Energy Management Systems

Audit Identifies Sources of Hidden Energy Waste

July 15, 2013
Trans

With its eye on the future, the Vermont Community Foundation (VCF), a tax-exempt public charity based in Middlebury, Vt., is developing a plan to decrease its carbon footprint as part of an investment in environmental stewardship. Already, a portion of the energy the organization consumes is produced from bio waste, plus staff members recycle food scraps and other organic material in their very own vermicomposting system.

Challenge

The VCF oversees 600 funds and ranks among the top 10 percent of community foundations in the country. It manages more than $154 million in assets and awards $10.5 million in grants annually. Housed in a three-story, 9,000-square-foot facility, the foundation generates $25,000 in utility bills each year. A total of $3 per square foot is a high price to pay, especially considering that the HVAC system is relatively new. Because Middlebury offers no natural gas utility services, the building’s closed-loop water-source heat pump system is fueled by more expensive energy sources: electricity and propane. The VCF calculates it will spend $465,000 in total energy costs over the next 15 years, based on a conservative 3 percent annual price increase.

To get a handle on building energy use, the VCF called in Kilawatt Technologies, an energy management consulting firm based in Shelburne, Vt. The goals were clear: determine which energy-saving equipment best fit the needs of the facility, and calculate the potential return-on-investment of the new equipment.

Solution

To achieve these goals, Kilawatt Technologies employed a data-driven approach, deploying a variety of portable data loggers throughout the facility. Energy consumption data were collected over a three-week period, resulting in more than 250,000 measurements, including temperature, relative humidity, CO2 levels, motor run times, and electricity usage. Four types of temperature readings were collected: zone temperatures, heat pump discharged air, boiler, and main heat pump loop-heat injection.

“The data loggers we used made it possible for us to collect large quantities of diverse data in a short amount of time,” said Steven Antinozzi, COO, Kilawatt. “Fortunately, the devices come at a reasonable cost, making our data-driven tactics possible.”

Antinozzi and his team used a variety of deployment techniques that depended on installation locations and available surfaces. For example, they attached Onset HOBO® UX90 Motor On/Off data loggers directly to loop motors using the loggers’ integrated rare-earth magnets. For this deployment, they did not need a current transformer, since turning on the motor creates a magnetic field. Monitoring this magnetic field determined on-off cycles and run times.

To log zone temperatures, the engineers attached additional HOBO U12 loggers discreetly in office areas. They attached data loggers to metal ceiling vents with the self-adhesive magnetized rubber strips that came with the devices. Engineers set these data loggers to record every 15 minutes to monitor realized temperatures and setbacks.

Results

After charting and studying temperature data, Kilawatt engineers learned that the boiler fires at full power when outdoor ambient temperatures are as high as 60°F. Furthermore, amperage data led to the discovery that the cooling tower runs during the same time intervals as the boiler. This was understood to be due to the loop overheating. The data also showed that:

• Heat pumps and circulation pumps run during nights and weekends when the facility is unoccupied.

• Temperatures in office areas do not coincide with thermostat settings.

• CO2 spikes when the building is occupied, indicating poor ventilation.

• Loop motors, the facility’s largest point load, run during nights and weekends when the building is unoccupied. (These 2-hp motors consume 13,000 kW per year.)

• Heat migration from the boiler is substantial enough to heat the facility.

Kilawatt’s team recommended four key actions for the VCF based on collection and analysis of data logger statistics.

First, they suggested that the foundation install new HVAC controls — specifically, thermocouple-based thermostat, CO2, and humidity sensors. They also recommended a Web-enabled system for centralized and automated control of the HVAC system. At a cost of $15,000, the new controllers will eliminate unnecessary use of the boiler, cooling tower, and supporting equipment. After careful calculation based on data collected, Kilawatt projected that the controls would pay for themselves within four years.

The consulting firm also recommended that the VCF purchase an energy recovery ventilation system. At a cost of $50,000, this system will decrease heat pump use and allow for smaller heat pumps, while increasing ventilation.

The team further suggested building-shell improvements that, based on the data, would realize a realistic payback and improvement in comfort. The shell repairs included installing air-lock doors at the front entrance and low thermal-emissivity windows tuned for low external reflectivity and maximum retention of heat. These improvements will address the acute temperature problem experienced by office workers and the building’s overall outside air-infiltration issue. With the new doors and windows in place, the VCF will better manage its HVAC system and save energy costs. Engineers calculate these purchases will yield a payback, based on energy savings, in 14 years. The payback in occupant comfort, however, will be immediate.

Finally, the consulting firm recommended that the VCF use a solar photovoltaic energy solution to achieve its long-term net-zero goal. The suggestion was to install a southern Vermont ground-mount system with an annual output of 135,000 kWh. At a cost of $100,000, the new system is predicted to pay for itself within six years and leave the facility energy independent for the remainder of the building’s lifetime.

High-yielding and high-quality investments are few and far between. Capitalizing on energy efficiency and energy independence is smart business. With the implementation of these enhancements, the VCF theoretically could save (or yield, depending on one’s perspective) $215,000 over the next 15 years.

Publication date: 7/15/2013 

Want more HVAC industry news and information? Join The NEWS on Facebook, Twitter, and LinkedIn today!

Did you enjoy this article? Click here to subscribe to The NEWS Magazine

You must login or register in order to post a comment.

Multimedia

Videos

Image Galleries

2014 Energy Efficiency Forum

Highlights from the 25th annual Energy Efficiency Forum in Washington, D.C.

Podcasts

NEWSMakers: Rajan Rajendran

Rajan Rajendran, newly appointed director of the Emerson Innovation Center, talks about the new $35 million facility and how it will function on the University of Dayton campus. Posted on Aug. 29.

More Podcasts

ACHRNEWS

NEWS 09-01-14 cover

2014 September 1

Check out the weekly edition of The NEWS today!

Table Of Contents Subscribe

Venting R-22

The NEWS reported that a man received prison time for venting R-22. Should EPA step up enforcement?
View Results Poll Archive

HVACR INDUSTRY STORE

plumbing-hvac.gif
2014 National Plumbing & HVAC Estimator

Every plumbing and HVAC estimator can use the cost estimates in this practical manual!

More Products

Clear Seas Research

 

Clear Seas ResearchWith access to over one million professionals and more than 60 industry-specific publications, Clear Seas Research offers relevant insights from those who know your industry best. Let us customize a market research solution that exceeds your marketing goals.

DON'T MISS A THING

Magazine image
 
Register today for complete access to ACHRNews.com. Get full access to the latest features, Extra Edition, and more.

STAY CONNECTED

facebook icontwitter iconyoutube iconLinkedIn i con