HVAC Library

The XRGLibrary for modelling Heating and Cooling Systems in Buildings


State-of-the-art HVAC ("Heating, Ventilation and Air Conditioning") systems have to become more and more efficient to fulfil the requirements of their owners.

The XRG HVAC Library and HumanComfort Library offer a very flexible and powerful tool to analyze different system layouts and compare their primary energy consumption, their carbon dioxide emission or the energy costs with regard to any reference period (usually one year of operation). Scenarios like a cost optimized system layout with various heating and cooling generation devices can be analyzed within only few minutes. Different concepts of heat recoverage or humidity control can be modeled, simulated and analyzed in a few steps. By using transient models of the HVAC and HumanComfort Library even the thermal behavior of buildings and its interaction with the heating and cooling system are considered in the best way.

Heating System and Building Model

The animation above displays the transient operation of a conventional heating system for a single family house and integrated domestic hot water preparation. The models provided by HVAC Library were connected using a thermal heat connector compatible with that of the HumanComfort Library. Thus, a transient system consisting of climate conditions, building walls and windows, internal heat loads, heating system and the governing control is modelled in a modular way.

The animated figure shows one week of operation during a cold winter week. While the domestic hot water storage tank is heated to 60 degC once a day the radiators of the heating system are not provided with hot water. The figure reveals that the room temperature displayed by a red point leaves the gray-coloured comfort area during the charge of the storage tank.

Content of the XRG HVAC Library

  • Air ducting units with various cross sections
  • Adiabatic and steam humidifiers and water extractors
  • Borehole heat exchanger
  • Absorption- and vapor compression chillers
  • Evaporative and dry cooling towers
  • Boilers and combined heat and power
  • Heat pumps
  • Heat exchangers (liquid and air side)
  • Radiators and floor heating (compatible with HumanComfort)
  • Heating and cooling consumers
  • Solar panels
  • Domestic hot water storages, ice storages and tanks
  • Pipes, valves and manifolds
  • Pumps, blowers and fans
  • Controllers
  • Automatic energy, emission and cost balances
  • Different fluid models for heating and cooling systems


The unique concept of our HVAC Library enables the user to carry out whole-year simulations in the shortest possible time (few minutes). Hence, systematic optimizations, e.g. by using our model optimization tool ModelOpt, are becoming possible.

Available for:

  • 3DS Dymola
  • OpenModelica
  • Modelon Impact