Thermoeconomics

ABSTRACT Thermo–economic analysis of Heat Pipe Heat Exchanger (HPHE) for waste heat recovery in thermal systems using the P1–P2 and NTU methods is presented. The optimum effectiveness of a HPHE is given as a polynomial equation, whereas the net savings and payback period are given in closed form to enable the HPHE designer to determine the optimised values directly. In addition to this, exergy analysis of HPHE for waste heat recovery in thermal systems is formulated. The variation of exergy efficiency with respect to change in inlet temperature is also presented.

This paper presents sensitivity and resilience analyses for a trigeneration system designed for a hospital. The following information is utilized to formulate an integer linear programming model: (1) energy service demands of the hospital, (2) technical and economical characteristics of the potential technologies for installation, (3) prices of the available utilities interchanged, and (4) financial parameters of the project. The solution of the model, minimizing the annual total cost, provides the optimal configuration of the system (technologies installed and number of pieces of equipment) and the optimal operation mode (operational load of equipment, interchange of utilities with the environment, convenience of wasting cogenerated heat, etc.) at each temporal interval defining the demand. The broad range of technical, economic, and institutional uncertainties throughout the life cycle of energy supply systems for buildings makes it necessary to delve more deeply into the fundamental properties of resilient systems: feasibility, flexibility and robustness. The resilience of the obtained solution is tested by varying, within reasonable limits, selected parameters: energy demand, amortization and maintenance factor, natural gas price, self-consumption of electricity, and time-of-delivery feed-in tariffs.

... Various criteria in optimization of a geothermal air conditioning system with a horizontal ground heat exchanger Hoseyn Sayyaadi Ć,y and Emad Hadaddi Amlashi Faculty of Mechanical Engineering—Energy Division, KN Toosi University of Technology, Tehran, Iran SUMMARY ...

This dissertation is a result of three years of research in the field of Advanced Exergy Analysis, with particular emphasis on the following issues;

• Input-Output benchmarking to perform Thermoeconomic Analysis of the Energy Conversion Systems.
• Adaptation of the Thermoeconomic Input-Output Analysis method for the Diagnosis of energy conversion systems.
• Derivation of stand-alone and reduced order Thermoeconomic Input-Output Analysis model that can be implemented by even non-expert industrial practitioners to investigate the interdependencies between the components and performance behavior of the system during the on- and off-design working condition.

Context and motivation
Power generation is an important factor in the development of any economy. Over the past decade, gas turbines have turned out to be one of the most interesting techniques for producing electricity and being implemented in various energy intensive industrial plants. In 1990s, due to the low fuel prices, combined cycle power plants were designed for base load working condition. However, changing market conditions due to the pervasiveness of renewables, unpredictable fluctuation of fuel price, and demand reduction due to economic crises, pushed combined cycle power plants to operate in intermediate or even daily cycling mode. Cycling refers to the operation of electric generating units at variable loads, including on/off, which shortens component lifetime, increases failure rate, and raises the operation and maintenance (O&M) costs.  Such additional costs make the power generation units less competitive in the liberalized power market. Therefore, it is crucial for the operators of such utilities to better understand the underlying nature of their plant O&M costs through the detailed Thermodynamic and Thermoeconomic analysis of systems, and performing proper diagnosis procedure.
There exist several methodologies to perform Thermoeconomic analysis of the energy conversion systems. These techniques, however; are debatable due to lack of solid classification as well as poor industrial orientation stem from high level of computational requirements. This work aims to fill those gaps by benchmarking the methodologies to define and to solve the Thermoeconomic problem, and to decrease the impediments between research and practice by reducing the complexity of the Thermoeconomic analysis. To do so, two well-established benchmarks, namely, CGAM and TADEUS are employed for the purpose of description and comparison of methodologies, and to highlight strengths, weaknesses and differences among those methods. Furthermore, the issue of exergy cost reallocation of the residual flows is investigated and formalized by the aid of Input-Output method.  The mathematical layout of the Input-Output method makes it suitable for such kind of analysis.
Thermoeconomic Input-Output Analysis (TIOA) method is then enhanced for the diagnosis purposes, elaborating on the specific characteristic of the Input-Output method, which investigates the interdependencies between the components.  An innovative approach is proposed and formalized to identify the influence of each individual component on the malfunctioning of the other components. The new approach is called Malfunction Decomposition (MD) and it is applied to the well-established CGAM benchmark to highlight the advantages over other Thermoeconomic diagnosis methodologies. According to the state of the art provided in this thesis, most of the approaches in the field of Thermoeconomic diagnosis are aimed to localize the anomaly and to quantify the inefficiencies caused by the anomaly in terms of additional fuel consumption or economic expenses.  In these cases, even if the operator detects the source of the anomaly, sometimes it is very difficult or impossible to act properly on that component during the operation of the system. Localization and quantification of the anomaly might be useful to predict the failure time or the maintenance schedule of the anomalous component. Therefore, unpredictable stoppage or failure of the system may reduce. In this thesis instead, it is rigorously demonstrated that MD can further assist the operators, providing practical information to reduce the inefficiencies causes by anomaly, once the system is operating. It provides a clear picture of malfunction structure and pinpoints the most influential component where intervention may take place to reduce the inefficiencies.
Finally, Thermoeconomic Input–Output Analysis model is proposed for the on- and off-design performance prediction of energy systems, and applied to La Casella Natural Gas Combined Cycle (NGCC) power plant, in Italy. The model is a stand-alone and a reduced order model, where the Thermoeconomic performance indicators are derived for on- and off-design conditions as functions of the load and of different control mechanisms, independently from the detailed Thermodynamic model. The results of the application show that the Thermoeconomic Input–Output Analysis model is a suitable tool for power plant operators, makes them capable to derive the same information as the traditional Thermoeconomic Analysis models while providing less complexity and computational effort.

Contribution of the research to the scientific advancement
Contribution of this research to the scientific advancement in the field of Thermoeconomic analysis and Thermoeconomic diagnosis of the energy conversion systems can be categorized as follows;

• Input-Output benchmarking. Proper method to perform the Thermoeconomic analysis of the energy conversion system has been benchmarked through the comparative application of existing methodologies on the two well-known benchmarks in the field of Thermoeconomic (CGAM and TADEUS). Moreover, the issue of exergy cost reallocation of the residual flow has been formalized for each method. Input-Output emerged as a suited and effective method to perform Thermoeconomic Analysis knowing as TIOA. It’s a synthesis of Input-Output method with Exergy Cost Theory, to obtain Thermoeconomic parameters through the well-formalized approach.  The straight forward mathematical structure, easiness of implementation, flexibility, and capability to investigate interdependencies between the components are the main characteristics of the Input-Output method which make it suitable for the purpose of Thermoeconomic analysis.
• Input-Output adaptation for the Thermoeconomic diagnosis purpose.  A novel approach is developed to decompose the malfunction, taking advantage of important characteristic of Input-Output method to depict the interrelation between the components. Such decomposition enables operators or analysts to face with malfunctioning working condition with a clear picture of malfunction’s structure and to minimize the inefficiencies caused by anomaly.
• Derivation of stand-alone and reduced order TIOA model. Application of the selected and adapted methodology on a real and complex energy conversion system provides a practical tool to be easily implemented by the practitioners to perform Thermoeconomic analysis.

The sugar and ethanol production is one of the most important economical activities in Brazil, mainly due
its high efficiency and competitiveness. The ethanol production is done by several steps: juice extraction,
treatment, fermentation and distillation. The juice extraction and treatment is a common operation of both
industries sugar and alcohol. The process begins with the sugar cane juice extraction, usually done by
devices namely mills, where the cane is compressed between big cylinders for the separation of the juice
from the bagasse. Recently, another juice extraction system named diffuser was introduced in some sugar
and alcohol factories. On diffusers, after sugar cane preparation stage, done with knives and shredders, it
passes through a bed, where the juice is separated from bagasse by the addition of imbibition water and
steam, in a lixiviation process. This study evaluates these two juice extraction systems, performing an
exergetic cost analysis. The total production plant is treated, considering the most important process
sections: cogeneration, extraction and distillation and their products: electric energy, cane juice and
hydrated ethanol, respectively. The results of exergetic efficiency, irreversibility generation and unitary
exergetic cost of products are analyzed and compared.
Keywords: sugar cane juice, extraction system, exergetic cost analysis

This thesis deals with the thermoeconomic analysis of four geothermal power cycles proposed for utilization of superheated steam from IDDP-1. These cycles mainly consider mitigation techniques applied for the removal of the chloride present in the fluid. Through executing a comparative thermoeconomic analysis, this research highlights the importance of the correlation between exergetic efficiency, exergy costing and capital costs. Exergy analysis and cost estimation were performed for each component and for the cycles as a whole. The cycles were proposed in literature and are designed to process efficient chloride-induced corrosion mitigation techniques to be applied to the world’s first magma-EGS well, IDDP-1. The work compares four cycles, three of them apply wet scrubbing technique while the fourth is a binary cycle. The base case cycle considered in this study is a single flash cycle where the superheat of the fluid is quenched before the turbine. A cycle with an additional turbine together with a cycle with heat recovery are the two alternative cycles utilizing wet scrubbing. The cycle with heat recovery performs best under every aspect as it is the one with the highest power output and the lowest unit cost of exergy of all cycles. Design and economic limitations of the other cycles also confirm the heat recovery cycle as being the most realistic one. On the contrary, the binary cycle resulted as the most expensive in unit cost of exergy and the base case cycle performed the worst in power output. In total, this work provides an idea of the path to follow in designing a geothermal power plant by accomplishing a component by component thermoeconomic analysis and combining the factors used to obtain the optimal cycle design.

This paper presents a thermoeconomic analysis of a trigeneration system interacting with the economic environment. The aim is to determine the energy and total costs of internal flows and final energy services (electricity, cooling and heat). One of the main difficulties in calculating these costs in trigeneration plants within buildings is the continuous variation of energy supply services. Fuel prices and purchase/sale electricity tariffs can also vary. As a consequence there are different operation conditions that combine the possibilities of purchasing or selling electricity, consuming heat from auxiliary boilers, and wasting the excess of cogenerated heat. A novel cost allocation method valid for all possible operation conditions of the trigeneration system is proposed. The heat produced by cogeneration modules is disaggregated into three fractions: heat that meets the heat demand directly, heat utilized to drive absorption chillers (producing cooling), and heat dissipated to the environment. Cost allocation to all cogeneration co-products is determined by applying the principle of avoided expenditures. The cost allocation proposal is applied to a trigeneration system providing energy services to a hospital with 500 beds located in Zaragoza (Spain), encouraging rational and efficient energy services production and consumption.► Thermoeconomic analysis of a trigeneration system operating at variable load conditions. ► The heat cogenerated is disaggregated into three fractions. ► Costs are allocated by applying the principle of avoided expenditures. ► Energy and total costs of electricity, heat and cooling are calculated. ► The proposal encourages rational and efficient operation of the system.

As a direct result of economic pressures to cut expenses, as well as the legal obligation to reduce emissions, companies and businesses are seeking ways to use energy more efficiently. Trigeneration systems (CHCP: Combined Heating, Cooling and Power generation) allow greater operational flexibility at sites with a variable demand for energy in the form of heating and cooling. This is particularly relevant in buildings where the need for heating is restricted to a few winter months. In summer, the absorption chillers make use of the cogenerated heat to produce chilled water, avoiding waste heat discharge. The operation of a simple trigeneration system is analyzed in this paper. The system is interconnected to the electric utility grid, both to receive electricity and to deliver surplus electricity. For any given demand required by the users, a great number of operating conditions are possible. A linear programming model provides the operational mode with the lowest variable cost. A thermoeconomic analysis, based on marginal production costs, is used to obtain unit costs for internal energy flows and final products as well as to explain the best operational strategy as a function of the demand for energy services and the prices of the resources consumed.

In the current and forecasted energy scenario, Natural Gas Combined Cycle (NGCC) power plants are requested increasingly flexible operation. The continuous changes in the capacity factor of the power plants and the increasing number and steepness of ramp-ups could largely affect the thermodynamic and economic performance of the plants and undermine their competitiveness.
In order for industrial operators to adopt competitive strategies to increase the flexibility of the power plants, the effect that off-design operation has on the cost structure of plant products needs to be addressed. Thermoeconomics provides tools and models to meet such objective.
The study presents an application of Thermoeconomic Input-Output Analysis (TIOA) to a NGCC power plant subject to flexible operation in Italy. The on- and off-design performance of the plant is assessed, considering two load control mechanisms for off-design operation: Inlet Guide Vanes (IGVs) with constant Turbine Outlet Temperature (TOT) or constant Turbine Inlet Temperature (TIT). The Input-Output model is derived from a detailed off-design Thermodynamic model designed in Thermoflow Thermoflex™, and it is stand-alone: it computes the cost structure of the plant products and the Thermoeconomic performance indicators as continuous functions of the gas turbine load, independently from the Thermodynamic model.
In the first place, the on- and off-design models of the plant are set up. Secondly, the detailed economic cost analysis is performed. Eventually, the stand-alone Input -Output model is derived: the Technical Coefficients and the Input Coefficients are computed from the fuels and products in the Thermodynamic model at different loads; by regression of the obtained values, continuous functions of the load are derived for each coefficient; finally, the stand-alone model is designed, including these functions in the Leontief Inverse matrix.
The results provide an evaluation of the off-design performance of the power plant for the two control strategies, and a tool for the choice of the most efficient one. After specialised analysts set up and run the off-design Thermodynamic model, the power plant operators may perform production scenarios and predictions through the stand-alone Input-Output model independently. This may help abate barriers for industrial practitioners, given by the complexity, computational effort and difficult interpretation of off-design thermodynamic and cost models.

ABSTRACT Natural non-renewable resources, such as minerals, are becoming increasingly depleted against a backdrop of intense industrialisation. Through the exergy analysis and thermoeconomic tools it is possible to assign a figure to the degree of depletion. This is because the exergy replacement cost represents the effort needed by humankind to return minerals to their original conditions from the “commercially dead state”, Thanatia. The authors undertake an evaluation of the ten most significantly produced minerals in Colombia, since 1990. Via the 2011 mineral balance, this paper shows that the highest exergetic losses are in the extraction for export and not national consumption rates. The loss in mineral wealth, quantified in exergy terms for 2011 is 119.2 Mtoe (4.99×109 GJ) and has, since 1990, accumulated to 1,543.4 Mtoe (6.46×1010 GJ). In converting these losses into economic terms, it becomes clear that the nation must re-think its mineral export strategy, if it is develop sustainably.

This paper presents sensitivity and resilience analyses for a trigeneration system designed for a hospital. The following information is utilized to formulate an integer linear programming model: (1) energy service demands of the hospital, (2) technical and economical characteristics of the potential technologies for installation, (3) prices of the available utilities interchanged, and (4) financial parameters of the project. The solution of the model, minimizing the annual total cost, provides the optimal configuration of the system (technologies installed and number of pieces of equipment) and the optimal operation mode (operational load of equipment, interchange of utilities with the environment, convenience of wasting cogenerated heat, etc.) at each temporal interval defining the demand. The broad range of technical, economic, and institutional uncertainties throughout the life cycle of energy supply systems for buildings makes it necessary to delve more deeply into the fundamen...

Environmental concerns have been a growing issue when planning energy supply systems for buildings, as the energy demands (presenting seasonal and daily variations) represent one of the most energy-intensive consumptions in industrialized societies. The optimal operation mode of a trigeneration system corresponding to several demands was obtained from the solution of a linear programming model. Surplus electricity can be sold to the national grid and part of the cogenerated heat can be wasted if this results in a decrease of operation costs and/or environmental loads. Thermoeconomic analysis, usually used to allocate energy and economic costs, is applied to the
evaluation of environmental costs and the distribution of resources throughout the trigeneration system. Attention is focused on the correct allocation of the energy resources consumed (evaluated at market prices) and of the environmental loads involved in the operation of the trigeneration system (applying Life Cycle Analysis) to internal flows and final products. Appropriate rules are given to calculate energy and environmental costs. The allocation method proposed is congruent
with the objectives of installing trigeneration systems that supply energy services with fewer emissions than those of separate production, and of equally benefitting the consumers of heat,
cooling and electricity.

The Factom team recently enshrined the records of the entire Gutenburg Library in two hashes. As the preliminary tests showed proof of concept, further potential uses have been highlighted to show where hundreds of billions of dollars can be saved, and hundreds of billions gained from securing property with an indisputable record. The potential for anti-fraud tracking, smart-contract advancement, and ethical decision making for AI are just a few areas in which the Factom team believes they can change the world for the better.

The aim of this work is to develop a method for optimization of operating parameters
of a triple pressure heat recovery steam generator. Two types of optimization:
(a) thermodynamic and (b) thermoeconomic were performed. The purpose of the
thermodynamic optimization is to maximize the efficiency of the plant. The selected
objective for this purpose is minimization of the exergy destruction in the heat recovery
steam generator. The purpose of the thermoeconomic optimization is to decrease
the production cost of electricity. Here, the total annual cost of heat recovery
steam generator, defined as a sum of annual values of the capital costs and the
cost of the exergy destruction, is selected as the objective function. The optimal values
of the most influencing variables are obtained by minimizing the objective function
while satisfying a group of constraints. The optimization algorithm is developed
and tested on a case of combined cycle gas turbine plant with complex
configuration. Six operating parameters were subject of optimization: pressures
and pinch point temperatures of every three (high, intermediate, and low pressure)
steam stream. The influence of these variables on the objective function and production
cost are investigated in detail. The differences between results of thermodynamic
and the thermoeconomic optimization are discussed.