Related Experiment Video
Updated: Sep 10, 2025
07:18
Experimental System of Solar Adsorption Refrigeration with Concentrated Collector
Published on: October 18, 2017
14.7K
High-Thermal-Conductivity Radiative Cooling Films for Enhanced Passive Daytime Cooling
Shijin Nie1, Lizhan Bai1, Guiping Lin1,2
1Laboratory of Fundamental Science on Ergonomics and Environmental Control, School of Aeronautic Science and Engineering, Beihang University, Beijing 100191, P. R. China.
ACS Applied Materials & Interfaces
|August 27, 2025
Summary
This study introduces a new radiative cooling film (DPHA film) that enhances cooling efficiency by integrating internal thermal channels. The DPHA film demonstrates superior performance, offering a significant temperature difference for passive daytime radiative cooling applications.
Area of Science:
- Materials Science
- Thermodynamics
- Sustainable Energy
Background:
- Passive daytime radiative cooling (PDRC) offers energy-saving cooling by reflecting sunlight and emitting heat.
- Practical PDRC is limited by heat flow irreversibility, hindering maximum cooling potential.
- Developing advanced radiative cooling materials is crucial for efficient thermal management.
Purpose of the Study:
- To develop an integrated radiative cooling (RC) film with high thermal conductivity for enhanced cooling performance.
- To overcome the limitations of conventional radiative cooling materials by improving heat dissipation.
- To assess the optical properties, thermal conductivity, and durability of the novel RC film.
Main Methods:
- Fabrication of an integrated radiative cooling film (DPHA film) with internal thermal channels.
- Characterization of optical properties, including solar reflectivity and infrared emissivity.
- Measurement of temperature difference under solar irradiation and assessment of thermal conductivity.
- Evaluation of aging resistance under continuous UV irradiation.
Main Results:
- The DPHA film achieved superior optical properties (reflectivity ~0.96, emissivity ~0.98).
- A maximum temperature difference of 17.5 °C and an average of 13.2 °C were recorded under 977 W m⁻² solar intensity.
- The film exhibited high out-plane thermal conductivity (0.755 W m⁻¹ K⁻¹), facilitating efficient heat dissipation.
- The DPHA film demonstrated excellent optical properties and aging resistance after 30 days of UV exposure.
Conclusions:
- The developed DPHA film significantly improves radiative cooling performance through enhanced thermal conductivity and optimized optical properties.
- The film shows great potential for scalable and cost-effective outdoor cooling applications.
- This work presents a novel approach for developing high-performance radiative cooling materials.
Related Concept Videos
01:20Conduction, Convection and Radiation: Problem Solving
1.4K
There are three methods by which heat transfer can take place: conduction, convection, and radiation. Each method has unique and interesting characteristics, but all three have two things in common: they transfer heat solely because of a temperature difference; and the greater the temperature difference, the faster the heat transfer.
In order to solve a problem related to heat transfer, first of all, the situation needs to be examined to determine the type of heat transfer involved. This could...
In order to solve a problem related to heat transfer, first of all, the situation needs to be examined to determine the type of heat transfer involved. This could...
1.4K
01:17Radiation: Applications
1.2K
The average temperature of Earth is the subject of much current discussion. Earth is in radiative contact with both the Sun and dark space; it receives almost all its energy from the radiation of the Sun and reflects some of it into outer space. Dark space is very cold, about 3 K, so Earth radiates energy into it. For instance, heat transfer occurs from soil and grasses, the rate of which can be so rapid that frost can occur on clear summer evenings, even in warm latitudes.
The average...
The average...
1.2K
01:22Thermal Insulation in Masonry Walls
188
In hot, dry climates, the thermal mass of masonry walls can be beneficial, absorbing heat during the day and releasing it at night, thereby stabilizing indoor temperatures. However, in most other climates, additional insulation is necessary to enhance thermal resistance.
External insulation can be applied using an Exterior Insulation and Finish System (EIFS), which involves affixing panels of plastic foam to the wall and covering them with a polymeric stucco reinforced with glass fiber mesh....
External insulation can be applied using an Exterior Insulation and Finish System (EIFS), which involves affixing panels of plastic foam to the wall and covering them with a polymeric stucco reinforced with glass fiber mesh....
188
01:20Mechanisms of Heat Transfer II
3.5K
In convection, thermal energy is carried by the large-scale flow of matter. Ocean currents and large-scale atmospheric circulation, which result from the buoyancy of warm air and water, transfer hot air from the tropics toward the poles and cold air from the poles toward the tropics. The Earth’s rotation interacts with those flows, causing the observed eastward flow of air in the temperate zones. Convection dominates heat transfer by air, and the amount of available space for the airflow...
3.5K
01:19Mechanism of heat transfer
1.4K
Understanding heat transfer mechanisms is essential for understanding how our bodies maintain balance in different environmental conditions. When the environment is thermoneutral, the body is in a state of balance, neither using nor releasing energy to maintain its core temperature. However, when the environment is not thermoneutral, the body employs four heat transfer mechanisms to maintain homeostasis: conduction, convection, evaporation, and radiation. These mechanisms facilitate heat...
1.4K
01:14Mechanisms of Heat Transfer
500
Heat transfer between the human body and its environment occurs through four main mechanisms: conduction, convection, radiation, and evaporation.
Conduction, accounting for approximately 3% of body heat loss at rest, is the process of exchanging heat between molecules of two materials in direct contact. This can result in both heat loss and gain. For instance, when the body is submerged in water, which conducts heat 20 times more effectively than air, it can either lose or gain significant...
Conduction, accounting for approximately 3% of body heat loss at rest, is the process of exchanging heat between molecules of two materials in direct contact. This can result in both heat loss and gain. For instance, when the body is submerged in water, which conducts heat 20 times more effectively than air, it can either lose or gain significant...
500