Zero Energy Certified

DESIGN ENGINEERS NET ZERO ENERGY IMPROVEMENTS

VITAL STATS
Certification StatusZero Energy Certified
LocationCedar Rapids, IA, USA
TypologyRenovation
Project Area14,800 SF
Start of OccupancyOctober 2016
Owner OccupiedYes
Number of Occupants45
PROJECT TEAM
OwnerDesign Engineers, PC
Project ManagerDwight Schumm (Design Engineers, PC)
General ContractorEagle Point Solar
Photo Courtesy of Design Engineers
BUILDING SYSTEMS INFORMATION
Wall R value and section specification16. 4″ face brick, air space, 2″ polystyrene board insulation, moisture barrier and wall sheathing, 6″ metal framing, 5/8″ gypsum board
Roof R value24
Floor R value10
Window to Wall Ratio34%
Window U Value0.42
Window DescriptionDouble pane 1″ thick insulating units with low-e coating on outside glass and 0.5″ air gap. Aluminum frames with thermal break.
MECHANICAL HEATING AND COOLING

Ground source heat pump with total energy recovery of building exhaust air and variable speed ground loop pumping.

MECHANICAL VENTILATION

Energy recovery ventilator with total energy recovery effectiveness of 70%. Outdoor air from ERV is ducted to the return of the individual ground source heat pumps. Low return within each zone increases outdoor air delivery effectiveness (20% less OA).

LIGHTING

LED and fluorescent lighting with daylight and stepped dimming and occupancy sensors.

USER LOAD REDUCTION STRATEGIES

Programmed tight control of common are occupancy sensors to reduced fixture on-hours. Installed occupancy-controlled power strips. Encouraged employees to shutoff computers at end of day. Also encouraged employees to adjust interior shading devices at appropriate times to utilize the maximum amount of daylight. Programmed permanent setback mode in unused offices. Increased unoccupied mode for heat pumps to better match hours of employee occupancy.

Photo Courtesy of Design Engineers
RENEWABLE PRODUCTION SYSTEMS INFORMATION
Panel Array Size103 kW
Panel Quantity360
Type and BrandCrystalline Silicon, Suniva
Inverter Quantity6
LocationRoof
Ownership DetailsSame ownership as project
PERFORMANCE
Actual energy use during performance period128,599 kWh
Actual energy produced during performance period128,637 kWh
Net Energy Use-38 kWh
EUI29.6 kBTU/sf/yr
Photo Courtesy of Design Engineers
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