Mitsubishi uses CFD for uniform airflow and room temperature14th April 2022
JAPAN: Mitsubishi Electric has developed a new airflow control technology that is said to achieve optimised room-wide comfort by both visualising and analysing air conditioning airflow and temperature distribution.
The technology predicts airflows and temperatures in a room to minimise uneven temperatures and discomfort due to excessively strong airflow. Mitsubishi Electric says it also expects to use its new solution to advise building owners and designers on how to enhance indoor layouts for increased comfort.
Indoor airflow has traditionally been controlled independently by each air conditioning unit using data from its built-in sensors. Mitsubishi argues that depending on the room layout and/or position of each unit, airflow may not reach areas such as corners. Also, the operation of adjacent units can disrupt intended airflows.
Mitsubishi Electric’s new technology generates 3D models using information on room and air-conditioning system layouts, and it also predicts airflow and temperature distribution using CFD analysis to test various conditions, including airflow angles/volumes and heat levels. From the CFD analysis results, the technology selects the most ideal conditions and controls the air conditioning system’s actual operation.
As a result, the technology enables airflow to be optimised, even when multiple AC units are operating in the same room. Airflow analysis enables the prediction of complex airflow and temperature distribution, which is used to determine ideal airflow volume and direction required to maximise room-wide comfort, including in spaces near the floor and behind obstacles. Collisions between diagonal airflows are avoided and conditioned air reaches all corners of the room relatively uniformly.
In areas by windows, where the floor temperature takes a long time to rise due to cold air from coming through the windows, the time required to close the temperature gap between 0.1m and 1.7m above the floor by at least 3°C was reduced to just 3 minutes, compared to 163 minutes conventionally. This was confirmed in tests conducted by Mitsubishi Electric at SUSTIE, its net zero energy building technology-demonstration facility in Kamakura, Japan.
The data required for airflow analysis, such as the locations of walls, floors, columns and A/C equipment, is extracted from BIM data to generate the 3D models. Airflow analysis is performed by virtually testing models incorporating different furniture, indoor units and ventilation system layouts to visualise airflow, temperature-distribution and ventilation effects. Room, indoor units and ventilation system layouts can be changed easily on-screen and the model numbers of specific Mitsubishi Electric AC systems can be entered from a database. Results of different patterns can be compared using airflow animations and colour-coded diagrams of temperature contours, CO2 concentration levels and times required for air from vents to reach specific areas.
Details of the new technology will be announced on April 21 at the 55th Japanese Joint Conference on Air Conditioning and Refrigeration, which will be held at the Etchujima Campus of Tokyo University of Marine Science and Technology on April 20-21.