Gregory Wolfe 2004 Senior Thesis Lighting / Electrical

Transcription

1 Electrical Depth The current electrical one-line diagram for the is a radial system with one switchboard with 21 panelboards off it. However, by redesigning the lighting systems in the gathering space, open office plan and worship space, the lighting loads on the panelboards will obviously be affected. For the first portion of the electrical depth, the lighting changes in the worship space will be analyzed to see if there were any changes in the overall electrical scheme. (A) - Switchboard (2000A, 480/277V, 3 phase) (B) - Panelboard (400A, 208/120V, 3 phase) (C) - Panelboard (400A, 208/120V, 3 phase) (D) - Panelboard (800A, 208/120V, 3 phase) (E) - Panelboard (225A, 208/120V, 3 phase) (1) - Panelboard (225A, Receptacle Panel) (2) - Panelboard (100A, Dimmer Panel) (3) - Panelboard (100A, Lighting Panel)

2 The worship space s original electrical layout places 3 circuits on to the lower level lighting panel (HLL2) and has lamps on three separate dimmer panels. DR-#1 is a panel that holds all lighting for the theatrical stage. In the original plan, the lights to the left and the right of the worship space were also placed on this panel. DR-#2 and DR-#3 were created solely for the worship space lighting. Worship Space Lighting Circuits Panelboard Circuit # Number of Lamps Lamp Type Amps/Lamp Amps on circuit Voltage HLL2 2 6 MH MH MH DR-# DG DG DG DG DG DG DGE DGE DGE DGE DR-# DGE DGE DGE DH DH DH DGE DGE DH DGE DGE DR-# DG DG DG DG DG DG

3 Recalling the new worship space design, there were 18 circuits created for lighting. Those circuits are as follows: Circuit # Number of Lamps Lamp Type Amps/Lamp Amps on circuit Voltage W1 7 Pendant W2 7 Pendant W3 11 Uplights W4 12 Uplights W5 12 Uplights W6 11 Uplights W7 8 Lower Cove W8 7 Lower Cove W9 8 Lower Cove W10 7 Lower Cove W11 7 Upper Cove W12 7 Upper Cove W13 7 Upper Cove W14 7 Upper Cove W15 5 Downlights W16 5 Downlights W17 5 Downlights W18 5 Downlights All circuits are under 16A, so they can all use 20A circuit breakers. Because they are all on 120V, W3 through W6 can be placed on Dimmer Panel #1. The remaining circuits can all be moved on to panel HLL2, a 277V panel with a 100A breaker. (New and revised HLL2 panels can be found on page 64.) As a result of this rearrangement, Dimmer Panels #2 and #3 can be eliminated. By eliminating Dimmer #2 and the original lamps on Dimmer #1, and by adding the new lamps to Dimmer #1, it is possible that the load on the distribution panel will be affected. To examine this, a summation of the loads on all relevant boards (LRL2A, LRL2B, LRM2A, LRM2B and Dimmer #1) is necessary

4 LRL2A: Receptacles + Monitoring System + Track Lighting Receptacle Loads: 138 receptacles x 180 VA = VA VA x 1.0 pf = VA x 0.5 pf = 7420 Total Receptacle Load = VA Monitoring System: 20A x 208 V = 4160 VA Track Lighting: 20A x 208 V = 4160 VA Total Load = 25,740 VA Current = kva / (sqrt(3)*.208kv) = 71.4 A LRL2B: Receptacles + Toy Sanitizer + Water Softener + Gas Water Heater + Plumbing Pump + Washer/Dryer + Refrigerator Receptacle Load: 20 receptacles x 180 VA = 3600 VA Toy Sanitizer: 30A x 208 V = 6240 VA Water Softener: 20A x 120 V = 2400 VA Gas Water Heater: Plumbing Pump: 20A x 120 V = 2400 VA 20A x 120 V = 2400 VA Washer/Dryer: 40A x 208 V x 1.25 (largest motor) = VA Refrigerator: 20A x 208 V = 4160 VA Total Load = 29,520 VA Current = kva / (sqrt(3) x.208kv) = A LRM 2A: Receptacles + Exhaust Fan 5 + Cabinet Unit Heater 2 and 3 Receptacle Load: 98 receptacles x 180 VA = VA VA x 1.0pf = VA 7640 VA x 0.5pf = 3820 VA Total Receptacle Load = 13,820 VA Exhaust Fan 5: 20A x 120V x 1.25 (largest motor) = 3000 VA CUH 2: CUH 3: 20A x 120V = 2400 VA 20A x 120V = 2400 VA Total Load = 21,620 VA Current = 21,620 VA / (sqrt(3) x.208kv) = 60 A

5 LRM 2B: Assuming full load on eight 20A circuits 8 x 20A x 208V = VA Current = 33,280 / (sqrt(3) x.208 kv) = 92.5 A Dimmer #1: Plug Strips + Plug Boxes + Worship Wash Lights (Assuming plug strips are equiv. to 4 receptacles and plug boxes are equiv. to 2) Plug Strips: Plug Boxes: 74 strips x 2 x 180 VA = VA 16 boxes x 180 VA = 2880 VA Total Plug Load = VA Current = kva / (sqrt(3) x.208 kv) = 82 A Lighting Load: 57.5 A Total Current = A Total Current from all Panel and Dimmer Boards = 446 A Analysis Because the total current from all panel and dimmer boards is 446A, the smallest circuit breaker available for LDL2 is 600 A. Even though the future theatre company switch still needs to be added, the 154A discrepancy between the circuit breaker and the loaded circuit should cover this. Because the circuit breaker is sized at 600A, the panelboard itself should be sized at 600A. Assuming a THW Copper wire at 75C temperature rating, two conductors carrying four #350 kcmil wires should be specified. (from NEC table ) From NEC table C8, a 5 conduit can hold 8 #350 kcmil wires. The transformer should be sized at 225 kva. (Transformer = sqrt(3) x 208V x 600A = 216 kva) HLL2A How will the new lighting in the worship space affect the size of panel HLL2A? On the next page is an original and revised panel schedule. Existing Lighting (Circuits 1-14) = 8134 W Boiler = 20A x 120V = 2400 VA New Lighting = 42W Total Panel Load = VA Current = / (sqrt(3) x.480) = 12A The current is clearly low enough to continue to use a 100A circuit breaker and 100 A panelboard

6 Original Panelboard Redesigned Panelboard

7 The second portion of the electrical depth will focus on emergency lighting. Currently, backup lighting is provided by battery packs with inverters. Although this system works fairly well, the is large enough to potentially replace the backup batteries with a generator. This generator would then not only backup the emergency light fixtures, it would also act as backup for fire alarms, fire pumps and elevators. However, in order to consider this change, a brief cost comparison must be performed. There are 194 battery packs in the. These battery packs include those on fixtures in the redesigned rooms: the gathering space, open office plan and worship space. According to R.S. Means, battery packs cost approximately $80. Thus, the approximate cost of the current system (not including maintenance) is: $80 = $15, x In order to determine a cost for the proposed generator, it is first necessary to determine just how much load will be on this generator. To calculate this, I added the lighting loads of all fixtures currently on battery packs to the lighting loads of all parking lot fixtures. This gave a total lighting power load of 30,329 W. The one elevator in is 63 hp. The building s fire pump is 25 hp, or kw. As a rule of thumb, the power load on the generator corresponds to the original power load as follows: 1 kw of lighting = 1 kw of Generator Capacity 1 hp of motor = 2 kw of Generator Capacity 1 kw of fire pump = 3 kw of Generator Capacity Therefore, the approximate capacity of the generator needed is: Lighting: Motor: Fire Pump: 30.3 kw 126 kw 56 kw Total Capacity = kw Because gas operated generators only go up to 185 kw, a diesel engine generator will be used. According to R.S. Means, in 2000 the total cost for a 250kW diesel generator (materials, labor and equipment) is $44,925. Adjusted for 2002, this equals: (100/90.9) * 44,925 = $49,422 System Cost Battery Backup (current system) $15, kw Diesel Generator (new system) $49,422 Difference -$33,902 Naturally, with a $33,902 difference, it is not worth it to switch to a diesel generator at this point. Even though, the battery backup costs don t include continued maintenance and battery replacement, the long term benefits of using a generator don t justify spending $33,902 for a

8 generator (especially when the $49,422 does not include longer feeder costs and probably a new panelboard). However, plans for the campus include the construction of six more buildings. When these buildings are constructed, the construction of a generator for the whole Westwood campus seems very beneficial