Grantee Research Project Results
Final Report: Converting Energy from Reclaimed Heat: Thermal Electric Generator
EPA Grant Number: SU833164Title: Converting Energy from Reclaimed Heat: Thermal Electric Generator
Investigators: Baur, Stuart W. , Bartz, Navarre
Institution: University of Missouri - Rolla
EPA Project Officer: Page, Angela
Phase: I
Project Period: October 1, 2006 through May 1, 2007
Project Amount: $10,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2006) RFA Text | Recipients Lists
Research Category: P3 Challenge Area - Air Quality , Pollution Prevention/Sustainable Development , P3 Awards , Sustainable and Healthy Communities
Objective:
As the power grid in established nations grows, it becomes increasingly strained by the increasing demand for electricity by the citizens of its service area. In developing countries, the grid is unreliable or even non-existent, further complicating the divisions between the haves and the have-nots. As world commerce becomes more computerized, the gap between those with electricity and those without widens. A solution is needed that is both simple and inexpensive. One possible solution is distributed generation.
In a distributed generation system, there is not just one central power plant, but a series of smaller energy production facilities all tied into one grid. One of the most widely known forms of distributed generation is solar power. Solar energy collection takes two primary forms: thermal and electrical. Photovoltaic (PV) cells are the solar panels that typically come to mind when solar power is mentioned, and convert solar radiation into electricity. Thermal solar collection converts the solar radiation into heat which can then be used to heat water for household tasks or heat a home through radiant heating.
Something that has not been investigated thoroughly is the utilization of thermal solar power to make electricity. While some work has been done on a thermoelectric based concentrator arrangement, combining a solar PV system and thermal collection with thermoelectric devices is relatively uninvestigated. Thermoelectric efficiencies are relatively low when compared to solar power at ambient temperatures, but they show promise in aiding a combined solar thermal system.
Public education on the availability of such systems is also paramount. Many people believe solar power is a future technology not yet ready for public use. A program of public outreach will begin in mid-April in conjunction with this project. Visits will be conducted to area elementary and middle schools to show what is possible with solar power and try to spark the interest of young minds to pursue science and engineering, and to do it in an environmentally conscious manner. Getting young people excited about renewable energy will inspire adults as well, creating a ripe environment for acceptance of distributed generation technologies.
Summary/Accomplishments (Outputs/Outcomes):
Temperature difference in the Peltiers is the single most important aspect of their performance. The higher the difference between the hot source and cold sink, the higher the overall system efficiency. This is to be expected as the efficiencies should follow the tendencies of any heat engine. Those days with higher temperature differences showed a higher total amount of energy produced throughout the day.
While temperature difference is what influences the efficiencies of the Peltiers, the temperature difference is highly dependent on the amount of radiation available. The solar radiation is what causes the temperature difference to begin with in the solar system, and thus the more available radiation, the greater the temperature difference. The greater the temperature difference, the higher the efficiency, and also the higher the amount of power to convert into electricity. Cloudy weather causes a significant reduction in energy production due to the irregularity of available radiation. The lack of a constant radiation source results in a lower temperature difference and lower efficiency.
Currently, residential solar systems typically have efficiencies between 8% and 12%. While the Peltiers only have efficiencies on the order of 0.5% to 1.5% for the operating temperature differences, this can still have an effect on the overall power output of the unit. Assuming a 10% efficient solar array, one could get 500 watt-hours per square meter in a five hour period at full solar irradiation. Depending on temperature, one could presumably get up to 50 watt-hours per square meter from the Peltiers, a 10% increase in total power. This 50 watt-hours per square meter would allow a homeowner to run a 3-15 watt compact fluorescent light (CFL) for approximately four hours per square meter of array with a few watts to spare. Conceivably, the Peltier system could take over the task of lighting a home while the power produced by the array could be used for other tasks.
Conclusions:
Phase I research results showed that with the introduction of Peltier devices into the STEP hybrid solar system, a 10% increase in electrical production would be experienced. Economies of scale to reduce the cost of the Peltier devices would be required to make the combined Peltier STEP system an economic competitor with the original STEP system, however.
Proposed Phase II objectives and strategies:
The Phase II objectives and strategies include the further analysis and implementation of the data gathered in the first phase of this report by testing a larger scale model. The underlying drive for this research project is to increase the number of passive energy homes built in the U.S. and abroad. In so doing, an innovative building systems to increasing overall energy generation is being proposed. Specifically, the scope of this project focuses on increasing the overall energy generation by using a hybridized solar electric and thermal energy panel. The further development of this system would directly improve the building system efficiency and reduce the overall cost of living in a zero energy home.
It is the issue of affordability and convenience that directly impacts the “People” in the P3 grant. This problem definition is focused on the developed world, which has been remarkably slow to embrace sustainable building practices. The people need to see that a zero energy home can be more affordable than a traditional home and at the same time offer similar conveniences. In general, people purchase homes because of location and cost. It is this cost element that is being addressed in this proposal by developing a large-scale model of a combined photovoltaic and thermal hydronic energy system.
Journal Articles:
No journal articles submitted with this report: View all 1 publications for this projectSupplemental Keywords:
innovative technology, renewable, engineering, modeling, monitoring, Midwest, building systems, building industry, thermoelectric,, RFA, Scientific Discipline, TREATMENT/CONTROL, Sustainable Industry/Business, POLLUTION PREVENTION, Sustainable Environment, Energy, Technology, Technology for Sustainable Environment, Environmental Engineering, energy conservation, sustainable development, clean technologies, ecological design, environmental sustainability, energy efficiency, solar energy, photovoltaics, heat loss recapturingRelevant Websites:
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.