lin-shu wang

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Papers by lin-shu wang

PWM Control of a Cooling Tower in a Thermally Homeostatic Building

American journal of mechanical engineering, 2015

Thermal Homeostasis in Buildings (THiB) is a new concept of building conditioning. Since summer c... more Thermal Homeostasis in Buildings (THiB) is a new concept of building conditioning. Since summer cooling is the more challenging of building conditioning, several earlier papers focused on the study of natural summer cooling by using cooling tower (CT). The goal was to show the possibility and conditions of natural cooling, i.e., under what extreme day by day conditions that it is still possible for natural cooling to keep indoor temperature from exceeding a given maximum value: since no consideration was given to limiting indoor temperature above a minimum, in fact CT overcooling would be the problem for most part of the summer. This paper presents a fuller consideration of continual operation of a CT throughout the whole summer with pulse-width modulation (PWM) control of the tower operation. The goal here is to find to what extent the indoor temperature can be kept within the comfort zone. To put it another way, determine whether hours or percentile of hours out of total annual ho...

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INTERCOOLING-SUPERCHARGING PRINCIPLE : Part I-Reduction of Exhaust Heat Loss From Internal Combustion Engines by Intercooling-Supercharging

Simple-cycle" internal combustion engines (gasoline engine, diesel engine, and simple-cycle ... more Simple-cycle" internal combustion engines (gasoline engine, diesel engine, and simple-cycle gas turbine) are designed at or near optimal peak cycle pressure for maximum power output and thermal efficiency. Significant heat loss remains. however, in the exhaust of these optimally-designed internal combustion engines. Various methods for improving fuel economy have been proposed based on the straight-forward principle of exhaust heat recovery. Though successfully used for stationary powerplant and marine propulsion, these often bulky advanced systems are unsuitable for applications that require compactness and high power density. Alternative cycles that directly reduce exhaust heat loss were proposed recently. As reduction means rather than recovery means, the new cycles may lead to compact engines of high efficiency. This paper discusses the common underpinning of the new cycles--the intercoolingsupercharging principle-and its theoretical origin, and reviews the simulation-study...

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Effective heat capacity of interior planar thermal mass (iPTM) subject to periodic heating and cooling

Energy and Buildings, 2012

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Modeling of TABS-based thermally manageable buildings in Simulink

Applied Energy, 2013

h i g h l i g h t s " An RC model of a TABS-equipped thermally manageable building is built in Si... more h i g h l i g h t s " An RC model of a TABS-equipped thermally manageable building is built in Simulink. " Manageability requires correct selection of TABS thermal mass and envelope resistance. " A manageable building with the right mass-envelope combination functions robustly. " Operative temperature level can be maintained by low-power equipment as cooling tower. " Operative temperature variation is primarily a function of thermal mass and resistance.

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Reversible Processes Versus Quasi-static Processes, and the Condition of Internal Reversibility

A presupposition in the naturalistic sciences is that laws should be centered on a natural object... more A presupposition in the naturalistic sciences is that laws should be centered on a natural object in itself without having to involve a man-made machine. That is the legacy of Newtonian science of mechanical objects as mass bodies. A strong movement in equilibrium thermodynamics initiated by Caratheodory has been based on this presupposition. This disquisition rejects naturalistic presupposition and the Caratheodory formalism by pointing out the unique nature of thermodynamic objects as systems with essential design characteristics. This chapter applies Prigogine’s modern formalism for the effective treatment of system–surroundings interactions for a better understanding of thermodynamic processes.

A Theory of Heat as Prelude to Engineering Thermodynamics

Profitable handling of extracted energy in accordance with the energy conversion doctrine has ser... more Profitable handling of extracted energy in accordance with the energy conversion doctrine has served well expediency for industrialization. Despite that success, this disquisition refutes the energy conversion doctrine in favor of entropy-growth-potential-centric (EGP-centric) approach that is necessary for achieving efficiency rather than expediency. With the new theory of heat, this chapter outlines a philosophical prelude to engineering application of thermodynamics. Though decision is made to separate the project of a textbook on engineering thermodynamics from this disquisition so that details of the textbook project will be worked out after further deliberation, such an engineering thermodynamics text will articulate the distinctive characterization of engineering in terms of physical necessity and causal necessity. It is also anticipated that causal necessity addressed in the textbook project will incorporate solutions, in addition to conventional energy solutions, based on n...

MIXPC Turbocharging System for Diesel Engines

SAE Technical Paper Series, 2006

Continuous-Combustion Gas Generator Engine: Zero-Dimensional Modeling Study

SAE Technical Paper Series, 1993

The Gas Generator Engine - A New Family of Internal Combustion Engines

SAE Technical Paper Series, 1992

Exergy or the entropic drive: waste heat and free heat

International Journal of Exergy, 2013

ABSTRACT

Clausius’ thermodynamics, engineering thermodynamics based on the entropy principle by discarding the energy premise

Thermodynamics is the theory of energy resulted from the conceptual differentiation of caloric, c... more Thermodynamics is the theory of energy resulted from the conceptual differentiation of caloric, circa 1850-1865, into energy, entropy, and heat (a disorganized form of energy) in terms of the two laws of thermodynamics, the first law and the second law. The theory is often referred to as the Clausius-Kelvin theory as a single theoretical system. In actual fact, it is a blend of Kelvin's contribution and Clausius' contribution. Orthodox engineering thermodynamics is instead an update of the energy physics formulated by Kelvin circa 1850-55 based on the energy premise, which stops short of the conceptual differentiation in the exact sense. It is the Clausius version of the theory that was transformed by Gibbs into Gibbsian thermodynamics, which is the result of the conceptual differentiation. As a result, engineering thermodynamics is a defective theoretical system while Gibbsian thermodynamics is a successful one. This paper makes the case that Clausius' theorem of entropy can be developed for reforming engineering thermodynamics into a coherent system by rejecting the energy premise.

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A Treatise of Heat and Energy

Mechanical Engineering Series, 2020

Calorimetry and the Caloric Theory of Heat, the Measurement of Heat

A Treatise of Heat and Energy, 2019

Joseph Black distinguished between the quantity of heat in a body and its intensity, or temperatu... more Joseph Black distinguished between the quantity of heat in a body and its intensity, or temperature, which was introduced in Chap. 1. This chapter introduces calorimetry, the measurement of the quantity of heat, and the contemporary theory of heat, the caloric theory of heat. Development of calorimetry and the caloric theory was the beginning of the quantitative study of heat, and the important stepping stone toward the mechanical theory of heat, the idea that heat is a form of energy.

Free Energy, Exergy, and Energy: The Exergetic Content of Energy

A Treatise of Heat and Energy, 2019

Kelvin had introduced the general idea of available energy. The advent of the entropy principle l... more Kelvin had introduced the general idea of available energy. The advent of the entropy principle led to, in quick succession, the formulation of equilibrium thermodynamics by Gibbs—which was the prized fruit of the Kelvin–Clausius synthesis. One of its important results was the concept of free energies, which provided the general idea of available energies with specific examples—especially the Gibbs free energy of electrochemical energy→electrical work. Further development of available energy has evolved into the theory of exergy. Significantly, both the first law and the theory of exergy can be formulated for an engineering device’s control volume. In that formulation, the exergy treatment is reducible to the Carnot–Kelvin formula, a key tool in mechanical engineering, as well as to the Gibbs free energy, a key tool in chemical engineering.

Entropy and the Entropy Principle

Clausius generalized the mathematical expression of Carnot’s principle obtained by Kelvin, and in... more Clausius generalized the mathematical expression of Carnot’s principle obtained by Kelvin, and in 1865, introduced the concept of entropy and formulated the entropy principle. With the concept of entropy and the idea of the entropy principle, a definition of heat can be given, as well as mathematical formalism on equilibrium thermodynamics was formulated for organizing empirical data of thermodynamic properties. The establishment of the entropy principle signaled the beginning of a new era—in which, thermodynamics, which had originated as a branch of engineering knowledge, separated into two distinctive streams. The new science stream was manifested in the mathematical formalism on equilibrium thermodynamics. It is noted that the entropy principle, rather than the energy principle, is the true universal principle.

Carnot’s Theory of Heat, and Kelvin’s Adoption of Which in Terms of Energy

A Treatise of Heat and Energy, 2019

MEH surmised work production to be resulting from the consumption of heat. Carnot demonstrated th... more MEH surmised work production to be resulting from the consumption of heat. Carnot demonstrated that work production is derived from the transfer of heat. Kelvin and Clausius were able to synthesize the two competing theories into one theory by incorporating Carnot’s theory to accord for what was meant by “consumption”. This chapter covers Carnot’s theory of heat and how Kelvin incorporated Carnot’s theory into the MTH in terms of absolute thermodynamic temperature, the Carnot–Kelvin formula, and the concept of available energy and the energy principle, which is Kelvin’s version of the second law of thermodynamics. That is, Kelvin formulated a thermodynamics theory in terms of energy: in terms of energy conservation and energy availability, as well as the universality in the direction of energy form transformation.

Application of Exergy: A Low-Exergy Solution to Building Heating and Cooling

Application of Exergy, 2018

Considering heat a form of energy, the mechanical theory of heat (MTH), in making this historic a... more Considering heat a form of energy, the mechanical theory of heat (MTH), in making this historic advance of heat's ontological-category, made a relational-category error. The resulting energetic viewpoint of MTH sees all changes in nature as energy conversions and the problem of building heating and cooling as, quantitatively, energy-demand-andsupply problem. The IEA-ECBCS-programme introduced a correction to this energetic bias with the principle of "matching the quality levels between the energy supply and demand," which is known as LowEx approach. A recently formulated theory of heat, the predicative entropic theory of heat (PETH), is based on the cornerstone of correct categories of heat ontologically as well as predicatively (relationally). In the new theory, heat extraction plays a central role and, therefore, changes in nature are seen in terms of spontaneous entropy growth and heat extraction as powered by entropy growth potentials (EGPs). An alternative to the IEA-ECBCS's LowEx approach is suggested here based on heat extraction. Instead of matching of quality levels, LowEx can also be achieved by the management of natural EGPs: the combined solar and heat pump systems (S+HPs) can be transformed into LowEx S+HPs, a pure heat extraction system, by "eliminating" the energy conversion process of auxiliary heating.

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Causal efficacy and the normative notion of sustainability science

Sustainability: Science, Practice and Policy, 2011

Sustainability science requires both a descriptive understanding and a normative approach. Modern... more Sustainability science requires both a descriptive understanding and a normative approach. Modern science, however, began as purely descriptive knowledge, the core of which is that matter is dynamically inert and without purpose. The British philosopher David Hume concluded that the only type of causation in the material world is "efficient causation," which supported this purposeless view of a deterministic world "governed" by the causal laws of dynamics. But Hume did not argue against the existence of efficacious causation, only the error of humans projecting the mind's efficacy to objects. Though dynamically inert, a material object away from equilibrium can be thermodynamically reactive, suggesting the possibility of the object being efficaciously managed for a purpose. Furthermore, quantum physics has replaced classical physics as the fundamental theory of the material world. Its basic equation, the Schrödinger waveequation, is deterministic but causally inert-it cannot govern, leaving the determinism door unlocked. This causal gap, according to the von Neumann-Stapp quantum measurement/activation theory, necessitates the pragmatic existence in an irreversible universe of the causal efficacy of mental effort and information management. The resulting "bigger" empirical science has room for "descriptive determinism" and "normative action," both of which are utterly essential in formulating sustainability science as an integral discipline.

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Optimum Peak Cycle Pressure for the Intercooled-Supercharged Gas Turbine Engine

Volume 2: Aircraft Engine; Marine; Microturbines and Small Turbomachinery, 1995

Performance (thermal efficiency and mass specific power) of a simple-cycle gas turbine increases ... more Performance (thermal efficiency and mass specific power) of a simple-cycle gas turbine increases monotonically with peak cycle temperatures, for a given peak cycle temperature, the performance also depends on cycle pressure ratio or peak cycle pressure: maximum performance (both mass specific power and thermal efficiency near their maximum values) is achieved in a narrow range of optimum peak cycle pressures. A recently proposed intercooled-supercharged cycle gas turbine differs from the conventional intercooled cycle gas turbine in their intercooler placement. This paper studies the performance of the proposed cycle based on a reformulated intercooling-supercharging optimization procedure. The intercooler placement is defined by a new parameter, the intercooling supercharging parameter. In terms of the intercooling supercharging parameter and the peak cycle pressure, a map of performance curves (efficiency versus specific power) is constructed, which discloses a higher performance ...

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Modeling of hydronic radiant cooling of a thermally homeostatic building using a parametric cooling tower

Thermal Homeostasis in Buildings (THiB) is a new concept consisting of two steps: thermal autonom... more Thermal Homeostasis in Buildings (THiB) is a new concept consisting of two steps: thermal autonomy (architectural homeostasis) and thermal homeostasis (mechanical homeostasis). The first step is based on the architectural requirement of a building's envelope and its thermal mass, while the second one is based on the engineering requirement of hydronic equipment. Previous studies of homeostatic building were limited to a TABSequipped single room in a commercial building. Here we investigate the possibility of thermal homeostasis in a small TABS-equipped building, and focus on the possibility of natural summer cooling in Paso Robles, CA, by using cooling tower alone. By showing the viability of natural cooling in one special case, albeit a case in one of the most favorable locations climatically, a case is made that the use of cooling tower in thermally homeostatic buildings should not be overlooked for general application in wider regions of other climatic zones.

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