Lecture Objectives Plumbing Hydronic distribution systems ChillerBoiler Storage

Lecture Objectives: • Plumbing • Hydronic distribution systems – Chiller/Boiler – Storage – Building • Pumps Reading assignment: Chilled Water Plant Design Guide (Section 4) http: //energydesignresources. com/media/2305/EDR_Design. Guidelines_Cool. Tools. Chilled. Water. pdf

Primary/Secondary and Tertiary Pumping (schematics A&B below)

Coil Pumping Strategies Variable speed pumps vs. Single pas Valve vs. Mixing valves vs. Diverting Valves

Impact of Piping Coil How will this affect needed CHW flow? What about the chiller performance?

Plumbing Arrangement in Building’s Hydronic Systems Radiators Baseboard heaters Fan coil systems

What is the difference between these two configuration?

Hydronic Terms • Head loss • Open-loop vs. closed loop • Open System h Pump • Closed System Chiller Pump Cooling coil in AHU

Is this open or closed system ? Cooling towers

Relationship between velocity in a pipe and pressure drop Δp ~ v 2 Δp = Constant × v 2 Required power (P) for the pump P = V × Δp Δp [Pa or ft water] smaller pipe larger pipe P –power [W], V –volume flow rate [m 3/s], Δp – pressure drop [Pa] v – velocity [m/s] Δp ~ v 2 (Δp ~ V 2 – when same pipe is used) P ~ V × V 2 – when same pipe is used P ~ V 3 P 2/P 1 = (V 2/V 1)3 For the same pipe When different pipe is used for the same flow rate: For the same flow rate V Reduction of D: D 1 A 1 V 1 P 1 D 2= D 1/2 A 2=1/22 A 1 V 2=22 V 1 P 2/P 1 = (D 1/D 2)4 - for the same flow rate or 50% smaller diameter of the pipe v [m/s or fpm] for the same flow rate wee have: 4 times larger velocity 16 times larger pressure drop and 16 times lager power for the pump

Head Loss

Fittings

Pumps • Raise pressure and produce flow • Main type • Centrifugal Example of Turbine pump Inline Reading (textbook) Page 3 -36 - 3 -45 Base mounted

Pump curves • NPSHR = Net Positive Suction Head Required

Changing Pump Speed

Net Positive Suction Head (cavitation)

Curve for Multiple Pumps

System Curves ∆p A+B B A+B A B V A B Parallel V A B Serial

Find a system curve for this plumbing configuration

System balancing AHU 1 AHU 2 HC 1 HC 2 100 ft 10 gpm 2 gpm 10 ft pump BOILER

Valves • Section 5 -14 and 6 -15 in the textbook • Types • Butterfly Valves • Ball Valves • Globe Valves Three way valves

Valve Sizing and Flow Coefficient Cv value: in liter/hour or…. in Pa Control Valve Selection For Hydronic Systems reference: http: //www. google. com/url? sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact =8&ved=0 CCUQFj. AA&url=http%3 A%2 F%2 Fbookstore. ashrae. biz%2 Fjournal%2 Fdo wnload. php%3 Ffile%3 Dhegberg. pdf&ei=Ivcq. U_O 1 KMu. E 2 AWglo. Hg. DA&usg=AFQj. CN FRAMz. Pnbz. Dp. Aluhyk 4 l 8 u_SKKTdw

Control Valve Selection For Hydronic Systems Before DC we tried to do this Valve authority