Zero general illumination (ZGI): an energy, comfort, and lighting performance evaluation using an energy simulation model for sustainable office building design PLEA’99 Brisbane, Australia 22-25 Sept 1999 by Larry O. Degelman Visiting Guest Professor Nagoya University
[email protected] 24 Sept 1999
© L.O. Degelman, Sept 1999
Objective
To investigate the viability of using zero general illumination (ZGI) in a critical seeing environment (design and drafting room), with specific reference to: – – – – –
Seeing conditions Lighting power densities Life-cycle cost economics Integration with motion sensors Comfort hours
Procedures Course
assignment Simulate a case study building (with a conventional lighting design) Simulate with ZGI and daylight Simulate with motion sensors
Course assignment (27 grad students) Arch 633, Env. Controls, Fall semester 1998
1. Calculate number of luminaires to provide 550 Lux in a 10x13-meter office module w/ 12 desks. 2. Calculate the resulting lighting power density. 3. Perform annual energy and cost simulation for lighting & HVAC 4. Design indirect lighting scheme to provide 110 Lux throughout and 440 Lux additional at each workstation. 5. Repeat annual energy simulations and compare energy and life-cycle cost results to no. 3 above.
Student project results
Student’s simulation results
Student’s LCC comparison results
Summary of student results Recessed fluorescents (base case): LPD = 15 W/m2 (ASHRAE Std 90.1 = 17 W/m2) Indirect lights w/ task lights (new design): LPD = 5.9 to 9.36 W/m2 Annual energy savings = 36 to 45% Life-cycle cost savings (20-yr life) = 23 to 35%
Case study building
5th floor office plan
BRW Architects office interior
Case study typical workstation
Adjacent conventional office lighting
Case study building Area
= 300 sq.m. No ceiling lighting fixtures Indirect LPD = 4.95 W/m2 Task LPD = 3.55 W/m2 Total LPD = 8.5 W/m2 (ASHRAE
90.1 LPD = 17 W/m2 )
BRW office plan sketch in Ener-Win
Ceiling-mounted motion sensors
Lighting pattern for 5.5 days
Monte-Carlo on-off simulation model. For any one minute, lights turn on, If Oncycle > 1 minute, then if – Rand(1) < prob/[1+(1-prob)*(Oncycle^0.9)] – Lights stay on for “Oncycle” minutes. If
Oncycle = 1 minute, then if
– Rand(1) < prob – Lights on for just 1 minute. Else
lights are off.
Life-Cycle Cost PROJECT ECONOMIC LIFE ASSUMED IS 20.0 YEARS. TOTAL $/Sq.m. ------------------CONSTRUCTION $ 8787243. 371.94 LIGHTING 549203. 23.25 HVAC 1114774. 47.19 WALLS 846832. 35.84 WINDOWS 57092. 2.42 ------------------ -----TOTAL 1ST COST $ 11355143. 480.64 PRESENT WORTH OF FUTURE ENERGY COSTS GAS 444815. 18.83 ELEC 2260369. 95.68 MAINT 621831. 26.32 --------------- --------TOTAL PW OF O & M 3327015. 140.82 -----------------------TOTAL PRESENT WORTH $ 14682159. 621.46 ------------------------
Discomfort hours > 26C 3000 2500 2000 1500 1000 500
Texas Brisbane Nagoya ZG I
MS ZG I&
Co nv
en
tio n
al
0
Lighting option results
350
An. En. (MJ/m2)
300
Tot.LCC (/m2)
250
Tot.1st Cst (/m2)
200
HVAC Cst (/m2)
150
An.Op.Cst (/m2)
100
An. Htg (MJ/m2)
50
An. Clg (kWh/m2)
Lighting Option
MS
An. Ltg (kWh/m2)
Indirct
Conv.
0
LCC results in 3 cities 350 300 250 LCC/sq.m in 200 local units 150 100 Nagoya
50
Brisbane
0 Conv.
Texas Indirct
Lighting Option
MS
Conclusions:
Office LPD can be 8.5 W/sq.m. in critical seeing areas (183 Lux general to 1100 Lux on task) This is a reduction of 50% from ASHRAE 90.1 recommended value of 17 W/sq.m. Annual lighting energy savings in range of 36 to 45% in spaces where indirect lighting is applied 20-yr LCC savings of 10% to 13% for indirect lighting scheme and 17 to 22% for motion sensors. Comfort hours improved by 10% in climates evaluated for non air-conditioned spaces.
Acknowledgments
BRW Architects for their permission to take measurements in their office space and CIRSE lab at Nagoya University for their support during the analyses and writing phases of this work.
Building performance simulation using ENER-WIN software. Download
at Web site: http://taz.tamu.edu/~energy/enerwin.html
Contact:
–
[email protected] –
[email protected] 