Gitte T. Tranholm, Jannick Karsten Roth and Lennart Østergaard
Bibliographic info:
33rd AIVC Conference " Optimising Ventilative Cooling and Airtightness for [Nearly] Zero-Energy Buildings, IAQ and Comfort", Copenhagen, Denmark, 10-11 October 2012

The energy consumption needed for establishing a good indoor climate in shopping centres is often very high due to high internal heat loads from lighting and equipment and from a high people density at certain time intervals. This heat surplus result in a need for cooling during most of the year, typically also during the winter, and often the needed cooling is provided by a mechanical ventilation system with integrated mechanical cooling.

However, for certain areas, especially the hallways connecting the individual shops, natural ventilation might be an energy efficient alternative or supplement to the traditional mechanical system.

This paper presents a case study on an existing shopping centre in Copenhagen, Denmark (Fields shopping centre). The building owner’s key reason for considering natural ventilation was a desire to improve the thermal indoor climate in the hallways, and, at the same time, reduce the energy consumption for ventilation.

On this background, WindowMaster conducted a number of simulations in the dynamic simulation program BSim2002. These calculations suggested a significant energy saving potential (60% reduction) and a significant improved thermal indoor climate (70% reduction of annual hours above 28 °C) by adding natural ventilation to the ventilation strategy.

Thus, in the beginning of 2011 the building owner decided to install automatically controlled natural ventilation in the hallways in the shopping centre in addition to the existing mechanical ventilation system. The basic control idea was to use the natural ventilation system in the summer and transient seasons and the mechanical ventilation system in the winter (hybrid ventilation).

Measurements of the thermal indoor climate in the first year (September 2011 - August 2012) show that the indoor climate has improved significantly. In this year, the actual results outperform the expected results from the simulations, and the building owner has expressed his satisfaction with the improvements in the thermal indoor climate.