Thermal energy storage (TES) helps reduce the urban heat island (UHI) effect by capturing and storing excess heat absorbed by urban surfaces during the day, thus lowering the temperature of these surfaces and the surrounding air. This process mitigates the accumulation of heat in cities, which typically have extensive areas of concrete and asphalt that absorb and retain heat, contributing to higher urban temperatures compared to rural areas.
How Thermal Energy Storage Contributes to UHI Mitigation:
- Harvesting Excess Solar Heat: Urban surfaces such as buildings, roads, and sidewalks can reach temperatures as high as 50 °C. By installing flat absorber lines on these surfaces, excess solar heat can be collected and transferred into a borehole TES system, where it is stored underground. This reduces the amount of heat radiated back into the urban air, thus lowering ambient temperatures.
- Seasonal Storage and Use: The stored thermal energy can be used later, for example, as a heat source for building heating during colder months. This not only reduces the need for fossil fuel-based heating but also helps balance the urban thermal environment over time.
- Reducing Thermal Mass Effects: Cities with dense buildings and materials of high heat capacity tend to trap heat, creating “urban canyons” that block wind flow and cooling. By removing and storing thermal energy from these surfaces, TES decreases the magnitude of thermal masses and the heat they emit into the air, thereby moderating temperature spikes.
- Lowering Energy Consumption for Cooling: The UHI effect increases cooling demand in buildings, leading to higher energy consumption and additional waste heat release from air conditioning units, which further exacerbate urban temperatures. TES reduces this demand by stabilizing temperatures, which helps lower peak cooling loads, energy consumption, and the consequent heat rejection to the environment.
In summary, thermal energy storage acts as a buffer for urban heat by absorbing excess daytime heat and releasing it when needed, thus decreasing surface and air temperatures in cities. This reduces the intensity of the urban heat island effect, improves urban thermal comfort, and lowers energy use and emissions related to cooling.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/how-does-thermal-energy-storage-contribute-to-reducing-the-urban-heat-island-effect/
