Teaching the Theory and Realities of Second Law Heating Systems

Frank Wicks

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Conference: 2012 ASEE Annual Conference & Exposition
Location: San Antonio, Texas
Publication Date: June 10, 2012
Start Date: June 10, 2012
End Date: June 13, 2012
ISSN: 2153-5965
Conference Session: Energy Education Courses, Labs, and Projects II
Tagged Division: Energy Conversion and Conservation
Page Count: 9
Page Numbers: 25.1260.1 - 25.1260.9
DOI: 10.18260/1-2--22017
Permanent URL: https://peer.asee.org/22017
Download Count: 415

Paper Authors

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Frank Wicks Union College

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Union College mechanical engineering professor Frank Wicks is a Past Chairman of the ASEE Energy Conversion and Conservation Committee. He is an ASME Fellow and frequent contributor to Mechanical Engineering magazine. He holds a B.Marine.E. from SUNY Maritime, a M.S.E.E. from Union College, and a Ph.D. in nuclear engineering from Rensselaer. He holds energy related patents and is a licensed Professional Engineer.

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Abstract

Teaching the Theory and Realities of 2nd Law Heating Systems In response to concerns about of global warming by CO2, fuel depletion and jobs there has been increasing interest in teaching renewable or Green Energy technologies which are typically defined as wind, solar and bio‐fuels. However, the most fuel conservation potential exists where the most is wasted, which the author asserts is the non‐obvious home furnace or heating system. The reason the home furnace is typically overlooked is the efficiency is typically defined in terms of the 1st Law, with resulting values as high as 96 % for the natural gas fueled condensing furnaces that have been available for the last generation. Thus, it is commonly, but incorrectly, assumed that the most efficient furnace would be 100 % efficient, and thus 96 % leaves very little room for improvement. However, it must be recognized that this represents a 1st Law efficiency, which is based on conservation of energy, and is defined as the ratio of space heat delivered to the heat value of the fuel that is burned. The 2nd law combines concepts of reversibility, entropy and temperatures on the hot and cold side and shows that even a 100 % efficient furnace has a high irreversibility because the heat is degraded from the high temperature combustion products down to the house temperature, which produces entropy which is a measure of waste. Thus, the ideal heating system would create no entropy, and can be achieved with an ideal fuel burning, or Wicks Cycle, engine powering an ideal, or Carnot Cycle, heat pump. Depending upon the maximum combustion temperatures an Ideal Engine can have an efficiency of 65 % and the ideal heat pump a Coefficient of Performance of 8. The resulting Effective Fuel Efficiency of 520 % which is the ratio of heat delivered to the space by the energy value of the fuel to the engine. This means that ideally the same amount of space heat can be delivered with 81.5 % less fuel. While practical considerations prevent the ideal from being achieved, there are potentially realistic systems that can be based upon this principle. Burning the fuel in a 25 % efficient engine that drives a heat pump with a COP of 4 and recovery of most heat from the engine exhaust and cylinder cooling an Effective Fuel Efficiency of 170 %. Similar systems are the Electricity Producing Condensing Furnace that was initiated by Frank Wicks and the Free Watt heating system that has been commercialized by Honda. The paper will describe how he teaches about the theory and practice of these kinds of 2nd law heating systems in a Heating Ventilation and Air Conditioning and in a Thermal Fluids systems course.

Citation
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Wicks, F. (2012, June), Teaching the Theory and Realities of Second Law Heating Systems Paper presented at 2012 ASEE Annual Conference & Exposition, San Antonio, Texas. 10.18260/1-2--22017

TY  - CPAPER
AB  -       Teaching the Theory and Realities of 2nd Law Heating Systems In response to concerns about of global warming by CO2, fuel depletion and jobs there has been increasing interest in teaching renewable or Green Energy technologies which are typically defined as wind, solar and bio‐fuels. However, the most fuel conservation potential exists where the most is wasted, which the author asserts is the non‐obvious home furnace or heating system. The reason the home furnace is typically overlooked is the efficiency is typically defined in terms of the 1st Law, with resulting values as high as 96 % for the natural gas fueled condensing furnaces that have been available for the last generation. Thus, it is commonly, but incorrectly, assumed that the most efficient furnace would be 100 % efficient, and thus 96 % leaves very little room for improvement. However, it must be recognized that this represents a 1st Law efficiency, which is based on conservation of energy, and is defined as the ratio of space heat delivered to the heat value of the fuel that is burned.  The 2nd law combines concepts of reversibility, entropy and temperatures on the hot and cold side and shows that even a 100 % efficient furnace has a high irreversibility because the heat is degraded from the high temperature combustion products down to the house temperature, which produces entropy which is a measure of waste. Thus, the ideal heating system would create no entropy, and can be achieved with an ideal fuel burning, or Wicks Cycle, engine powering an ideal, or Carnot Cycle, heat pump. Depending upon the maximum combustion temperatures an Ideal Engine can have an efficiency of 65 % and the ideal heat pump a Coefficient of Performance of 8. The resulting Effective Fuel Efficiency of 520 % which is the ratio of heat delivered to the space by the energy value of the fuel to the engine. This means that ideally the same amount of space heat can be delivered with 81.5 % less fuel. While practical considerations prevent the ideal from being achieved, there are potentially realistic systems that can be based upon this principle. Burning the fuel in a 25 % efficient engine that drives a heat pump with a COP of 4 and recovery of most heat from the engine exhaust and cylinder cooling an Effective Fuel Efficiency of 170 %. Similar systems are the Electricity Producing Condensing Furnace that was initiated by Frank Wicks and the Free Watt heating system that has been commercialized by Honda. The paper will describe how he teaches about the theory and practice of these kinds of 2nd law heating systems in a Heating Ventilation and Air Conditioning and in a Thermal Fluids systems course. 
AU  - Frank Wicks
CY  - San Antonio, Texas
DA  - 2012/06/10
PB  - ASEE Conferences
TI  - Teaching the Theory and Realities of Second Law Heating Systems
UR  - https://peer.asee.org/22017
DO  - 10.18260/1-2--22017
ER  -