Architect’s Energy Bill Cut in Half

Challenge:

In just seven years, Integra Design Group, Architects & Engineers, PSC, San Juan, Puerto Rico, grew into one of the top 20 full service A/E firms in the Caribbean. By 2007, they needed more space.

For the new headquarters, Integra Partner Richard Cuebas asked his engineering consultant Jose Luis Marrero, San Juan, to design an HVAC system that would best meet LEED certification requirements, have the fewest outdoor units, quietest operation, best design flexibility, efficiency and system controls. Cooling the original 4,000 square-foot office was a direct-expansion (DX) single phase system with five rooftop units: two 12,000 Btu/h (ductless), two 36,000 Btu/h (ductless) and one 60,000 Btu/h (ducted).

Integra’s new 6,000-square-foot office in the Coliseum Tower includes work spaces with different thermal zones and 18-foot ceilings: reception, two conference rooms, offices for each partner, a design studio, accounting and project management departments, IT room, file room, a kitchen/dining area and rental office.

Solution:

Understanding how LEED credits for Energy & Atmosphere, Indoor Environmental Quality, and Innovation & Design could be achieved with VRF systems, Marrero recommended Variable Refrigerant Flow (VRF) zoning systems from Mitsubishi Electric Cooling and Heating Solutions, Suwanee, Ga. The system was designed to handle all of Cuebas’ LEED requirements: lower energy bills, a single outdoor unit (intelligently air-conditions up to 19 zones), humidity and temperature control, quiet operation, zone management, flexibility and Mitsubishi Electric’s advanced controls network, which allows local and remote control over the system.

“My former HVAC system was noisy, inefficient and costly to operate ($1,200/month),” Cuebas said. “The Mitsubishi Electric VRF zoning system has cut my monthly electric bills in half ($600/month), even though we have 2,000 more square feet and the Puerto Rico Power Authority recently increased our kW rates from 23 to 28 cents/hour. I am delighted with the cost savings, quietness, comfort, diversity, controls, simplicity and Mitsubishi Electric’s excellent sense of service.”