INNOVAL
The hot climate at Le Port led the team in charge of the INNOVAL project to prepare a cooling strategy for different seasons. During the winter, natural ventilation is sufficient to cool offices and during the mid-season between the winter and the summer, natural ventilation is completed with ceiling fans. However, during the summer, natural ventilation coupled with ceiling fans are not sufficient, consequently, air conditioning has to be used. In buildings in Reunion Island, a significant percentage of the energy consumed is due to air conditioning, therefore, the air conditioning system selected here is an efficient one with a Variable Refrigerant Flow ensuring reliability and energy savings. Moreover, a software tool automatically regulates the power of cooling in relation to office use. Finally, while in Reunion Island, people are used to cooling below 24 °C, the air conditioning of the building cannot cool below 26 °C which is adequate with ceiling fans and natural ventilation. Indeed, with the assistance of ceiling fans, the felt temperature is reduced by 5 °C allowing a final felt temperature of 21 to 22 °C. In order to optimize the refrigerated unit power, the temperature adjustment consists of applying a difference of 5 °C between the outside and the inside. For example, if the outside temperature is 34 °C, the temperature adjustment will be 29 °C. All these choices in operation have led to a decrease from 100 kW to 30 kW in the power required by the refrigerated unit.
Bank of America Tower (Manhattan)
Temperature control and the production of some of its energy are accomplished in an environmentally friendly manner for the tower. Insulated glazing reduces thermal loss, lowering energy consumption and increasing transparency. Carbon dioxide sensors signal increased fresh air ventilation when elevated levels of carbon dioxide are detected in the building. Conditioned air for the occupants is provided by multiple air column units located in the tenant space that deliver 50 °F air into a raised access floor plenum. This underfloor air system provides users with the ability to control their own space temperature as well as improving the ventilation effectiveness. When building churn occurs, workstation moves can be performed more easily with lower cost and less product waste. The cooling system produces and stores ice during off-peak hours, and allows the ice to melt to help cool the building during peak load, similar to the ice batteries in the 1995 Hotel New Otani Tokyo in Japan. Ice batteries have been used since absorption chillers first made ice commercially available 150 years ago, before the invention of the electric light bulb.