University of Miami is committed to safeguarding the environment, and in 2005 created the “Green U” initiative to become a community leader in the acquisition of environmentally responsible products and the practice of ecologically sound maintenance and operations procedures.

THE CHALLENGE

The indoor air quality (IAQ) was not at the level the facilities management team desired. Fitness centers not only generate a lot of carbon dioxide (CO₂) from people exercising, but the equipment and mats can off-gas volatile organic compounds (VOCs) and formaldehyde. Using increased outside air ventilation to improve the air quality inside was attempted, but it made it difficult for the HVAC systems to maintain a comfortable indoor temperature and humidity. Further, the energy consumption of the HVAC equipment was already quite high, and adding more hot, humid outside air ventilation would cause a significant increase in utility costs. Finally, increased outside air ventilation would result in an increase in fine particulate matter coming from the neighboring highway.

THE BUILDING

Located at the University of Miami Miller School of Medicine in downtown Miami, this 13-story building opened in October 2006. The UHealth Fitness and Wellness Center occupies the top two stories and spans 60,000 square feet.

The facility  includes a 15,000-square-foot fitness floor with over 100 pieces of state-of-the-art cardio and strength equipment, four group fitness instructional classrooms including a dedicated studio cycling room, and the Central Table Restaurant which serves fresh and healthy cuisine daily.

The building is connected to the neighboring clinical research building by a walkway on the 12th floor. The first 11 stories of the building are a parking facility and were, therefore, out of scope for this project.

Air quality is an important aspect of health, so it was a priority to the Wellness Center. In addition, the university has a strong commitment to the environment, and energy efficiency is a priority.

THE PROJECT

The center is served by four air handling units (AHUs) and a pool dehumidification system. The AHUs are connected to a central chilled water system that serves the medical campus. The scope of this HVAC Load Reduction^® (HLR^®) installation excluded AHU-1 and the pool area since this area requires special handling and is served by a separate AHU.

In June 2015, enVerid and Johnson Controls installed three of enVerid’s HLR modules in the mechanical rooms serving the Wellness Center.

The project was led by enVerid Systems along with three facilities management leaders from the university: Ron Bogue, vice president for facilities and services; Marcelo Bezos, director of energy management systems; and Carl Thomason, energy manager. In addition, the National Renewable Energy Lab (NREL) was contracted to perform independent measurement and verification (M&V) of energy savings and IAQ.

Before shipping the HLR modules, the enVerid project team assessed the HVAC mechanical environments, provided a detailed installation plan, and obtained necessary permits. They developed an energy metering and monitoring plan and collected and analyzed air samples for baseline indoor air quality.

In the installation phase, the enVerid project team selected and supervised electrical and mechanical subcontractors with the customer’s approval. Installation was completed with no disruption in HVAC service to building occupants.

Installation included wireless internet connectivity to feed air quality data into the enVerid Internet-of-Things (IoT) cloud-based platform for 24/7 monitoring. Each HLR module underwent its own acceptance test, and final acceptance tests for the building were completed after all modules were tested individually. Finally, an air test and balance was conducted by a third party, Air Balance and Diagnostic Co., to measure and adjust the outside air delivered to each zone.

The three HLR modules went live in July 2015. Each HLR unit includes patented sorbents housed in proprietary cartridges that adsorb CO₂, formaldehyde, and VOCs. The HLR module also has a set of sensors measuring temperature, relative humidity, CO_2, and VOCs. The HLR system interprets the output of these sensors using control algorithms to actively and automatically manage IAQ and outside air volumes.

MEASUREMENT METHODS

NREL validated and confirmed the energy savings of the HLR system. Energy consumption of the HVAC system was measured day by day to compare days with the HLR module operating versus when the HLR was off.

Measurements started on July 11, 2015, and were completed on Sept. 5, 2015. Energy consumption was measured using an energy meter installed by the building facility management. Chilled water consumption and outdoor conditions were also monitored.

When the HLR system was in use, outside air volume was reduced by 75 percent. The HLR off test was done while ensuring that the ventilation rates were set according to the Ventilation Rate Procedure (VRP; ASHRAE Standard 62.1 - 2013). In order to further confirm the savings, energy consumption was measured again in 2016, this time starting on Aug. 14 until Sept. 21.

For IAQ, contaminant concentrations were measured prior to the HLR module operation, then again after the HLR technology had been installed and running for at least one week. Indoor air quality monitoring was performed per U.S. Environmental Protection Agency (EPA) standards, and the results were analyzed by a third-party certified lab (Prism Analytical Technologies).

This investigation included environmental and indoor air quality sampling of temperature, relative humidity, carbon dioxide, speciated (separated by species) VOCs and total VOCs (TVOCs), formaldehyde, and particulate matter with aerodynamic size of less than 2.5 μm (PM_2.5). These include all the contaminants of concern typically found in buildings. The investigation included sampling at six different locations in the center. To prevent instrumentation based discrepancies, we tracked the instruments used for each type of measurement, along with the manufacturer reported detection principle, resolution, and uncertainty.

THE IMPACT

Using the HLR modules, the University of Miami’s Wellness Center used about 75 percent less outside air and thereby saved 828 ton-hrs per day of cooling — a 28 percent reduction in total HVAC energy consumption. As a result, the building is saving $19,500 each year in energy consumption.

The energy savings would have been higher if indoor temperature and humidity inside the building were kept constant when the HLR technology was on and off.  When the HLR system is off, indoor humidity is 10 percent higher, and temperature was also a couple degrees higher.

The HLR system reduced peak HVAC load by 56 tons, which corresponds to roughly a 41 percent decrease in total HVAC load. This savings impacts the “demand charges” on their utility bill, which in many locations, has a major impact on the overall cost of electricity. In addition, when the Wellness Center replaces the HVAC equipment in the future, the peak capacity required will be 41 percent less, providing significant capital expense savings.

The peak load reduction would have been even higher if the indoor temperature and relative humidity had been kept constant, as explained above.

Additional savings:

• Filters: A 75 percent reduction in outside air can double the lifetime of the outside air filters. Given that the University of Miami Wellness Center is next to a major highway, reduced filter changes can save hundreds of dollars each year.
   
• Reduced water consumption: University of Miami uses a central chiller plant, so specific water savings for the Wellness Center is difficult to confirm, but these savings could be thousands of dollars annually.
   
• Reduced Corrosion: A reduction of outside air intake reduces the introduction of saline latent outside air, providing several secondary benefits that include extending the useful life of the existing mechanical equipment and ductwork.

Improved indoor air quality (IAQ):

Using enVerid HLR modules, the minimum ventilation rate and results from IAQ (pollutant concentrations) showed compliance to ASHRAE Standard 62.1 IAQP. Contaminants (i.e., aldehydes, speciated VOCs, and CO₂) were successfully maintained below their established threshold values. In addition, by reducing the amount of outside air, less particulate matter and hazardous chemicals are brought into the building from the neighboring highway, providing a further improvement in air quality. A growing number of studies show that living near highways increases your chance of cardiovascular disease.

CONCLUSION

Faced with higher than desired energy costs and a commitment to high air quality and comfort, the Wellness Center turned to enVerid for help. The enVerid project team assessed the HVAC mechanical environments, provided a detailed installation plan, and obtained necessary permits.

In the installation phase, the enVerid project team selected and supervised electrical and mechanical subcontractors with the customer’s approval. Installation of three enVerid HLR modules was completed without disruption in HVAC service.

For more information, visit www.enverid.com.

Publication date: 8/21/2017

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