The stated goal of Zero Net Energy performance for the new Massachusetts Wildlife and Fisheries Headquartersrequires that the building mechanical and electrical systems be designed to consume the lowest possible amountof energy to satisfy desired indoor environmental conditions.  A comprehensive approach to system optimizationwas employed, which utilized cost-effective and practical measures to reduce energy use.

Control of all basic mechanical functions in the facility, for both control equipment and local zones, is carried out through a distributed digital control (DDC) system.  A central display was provided as part of the DDC system to present in real time the building system operation and energy performance.  Display is menu driven with multiple screen views and custom graphics.  This is integrated with the following to provide a complete unifed “picture” of the building:

1. Solar Electrical Generation
2. Ground Source Heat Pump System
3. Lighting Control System
4. Electrical Metering: Demand, net, and sub-meter of building systems

The system approach consists of central ground source heat pumps with an innovative free-cooling loop to provide hot water and chilled water to serve space conditioning. Radiant delivery of heating and cooling through in-foor and ceiling panels were used.  Radiant systems are coupled with a Dedicated Outdoor Air System (DOAS) to satisfy ventilation requirements.  A building-wide mixed-mode natural ventilation system is utilized to keep the requirement for mechanical cooling to a minimum.  A roof-mounted photovoltaic (PV) system provides renewable on-site electric generation to offset building electrical consumption.  Domestic hot water is produced by a heat pump water heater fed from the ground loop and powered by the PV system.

A Photovoltaic Panel system has been utilized, that consists of a series of rack-mounted PV panels, angled for optimal performance.  A system of nominal 290 kW rating was required in order to meet the program directive to achieve ‘net zero’ electrical usage from the utility grid.

All lighting in the building was selected for high effciency operation.  Optimization of available daylight and lighting design is intended for a net result of electrical lighting being off as much as possible when there is available natural light.  All building lamps are fuorescent or LED.  No incandescent lamps were planned.  LPD (Lighting Power Density) goal for the building is to reach 70-80% of the prescribed values established under ASHRAE 90.1-2004.

Each enclosed space has occupancy sensor control for lighting with a local override switch to shut the lights off.  Daylight sensors in each perimeter zone dim the lighting fxtures when adequate sunlight is available.  Open spaces have daylight and occupancy sensor controls.  Open, multi-level public spaces are designed for passive daylight harvesting.  Daylight sensors in this space control the use of all electric lighting installed.