Energy consumption of mixed-mode air conditioned cellular offices in São Paulo: considerations about the design

Abstract The literature presents only a limited number of studies on mixed-mode air-conditioned buildings (or with hybrid ventilation) with simple design strategies. Thus, this project evaluates the impact of architectural (room shape, window size and orientation) and usage parameters (equipment load density and air conditioning activation temperature) on the thermal performance of mixed-mode cellular offices in the city of São Paulo. The method consisted in characterising the studied models using a data survey of this building type and parametric computer simulations using the EnergyPlus software. The method demonstrated that hybrid ventilation led to a decrease of up to 52% in the energy consumption of the air conditioning used for cooling. When adopting such strategy, it is important to associate the room's shape to the window area. Lower energy consumption levels were observed for the combinations of deep and narrow rooms with larger windows or less deep and wider rooms with smaller windows. However, the decrease in the effective area for ventilation changed these conclusions, always yielding lower energy consumption with smaller windows. Hence, this study indicates that an adequate combination of parameters can result in designs that consume less energy, assisting in the design of this type of building.

摘要 现有文献中，针对采用简约设计策略的混合模式空调建筑（或搭载混合通风系统的建筑）的相关研究较为匮乏。为此，本项目针对圣保罗市的混合模式隔间式办公建筑，评估了建筑参数（房间形状、窗户尺寸与朝向）及使用参数（设备负荷密度、空调启动温度）对其热性能的影响。本研究方法包括通过针对该类建筑的调研对研究模型进行特性表征，并采用EnergyPlus软件开展参数化计算机仿真。仿真结果表明，混合通风策略可使制冷空调的能耗最高降低52%。采用该策略时，需将房间形状与窗户面积进行合理匹配。研究发现，进深较大且狭窄的房间搭配大尺寸窗户，或进深较小且宽敞的房间搭配小尺寸窗户的组合，均可实现更低的能耗水平。但当通风有效面积缩减时，上述结论会发生改变：此时采用小尺寸窗户始终可带来更低的能耗。综上，本研究表明，对各类参数进行合理组合可实现低能耗设计，可为该类建筑的设计提供参考依据。