Thermoeconomic Optimization Analysis Research Articles

Ammonia heat pumps for district heating: thermo-economic optimization analysis based on evaporator geometry for either direct expansion or chilled water configurations

Electric heat pumps are recognized as a key technology for decarbonization and have received increasing policy support in several countries over the last few years. These devices offer a highly efficient form of electric heating and could make an important contribution to the transition to a low carbon future, especially in case of district heating systems. Within this context, this paper presents a thermo-economic optimization analysis of a 7.35 MW electric heat pump system employed for district heating purposes and using ammonia as working fluid. The implemented code gathers multiple sub-models calibrated ad-hoc from real data or manufacturers’ datasheets. The heat exchangers are simulated by considering phenomenological equations and well-known heat transfer coefficient and pressure drop prediction methods. The optimization analysis is performed at constant condensation temperature that guarantees in/out hot water temperatures of 30/62 °C and is focused on the matching between compressor and evaporator heat exchanger, by considering either a direct expansion system or a chilled water heat pump. Both the coefficient of performance (COP) and the set-up costs are considered as optimization performance indicators for the construction of the Pareto front.

Thermo-economic optimization of a 100 kW air-to-water heat pump for heating purposes in residential units

In order to reach the ambitious objectives of carbon neutrality by 2050 and the limitation of the ambient temperature rise at 1.5 °C, several intensive energy fields such as heating and cooling appliances should be decarbonized. On this regard, electric heat pumps represent the most promising solutions to replace old and inefficient conventional boilers and comply with the ecological transition through the increase of electric energy production by means of renewable sources. In this paper, a thermo-economic optimization analysis of a 100 kW air-to-water electric heat pump is proposed. The appliance is designed to produce hot water at 55 °C. The developed model employs phenomenological equations calibrated on real data and manufacturer datasheets for compressor, heat exchangers, and costs. Different design options, including the heat exchangers size and the choice of the working fluid (among R32, propane R290, ammonia R717, R454C), are presented and discussed. The Pareto analysis is then employed to find the best possible configurations in terms of costs and performance.

Optimal efficiencies of an isothermal endoreversible chemical engine

In the context of finite-time thermodynamics, an instructive study of the thermodynamic and thermoeconomic optimization analysis of Novikov engine models is presented. The so-called objective functions of the maximum power, ecological and efficient power regimes of operation are introduced. The study addresses the optimization methodology to obtain the efficiencies that maximize the various functions. An isothermal chemical engine is used as an analogy to Novikov’s engine to demonstrate the physical and mathematical procedures. Didactically, new results are presented through expanding prior research.

A comparative thermodynamic and thermoeconomic analysis between two ecological regimes for the Novikov energy converter

In the context of finite-time thermodynamics, a comparative thermodynamic analysis between the ecological regime and the ecological efficient power regime, recently introduced, is done. The study examines the Novikov energy converter model with a linear heat transfer law when performing under these regimes. To make the proper comparison, through the so-called compromise functions, a modification to the ecological efficient power energetic function is proposed. It is found that the thermal efficiencies are very similar to the appropriate ones of the modified ecological function. However, notable differences are obtained for the optimal efficiencies from a thermoeconomic optimization analysis.

Güneş Sıcak Su Isıtma Sistemleri için Termo Ekonomik Optimizasyon Üzerine Bir Çalışma

A thermo economic optimization analysis is presented based on steady state performance at annual average condition which yields simple algebraic formula for estimating the optimum heat storage tank capacity for solar energy applications. The P1-P2 method is used in the present study, together with the most favorable heat storage tank dimensioning criteria, for thermo economic analysis of solar hot water heating systems, SHW, including costs of all system elements. The optimum storage capacity and the most feasible collector area are calculated at which maximum net life cycle savings occurs for solar hot water heating systems. The validity of the optimization formulation was checked.

Simulation and optimization of steam operated double effect water-LiBr absorption heat pump

The absorption heat pump technology plays an invaluable role in energy structure optimization and sustainable development. In this research, the steam operated double effect water-LiBr absorption heat pump is introduced and the performance is studied at nominal and part load conditions. Mathematical models are developed and verified by experiments, and the results indicate that the maximum deviation is about 13% at heating condition and 9% at cooling condition. An optimization analysis is presented with mathematical models to optimize the absorption heat pump. The optimal combination of multi-factorial internal parameters, which are the eight main heat transfer temperature differences, are obtained from the thermoeconomic optimization analysis. The results will be much helpful in the design and optimization of double effect water-LiBr absorption heat pumps.

Comparative evaluation of sizing of metal hydride (MH) hydrogen storage tank filled with different alloys

ABSTRACTThis study presents a comparative analysis of sizing of metal hydride tank filled with different alloys. Alloys include solid solutions and intermetallic compounds of the generic families AB5, AB2, AB, A2B. The effects of the different alloys on the sizing of metal hydride hydrogen storage tanks are complicated and depend on many factors. In this paper, a thermoeconomic optimization analysis with a simple algebraic formula was presented for the estimation of optimum metal hydride tank surface area for heat transfer enhancement. The optimum area of the metal hydride tank filled with commercially available different alloys (LaN5, Ti0,98Zr0,02V0,43Fe0,09Cr0,05Mn1,5, TiFe, Mg2NiH4) was evaluated and compared by the developed method. The optimum net savings and the value of payback were determined for four alloys. It is found that mathematical model can be employed for the determination of optimum metal hydride tank design and increasing net savings according to alloy types. The optimum areas of the tanks filled with four alloys (LaN5, Ti0,98Zr0,02V0,43Fe0,09Cr0,05Mn1,5, TiFe, Mg2NiH4) were calculated as 0.136, 0.130, 0.133, and 0.173 m2, respectively. The optimum net savings for tanks filled with four alloys (LaN5, Ti0,98Zr0,02V0,43Fe0,09Cr0,05Mn1,5, TiFe, Mg2NiH4) are about 461.0, 409.3, 419.6, and 979.6 $ and the values of payback are about 1.98, 2.1, 2.17, and 1.37 years, respectively. Excessive area of the metal hydride tank would not be as economical as the optimum tank area. Thermal management of metal hydride tank must be designed for optimum points calculated at which maximum savings occur.

On the optimum sizing of metal hydride tank filled AB2 type alloy

When the metal hydride tanks that are used in hydrogen storage are thermally coupled to the fuel cell, thermal management of metal hydride tank is to get importance in the development of the fuel cell performance. Heat transfer has been shown to be the rate limiting process controlling hydrogen uptake or removal. Discharge capacity of the tank has a major impact on the fuel cell efficiency. In this paper, a thermoeconomic optimization analysis is presented yielding a simple algebraic formula for estimating optimum metal hydride tank surface area for heat transfer enhancement. A simple economic method is used in the study, together with thermal analysis. The optimum area of the metal hydride tank filled with commercially available AB2 type alloy (Ti0,98Zr0,02V0,43Fe0,09Cr0,05Mn1,5) is calculated by this method as 0.16 m2. The optimum net savings is about 902.7$ and the value of payback is determined as 1.3 years. Excessive area of the metal hydride tank will not be economical as the optimum tank area.

Thermoeconomical Optimization of Number of Panes for Windows

This paper presents a thermoeconomic optimization analysis yielding a simple algebraic formula for estimating the optimum number of panes for windows. The “ P1 - P2 method,” “the degree day method,” and “the equivalent full load hours energy estimation method” are used together with the correlated overall heat transfer coefficient values for single, double, triple, and quadruple pane windows that are used in HVAC and refrigeration applications.

A thermo-economical optimization of a domestic solar heating plant with seasonal storage

In this study, the thermo-economic optimization analysis to determinate economically optimal dimensions of collector area and storage volume in domestic solar heating systems with seasonal storage is presented. For this purpose, a formulation based on the simplified P 1 and P 2 method is developed and solved by using MATLAB optimization Toolbox for five climatically different locations of Turkey. The results showed that the required optimum collector area in Adana (37 °N) for reaching maximum savings is 36 m 2/house and 65 m 2/house in Erzurum (39 °N) for same storage volume (1000 m 3). The effects of collector efficiency on solar fraction and savings are investigated. The simulation results showed that the solar fraction and savings of the selective flat plate collector systems are higher than the other black paint flat plate collector systems.

Operational cost minimization of heat pump for milk pasteurization in dairy

A thermo economic optimization analysis is presented yielding simple algebraic formula for estimating the optimum operating conditions of interconnected heat pump assisted milk pasteurizing systems. The overall operational cost method including the cost of auxiliary heater is used in the present study, together with the thermal analyses of all system components, for thermo economic analysis of the system.

Optimum heat pump in milk pasteurizing for dairy

A thermo economic optimization analysis is presented yielding simple algebraic formula for estimating the optimum operating conditions of interconnected heat pump-refrigeration systems with auxiliary heating that are used in milk pasteurizing applications. A simple economic method is used in the present study, together with the thermal analyses of all system components, for thermo economic analysis of the system.

Optimum heat pump in drying systems with waste heat recovery

A thermo economic optimization analysis is presented yielding simple algebraic formula for estimating the optimum operating conditions of heat pump with auxiliary heating that are used in drying applications. A simple economic analysis method is used in the present study, together with the thermal analyses of all system components, for thermo economic analysis of the system.

Optimum insulation-thickness for thermal and freezing protection

Methods for protecting water pipes, in cold regions against freezing, by thermal insulation material and heating cable will be analyzed. Reliability of keeping the tube's wall temperature of a piping system at minimum value will be analyzed. A thermoeconomic optimization analysis is applied with a simple algebraic formula derived for estimating the optimum insulation thickness for tubes of different sizes. The optimization is based on a life-cycle cost analysis. The effects of design parameters on the optimum thickness are investigated. Predicted results of this study would provide useful reference data when considering design, practical operation or maintenance.

On the thermo economical optimization of single stage refrigeration systems

In this work, a thermo economic optimization analysis is presented yielding a simple algebraic formula for estimating the optimum operating temperature for refrigeration systems, which utilizes energy recovery applications. The method used is known as the P 1– P 2 method, used with the usage factor and simplified wall gain load factors.

On the thermoeconomical optimization of heat pipe heat exchanger HPHE for waste heat recovery

A thermoeconomic optimization analysis is presented yielding a simple algebraic formula for estimating the optimum HPHE effectiveness for energy recovery applications. The P 1– P 2 method is used in the present study, together with the ε–NTU method, for thermoeconomic analysis of a heat pipe heat exchanger, HPHE, of a noncondensing fluid type, i.e. employing water and air.

On the thermoeconomical optimization of fin sizing for waste heat recovery

A thermoeconomic optimization analysis is presented yielding simple algebraic formulae for estimating the optimum fin dimensions for energy recovery applications. The P 1− P 2 method is used in the present study, together with the most favorable fin dimensioning criteria, for thermoeconomic analyses of two different fin types, i.e. plate fin and pin fin.

Performance analysis of an endoreversible heat engine based on a new thermoeconomic optimization criterion

A new kind of finite time thermoeconomic optimization analysis for an endoreversible heat engine has been performed. The objective function has been taken as the power output per unit total cost. The optimum performance parameters that maximize the objective function are investigated. In this perspective, some analytical equations for the optimum working fluid temperatures, optimum thermal efficiency, optimal distributions of heat exchanger areas and optimum specific power output were found in terms of economical and technical parameters. The effects of the design parameters on the optimal conditions have been discussed.

On the optimum heat exchanger sizing for heat recovery

A thermoeconomic optimization analysis is presented yielding simple algebraic formulas for estimating the optimum heat exchanger area for energy recovery applications. The P 1– P 2 method is used in the present study, together with the well known Effectiveness–NTU method, for thermoeconomic analyses of three different unmixed type heat exchangers, i.e. countercurrent flow, parallel flow and single fluid or phase change.

Optimum insulation thickness for refrigeration applications

A thermoeconomic optimization analysis is presented yielding a simple algebraic formula for estimating optimum insulation thickness for refrigeration applications. The effects of design parameters on the optimum insulation thickness are investigated for three test cities using an interactive computer code written in Fortran 77. The equivalent full load hours method is used to estimate the energy requirements.