Project

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Project
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Project

• FINAL PROJECT DELIVERABLES
•  
• 1) PROJECT REPORT
• - Project statement (introduction) 2 pages
• Explain what are you designing/analyzing and why
  is that important
• On the second page
  clearly identify (bullet list) project outcomes
• - Building description (geometry) 1-3 pages
• Schematics that focus on your system(s)
• Identify all assumptions and simplifications
  you introduced
• - Methodology 1-3 pages
• Describe methodology (equations, schematics, )
• Provide a list of assumptions used in your
  methodology
• - Results 3-5 pages
• Formatted results with comments
• Tables, Charts, Diagrams,
• Analysis and Results discussion
• - Summary 0.5-1 page
• Summary of most important results

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Project

• Grading criteria
•  
• 1) Approach and solution quality 60
• - Methodology 20
• - Accuracy 20
• Result analysis 20
• 2) Deliverables 40
• - Final report 40
• - clarity
• - completeness
• - steed assumptions and limitations
• - quality of graphs, tables schematics,.

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Objectives

• Learn about
• 1) DOAS
• - Principle of operation
• - Design
• - Advantages and disadvantages
• 2) Control for HVAC systems
• - Economizers (Psychrometrics) and control
• - Heat recovery systems (Psychrometrics)

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www.doas.psu.eduDOAS with multi-split systems

• Fresh air?

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DOAS fresh air configurations
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DOAS fresh air configurations
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Issues Related to DOAS

• Split of sensible and latent load
• Selection of hydronic system
• Winter vs. summer operation
• Winter operation with DX systems (heat pump)

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Economizer

• Economizer (fresh air volume flow rate control)

• Controlled device is damper
• - Damper for the air
• - Valve for the CC

fresh air
damper
mixing
recirc. air
T RH sensors
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Economizer cooling regime

• How to control the fresh air volume flow rate?

• If TOA lt Tset-point ? Supply more fresh air
  than the minimum required
• The question is how much?
• Open the damper for the fresh air
• and compare the Troom with the Tset-point .
• Open till you get the Troom Tset-point
• If you have 100 fresh air and your
• still need cooling use cooling coil.
• What are the priorities
• - Control the dampers and then the cooling coils
  or
• - Control the valves of cooling coil and then
  the dampers ?
• Defend by SEQUENCE OF OERATION
• the set of operation which HVAC designer provides
  to the automatic control engineer

fresh air
100
Minimum for ventilation
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Economizer cooling regime

• Example of SEQUENCE OF OERATIONS
• If TOA lt Tset-point open the fresh air damper
  the maximum position
• Then, if Tindoor air lt Tset-point start
  closing the cooling coil valve
• If cooling coil valve is closed and T indoor air
  lt Tset-point start closing the damper
• till you get T indoor air T set-point
• Other variations are possible

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Sequence of operation for the humidity control
system design
Adiabatic humidifier
CC
HC
SA
OA

• mixing

RA

• Define the sequence of operation for
• WINTER operation and
• - case when humidity is not controlled
• - case when humidity is precisely controlled

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Sensible and Enthalpy and Desiccant wheels
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Sensible and Enthalpy Wheels
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Desiccant wheel