A light shelf is a natural lighting system that prevents glare and improves uniformity by reflecting daylight into a room. In a perimeter zone where the light shelf is usually installed, there is a substantial need for cooling due to solar radiation. In this context, the concept of the light shelf using radiant cooling wherein a water pipe is embedded was proposed.
This study was conducted to evaluate the cooling capacity of a light shelf system integrated with a radiant cooling panel. For this purpose, a mock-up test chamber was developed, considering that the upper surface of the panel is exposed to the cooling load and indoor air as well as the lower surface. The mock-up tests were conducted with three panel layer configurations: thermal insulation filled between the upper and lower panel surfaces (INS), replacing the insulation to the air cavity (AIR), and installing the DC fans inside the panel (ARF).
Compared with the ''INS'' the cooling capacities of the ''AIR'' and ''ARF'' were increased by 9.4-29.4% and 22.7-53.0%, respectively. These enhancements were found when utilizing both panel surfaces as radiant cooling surfaces and promoting a convective/radiative heat transfer inside the panel. Using the results from the mock-up tests, the cooling capacity curves were derived to provide generalized performance data.
The mock-up test results were required to be verified in real space. For this reason, a field experiment was conducted in a Test-bed chamber replicating an office room where natural light inflowed. In the Test-bed chamber, the water pipe inside the light shelf panel is connected in series with a fan coil unit system. Through the field experiments, it could be validated against the enhancement of the cooling capacity with the panel layer configurations. Compared with the ''INS with FCU'', the cooling capacities of the ''AIR with FCU'' and ''ARF with FCU'' were enhanced by 21.2% and 44.4%, respectively. It was the same trend as that found in mock-up tests. Additionally, it has been found that connecting the FCU system to the light shelf panel allowed the pump operation time to be shortened. Also the temperature difference between the return water and supply water is greater than when the FCU system operated alone.