Editing Heat recovery ventilation (section)

=== Phase change materials ===
[[Phase-change material|Phase change materials]], or PCMs, are a technology that is used to store sensible and latent heat within a building structure at a higher storage capacity than standard building materials. PCMs have been studied extensively due to their ability to store heat and transfer heating and cooling demands from conventional peak times to off-peak times.

The concept of the thermal mass of a building for heat storage, that the physical structure of the building absorbs heat to help cool the air, has long been understood and investigated. A study of PCMs in comparison to traditional building materials has shown that the thermal storage capacity of PCMs is twelve times higher than standard building materials over the same temperature range.<ref>{{Cite journal|last1=Feldman|first1=D.|last2=Banu|first2=D.|last3=Hawes|first3=D.W.|date=February 1995|title=Development and application of organic phase change mixtures in thermal storage gypsum wallboard|journal=Solar Energy Materials and Solar Cells|volume=36|issue=2|pages=147–157|doi=10.1016/0927-0248(94)00168-r|issn=0927-0248}}</ref> The pressure drop across PCMs has not been investigated to be able to comment on the effect that the material may have on air streams. However, as the PCM can be incorporated directly into the building structure, this would not affect the flow in the same way other heat exchanger technologies do, it can be suggested that there is no pressure loss created by the inclusion of PCMs in the building fabric.<ref name=":2">{{Cite journal|last1=O’Connor|first1=Dominic|last2=Calautit|first2=John Kaiser S.|last3=Hughes|first3=Ben Richard|date=February 2016|title=A review of heat recovery technology for passive ventilation applications|journal=Renewable and Sustainable Energy Reviews|volume=54|pages=1481–1493|doi=10.1016/j.rser.2015.10.039|issn=1364-0321|url=http://eprints.whiterose.ac.uk/104584/1/Manuscript%20-%20Revised%20Final.pdf}}</ref>