Mass transfer in buildings
The phrase ‘mass transfer’ describes the net movement of mass from one place to another in liquids and gases.
In the simplest interpretation, mass transfer refers to the movement of mass by diffusion at a molecular level. Mass will diffuse from areas of high concentration to areas of low concentration, as described by Fick's law. In this interpretation, the movement of mass by fluid motion (such as convection) is more correctly a part of fluid dynamics rather than mass transfer. That is, mass transfer is dependent on a concentration gradient whereas fluid motion is dependent on a temperature or pressure gradient.
The evaporation of water is an example of simple mass transfer, as the humidity of the air close to the surface of water is higher than that in the surrounding air and so moisture vapour diffuses away from the surface of the water, allowing more water to evaporate.
However, mass transfer is also sometimes taken to refer to fluid flows, driven by temperature and pressure gradients and to phase change.
Mass transfer in buildings is particularly important in cooling processes, such as in cooling towers, chiller units, heat pumps and so on.
Mass transfer is sometimes considered alongside heat transfer, as they are very similar and related processes.
[edit] Related articles on Designing Buildings
Featured articles and news
C20 Society; Buildings at Risk List 2025
10 more buildings published with updates on the past decade of buildings featured.
Boiler Upgrade Scheme and certifications consultation
Summary of government consultation, closing 11 June 2025.
Deputy editor of AT, Tim Fraser, discusses the newly formed society with its current chair, Chris Halligan MCIAT.
Barratt Lo-E passivhaus standard homes planned enmasse
With an initial 728 Lo-E homes across two sites and many more planned for the future.
Government urged to uphold Warm Homes commitment
ECA and industry bodies write to Government concerning its 13.2 billion Warm Homes manifesto commitment.
From project managers to rising stars, sustainability pioneers and more.
Places of Worship in Britain and Ireland, 1929-1990. Book review.
The emancipation of women in art.
Call for independent National Grenfell oversight mechanism
MHCLG share findings of Building Safety Inquiry in letter to Secretary of State and Minister for Building Safety.
The Architectural Technology Awards
AT Awards now open for this the sixth decade of CIAT.
50th Golden anniversary ECA Edmundson awards
Deadline for submissions Friday 30 May 2025.
The benefits of precast, off-site foundation systems
Top ten benefits of this notable innovation.
Encouraging individuals to take action saving water at home, work, and in their communities.
Takes a community to support mental health and wellbeing
The why of becoming a Mental Health Instructor explained.
Mental health awareness week 13-18 May
The theme is communities, they can provide a sense of belonging, safety, support in hard times, and a sense purpose.
Mental health support on the rise but workers still struggling
CIOB Understanding Mental Health in the Built Environment 2025 shows.
Design and construction material libraries
Material, sample, product or detail libraries a key component of any architectural design practice.