Human activities are changing the planet’s climate including its natural greenhouse. Over the last century the processing of fossil fuels in particular has raised concentration of atmospheric carbon dioxide and this has led to what was once generally called ‘global warming’.
The last five years (2015-2019) saw the hottest average temperatures ever recorded at a global scale, including more frequent, longer and hotter heatwaves on every inhabited continent. An assoicated concern is that occasional record high temperatures cause sharp rises in heat-related deaths as the climate warms.
These days climatologists prefer to term ‘global heating’. This is defined by Prof Richard Betts, who leads the climate research arm of Britain’s meteorological monitoring organisation, interviewed by The Guardian, as: “Global heating is technically more correct because we are talking about changes in the energy balance of the planet.”
To address global heating and the impact on how we live our lives indoors, an array of different scientific deveopments are underway. We take in three examples.
Keeping cool – with seawater
One consequence of a growing global population is that the global air-conditioning demand will continue to rise. How can cooling be maintained in a sustainable way? A new study looks at the possibility of using seawater air-conditioning as an alternative cooling solution.
In terms of how this might work, seawater air-conditioning requires the pumping of seawater from ocean depths of around 700 to 1200 meters and temperatures of 3°C to 5°C to the coast. Here the cooler water exchanges heat with a local cooling system. The warmer water is then passed back into the sea.
While the relative efficiency of the technology has been demonstrated on a small scale, scientists are cautious in terms of avoiding environmental damage, especially in relation to coastal erosion.
The seawater solution is outlined in the journal Energy Efficiency, with the research paper titled “High velocity seawater air-conditioning with thermal energy storage and its operation with intermittent renewable energies.”
Pigments for use in “Cool” Coatings
A different development involves the design of different pigment, designed to counteract the effects of warm external temperatures in terms of peoplewho work indoors.
A new project has been set up to develop and test several novel pigments. These are pigments that exhibit high near infrared-reflectance. In doing so, the pigments have a potential for creating so-termed “cool” coatings. A “cool” coating is a material that will reflect more solar radiation compared with standard coatings. The outcome is that a building coated with the material would require less energy in order to keep cool.
In terms of colors, blue and black pigments show the most promise to produce “cool” coatings. In trials, black pigments have been added to epoxy coating.
Overall, higher magnesium content, and especially, higher aluminum content, improves solar reflectance. The addition of iron to a pigment also imparts the required properties.
Cool and green roofs
Roofs are an aspect of all buildings where advanced solutions can be deployed to provide significant energy savings. This is achived by selecting appropriate cool materials that can keep the roof cool under the sun. Optimal materials will reflect the incident solar radiation away from the building and radiating the heat away at night.
One research strand has discovered that roofs covered with vegetation take provide additional thermal insulation, which is a factor of the soil. in addition, the right type of vegetation creates conditions of evapo-transpiration which also helps to keep the roof cool under the Sun.
A new research paper looks at the optimal ‘green roof’ solutions based on numerical analysis, outlining how cool and green roofs can improve the energy performance of residential buildings. The paper is presented in the journal Energy and Buildings and it is titled “Cool and green roofs. An energy and comfort comparison between passive cooling and mitigation urban heat island techniques for residential buildings in the Mediterranean region.”
Essential Science
This article is the latest in Digital Journal’s Essential Science series. Each week we consider a topic of interest relating to each of the core fields in science, presenting an important subject in the form of a digestible read.
Last week, we took in how body of evidence in favour of face masks continues to grow and we considered a diverse array of different literature that looks at mask wearing in different contexts.
The week before the topic was hurricanes, with predictions indicating that this year’s hurricane season is expected to see more storms than is typical together with storms of greater intensity. It appears that climate change is the reason for this.
