first unitarian society of minneapolis saves over $16,000 a year with energy-saving measures
DESCRIPTION
In May 2011, EPA launched the ENERGY STAR National Building Competition: Battle of the Buildings. In its second year, the Biggest Loser-style competition featured teams from 245 buildings across the country in a head-to-head battle to save energy and reduce greenhouse gas emissions. And guess who won in the House of Worship category? The First Unitarian Society of Minneapolis!This presentation is an overview of their energy-saving measures. You can also read an interview with Bruce Nelson, a member of the congregation, about how they saved all that energy here: http://bit.ly/s3d09X.TRANSCRIPT
August 18, 2011 EPA ENERGY STAR National Building Competition Event
First Unitarian Society900 Mount Curve Avenue
Minneapolis, Minnesota 55403
August 18, 2011 EPA ENERGY STAR National Building Competition Event
First Unitarian Society900 Mount Curve Avenue
Minneapolis, Minnesota 55403
Building and Grounds Committee for First Unitarian Society approved a performance based contract for classic recommissioning.
Projects included:People-PowerFind and Fix
New Must Be Better
August 18, 2011 EPA ENERGY STAR National Building Competition Event
First Unitarian Society900 Mount Curve Avenue
Minneapolis, Minnesota 55403
People-Power Partnering with our most important resource to manage energy consumption – People. This
includes:● Planners and schedulers of room use to allow use to match occupancy, ● Building staff and Users who can be the caring eyes, ears and hands to observe and
curb use (turning off hallway lights when adequate daylighting is present for example),
● Volunteers to help with building envelope issues, addition of timers on line loads, and reporting lighting, energy use, and climate issues.
August 18, 2011 EPA ENERGY STAR National Building Competition Event
First Unitarian Society900 Mount Curve Avenue
Minneapolis, Minnesota 55403
Find and Fix● 24/7 fan operation now managed by stats. ● Steam valves that never closed all the way were repaired, adjusted. ● Elements in steam traps that were leaking were replaced. ● Setback reactivated building wide, enhanced by schedule in large areas. ● Control air leaks found and remedied reducing run time and heating shutoff issues. ● Mixed Air adjustments were managed to occupancy.
August 18, 2011 EPA ENERGY STAR National Building Competition Event
First Unitarian Society900 Mount Curve Avenue
Minneapolis, Minnesota 55403
New Must Be BetterAfter the existing systems were made functional and optimized, and savings immediately earned (within
the first month), a new use benchmark was the target to beat through any refits, upgrades, modernizations. Many typical replacements and renewals had long term paybacks but adverse short term
cash flow effect. An investment in Control additions was made for:● one AHU that accounted for 20% of the building’s steam/heating use, enabling programmable
scheduling and enhanced setback (went from 24 heating cycles a day on an avg 20 degree day to 18 per day on the pneumatic stat – under same OA temps, the unit now cycles avg 12 times per WEEK to warm up Thursday evenings and Sundays).
● a ‘smart’ cutout control for both the boiler (45 degree boiler cutout in Fall-Spring with 68 degree interior override), and main AHU fans (71 degree fan cutout in Summer). 3 year cost recovery predicted, trending at 2 years presently.
● Nocturnal Free Cooling function was added to 2 main AHU areas: thus climate comfort periods in this heating only plant was increased, along with fan run time in the fall-summer-spring. The energy savings would have been greater without this extra fan run time, but climate comes first.
Your Tour Guide
● My name is Ken Duvio. ● Since 1988, my Facilities Management
background includes many requests by building principals to investigate and control energy costs locally, regionally, and nationally. I hold a bachelors degree from Tulane University, and certification in my profession.
● I work as a consultant/teacher/technician, thus you'll see me on site dressed as appropriate for the Boardroom, Workplace Tenants and Users, roofs, tunnels, ceilings, and equipment rooms.
● The following slides offer a look at recommissioning finds, fixes and additions that have reduced energy and fuel consumption at First Unitarian Society of Minneapolis.
● The comments are meant for a non technical audience, while providing info to your building technical and operating engineering staff.
● I hope this will help to identify and recreate similar energy cost management work at your buildings. www.nfs-llc.com
"You already have one of those.It's just not hooked up."
● When I first toured, the Building and Grounds committee was aware that the fans ran 24/7 from October to April.
● I was asked initially to see if FUS could purchase some sort of starters to allow the pneumatic stats to turn the fans off and on with the heating (steam) valves.
● I’m staring right at the pneumatic starter, original equipment, present on all main AHU’s, jumped out.
● Easy fix, reconnected the control air off the stat branch to the steam valve www.nfs-llc.com
Lower Auditorium (LA) was at 85 degrees in February of 2010, set at 68 degrees.
● First thing I responded to on site while intending to get the fan starters hooked back up. Custodian mentioned the Cafeteria-Dining-Stage area was over 80 degrees. I thought, ok, we all exaggerate a little… then I walked in and measured 85.
● Blown diaphragm on the actuator, venting control air (compressor running excessively, some valves throughout the building probably not closing all the way) and thus unit was running full heat 24/7.
● Rebuilt the actuator, reseated the valve. $23 part.
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Excess UA Heat CyclesCount the pink peaks (always on) and the purple peaks (with fan turning off and on)
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Motor Starters, Lower and Upper Auditorium Fans
● In Year 1, we reduced the motor run time by re-enabling the existing pneumatic motor starters.
● This was just the beginning. Datalogging recorders were showing wild readings from the heating coils, as if they never turned off.
● And the outside air intake was running about 50% open in deep winter – imagine those fans running 24/7, blowing a heat cycle in the room to warm it, then blowing 50% of 20 below zero outside air, heating cycle to bring it back up, and repeat… expensive.
● Parts costs – zero. Just reconnections, adjustments.
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Heat Won’t Turn Off – Steam Valve Leak● Stage 1 and 2 of the Upper
Assembly Fan, an Air Handling Unit (AHU) accounting for up to 20% of the building steam/heat consumption, would not close all the way.
● Stage 1 (rear) remedied by a new diaphragm ($23.00 part).
● Stage 2 (front) remedied by adjusting the valve stem length in the actuator.
● Year 2 Digital Control – Stage 1 valve is primary, 2 opens only as needed to recover – we then ramp back to 50% to complete a heating cycle.
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"By tracing and labeling air, electric, heating, return, and sensor lines and devices, you can map your existing system - this
creates answers, and questions."
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Outside Air/Return Air Adjustments● As mentioned, we had 50%
OA in the largest space in deep winter, 25% Downstairs in LA. There were problems with the control air to the dampers… they were not hooked up to ever purge when the AHU shut down (and when the fan runs all the time…)
● Some fittings, tubing, elbow grease, line tracing. Note labels in the lines, so techs in the future don’t have to untangle the birdsnest again
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Summer, Winter Adjustment● Found some return air
diluting our Free Cooling operation, thus reducing efficiency. Correction to control air pressure to the damper on the ‘cooling’ stage drove this full closed, OA full open. This saves fan run time.
● Same but reverse adjustment applies in the winter: enough makeup air during max estimated occupancy (about 15% works, and then the fan shuts off and the OA dampers close to preserve the heating that the unit just performed.
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Overheating the Entry Foyer
● Steam valve would not close
● Remade leaky control air connection, replaced diaphragm
● Still overheating● Off season, pulled the
valve assembly and discovered a bad valve seat. Replaced seat and valve stopper.
● $40.00 rebuild kit bought on Ebay
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Adjusted Thermostats● I found most pneumatic
stats off by 5-8 degrees, and recalibrated…
● Only to discover control air leaks to many of the radiator steam valve actuators due to dry rotted plastic tubing
● And radiator valve actuator heads that were shattering in my hands, only to learn they weren’t the type rated for steam valve heat! Since construction: wrong actuator heads.
● So once all that was fixed (head rebuild parts averaged $15-20 each) the stats were recalibrated again.
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Adjusted Thermostats● Most of these were just
buried on the highest setting.
● This Danfoss sensor was hooked up to a valve head that was cracked, but dutifully tied back down to it’s seat by stainless steel wire, which had over time stretched and uncoiled at the twist-tie down spots to let the valve stay wide open and consume steam.
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Heating Valve Not Closing, Fan Coil 2
● Smaller unit, harder to figure this one – the control air just wasn’t there. Chased the line down with a pressure gauge until I got right up to the valve. Leaking at the seam, rebuilt the head. $15.00 part
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Heating Valve Won't Open, Fan Coil 1 ● FC 1 had several urban
legends I heard, including reports that the steam lines were capped to this unit years ago. Well, sometimes it heated, sometimes not.
● The clip that holds the valve stem to the actuator head was undone. The stat was moving it, the steam line was active, it just wasn’t always pulling the valve open.
● Ok, you’re looking 14 ft straight up, and wedging yourself 12 inches between hot steam and condensate lines to work on an actuator that’s over your head and horizontal so all the guts go flying across the room and down when it was taken apart. Not fun, but fixable!
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Condensate Return Temps● Tracing back from these
thermometers when they’re showing in excess of 110 degrees (2 were in the 220 range) might not always be the easiest thing to do. Shoot the return line from the steam trap in each radiator, down the line a bit if you can, with the IR thermometer.
● One hard to find leak was actually the plastic head on a Danfoss valve that had split – another valve that never closed. Steam trap then needed replacement as well.
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Steam Traps● Once the leaky control
air lines are remedied;● And the steam valves
that won’t close all the way are fixed
● And the thermostats are calibrated
● It’s time to look at the steam traps to ensure they’re not bleeding steam back into the condensate lines
● An IR hand held thermometer can help identify these lines when hard to reach
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Good Filter Maintenance - Economizing● Paper is cheaper than
metal. So is oil. ● Note the outside air
dampers open during a summer day, 67 deg OA, thus we can cool the UA for a function in August without mechanical cooling. Nature cooperates a bit more reliably in Fall and Spring. Mid June through mid August, not much help.
● If/When mechanical cooling is implemented, this never goes away: this is Economizer mode, something that I find rarely works properly in many buildings, and results in excessive compressor run time when you could be ‘throwing the windows (dampers) open’
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RTU Evaporator and Condensor Coils● These were well maintained
by the contractor. ● I have seen MANY cooling
and condenser coils on Roof Top Units (RTU’s) clogged with lint and debris nationwide in my travels for a major retailer. Some coils are so clogged they resemble fur coats!
● I’ve seen just as many control system boards and sensors that were not hooked up correctly or at all.
● This unit is apart for a signal wire to the Dietrich Room programmable stat.
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Coil Cleaning
● The AHU and Fan Coil heating coils were clean, thus good filter maintenance.
● Here is a condenser coil for one of the kitchen refrigerator/freezers. Cleaning these with a soft brush/vacuum can help all year round.
● Caution: When you clean these, TURN THE STAT UP a little – it will cool more efficiently, so less power/run time is needed; OR, you might freeze and ruin food in the big refrigerators and walk in’s. Watch the temps!
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Someone’s in the Kitchen
● There was a piece of fiberglass insulation intermittently jamming the contactor in the On position – to the electric hot water heating booster pump for the dishwasher. Not something I expected to find. Just moved back the insulation after removing the excess (power to the unit off of course)
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Domestic Tap Water Heating● This unit short cycled a lot● Several issues – here’s a model
for all these investigations: what was the original problem? How many layers of “Fixes” have well meaning technicians added to just get the hot water working?
● The Side Arm heat coil had not been de-limed in ages, and the high temp-low flow safety was shutting the pilot and gas valve off.
● I found the safety jumped out● And the flow switch for the
recirculating motor defeated to ON
● And the stat would just run the HWH with only the hi limit switch to cycle things most of the time. But no one thought about the flow safety. Flushed a lot of slag out of the unit, reset the flow switch, reconnected the safety, then de-limed the Side Arm heater.
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Line Timers on Window Units
● Staff gets into the act! Addition of timers to the window unit power cords keeps the AC off at night when the school rooms are vacant just in case the faculty forgets to hit the switch.
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Programmable Thermostats● Basic 7 day, 4 period per day
programmable stats were added to
● LA (also enabling Free Cooling fall-spring-summer damper control)
● Dietrich Room (RTU for cooling, small steam valve FC for heating, now the two can’t run at the same time!)
● Offices (cooling only, but programmed to recover before the work day starts and shut down after)
● Part of the capital work. Refitting a unit to one of these runs anywhere from $300 to $700
● SETBACK now programmed in for extended hours, further back than the pneumatic stats would allow.
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Year 2 Capital Improvements:Cutout Control, Boiler and Fans
● Having established that with simple repairs and adjustments, use reduction and cost savings are predictable, AND we start putting some of that cost savings in the bank,
● THEN we look at ‘improvements’ – but look out, the new performance baseline is in effect. We have to improve on what we’ve just established, and the improvements have to pay for themselves else they’re just a fancy luxury.
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Cutout Control, Boiler and Fans:Trending, Alerts, Internet Access
● Alerts set up for Flame Failure, Low Water, Low Temp, Control Air Out of Range.
● Can trend outside air temperature, control air to ensure building wide pneumatic setback is functioning, idle-purge-fuel status, inside temp
● Has an inside temp override to enable the boiler and control air system should the inside temp go below 66 degrees – sometimes the 45 degree cutout might lead to inside cooling during long periods at or above 45, with no sunlight.
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Year 2 Capital Improvements:Cutout Control, Boiler and Fans
● On top of that conduit is an outdoor air sensor. This is pivotal to the new system.
● We have determined that when it’s 45 degrees or warmer, the boiler can shut down. We have a control loop to the UA, LA and FC fans that also disable the fan starters when the AHU’s can’t heat.
● In the Fall and Winter, we play with settings ranging from 55 to 72 – when it’s too hot outside to cool the rooms, the fans shut down no matter what the stats are trying to make them do.
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Internet Programmable Controller for Upper Assembly Fan:
Cutout, setback, scheduling, 2 stage heat, overnight cooling.
● Using Mamac Maverick Stats (designed, and built in Chanhassen).
● Hybrid system – these control inexpensive skinner valves to slowly dump control air to the steam valve, opening it after the fan starts, in response to programmed time and temperature.
● On line via port forwarding in the router, password protected
● Out of range alerts programmed to cell phone, email, etc.
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"A fan in the open window on a cool fall, summer, or spring night"
● It was cheaper to have the new digital controller run the outside air and return dampers on control air rather than purchase motorized damper motors; thus, to keep the main building compressor off in the summer, this $60 unit comes on as “stage 1 cooling” to drive the return dampers shut and outside air dampers open at night or whenever the outside air is cool enough to cool inside the building.
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More on the UA Intervention● We went from 24 cycles
a day to 18 on a unit that accounts for more than 20% of the buildings steam consumption.
● Now, with a 50 degree setback, and the unit only warming up 2 nights each week and for Sunday occupancy,
● We have recorded less than 12 cycles FOR AN ENTIRE WEEK for this AHU under the same OA temp conditions!!!
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Live Time View of First Unitarian SocietyUpper Auditorium and Boiler Controls
● These are read only, and password protected, so you can’t do anything to change or effect the settings to the units. It’s safe to look.
● These should open in a separate web browser window on your PC, Laptop or PDA:
● Boiler Control● Upper Auditorium
AHU Control
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Electricity Consumption Reduction
www.nfs-llc.com Prepared by Bruce Nelson, PE
Energy Star Portfolio Manager Tracking
www.nfs-llc.com Prepared by Bruce Nelson, PE
Utility Audit RecommendationsThe find and fix work that earned immediate, cumulative and
durable savings was all controls centered.
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Other efforts
● Unique envelope response to old single glazed windows and channels that were far from airtight. Winter wind blew right threw them into the spaces we were trying to heat and retain temp in. We sealed gaps in moveable aluminum frame components reachable from the ground with a non toxic, odorless, food grade sealant with a battery powered applicator.
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Loving the Environment● First Unitarian Society of
Minneapolis has saved in the contract period
● 26090 kWh ● 113 KW ● 10682 THM ● 27 MtCO2e ● $9500 ($13000 in the EPA
period thus far)● And has achieved● Thms per HDD to 2.6 ● An Energy Star Portfolio
Manager rating increase from 28 to 52 as of August 2011
● EUI rating improvement from 160 to 137
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