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WattNode® Electrical Energy Meter Application Success Story

The Proximity™ Hotel in Greensboro, North Carolina, is the first hotel in the United States to receive LEED® (Leadership in Energy and Environmental Design) certification at the Platinum level from the U.S. Green Building Council®. Combining luxury with energy efficiency and environmental sustainability, the hotel places the highest priority on guest comfort. The owner’s goal is a sustainable, energy efficient hotel that never compromises guest comfort. The Proximity Hotel uses 40% less energy than a similar building without green building techniques. Renewable energy provides 35% of the electricity, and a solar thermal system provides 60% of the hot water. The building’s HVAC (heating, ventilation, air conditioning) equipment and refrigeration equipment minimize emissions that contribute to ozone depletion and climate change. These energy goals have been achieved at a luxury hotel with eight floors, 147 rooms, 5000 square feet of event space, and a restaurant. Proximity-Hotel.jpg

Business Case

Problem: To meet LEED energy requirements, the Proximity Hotel needed a measurement and verification (M&V) program. An M&V program verifies that actual energy consumption meets proposed consumption guidelines established during the LEED certification process. Solution: The Proximity Hotel modeled the building’s standard and projected green energy consumption. The final design model predicted an annual energy consumption 30% lower than a similar building designed to meet minimum building code requirements. The hotel then implemented a measurement and verification program as part of their overall energy efficiency solution, and the M&V process further reduced utility costs by USD 40,000 per year. Dr. Peter Rojeski, the owner of Measurement & Verification Services, developed the hotel’s M&V program. Dr. Rojeski, an energy efficiency consultant with extensive teaching and research experience in building energy management and energy conservation, specified the energy usage points to monitor, the data to be captured, the frequency of the data collection, and the data analysis plan. Dr. Rojeski also serves as the hotel’s energy efficiency expert. He analyzes the data in light of constantly changing energy efficiency technologies, quantifies the analysis based on the hotel’s energy models, and prepares reports that describe recommended operational tune-ups and opportunities for new efficiencies in financial terms. The Proximity Hotel has a dedicated energy efficiency team that reviews energy use data and recommendations, evaluates new technologies, and chooses cost-effective energy improvements and tune-ups. David Adams, president of Adams Environmental Systems, a company that specializes in building weather and M&V monitoring systems, performed the M&V systems integration work. At the start of the project, the Proximity Hotel had one gas meter and one electric meter. Adams Environmental Services built the weather station that monitors outdoor air temperature, humidity, and solar as well as the sensors that monitor indoor air temperature, humidity, and carbon dioxide levels at four locations in the hotel. The company specified the systems components needed to implement the data capture and inspection plan including the sub-metering system, the device network to transmit the data, and the data acquisition system. The company installed the components, set up the network, and programmed the components’ data capture, analysis, and display software. Adams Environmental Systems also maintains the data acquisition system. Sub-metering: The Proximity Hotel installed sub-metering equipment to measure energy use by heating, cooling, ventilation, lighting, and other important energy subsystems. Individual WattNode electrical energy meters isolate the performance of the air conditioning system’s two high-current chiller pumps. A third meter monitors the performance of the cooling fan, and a fourth meter monitors the performance of the two low-current hydronic hot water pumps. The benefits of WattNode electrical energy meters include:

  • Efficient communications
  • Support for three-phase variable speed motor drive (VSD / VFD)
  • Economical solution for monitoring multiple motors
  • Compact size
  • Support for wide range of current transformers (from 5 to 6,000 amps)
  • Support for voltages from 120 to 600 AC

Results: The M&V program with WattNode electrical energy meters helped the Proximity Hotel to:

  • Verify energy compliance
  • Capture and store of accurate energy-use information
  • Compile annual summaries of results for each system
  • Identify energy problems, areas for improvement, and operational tune-ups

Together with LEED green building techniques, a comprehensive measurement and verification program with sub-metering to isolate energy consumption by subsystem makes environmental and economic sustainability cost effective.

Implementation Summary

Systems Monitored Products Installed
Building gas Main gas meter
Building electricity Main electricity meter
Lighting Analog current clamp
Outdoor temperature, humidity, and solar Outdoor weather monitor
Indoor temperature, humidity, and carbon dioxide Indoor temperature, humidity, and cardon dioxide sensors
Solar hot water BTU meter
HVAC pumps (2) and cooling fan WattNode Modbus® electrical energy meters (3), WNC-3Y-208-MB
Hydronic hot water pumps (2) WattNode Modbus electrical energy meter (1), WNC-3Y-208-MB
Data acquisition network
Data acquisition system
Laptop computer with data storage
Kiosk for information display
Software for data acquisition, storage, analysis, and display
M&V Systems Design M&V Systems Integration
Measurement & Verification Services, Dr. Peter Rojeski, owner Adams Environmental Systems Inc., David Adams, President

For More Information

For a detailed discussion including implementation diagrams, see the Continental Control Systems white paper: Sub-Metering a Hotel for LEED Certification: CCS-Proximity-LEED.pdf. Special thanks to Dr. Peter Rojeski, Measurement & Verification Services, Dave Adams, Adams Environmental, and the Proximity Hotel, Greensboro, NC.

© 2011 Continental Control Systems, LLC. All rights reserved. Proximity™ and © 2011 Quaintance-Weaver Hotels, L.L.C. All rights reserved. Photo courtesy Quaintance-Weaver Hotels, L.L.C. All rights reserved. MODBUS® is a registered trademark of Schneider Electric USA, Inc. USGBC®, U.S. Green Building Council®, and LEED® are registered trademarks of the U.S. Green Building Council. WattNode® is a registered trademark of Continental Control Systems, LLC.