Although the cost allocation method does not change the total benefits of CHP, the use of various cost allocation methods generally results in significant differences in costs allocated for CHP products. In order to overcome the inadequacy of existing cost allocating methods in theory and in practice, according to the different roles of anergy and exergy in heat supply process of CHP plant, the...

This study presents comparative energy and exergy analyses of a single cylinder, four stroke Ruston diesel engine. The test was conducted by varying the load between zero and maximum while keeping the engine speed constant. Then, using the steady-state data along with energy and exergy balance equations, various performance parameters of the engine were measured. From the study it was found tha...

The massive consumption of finite resources creates high economical and environmental costs due to material dispersion and waste generation. In order to overcome this, by-products and wastes may be used, to avoid the use of virgin materials and benefit from the useful inherent energy of the material. By adding value to the material, economic and environmental performance can be improve, which i...

The current method used for calculating societal aggregated exergy efficiencies is reviewed. Cooling is introduced as an end-use category; conversion efficiencies for heating processes are obtained for each energy carrier; and electricity shares per end-use are retrieved for each sector, improving the accuracy of the estimated values of aggregated exergy efficiencies. We show that: (1) cooling ...

The performance and design criteria of air powered multistage turbines are studied thermodynamically in this paper. In-house code is developed in the C++ environment and the characteristics of four-stage turbines with inter-heating are analyzed in terms of maximum thermal efficiency, maximum exergy efficiency and maximum work output over the inlet temperature range of 293 K–793 K with inlet pre...

The phrase ‘emergy baseline’ refers to the total yearly environmental support to the geobiosphere in terms of the emergy concept, and should include all three fundamental sources of exergy (i.e. sunlight, tidal exergy and deep earth heat). Ever since its introduction, the emergy baseline has undergone a continuous revision process, which, however, has so far focussed on the underlying equations...

The use of exergy to correlate energy-utilization efficiencies and energy research investments is described. Specifically, energy and exergy losses are compared with energy research and development expenditures, demonstrating that the latter correlates with energy losses, even though it would be more sensible to allocate energy research and development funding in line with exergy losses, as the...

Engineered geothermal systems (EGS) present an opportunity to expand the implementation of geothermal power. There has been some interest in the possible application of CO2 as a heat extraction fluid in these systems instead of water, due to a variety of inherent benefits, including being a nonpolar fluid, low viscosity at the temperatures and pressures within the reservoir and a large buoyancy...

Due to long life of steam power plants in Iran, transformation of steam cycles to combined cycles is under consideration. Bandar-Abbas steam power plant with capacity of 320 MW has been analyzed in this work. This old plant is located near the harbor city of Bandar-Abbas at southern Iran. Method of exergy analysis is used to study the current and the repowered systems. Optimum state of the repo...

Ecosystems are vital to any human activity because they constitute the basic planetary support systems. Their deterioration threatens the sustainability of all industrial activity and erodes a nation’s productive capital base. A necessary step towards preserving ecosystems is to estimate their contribution to economic activity. Most contemporary economic, thermodynamic and life cycle assessment...