An evaluation of the thermal performance and energy efficiency of atria in hotel buildings in the UK: A case study of the Orchard Hotel, Nottingham

Hotels are one of the most energy intensive sectors of the tourism industry. Research indicates that hotels consume more than half of their overall energy consumption for space conditioning alone. The building fabric has a major influence on hotels space conditioning needs. Atria, which are popular in hotel designs for their aesthetic value, can act as a thermal barrier between the exterior and interior spaces, therefore potentially contributing to a reduction in the space conditioning needs of a building. Despite this theoretical advantage, the body of available literature discussing the performance of atria in hotels is limited. In this work, the authors contributed to this knowledge gap through evaluating the performance of an atrium in a hotel based in Nottingham, UK. In situ temperature monitoring and dynamic building simulations were used. The atrium was initially assumed in a free running mode to test the thermal performance of the building envelope alone, and numerous cases were developed where parameters such as building orientation, fenestration characteristics, openings for ventilation and skylight properties were varied. Integrated Environmental Solutions Virtual Environment software was used to generate thermal comfort evaluations and to assess summer overheating risk. The simulation findings suggested that the skylight glazing ratio was the most important characteristic that influenced the indoor thermal condition which, combined with natural ventilation, significantly contributed to the overall hotels’ energy usage. Based on the initial assessment, the existing atrium configuration in a free running mode would provide only 41% of comfort hours, and be at a risk of overheating for 8.7% of the summer. A substantial improvement in the thermal performance with 83% of comfort hours achieved in the summer and 0% risk of summer overheating was demonstrated through a combination of the proposed passive strategies along with natural ventilation in summer months. The best optimised case also presented an 88% reduction of summer cooling loads and 18% reduction of winter heating loads when active systems were assumed. Therefore, the authors concluded that there was significant room for the optimisation of the design of atria as contributors to comfort and energy efficiency in hotels in temperate climate zones.