Title: Energy Conservation Benefits of a DOAS with Parallel Sensible Cooling by Ceiling Radiant Panels
1Energy Conservation Benefits of a DOAS with
Parallel Sensible Cooling by Ceiling Radiant
Panels
- Jae-Weon Jeong
- Stanley A. Mumma, Ph.D., P.E.
- William P. Bahnfleth, Ph.D., P.E.
- Department of Architectural Engineering
- The Pennsylvania State University
- (e-mail jqj102_at_psu.edu)
2Presentation Outline
- Research background
- Pilot DOAS/CRCP system
- Energy simulation overview
- Energy conservation effects of the DOAS/CRCP
system
3Problems of All-Air VAV
- Multiple spaces equation (ASHRAE Std. 62)
- Does not guarantee that individual space will
always receive the intended OA quantity - Conditioning and transporting air
- Consumes large quantities of energy
- Part load humidity problem
- Space humidity is passively controlled
4DOAS with Parallel Cooling
5Pilot DOAS/CRCP system
- Space Conditions
- 3200 ft2 studio (43 X 74)
- 14 ceiling height with 8 rows of pendent
illumination at the 9-ft plane - 40 students
- Office equipments (desk lamps, personal computers)
6Pilot System Configuration
Two 5-ton Air Cooled Chillers
3-Way Valve (Panel CHW Supply Temp Control)
3-Way Valve (SA Temp Control)
High Induction Diffuser
Enthalpy Wheel
8 rows, 2 X 13 CRCPs
Variable Speed Drive (modulated EW speed)
Cooling Coil
7System Operating Stages
Panel Pump is activated
Maintain Space DPT DBT set-point
Tp Space DPT 3F
If Space DBT gt 75F (set-point) when SA 52F
(lower limit)
8EW and C/C controls
EW Full Speed C/C Modulate
(maintain SA condition)
hEA
A
EA
EW Off C/C Modulate (maintain SA
condition)
B
C
EW Speed Modulation (maintain SA
DPT) C/C Modulate or Off (maintain SA
condition)
SA DPT ( 52F)
9Energy Simulation
- Simulated the pilot system and a VAV serving the
same space - For DOAS/CRCP pilot system simulation
- General purpose equation solving software
- General reciprocating air-cooled chiller model
- Quasi-steady CRCP model
- Curve-fit of Manufacturers EW performance data
- General Fan and Pump models were used
10Energy Simulation
- For conventional VAV system simulation
- Commercial energy analysis program was used
- For common base simulation
- Identical chiller part-load characteristic
- Identical hourly space sensible latent loads
- Identical weather data (Williamsport, PA) were
used
11Cooling Coil Load
VAV
57 of Peak C/C Load is shiftedto the EW
7.6 of Annual C/C Load was reduced
DOAS/CRCP
VAV
DOAS/CRCP
Operated for more hours
12Chiller Energy Reduction
29 reduction
- Chiller Size
- VAV system 14 ton
- DOAS/CRCP pilot system 10 ton
- Annual Chiller Energy Consumption
- VAV system 10.6 MWh/y (3.7 seasonal COP)
- DOAS/CRCP pilot system 7.9 MWh/y (4.5 seasonal
COP)
25 reduction
13Fan and Pumping Energy
37 of VAV
- Fan Energy Reduction
- Design SA quantity DOAS 1200 scfm
VAV 3220 scfm - Annual Fan energy DOAS 2.33 MWh/y
VAV 7.97 MWh/y - Pumping Energy
- DOAS/CRCP system consumes as
much pumping energy - Counterbalanced by the greatly reduced fan and
chiller energy
71 Reduced
nearly twice
14Total Energy Consumption
42 Reduced !
19 MWh
11 MWh
Fan
Pump
Chiller
15Conclusions
- Significant energy saving potential over 40
- Small SA quantity ? Fan energy reduction
- Total energy recovery ? Equipment size reduction
- Increased pumping energy
- Offset by reduced fan chiller energy
consumption - Real operation data of the pilot DOAS/CRCP system
pending ASHRAE DOE funding - More information http//doas-radiant.psu.edu
16 Questions?