Craig

Fieldhouse Geothermal Heat Pumps

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.

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.

Rare Earth Metals

Energy, Lighting, Magazines

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.

Saltwater Geothermal

HVAC, Magazines

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.

Itchy Shins

Energy, HVAC, Magazines

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.

Troubleshooting At The Museum

Energy, HVAC, Magazines

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.

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

US Lighting Market

Lighting

Jan 272012

I ran across the Department of Energy report on Lighting. It just came out and it is a survey or a census of Lighting in 2010. The report is called 2010 U.S. Lighting Market Characterization and it can be found on the DoE’s Solid State Lighting Technical Reports page. It’s a long report but it is full of charts and graphs. It gives you a good looking at what is lighting this country. There are still a lot of inefficient lamps in the field- mostly incandescent lamps in residential homes. Business and Industry has done a good job of upgrading their lighting.
Continue reading »

Bonus Rebates For T12 Retrofits

Energy, Lighting, Rebates

Jan 262012

Minnesota Xcel Electric customers- now is the time!

Those of you who still have T12 lamps in your offices and warehouse be aware that Xcel Energy is offering bonus rebates on top of their already generous rebates to change these older fluorescent lamps to newer T8 lamps with Electronic ballast. (T12 refers to the diameter of the tube in 1/8″ increments. A T12 is 1-1/2″ in diameter, whereas a T8 is 1 inch in diameter. But the real cost and energy savings come from the efficient electric ballast that drive T8 lamps. )

2009 U.S. Department of Energy (DOE) regulations require T12 fluorescent lighting be phased out in 2012 and will no longer be available. To help it’s Xcel MN customers with this change, Xcel is offering bonus rebates through 2012 for T12 to T8 retrofits, T12 to T8 optimization projects and T12 to T5 lighting systems.

Now through March 31, 2012, all Xcel Energy is offering 50% bonus rebates to their Minnesota business electricity customers. These T12 conversion projects must be completed and invoiced on or before March 31, 2012. T12 upgrades completed and invoiced between April 1 and December 31, 2012, will be eligible for up to a 30% bonus rebate.

Note: Rebates for T12 upgrades will not be available after December 31, 2012.
After 2012 there will be no more T12 fixtures sold and as of last year there are no more magnetic ballasts sold. T8s and electric ballast are proven technologies, so there is no reason to keep playing your utility company for more electricity than you need.

Rebates range from…

$18.00 – $28.00 per fixture standard program
$27.00 – $42.00 per fixture with the 50% bonus (ends March 31st)
$23.40 – $36.40 per fixture with the 30% bonus (ends December 31st)

Note: All rebate amounts are per retrofitted fixture. Rebates cannot exceed 75% of project cost. Applications must be turned in within 12 months of invoice date or no later than May 1, 2013.

Details can be found on the Xcel website although it takes some hunting to find the rebate forms.

Ghoulish LEDs

Lighting, Magazines

Jan 102012

In the current issue of Electrical Wholesaling, Jim Lucy, the chief Editor, comments on a side-by-side comparison of Fluorescent and LEDs he saw at Lowes. I’m not surprised. LEDs often have an odd color cast. LEDs are now as efficient as Fluorescents but they are still more money. LEDs do have their uses. Often they are ideal in low wattage situations like decorative lighting. I’m sure they will get better and cheap as time goes on.

But what really galled me is that the LED on display was emitting a ghoulish blue-white light that could only appeal to someone trying to duplicate the lighting in a 1950s-era Soviet interrogation room. By any measure, this display did much more harm than good to the admirable cause of LED lighting, particularly in a setting where homeowners and other potential retail customers are probably getting their first look at LEDs.

Predictive Control and TMY Modeling

Design, Energy, HVAC, Magazines

Nov 222011

Recently I fielded a call from an equipment engineer in Minneapolis regarding a HVAC modeling project. He asked about my experience working with ‘Typical Meteorological Year” (TMY) data sets. I’ve modeled a number of Heating, Cooling and Ventilation jobs were I needed the fine detail that TMY data sets provide. I told him the problem I had was using a spreadsheet. I found 8760 lines made for some unwieldy spreadsheets. Instead I put the TMY data in a database and worked my models using a hybrid of database calculations and spreadsheet calculations. He asked where to get the data. It can be found from a number of different sources online. I have been using TMY2 and now TMY3 data sets* from the National Renewable Energy Laboratory (NREL), other sources include…

TRY – ASHRAE’s Test Reference Year
WYEC – Weather Year for Energy Calculations
IWEC – International Weather for Energy Calculations
NCDC – National Climatic Data Center
TMY – Typical Meteorological Year

According to D.B. Crawley’s paper, “Which weather data should you use for energy simulations of commercial buildings?“, either WYEC nor TMY will work fine. These data sets are pretty good, however you need to keep in mind- they fail at the temperature extremes. The data sets are designed to weed out extreme tempertures in order to create smoother data sets. This can be problematic if you’re also using the simulation to size your equipment. Having said that, these TMY based models will be far more accurately modelling energy usage than using bin hours. They are also better when running what-if scenarios. In order to truly model a building for energy use, particularly where humidity control comes into play it is essential to model the energy use for each hour in a typical year- all 8760 data points.

Detailed hour-by-hour modeling using hourly weather data sets has become commonplace in the evaluation of design alternatives and the design of HVAC systems for larger buildings. For residential and small commercial buildings, calculating design loads based on high and low design temperature is still common practice. The economic issue is when the added cost of the more involved hour-by-hour modeling exercise can be expected to be justified by helping to guide the selection of equipment that provides significantly better part-load performance, resulting in tangible benefits of lower total annual energy cost and better comfort control in the building.-December 2010 ASHRAE Journal.

Other uses of TMY data sets are to adjust set-points based on outdoor temperature to control early morning pre-cooling. Both to take advantage of Lower temperatures and reduced peak demand rates. Building mass can also be used for energy storage. Off-peak heating and night cooling can be based on TMY modeling; shifting HVAC demands to off-peak hours and lower energy rates.

Some of this predictive control is finding its way down to the residential market with smart thermostats. I predict we’ll be seeing more of these smart thermostats… “A trial in 2000 households by Oncor Utilities in Texas resulted in heating and air-conditioning power cuts of 20% to 30% and annual savings up to $400. It also achieved complete AC turnoff at peak hours due to pre-cooling. These examples indicate that approximately 10% of energy to condition buildings can be potentially be saved by the use of control algorithms using forecaster weather conditions.”

*Note: The TMY3s are data sets of hourly values of solar radiation and meteorological elements for a 1-year period. Their intended use is for computer simulations of solar energy conversion systems and building systems to facilitate performance comparisons of different system types, configurations, and locations in the United States and its territories. Because they represent typical rather than extreme conditions, they are not suited for designing systems to meet the worst-case conditions occurring at a location. -NREL

Cool Summer Energy Savings

HVAC, Lighting

May 172011

Missouri River Energy Services (Moorhead Public Services) has five helpful hints to cut your energy costs in the summer months. I have a couple comments…

#3. Adjust cooling equipment to occupancy schedules.
In the upper midwest this provides larger energy percentage savings due to the narrow spread between the summer design temperature and the indoor temperature.
Unlike the winter where the spread would be 5% in the summer the spread is closer to 25%.*
In the evening this spread narrows more until your cooling equipment doesn’t run at all.
Note: If you are on a Time-of-Day rate, be sure to program your equipment to come back on early enough to take advantage of the lower energy rates.

#4. Upgrade lighting systems.
“Efficient lighting technologies also give off less heat, which reduces the need for air-conditioning.”
This savings is rarely calculated, but it is real and substantial. For commercial buildings. even in our cool climate, we often find cooling equipment running six months or more during the year. By cutting the internal load of your building, not only does your equipment run less, but you can also resize the equipment when it is time to replace it, creating even more savings in upfront equipment costs and maintenance.

* Calculations
(5 degree setback / (70 degree indoor temperature – (-30 Degrees) winter design temperature)) = 5/100 = 5%
(5 degree setback / (90 degree Summer design temperature – 70 degree indoor temperature)) = 5/20 = 25%

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