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
Twas the site before Christmas...
A rhyme for the industry and a thankyou to our supporters.
Plumbing and heating systems in schools
New apprentice pay rates coming into effect in the new year
Addressing the impact of recent national minimum wage changes.
EBSSA support for the new industry competence structure
The Engineering and Building Services Skills Authority, in working group 2.
Notes from BSRIA Sustainable Futures briefing
From carbon down to the all important customer: Redefining Retrofit for Net Zero Living.
Principal Designer: A New Opportunity for Architects
ACA launches a Principal Designer Register for architects.
A new government plan for housing and nature recovery
Exploring a new housing and infrastructure nature recovery framework.
Leveraging technology to enhance prospects for students
A case study on the significance of the Autodesk Revit certification.
Fundamental Review of Building Regulations Guidance
Announced during commons debate on the Grenfell Inquiry Phase 2 report.
CIAT responds to the updated National Planning Policy Framework
With key changes in the revised NPPF outlined.
Councils and communities highlighted for delivery of common-sense housing in planning overhaul
As government follows up with mandatory housing targets.
CIOB photographic competition final images revealed
Art of Building produces stunning images for another year.
HSE prosecutes company for putting workers at risk
Roofing company fined and its director sentenced.
Strategic restructure to transform industry competence
EBSSA becomes part of a new industry competence structure.
Major overhaul of planning committees proposed by government
Planning decisions set to be fast-tracked to tackle the housing crisis.
Industry Competence Steering Group restructure
ICSG transitions to the Industry Competence Committee (ICC) under the Building Safety Regulator (BSR).
Principal Contractor Competency Certification Scheme
CIOB PCCCS competence framework for Principal Contractors.
The CIAT Principal Designer register
Issues explained via a series of FAQs.