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The exergy analysis method was applied in order to evaluate the new combined cycle proposed by Goswami [Solar thermal technology: present status and ideas for the future. Energy Sources 1998;20:137–45], using Hasan–Goswami–Vijayaraghavan parameters. This new combined cycle was proposed to produce both power and cooling simultaneously with only one heat source and using ammonia–water mixture as the...
We prepared energy and carbon balances for 68 petrochemical processes in the petrochemical industry for Western Europe, the Netherlands and the world. We analysed the process energy use in relation to the heat effects of the chemical reactions and quantified in this way the sum of all energy inputs into the processes that do not end up in the useful products of the process, but are lost as waste heat...
A scale of 2.4MW molten carbonate fuel cell (MCFC) was taken to construct a high-efficiency and economic power generation system without CO 2 emission for utilizing its exhaust gas. A conventional steam turbine power generation system (STPS) is evaluated and the net generated power (NGP) is estimated to be only 131kW and the STPS is not economically feasible. A CO 2 -caputuring repowering...
In this paper, a computational study of the influence of the heat exchangers' thermal resistances (in both the hot and cold side) on the efficiency of a thermoelectric generation device has been carried out.For this purpose, a computational model has been developed. This model uses the numerical method of finite differences to simulate the performance of the thermoelectric generation system, including...
Over two-thirds energy of fuel consumed by an automobile is discharged to the surroundings as waste heat. The fuel usage can be more efficient if thermoelectric generators (TEG) are used to convert heat energy into electricity. In this study, a thermoelectric module composed of thermoelectric generators and a cooling system is developed to improve the efficiency of an IC engine. Two potential positions...
Evidence on global climate change, being caused primarily by rising levels of greenhouse gases in the atmosphere, is perceived as fairly conclusive. It is generally attributed to the enhanced greenhouse effect, resulting from higher levels of trapped heat radiation by increasing atmospheric concentrations of gases such as CO 2 (carbon dioxide). Much of these gases originate from power plants...
The study introduced a novel thermally activated cooling concept – a combined cycle couples an ORC (organic Rankine cycle) and a VCC (vapor compression cycle). A brief comparison with other thermally activated cooling technologies was conducted. The cycle can use renewable energy sources such as solar, geothermal and waste heat, to generate cooling and power if needed. A systematic design study was...
The main results of a theoretical work on the use of a low temperature heat source for power generation through a carbon dioxide transcritical power cycle are reported in this paper. The procedure for analyzing the behaviour of the proposed cycle consisted in modifying the input pressure to the turbine from 66 bar, maintained constant each evaluated temperature (60 °C, 90 °C, 120 °C and 150 °C) until...
Molten slags represent one of the largest untapped energy sources in metal manufacturing operations. The waste heat of slags amounting to ∼220 TWh/year at temperatures in the range of 1200–1600 °C, presents an opportunity to lower the energy intensity of metal production. Currently, three types of technologies are under development for utilizing the thermal energy of slags; recovery as hot air or...
Two-thirds of input energy for electricity generation in the USA is lost as heat during conversion processes. Additionally, 12.5% of primary fuel and 20.3% of electricity are employed for space heating, water heating, and refrigeration where low-grade heat could suffice. The potential for harnessing waste heat from power generation and thermal processes to perform such tasks is assessed. By matching...
The Organic Flash Cycle (OFC) is proposed as a vapor power cycle that could potentially improve the efficiency with which high and intermediate temperature finite thermal sources are utilized. The OFC's aim is to improve temperature matching and reduce exergy losses during heat addition. A theoretical investigation is conducted using high accuracy equations of state such as BACKONE, Span–Wagner, and...
The previously proposed Organic Flash Cycle (OFC) was shown to potentially improve power generation from finite thermal energy reservoirs. The OFC's primary advantage was improved temperature matching to the energy reservoir, thereby reducing exergy destruction and losses during energy transfer to the cycle working fluid. This advantage was negated though by irreversibilities introduced by flash evaporation...
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...
The pulse tube engine is a simple heat engine based on the pulse tube process. Due to its simplicity it has a high potential to be applicable in waste heat usage and energy harvesting purposes. In this work, mathematical and experimental design tools are developed to study a pressurized laboratory scale pulse tube engine. The mathematical model is based on the transient numerical solution of the governing...
The introduction of CO 2 removal processes causes usually generation of waste heat. As the temperature of waste heat carriers is usually moderately high (ca. 100 °C), there is a potential possibility for using them in district heating systems. The main goal of present paper is thus the energy and CO 2 emission analysis of CHP (combined heat and power production) plants equipped with...
Adsorption chillers are capable of utilizing inexpensive or free low grade thermal energy such as waste heat and concentrated solar thermal energy. Recently developed low regeneration temperature working pairs allow adsorption chillers to be driven by even lower temperature sources such as engine coolant and flat plate solar collectors. In this work, synthetic zeolite/water was implemented into a...
The pulse tube engine represents the thermodynamic inversion of the pulse tube refrigerator used in cryogenic cooling applications. It has a high potential to be used as a prime mover for the conversion of low grade waste heat into mechanical or electrical energy. This paper describes an analytical analysis of the pulse tube engine based on a zero-dimensional model. During compression and expansion,...
The biggest technical barrier to full scale deployment of absorption technology for post-combustion carbon capture in electric power plants is the high energy consumption for solvent regeneration. This paper presents a new application of ejectors to upgrade external waste heat for the purpose of reducing the amount of valuable turbine steam that is required to supply the solvent regeneration process...
An additional high pressure economizer was installed at Unit B1 of the 620 MWe lignite-fired Power Plant “Nikola Tesla B” after 30 years of its operation. An innovative connection of the new additional economizer was applied. It is in parallel connection to the first section of the originally built economizer and it is directly fed with the feedwater from the outlet of the feedwater pump. The analysis...
In this study, the potential for waste heat recovery is examined based on real data from 1990 to 2011 (a 21-year period) for processes at low-, medium- and high-temperature levels. The first part of this study included a theoretical analysis for determining the potential for heat recovery at these temperature stages. Second part stated an application in the industrial sector. This study is conducted...
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