International News
MODELLING ENERGY DEMAND
FOR FUTURE COMMERCIAL DEVELOPMENTS
MDPI , Based in Basel , Switzerland , that has the mission to foster open scientific exchange in all forms , across all disciplines , has recently published World 2020 – a Journal on required models to meet future energy demands in the built environment based on a case study in the US .
The building sector accounts for nearly 40 % of total primary energy consumption in the US and EU , and 20 % of worldwide delivered energy consumption .
Climate projections predict an increase of average annual temperatures between 1.1 – 5.4 ° C by 2100 . As urbanisation is expected to continue increasing at a rapid pace , the energy consumption of buildings is likely to play a pivotal role in the overall energy budget .
In this study , scientists used EnergyPlus building energy models to estimate the future energy demands of commercial buildings in Salt Lake County , Utah , US , using locally-derived climate projections .
They found significant variability in the energy demand profiles when simulating the study buildings under different climate scenarios , based on the energy standard the building was designed to meet , with reductions ranging from 10 % to 60 % in natural gas consumption for heating and increases ranging from 10 % to 30 % in electricity consumption for cooling .
A case study , using projected 2040 building stock , showed a weighted average decrease in heating energy of 25 % and an increase of 15 % in cooling energy . They also found that building standards between ASHRAE 90.1-2004 and 90.1-2016 play a comparatively smaller role than variation in climate scenarios on the energy demand variability within building types .
Their findings underscore the large range of potential future building energy consumption which depends on climatic conditions , as well as building types and standards .
MOTIVATION OF THE STUDY By 2050 , 66 % of the world ’ s population , and 82 % of North America ’ s population , are predicted to be living in urban environments , increasing the amount of energy consumed by buildings in cities .
Nevertheless , the relative impact of building energy consumption as a percentage of total delivery energy worldwide is projected by the US Energy Information Administration to be constant between 2012 and 2040 , as shown in Figure 1 .
These consumption scenarios primarily focus on economic growth for predicting future building energy consumption , but the report acknowledges the importance of energy-related components of climate pledges in advance of the 2015 Paris Climate Change Conference ( COP21 ).
However , according to a National Oceanic and Atmospheric Administration ( NOAA ) report , world average temperature is projected
Figure 1 : World energy consumption predictions , sector by sector .
to increase . De Wilde and Coley describe the link between climate and buildings : “ Buildings provide an interface between the outdoor environment , which is subject to climate change , and the indoor environment , which needs to be maintained within a range that keeps the occupants safe and comfortable , and which is suitable for any key processes that are taking places within the building ”.
An increase in air temperature will have a significant impact on building energy consumption worldwide , increasing the cooling energy demand and reducing the heating energy demand .
SIGNIFICANCE OF THIS WORK This study builds on and adds to the previous work :
• We used localised weather data specific to an urban area ( Salt Lake County ), developed by a team of atmospheric scientists , accounting for site-specific future projections as input for building energy simulations instead of average climate trends modelled for the whole country or the world .
• We used multiple building stock models , representing five commercial building types , in order to understand how a given variation in dry bulb temperature affects different building types . This study includes the five commercial building types most prevalent in the study area ( large office , small office , primary school , full-service restaurant , and highrise multi-family apartment buildings ) collectively comprising 49 % and 55 % of the floor area of existing and projected future building stock , respectively .
• We included multiple building energy standards ( ASHRAE 90.1-2004 , 2007 , 2010 , 2013 and 2016 ) to understand how a given variation in dry bulb temperature affects a given building type when built to meet different design standards .
• We considered the projected 2040 composition of Salt Lake County ’ s building stock to have a more realistic prediction of aggregated commercial building energy consumption . The full study can be downloaded free of charge from the MDPI website – World 2020 . RACA
www . hvacronline . co . za RACA Journal I November 2020 7