March 25, 2009
For over a year CB Engineers has been immersed in the design and consulting for Disney Resort project. This new concept which incorporates a resort, timeshares, and hotel, covers almost one-million square feet of conditioned area set on the beautiful island of Oahu in Hawaii. With high end restaurants, spa, meeting rooms, and support spaces, the project is a self contained entertainment and vacation destination.
We were very excited about this project and along with the Owner, recognized the opportunity it presented to integrate a number of key design features into the project to improve the overall sustainability of the complex. As expected the overall energy consumption is a critical aspect of the projects environmental footprint, and anything that could reduce energy use was strongly considered.
The project is anticipated to consume a great amount of energy. Based on energy models created for the baseline building, energy savings measures would consume over 36-million kWh of electric energy each year! For comparison, an average American home in 2007, used 10,700-kWh of electricity in the year. The project itself uses enough electricity to power approximately 3,400 homes a year!
The local hot and humid climate impacts the buildings air conditioning requirements and the treatment of outdoor fresh air for ventilation is a major consumer of energy. The current design overcomes this handicap by using a dedicated outdoor fresh air delivery system, which treats the outside air and delivers it directly to the spaces. A standard ventilation system uses a weighted average calculation that results in over-ventilation of numerous zones. The dedicated outside air system removes this problem and although it requires an additional air-handling unit, it saves a significant amount of energy. To complete the cycle, the energy that is normally lost from a building through exhausted air is recaptured in this project.
Refrigerant based heat pipes using no moving parts enable the transfer of energy from one air stream to another and have been implemented to capture the sensible energy in the outgoing exhaust air and transfer it to the incoming air. The reclaimed energy (heat or cooling) reduces the facility’s demand for energy.
The complex has a large central cooling and heating plant in which high efficiency chillers are utilized resulting in significant energy savings. As part of the central plant, Templifier heat pump chillers serve as the building hot water generators providing an instant 300% improvement over standard electric water heaters.
Natural gas is not readily available at the project location, so gas fired boilers and water heaters are not feasible. By using the electric heat pump cycle with its high coefficient of performance, the facility captures significant energy savings and the heat pump chillers are available as backup for the chilled water plant.
On the electrical side, high efficiency lighting fixtures and lighting design has been implemented as well as facility wide lighting controls. The lighting controls include occupancy sensors for the intermittently occupied spaces and all site lighting is controlled by photosensors that react to ambient light levels. Even the electric power infrastructure contributes to the overall building efficiency by utilizing a CSL-3 transformer which is a high efficiency transformer. Through the transformer construction materials, windings and design, this product ensures that the incoming power is efficiently utilized by minimizing the energy lost in the voltage conversion.
Through these measures, the current building design utilizes just under 20% less energy than the basecase building. Although this is still a great amount of energy use, it is a significant improvement on a standard code based design. The yearly energy savings of over 7-million kWh, which at an average cost of 18-cents per kWh, is a cost savings $1.29-million per year, presents an excellent return on investment for the first cost of the energy efficiency measures.