Objectives

- Introduce HW5 – Plumbing

- Learn about district cooling and heating systems

HW5: Find a system curve for this plumbing configuration

200 ft

200 ft

30 ft30 ft

20 ft20 ft40 ft

40 ft

30 ft

30 ft

10 ft 10 ft

10 ft

10 ft20 ft

5 ft

5 ft

5 ft5 ft

5 ft

5 ft

10 ton

10 ton

Final project – Modeling HW5 – Design

Due date: April 30th

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 Digital Control we tried to do this

Valve authority

Boilers

Coal Boiler

Coal burning method

Long time ago:

Today:

1) Fluidized bed: http://www.youtube.com/watch?v=8n78CDI3GoU

2) Powdered coal:http://www.youtube.com/watch?v=g1ojza-nbqs

Coal-fired power plant filters

• For Particulate Maters• Electrostatic precipitator

• Filter bags

• Scrubber for SO2 (to prevent formation of Sulfuric acid – H2SO4)• Grinded Limestone in water (slurry) sprayed into the gas fluid

stream SO2 + Limestone slurry → Gypsum (used for wallboard)

Oil – Gas based boilers

Gas circulate through tubes water is in-between

Water tube boiler

Furnaces

For homes

Roof tops and induct heaters