Objectives Review and Groups for Project 1 Start ELECTRICAL SYSTEMS - Review/Learn Fundamentals

Project Assignment 1 Cover the previous course material Homework assignments Reading assignments Similar to a real-world project You will have similar one in ARE 465 (Integrated design course)

Project Assignment 1 Design the environmental system for large building Project that you will have next year Simplification (one zone for calculation) Show the logic for zoning Select the heating and cooling fuel Select the heating and cooling source Select and size the HVAC system Size the Cooling Coil and analyze the process in AHU

Project Assignment 1 5 Groups (teams) – 5 Different assignments Group 1: - Sadie Wilson - Cullen Vance - Ariel Creagh - Stephen Mathai - Brian Hertz Group 2: - Troy Thompson - Christopher Lawrence - Kevin Carbonnier - Alan Del Olmo Group 3: - Chris Krenek - Amanda Hawkins - Benjamin Ash - Robert Chamra - Jocelyn Citty Group 4: - Brian Burcham - Justin Barrett - Patrick Gorman - Kenneth Greaves - Margaret Lawson Group 5: - Elson Wang - Matt McCarthy - Parker Thompson - Jill Monholland - Hannah Romanie

Where are we going? HVAC Electrical systems Lighting technology and design Acoustics (at the very end)

Specific Objectives List and define terms associated with electrical design in buildings Calculate electric quantities with Ohm’s Law and Kirchov’s Law (review) Calculate electricity costs for residential and commercial buildings Major emphasis – how do you begin designing an electrical system?

Applied Electrical Concepts Use terms to describe building electrical system AC vs DC ch. 10 Ohm’s and Kirchov’s Laws ch. 10 Power vs. Energy ch. 10 Resistors, Inductors and Capacitors ch. 10 Power Factor ch. 10 Single-phase vs. Three-phase ch. 10 Grounding ch. 11

What is the NEC? National Electrical Code National Electrical Corporation A kind of cookie National Energy Code A manufacturer of plasma televisions

Electrical Codes National Electrical Code (NEC) Focus on safety Prepared by National Fire Protection Association Part of the national and state building codes Library website Tao and Janis - Section 13.7 Focus on safety

AC DC Direct Current (DC) Alternating Current (AC) Sign matters Alternating Current (AC) Switching polarity Which are the following? Photovoltaic solar cell Automobile alternator Household outlet Outlet in ECJ Battery High voltage lines

AC terms Frequency, f [Hz] Resistor [Ω –ohm] Wall outlet? Fluorescent light? Clock? Electric resistance heater? Resistor [Ω –ohm] Capacitor (plates separated by dielectric) Inductor (coil of wire) Transformers

Why use AC? Easier to generate 4/15/2019 Why use AC? Easier to generate Able to use inductors and capacitors in meaningful way Voltage changes much easier Lower distribution losses ARE 346N

Voltage and Current Voltage (potential difference) E or V [V] R [Ω] Voltage (potential difference) Units? Symbols: V, E or U Current (electron flow) Symbol I

Transformers Change - Voltage [E] and - Current [I] Across a transformer I1E1 = I2E2 Es/Ep = Ns/Np

Ref: Tao and Janis (2001)

Ohm’s and Kirchov’s Laws V = IR or E = IR (E = energy potential [V]) P = EI = I2R ∑I = 0 for a node ∑E = 0 for a closed loop 4) Are these for : A) AC or B) DC or C) both? I [A] E [V] R [Ω]

Single-Phase vs. Three-Phase For three phase: P=√3 E I Ref: Tao and Janis (2001)

Why do commercial buildings use 3 power? Requires fewer wires Higher motor efficiency Requires bigger wires Smaller space requirements

Why Three-Phase? Larger loads Smaller wire sizes (because higher voltages) P = EI = I2R= E2/R (E = IR) More efficient use of neutral wire 3 needed for efficient operation of equipment

Power Factor Difference between power supplied and power that does useful work “working power” P=E I cos θ θ is the phase difference between current and voltage For circuits that contain reactance (Inductor and Capacitors) For three phase P=√3 E I cos θ Commercial buildings pay for power factor.

Electricity Billing Electrical Use (energy) Peak Demand (power) Power factor Which is largest portion of residential bill? What about for commercial buildings? http://www.austinenergy.com/About%20Us/Rates/Commercial/index.htm

Example: September cost of Electricity for ECJ Assume ECJ is 120,000 ft2 and that it needs, on average, 8 W/ft2 for 8 hours a day, 6 W/ W/ft2 for 4 hours a day, and 4 W/ft2 for 12 hours a day Use Austin Energy Large Primary summer service rate 1.5¢/kWh, 12.60 $/peak kW/month Assume no power factor charges

Solution large primary service $/kW $/kWh Daily $ 12.60 $ 0.015 hours $ 12.60 $ 0.015 hours kW kWh 8 960 7680 demand $12,096.00 4 720 2880 energy $ 7,344.00 12 480 5760 TOTAL 16320 Total $19,440.00

Other Pricing Strategies Time of use pricing Becoming more common for residential and commercial Electricity cost related to actual cost Requires meter Interruptible pricing Utility can shut off electricity for periods of time

Summary Know about NEC Compare DC and AC Calculate current/voltage across a transformer Describe 3-phase power and compare to 1-phase List reasons for using 3-phase List and explain components of electrical billing Calculate commercial electricity bill

Reading Assignment Tao and Janis: Chapter 10 Chapter 11 Sections: 11.1- 11.3 (including 11.3)