Even the most modern buildings can use far more energy than the designers intended. EU researchers have created an open source energy management system that can pinpoint where energy is being wasted and indicate possible solutions.
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Modern buildings are increasingly designed to be energy efficient, often employing sophisticated sensing and management systems to keep energy consumption under control. However, in too many cases, the envisaged savings are still not being achieved.
We have examples showing that many, many buildings do not operate as expected from their design, says Pascale Brassier, coordinator of the EU-funded HIT2GAP project. In some cases, this energy-performance gap means buildings are consuming more than twice the expected amount of energy.
There can be many reasons why buildings do not perform as well as intended. The design calculations could be erroneous, faulty techniques or wrong materials may have been used in construction, and the commissioning of the building services may not have been optimal. But many of the losses arise during the normal, everyday operation of the building and that is what HIT2GAPs 22 partners set out to address.
The projects solution is called BEMServer, an open source software package that acts as a gateway between the buildings own sensing systems and a set of optional modules that provide a range of energy-monitoring and optimisation services.
The BEMServer collects data such as indoor temperature and humidity, electricity consumption for lighting, heating and ventilation, data on the operation of the heating system and even external weather conditions. These measured data are the fuel for the BEMServer services, Brassier says.
Several of the modules offer simulations of the building calibrated against actual measurements. So you can have a real-time simulation tool that will help to detect malfunctioning of the system. It can help a facility manager identify the problem and intervene to correct it very quickly.
Buildings in four countries have been used as test beds for the BEMServer: a nanoscience research centre in San Sebastian, Spain, the town hall in the Wilanów district of Warsaw, Poland, the engineering building of the National University of Ireland in Galway, and the headquarters of Bouygues Construction near Versailles in France.
Brassier says the Galway example, in particular, showed how much could be saved by attending to failings in air-handling systems. The faults were detected in a very reliable and precise way. These are common faults which can be found in every building. When we corrected them we measured the impact and found a high potential for energy saving.
The project estimated that savings of between 25 % and 65 % could be made in electricity consumption of typical air-handling systems. This is a very good example of the positive impact generated by the BEMServer and the modules.
Another module detects omissions by the occupants, such as leaving lights on or windows open overnight, although Brassier admits that human behaviour is much harder to influence than adjusting machinery. This is a difficult topic but its a very big source of the energy-performance gap so this module and this service is very important.
HIT2GAP ended in August 2019 but the work is continuing. As the BEMServer is free and open source, anyone can develop it further or create and sell add-on modules to work with it. Twelve modules are available to date.
Brassiers company, Nobatek/Inef4, is working on new modules as well as improving the robustness of BEMServer itself by pre-processing the data received from the building management system to improve the quality of the data delivered to the modules.
We do not need closed, black-box systems, the coordinator stresses. We are trying to push in the other direction by providing an open source tool that people can use, modify and expand for their own needs.