Energy Quote

The state's combination of abundant renewable resources, high fuel prices, limited geographic area, and recognized expertise in hydrogen technology R&D, makes it an ideal location to lead the state's transition to a renewable energy-to-hydrogen economy. By attracting considerable investments of capital and expertise to Hawaii, we will be investing wisely for our future needs.

Ted Liu

Radiant Cooling

A cooling system that relies on temperature-controlled surface (ceiling, wall or floor) to cool indoor temperatures by removing sensible heat through thermal radiation. Heat will flow from objects, occupants, equipment and lights in a space to a cooled surface as long as their temperatures are warmer than that of the cooled surface and they are within the line of sight of the cooled surface. The process of radiant exchange has a negligible effect on air temperature, but through the process of convection, the air temperature will be lowered when air comes in contact with the cooled surface.

The majority of radiant cooling systems are hydronic, cooling using circulating water running in pipes in thermal contact with the surface. Due to the high heat capacity and density of water, thermal energy can be transported in water in pipes by low power pumps, saving approximately 70 to 80% of fan power normally used in conventianal air-conditioners.

Typically the circulating water in hydronic radiant cooling (HRC) only needs to be 2-4°C below the desired indoor air temperature. Since the coolant can be maintained at a high temperature level, the use of heat pumps with high coefficient-of-performance values, cooling towers, night cooling, or some combination of these can reduce electric power requirements further.

7 Jun 2011 19:50:23

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