Learning objectives: Discuss the spatial pattern of global interactions
Lecture Objectives: Discuss Project 1 Learn about thermal storage systems.
-
Upload
elfreda-ryan -
Category
Documents
-
view
218 -
download
0
Transcript of Lecture Objectives: Discuss Project 1 Learn about thermal storage systems.
![Page 1: Lecture Objectives: Discuss Project 1 Learn about thermal storage systems.](https://reader030.fdocuments.net/reader030/viewer/2022032415/56649efe5503460f94c12ca5/html5/thumbnails/1.jpg)
Lecture Objectives:
• Discuss Project 1
• Learn about thermal storage systems
![Page 2: Lecture Objectives: Discuss Project 1 Learn about thermal storage systems.](https://reader030.fdocuments.net/reader030/viewer/2022032415/56649efe5503460f94c12ca5/html5/thumbnails/2.jpg)
For Project 1 you will needWet bulb temperature
Empirical equation based on T DB [°C] and RH [0-100]
Exact calculation require solving 3 equations
For this modeling the empirical equation is fine.
![Page 3: Lecture Objectives: Discuss Project 1 Learn about thermal storage systems.](https://reader030.fdocuments.net/reader030/viewer/2022032415/56649efe5503460f94c12ca5/html5/thumbnails/3.jpg)
Merging Two Models
Finally: Find P() or
The only fixed variable is TCWS = 5C (38F) and Pnominal and Qnominal and m cooling tower (Rnominal) for a chiller (defined in nominal operation condition): Based on Q() and WBT you can find P() and COP().
Temperature difference:
R= TCTR -TCTS
22444
2444
2444 ][][ RWBTiWBThgRWBTfWBTedWBTcWBTbaTCTS
Model:
Link between the chiller and tower models is the Q released on the condenser: Q condenser = Qcooling + Pcompressor - First law of Thermodynamics
Q condenser = (mcp)water form tower (TCTR-TCTS) m cooling tower - property of a tower
TCTR= TCTS - Q condenser / (mcp)water
)(
)()(
P
QCOP
![Page 4: Lecture Objectives: Discuss Project 1 Learn about thermal storage systems.](https://reader030.fdocuments.net/reader030/viewer/2022032415/56649efe5503460f94c12ca5/html5/thumbnails/4.jpg)
Example of CHP + Cooling
We need a thermal storage somewhere in this system !
![Page 5: Lecture Objectives: Discuss Project 1 Learn about thermal storage systems.](https://reader030.fdocuments.net/reader030/viewer/2022032415/56649efe5503460f94c12ca5/html5/thumbnails/5.jpg)
Thermal storage
• Store heat• Many issues to consider (∆T, pressure, losses,…. )
• Store cooling energy• Chilled water
• For cooling condenser
• For use in AHU (cooling coils)
• Ice storage • Compact but…
• Other materials (PCMs) that change phase the temperature we need in cooling coils
• Many advantages, but disadvantages too!
![Page 6: Lecture Objectives: Discuss Project 1 Learn about thermal storage systems.](https://reader030.fdocuments.net/reader030/viewer/2022032415/56649efe5503460f94c12ca5/html5/thumbnails/6.jpg)
On-Peak and Off-Peak Periods
This profile depends on the type of building(s) !
![Page 7: Lecture Objectives: Discuss Project 1 Learn about thermal storage systems.](https://reader030.fdocuments.net/reader030/viewer/2022032415/56649efe5503460f94c12ca5/html5/thumbnails/7.jpg)
Chilled water tank
Use of stored cooling energy
Store Use
![Page 8: Lecture Objectives: Discuss Project 1 Learn about thermal storage systems.](https://reader030.fdocuments.net/reader030/viewer/2022032415/56649efe5503460f94c12ca5/html5/thumbnails/8.jpg)
Which one is better ?
Depends on what you want to achieve:-Peak electric power reduction-Capacity reduction-…..
![Page 9: Lecture Objectives: Discuss Project 1 Learn about thermal storage systems.](https://reader030.fdocuments.net/reader030/viewer/2022032415/56649efe5503460f94c12ca5/html5/thumbnails/9.jpg)
Downsizing the Chiller
• Lower utility costsLower on-peak electrical consumption(kWh)Lower on-peak electrical demand (kW)
• Smaller equipment sizeSmaller chillerSmaller electrical service (A)
• Reduced installed costMay qualify for utility rebates or other incentives
![Page 10: Lecture Objectives: Discuss Project 1 Learn about thermal storage systems.](https://reader030.fdocuments.net/reader030/viewer/2022032415/56649efe5503460f94c12ca5/html5/thumbnails/10.jpg)
Sizing storage system (use Annual Cooling-Load Profile)
How often you need to use it?What are the cost-benefit curves ? What is the optimum size ?
![Page 11: Lecture Objectives: Discuss Project 1 Learn about thermal storage systems.](https://reader030.fdocuments.net/reader030/viewer/2022032415/56649efe5503460f94c12ca5/html5/thumbnails/11.jpg)
Stratified chilled water tanks
![Page 12: Lecture Objectives: Discuss Project 1 Learn about thermal storage systems.](https://reader030.fdocuments.net/reader030/viewer/2022032415/56649efe5503460f94c12ca5/html5/thumbnails/12.jpg)
Temperature and dynamics Temperature at outlet during the changing cycle of the tanks
![Page 13: Lecture Objectives: Discuss Project 1 Learn about thermal storage systems.](https://reader030.fdocuments.net/reader030/viewer/2022032415/56649efe5503460f94c12ca5/html5/thumbnails/13.jpg)
Stratified chilled water tanksdiffuser geometry
Challenge:“Pull” large amount of energy withoutdisturbing stratification
![Page 14: Lecture Objectives: Discuss Project 1 Learn about thermal storage systems.](https://reader030.fdocuments.net/reader030/viewer/2022032415/56649efe5503460f94c12ca5/html5/thumbnails/14.jpg)
Ice Storage Tank
Many issues !….As freezing progresses progress the ice becomes thicker and significantly impedes heat transfer
![Page 15: Lecture Objectives: Discuss Project 1 Learn about thermal storage systems.](https://reader030.fdocuments.net/reader030/viewer/2022032415/56649efe5503460f94c12ca5/html5/thumbnails/15.jpg)
Open Ice Storage Tank
Also issues !…..
![Page 16: Lecture Objectives: Discuss Project 1 Learn about thermal storage systems.](https://reader030.fdocuments.net/reader030/viewer/2022032415/56649efe5503460f94c12ca5/html5/thumbnails/16.jpg)
Fluid Flow Rate and Freeze ΔT
![Page 17: Lecture Objectives: Discuss Project 1 Learn about thermal storage systems.](https://reader030.fdocuments.net/reader030/viewer/2022032415/56649efe5503460f94c12ca5/html5/thumbnails/17.jpg)
Impact on Chiller Efficiency
![Page 18: Lecture Objectives: Discuss Project 1 Learn about thermal storage systems.](https://reader030.fdocuments.net/reader030/viewer/2022032415/56649efe5503460f94c12ca5/html5/thumbnails/18.jpg)
PCMs
A. Sharma et al. / Renewable and Sustainable Energy Reviews 13 (2009) http://www.docunator.com/bigdata/1/1367142535_c566e7d75e/reviewexample2.pdf
![Page 19: Lecture Objectives: Discuss Project 1 Learn about thermal storage systems.](https://reader030.fdocuments.net/reader030/viewer/2022032415/56649efe5503460f94c12ca5/html5/thumbnails/19.jpg)
Other latent heat thermal storage systems (research is ongoing)
![Page 20: Lecture Objectives: Discuss Project 1 Learn about thermal storage systems.](https://reader030.fdocuments.net/reader030/viewer/2022032415/56649efe5503460f94c12ca5/html5/thumbnails/20.jpg)
Construction and benefits Active
Passive (wall)
![Page 21: Lecture Objectives: Discuss Project 1 Learn about thermal storage systems.](https://reader030.fdocuments.net/reader030/viewer/2022032415/56649efe5503460f94c12ca5/html5/thumbnails/21.jpg)
Modeling(stratified tank)
Write energy and mass balancer equation for each section
![Page 22: Lecture Objectives: Discuss Project 1 Learn about thermal storage systems.](https://reader030.fdocuments.net/reader030/viewer/2022032415/56649efe5503460f94c12ca5/html5/thumbnails/22.jpg)
Installation of thermal storage system
DownstreamUpstream
• Increases chiller efficiency • Increases chiller capacity • Overall system efficiency ??? • Decreases storage capacity• Simplifies system layout• …..
• Decreases chiller efficiency• Decreases chiller capacityOverall system efficiency ???• Increases storage capacity•……• Does not allow chiller shut down!