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chilled-water-system-presentation.pdf

  1. COMMERCIAL BUILDING SERVICES FLOW THINKING Chilled Water System Presentation
  2. COMMERCIAL BUILDING SERVICES FLOW THINKING Constant Volume Distribution Constant Volume Distribution
  3. COMMERCIAL BUILDING SERVICES FLOW THINKING Air-conditioning System Components
  4. COMMERCIAL BUILDING SERVICES FLOW THINKING Constant Volume System Components
  5. COMMERCIAL BUILDING SERVICES FLOW THINKING Typical 3-way Valve Zone
  6. COMMERCIAL BUILDING SERVICES FLOW THINKING Full Load Condition
  7. COMMERCIAL BUILDING SERVICES FLOW THINKING Fully Loaded Coil • Supply water temperature 45°F • Design return water temp. 55°F • Coil design flow 100 GPM • Coil design pressure drop 20 FT • Load (flow x 10°F∆ x 500) 500,000 Btuh • Coil ∆P @ design flow 20 FT • Bypass flow 0 GPM • Bypass ∆P 3-way valve closed • 3-way valve pressure drop 10 FT • Pump flow and head 100 GPM @ 30 FT • Actual return water temp 55 °F
  8. COMMERCIAL BUILDING SERVICES FLOW THINKING Unloaded Condition
  9. COMMERCIAL BUILDING SERVICES FLOW THINKING Unloaded Coil • Supply water temperature 45°F • Design return water temp. 55°F • Coil design flow 0 GPM • Coil design pressure drop 3-way valve closed • Load (flow x 10°F∆ x 500) 0.0 Btuh • Coil ∆P @ design flow 0 FT • Bypass flow 100 GPM • Bypass ∆P 20 FT • 3-way valve pressure drop 10 FT • Pump flow and head 100 GPM @ 30 FT • Actual return water temp 45 °F
  10. COMMERCIAL BUILDING SERVICES FLOW THINKING So What? • When the load on the coil is zero, the valve is returning “unused” chilled water at essentially supply temperature. • Cold return water “unloads” the chillers, causing them to operate inefficiently.
  11. COMMERCIAL BUILDING SERVICES FLOW THINKING Part Load Condition
  12. COMMERCIAL BUILDING SERVICES FLOW THINKING Partially Loaded Coil • Supply water temperature 45°F • Design return water temp. 55°F • Coil design flow 50 GPM • Coil design pressure drop 20 FT • Load (flow x 10°F∆ x 500) 250,000 Btuh • Coil ∆P @ design flow 5 FT • Bypass flow ??? GPM • Bypass ∆P 3-way partially closed • 3-way valve pressure drop 10 FT • Pump flow and head ??? GPM @ 30 FT • Actual return water temp ?? °F
  13. COMMERCIAL BUILDING SERVICES FLOW THINKING 125 100 75 50 25 0 % Valve Stroke 25 50 75 100 % Flow 1/2 Through Coil 1/2 Through Bypass Full Flow Through Coil Full Flow Through Bypass 3-way Valve Characteristic
  14. COMMERCIAL BUILDING SERVICES FLOW THINKING What’s Really Happening?
  15. COMMERCIAL BUILDING SERVICES FLOW THINKING Coil with 3-way Valve at Mid-position • Supply water temperature 45 °F • Design return water temp. 55 °F • Load (flow x 10°F∆ x 500) 250,000 Btuh • Coil design pressure drop 20 FT • Coil flow 62.5 GPM • Coil ∆P @ 62.5% flow 7.8 FT • Coil leaving water temp 53 °F • Bypass flow 62.5 GPM • Bypass ∆P 7.8 FT • 3-way valve pressure drop 10 FT • Pump flow and head 125 GPM @ 30 FT • Actual return water temp 49 °F (62.5 GPM @ 53 °F+ 62.5 GPM @ 45 °F)
  16. COMMERCIAL BUILDING SERVICES FLOW THINKING Head2 = Head1(Flow2/ Flow1)2 Head2 = 20(.625/1)2 Head2 = 20(.3906 ) Head2 = 7.8
  17. COMMERCIAL BUILDING SERVICES FLOW THINKING ∆T = Load/ Flow X 500 ∆T = 250,000/62.5 X 500 ∆T = 8 Therefore, LWTcoil = 45 + 8 = 53
  18. COMMERCIAL BUILDING SERVICES FLOW THINKING RWT = (Flow1 X EWT + Flow2 X LWT)/ Flow1 + 2 RWT = (62.5 X 45 + 62.5 X 53)/125 RWT = 49
  19. COMMERCIAL BUILDING SERVICES FLOW THINKING 3-way Valve in Mid Position
  20. COMMERCIAL BUILDING SERVICES FLOW THINKING 1.Low return water temperatures. 2.Robs chilled water from other coils at part load conditions. 3.Increases flow in primary piping. 4.Adds additional chillers on line. 5.Chiller performance is reduced. 3-way Valve System Deficiencies
  21. COMMERCIAL BUILDING SERVICES FLOW THINKING 1.1 20 30 40 50 60 70 80 90 100 10 1.0 0.9 0.8 0.7 0.6 0.5 KW per Ton Percent Load Chiller Performance Curve
  22. COMMERCIAL BUILDING SERVICES FLOW THINKING Pump Sizing • Select for full chiller flow • Head must be adequate for: – Chiller evaporator – Longest circuit – Coil – Three way valve – Air separator
  23. COMMERCIAL BUILDING SERVICES FLOW THINKING System Configuration Constant Volume
  24. Any Questions?
  25. Variable Volume Constant Speed
  26. COMMERCIAL BUILDING SERVICES FLOW THINKING Primary – Secondary System Primary – Includes Chillers & Primary Pump. Circuit Constant water flow through the chiller is maintained and chilled water is produced Secondary – Chilled water is circulated to the Circuit demand area (load) by using Secondary pumps. Variable Volume Constant Speed
  27. COMMERCIAL BUILDING SERVICES FLOW THINKING PRIMARY - SECONDARY
  28. COMMERCIAL BUILDING SERVICES FLOW THINKING Other Famous Names of Primary- Secondary Primary – Production Loop Secondary – Distribution Loop
  29. COMMERCIAL BUILDING SERVICES FLOW THINKING Fundamental Idea
  30. COMMERCIAL BUILDING SERVICES FLOW THINKING No Secondary Flow
  31. COMMERCIAL BUILDING SERVICES FLOW THINKING Primary = Secondary
  32. COMMERCIAL BUILDING SERVICES FLOW THINKING Primary > Secondary
  33. COMMERCIAL BUILDING SERVICES FLOW THINKING Primary < Secondary
  34. COMMERCIAL BUILDING SERVICES FLOW THINKING Control Valve in Secondary
  35. COMMERCIAL BUILDING SERVICES FLOW THINKING • Use the flow of the largest chiller – Chiller staging at half of this flow is common • Head loss in common <1 1/2 ft – Distribution pipe size is often used where reductions would be inconvenient • Three pipe diameters between tees – Excessive length increases total head loss • Low velocities in system piping Common Pipe Design Criteria
  36. COMMERCIAL BUILDING SERVICES FLOW THINKING Variable flow through coil Constant flow through system Three Way Valve Variable flow through coil Variable flow through system Two Way Valve Control Valve in Secondary
  37. COMMERCIAL BUILDING SERVICES FLOW THINKING PRIMARY – SECONDARY CIRCUIT Variable Volume Constant Speed
  38. COMMERCIAL BUILDING SERVICES FLOW THINKING Head F1 F2 F3 H1 H2 H3 Flow Control Valves Change the Secondary System Curve
  39. COMMERCIAL BUILDING SERVICES FLOW THINKING % Flow 125 100 75 50 25 150 25 50 75 100 HD Varying differential pressure absorbed by control valve System resistance TDH of pump Pump curve Head Absorbed by 2-way Valves
  40. COMMERCIAL BUILDING SERVICES FLOW THINKING HP 125 100 75 50 25 150 25 50 75 100 % Design Flow Primary Pumps = V/V Secondary Pumps + Constant Flow Primary Pumps, only Pump Horsepower Comparison
  41. COMMERCIAL BUILDING SERVICES FLOW THINKING % Flow 90 80 70 60 50 40 30 20 10 0 10 100 90 80 70 60 50 40 30 20 100 110 120 130 140 150 Base Design HP % % Full Load (Design) HP Pump Over-haded by 150% Constant Flow, C/S Pump (3 Way Valve) Constant Flow, C/S Pump (3 Way Valve) C/S Pump (2 Way Valve) Pump HD Matched to System @ Design Flow C/S Pump (2 W ay Valve) Constant vs Variable Volume
  42. Any Questions?
  43. Step Function of Chillers
  44. COMMERCIAL BUILDING SERVICES FLOW THINKING Production = Distribution
  45. COMMERCIAL BUILDING SERVICES FLOW THINKING Distribution > Production
  46. COMMERCIAL BUILDING SERVICES FLOW THINKING Production > Distribution
  47. COMMERCIAL BUILDING SERVICES FLOW THINKING “Loading” a Chiller • A chiller is a heat transfer device. Like most equipment, it is most efficient at full load. • To “load” a chiller means: – Supply it with its rated flow of water – Insure that water is warm enough to permit removal of rated Btu without freezing the water
  48. COMMERCIAL BUILDING SERVICES FLOW THINKING Chiller Performance Curve 1.1 20 30 40 50 60 70 80 90 100 10 1.0 0.9 0.8 0.7 0.6 0.5 KW per Ton Percent Load
  49. COMMERCIAL BUILDING SERVICES FLOW THINKING Check Valve in Common?
  50. COMMERCIAL BUILDING SERVICES FLOW THINKING What can we do?
  51. COMMERCIAL BUILDING SERVICES FLOW THINKING What else can we do? Reset Supply Temperature • Lower chiller set point when mixing occurs to maintain a constant temperature to the system. • Expect increases in cost of chiller operation at lower set point: 1-3% per degree of reset. • Delays start of the next chiller.
  52. COMMERCIAL BUILDING SERVICES FLOW THINKING What else can we do? • Coils that are selected at higher supply temperatures will not be impaired by small changes. • Loads that require fixed temperatures may use a small chiller to reverse the effects of mixing.
  53. COMMERCIAL BUILDING SERVICES FLOW THINKING Multiple Chillers
  54. COMMERCIAL BUILDING SERVICES FLOW THINKING 60/40 Chiller Split to Help Minimize Low Part Load Operation
  55. COMMERCIAL BUILDING SERVICES FLOW THINKING 0-10 30-40 60-70 90-100 0 5 10 15 20 25 30 0-10 30-40 60-70 90-100 % Time % Load Typical Load Profile
  56. COMMERCIAL BUILDING SERVICES FLOW THINKING Three Unequally Sized Chillers
  57. COMMERCIAL BUILDING SERVICES FLOW THINKING % Load Time Approaching Flow = Load
  58. Any Questions?Alternate Pumping Methods Comparison
  59. COMMERCIAL BUILDING SERVICES FLOW THINKING Two Pipe Direct Return
  60. COMMERCIAL BUILDING SERVICES FLOW THINKING Two Pipe Reverse Return
  61. COMMERCIAL BUILDING SERVICES FLOW THINKING Primary-Secondary Pumping. • Simplest to install. • Simplest to operate. • Flexible in design for present and future. • Efficient to operate. • May over-pressurize near zones.
  62. COMMERCIAL BUILDING SERVICES FLOW THINKING Primary-Secondary-Tertiary
  63. COMMERCIAL BUILDING SERVICES FLOW THINKING Primary-Secondary-Tertiary Pumping. • Best piping flexibility. • Best expansion flexibility. • Provides hydraulic decoupling. • Efficient to operate. • May require added horsepower. • Requires additional pumps and piping. • Increased controls complexity.
  64. COMMERCIAL BUILDING SERVICES FLOW THINKING Primary-Secondary-Tertiary Hybrid
  65. COMMERCIAL BUILDING SERVICES FLOW THINKING Primary-Secondary-Tertiary Hybrid Pumping. • Low present horsepower. • Low future horsepower. • Good piping flexibility. • Good expansion flexibility. • Provides hydraulic decoupling. • May require added horsepower • Requires additional pumps and piping. • Increased controls complexity.
  66. COMMERCIAL BUILDING SERVICES FLOW THINKING Primary-Secondary Zone Pumping
  67. COMMERCIAL BUILDING SERVICES FLOW THINKING Primary-Secondary Zone Pumping. • Low ‘built out’ horsepower. • Low system head. • Increased control complexity. • Present horsepower total higher due to future needs. • Present pumps sized for future requirements. • Difficult to apply in retrofits projects.
  68. Any Questions?
  69. Variable Volume Variable Speed
  70. COMMERCIAL BUILDING SERVICES FLOW THINKING Why Do We Need Variable Speed Secondary Pumps ??? •For Energy Saving…. •For better & optimise operation….
  71. COMMERCIAL BUILDING SERVICES FLOW THINKING How Do We Achieve This Reduction In Power Consumption ?? By Using Variable Frequency Drive and Logic controller with the Secondary Pumps….
  72. COMMERCIAL BUILDING SERVICES FLOW THINKING Power Comparison at Reduced Speed
  73. COMMERCIAL BUILDING SERVICES FLOW THINKING Basic Law which helps in achieving this – Affinity law 1. Flow2 = Flow1(Speed2/ Speed1) 2. Head2 = Head1(Speed2/ Speed1)2 3. BKW2 = BKW1(Speed2/ Speed1)3 If Diameter of Impeller is to be trimmed then instead of speed the same can be used in above formulas.
  74. COMMERCIAL BUILDING SERVICES FLOW THINKING 0 50 100 150 200 250 300 350 400 450 50 100 150 200 250 300 350 400 450 500 Motor Horsepower Annual Operating Cost $1000 $0.10/kWh Operating Cost
  75. COMMERCIAL BUILDING SERVICES FLOW THINKING Head Flow Pump Curve System Curve System Curve as two way valves close Variable flow system
  76. COMMERCIAL BUILDING SERVICES FLOW THINKING Q H Pump Curve System Curve at design flow System Curve at part load Increased head loss Energy savings offset
  77. COMMERCIAL BUILDING SERVICES FLOW THINKING Head Flow Single Pump Pumps in Parallel System Curve Pumps in parallel
  78. COMMERCIAL BUILDING SERVICES FLOW THINKING Horsepower % 100 90 80 70 60 50 40 30 20 10 00 10 20 30 40 50 60 70 80 90 100 Flow % Single Large Pump Two Parallel Pumps Single Parallel Pump Parallel pumping power savings
  79. COMMERCIAL BUILDING SERVICES FLOW THINKING Theoretical Savings
  80. COMMERCIAL BUILDING SERVICES FLOW THINKING 100 % 90 % 80 % 70 % 60 % 50% 40 % 30 % 80 % 85 % 80 % 70 % 60 % 50 % 85 % % Speed Curves Constant Efficiency Curve % Efficiency Head, Feet GPM Establishing Efficiency Curves
  81. COMMERCIAL BUILDING SERVICES FLOW THINKING 750 900 1150 1450 1770 600 900 1150 1450 1770 600 A B C D E 4500 gpm @ 100 FT, 85.9 % Variable Speed Efficiencies
  82. COMMERCIAL BUILDING SERVICES FLOW THINKING “No Valve” System Curve Flow piping head loss curve Distribution Pump TDH Overall system curve Head 80 60 40 20 110 0 200 400 600 800 1000 1200 1400 1600 0 100 Set Point 25 FT Differential Head Maintained Across Load (Set Point)
  83. COMMERCIAL BUILDING SERVICES FLOW THINKING Effect of Constant Set Point piping head loss curve Distribution Pump TDH Overall system curve Head 80 60 40 20 110 0 200 400 600 800 1000 1200 1400 1600 0 Flow 100 Control curve Set point, 25 FT
  84. COMMERCIAL BUILDING SERVICES FLOW THINKING 100% 75% 50% Flow Head Control Curve Variable Head Loss ∆P P1 P2 Control curve
  85. COMMERCIAL BUILDING SERVICES FLOW THINKING Annual Operating Cost ($1000/year @ $0.10/kwh) 50 45 40 35 30 25 20 15 10 05 00 1000 2000 3000 4000 5000 Total Equivalent Pipe Length (feet) Single C/S Pump, No Overheading S i n g l e C / S P u m p , 2 0 0 % O v e r h e a d e d Variable Speed Pump Large systems, long pipe runs
  86. COMMERCIAL BUILDING SERVICES FLOW THINKING Variable Head Loss Ratio Percent Design BHP % Flow 90 80 70 60 50 40 30 20 10 0 10 100 90 80 70 60 50 40 30 20 100 C/S, Constant Flow System Pump Head Matched to System at Design Flow C/S, Variable Flow V/S, 0% Variable Hd Loss, 100% Constant ∆ Hd V/S, 25% Variable Hd Loss, 75% Constant ∆ Hd V/S, 50% Variable Hd Loss, 50% Constant ∆ Hd V/S, 75% Variable Hd Loss, 25% Constant ∆ Hd V/S, 100% Variable Hd Loss, 0% Constant ∆ Hd Base
  87. COMMERCIAL BUILDING SERVICES FLOW THINKING Variable Head Ratio w/ Overheading 90 80 70 60 50 40 30 20 10 0 10 100 90 80 70 60 50 40 30 20 100 110 120 130 140 150 Base Design HP % % Full Load (Design) HP Pump O’Headed by 150% Constant Flow, C/S Pump (3 Way Valve) Constant Flow, C/S Pump (3 Way Valve) C/S Pump (2 Way Valve) Pump HD Matched to System @ Design Flow * 25/75 Means: 25 % Variable HD Loss 75 % Constant HD Loss C/S Pump (2 Way Valve) V/S, 100% Constant HD V/S, 25/75* V/S, 50/50 V/S, 75/25 V/S, 100% Variable HD
  88. COMMERCIAL BUILDING SERVICES FLOW THINKING Locations of Sensor Where to install the Sensor? What type of Sensor?
  89. COMMERCIAL BUILDING SERVICES FLOW THINKING Chillers Primary Pumps Secondary Pumps Load Balancing Valve 2 – Way Valve Panel with PLC & VFD`s Air - Separator Common Single Point Pressure Sensing Single Point Pressure Sensor
  90. COMMERCIAL BUILDING SERVICES FLOW THINKING Single Point Pressure Sensor Is Single Point Pressure Sensor Correct? Wrong !! Why? -Pump is a differential pressure device. -A single point is only influence by pressure. This is good for booster only. -In a closed loop system, system pressure rises due to thermal expansion, pumps will slow down. -When static pressure decrease, pumps will speed up. -This is self-defeating since now the pump speed is not influence by the system load changes, but rather by system water pressure. -Therefore, single pressure sensor are a misapplication in a closed loop HVAC system.
  91. COMMERCIAL BUILDING SERVICES FLOW THINKING Chillers Primary Pumps Secondary Pumps Load Balancing Valve 2 – Way Valve Panel with PLC & VFD`s Air - Separator Common Primary - Secondary Circuit With Variable Speed Secondary Pumps DPT Single Point Differential Pressure Sensor
  92. COMMERCIAL BUILDING SERVICES FLOW THINKING Opening/Closing of 2- Way Valve -Signal from the sensor, installed at load regulates the valve opening & closing. -This way differential across 2-way valve also changes & accordingly output signal is given to PLC. ` ` ` Temperature Sensor Load Output to PFU from DPT 2 Way Valve Control
  93. Question: Can we put the DPT across coil alone?
  94. Question: Across the pumps?
  95. COMMERCIAL BUILDING SERVICES FLOW THINKING Primary - Secondary Circuit With Variable Speed Secondary Pumps Single Point Differential Pressure Sensor To Maximize energy system, we must maximize the variable head loss in the system. This is done by locating the sensor at the most remote zone ( hydraulically) in the system.
  96. COMMERCIAL BUILDING SERVICES FLOW THINKING piping head loss curve Distribution Pump TDH Overall system curve Ft Hd 80 60 40 20 110 0 200 400 600 800 1000 1200 1400 1600 0 Flow, gpm 100 Control curve Set point, 25 FT System Control Curve
  97. COMMERCIAL BUILDING SERVICES FLOW THINKING Variable vs Constant Head Loss
  98. COMMERCIAL BUILDING SERVICES FLOW THINKING The “Active Zone” • Zone set points do not have to be the same. • Pump controller scans all zones often, comparing process variable to set point in each case. • Pumps are controlled to satisfy the worst case. • What happens to the rest of the zones?
  99. COMMERCIAL BUILDING SERVICES FLOW THINKING PFU PMU 4 – 20 mA Set Value From Field Sensor (DPT) PFU – Pump Functional Unit PMU – Pump Management Unit Basic Concept Output To VFD/Pump
  100. COMMERCIAL BUILDING SERVICES FLOW THINKING Chillers Secondary Pumps Balancing Valve DPT DPT Common Panel with PLC & VFD`s Load Different Sensor Signal To Common PFU Panel Multi Point Differential Pressure Sensor
  101. COMMERCIAL BUILDING SERVICES FLOW THINKING PFU PMU Set Value Multiple Process Signals From Field Sensors POSSIBILITY OF MULTIPLE PROCESS SIGNALS FROM DIFFERENT ZONES All zones can have different set values Module VFD VFD Multi Point Differential Pressure Sensor
  102. COMMERCIAL BUILDING SERVICES FLOW THINKING PFU PMU Set Value Multiple Process Signals From Field Sensors POSSIBILITY OF MULTIPLE PROCESS SIGNALS FROM DIFFERENT ZONES All zones can have different set values Signal Comparator VFD VFD Multi Point Differential Pressure Sensor Signal Comparator 4 – 20 mA Sig
  103. COMMERCIAL BUILDING SERVICES FLOW THINKING HVAC Control System DPT Signal Comparator
  104. COMMERCIAL BUILDING SERVICES FLOW THINKING HVAC Control System DPT Signal Comparator - High and Low Signal Selections - Signal Averaging - High/Low Limit Control The module has the addition following features : 1) LED status indications 2) Accepts voltage or milliamp input signal 3) DIP switch-selectable operating modes 4) Accepts 24 VAC/DC power
  105. COMMERCIAL BUILDING SERVICES FLOW THINKING HVAC Control System DPT Signal Comparator Benefits 1) We are able to supply VFD systems with multiple inputs signals ranges to compete with our competitors. 2) We are able to use Grundfos PFU 2000 as the main processor to control the full system operations. 3) We will be minimising outsourcing or external controller in order to serve the HVAC market. 4) The MM allows us to integrate into the system multiple sensor control at a more cost effective price.
  106. COMMERCIAL BUILDING SERVICES FLOW THINKING Other Types of Systems HVAC System
  107. COMMERCIAL BUILDING SERVICES FLOW THINKING Chillers Primary Pumps Balancing Valve Secondary Pumps Air - Separator Expansion Tank Load Panel with PLC & VFD`s Common DPT 2 – Way Valve DPT Separate System for Each Zone
  108. COMMERCIAL BUILDING SERVICES FLOW THINKING Systems In Multi - Zones Two options: 1. Separate Systems can be used for different zones. So each zone will have its own sensor. 2. Signal from different zone sensors is given to the common PFU and most deviated signal, from the set point, is given as output. Separate System for Each Zone
  109. COMMERCIAL BUILDING SERVICES FLOW THINKING Chillers Primary Pumps Balancing Valve Air - Separator Expansion Tank Load Common DPT 2 – Way Valve DPT VFD pumps For Each Zone E-pumps E-pumps Tertiary Pumping System Secondary Pump
  110. COMMERCIAL BUILDING SERVICES FLOW THINKING Reverse Return Pumping Load Air - Separator Chillers Primary Pumps Secondary Pumps Balancing Valve Panel with PLC & VFD`s Common DPT
  111. COMMERCIAL BUILDING SERVICES FLOW THINKING Reverse Return Pumping Benefits : 1) Equalize the pressure drops of each zone. 2) Selections of the sensor becomes easier. 3) If load are similar or symmetrical, 1 centrally located sensor is adequate. 4) As in direct return system, multiple sensor can still provide a benefit to the end user.
  112. COMMERCIAL BUILDING SERVICES FLOW THINKING Type of VFD Systems
  113. COMMERCIAL BUILDING SERVICES FLOW THINKING Possible Options of Variable Speed panels Type ME - Multiple Pumps & Multiple VFDs. Type MF - Common VFD for Multiple Pumps.
  114. COMMERCIAL BUILDING SERVICES FLOW THINKING Signal from Field Sensor(s) (DPT) Panel with PFU & PMU VFD - 1 VFD - 2 Secondary Pumps System with Multi Pumps & Multi VFDs
  115. COMMERCIAL BUILDING SERVICES FLOW THINKING Signal from Field Sensor(s) (DPT) VFD Panel with PFU & PMU Secondary Pumps System with Common VFD for All Pumps
  116. COMMERCIAL BUILDING SERVICES FLOW THINKING APPROVAL FROM INTERNATIONAL AGENCIES Approval from – CE, U/L Conforms to - Electromagnetic compatibility (89/336/EEC) to standard EN 50 081 – 1 and EN 50 082 – 2 and Electrical equipment design 73/23/EEC standard to EN 60 204-1.
  117. COMMERCIAL BUILDING SERVICES FLOW THINKING PFU PMU Single PMU For Control of 8 Zones/Pumps PFU
  118. COMMERCIAL BUILDING SERVICES FLOW THINKING PFU PMU Single PMU For Control of 8 Zones/Pumps PFU PFU PFU
  119. The End
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