Government Building Refurbishment


IESVE used to model a pilot project for a government building refurbishment in Slovakia.

Key Facts

  • 3 separate designs modelled in the IESVE – original, current and proposed
  • Proposed design aimed to achieve 60% primary energy savings
  • Discovered possible to generate 21 360 kWh per annum of electricity with PV panels which pushed the energy savings beyond the desired 60%

SALVIS was appointed by a non-government organization ENBEE (working on European Energy Efficiency certificate ALDREN – international building energy efficiency evaluation tool) to carry out an energy simulation of a government building refurbishment. The main task was to simulate three separate designs of the building in question using an appropriate energy simulation tool: 1) original state right after building completion (year 1999); 2) current state (year 2019); 3) proposed state. Using appropriate ECMs 60% energy savings on primary energy had to be achieved.

Energy modeling experts at SALVIS have been  working with IESVE for the past nine years. They found that the IESVE’s capabilities and setting options perfectly met the needs of such tasks as  it was not only necessary to model and set constructions, heating, and cooling sources in detail but the controls of the HVAC systems as well. The SALVIS team found that the IESVE modeling software proved to be very suitable and versatile in this regard.

Before any work could be started on the 3D model, all relevant and available information had to be collected about the building, it’s operation, occupancy, space usage and HVAC systems. A site inspection was done by accredited professionals in building thermal protection and HVAC and interior lighting, who evaluated the current state of the building based on inspection and available documentation, the original state based on original documentation, and they prepared proposed ECMs to enable an estimated achievement of 60% primary energy savings and cost feasibility.

Eventually the energy simulations were carried out in all three state scenarios and the results were compared to measured data from previous years (current state) and the 3D model and settings were adjusted accordingly. 

Among the first steps to improve energy efficiency was the addition of thermal insulation on external walls (where it was technically possible), original double-glazed windowpanes were exchanged for triple glazing low-e panes and external shading blinds were installed where appropriate. Several energy efficient HVAC systems were simulated and evaluated, and aVRV system for space heating and cooling proved to be the most feasible HVAC system for refurbishment. Mechanical ventilation with a highly efficient energy recovery was also simulated,  along with DCV based on room CO2 concentration, local electric instantaneous boilers for DHW and highly efficient LED interior lighting fixtures with automatic dimming control based on daylight availability within regularly occupied spaces.

To achieve the 60% of primary energy savings against current state energy consumption the PV array had to be considered and simulated with electricity yield of approx. 20 000 kWh per annum. The IESVE was used for electricity generation calculations since it has the capabilities of detailed PV settings. With 135 m2 south oriented roof area and 20° and 45° roof slope it was discovered possible to generate 21 360 kWh per annum of electricity with PV panels which pushed the energy savings beyond the desired 60%.

SALVIS company is grateful to have been part of the European building energy evaluation tool by participating in a pilot. The team found that the IESVE proved to be the right tool for this challenging task.

Martin Kosiciar, Building Energy Simulations, Salvis