Focus

Research focused on identifying and exploiting thermal energy resources for the generation of carbon-free electrical power.

Highlights

• Thermal energy research involves diverse science. Physical scales of interest range from the nanoscale up to geographical scales.
• There are many fields of research at Penn State related to thermal energy, but no unified effort to promote interdisciplinary collaborations.
• Both technology development and robust integration strategies are necessary for future advances in waste heat utilization.

Goals

• Increase funding and activities through strategic investment in research related to thermal energy technologies.
• Make Penn State a leader in thermal-battery research for waste heat recovery and storage.
• Encourage collaboration across Penn State to solve technical and implementation challenges facing thermal energy technologies.

Overview

Thermal energy is both an important primary energy resource and also a byproduct of many industrial processes. Electrical power generation from thermal sources comes primarily from geothermal electricity generation and power conversion from industrial waste heat. Penn State has many thermal experts conducting research in a wide variety of areas, including power production (from geothermal, coal, gas, or nuclear sources), combustion systems, fundamental heat transfer physics, and high-performance materials. The opportunity exists to leverage Penn State’s thermal expertise for the development of advanced, carbon-free thermal energy technologies.
Geothermal power generation is the use of natural, high-temperature geothermal resources to generate steam or superheated gas for use in a power generation cycle. Geothermal power generation stations are typically installed where near-surface geothermal resources are abundant. The geothermal power generation capacity worldwide is currently equivalent to about 6 large-scale coal power plants and is projected to increase 40% by the year 2020.

Current research efforts are focused toward extending geothermal power generation to a wider range of geographical sites. Geothermal research activities at Penn State include:

• Simulating enhanced geothermal system implementation and performance
• Enhancing drilling and extraction technologies
• Understanding permeability and induced seismicity from fracturing processes.

Waste heat is thermal energy that is not utilized due to industrial process inefficiencies. Typical efficiencies of large-scale electrical power generation range from 25-44%, while heating systems may achieve efficiencies of over 80%. It is estimated that between 20% and 50% of all energy used by the industrial sector in the United States is lost through waste heat.

Waste heat can be recovered through storage and re-use or through conversion into electricity. The usability of waste heat is determined by its temperature, with sources below 230°C considered low-grade, between 230°C and 650°C considered medium-grade, and above 650°C considered high-grade with the most potential for energy conversion. It is estimated that over 90% of all waste heat is low- to medium-grade.

Technologies to improve waste heat recovery, storage, and re-use have historically seen a consistent level of research activity. Funding has primarily been through the Department of Energy (DOE), the National Science Foundation (NSF, which has a specific Thermal Transport Processes program) and through a variety of industry support. Current research activities at Penn State include:

• High-performance heat exchanger development
• Thermoelectric and pyroelectric materials
• Combined heat-and-power generation
• Building thermal energy storage
• Thermally-chargeable battery development

Thermal batteries are a particularly important opportunity area for research. They originated at PSU, provide long-term energy storage, and thus far achieve the highest power density for electrochemical low-grade waste heat conversion. With the support measures described below, Penn State can become a leader in this new and rapidly growing area of research.

Strategic Planning

The greatest future impact of renewable thermal energy resources will be achieved by more effectively capturing, storing, and converting low- and medium-grade waste heat and the development of next-generation geothermal power systems. Integrating waste heat storage and conversion systems into future energy-efficient and solar-powered buildings could also deliver an enormous impact.

Penn State should promote activities that enhance technological innovation and improve our understanding of thermal transport phenomena. A focus on the unique integration needs of these technologies should also be targeted. Penn State initiatives should encourage:

• Research on thermal batteries to gain knowledge of how new chemistries and convective transport affect power generation. Penn State can become a leader in this field.
• New material development for building thermal energy storage, including molten salt materials that are cost-effective and non-corrosive.
• Nano-material development that will lead to scalable materials for enhanced solid-state thermal energy scavenging.
• Phase-change system research that improves the efficiency and implementation cost of gas-liquid heat transport technologies.
• Technologies and strategies to minimize the capital cost and physical footprint of geothermal and waste heat recovery technologies.
• Advanced control systems for the integration of renewable and conventional thermal technologies with energy storage systems in cost- and policy-effective ways.
• Exploration of the nexus of solar energy and thermal energy storage for future buildings.
• Regulatory improvements that incentivize implementation of new technologies.

Specifically, Penn State can spur thermal-energy research through:

• Targeted seed grant funding to encourage continued growth in the research areas identified above, while also promoting new collaborative partnerships with industry or government labs.
• Cost-share rewards for successful interdisciplinary external proposals in thermal energy research.
• Uniting the diverse research areas related to thermal energy at Penn State by establishing a University-wide thermal energy research center.
• Leveraging this center to create new outreach programs to develop customized implementation plans for local communities to transition to renewable energy.
• Encourage fundamental-to-applied research activities by investing in large-scale physical test beds for technology demonstration.

List of Participants

• Primary contact
  • Matthew Rau, 301B Reber
• Participants
  • Bruce Logan
  • Derek Hall
  • Mark Stutman
  • Scott Wagner
  • James Freihaut
  • Derek Elsworth
  • Alex Rattner
  • Susan Stewart
  • Mike Manahan
  • Hojong Kim

Education and Outreach

• Departments
  • Engineering (Mechanical, Electrical, Architectural, Aerospace, Energy and Mineral, Civil)
  • Materials Science and Engineering
• Courses
  • Undergraduate
    • ME300
    • ME315
    • ME410
    • ME411
    • ME441
  • Graduate
    • ME512 (Conduction Heat Transfer)
    • ME513 (Convection Heat Transfer)
    • ME514 (Radiation Heat Transfer)
    • ME515 (Two-Phase Heat Transfer)
    • ME523 (Numerical Methods in Heat and Mass Transfer)
    • EGEE 497 (Sustainable Energy in New Zealand and Geothermal Energy Engineering)
  • World campus
    • See ME500-level courses above
• Potential Outreach activities
  • DOE Student Geothermal Competition
  • Home appliance energy efficiency research programs for secondary school students

Supplemental Information

Graphics: (https://psu.box.com/v/Energy2100-Thermal)