Upload
others
View
1
Download
0
Embed Size (px)
Citation preview
Presented By: Bob Trivedi, P.E.
Elara Engineering
Seminar Highlights
Brief introduc5on of basic electrical engineering ….only the important stuff.
The design issues that mechanical engineers need to consider.
Keys to achieving a successful project in a 5me sensi5ve environment.
Coordina5on between the mechanical and electrical disciplines.
Formulas, Formulas, more Formulas Symbolic: E =VOLTS ~or~ (V = VOLTS) , P =WATTS ~or~ (W = WATTS) R = OHMS ~or~ (R = RESISTANCE), I =AMPERES ~or~ (A = AMPERES) HP = HORSEPOWER, PF = POWER FACTOR kW = KILOWATTS, kWh = KILOWATT HOUR VA = VOLT-‐AMPERES, kVA = KILOVOLT-‐AMPERES EFF = EFFICIENCY DIRECT CURRENT AMPS= WATTS÷VOLTS, I = P ÷ E, A = W ÷ V WATTS= VOLTS x AMPS, P = E x I, W = V x A VOLTS= WATTS ÷ AMPS, E = P ÷ I, V = W ÷ A HORSEPOWER= (V x A x EFF)÷746 EFFICIENCY= (746 x HP)÷(V x A)
AC SINGLE PHASE ~ 1ø AMPS= WATTS÷(VOLTS x PF), I=P÷(E x PF), A=W÷(V x PF) WATTS= VOLTS x AMPS x PF, P=E x I x PF, W=V x A x PF VOLTS= WATTS÷AMPS, E=P÷I, V=W÷A VOLT-‐AMPS= VOLTS x AMPS, VA=E x I, VA=V x A HORSEPOWER= (V x A x EFF x PF)÷746 POWER FACTOR= INPUT WATTS÷(V x A), EFFICIENCY= (746 x HP)÷(V x A x PF)
AC THREE PHASE ~ 3ø AMPS= WATTS÷(1.732 x VOLTS x PF), I = P÷(1.732 x E x PF) WATTS= 1.732 x VOLTS x AMPS x PF, P = 1.732 x E x I x PF, VOLTS= WATTS÷AMPS E=P÷I VOLT-‐AMPS= 1.732 x VOLTS x AMPS, VA=1.732 x E x I HORSEPOWER= (1.732 x V x A x EFF x PF)÷746 POWERFACTOR= INPUT WATTS÷(1.732 x V x A) EFFICIENCY= (746 x HP)÷(1.732 x V x A x PF)
The source of power for most buildings comes from the energy u5lity. Power is generated at the u5lity and then transmiced to the end users through an extensive distribu5on network.
The power that we typically u5lize is either 120V, 208V or 480V. Other voltages are delivered depending on the type of facility.
It is important to know what voltage is available before we begin selec5ng equipment.
WHERE DOES THE POWER COME FROM?.........
MAIN SWITCHGEAR
THIS IS WHERE IT ALL STARTS……..
PANEL LOCATIONS ARE IMPORTANT.
KEEP ALL MAJOR EQUIPMENT NEAR THE SOURCE.
MAINTAIN PROPER ACCESS.
SAFETY IS ALWAYS THE FIRST PRIORITY…..WATCH WHERE YOU PUT YOUR
HAND!!!
IMAGE OF A LIVE FRONT PANEL
IMAGE OF A CONBINATION STARTER
A MOTOR STARTER IS AN IMPORTANT COMPONENT BECAUSE IT ALLOWS US TO REMOTELY POWER A MOTOR (PUMP, FAN, ETC.) WHEN NEEDED, AS WELL AS POWER IT DOWN.
IT PROTECTS ITSELF FROM ELECTRICAL OVERLOAD AND SAVES SENSITIVE MACHINERY COMPONENTS FROM DAMAGE.
MOTOR STARTERS:
DISCONNECT SWITCHES:
DISCONNECT SWITCHES COME IN A VARIETY OF SIZES AND VARY DEPENDING ON THE APPLICATION:
• INDOOR • OUTDOOR • FUSED AND NON-‐FUSED • AUX. CONTACTS
Variable Frequency Drives
• VFDs ARE USED EXTENSIVELY TO CONTROL PUMPS AND AIR HANDLING SYSTEMS
• WE NEED TO CONSIDER OPTIONS:
INTEGRAL FUSED DISCONNECT CONTROLS INTERFACE FULL ELECTRICAL BYPASS
DESIGN CONSIDERATIONS
Some important design related issues that we need to consider :
What is the service size and voltage? What is the new load (equipment power)? How far are we from the nearest power source? Do we need EM power? Do I need any special power connec5ons? Who is responsible for misc. wiring, controls, etc.? Starter, Disconnect, VFD….?????.....Who provides?
Interes5ng Design Facts Ligh5ng load is typically 1 wac per square foot of building area.
Receptacle load is typically 1 to 2 wacs per square foot of building area.
HVAC loads are typically 5 or more wacs per square foot of building area!!!!
WHAT CAN YOU DO TO HELP THE ELECTRICAL ENGINEER AND SPEED UP THE DESIGN PROCESS??
THE ELECTRICAL ENGINEER IS WORKING AGAINST THE SAME DEADLINES YOU ARE. HERE ARE A FEW IDEAS TO HELP THEM COMPLETE THEIR DESIGN WITHOUT THEM HAVING TO FALL BEHIND.
1) Layout the loca5ons of the major HVAC equipment. 2) Provide load data (even good es5mates) ASAP! 3) Coordinate who provides disconnects, VFDs etc. on the front
end. 4) Discuss any misc. components, sensors, wiring that needs to
be addressed by the contractors. 5) Don’t forget that some equipment needs more than one
power feed (lights, misc heaters, control circuits, etc.). It is not always a single point connec5on.
6) Review safety devices, controls circuits, equipment opera5on.
7) Provide final equipment cut sheets as soon as the they are available with wiring diagrams…..always the wiring diagrams!
8) Listen to the Electrical Engineers concerns…….we can avoid major issues this way.
How do you improve the process?
Project task list
Coordina5on Schedule
Communica5on
Project Task List :
• Details all required tasks that need to be completed by each discipline
• Helps to track design progress
• Indicates comple5on percentages
• Helps to focus acen5on on major design items that affect other disciplines
Coordina5on Schedule:
• Details responsibility between contractors
• Details what items are to be furnished under each contractors scope
• Helps to focus acen5on on equipment and accessories
Summary • Iden5fy available voltages.
• Iden5fy new electrical loads.
• Iden5fy any special considera5ons (VFDs, EM, etc.)
• Involve all team members as early in the design process as possible
• Provide preliminary data to begin the electrical design process as early as possible, then provide final data as soon as it is available
• Coordinate contractor and engineer responsibili5es (i.e. who provides what)
• Communicate and adopt a project task list
QUESTIONS?
Project Task List
MECHANICAL % Complete Notes
Load Calculations
Input initial load info into Trace
Run Trace output on a space by space basis
Run energy calc in Trace
Run Energy Model
System Selections
Determine best system type to use
Geothermal
Hybrid geo/heat pump
Conventional
Equipment
Selection of AHU and Return Fan
Determine the quantity and location of AHU's, MAU's
Complete layout of supply and return ductwork (inc. roof)
Show major duct runs only
VAV boxes should be noted but not shown
Perform static pressure calculations
Confirm loads to determine fan cfm, hp, CC, HC
Toilet Exhaust Fan
Determine exhasut requirement for toilets/ Janitors closet
Select fans, cfm, hp
Determine location for exhasut fans: roof, ceilings
VAV Boxes
Provide sizing criteria based on cfm for contractor use
Diffusers, Registers, Grilles
Provide a general list of diffuser types and models per sapce
Pumps and Accessories
Select pumps for AHU and reheat coil requirements
Chilled water pumps
Pre-heat Pump
Ductwork
Finalize CFM requirements for all spaces/zones
Layout main supply and return ducts(avoid existing utilities)
Layout location of VAV boxes (accessibility critical)
Layout supply distribution from main to VAVs
Layout supply distribution from VAVs to diffusers
Layout return duct from plenum to RF
Verify pressure drop calcs and make adj. to AHU/RF as req'd.
Finalize diffuser selections and locations
Size, type, quantity and color
Coordinate locations with RCP, lights, arch ceiling effects
Layout exhaust ductwork for toilets and Janitor's closet
Verify pressure drop calc and adj fan static as req'd.
Prepare airflow diagram to represent system
Review fire damper requirements and locations
Return duct insulation requirements ?? - Review with Abbott
Piping
Verify existing pre-heat and re-heat capacities
?? Existing capacity to serve new AHU requirements
Additional HX capacity available if pressure is increased (60# to 150#)
Verify HX loads and capacities
Determine tie-in points for utilities
Chilled water loaction in lower mech room
Pre-heat location in lower level mech room
Re-heat location in lower level mech room
Humidifier Steam piping (15#) located in upper mech room
Determine pumping requirements
Chilled water needs pump
Pre-heat ?? (50% ethyl glycol - capacity and additional glycol)
Re-heat ?? - serves serves VAVs
Select pumps for above utilities as req'd.
Capacity
Head calculation
Type (base or in-line)
Location
Accessories (SD, TDV, pads, gauges, thermo, DP)
Distribution
Routing of chw, pre-heat and re-heat to AHU (and sizing)
Routing and sizing of re-heat to VAV boxes
Stm./cond to AHU
Determine required shut downs for utilities
PID - piping and instrumentation diagram for piping systems
Chilled water
Pre-heat
Re-heat
Steam and condensate
CV's, gauges, thermo, sizes, gpm, control devices, flow arrows
Determine conflicts between existing piping and new duct routing
Demolition, rearrangement and rerouting of existing piping
Plan drawings to have PS #s, pipie system tags, sizing, flow arrows
Details
VAV box connection (duct and piping)
Ductwork connection
Coil connection at AHU
Humidifier connection
Traps
Condensate
Steam condensate
Return Fan on roof
Penetrations
Exterior ductwork
Curbs
Toilet Exhasut Fan
Penetrations
Curbs
Exterior Duct Support
Pipe and duct hanging/ support details
Base mounted (in-line) pumps
Diffuser connection
2x2
Linear slot
Schedules
AHU
Return Fan
Toilet Exhaust
VAV Boxes
Reheat coils (VAV)
Control Valves
AHU (Masoneilan)
VAV (Siemens)
Humidifier (Masoneilan)
Humidifier
Diffusers, registers, grilles
Pumps
Steam traps
Fire Dampers
STRUCTURAL
AHU Pad or rails
Return fan roof support (curbs)
Return fan roof duct penetrations
Hot water heater wall supports
Toilet exhaust fan curbs
PLUMBING
Fixture cuts from Mark Tropinski
Faucet cuts from Mark Tropinski
Underground plumbing piping
Above ground piping distribution
Cold water
Hot water
Hot water return
Vent
Select electric water heater
Finalize location for HWH with Mark Tropinski
Layout piping
Isometric
Sizing of piping
Connection to existing sanitary
Connection to existing FW
2.5" valve at main RPZ
FW line size
Demolition of existing toilets
Plumbing details
Plumbing Schedules
Water fountains
Cuts from Mark Tropinski
CONTROLS
T-stat locations for VAV boxes
Open area stats are critical
Airflow measuring stations for AHU and RF
Fan mounted ??
ELECTRICAL
Determine power requirements
Workstations
Offices
Conference rooms
Fill line and workstations
Electric water heater
Water fountains
IT room (panels, filters, dedicated gnd.?)
Lighting loads
Review existing panels locations and determine main distribution
Panel location and quantities
Transformers
Lighting layout
Finalize fixtures
Check photometrics
Finalize fixture layout in RCP
277/480v panel requirements and placement
120/208v panel requirements and placement
Lighting controls
Square D control panel
Occupancy sensors
EM lights
Exit signs
Underfloor duct distribution
Layout for demo package
Transformer selcetion and sizing
Electric room layout
Electric room and IT room cooling requirements
Fire Panel
Smoke detectors
AHU
Space
IT room
Electric room
FIRE PROTECTION
Review existing piping and head layout
Determine space FP requirements
Hazzard
Head type
Head layout (coordination with RCP)
Piping requirements
Calculations
Zone Valves
Fire Panel interface
Reconfiguration of existing piping