Energy-Dependent Cooling, the Electrical Grid, and Passive Cooling of Environments and Structures – Some Considerations

John A Dougherty, Jr. May 20, 2024

Electrification of our home, work, and transportation environments is proceeding at a rapid pace and promises to reduce the amount of carbon dioxide released into the atmosphere when energy is from renewable sources such as wind, hydro, solar, and ocean energy, and geothermal.  However, recent reports of long delays around the country in the ability of the electrical grid to accept new renewable sources of energy raise questions about the ability of the grid to support all of the proposed electrifications.  Efforts to expand the capacity of the electrical grid come with additional costs that will make electricity even more expensive than it is now, and the existing grid is vulnerable to weather events, earthquakes, and has been implicated in the initiation of multiple wildfires, especially during ‘heat dome’ excessive heat events.

During heat events electricity providers may stop transmitting power to prevent wildfires or may not be able to keep up with the demand for power, leaving residents without electricity to cool their dwellings with air conditioners when cooling is most needed for health and well being, especially among low-income and older adults.

While there are many good reasons for increased use of electrical means for cooling, passive cooling approaches may be needed to keep our dwellings and workplaces at healthy temperatures, 

For example, I currently live in a multifamily apartment building, built in the 1970s, and with such poorly insulated outside walls that the heat flux from direct sunlight readily penetrates into my apartment.  The amount of energy that I must use to air condition my apartment in the summer months is significantly increased because of the additional heat penetrating my apartment from solar radiation and to a smaller extent from hot air temperatures.  The large apple tree that used to block the sun from shining on my apartment walls for most of the morning has now been cut down, further increasing the amount of heat that enters my apartment that must then be processed by my portable heat pump by using more energy.  I must use more and more energy to keep indoor temperatures at healthy levels as sun-blocking and transpiration-cooling foliage is cut down. 

Passive cooling techniques that do not require electricity but block direct solar radiation and in some cases cool by transpiration have increasingly been used around the globe for keeping home and work environments at livable temperatures.  Below are links to articles about passive cooling dissipation techniques for buildings, how the Colombian city of Medellin used green foliage to drive down ambient and indoor temperatures, how cooling paint can drop the temperature of any surface even in direct sunlight, and how newly designed buildings can use passive cooling methods – developed by examining termite mounds and other biological cooling processes – can significantly reduce indoor temperatures and reduce the amount of electricity used for cooling.

• https://www.sciencedirect.com/science/article/abs/pii/S0378778812005762  [Passive cooling dissipation techniques for buildings and other structures: The state of the art]
• https://reasonstobecheerful.world/green-corridors-medellin-colombia-urban-heat/
• https://www.science.org/content/article/cooling-paint-drops-temperature-any-surface
• https://grist.org/fix/energy/these-self-cooled-buildings-were-inspired-by-termites-and-frogs/

Of course, providing retrofits to existing structures in the form of additional insulation, window awnings, and reflective surfaces, and the addition of deciduous trees that are resistant to wind and storms, and adapted to our changing climate, would be excellent ways to provide passive cooling and neighborhoods and in work spaces in summer months – as in Medellin. 

Flexible strategies that utilize both passive and energy-dependent cooling tailored to the needs of each situation are likely to be the most successful in providing healthy indoor and outdoor temperatures while minimizing the costs of cooling and the burden on the electrical grid.  Keeping costs low is especially important for low-income families, older and disabled persons, and families renting in multi-unit dwellings, who often are more affected by rising temperatures than higher income and able bodied families.