HVAC (Heating Ventilation and Air Conditioning) system-related noise and vibrations can unacceptably affect the acoustical environment in the space they serve.

Background noise in office building can lead to a significant decrease of the concentration and performances. High noise levels in factories are a significant cause of concern for HES (Environment, Health and Safety) management. Undesired noise coming from HVAC systems can cause lowering of concentration (libraries, schools), disturbance during rest (hospitals, clinics, hotels, residences, and apartments), and negatively influence activities that need a quiet background environment (churches, mosques, synagogues, performing art spaces, museums, recording studios and laboratories).

The importance of a correct acoustic design, which avoids the occurrence of undesired noise levels in occupied spaces, it is widely documented in scientific/technical literature. The construction of any new HVAC system should take into account a correct and accurate acoustic design. Furthermore, maximum noise levels prescribed by environmental regulations are becoming increasingly stringent. This results in an increased need of modification and correction of existing HVAC systems that exceed maximum noise levels.

The Graphical User Interface (GUI) of havcPRO allows for easy and intuitive visual modelling of HVAC networks, composed by a combination of different HVAC elements (fans, ducts, elbows, junctions, silencers, …) and building elements (rooms, walls, ceiling, openings, …). Complex HVAC systems can be easily modelled by drag&drop the elements from the Block Library to the Design Window. The acoustic properties of each element can be then defined in the Property Editor of the element.

Library of acoustic data for common HVAC network elements are included in the data library of hvacPRO. These acoustic properties, available for the most typical sound elements, are taken from the most up-to-date ASHRAE Handbooks. These libraries are continuously updated with the most recent data available in the scientific and technical literature.

The acoustic solver of hvacPRO has been designed following the most up-to-date theories and practices on HVAC acoustic design. The main theoretical fundaments of the software are based on the most up-to-date ASHRAE guidelines for the acoustic design of HVAC networks. The solver is continuously updated in order to comply with the more recent scientific and technical advances on acoustic design of HVAC networks.

Evaluation of different sound ratings (NC, NCB, RC, RC-MarkII, NR, RNC, DRC, dbA, etc.) allows for easy assessment of system compliance with noise regulations. Outputs of the acoustic solver, together with relevant sound ratings are displayed in the Results menu of the Graphical User Interface (GUI). These results can be also exported as data files.

The high degree of customization of hvacPRO allows the user to be able to solve accurately each HVAC network, even comprising non-standard elements. Customization of elements allows the user to introduce manufacturer’s acoustic data of elements not present in the data library.

As the propagation of sound in HVAC networks can take different paths, hvacPRO is designed to take into account those different paths. This results in a high degree of accuracy of the acoustic predictions. The main sound paths that hvacPRO is able to accurately solve are: discharge sound propagation, inlet sound propagation, breakout noise, unit-radiated sound. Besides the high accuracy, the computational time is low, thanks to the optimization of the acoustic solver.

The sound break-in through different HVAC elements can be taken into account by the solver of hvacPRO 2.0. This increases the accuracy of the simulations in low-noise buildings and applications.

The user can specify rooms of complex geometry by defining the shape of the parts. This allows the use of non-rectangular plants. The plant of the rooms can be a polygon of any shape with any number of edges and vertices.