objectives - finish with pumps and plumbing example - learn about district cooling and heating...

Objectives

- Finish with pumps and plumbing example

- Learn about district cooling and heating systems

System Curves

A B∆p

V

A+B

ParallelA B

A B

∆p

V

A+B

A

B

Serial

System balancing

BOILER

HC2

AHU1 AHU2

HC1

pump

100 ft 1000 ft

2 gpm 10 gpm

10 ft

Pumps• Raise pressure and produce flow

• Main type• Centrifugal

Inline Base mounted

Example of Turbine pump

Reading (textbook)Page 3-36 - 3-45

http://www.taylor-engineering.com/downloads/cooltools/EDR_DesignGuidelines_CoolToolsChilledWater.pdf

Curve for Multiple Pumps

Changing Pump Speed

HW5: Find a system curve for this plumbing configuration

Primary/Secondary and Tertiary Pumping

Taylor, S., P. Dupont, B. Jones, T. Hartman and M. Hydeman. 2000. Chilled water plant design guide. San Francisco: Pacific Gas & Electric Company.

http://www.taylor-engineering.com/downloads/cooltools/EDR_DesignGuidelines_CoolToolsChilledWater.pdf

Reading Assignment:

Hydronic systems for district cooling/heating and buildings

Constant-Flow System, Single Chiller, Single Coil Constant-Flow System, Single Chiller, Multiple Coils

Mixing valve that control by-pass flow Major pumping force is the chiller pump

Control of coil temperature Mixing valve that control the flow through the coil Flow Variation as a Function of Valve Position

Major pumping force is the chiller pump

Same pressure drop like a cooling coil

Multiple chiller (or boilers) Parallel Serial

Primary-Loop Only VariableSpeed Flow

Single chiller Multiple chillers

Primary and Secondary Loop Variable Flow Design

Parallel chillers

Serial chillers

Large Plant or Building Distribution Systems

Primary/Secondary Loops with Variable Flow and Distributed Pumping

Primary/Secondary and Tertiary Pumping

Primary Pump ArrangementsDedicate a pump for each chiller

Provide a common header for the pumps

Coil Pumping Strategies

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

Impact of plumbing on acooling coil

Plumbing Arrangement in Building’s hydronic systems

Fan coil systems Baseboard heaters

Radiators

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=0CCUQFjAA&url=http%3A%2F%2Fbookstore.ashrae.biz%2Fjournal%2Fdownload.php%3Ffile%3Dhegberg.pdf&ei=IvcqU_O1KMuE2AWgloHgDA&usg=AFQjCNFRAMzPnbzDpAluhyk4l8u_SKKTdw

Control Valve Selection For Hydronic Systems

Before DC we tried to do this

Valve authority