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eHVAC: Wireless Modular Multi-Zone HVAC ControllerGroup 14

Michael Trampler EEJavier Arias EE Ryan Kastovich EE Genaro Moore EEOverviewHeatingVentilationAir ConditioningSome provide advanced features such as humidity control and CO2 monitoring/controlScheduling and adaptive set-points will allow the user to reduce the systems run time.Run time data logging will give the user a better understanding of the systems activities

MotivationIncreased cost of electricityGreat cost of commercially available HVAC controllers Limited feature set of commercially available HVAC controllers, especially web enabled controllers

ObjectivesAccurately read temperature and relative humidity both inside and outside building.System management through web applicationScheduling capabilities CO2 monitoring for a gauge of air qualityZone controlExpandable to multiple zonesWireless connectivity to RSMReduction of energy consumption due to scheduling and set-point controlSimple and easy installation with minimal wiring.

Project SpecificationsMain Controller Control up to 8 zonesWireless connectivity to RSM at a minimum of 30ftWeb InterfaceHost at least 5 users simultaneously Manage week long schedules for each zoneDisplay status of up to 8 zones simultaneouslyRSMTemperature 0.125CHumidity 5% relativeCO2 At least 500 ppm744 hours of battery life

System Block DiagramPlant Block Diagram00

Plant SpecificationsNeed to supply 24VAC to drive the different components

Be able to support up to 8 zones

Continuous uptime for 2 months

Heat PumpVarious types: single stage, multi-stage, variable compressor, variable fan, oil, gas, etcSingle stage heat pump very common in FLDesign to implement a multi-stage systemAir handler indoors, 2 compressors outdoors

Heat Pump ComponentsReversing Valve (changeover)Controls heating/cooling mode

2 Compressors Each compressor with has a fan

Fan (Air Handler)Automatic turns on when ever the whole unit is onON (continuous) on regardless of the state of the unit

Control (Hardware)74HC595 (from TI)8-bit serial input shift registerSerial or parallel outputVcc: -0.5V - +7VNeeds only 3 inputs: data, latch, and clockOutputs 0 Vcc (V)

11Control (Hardware) ContinuedMAC97 TriacConnected to 24VAC supply to drive the heat pump componentsCan handle up to 600V2V max gate trigger voltage0.66V typical trigger voltage

Heat Pump Control Schematic

Plant Block DiagramDamper ControlDampers act as a door for air to flow through ductsDampers come either N-O/N-CRequire 24VACUtilize normally open 2 position dampersMakes system modularAble to implement up to 8 zones74HC595 Shift Register8 outputs for 8 zonesMAC97 Triacs8 triacs for the 8 zones

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Damper Control SchematicBreakout BoardTo demonstrate the ability to control the different components, a demo board will be attached to the MCU

Consists of rectifiers for the AC voltage

Drives LEDs to simulate the different components

Main Control Unit (Hardware)Software control of the plant will be housed in the MCUSends 2 2-digit hex values to shift registersEach bit responsible for a single componentResponsible for gathering and parsing through data from the Remote Sensor ModulesCommunicates with RSMs through a wireless moduleTalks to wireless module via UART Communicates with Web App through CGI commands Stellaris LM3S8962 Microcontroller

System Block DiagramTemperature/ Humidity HardwareUsing a digital Temperature/Humidity Sensor from HoneywellHIH-6130Accurate to 4% RHOperates from 0-100% RHAccurate to .025 CSPI3.3V supply0.6-0.75mA current consumption

CO2 MeasurementTelaire T6004Ultra High Accuracy in DIR (Infrared)Digital SensorEfficient Power ConsumptionSensitive from 0ppm to 20,000ppmRequires 100mA at 5VHas SPI Interface

User InterfaceOne 1.8 inch TFT color display16 bit color resolution160 x 128 pixelsSPI interface2 push buttonsUsed for simple input

Wireless Communication SpecificationsMSP430G2553UART Connectivity to modulesCC110L Transceiver Anaren booster packFrequency Band: 779 928 MHz200nA sleep mode consumptionSPI connection between transceiver and MSPCreates single code base for wireless communications

System Block Diagram

Stellaris InterfaceModified lwIPhttpd (web server) implementation provided with Stellarisware.

Common Gateway Interface (CGI) adapter provided by Stellarisware sample code.

CGI Calls for polling and updating RSMs, and plant components.

Web App HostingStellaris LM3S8962BeagleboneGoogle App EngineClock Frequency50 Mhz720 MhzN/ARAM64 KB SRAM256 MB DDR2N/AStorage256 KB Flash + microSDmicroSDN/AEthernetYesYesN/AOperating SystemNoneLinuxN/AHTTP ServerC (Custom coded using lwIP)Apache/LighttpdN/AApplication ProgrammingCC/Python/PHP/Perl/JavaPython/Java/GoData storageCSVCSV/SQLDatastoreCost~$90 (dev board)~$90 (dev board)N/AEnd-to-End ConnectivityGoogle App EngineCloud computing: Platform as a serviceHosting on Google's infrastructureGoogle Cloud = Distributed resourcesNo need to manage serverApplication development:PythonJavaData storage: Google Datastore

Python/ JavaPythonJavaIs it Free?Free and Open SourceFree and Open SourceLearning CurveSimple SyntaxLacks Simple SyntaxDoes it need to compile?NoYesOther tools?Wide range of tools and librariesLarge range of librariesBuilt In Docs?YesNoScript?YesNoDifficulty of Implementation in the Google App EngineVery straight forward implementationNot very straight forward

Webapp2Lightweight frameworkBuilt into Google App EngineWSGI AdapterInterface between web server and web applicationAlso responsible for handling uncaught exceptionsJinja2 Templating EngineUsing a templating system we can dynamically generate portions of the HTML and embed special placeholders in the HTML files to indicate where the generated content should appear.RoutesHandle requests in the web application by dispatching handlers for different events (i.e. Display Zones, Display Readings, Schedule, etc.)

Webapp2 Handlers FlowchartAutomatic PollingWeb Application polls MCU every 2 minutes.

Requests status of Plant and RSMs via CGI call.

Processes received information (JSON format):Update system readingsChecks if schedule needs to run

Sends updates to plant and RSMs via CGI calls available in Main Control Unit.

Google DatastoreHorizontally distributed database based on Google's BigtableManages very large sets of structured dataAllows for scaling of applications as they receive more trafficObject datastore Objects are called entitiesEntity kinds (classes) Modeled in Python or JavaSupports atomic transactionsPython and Java APIsGoogle Query Language: flexible but not as much as SQL

Data ModelsEvery entity has its own unique key propertyImplicitly created by the App Engine during entity creation.Includes the entity kind and a unique numeric ID that is automatically assigned.

System Block Diagram

Operating EnvironmentDevelopment Platform:Google App Engine

Backend Programming Language:Python

Primary Client-Side Scripting Framework:jQuery Mobile (JavaScript)

Why jQuery Mobile?HTML5 and CSS3 CompatibilityWorks on both Android and iOSProfessional Layout for PC, Tablet and Mobile DevicesCompatibility with Firefox, Chrome, Safari and others

Allows for rich touch screen interfaces for mobile devices

jQuery Mobile InterfacejQuery Mobile API which resizes depending on the pixel size of the device which is perfect for mobile and Tablet devices.

A PC/ Tablet layout has the ability to display on both sides of the screen with a primary and secondary table structure

A Mobile layout will fit the menu options to the screen and upon user interaction will display the data PC/ Tablet Landscape View

Mobile View

Web App Use Case DiagramSchedulerStandard HVAC systems typically do not include embedded schedulers for their users

User will be able to adjust Set times, Fan Modes, System Modes and Set Points for specific zones in the system

Users will be able to adjust their scheduler for a week at a time

Coded in pure HTML/CSS/JS with Python backend

Output Power SupplyUse readily available 24VAC supplyMost commercial HVAC controllers use a 24VAC supply as standardOutput 24VAC for HVAC system controlThis 24VAC will drive the Breakout BoardControl will come directly from main board therefore no need for logic power

43Main Controller Power SupplyUse readily available 17V Laptop power supply5V switching regulator for logic level power3.3V LDO Linear Regulator

OKI-78SR-3.3DE-SW033LM2574MInput Voltage Range7-36V5-30V0-60VEfficiency75-90%83%80-95%Current1.5A1.0A1.5ACost$4.35$15.00$.2044RSM Power Supply RSM will use 4 AA batteries to supply unregulated powerA 5V regulator will supply power to the CO2 sensor3.3V regulator will be used for the sensors, the wireless communication and the main microcontroller

Testing

Web Application Testing

Web Application Testing

Web Application Testing

Project DistributionMichaelJavierRyanGenaroPlant Control5%15%5%75%RSM85%5%5%5%Database5%55%35%5%Web App5%35%55%5%PCB75%5%5%15%BudgetItemQuantityPrice (of each)Expected BudgetFinal BudgetSensor Microcontroller8$3.00$24.00$48.00Humid/ Temp Sensors2$15.00$30.00$60.00CO2 Sensors3$10.00$30.00$60.00Graphical Display Unit(s)6$12.50$75.00$75.00Input Peripheral Suite4$5.00$20.00$20.00RSM Power Supplies4$10.00$40.00$80.00Main Controller Power Supplies1$15.00$15.00$30.00RF Module6$15.00$90.00$180.00PCB1$70.00$70.00$140.00Main Controller1$60.00$60.00$120.00Grand Total$454.00$813.00Rapid degradation of Thermostat LCDsWeb App Handlers Redirect issuesCO2 Sensor Power Consumption very highAnaren Booster Packs requiring .2V higher than specifiedLack of Reliability from Wireless and SensorsIssuesQuestions?