Renewable Energy Options for
Many Federal facilities include warehouses or other buildings used for storage service such as motor pools or groundskeeping, hangars, or other spaces that are frequently open to the outside and have only semi-conditioned spaces. Use of daylighting and solar ventilation preheat are prime technologies for these type of spaces, but other technologies may also warrant consideration.
Daylighting can keep lighting costs down dramatically in warehouses and can be as simple as implementing translucent roofing materials or skylights. Direct light and glare should be minimized, but natural lighting can be very cost-effective versus lighting broad spaces.
In heating-load dominated climates, solar ventilation air preheating can reduce heat loads substantially and are very economical. This technology, which uses specially-designed siding to draw in and preheat ventilation air, is particularly effective in spaces with high air turnover. Passive solar design can also be built into warehouses, ranging from simple solutions such as light-colored roofing to overhangs on south facades and Trombe walls to capture thermal energy.
These types of facilities should be assessed to determine if there is enough hot water load to warrant a solar water heating system, which may be the case if the facility includes showers or locker rooms, or if the function of the facility has high-temperature water uses. Photovoltaics (PV) can be integrated with any facility, but may be more cost-effective where the facility needs stand-alone power or is located a distance from the existing power lines.
If either solar water heating or PV is considered, the structural integrity of the facility needs to be examined to determine if it can handle the additional load on the roof. Both solar thermal and PV systems can add as much as 6 lbs/ft² in static load to the roof depending on the system type and how it is mounted. The dynamic loads of a system also need to be considered, especially wind loads on the new system. Often ground-mounted or lightweight systems will make more sense in a warehouse.
In any facility, energy efficiency should be a priority in the design. Warehouse and service buildings can greatly reduce their energy use with proper design. Technologies can include low-voltage lighting, proper lighting controls, radiant heating instead of forced air, and the use of low-energy options for ventilation such as high volume fans. The Whole Building Design Guide has information on the efficient design of warehouses and hangars.