June 22, 2008
June 22, 2008
June 25, 2008
Energy Conversion and Conservation
13.329.1 - 13.329.14
Construction of a Radiant Cooling and Control Demonstration Unit for Use in Engineering Courses
Radiant cooling is a method commercially used to provide a level of human comfort without relying solely on forced convection. Operating under the same basic principles as radiant heating, this method functions by providing a cooled surface which will absorb radiated heat from other objects, such as a person. While radiant cooling exhibits several advantages few applications of this technique are available for students to study. Few engineering students, therefore, have heard of the technique or know anything about it. The intention of this project was to produce a radiant cooling demonstration unit which can be used to introduce radiant cooling techniques. Additionally, acquisition of sensor signals and computer management of the equipment will allow students to explore methods of controlling a simple HVAC system.
Through a grant from the American Society of Heating, Refrigeration, and Air Conditioning Engineers (ASHRAE) the demonstration unit was designed and constructed as part of an undergraduate senior project during the 2005-2006 academic year. The unit is fully instrumented through the LabVIEW software package for a variety of uses. A graduate student is currently performing characterization experiments with the unit in an environment chamber. For the next stage of development appropriate automatic control software will be written using LabVIEW. This paper will detail the design and construction of the demonstration unit and will present basic data on its use.
Radiant cooling is a method commercially used to provide a level of human comfort without relying solely on forced convection. The basic principles of radiant cooling are similar to that of radiant heating. Radiant cooling works by providing a chilled surface that will absorb radiated heat from surrounding objects. An object that is hotter in temperature than the cooling surface will emit a net thermal radiation to the cool surface. As the thermal energy is received it is transferred to a secondary medium, in this case chilled water, to be removed. Convective heat transfer will also occur between the air and the cool surface of the panel. The performance of the system depends on how well it can receive energy by the combination of thermal radiation and convective heat transfer from the air. However, radiant cooling panels are defined as a source of cooling which has at least 50% of the heat transfer via radiation . Cooling panels can be made in various forms but are generally designed to replace existing drop down ceiling panels. They are ideally suited for applications which already have access to a chilled water distribution system.
The benefits of radiant cooling panels mainly derive from a reduction in the required air flow rate for the HVAC system. As more of the cooling load is handled by the panels the air flow rate can be reduced to the point of simply satisfying ventilation requirements. From an energy perspective, the pump work is much less than the fan work so radiant panels tend to be more
Tebbe, P., & Weninger, B., & Thibeault, C. (2008, June), Construction Of A Radiant Cooling And Control Demonstration Unit For Use In Engineering Courses Paper presented at 2008 Annual Conference & Exposition, Pittsburgh, Pennsylvania. https://peer.asee.org/4056
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