True Energy Solutions (TES) were appointed to provide whole building energy modelling, daylight simulation and life cycle cost analysis for the BREEAM certification of the A energy class Saltoniskiu 7 (S7) business centre in Vilnius, Lithuania. The building is the first project to achieve a BREEAM Excellent rating in Lithuania, and only the second in the Baltic region.
All of the low and zero carbon technologies for the building were assessed by TES in IESVE. This included full energy modelling for the Energy 1 credit, to determine the energy efficiency of the design building and how the systems will operate. The building design incorporated a district heating system with heat pump, therefore one particular challenge was selecting the most appropriate capacity for the heat pump in order to deliver the highest economic value to the client. With the help of IESVE, TES were able to see the annual energy demand and determine to what extent the heat pump could cover it.
During the early design stages, the client was also interested to know the predicted energy costs in order to assist negotiations with prospective future tenants. Even in the early stages, TES were able to provide a prediction of energy consumption, on a floor by floor basis and with different configurations of the space, using the functions within IESVE.
The SunCast application allowed TES to assess the solar exposure on the building windows and façade to determine where external blinds could be placed in order to reduce cooling loads. This analysis enabled TES to demonstrate what effect could be achieved with the external blinds and helped the client make an informed decision on whether to include them in the final design, which they ultimately did.
Daylight modelling, performed in RadianceIES, was also used to assess daylight factors and establish the uniformity of daylight distribution. While shading was relatively deep in some spaces, the height of the windows allowed for good levels of daylight distribution throughout the internal spaces. This meant that the client could demonstrate to future tenants that most spaces within the building would have good levels of daylight available.
The building also incorporates an internal courtyard, so the client was keen to understand how this space would look depending on different sky conditions. While other modelling tools would allow TES to give some visualisation, many rendering software packages are designed to make the building appear prettier, and do not represent how the space will look in real life. A major benefit for TES of using RadianceIES, therefore, was that they were able to predict how the courtyard would look under various sky conditions, based on actual physics, and could give better predictions of how the space would appear in reality.
Finally, TES were able to export all of the materials assigned to the model into One Click LCA to perform the lifecycle assessment. This proved to be a huge time saver for TES as all of the thermal constructions were already available in the IESVE model, reducing the time spent on recalculating inputs.
“Out of all the energy modelling software I have experienced, I believe that IESVE has the best user interface. It’s easy to understand, there are a lot of applications that help run all the studies. The user friendliness is one of the strongest sides of IES.
"We are now involved with the second building in this development, which is under construction right now, and we plan to use even more features of IESVE - we’re going to run comfort studies and CFD modelling. So, the second project will be even more broadly covered by IESVE than the first one was. The first building was the first phase so for the second one we are aiming even higher.”
- Kiril Simbirskij, Head of Buildings Department, TES