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Project of the Year – International DPR Net Positive Energy San Francisco

Project of the Year – International DPR Net Positive Energy San Francisco

Project of the Year – International
DPR Net Positive Energy San Francisco Office, USA - Elementa Consulting, Member of Integral Group

Back to 2017 BPA Winners Overview

DPR Construction is leading by example with its award-winning net positive energy San Francisco office retrofit. The fully electric project delivers exceptional energy efficiency and an impressive 94% occupant satisfaction rating. It has zero onsite combustion and generates more renewable energy from the roof-mounted solar panels than it consumes.

The two-storey, 20,010 sq ft building provides space for 90 people in offices, conference rooms, a central atrium, break areas, kitchen, and a fitness centre to promote health and wellbeing.

The team reduced the envelope load and thermal asymmetry through enhanced insulation and electrochromatic dynamic glazing on skylights, which reduces the fullload operating hours of the active mechanical system. A light sensor on the roof actively adjusts the tint of the glass based on outdoor light levels.

Dedicated outdoor air systems with pre and final filters and heat recovery deliver 30% more fresh air to the occupants than ASHRAE 62.1 2010 requires. The building is heated and cooled with user-controlled variable refrigerant flow (VRF) systems. Air movement is further enhanced by  large ceiling fans with three ‘living walls’ removing VOCs (volatile organic compounds) from the air.

The team was faced with the challenge of retrofi tting a building to net positive energy on a budget of $200/sq ft, within a total design and construction schedule of 10 months, in a dense urban environment, surrounded by adjacent, taller buildings and a heavily trafficked road.

The office renovation included replacing the end of life gas-fired boiler and roof top units with a VRF system that enables heat to be transferred from spaces requiring cooling to spaces that require heating (and vice versa) allowing for improved thermal zoning and control of the building and higher heating and cooling efficiency.

Refrigerant runs from rooftop condensing units through branch selectors and then out to fan coil units serving the spaces. The all-electric VRF system, which includes heat recovery, contributed to a 37% reduction in HVAC energy consumption.

The team focused on driving down envelope loads and increasing roof insulation, to allow for the use of daylight harvesting through skylights and still achieve the EUI (energy use intensity) target.

The air handling units are designed to take advantage of the temperate climate through air-side economising and heat exchanger by-pass dampers, allowing the outdoor ventilation air to be filtered.