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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