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Energy simulation and assessment of the energy standard of buildings


The current legislative requirements in the building industry, the technology used in it, and the ever-increasing prices of energy carriers require more and more precise methods of determining ordered power and energy requirements for existing and planned buildings. Commonly used simple calculation methods often do not allow for a precise definition of the demand for heat or the amount of energy that will be consumed in the future by a projected or upgraded building. Increasingly, computer systems of simulation are used to precisely determine these quantities.

Computer energy demand simulation for buildings enables engineers, architects and researchers to model time-varying energy requirements for heating, cooling, ventilation and lighting of existing and planned buildings. Computer simulation systems also allow for the modeling of the demand for energy carriers and the water supplied to the facility. Modeling of variables during building performance allows people involved in the design of a new building or upgrading an existing building to make decisions that optimize architectural and installation solutions, leading to reduced energy and water requirements for the building being designed.


  • Demonstration of energy demand for heating and cooling for residential and public buildings with any time step and for any time span at any design stage
  • Determining the energy demand for energy supply systems in a building based on the demand for utility energy
  • Modeling of cogeneration systems and polygeneration of energy, allowing to determine the efficiency of the application of such solutions in the construction industry
  • Calculations using computer dynamics (CFD) methods for modeling the speed and air velocity fields in the rooms of the designed buildings and in its surroundings
  • Analyzing daily and artificial lighting in the designed buildings
  • Determining the electricity demand for the lighting and operation of indoor equipment in buildings
  • Energy analyzes of various architectural solutions in construction - double facades, external shading
  • Advising on technical solutions with an impact on energy consumption in existing and planned buildings - modern systems of natural ventilation, hybrid and solar-assisted, non-standard solutions in the field of strategy and control systems for heating and cooling and ventilation of buildings
  • Energy simulations performed for the needs of energy performance assessment systems of buildings
  • Calculations using energy modeling methods, which allow to determine the conformity of a building design with the requirements of the presently-built objects
  • Analysis of pollution and indoor air quality in buildings


All calculations and energy analyzes of buildings and their energy supply systems are made using specialized software for energy simulations. For simulation calculations, EnergyPlus, ESP-r and calculation programs and procedures developed by experts and professionals working with the National Energy Conservation Agency are used. In order to increase the efficiency of the EnergyPlus energy simulation system, the DesignBuilder version of the Advanced Simulation Package and the OpenStudio Plugin for Google SketchUp are used to prepare the building model and analyze the calculation results. Both systems support the use of the EnergyPlus calculation engine, which has the following features:

  • Integrated energy simulations of the building and its internal installations - conjugate energy demand calculations and energy supply systems work
  • Hourly, user-defined, calculation step used in the calculation of the thermal dynamics of building zones, their interactions with the external environment and internal building systems.
  • Time-varying heat conduction streams in individual building elements using the thermal response function
  • Improved calculation of heat loss of a building to ground using three-dimensional modeling using finite difference methods and simplified analytical methods.
  • Composite modeling of heat and mass transfer in building partitions using the response function or the effective moisture penetration model (EPDM)
  • Modeling of thermal comfort in building premises on the basis of declared physical activity of persons
  • Anisotropic model of the sky used to calculate the intensity of diffuse radiation on the exterior surface of the building
  • Advanced models of transparent partitions, using controlled shading elements, electrochromic shafts, etc.
  • Daylight illumination analysis, illumination calculations, glare simulations and countermeasures, artificial lighting limitation
  • Modification of the design loop for heating, cooling and ventilation systems
  • Internal air quality analysis to reduce the energy demand of the building

Additionally, Design Builder allows to perform:

  • architectural analyzes and related energy simulations of individual solutions
  • operational analysis of buildings
  • calculation of thermal comfort and air velocity fields using CFD techniques
  • calculations for the needs of energy certificates and technical requirements of buildings

Energy analyzes and simulations of buildings can also be performed using algorithms in accordance with Polish and European standards. For this purpose, computational algorithms based on norms and computational libraries have been developed. The STEP ESS 2.0 computational energy library is a programming tool developed for the development of software for energy analysis in the building industry. Especially useful is the construction and development of software used to determine energy demand for heating and cooling of buildings for energy analysis and auditing of buildings and software used in the energy efficiency assessment of residential and public buildings. The Energy Simulation System (ESS) was developed under the STEP - Sustainable Thermomodernization of Public Buildings project. The ESS library uses two methods for determining energy demand for heating and cooling of buildings, developed in the STEP project. The first is an hourly method based on the mathematical model 6R1C of the building's thermal dynamics, while the second is a pseudodynamic balance method with a monthly computational period. The structure of the construction of computational kernel library STEP ESS 2.0 can be a central part of graphic simulation of building energy applications working in Windows ™.

The scope of energy simulation is adapted to the complexity of the projected or upgraded building and the type of technology that can be used. An additional parameter influencing the complexity of the applied model used in simulation and energy analyzes is the availability of input data. Energy simulations are also adapted to the design stage. Simplified energy analyzes are used in the early stages of building design, while complex energy analyzes are performed at the final stage or on an as-built basis.


Office building Tulipan House in Warsaw, the National Fund, the Ministry of Environment, Sheraton Hotel Warsaw, Main Building of the Center for Children's Health, Energy balance for the Temple of Divine Providence, SEGECE: the development of the Sadyba Best Mall, Krakow Plaza, Lublin Plaza, Poznan Plaza, Ruda Slaska Plaza, Rybnik Plaza, Sosnowiec Plaza

Persons responsible for contact with customers

Andrzej Wiszniewski, awiszniewski@nape.pl, tel. 22 505-46-43
Jerzy Kwiatkowski, jkwiatkowski@nape.pl, tel. 22 505-47-41