Hvac control and Feedback System 0 Group 2 Steve Jones Mathew Arcuri Elroy Ashtian, Jr
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- 5.5 Relays Testing
- 5.6 Relays Testing
- 5.7 Final Specifications and Requirements
- 5.7.2 Final Requirements
5.4 EnvironmentThe testing environment for the bulk of the development and testing time will be spent inside the Senior Design II lab located in the Engineering Building 1 on the University of Central Florida (UCF) main campus. If other components that we purchase require more workspace to develop then our group will utilize selected off campus locations in order to construct our HVAC control system. Traveling to different sites to test out different systems supplied by the project sponsors might be necessary. When placing our HVAC control system's remote sensor unit outside in an open environment exposed to the weather elements, it must have a cover to protect its electrical components in case of bad weather causing heavy amounts of precipitation or sever conditions. Any facility chosen for us to conduct our development or testing must have a high standard of safety and procedures in case of electrical fire due to a wire being shorted or overloaded with too much current as well as good grounding which serves the dual purpose of keeping group members alive and preventing equipment from being destroyed should there be a short. A good ground also prevents damage by providing a proper ground for the group members themselves while using anti-static wrist guards to prevent electrostatic discharge on sensitive equipment. Furthermore many if not all of our components are Restriction of Hazardous Substances Directive (RoHS) compliant which is good should any fire happen we and others in our immediate area will not be exposed to as many toxic materials via pollutions of the air in the testing environment. Also upon disposing of destroyed parts the components will leech fewer chemicals into the environment. In this regard our testing environment is really everyone’s environment and as such we take our conduct there and its implications seriously. 5.5 Relays TestingFor testing the BeagleBoard we will follow essentially the directions in the manual. We will need as USB OTG style cable or a 5v 2A power supply, an LCD monitor with DVI input, a mouse, a keyboard, a flash memory card at least 4GB in size and a personal computer with both a Linux distribution installed - preferably Ubuntu- and an RS-232 port. We will format the flash memory card on the Linux personal computer with the proper Unix file formatting required for the drive which is ext2. We will then place the test software included on the BeagleBoard’s website which tests the basic functionality of the device on the flash memory card. We will then take the flash memory card and insert it into the BeagleBoard. We will then connect all other external devices needed, LCD screen, mouse, and keyboard except the power. After double checking the connections we will then power on the device by plugging it in to the USB OTG port. Upon boot we will run a series of diagnostic tests that will make sure all features of the board are working. 5.6 Relays TestingThere are multiple relays coming out of the main control board, and it is necessary to be sure that the units are working more than just checking for the familiar click of a relay switching. All these relays could be hooked up to an oscilloscope or multi-meter for testing 24VAC, but for demonstration purposes a different approach will be used. It is impractical and too costly to hook up two air conditioners and a heater, so those three systems will be represented by lights powered by the 24VAC output. The fan output will be connected to a smaller fan that will run on 24VAC for effect. An electronic damper will be purchased and connected to one zone to show that the system can more than power that device. The mood scent will be implemented for the scope of this project as engineering a typical department store scent disperser to be connected and functional on 24VAC. 5.7 Final Specifications and Requirements5.7.1 Final SpecificationsBased on meetings with our sponsors, we have been able to produce a set of specifications to model our Efficient HVAC Control and Feedback System with. The final specifications we have been able to construct through our research and design work have come out very similar to our initial specifications. We realized the for any specification whether it be for a sensor or control unit that there was a vast amount of choices from many vendors and suppliers which made any requirement of the system possible but with detail research of the alternatives. We could have spent years researching and deciding which parts were the best to choose. There were many parameters to consider which parts which varied from ease of use, availability, and cost. These specifications are considered final, but there is the odd chance that change will have to occur due to any number of reasons, and our varied research in the many subjects above will prove to be valuable as a change of parts or direction won’t immediately change the impact of the use of the product. The overall cost of the system built with these specifications will not be indicative of the cost of building a final production system as much of what we are using is for development. Often development boards accrue a much higher cost. The final specifications we have come up with for the Efficient HVAC Control and Feedback system are listed below in both table 16.
Table System Control Specs The two microcontrollers will handle all the real time information and interaction with the electrical components. The main microcontroller, while much less powerful than the ARM unit, will provide the instruction set for our system. The secondary controller is used to transmit the temperature and humidity data wirelessly. Their specs are given below in Table 17.
Table Final Microcontroller Specs The main microcontroller that is used in the design requires a supply voltage of 3 – 3.6 V in order to be powered on. It has 85 programmable I/O pins that will be used to support control relays as outputs. It has 2 SPI ports, 2 I2C ports, and 2 UART ports that will be used for interfacing with other components in the main control unit. The 256k bytes of on-board flash memory will be used to store the programming for the decision making logic and the 512 bytes RAM will run the application to send data to high level control unit. All programming for the main microcontroller will be done using the C language. The secondary microcontroller that is used in the design requires a supply voltage of 1.8 – 3.6V in order to be powered on. It has 1 SPI port and 1 I2C port that will be used to communicate with a sensor and the ZigBee chip onboard the remote sensor unit. The programming will be stored in the 4K bytes program memory and the 512 bytes RAM will run the program. All programming for the secondary microcontroller will be done using the C language 5.7.2 Final RequirementsThe sponsor for our project, AC3 Development Group, LLC provided the basic requirements for our project and allowed for added flexibility with the removal or addition of specifications based on our time constraints. At a high level, the basic requirements of the system are very simple and obtainable based on a the first version of the HVAC Feedback and Control System. The system is required to sense the temperature and relative humidity from inside and outside a structure (residential or commercial), read the settings determined by the user (inputted via LCD touch screen interface), and make an intelligent decision to satisfy the preset temperature and relative humidity levels in the most effective and energy efficient manner. All of these features were implemented in the first version of the system and is also important in this iteration. For this iteration of the system, it is required to have a scheduler to store user submitted entries of desired temperature and humidity settings at specified interval throughout a 7 Days week span. An authorized technician should also be able to log into the system and adjust the available HVAC components and the features of the application along with perform firmware update. The system is intended to either be retrofitted to an existing HVAC system, or to be installed in a new building but only require essentially the normal wiring that would be installed for a normal HVAC system. In order to avoid running additional wire not normally associated with an HVAC system inside either an existing structure, or a newly constructed building the temperature and relative humidity measurements taken outside must be transmitted to the Main Control Unit wirelessly. In order to achieve wireless data transmission, the sensor must make its readings; pass the data to a microcontroller which, in turn, must pass the data to a wireless chip that will communicate with another wireless chip on the Main Control Unit which will send to and receive data from the High Level Control Unit. The wiring for the air conditioning units to be controlled is already installed in the building, and therefore controlling the power relays to turn the air conditioning units on and off can be done via wire. AC units typically run on 240 Volts AC. To get this voltage to the units, a power relay must be switched to essentially complete a circuit connecting the units to the main 240V power supply from the building. Out control system is required to switch appropriate relays to send 24 V to the 240 V power relays which turn on the AC units. To control each unit, a signal must be used for each of the following functions of the unit. The HVAC components of an air conditioning system are, 1st Stage Heating, 2nd Stage Heating, Blower / Fan, Compressor, Reversing Valve, and 24V Common. The American Society of Heating, Refrigerating, and Air-Conditioning Engineers set standard naming and color coding standards for these functions that we plan to follow in both our system design and the planned demonstration. Table 18 shows each HVAC Component along with its ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) Naming and Color Coding Standard.
Table HVAC Components and the Corresponding ASHRAE Naming and Color Standards The subsystem that controls new air flow into the building is required to control four dampers in the ducts of the HVAC system, and is required to be controlled wirelessly. These four dampers will control airflow through the ducts depending on user controlled settings via the touch screen. If a dehumidification unit is not integrated into the existing HVAC system at the time the Efficient HVAC Control and Feedback System is installed, it must also be controlled wirelessly. Directory: seniordesign -> sp2011su2011 sp2011su2011 -> Group 5 Spr-Sum 2011 seniordesign -> Senior Design II paper seniordesign -> Remote Touchscreen-Controlled Defense Turret Senior Design Documentation Courtney Mann, Brad Clymer, Szu-yu Huang Group 11 seniordesign -> Flight Performance Data Logging System seniordesign -> Amphibious vehicle seniordesign -> T-100 Watch Dog (Autonomous Security Vehicle) seniordesign -> Ehvac: Wireless Modular Multi-Zone hvac controller Group b javier Arias Ryan Kastovich Genaro Moore Michael Trampler seniordesign -> Table of Contents Executive Summary 2 Download 0.56 Mb. Share with your friends:
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