Ceiling Radiant Cooling Panels
as a Viable Distributed Parallel
Sensible Cooling Technology
Integrated with Dedicated Outdoor Air Systems
Christopher L. Conroy, E.I.T.
L. D. Astorino Companies, Pittsburgh PA
Stanley A. Mumma, Ph.D., P.E.
Penn State University, Dept. of Architectural Engineering
Presentation Overview
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•
•
Introduction
Radiant Cooling Theory
HVAC Paradigm
Advantages
Example
Integration of Fire Suppression
Conclusions and Solutions
Integrating Dedicated Outdoor Air Systems with
Parallel Terminal Systems
Radiant Cooling Panels
Fan Coil Units
Unitary ACs
Air Handling Units
Unit Ventilators
Radiant Cooling Theory
• Uses both Radiation and
Convection
• Radiation (50-60%)
» Stefan-Boltzmann Equation
» qr = 0.15x10-8 · [(tp+460)4 – (ta+460)4]
• Convection (40-50%)
» ASHRAE S&E 1996
» qc = 0.31 · |tp- ta|0.31 · (tp- ta)
Radiant Cooling Paradigm
• Expensive
» High first cost
» Difficult or improper
installation
» Unavailable
• Condensation!!!
• Condensation!!!
• Condensation!!!
Radiant Cooling Panel Construction
Thermally
Bonded
Blanketed with
Insulation
Aluminum or
Copper Fins
Copper
Tubing
(Serpentine or
Parallel
Arrangement)
Cost Advantages
• Long Term Savings
»
»
»
»
Smaller, More Efficient Chillers
Reduced Fan Energy
Reduced Maintenance Cost
Not paying for Over Ventilating
• Other Cost Savings
» Piping is not insulated
» Reduced Sprinkler Piping
» Testing and Balancing Made Simpler
Indoor Air Quality Advantages
• High comfort levels
• No condensate drains or
drain pans
• Meets ANSI/ASHRAE
Std 62-1999
• Quick response time
• Individual room control at
low cost
Building Advantages
• Architecturally Integratable
» Silk screening available
» Perforated face (acoustics)
• Great for Retrofit or New Construction
» Reduces Mechanical Space
» Less Ductwork
– Less vertical shaft space
– Higher ceilings and/or reduced building heights
• Simpler Coordination Between Trades
» Integration of fire suppression
» Less interferences (crossover ductwork)
Example: Step 1
Defining Parameters
• Open Office Plan
» 1000 ft2
• Define Design Conditions
» 78ºF DBT / 40% RH
» 7 People (20 cfm/person)
• Space Loads
»
»
»
»
7 People (Office Work)
2 W/sq ft (Lighting)
1 W/sq ft (Equipment)
4,000 Btu/h (Skin Loss)
» 14,000 Btu/h (Total Sensible)
» 1,435 Btu/h (Total Latent)
1000 ft2
78°F / 40%
Step 2
Estimation of CRCP Capacity
25.0
20.0
15.0
25.0-30.0
10.0
20.0-25.0
15.0-20.0
5.0
10.0-15.0
(o
F)
DB
T
72
60
58
56
54
76
52
RH (
%)
50
48
46
44
42
0.0
40
Sensible Cooling Capacity (Btuh/ft 2)
30.0
Step 3
Calculation of CRCP Capacity
• Room DPT = 52°F
» 78°F / 40% RH
• DOAS DPT = 44°F
» 1,435 Btuh Latent Load
» 140 cfm @ 55°F
» 3,500 Btuh Sensible Load
• Panel tfi = 55°F
• Panel Temp = 60°F
• Qs = 29.7 Btuh/ft2
» 10,500 Btuh
» 354 ft2 of panel
Step 4
Selection and Layout of CRCP
• 126 4x2 Ceiling Panels
» ~ 1000 ft2
• 24 Light Fixtures
» ~ 20% of Ceiling
• 49 Ceiling Radiant
Cooling Panels
» 392 ft2 (40%)
• 400 sq. ft. Leftover
» Diffusers
» Sprinklers
• Qs = 26.7 Btuh/ft2
» Room RH = 43%
» Increase DOAS DPT
Step 5
Compare Acoustical Performance of CRCP
Reverberation Time (sec)
Acoustical Ceiling Vs CRCP
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
125
250
500
1000
Frequency (Hz)
2000
4000
T
Chilled Water Loop
COMPRESSION
TANK
CRCP’s
ZONE
VALVES
SECONDARY
PUMP
(VFD)
MAKE-UP
PUMP
Integrated Fire Suppression System
ALARM
VALVE
FIRE
FLOW
SWITCH
CHECK
VALVE
FIRE
PUMP
ASSEMBLY
Conclusions and Solutions
• Seen the Advantages
• Concluded that CRCP’s
can be Used Safely with
No Condensation
Problems
• Defined a Simple
Selection Process
• Examined the Opportunity
for Fire Suppression
Integration
• Break the HVAC
Paradigm
» More Successful
Applications
» Spreading the Word
• Explore the Possibilities
of Lowering Cost
» Increase Availability
» Research a way to produce
custom lengths on site
• Development Through the
Solar Industry
Questions