High Performing Buildings - Winter 2013 - (Page 25)

Lara Swimmer Above Open offices have operable windows, offering staff the opportunity for fresh air, daylight and views. Occupants can open windows when they desire and typically use a weather data dashboard on their computers to monitor outside conditions. Right Ground-floor community education and meeting facilities further extend Mercy Corps’ role within the community. Mercy Corps West, a local branch of the organization, holds classes on micro-financing and other community-focused programs several nights per week. to 30 tons of connected load. The focus on zonal heat exchange and maximizing diversity resulted in reduced capital system costs and increased energy savings. Controlling Comfort Consolidating Mercy Corps headquarters staff in one location also offered the opportunity to improve the comfort of the interior environment. Off-the-shelf solutions for adjusting comfort by zone and controlling the VRF system are suited for the building. Variable rates of air delivery from concealed fan-coils provides better airflow control than a typical fan-coil system. Operating in parallel with the VRF heat pumps is a dedicated outdoor air system (DOAS) that better responds to the building ventilation needs. The DOAS is sized to provide 30% greater airflow than the ASHRAE Standard 62.1-2004 requirements and minimizes ventilation as necessary with CO2 sensors in all occupied areas. Rooftop gas-fired units with heatwheel heat recovery provide the variable rate of ventilation delivery through variable air volume (VAV) terminal units, which serve ventilation zones that are defined by schedule and occupancy type. Highdensity zones such as conference rooms are provided with dedicated VAV terminal units and CO2 sensors. The parallel DOAS system also allows for economizer air delivery separate from the distributed fan-coils. In Portland there are more than 1,300 occupied hours per year when outside air conditions are favorable for air-side economizer cooling, enough to warrant an amendment to the state’s energy code. The code exception allows for heat exchange systems to be exempt from the economizer requirements, but Mercy Corps’ system uses both in parallel. In addition to providing free cooling, the parallel ventilation system allows for a simplified sequence of control for the morning warm-up. Prior to building occupancy and VRF system start-up, the DOAS is converted to a recirculation air system and uses cost-effective natural gas to warm up the building from the overnight setback temperatures. In the same manner, a nighttime flush sequence is simplified during the summer. The design team chose parallel DOAS systems over series DOAS systems for the ease of sequencing. Winter 2013 HigH When the building is occupied, control systems must also respond to ventilation air introduced through operable openings. Occupants typically use a weather data dashboard on their computers to monitor outside conditions while they are working. If they feel it is a nice day and want to open the window, they are free to do so. The roof monitor is activated when it isn’t raining and the outdoor air temperature is above a specified temperature setpoint. Building EnvElopE Roof Type Single ply membrane on tapered insulation Overall R-value Average: R-30 (minimum: R-20); Green roof: R-50 Reflectivity 80% at single ply; N/A at green roof Walls Type Existing masonry bearing and new framed walls Overall R-value Existing: R-12; New: R-15 Glazing Percentage Existing: 20%; New: 35% Basement/Foundation Slab Edge Insulation R-value R-10 Basement Wall Insulation R-value R-10 Windows Effective U-factor for Assembly Existing: 0.3; New: 0.37 Solar Heat Gain Coefficient (SHGC) 0.27 Visual Transmittance 64% Performing Buildings 25 Jeff Amram

Table of Contents for the Digital Edition of High Performing Buildings - Winter 2013

High Performing Buildings - Winter 2013
Commentary
Contents
Kensington High School for the Creative and Performing Arts
Mercy Corps World Headquarters
Hood River Middle School Music and Science Building
UC Davis Health and Wellness Center
Gateway West Sustainable I
Technologies on Display
Advertisers Index

High Performing Buildings - Winter 2013