Date on Master's Thesis/Doctoral Dissertation

5-2009

Document Type

Master's Thesis

Degree Name

M. Eng.

Department

Mechanical Engineering

Committee Chair

Sharp, Michael Keith

Subject

Solar heating--Research; Solar energy--Research

Abstract

The heat pipe augmented solar wall operates much more efficiently for domestic air heating than alternative passive solar technologies. The thermal diode effect of heat pipes reduces the insulating losses of the unit during nighttime and adverse solar conditions. The exceptionally high conductivity of heat pipes allows for much greater heat gains, and significantly reduces the response time of the unit. The response time is also reduced by a smaller thermal mass of preheating components, which allows the system to passively alternate between insulating and heating conditions much more quickly. By separating the thermal mass of the system from external cold temperatures through the use of insulation and heat pipes, the insulation values of the unit are larger than that of other passive devices. A heat pipe augmented solar wall was designed with emphasis on thermal efficiency and mass manufacturing techniques. Design drafts, solid models, and assembly and production instructions were created to assist and spur future production of these units. Detailed consumer and producer economic analysis of the unit was also performed. The cost of the approximately four foot wide by seven foot tall domestic heating unit to be produced, shipped, and installed is projected to be $1580 with current tax credits. Economic analysis yielded a payback period of 14 years and a 30 year return on investment of 130% based on Louisville, KY weather and East Central United States utilities. A full-scale experimental heat pipe augmented solar wall was constructed as close as possible to the mass production design and was installed in a classroom at the University of Louisville. The unit was tested under actual weather conditions from April 1-21, 2009. Weather conditions for testing included clear, cloudy, rainy, and snowing and outside temperatures ranged from 4-24 degrees Celsius. Efficiency of the experimental unit ranged from approximately 60-75% under various solar radiation and ambient temperature values, all of which by necessity were at a high incidence angle. Efficiencies upwards of 80% are estimated for peak solar insolation conditions and low incidence angle.

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