Why and when should you use a drive bypass?

How to reset a tripped ACS550

How to operate a Danfoss FC102 VFD using the keypad

What are Net Zero Energy Buildings (NZEBs) and why do they matter? NZEB guru Tim Wentz shares his ideas at a meeting of building technology experts. Meeting sponsored by ITT (Now Xylem) RCW.

Tim Wentz is a registered professional engineer, a LEED Accredited Professional and a member of the faculty of the University of Nebraska-Lincoln’s Construction Management program. He received MCAA’s 2009 Distinguished Service Award and is an ASHRAE fellow.

This from a new release from Pike Research:

"Because commercial buildings consume roughly 23% of all electricity globally, the automation systems that ensure efficient performance are a critical part of energy management.  Until the mid-1990s, modern building automation consisted of little more than individual systems with simple control panels for switches, timers, and alarms.  Today, the market for commercial building automation systems is in the midst of revolutionary change in terms of technology and utility.  In the last several years, the focus has shifted from an individual system view to a more holistic view so that the “building system” can be defined to include virtually any device or data source within the building.  The amount of data created by automation systems can be overwhelming, but real competitive and economic value exists in using the data to monitor performance and uncover trends.  According to a new report from Pike Research, the market for commercial building automation systems will double over the next decade, increasing from $72.5 billion in 2011 to $146.4 billion by 2021."

The complete release is here: http://www.pikeresearch.com/newsroom/global-revenues-for-commercial-building-automation-systems-will-reach-146-billion-by-2021

Timing the announcement with the AHR show this week in Chicago, Danfoss has introduced the VLT® HVAC Basic Drive - a small, full-featured variable speed drive that promises reliable, low-cost HVAC performance for basic fan and pump operations.

“In some fan and pump operations advanced drive features are unnecessary and, because they are superfluous, simply add to overall costs.  The VLT HVAC Basic Drive is an ideal solution that strikes the optimum balance between price and variable speed drive performance in these straightforward HVAC installations,” says Ed Smith, a company representative.

VLT HVAC Basic Drives minimize wear on HVAC equipment and maximize system up-time, while reducing HVAC system operating costs up to 15%. 

The company says that the VLT HVAC Basic Drive is the most compact drive in its class and with its specifications to reduce panel space requirements. Numerous built-in features reduce, and in some applications may even eliminate, the need for additional external equipment such as gateways, PI controllers and PLCs.  An Automatic Energy Optimizer function reduces energy consumption by up to 15%, while “sleep mode” functionality can help further reduce operating costs and extend drive life.  Bypass frequencies minimize operating noise, vibration and resonance issues.

VLT HVAC Basic Drives also feature a “start up wizard” that makes drive set-up fast and simple, and easy tool access further aids fast and effective commissioning and operation.  A robust single-piece enclosure provides reliable, maintenance-free operation in ambient temperatures up to 50 degrees C, with no external cooling required.  A unique cooling concept provides problem-free performance, even in harsh environments, without forced air flowing over the electronics.

Buildings are increasingly becoming air tight which causes a reduction in the air quality. Higher levels of carbon dioxide (CO2) can cause drowsiness and create an inefficient working environment. Most traditional ventilation systems ventilate for the maximum capacity of the room whether occupied or not. By using gas sensors to determine the number of people in the room, the ventilation system can ventilate appropriately and efficiently.

William Rhodes, Market Analyst at IMS Research commented, “Demand-controlled ventilation (DCV) is not a new phenomenon but has certainly seen a substantial increase in usage over the past 18 months. As governments and businesses look to generate energy savings, it is likely that DCV will continue to gain traction in the coming years and become the de facto standard for ventilation systems.”

The most common building automation sensor used for DCV is CO2. IMS Research estimated over 850,000 CO2 sensors were used in building automation systems across EMEA and the Americas in 2010. However, some vendors have started to advocate the use of volatile organic compound (VOC) sensors as an alternative to CO2 as an efficient method of DCV.

Rhodes continues, “There are definite advantages of using VOC sensors for DCV. VOC sensors can pick up odors and smells that CO2 would have otherwise missed. However, following extensive research, the general industry consensus is that VOC is an expensive solution and that it is not as effective as CO2 for DCV. VOC sensors are likely to be increasingly used for DCV, but mainly installed in kitchens and within or around toilets where they can detect organic compounds, including odors and smells.”

In my last post, I took a look at the results of some research I did regarding variable speed drive efficiency and motor efficiency.  In this post, I’ll take a look at why designers, in particular, building system designers, are driven to apply variable speed technology in their systems.  This, combined with the previous post, will lay the foundation for the next post, where I will look at what happens when you apply a VFD to motor serving a centrifugal machine in an HVAC system.  Its mostly good news, but there are a few surprises.

Variable Speed and Building System Loads
For folks like me in the building industry, VSDs in general and VFDs in particular are just about always applied to a centrifugal machine like a fan or a pump or a centrifugal chiller.  To some extent, the ability to vary the speed of a centrifugal machine as the demand on it changes is “God’s gift” to the industry because for HVAC and other building systems, just about everything varies all of the time.  Here is an example.

What you are looking at is the daily and seasonal load profile for a facility in Southern California that we developed using the building trend data.

We were going to add chiller capacity and instead of doing a model, we let the building tell us what the best chiller size would be and what “sweet spot” we should target on its performance curve by picking hourly flow and temperature data (which we knew was reliable) and doing the math.