Every full Energy Audit should look at Power Factor. It’s funny how often it comes up. Even when you don’t think you have a problem you might in the future.
I first heard about Power Factor Corrections in the late 1980s. My friend’s dad worked for Border States Electric (BSE) as an engineer. He came over to the BSE from Northern States Power (Now Xcel Energy). He was one of the first guys in the area to work on solving this problem using banks of capacitors. He would tell me how electric motors would create a lagging power factor. His job was to calculate the capacitance necessary to correct for low power factors. It didn’t hurt that BSE got a lot of orders for switched capacitor banks.
In the 1990s, my dad and I started to do some energy audits of our own. We would run deal with facilities looking to increase the efficiency of their equipment. It was there they would run afoul of low power factors. Utilities don’t like low power factors and will bill a penalty if your power factor falls below a certain threshold. Our lighting retrofits would have very clean power and high power factors, but because we were using substantially less energy for lighting than before- there was less clean electricity to dilute the dirty (low power factor) electricity, which the motors were using, and hence the facilities would be getting billed a Power Factor penalty. The solution: capacitors and/or new energy efficient motors- but that’s a story for another day.
If you’d like to learn more about Power Factor corrections and motors, I have this article from Moorhead Public Service and their partners at Missouri River Energy Services.
Back in 2010 when the China’s started phasing in their export controls on Rare Earth metals, I suggested to my Sylvania rep, that the shortage would be short lived. “The Chinese are corrupt, once the price starts rising, they will find ways to get extra production into the market.”
I see in a recent Bloomberg.com article “Rare Earth Stocks Rise After China Approves MinMetal’s Group” that was the case.
China, supplier of more than 90 percent of the world’s rare earths, aims to create fewer and bigger industry groups to help technology upgrade and crack down on illegal production.
I’m guessing it’s too little and too late. China is still corrupt and other supply sources are coming online. In the meantime I have seen prices on Fluorescent lamps start to drop a tiny bit. Every fluorescent lamps uses rare earth metals. It’s the ‘phosphors‘, which makes each lamp burn at the correct color temperature. The more efficient the lamp, the more rare earth metals the lamp uses. Hopefully, world supply of these wonder elements won’t be limited, and the price will continue to come down to earth. See my earlier article: Rare Earth Metals.
It’s hard enough to update the HVAC systems on a older building, but if it is the historical Northrop Auditorium (1929) it is doubly hard. Edward Clements writes about the issues the University of Minnesota faced updating the mechanical and lighting systems this building. In the current issue of Engineered Systems.
“Chilled beam terminal units were also used to provide a thermally comfortable environment while minimizing total system airflow in the back of the house, and a dual-wheel energy recovery AHU (Air Handling Unit) was used to deliver air to the space.”
In addition Clements writes about Displacement Ventilation, Atrium Smoke Control, and Lighting updates. There was a lot work require to reopen by April of 2014.
One small issue with LEDs is they have a different quality of light. We have measurements that worked well with Incandescent, HIDs, and Fluorescent lamps. CRI (Color Rendering Index) which gave us a relative measure of quality and CCT which gave us a lamp’s color temperature. But these measurements were based on factors that are no longer in play in the world of solid state lighting.
In the July-August 2014 issue of Architectural Lighting, Alice Liao writes about the issues facing the consumer of quality lighting and the issues facing the professional user of lighting.
“Both CRI and CCT are derived through rote mathematic simulation rather than through empirical measurement. CRI testing is calculated on a computing device using a source’s spectral power distribution (SPD), a diagram that depicts the radiant energy a source emits at different wavelengths of visible light—wavelengths of 380 to 780 nanometers—and the spectral reflectance of each color chip. CCT is also computed from the source’s SPD.”
After Lias discusses the short comings of these measurements, we’re introduced to the Color Quality Scale (CQS). Developed by the National Institute of Standards and Technology. The CQS tests with a broader range of colors, higher chromas and deeper saturation.
“CQS also factors in extreme color temperature, which impairs a source’s ability to render color, and takes a root-mean-square of the color shifts of all 15 test colors rather than an average. This ensures that poor performance on a few samples is given proper weight.”
I am hopeful the IES Color Metrics Task Group will come up with a simple scale for consumers who are already confused about LEDs. They should also develop a set of ratings for Professionals, whose requirements for light require more data not less. For those interested in this important topic, I highly recommend this article.
Xcel Energy has announce more LED fixtures available for rebate.
- Parking Garage
- Outdoor Area Lighting
- Street Lighting
Xcel requires Invoices dated on or after August 12, 2014. Equipment must be DesignLights Consortium qualified.
I assume the rebates are available in all of Xcel Energy’s service areas except ND.
The following LED Info Sheet and rebate applications are available.
- LED Info Sheet featuring our full line of LED rebates
- Lighting Efficiency Retrofit Rebate Application
- Lighting Efficiency New Construction Rebate Application
More information on Xcel Energy’s Rebate programs.
A follow up to Indoor Farming from May. LedsMagazine.com has published a new article that reviews the basics:
“The narrow spectrum of LEDs in different colors can be selected to enhance the photosynthesis process while also offering energy savings relative to broad-spectrum HID or fluorescent lights used in commercial farming.”
There is practical knowledge from a number of test farms in the U.S., Japan, and Europe. There is also research taking place at two Universities. Purdue University is looking at LED light with bedding plants. And McGill University (Quebec) is studying tomato production under a mixture of different light sources.
It’s cold for most of the year in North Dakota, so I’ve gotten familiar with growing seedlings under grow lights before Memorial Day. I didn’t realize you could keep on letting them grow. Green Sense Farms in Portage, Indiana, have used the unique properties of the LED to grow Herbs and Lettuce indoors. LED lighting can tuned to the very frequencies of light that plants love. The efficiency of Solid State lighting allows stacks of plants to be grown in warehouses. The advantages are climate control, nutrient control, water control, pest control, and 20–25 harvests per year depending on the crop.
I’ve did some research on the topic when I was building my own T8 Fluorescent fixtures. I used 6500K lamps and the seedlings grew fast and the fixtures used 40% less energy than with T12 grow lamps. I would love to test some of Sylvania’s LED ribbon strips in these more exotic color temperatures. (almost purple light) In the meantime, check out this article at LEDsMagazine.com for more information on the Green Sense Farms or this article on Broccolicity.com.
I have no experience with data centers and ‘Mission Critical’ HVAC systems, but the topic combines three things I’m interested in: Computers, HVAC, and Systems. When I was just a kid I spent a week at Control Data Corp. in Minneapolis. During one of the hottest weeks of the year, my mentor taught me programing. There was no air conditioning at home but in the equipment rooms it was 68 degrees. You almost had to wear a sweater.
Jump forward forty years, and the equipment rooms are jam packed with servers. The cooling load is larger than the equipment load, and they’re cooling 365 days a year, even when it’s -20 degrees outside. Some brave souls are starting to think twice about how they cool their servers. Companies like Google and Facebook have so much invested in their server farms, that any savings translate into millions of dollars.
Kevin Dickens, P.E. in the April 2014 Engineered Systems looks at opencompute.org and their Open Compute Data Center Mechanical Specifications. Open Compute Project is an open source consortium of data centers and equipment manufacturers and interested partners including Facebook. Dickens muses on were all this experimenting has taken us and where it might lead.
For most of us, change has to be incremental. Our risk model does not allow us to step too far outside of our, our management’s, or our client’s comfort zones. But when we can learn from those on the bleeding edge, we should have the courage to step out onto the leading edge. We do that not by stepping out of our comfort zone but by educating ourselves and expanding it instead.
Who doesn’t love a good Psychrometric Chart.
As we enter into a new generation of lighting: Solid State; commonly known as LEDs, we need to be aware of the issues that drive the technology and hence the cost. LEDs Magazine has an article on LED Driver Design in their April/May 2014 issue. One of the issues that everyone hates is flicker. In Fluorescent lamps, this was caused by poor ballast design or bad sockets. With LEDs, the driver operates off of line voltage with its 60hz cycle, which can cause a 120 hz flicker.
Flicker Index by Light Source*
|Source||Max.||Min.||Avg.||Flicker (%)||Flicker Index|
|100W metal halide||09.1||03.2||06.5||48.1||0.1398|
|LED on DC||43.4||41.0||42.2||02.8||0.0037|
|LED with flicker||16.0||0.06||06.3||99.3||0.4498|
*Percent flicker is a relative measure of the cyclic variation in output of a light source (modulation index). The percent flicker is based on the maximum (A) and minimum (B) light output levels. You divide the sum of A and B by the difference of the two to obtain a percentage.
There are a couple possible solutions, and this article by Zhaoqi Mao, Lane Ge, and Gary Hua of Inventronics (Hangzhou) Co. describe them in detail.
- Passive or valley-fill Power Factor Correction (PFC) stage plus a DC/DC-converter stage.
- Single-stage Active PFC driver architecture
- Active PFC stage plus a DC/DC-converter stage
- Active PFC driver architecture plus a Ripple Suppressor
The take away is you get what you pay for, the buyer of LED lamps whether at the retail or wholesale level should be aware there trade offs in Driver Design. Just buying or stocking the cheapest LED lamp or systems is a good way to be disappointed.
“As the LED lighting industry develops, features like high efficiency and long life alone cannot satisfy the market. People are looking for a better lighting environment, especially when it is related to health. For certain places like offices and living rooms, elimination of strobe flicker is even more important.
There are multiple ways to create good DC current with low ripple to drive LEDs; each method has advantages and drawbacks. The key advantage of the ripple suppressor is that it provides a very simple and flexible way to reduce the flicker of the design we already have at a minimal and very reasonable cost.”