System Curve #1 System Curve #2

55 Best Practice Design HP Penalty? HP = Flow x Head x Specific Gravity/3960 x Pump Eff. Throttled Head = Design Head – Measured Head Throttled Head = 138 – 120 = 18 feet Throttled HP = 1150 x 18 x 1/3960 x 0.86 Wasted HP across balance valve? HP = 6.08

56 Correcting pump over-sizing: Close valve at pump Balance system Trim the impeller VFD Best Practice Design

57 10”inch Impeller Curve in System Curve #1 System Curve #2 Best Practice Design

58 Best Practice Design True HP Penalty HP = Flow x Head x Specific Gravity/3960 x Pump Eff. Head at actual point of operation = 80 feet Head savings = 138 – 80 = 58 feet, not 18 feet Wasted HP with untrimmed impeller… HP = 1150 x 58 x 1/3960 x 0.82 HP = 20.54! Trim impeller from 12.10” to 10.0”

59 Operating Cost Pump Motor Best Practice Design

60 Operating Cost: “Standard Efficiency” Motor = 90.9 BHP = (1150 x 138 x 1.0) / 3960 x 0.86 = kW = (34.47 x ) / = AOC = x 8760 x $0.10/kWh = $24,768 Best Practice Design

61 Operating Cost: “High Efficiency” Motor = 93.4 BHP = (1150 x 138 x 1.0) / 3960 x 0.86 = kW = (34.47 x ) / = AOC = x 8760 x $0.10/kWh = $24,108 Best Practice Design

62 Operating Cost Comparison: Motor change out $0.10/kWh Standard Efficiency$24,768 High Efficiency$24,108 Annual Savings$ 660 Best Practice Design

63 Trim the Impeller to 10”: Flow = 1150 gpm Head = 80 ft Pump efficiency = 0.82 Standard efficiency motor = 87.9 High efficiency motor = 90.3 Best Practice Design

64 Operating Cost: “Standard Efficiency” Motor = 87.9 BHP = (1150 x 80 x 1.0) / 3960 x 0.82 = kW = (28.33 x ) / = AOC = x 8760 x $0.10/kWh = $21,055 Best Practice Design

65 Operating Cost: “High Efficiency” Motor = 90.3 BHP = (1150 x 80 x 1.0) / 3960 x 0.82 = kW = (28.33 x ) / = AOC = x 8760 x $0.10/kWh = $20,494 Best Practice Design

66 Std EffHi Ft $24,768 $24, ft $21,055 $20,494 $561 Difference $ 3,713 $ 3,614 $4,274 Operating Cost Comparison: High Eff. Motor + Trimming Impeller Best Practice Design

67 Best Practice Design Impeller Trimming True cost to trim impeller Remove and replace impeller Replace seals Replace bearings Downtime Calculate payback

68 Best Practice Design Maximize impeller to non-overloading motor size. Impeller Trim Curves NOL HP