Oct 282014
 

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.

Northrop Auditorium

Northrop, previously known as Cyrus Northrop Memorial Auditorium, is a stage venue at the University of Minnesota in Minneapolis, Minnesota. -Wikipedia

 Posted by at 12:00 pm
Jul 242014
 

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.

May 152014
 

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.

Apr 302014
 

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.

Apr 242014
 

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
Incandescent 12.2 10.7 11.5 06.3 0.0194
100W metal halide 09.1 03.2 06.5 48.1 0.1398
T12 magnetic 09.6 04.6 07.2 35.1 0.0897
T5HO electronic 10.5 10.0 10.2 02.7 0.0036
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.”

Apr 112014
 

Thirty years ago I started selling Geothermal Heat Pumps, when I worked at Baker Wholesale in Fargo. We had one customer who was a well driller and he expanded his business into Geothermal. My father helped him design bigger and bigger systems. The bigger the facility the better Geothermal looks. In addition to the greater efficiency, there is also greater flexibility in a multi-zone facility.

In the April 2014 issue of Energy Systems Magazine, Daniel Cohen writes about the Ping Tom Memorial Park Fieldhouse. The field house runs its geothermal heat pumps off of 16) 650-ft-deep vertical wells. This is five times deeper than the well fields we would normally design, but I’m sure they had land use issues so going deep was easier than the drilling more wells.

Ping Tom Memorial Fieldhouse

Chicago’s Ping Tom Memorial Fieldhouse
photo by James Steinkamp/Steinkamp Photography

Environmental Systems Design (ESD) selected Geothermal units for their high energy efficiency ratio (EER) and coefficient of performance (COP). They are estimating a COP of 4 making this heating system 400% more efficient than straight resistant electric heat. In addition they connected modular heat pumps in each zone throughout the field house.

“The heat pumps are independently controlled which allows for energy to be shared and distributed from zone to zone.”

Downsides to Geothermal: it is slightly more expensive to install, but the long term energy profile and operation cost savings makes it the perfect energy source for buildings large and small. Geothermal systems need land to drill the well field, but once it’s in you can use the land for anything you want.

I also like how ESD used CO2 sensors to modulate ventilation airflow based on occupancy. By using VAVs and controlling the ventilation load, the building can retain much of the heat that other buildings vent outside. Add in the Economizer and Energy Recovery system, this building should be inexpensive to operate.

Mar 252014
 

I’ve been interested in Rare Earth metals since the run up on prices in 2010. Not because it was an investment opportunity but because it dramatically affected Fluorescent lamps prices, which had been stable or falling for the last decade. The subject is also interesting because it deals with global politics, which I’m interested in, and Chemistry, which I studied in college. Recently the BBC ran an article on this topic in their magazine.

In addition to Fluorescent lamps, Rare Earth metals are used in LEDs, Wind Turbines, and all matter of green energy. What is ironic: mining Rare Earth metals is one of the least green activities on this planet. And thanks to laissez faire government policies in China, almost all mining of Rare Earth metals was done in China. It wasn’t that China had the only supply. No, in fact Rare Earths are not rare, and can be found all over the world. China didn’t sweat the environmental degradation, whereas Western countries did. But that changed in 2010 when China got tired of fielding environmental complaints of their citizens and foreigners alike. Economically, it also made sense to keep the metals in country- letting their own manufactures buy at a subsidized price, while forcing foreign companies to bid on the metals limited by their export quotas. This drove the prices way up. There are no substitutes for these exotic metals, and no secondary sources. Speculators drove the market as well. This cause prices increases everywhere, which caused complaints to our government.

Just how dependent the entire world is on Chinese rare earths became very clear at the end of 2010 when China threatened to restrict supplies. The spike in rare-earth prices was very dramatic – up to 3,000% for some of them. Prices have since fallen back, but the shock was enough to prompt companies to begin to explore producing and refining rare earths elsewhere in the world.

Source and graph: BBC, and Bloomberg.

Continue reading »

Mar 052014
 
Spring Point Ledge Light is a sparkplug lighthouse in South Portland, Maine that marks a dangerous obstruction on the west side of the main shipping channel into Portland Harbor. It is now adjacent to the campus of Southern Maine Community College.  The lighthouse was constructed in 1897 by the government after seven steamship companies stated that many of their vessels ran aground on Spring Point Ledge.

Spring Point Ledge Light is a sparkplug lighthouse constructed in 1897, adjacent to the campus of Southern Maine Community College.
photo by Paul VanDerWerf (Flickr)

I’m not sure it’s possible to be further from seawater than in Fargo, North Dakota. That said I found this article by Rob Klinedinst and David Reinheimer, using a Geothermal heat pump with seawater, fascinating. The authors explain why the Southern Maine Community College (SMCC) in South Portland, Maine decided to go with geothermal, and the issues using seawater rather than a closed loop with a glycol solution. I was reminded of my early HVAC years: the first geothermal jobs we work on at Baker Wholesale were open loop systems. We were using Friedrich heat pumps on some large residences, where they had access to active aquifers. This was somewhat rare, so it didn’t take long until we were only designing close loop systems using Command Aire and Econar heat pumps.

The issues using sea water are corrosion and the temperature range of Casco Bay:

Initial roadblocks to using seawater were to find equipment that could efficiently handle the wide temperature ranges in Casco Bay and the corrosiveness of salt water. Only one heat pump model was found with a heating water temperature range of 14°F to 113 ° F, and this was coupled with a system used in the maritime industry — a cupronickel underwater ‘ship-keel cooler’ heat exchanger — that is highly resistant to saltwater corrosion. On ships, the heat exchanger is used to reject heat, but here, it is used to both extract and reject heat from/to the sea.

Rob and David (Harriman’s Higher Education Design Studio) searched the world looking for solutions that would let them take advantage of the sea. They found seawater pumps in Japan, filters and strainers across the country in California, titanium plate-and-frame heat exchanger, and insulated piping systems. All while working with the EPA to get approval. I would have given up before working with the EPA- that could not have been a good experience. The SMCC had a deadline to renovate the Lighthouse Building. The EPA was talking about studies and field testing. HHEDS decide to use a heat exchanger and keep the sea water in the bay.

The cupronickel heat exchangers are located under a nearby dock and positioned three feet below low tide. An uninsulated pipe loops between the heat exchanger and the building. Running the pipes under the ground (an added geothermal source) eliminated the cost of insulated piping. The pipe is filled with 50% food-grade propylene/glycol, with inline pumps moving the liquid at 75 gpm.

Feb 032014
 

Not only is Fargo cold for six months of the year but once inside the air is dry. I can feel my skin dry up and start to itch. We make sure our humidifiers are working. They’re almost as important as our furnace. But my shins aren’t the only reason to humidify the air. Machines work better, wood doesn’t shrink or crack, and optimal humidity will even keep the doctor away. Gary L. Berlin in the February issue of Engineered Systems, writes on the topic in his article, “Restoring The Low Limit For Indoor Relative Humidity.”

Berlin describes the research history into humidity and health. He covers the what the industry has done to through its ASHRAE established standards to keep humidity at recommended level. And how more work needs to be done to keep indoor relative humidity from falling too low.

See this Sterling Humidity Chart. A decrease in bar width indicates decrease in effect.
Source: ASHRAE, adapted from Sterling et al., 1985.  Lennox.com

Sterling Chart (Optimum relative humidity range to minimize harmful contaminants)

In the early 1980s, Elia Sterling of the University of Vancouver did an extensive study of previously published research concerning indoor relative humidity and its effect on the occupants of an indoor space. This study established that both high and low relative humidity levels had a deleterious and costly effect on the health and productivity of the occupants of a facility as related to bacteria, viruses, fungi, dust mites, respiratory infections, allergies, asthma, and ozone in the workplace, schools, and home.

Continue reading »

Jan 052014
 

In the new issue of Engineered Systems, Doug Lucht, writes up his experiences troubleshooting an Air Handling Unit at an art museum. He describes the steps he took to locate the problems in an air handling system that never worked properly. The facility had to turn on the chillers as early as March with sub 45-degree temperatures, when the economizers should have been taking care of the building. I love a good mystery and it points out- facilities should not just except poor performance of their equipment but should get to the bottom of it. Solutions were found, Lucht writes…

Once the booster fan was installed, AHU-9 could fully economize. The museum could now keep their chillers off further into the spring and shut them down earlier each fall. They were also able to completely abandon the roof-mounted chiller that served the chilled water fan coil units. Shortly after implementing the solutions, the museum received a check from their utility provider, which made the facility manager look like a hero to the museum curators.

This story also illustrates why cobbling together new and old equipment isn’t always the best way to save money. It demonstrates there are small upgrades that can make big changes to the facility’s comfort and bottom line.

VBA-18 to 190 Ventasen Booster Fan

Ventasen Booster Fan
Product# VBA-18 to 190.
Airflow:144-1900CMH