The Tower Companies: Blair Office Building
The Blair Office Building is a multi-tenant commercial office building, built in 1963, with seven-stories above grade and one floor below grade. The Blair Office Building is located in Silver Spring, Md., just steps from the Metro Station at the intersection of Colesville Road and East-West Highway and on the border with Washington, D.C. The building is 100 percent occupied and home to 13 different office tenants, which include nonprofits, service firms, and medical offices. It is a part of The Blairs District complex, a 27-acre mixed-use community with over 1,100 apartments and nearly 100,000 square feet of retail. The Tower Companies is the developer, owner, and manager of Blair Office Building as well as the other properties included in The Blairs District.More
The goal of this project was to find a way to take an existing 1960s, Class C, multi-tenant office building – of which there are many in Maryland and around the country – and transform it into a building that is a leader in energy efficiency, even when compared to modern buildings. The Tower Companies strives to lead by example on environmental responsibility and has integrated sustainability into the business operations and DNA of the organization. Before this project was implemented, the team had already implemented a robust energy management program to establish benchmarks and goals, develop low-cost energy conservation measures, and track progress through the use of real-time data, analytics, training, and engagement. The team had a challenge because the building was limited in energy savings opportunities through only low- and no-cost energy conservation measures; like many older buildings, it did not have a building automation system (BAS) and did not have controls for any office fan coil units.
The Tower Companies spent several years optimizing outdated systems and implementing a portfolio-wide strategic energy management program to establish benchmarks and goals, develop energy conservation measures (ECMs), and track progress through real-time data, analytics, training, and stakeholder engagement. In May 2015, the Maryland Energy Administration (MEA) awarded The Tower Companies with a grant to fund three ECMs to further produce energy savings opportunities: (1) Add time-of-day controls to building perimeter units; (2) Add new VFDs to loop pumps; (3) Add time-of-day scheduling to cooling tower and open loop pumps with high closed loop temperature override. The project was completed in October 2015 and during the first 12 months after implementation, the building recognized approximately $40,000 in total cost savings. These cost savings are equal to the total investment for the entire project and, when deducting the grant from the total upfront cost, the project yields a six month simple payback.More
Previous upgrades in the building featured low- and no-cost ECMs such as lighting system occupancy sensors, programmable thermostats in self-contained units (SCUs), and time clocks on the exhaust fans and water fountain compressors, as well as operational changes including seasonal night audits and day walks and tenant engagement focused on improving behavioral efficiency. From 2012-2014, the building saved 165,000 kWh, but there was a limitation to how much savings were still possible without a BAS. Additionally, Tower’s team engaged the building’s tenants through Earth Day presentations and a training that taught office tenants how to turn off fan coil units at night, but behavior changes did not lead to the energy savings the team had hoped for. The MEA grant facilitated the next step in optimizing the facility’s operations and identifying the biggest remaining areas to decrease energy consumption without having to make a significant investment in this older, Class C property.
The three ECMs included:
- Added time-of-day controls to perimeter units. The building’s original pneumatic control system was obsolete and beyond repair. The only control available to the perimeter water-cooled heat pumps was the local controller on each unit. As a result, the 256 units were running continuously, unless someone turned them off manually. At night, perimeter unit settings were typically left untouched as tenants left for the day. The lack of controls increased compressor runtime and shortened the life of the unit, and when the building was converted to a water-cooled heat pump system in 1987 a boiler was not installed. Therefore, all of the building heating was done through electric resistance heating located at each individual perimeter heater. To address the large energy consumption at night, the perimeter heat pumps were put on individual contactors controlled by a digital programmable time clock. This turns off the units at night (based on lease hours) while providing the ability to customize the operating hours on an individual basis for each tenant.
- Cost - $18,900
- Estimated Energy Savings (analyzed for the MEA Application) - 260,000 kWh
- Estimated Cost Savings (analyzed for the MEA Application) - $32,225
- Added new Variable Frequency Drives (VFD) to loop pumps. The condenser water system is served by an open cooling tower loop and a closed building loop, joined by a heat exchanger. The closed loop consists of two 15-horsepower pumps and the open loop consists of one 20-horsepower pump, with an additional pump for standby on each system. Both systems consist of one high efficiency pump (94 percent) and one standard efficiency pump (87 percent). VFDs were added to the pumps to modulate flow through both loops by reducing the speed of the pumps during off-peak hours. The pumps run at full-speed from mid-June through mid-September. The closed loop pumps run 24/7, and the open loop pumps run from 6am to 10pm, as needed by the cooling tower.
- Cost - $12,500
- Estimated Energy Savings - 99,400 kWh
- Estimated Cost Savings - $12,325
- Added time-of-day scheduling to cooling tower and open loop pumps with closed loop temperature override. The open loop pumps and cooling tower would run continuously. A control system was added to control the pumps and the cooling tower based on the time of day. A high temperature override was provided to energize the condenser water system in the event that the closed loop temperature exceeds a high temperature limit set point during unoccupied hours. The open loop consists of one 20-horsepower pump, with an additional pump for standby. The system consists of one high efficiency pump (94 percent) and one standard efficiency pump (87 percent).
- Cost - $13,500
- Estimated Energy Savings - 48,300 kWh
- Estimated Cost Savings - $6,000
Since implementing the project, The Blair Office Building achieved tremendous energy savings and a payback in six months, due to the fact that the MEA grant helped to pay for almost half of the cost of the project. The total off-hours load (when the building was not occupied by tenants) was reduced by over 50 percent. Additionally, the building’s ENERGY STAR® Portfolio Manager score has continued to rise since implementing these measures, increasing by 13 points in the first year of implementation to a score of 70. The Tower Companies later achieved ENERGY STAR Certification for the building.More
In addition to the tremendous energy savings, the property and engineering teams did learn the importance of actively engaging and communicating with building tenants and occupants. For example, operating HVAC equipment by request only after normal business hours and on weekends is included in the green leases that The Tower Companies executes with its tenants to reduce operating costs. However, prior to adding the time-of-day controls to the office perimeter units on each floor, HVAC units would often run during the evenings and weekends, outside of normal leasing hours, which clients came to expect all the time. After the new measures were installed, the property team notified tenants of the change but they did not raise immediate concerns. Later, multiple building tenants noticed the change when they came to the building to work outside of lease hours, and without notifying the engineering team. During the summer when outdoor temperatures were at peak levels, and the perimeter units were no longer operating due to the new timers, several office tenants were disappointed to come into their office spaces to find their spaces were not being conditioned. Due to tenant requests, the building team had to operate some of the spaces during weekday off-hours and weekend hours, which was not considered in the initial analysis of the project when evaluating for energy savings.
Additionally, despite The Tower Companies successfully engaging building clients through green team meetings and educational flyers that explain the importance of energy reduction, the dramatic energy savings of measures such as these illustrate that technology sometimes wins over behavior change as the most effective way to improve building performance.Less