Anticipating a state executive order mandating that all new buildings and major renovations for state facilities be zero net energy (ZNE) starting in 2025, the California State Lottery saw the Santa Fe Springs office upgrade as an opportunity to test various ZNE design choices that would help them meet the upcoming rules. Deep energy retrofit strategies for the 12,840-square-foot warehouse include passive strategies such as daylighting and an energy-efficient envelope, as well as a rooftop photovoltaic (PV) system. The project was completed in September of 2015 and is the first of 11 lottery locations targeted for similar renovations.
“The essential goal is to design an efficient building and then see if you can meet the demand with onsite solar generation,” said Terry Murphy, Deputy Director of Operations, California State Lottery.
Lottery project managers, the design team led by LPAS Architecture + Design, and the California Department of General Services worked collaboratively to consider options to reduce energy consumption and maximize limited roof space for PVs. A daylight model helped to identify ways to lower lighting power density and a plug load study set a baseline for occupant power usage. High R-value wall and ceiling insulation offered the most dramatic reduction in energy use by cutting heating and cooling loads. An intelligent HVAC system uses an efficient, single-zone variable air volume (VAV) system. Controls and sensors manage the lighting and space conditioning needs. Dashboards offer occupants the opportunity to provide feedback and encourage energy-saving behaviors.
The entire retrofit process, excluding the purchase of the existing structure, cost $5.7 million. About 13% was applied to soft costs which accounted for all expenses, excluding construction. Construction costs accounted for $5 million of the total project costs – about $700,000 more than anticipated costs for a code building. The addition of PV panels accounted for $240,000 of this increase—4%. Analysis showed that more aggressive efficiency installations saved the project $48,000 in the costs of renewables.
- The amount of top lighting and PVs necessary for the project resulted in a substantial increase in roof load, which required an upgrade in structure. These improvements may have been more cost effective if an entirely new roof had been constructed rather than reusing the existing roof structure.
- Building operators learned the importance of involving commissioners throughout the entire construction process so that issues can be resolved before the building is occupied.
- There is an ideal balance point between energy efficiency and renewable energy generation which should be targeted. Given the decreasing cost of solar energy systems, the Lottery needed to consider the cost and trade offs of investing in energy efficiency versus additional PVs to achieve ZNE.