A Home Energy Management System for Demand Response Applications US-China Workshop: Smart Grid Research Opportunity Identification Nanjing, China Dr. Manisa Pipattanasomporn Associate Professor, Virginia Tech - Advanced Research Institute May 15, 2014
What is the Smart Grid? Short Answer: Smart Grid = Electric Grid + IT Normal Phone Smart Phone 2 Credit: Prof. Saifur Rahman, Virginia Tech
Starting and End Points of a Smart Grid From Generator to Refrigerator Power Plant Transmission Distribution Home Business End-use Appliances Customer Systems 3 Credit: Prof. Saifur Rahman, Virginia Tech
Need for Demand Response (DR) To shave peak demand, which would otherwise be met by peaking generators that run only several hours a year. Probability that peak loads exceed 16,000 MW is only 5% of the Ime Peak load of 19,140 MW 4 3,140 MW or 16.5% of peak load
VT s DR Concept Grid operator Step 1: Grid operator determines the amount of load (MW) to be shed. SubstaIons SubstaIons Step 2: The load shedding amount is allocated among substaions, feeders, and buildings. Step 3: Perform DR at homes or buildings ResidenIal customers Commercial customers 5 5
Home Energy Management (HEM) VT s HEM Concept: External control signal from an uility Water heater (4-6kW) Clothes dryer (4-6kW) AC unit (2-3kW) HEM Unit Demand limit (kw) Gateway DistribuIon board & meter Electric vehicle (3.3-16.8kW) Load Controller Data communicaion & control signal 6 The proposed HEM provides customers a choice to decide which appliances to control based on their priority and customer preference.
Example of Load Priority and Preference Settings & DR Strategy by Load Type Load Water Heater (WH) Space cooling (AC) Clothes Dryer (CD) Electric Vehicle (EV) #1. Priority sepng 1 2 3 4 #2. Preference sepng 110-120 F 76 F (±2 F) Not to exceed 85 F Finish the job by midnight Fully charged by 8AM 7
8 HEM Algorithm
HEM System Installation @ ARI External control signal from a utility PC with embedded HEM algorithms ZigBee coordinator Temp. set point Room Temperature V, I, W, pf ZigBee- enabled load controller V, I, W, pf ON/OFF Portable AC Electric 9 baseboard heater#1 (represent WH) Electric baseboard heater#2 (represent EV) Hair dryer (represent CD) 9
Electrical Power Ratings of Loads used in the Experiment & Scale Factors Actual load used in the experiment Portable AC Power rarngs 560W @ 115V Household power- intensive load Power rarngs Scale factor Central AC 2.3kW 3.8 Baseboard heater#1 590W @ 208V Electric water heater 4.5kW 7.6 Hair dryer 1.875kW @ 110V Clothes dryer 4.0kW (M=0.3kW) (H=3.7kW) 4.6 Baseboard heater#2 590W @ 208V Electric vehicle 3.3kW 5.6 10
Results of the Demand Response Demonstration No DR w/ DR (8kW limit from 17:00-20:00) Water heater Water heater AC AC Clothes dryer Clothes dryer Electric vehicle Electric vehicle Total House ConsumpRon Total House ConsumpRon 11
Load Electrical Measurements (V, I, PF, P, Q) DR event from 17:00 to 20:00 Electric baseboard heater#1 (represent WH) 208V, 590W Portable AC unit (represent AC) 120V, 600W Hair dryer (represent clothes dryer) 120V, M:180W H:690W Electric baseboard heater#2 (represent EV) 208V, 590W V I PF VA W 12
Implementation Issues Data errors No data CommunicaIon errors (package drop) Wrong data CommunicaIon errors (noise) Wrong data Microcontroller errors Round- trip delay between HEM and a load controller ~265msec @ 10 meters ~240msec @ 1 meter 13
Power Consumption Analysis CumulaIve annual energy consumpion for each selected component of a HEM is summarized below: HEM component Device Approx. Power ConsumpRon OperaRng DuraRon Annual energy consumpron (kwh/yr) HEM unit - Notebook - ZigBee Coordinator (data transmission at 1- min intervals) 21.9 WaYs (Monitor acive) HEM - 24/7 w/ 15.8 WaYs (Monitor sleep) monitor acive 1 min each day 139 kwh Load controller - Data capturing and processing module - ZigBee communicaion module - Control module (i.e. NC power relay - status: close) 1.4 WaYs (No data transmission) 1.7 WaYs (w/ data transmission) 24/7 5 seconds for each 1- min interval 12.5 kwh 14 14 - NC power relay (status: open) 1.3WaYs Depend on the duraion of HEM OFF command N/A
Hardware Prototype Developed @ ARI Front View Side View 12 15 12 6
Load Controller Prototype 16
17 Test Bench w/ four 240V Loads
Web Services Based HEM Provide customer interface to monitor & control appliances Allow an electric uility to perform DR without Advanced Metering Infrastructure (AMI). Take into account interoperability with other third- party systems 18
Summary Presented a hardware demonstraion of proposed Home Energy Management (HEM) System for residenial Demand Response (DR) applicaions Discussed real- world implementaion issues Analyzed power & energy consumpion of each HEM element 19
VT HEM Deployed at YTU Smart House Smart home @ Yildiz Technical University (YTU), Turkey VT s HEM Algorithm - Incorporated & tested HEM algorithm in YTU smart home environment 20
Thank You Dr. Manisa Pipattanasomporn Associate Professor, Virginia Tech, USA Email: mpipatta@vt.edu