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In the paper conducted has been a concise survey of up to date investigations and simulations of the low-temperature Clausius–Rankine (C–R) cycle as well as presented have been authors own results of calculations regarding effectiveness of operation of the power station following such cycle. The power station is supplied with water being a carrier of geothermal or waste heat with temperature 80–115°C...
Nowadays, the use of Organic Rankine Cycle (ORC) in decentralised applications is linked with the fact that this process allows the use of low temperature heat sources and offers an advantageous efficiency in small-scale concepts. Many state-of-the-art and innovative applications can successfully use the ORC process. In this process, according to the heat source level, special attention must be drawn...
Heat activated cooling has the potential of utilizing thermal sources that currently go unused such as engine exhaust heat or industrial waste heat. Using these heat sources can provide enhanced energy utilization and reduced fuel usage in applications where cooling is needed. The concept developed here uses waste heat from stationary and mobile engine cycles to generate cooling for structures and...
A novel cryogenic cycle by using a binary mixture as working fluids and combined with a vapor absorption process was proposed to improve the energy recovery efficiency of an LNG (liquefied natural gas) cold power generation. The cycle was simulated with seawater as the heat source and LNG as the heat sink, and the optimization of the power generated per unit LNG was performed. Tetrafluoromethane (CF...
Optimisation of Organic Rankine Cycle (ORCs) for binary-cycle geothermal applications could play a major role in determining the competitiveness of low to moderate temperature geothermal resources. Part of this optimisation process is matching cycles to a given resource such that power output can be maximised. Two major and largely interrelated components of the cycle are the working fluid and the...
The concept studied in this work is a low power ORC–ORC heat pump system (providing about 20 kW heat at the condenser) and that is composed of an ORC power cycle driving a reversed ORC heat pump cycle, both cycles using the same fluid. The centrifugal compressor and the radial in-flow turbine are directly coupled on the same shaft rotating on self-acting refrigerant vapor bearings. The system has...
Waste heat recovery from the exhaust gases of gas turbines, geothermal resources, and from industrial plants offers a great opportunity for rational energy usage by productively converting the waste energy. In the present communication we report a systematic study starting with the hydrocarbons for the different temperature ranges at which the waste heat is available from high, medium, or low temperature...
The paper analyzes the combined TEG-ORC (thermoelectric generator and organic rankine cycle) used in exhaust heat recovery of ICE (internal combustion engine) theoretically. A theoretical model is proposed to calculate the optimal parameters of the bottoming cycle based on thermodynamic theory when net output power and volumetric expansion ratio are selected as objective functions, which affect system...
During the most recent years, among the different forms of renewable energy sources, biomass is playing an important role in the strategic agenda of European Community. Many countries, including Italy, have introduced important incentive schemes to support the use of biomass for electricity, heat and transportation. This has raised considerable interest towards the use of biomass for energy production...
The power enhancement potential of a mixture transcritical cycle was investigated by comparison between the power of an R134a subcritical cycle and that of binary HFC (hydrofluorocarbon) mixture transcritical cycles for a low-temperature geothermal heat source of about 100°C. To fairly compare the power of the cycles by using different working fluids, each cycle was optimized from the view point of...
With increasing cost for power generation opportunities for small scale power generation from waste heat have increased. The awareness of untapped resources such as local waste heat streams as well as the available range of technology and products to harvest such streams is increasing steadily though field data is scarce for applications below 100 °C entry temperature. ORC applications have a large...
An experimental system for heat recovery from low-temperature flue gas based on Organic Rankine Cycle (ORC) was constructed. In the system, R123 was selected as working fluid, a scroll expander was used to produce work, and fin tubes heat exchanger was designed as evaporator. Low-temperature flue gas produced by an liquefied petroleum gas (LPG) stove was used as the heat source to simulate industrial...
In a typical cement producing procedure, 25% of the total energy used is electricity and 75% is thermal energy. However, the process is characterized by significant heat losses mainly by the flue gases and the ambient air stream used for cooling down the clinker (about 35%–40% of the process heat loss). Approximately 26% of the heat input to the system is lost due to dust, clinker discharge, radiation...
A low-temperature heat driven heat engine is proposed as a cost-effective system for power and heat production for small scale applications. The external heat source allows flexibility in the design; the system may be coupled with various available renewable sources including biomass/biofuel/biogas combustion, geothermal heat, concentrated solar radiation, and industrial waste heat, by selecting appropriate...
An attempt is made in the present work to classify the energy sources that can drive the ORC (organic Rankine cycle) power plants. Concepts of the open and sealed type of the energy sources are introduced as well as the difference between the energy source capacity and the energy supplied to the power plant cycle is presented. By application of the exergy analysis it has been proved via examples of...
The ENERCO_LT (ENErgy ReCOvery from Low Temperature heat sources) project is a waste heat recovery project that aims to reduce energy consumption in industrial gas production sites by producing electricity through Organic Rankine Cycles supplied by exothermic process discharges at low and medium temperatures. Two promising thermal sources consisting of (i) almost dry gas flow at 165°C and (ii) moist...
This article presents a methodology to help in the definition of the optimal design of power generation systems. The innovative element is the integration of requirements on dynamic performance into the system design procedure. Operational flexibility is an increasingly important specification of power systems for base- and part-load operation. Thus, it is crucial to discard, in an early phase of...
Low-grade waste heat source accounts for a large part of the total industrial waste heat, which cannot be efficiently recovered. The ORC (Organic Rankine Cycle) system has been proved to be a promising solution for the utilization of low-grade heat sources. It is evident that there might be several waste heat sources distributing in different temperature levels in one industry unit, and the entire...
The comparison is made between various turbine loss models from the point of view of small, highly loaded impulse turbines operating in ORC cycles. The focus is laid on the influence of the passage and partial admission loss models and their combinations. The paper discusses the limitations concerning the small turbine designs for ORC and takes them into account in the analysis. A case study is provided...
The purpose of the present paper is to propose a methodology for the fluid selection of an Organic Rankine Cycle for low-temperature waste heat recovery. The selection of an optimal working fluid is carried out by an optimization process, using the Genetic Algorithm. Three decision variables are considered: the working fluid, the evaporation temperature and the condensation temperature. These variables...
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