1. Piping Systems

2. Piping Systems SERIES LOOP MONOFLO SYSTEM DIRECT RETURN REVERSE RETURN
PRIMARY/SECONDARY SYSTEM
BASIC PRIMARY SYSTEM
SYSTEM SYZER

4. Hydronic System Open System Static Head Loss Friction Loss
Valve and Fitting Loss
Atmospheric Pressure
NPSH(a) vs. NPSH(r)

5. Hydronic System Open System Static Head Loss Friction Loss
Cooling
Tower
Static Head Loss
Friction Loss
Valve and Fitting Loss
Atmospheric Pressure
NPSH(a) vs. NPSH(r)
Chiller

6. Open System Pressures Pump Pipe Friction Loss (Varies with flow) Total
Static
Head
Condenser
Total
Suction
Head
(Known head loss)
Basin Water
Level
Pump

7. Backflow Preventer Storage Water Heater DHW System HW CW HW CW HW CW
Cooling Tower
DHW System HW CW HW CW HW CW
City
Main
Water
Heater
Water
Heater
Water
Meter
Backflow
Preventer
PRV
Pump

8. Hydronic System Closed System Friction loss Valve and Fitting Loss
NO Static Head Loss
Pressurized System

9. Closed System Pressures
Multi-Level Building
1 PSI = 2.31 Feet
Head (ft) = head (psi) x 2.31
specific gravity

10. Closed System Pressures
Example: 4-Story Building
60 feet to top of system
26 PSI of Static Pressure
Static Pressure (26 PSI)
+Minimum Pressure (4 PSI)
30 PSI
PRV setting = 30 PSI

11. Closed System Pressures
Example: Single Story Building
12 PSI fill pressure
System can be 18 feet tall

12. Series Loop Piping

13. Monoflo System

14. Direct Return
Pressure Calculations – Low Head Pressures (Piping in parallel)
Heat Loss – Constant supply temperatures per load

15. Direct Return Piping

16. Reverse Return

17. Reverse Return Piping

18. Primary-Secondary Direct Return
Supply
Secondary Pumps
Primary - secondary
Common
Return
Primary Pumps 18 18

19. Primary-Secondary Reverse Return
Terminals
Terminals
Terminals
Supply
Supply
Return
Secondary
Pump
Return
Primary
Chiller
Pumps
Common
Pipe 19 19

20. Primary-Secondary-Tertiary
Zone C
Zone A
Zone B
Tertiary Pumps
Common
Pipe
Secondary Pumps
Modulating
Control Valves
Optional Variable
Speed Pump
DP Sensor
Common Pipe 20
Primary Pumps 20

21. Primary-Secondary-Tertiary Hybrid
Zone C
Zone A
Zone B
Tertiary Pump
Supply
Secondary Pumps
Common Pipe
Primary
Pumps
Return

22. Primary Variable Speed
Two-position Control Valves
Flow Meter
DP Sensor
Modulating
Valve
The newest tool available to the designer is primary variable speed.
Floor space can be gained in the equipment room as well a increased operating efficiencies, especially in single chiller designs.
Control of this type of system is much more complex and doses not lend well to many retrofit opportunities.
VFD
VFD
VFD 22 22

23. Primary / Secondary
Terminology: “Pump #1 can be referred to as the source or primary pump and pump #2 as the load or secondary pump.” – 2004 ASHRAE Systems and Equipment Handbook, page 12.7

24. The flow rate entering a tee must equal the flow rate leaving the tee!
Law of the “T”
The flow rate entering a tee must equal the flow rate leaving the tee!

25. Law of the “T”
50 GPM
100 GPM
50 GPM

26. Law of the “T”
50 GPM
100 GPM
150 GPM

27. Law of the “T”
50 GPM
50 GPM
100 GPM
100 GPM
50 GPM

28. Law of the “T”
100 GPM
100 GPM
100 GPM
100 GPM
0 GPM

29. Law of the “T”
175 GPM
175 GPM
100 GPM
100 GPM
75 GPM

30. Prim. / Sec. -- Basics -- Common Pipe
PRIMARY
SECONDARY

31. Prim. / Sec. -- Basics -- Common Pipe Flow
Pump OFF A B
100 gpm

32. Prim. / Sec. -- Basics -- Common Pipe Flow
Pump ON gpm
100 gpm gpm A B

33. Prim. / Sec. -- Basics -- Common Pipe Flow
Pump ON - 50 gpm A
100 gpm gpm B
tee

34. Prim. / Sec. -- Basics -- Common Pipe Flow
Pump ON gpm A B
100 gpm gpm
tee

35. Primary / Secondary --Bridge
SUPPLY
RETURN
PRIMARY / SECONDARY
COMMON

36. P/S bridge - Front Loaded Common
Load = Production
(flow in gpm)
HWS TEMP F
500
SECONDARY
PUMPS
500
OFF ON
COMMON -- NO FLOW
500
500
EHW TEMP.
150 F
HWR TEMP F

37. P/S bridge - Front Loaded Common
Load > Production
(flow in gpm)
HWS TEMP F
500
SECONDARY
PUMPS
700
OFF ON
MIXING 180) + 150)
500
COMMON
700
EHW TEMP.
150 F
HWR TEMP F

38. Bridge Check Valve
SUPPLY
RETURN
COMMON

39. P/S bridge - Front Loaded Common
Production > Load
(flow in gpm)
HWS TEMP. 180F
1000
SECONDARY
PUMPS
800 ON ON
COMMON
500
500
MIXING + 180)
800
Equally Loaded
EHW TEMP.
156 F
HWR TEMP F

40. Primary-Secondary System Relationship
SUPPLY
RETURN
PRIMARY / SECONDARY
COMMON
Step Function
Linear Function

41. Single Boiler - Primary / Secondary
HWS T3 T1
Boiler
3-10 pipe diameters between Tees T2 T4
HWR
Single Boiler - Primary / Secondary

42. Dual Boiler - Primary / Secondary
Boiler Control
Boiler
HWS
HWR T1 T5 T6 T2 T3 T4 T7
Dual Boiler - Primary / Secondary

43. Dual Boiler - Primary / Secondary
HWS T5 T3 T1
Boiler
Boiler T7 T4 T2 T6
HWR
Dual Boiler - Primary / Secondary

44. Four Boiler Primary Secondary System. .

45. Low Temperature Application Water Source Heat Pump or Radiant Heating
Problems:
Boiler Condensation!
Fire tube: 160
Water tube: 140
Copper fin tube: 105
Version #1
B&G balance valves w/
bypass line to
provide high temp inlet
water to boiler
HWS T3 T1
Boiler
3-10 pipe diameters between Tees T2 T4
HWR
Single Boiler - Primary / Secondary

46. Low Temperature Application Water Source Heat Pump or Radiant Heating
Problems:
Boiler Condensation!
Fire tube: 160
Water tube: 140
Copper fin tube: 105
Version #2
FPE Valve w/
bypass line to
provide high temp inlet
water to boiler
HWS T3 T1
Boiler
3-10 pipe diameters between Tees T2 T4
HWR
Single Boiler - Primary / Secondary

47. Low Temperature Applications
Alternate: Condensing Boiler

48. Primary Only Piping
For boilers that can handle variable flow

49. System Syzer Calculator
Circular Slide Rule
Analog Calculator
Extremely Helpful Tool

50. Explanation
Non-product specific
Water Use Only

51. Heat Transfer Formula Q = m CP (T2 - T1) Btu / Hr =
Energy = mass flow x specific heat x Delta T lb
1 Btu °F
Btu / Hr = Hr
8.34 lb
1 Btu °F lb
60 Min
1 Hour
Min
1 Gallon
X Gal
Btu / Hr =
Energy = mass flow x specific heat x Delta T
Btu / Hr = 500 GPM T

52. Scale 1: Heat Transfer / Flow
1 MBH = 1000 Btu/hr
Δt from 1 to 200º F

53. Scale 1 - Example Problem
Determine flow required for 150,000 Bth/hr using a 300DT.
10 gpm

54. “Tons” of refrigeration

55. Scale 1 - Example Problem
Determine flow required for 20 tons cooling using a 100Dt. 20 tons x 12,000 BTUH/ton = 240,000 BTUH or 240 MBH
48 gpm

56. Scale 2: Pipe Sizing
Window
Milinch
Ft/100ft
ASHRAE

57. Scale 2: Example Problem
Determine pipe size for 70 gpm in a typical hydronic system.
2½” Pipe
3.5’/100’
3” Pipe
1.2’/100’

58. Scale 3: Flow Velocity
Works with Scale 2

59. Scale 3: Example Problem
What is the velocity of 1600 gpm through an 8” pipe? Problems?
10+ fps

60. Scale 3: Example Problem
What is the velocity of 1600 gpm through an 8” pipe? Problems?
7 fps

61. Pipe Sizing / Fitting Pressure Drop
System Syzer Jacket
Based On Hydraulic Institute Standards
One Method, There Are Others!

62. Equivalent Lengths Table
11’

63. Scale 4: Description Pipe Length - TEL - 50% rule Friction Loss
Total Pressure Drop

64. Scale 4: Example Problem
What is the total pressure drop in a pipe with a TEL of 130’ and flow rate of 200 gpm?
Scale 2
2.3’/100’
Or….
2.3’/100’ x 130’ = 3’

65. Scale 4: Example Problem
The TEL of the longest circuit is 1500’. The head loss rate in the system piping is 3.4’/100’ at design flow. How much head does the pump have to provide to overcome the piping head loss?
1500’
3.4’/100’
50’

66. Scale 5: Flow/Head Relationship
Q1= Known (design) flow
Q2 = Final flow
h1 = Known (design) head
h2 = Final head

67. Scale 5: Example Problem
A chiller has 12’ head loss at 100 gpm. What is its head loss at 150 gpm?
27’

68. Scale 5: Example Problem
A closed system has a flow rate of 200 gpm and a head loss of 30’. Plot the system curve.
Flow vs
Head

69. Plotting the System Curve