Print this page 2010 Industrial HVAC Control Case, Part I
Thomas Mason, PE
Course Outline
We begin with a background statement, explaining why The Design Firm received the contract to do facilities design for relocation of a successful manufacturing process for a large international firm. Next is a brief review of the original plant HVAC system, made up of 27 fans. This is followed by a review of the original 1993 electrical design for control of the fans.
As part of the 1993 controls discussion, considerable attention is given to the different type of programmable logic controller (PLC) connections available and the advantages of each, along with the Code and safety compromises of each. In this section, the presentation of the 1993 design is shown, along with comments by the field installing crew and by the current author.
The discussion of the 1993 controls design is followed by interpretation of the engineering term, “as-built”. This is examined in terms of design changes during fabrication, field fabrication changes, certified as-built drawings and, finally, photographs of the finished product. This section is enormously interesting to engineers who sit at a computer screen all day. Their innocence will be destroyed.
The story moves to 2009, when plans are made to relocate the plant to a different country, with a different climate. The process and all machines are to remain unchanged. The facilities HVAC system, must, however be redesigned. Also, HVAC performance standards and fabrication standards have changed in the intervening 15 years.
The 2009 requirement for a different 29 fans is discussed, focusing on the difference in controls requirements, and only slightly, looking at the differing performance. The first relocation HVAC controls design (RELOC-1) was a straight upgrade of what was certified to be the as-built installation. However, later examination of the photographs forced a redesign to utilize the three large control cabinets, as fabricated. This produced RELOC-2. Finally (for Part 1 of this course), the client decided to replace the three large control cabinets with three personal computers running HMI (human machine interface). This leads us to RELOC-3, which is discussed, but not performed.
Part 2 of this course will discuss the PLC and HMI design approved by the Client and the system, as fabricated by the systems integrator.
The course includes
a multiple-choice quiz at the end, which is designed to enhance the understanding
of the course materials.
Upon completion of this course, the student will be able to:
- Correctly use the terms, “exhaust fan,” “supply fan” and “make-up air unit” with an HVAC designer or controls contractor;
- Understand the need for a motorized damper on a fan;
- Understand the operation and wiring of a motorized damper;
- Understand the components which constitute a complete make-up air unit;
- Understand enough of the internal controls of a make-up air unit to add external alarming of critical functions;
- Recognize the special controls requirements of a cooling tower fan, supply pump and return pump and the alarms necessary;
- Understand the power and controls requirements of a large air compressor;
- Prepare a preliminary design for monitoring of process gasses, including sulfur dioxide;
- Support the justifications presented for three large panels and a plc for the 1993 design;
- Support the justifications presented replacing the large panels with three personal computers in 2010;
- Participate in the concerns introduced by personal computers in critical industrial controls;
- Read relay ladder logic in both physical and plc form;
- Check relay ladder logic for compliance with safety requirements and standard form;
- Explain the limitations of Hand-Off-Auto selector switches and Start-Stop pushbutton;
- Understand the trade-offs between isolated- and common- input and output cards; and
- Explain the benefits of a graphic touch-screen operator interface terminal when using text.
Intended Audience
This course is intended for electrical design engineers who do not work daily with HVAC controls. It will be of value to HVAC designers who do not have direct knowledge of the electrical requirements that make their systems work. It will be of value to design and project managers who need to be able to ask the hard questions. It will be of value to engineering construction services personnel who must make last minute changes to get the systems to work.
Benefit to Attendees
The value provided by this course is in introducing concepts to persons who have not encountered them previously and to provide confidence in understanding to persons who follow previous examples but don’t understand the choices available.
Course Introduction
In 1993, The Design Firm (TDF) received a contract to prepare construction documents for a proprietary manufacturing process at a remote location of Large International Company (LIC). The Design Firm worked well with Large International Company and when LIC decided to relocate the process, intact, to a different country, they again contracted TDF for construction documents. Because the process is proprietary and subject to trade secret laws, TDF is very careful to conceal process details when bidding the facility design. Please join a brief review of the 1993 HVAC controls design and the 2009 relocation. This part of the course stops when LIC makes a substantial scope change for HVAC controls. Part II will finish the story.
Course Content
In this lesson, you are required to download and study the following course content:
2010 Industrial HVAC Control Case, Part I
Please click on the above underlined hypertext to view, download or print the document for your study. Because of the large file size, we recommend that you first save the file to your computer by right clicking the mouse and choosing "Save Target As ...", and then open the file in Adobe Acrobat Reader. If you still experience any difficulty in downloading or opening this file, you may need to close some applications or reboot your computer to free up some memory.
Course
Summary
This course presented representative excerpts from the 1993 HVAC controls design for a medium sized manufacturing facility. The form and content of the design material was discussed in detail, from both theoretical and practical viewpoints. An attempt was made to be professional and objective. For a more personal report on the same material, investigate the PDHonline audio version of the course.
Related Links and References
For additional technical information related to this subject, please visit the following websites or web pages:
HVAC
http://en.wikipedia.com/wiki/HVAC
Exhaust Fans
http://www.industrialfansdirect.com/IND-FA-EF.html?gclid=CJnBnpH7i58CFQ4MDQodNEtIhg
Supply Fans
http://www.industrialfansdirect.com/IND-FA-EF.html?gclid=CJnBnpH7i58CFQ4MDQodNEtIhg
Make-Up Air Units
http://www.greenheck.com/products/detail/55
https://www.rezspec.com/catalog-6_Heating_Cooling_Makeup_Air.html
Motorized Duct Damper
http://www.emwhouston.com/industrial-dampers.htm?kc=MIf0W&_vsrefdom=ppcgoogle&tsid=googleppc&ex=g8d5di-eep549-gd0y1w&gclid=CN6q4PeDjJ8CFQoNDQod1yyG2Q
http://www.hvacsolutionsdirect.com/product.php?productid=447&cat=0&page=1
Damper Actuator
http://www.greenheck.com/media/articles/Product_guide/actuators.pdf
http://www.greenheck.com/media/articles/Product_guide/actuators.pdf
Auxiliary Relays
http://hvac.functionaldevices.com/chartRelays.html
http://www.lineelectric.com/relays/index.html
Cooling Tower
http://www.lineelectric.com/relays/index.html
http://www.cti.com/whatis/coolingtowerdetail.shtml
Air Compressor
http://www.aircompressor.com/products.html
Toxic Gas Detector
http://www.draeger.com/US/en_US/products/gas_detection/portable/sensors/cin_draegersensor_xs.jsp?showBackButton=true
(This is the plug-in sensor for a comprehensive system.)
http://www.sensorelectronics.com/
SO2
http://en.wikipedia.com/wiki/Sulfur_dioxide
http://www.epa.gov/air/sulfurdioxide/
Heavy-Duty Oil-Tight indicators, buttons and switches
http://www.hubbell-icd.com/icd/pushbutton/files/2040Catalog.pdf
http://www.ab.com/en/epub/catalogs/12768/229240/229244/2531081/229759/tab3.html
http://www.cooperbline.com/product/electricalenclosures/NewProducts/SSPushbutton.asp
PLC
http://en.wikipedia.com/wiki/Programmable_logic_controller
http://www.ab.com/programmablecontrol/
PLC Common-Input, common-output, isolated-input, common-input, relay-output Cards
http://www.automationdirect.com/adc/Shopping/Catalog/Programmable_Controllers/Productivity3000_%28Programmable_Automation_Controller%29/AC_I-z-O_%28Relay_Outputs%29
OIT
http://www.automationdirect.com/adc/Shopping/Catalog/Operator_Interfaces/C-more_Micro-Graphic_Panels/C-more_Micro-Graphic_Panels_-a-_Keypad_Bezels_%28all_types%29/EA1-T6CL
http://nematron.com/
HMI
http://global.wonderware.com/EN/Pages/WonderwareHMISCADA.aspx
http://www.ge-ip.com/products/3311
http://www.atvise.com/?gclid=COGJ-4eKjJ8CFRAeDQod7mI1NQ
Relay Ladder Logic
http://en.wikipedia.com/wiki/Ladder_logic
http://ecmweb.com/ops/electric_basics_ladder_logic/
http://download.cadinfo.net/CAD-Manager/General/Symbols/Electrical-ANSI-Y322-Symbols.html
Quiz
Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.
DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.
