The building envelope can be thought of as a shell or barrier separating interior spaces from the outside environment. Roofs and walls protect inhabitants from the elements, while windows transmit light, views and ventilation to occupants.
The building's insulation is comprised of both old and new systems. The existing building is fabricated predominantly from tilt-up concrete. Non-CFC rigid foam added to the existing walls, often referred to as an "Exterior Finish Insulation System," or "EFIS," enhanced the walls' insulation value from R-7 to R-11. The new exterior walls combine foil-backed fiberglass batt insulation and EFIS to achieve an R-value of 11. These insulation systems reduce heat gain and loss through the building walls by 50%.
Roof insulation in the remodeled east and west sections of the ERC provides an R-value of 38, double the R-value of traditional California roofs. Insulation on the new center roof section has an R-value of 30.
Poor caulking and sealing of building wall seams and connection points result in substantial energy loss in buildings. A "no-leak, no-loss" specified design, along with carefully executed installation, reduces infiltration.
The ERC air distribution system was carefully planned for accurate supply and return. State-of-the-art diffusers and duct work design enhance the efficiency of mechanical systems. One of the key features of this system is the Variable Air Volume controls placed strategically throughout the building. Careful installation from the supply fan to the diffuser further minimizes energy use.
The ERC displays both old and new roof systems. The old, traditional roof is made from hot asphalt and toxic adhesives. The new second-story roof membrane, which covers one-third of the building, is mechanically fastened, eliminating the need for heat equipment, hot asphalt, and toxic adhesives and sealants. A highly reflective white roof coating dramatically reduces captured heat, thereby decreasing air conditioning needs by 10 to 40%. This low-maintenance roof is also highly resistant to extreme temperatures, puncture and oxidation.
Low "e" Glass. In order to reduce radiant heat gain or loss, low "e" (emissivity) glass was used in all windows. The windows are gas-filled and dual-glazed with a "heat mirror" sheet, a transparent material that allows light, but little heat, to penetrate during warm months and retains heat in winter. These windows not only provide energy savings but also acoustic benefits by minimizing external noise.
Natural lighting reduces electrical lighting needs by as much as 80%
The use of high-efficiency T-8 fluorescent lamps, electronic ballasts, daylighting systems, and light and occupancy sensors reduces electrical energy requirements for ambient and task lighting by 47%. Reducing the use of electrical lighting and heat-emitting lamps also decreases the cooling load during the summer months. This savings is partially offset by a slight increase in heating load during winter months, due to the absence of waste heat from traditional lighting.
Additional monitoring points were added to the equipment to again measure the energy performance of the units. The Desiccant System uses two packaged units containing a desiccant and thermal wheel to condition the outside air temperature and humidity to meet comfort conditions inside the building. The space served by these units contains a small kitchen. The desiccant units control the humidity in the space and allow the dry-bulb supply-air temperature to rise above the traditional 55F DB when it is not required.
The units use a gas-fired hydronic heater to regenerate the desiccant and to provide space heating. The result is a unit that primarily consumes gas to provide heating and cooling, making it extremely cost-effective during the summer months, when electricity typically is most expensive. The main HVAC system consists of a 90-ton central plant (three 30-ton, gas-fired, double-effect chillers/heaters connected in parallel) serving two main air handlers.
The air distribution system consists of a variable air volume (VAV) system using VFCs on the main supply fans and VAV boxes with hot water-reheat controlling the air flow to each zone. Both air-handling units use two exhaust air fans along with motorized exhaust, return and outside air dampers to facilitate the economizer cycles. The central plant is a four-pipe system with the chiller/heater units using three-way changeover valves to supply chilled water to cooling coils located in the air-handling units and hot water to the VAV boxes.
Daylighting and Building Orientation.
Maximum use of "free" natural light reduces the need for energy-intensive electrical lighting. Daylighting techniques and proper building orientation allow for considerable mechanical system downsizing. Although the former building's orientation limited solar benefits, the design team worked closely with mechanical engineers to optimize the solar orientation of the second-story addition in order to cut electrical lighting needs.
During full sunny days, natural lighting from the second story reduces electrical lighting needs by as much as 80%. Lighting usage prior to the building's redesign was above 1.7 watts per square foot. Daylighting and advanced lighting techniques decrease lighting requirements by 40%, to just under one watt per square foot.
Skylights (So-Luminaire Active Daylighting Systems).
Three skylights in the main ERC first-floor corridor incorporate a sun-tracking system that uses mirrors, reflective light ducts and efficient diffusing lenses to create a technologically advanced interior lighting system for daytime use. One So-Luminaire skylight can eliminate the use of over two million watt-hours of electric lighting per year. The skylights pay for themselves through energy cost savings after two to five years.
Kalwall Translucent Clerestory. Translucent window wall sections are strategically placed to allow natural daylight to saturate interior spaces, providing a soft ambient light while minimizing heat transfer and loss.
T-8 Fluorescent Lamps and Electronic Ballasts. T-8 fluorescent lamps and electronic ballasts provide most of the ambient and task lighting in the ERC. T-8 lamps are 25% more efficient than standard T-12 fluorescent lamps. Their one-inch diameter allows for the design of smaller, more compact fixtures with improved photometrics. Electronic ballasts increase lamp life and reduce heat normally generated by magnetic ballasts, ultimately lowering air conditioning needs and energy bills.
Occupancy and Light Sensor Controls. Occupancy and light sensors are used throughout the ERC. The sensors have a significant impact on energy savings, estimated between 35 and 60%. Infrared occupancy (motion) sensors, which switch the lights on and off, are installed in most interior spaces of the ERC.
In addition, in rooms with windows, light sensors continuously adjust the amount of electrical lighting used, depending on natural light levels. Through energy savings, occupancy and light sensors have a payback of one to three years.
While most buildings use only one type of heating and cooling system, the ERC uses both natural gas and electric systems in order to maximize efficiency and lower energy costs.
Use of energy-efficient design and technologies has reduced the building's cooling energy needs by 54%. Four types of equipment - indirect/direct evaporative cooling, desiccant units, absorption chillers/heaters and package units - create a combined system that balances the uses of electricity and natural gas. By controlling peak uses of both energy sources, mechanical system sizing and energy costs are reduced.
The ERC's air conditioning system consists of portions of the existing building system, including two 30-ton and two 7.5-ton gas-fired chillers/heaters, coupled with new equipment to meet projected needs. Using the existing air conditioning system significantly reduced new equipment and disposal costs.
Indirect/Direct Evaporative Cooling System. Indirect and direct evaporative cooling serves the new portion of the ERC's first floor, including the main hall and lobby. Large quantities of outside air are brought into the space due to its high occupancy levels. Indirect/direct evaporative cooling uses a wetted media to cool air, both directly and indirectly (using a heat exchanger).
Although the system operates using solely evaporative cooling for most periods, it is connected to an electric, air-cooled condensing unit, which allows for additional mechanical cooling during extremely hot weather. On a seasonal basis, the system is 50% more efficient than a conventional system.
Two dual-wheeled desiccant cooling units have been installed in part of the building to improve indoor air quality. These units service the ERC's multi-purpose room and catering kitchen. By removing moisture, the desiccant units decrease the potential for growth of the biological contaminants which accompany moist air. They are designed to intake 100% outdoor air when temperature and humidity levels are appropriate.
While moisture removal in conventional air conditioning systems typically requires significant energy consumption, the desiccant units reduce conventional mechanical cooling requirements to these sections of the building by approximately 40%.
The ERC utilizes three 30-ton natural gas-fired, double-effect absorption chillers/heaters to serve the majority of the existing building areas on the first floor and the entire second story in the new Center section. These CFC-free chillers reduce electrical demand and keep harmful ozone-depleting substances out of the atmosphere.
While most electric air conditioning systems still use CFC-based refrigerants, absorption chillers are more environmentally benign in that they use water as the refrigerant. Absorption chillers/heaters also supply the majority of the Center's heating needs. The chillers are piped to air-handling units that feature outside air economizers and variable air volume distribution.
Package units for electric cooling and gas heating serve different parts of the Center, including a Large Equipment room. These advanced units have a Seasonal Energy-Efficiency Rating (SEER) of 11.0, exceeding CEC requirements by 10%.
Variable Frequency Drives
All major air-handling systems in the ERC use variable frequency drive technology to conserve energy. This feature varies the speed of the fans depending on cooling or heating demand. Conversion from constant volume to variable air volume distribution (VAV) results in a 75% reduction in fan energy requirements. Fan energy is generally the third largest energy user in commercial buildings, behind lighting and cooling.
In addition, one of the drives being demonstrated is a "clean power" unit that virtually eliminates the need for the costly electronic harmonic filter systems typically required in data processing and other power-sensitive operations.
Make-up Air Unit
The make-up air unit (MAU) serves the large equipment demonstration area. When the exhaust fans are working to remove heat from the equipment, the MAU draws in outdoor air to make up exhausted air and maintain appropriate air pressure in the room. The unit employs a gas-fired heater and direct evaporative cooling module, which temper the air in lieu of costly mechanical cooling.
A compensating hood, located in the roof above the ERC's Catering Kitchen, acts as a self-contained exhaust and make-up air system, reducing the amount of electrical fan energy required to control kitchen ventilation.
A computerized energy management system optimizes energy use at the ERC by monitoring and controlling the building's heating, ventilation and air conditioning systems through an extensive network of more than 230 data-gathering sensors. The system incorporates equipment from both the existing building and new equipment.
The Center utilizes a new generation of advanced client/server technology that brings high-end functionality to the operation and maintenance of the Center. With this Computerized Maintenance Management System (CMMS), the Center's state-of-the-art equipment can perform more effectively, its operation runs more smoothly, and it is able to maintain maximum performance and cost-efficiency.
In addition, this system allows for the interaction of building engineers and managers, in a relational database, to track and analyze equipment availability, total equipment downtime, and operational downtime to identify the root causes and frequency of failures and downtime. The Center's staff manages everything from work orders and job plans to purchasing and inventory. With this type of operation and maintenance plan, the ERC can implement sound management principles such as Total Productive Maintenance (TPM) and Total Quality Management (TQM).
The Center is able to keep and update records of all of its equipment. It can add new pieces of equipment to the database, along with their relationship to other equipment, and track maintenance costs, and enter and review meter readings. In addition, the Center is able to add "as-built" computer file drawings, pictures of equipment and a database history of all of the equipment at the ERC.
Preventative Maintenance (PM) Masters are used to generate work orders for regularly performed tasks on either an elapsed-time or metered basis. Predictive maintenance is provided through associating PM Masters with preset alarm conditions. In addition, work orders are a central element of the Center's operations and maintenance management system, coupled with job plans, which are utilized as a detailed description of work to be performed on a job.
Along with job plans, which typically include procedural descriptions, labor and tools used on the job, the Computerized Maintenance Management System details work, generates work orders, schedules work and provides a comprehensive way of operating and maintaining the Energy Resource Center.
A computerized energy management system optimizes energy use at the ERC.
All 34 Compaq(tm) computers installed on the first floor of the ERC are "Energy Stars." Computers designated by the U.S. Environmental Protection Agency as Energy Stars will switch to a low-power state when left inactive. In this state they draw 30 watts or fewer, for a 50 to 75% reduction compared to normal power draw.
- Solid waste landfills. Solid waste landfills across the country are reaching capacity and natural resources are being depleted at a rapid rate. To reduce waste and conserve resources, the U.S. Environmental Protection Agency promotes the following waste management hierarchy: source reduction (decreasing the amount of waste generated in the first place), reuse and recycling, followed by incineration and landfilling.
- Waste reduction. The State of California has called for the reduction of waste disposal in the state by 25% by 1995 and 50% by the year 2000. Recycling will become viable only if markets are created for end products made from post-consumer recycled waste.
- Water conservation. California has experienced drought conditions for 7 of the last 20 years. In response, the Metropolitan Water District cut water deliveries by 31%, forcing local agencies to impose rationing; higher user fees; penalties for exceeding allotments; moratoriums on new water connections, construction and landscape uses; and ordinances requiring low-flow toilets and fixtures in new and remodeled buildings. Due to our arid climate, expanding population and limited water supplies, water conservation must become a way of life for Southern Californians.
- Lumber use. Building construction is responsible for one-fourth of the demand for forest resources. The use of exotic tropical timber, such as teak and mahogany, contributes to the destruction of rain forest ecosystems, which are disappearing at a rate of one acre every second. Less than 1% of tropical timber harvested in the world is certified as "sustainable."
- Drilling and mining. Environmental impacts from drilling and mining include landscape destruction, toxic runoff from mines and tailing piles, and air and water pollution from processing.
The ERC Approach
The ERC building design approach seeks to preserve and minimize the use of natural resources by decreasing consumption, reusing materials, recycling, incorporating products that contain post-consumer recycled content, and sustainable sourcing that does not threaten fragile ecosystems.
Specific steps include reusing materials from the former Southern California Gas Company office building, recycling demolition waste, using recycled and reused building materials, installing water conservation devices, and avoiding the use of tropical hardwoods.