Radiative cooling device
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Solution Overview
Problem
Conventional HVAC systems are inefficient for individualized cooling needs, leading to excessive energy consumption and temperature differentials, while radiative cooling systems face challenges with condensation on cold surfaces.
Innovation Solution
A dry surface radiative cooling device that includes a housing, a permeable member, a first heat exchanger separated by a gap, and air flow paths for cooling and heat rejection, maintaining the permeable member above the dew point of the cooled air and below the dew point of ambient air.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If radiative cooling systems operate below the dew point temperature to achieve efficient cooling, then cooling performance is improved, but condensation forms on the cold radiative surface causing discomfort and potential damage
Solution Approach 1:
The device divides the cooling function into two separate components: a radiative cooling surface for heat removal and a permeable member for moisture management. This segmentation allows the radiative surface to operate below dew point for efficient cooling while the permeable member prevents condensation accumulation by allowing moisture to pass through.
Solution Approach 2:
A permeable member is introduced as an intermediary between the cold radiative surface and the ambient environment. This intermediary allows moisture vapor to pass through while preventing liquid condensation from forming on the radiative surface, thus resolving the contradiction between efficient cooling and condensation prevention.
2Ease of operation
If conventional HVAC systems cool the entire indoor space to meet individual cooling needs, then personal cooling comfort is improved, but energy consumption increases due to cooling unnecessary spaces
Solution Approach 1:
The device provides localized cooling at the personal level rather than cooling the entire space. By focusing the radiative cooling effect on a specific area or individual, energy is consumed only where needed, maintaining personal comfort without the penalty of cooling unnecessary spaces.
Solution Approach 2:
The radiative cooling device operates independently to provide personal cooling without requiring a centralized HVAC system to condition the entire space. Each device serves its local area autonomously, eliminating the energy waste associated with blanket cooling of entire buildings.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device provides efficient spot cooling while preventing exterior condensation, managing humidity, and reducing energy consumption by allowing recirculation of cooled air.
Implementation Method 1
Radiative cooling does not require movement of cold air over a human subject... Radiative cooling mimics the thermal effects of dark nighttime sky
Implementation Method 2
when operated below the dew point temperature of the ambient air, can cause condensation to form on the cold radiative surface
Data Source
AI summary
Provided is a dry surface radiative cooling device, including: at least one ambient air inlet; a housing comprising at least one cooled air outlet; a permeable member connected to the housing and comprising a permeable surface disposed at least partially adjacent to the at least one cooled air outlet; a refrigerant circuit disposed at least partially within the housing and comprising a first heat exchanger, wherein the first heat exchanger is separated from the permeable member by a gap; and a first air flow path disposed at least partially within the housing, extending between the at least one ambient air inlet and the at least one cooled air outlet and through the permeable surface, and at least partially defined by the gap between the surface of the first heat exchanger and the permeable member.