Web Based BACnet Compatible Controls Applied to Emerging HVAC Technologies

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Web Based BACnet Compatible Controls Applied to
Emerging HVAC Technologies
ASHRAE Orlando Seminar 8, February 6, 2005

• Stanley A. Mumma, Ph.D., P.E.Prof. Architectural
  EngineeringPenn State University _at_ Univ.
  Parksam11_at_psu.eduhttp//doas-radiant.psu.edu

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Presentation Outline

• Emerging Technologies EW, DOAS, CRCP, Continual
  Performance monitoring
• Practical Application
• EW Control 3 regions, w/ frost control
• CRCP condensate control
• Control Logic, (Symp. paper OR-05-3-3)
• Some benefits of employing Web Based Ctrl
• Some benefits of using BACnet
• Conclusions and recommendations

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DOE Report
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2
1
3
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The Technologies Integrated
High Induction Diffuser
20-70 less OA,
Cool/Dry Supply
DOAS Unit W/ Energy Recovery
Building With Sensible and Latent cooling
decoupled
Parallel Sen. Radiant Cooling System
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Practical Application
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Practical Application Contd
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Practical Application Graphic
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EW Control
Region 1
Region 2
Region 3
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CRCP Condensate Control

• First Stage keep panel inlet fluid temperature
  above the space DPT.
• Second Stage Use a passive fail safe condensate
  sensor, with a spring return temperature control
  valve to isolate CRCP from source of cooling, if
  condensate sensed.
• Alt Second Stage, for buildings with movable
  sash Monitor the sash position and act as
  appropriate.

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Sash Position Condensation Control
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The System Control LogicSingle Zone, or
Multi-Zone
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Now the Web BasedControl Discussion
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Web Based

• Facilitates system monitoring and control from
  anywhere. We could do it here if we had an
  internet connection.
• Access to system and trend logs lead to
  discoveries and refinements, previously hard to
  realize. (an example will follow)
• Can facilitate occupant participation (an example
  will follow).

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An Example RefinementWinter Supply Air
Temperature
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Observations

• EW is operating in the on-off mode
• Supply air temperature to the space varies from
  about 35F to 65F. Good that high induction
  diffusers are used.
• It only takes about 20 minutes for the space
  temperature to drop 1F (control set to hold space
  temperature between 73 and 74F)
• In some cases the SAT remains at OA temperature
  for over 3 hours.

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What are the Alternatives?

• Modulate the EW speed to prevent on-off cycling.

Capacity control in first 5 rpm
e
5
0
20 rpm
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Operating the panel pumpin the winter with EW
On-off
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EW on-off w/ w/o panel pump
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Panel Inlet Water Temperature As The EW Cycles
On-off.
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An Example of Occupant Participation aided by web
access
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Now the BACnet Compatible Control Discussion
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BACnet Advantages, even in this very small
project.

• Enables web access from anyplace with an internet
  connection.
• Performance and control available from the campus
  central computer system.
• Enables expansion of a full control module to
  accommodate more inputs/outputs .
• Impacts the ease and cost of installation.
• May reduce mislabeled points.

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Web Browser
Server
Digital, I
Cond Window t5t14 t1, h1t4,
h4 CO2-1CO2-2 FM1FM5
SF RF EW Ch1 Ch2 Panel P D1 V1V2V3
Router
Digital, O
Control Module
Analog, I
Analog, O
Analog, I
24VPower Supply
Chiller
FAV
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What If the FAV Had a BACnet Control?

• Could connect the FAV control to the BACnet MS/TP
  network.
• Free 5 input connections and associated wire and
  installation
• Free 4 output connections and associated wire and
  installation.
• 15 of the input and 40 of the output
  connections now eliminated.

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Web Browser
Server
Digital, I
Cond Window t5t14 t1, h1t4,
h4 CO2-1CO2-2 FM1FM5
SF RF EW Ch1 Ch2 Panel P D1 V1V2V3
FAV
Router
Digital, O
Control Module
Analog, I
Analog, O
Analog, I
24VPower Supply
Chiller
FAV
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What If the Chiller Had a BACnet Control?

• Could connect the Chiller control to the BACnet
  MS/TP network.
• Free 3 input connections and associated wire and
  installation
• Free 3 output connections and associated wire and
  installation.
• Another 12 of the input and 30 of the output
  connections eliminated

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Web Browser
Server
Digital, I
Cond Window t5t14 t1, h1t4,
h4 CO2-1CO2-2 FM1FM5
SF RF EW Ch1 Ch2 Panel P D1 V1V2V3
FAV
Ch
Router
Digital, O
Control Module
Analog, I
Analog, O
Analog, I
24VPower Supply
Chiller
FAV
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What If the Air Flow Measuring Devices were
BACnet Enabled?

• Could connect the 3 Air Flow Measuring Stations
  to the BACnet MS/TP network.
• Free 5 input connections and associated wire and
  installation.
• Another 19 of the input connections now
  eliminated.
• If all 3 changes were implemented, 46 of the
  input and 70 of the output connections
  eliminated. And associated wire and installation.

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Web Browser
Server
Digital, I
Air FM
Cond Window t5t14 t1, h1t4,
h4 CO2-1CO2-2 FM1FM5
SF RF EW Ch1 Ch2 Panel P D1 V1V2V3
FAV
Ch
Router
Digital, O
Control Module
Analog, I
Analog, O
Analog, I
24VPower Supply
Chiller
FAV
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Impact On Wire Pulling, Terminating Expansion
Modules!
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Conclusions

• Control of this system employing EW, CRCP, DOAS,
  and Chiller was successfully achieved.
• Web accessibility made a complete under-standing
  of the system performance possible.
• Web accessibility made control logic revisions
  easy.
• BACnet capability has the potential to reduce the
  installation costs if properly considered at the
  beginning, or
• Free up input and output terminals on existing
  control modules, allowing expansion.

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QUESTIONS