The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
The conventional two-step thermal processing of phosphoric acid wastes enormous amounts of energy, which causes serious environmental pollution in addition to bad economic performance. A two-step waste heat recovery method using a “phosphorus burning boiler” was developed to reduce energy loss. This paper presents an exergy analysis model based on two new indicators for the “process driving force”...
A new combined power and ejector–absorption refrigeration cycle is proposed, which combines the Rankine cycle and the ejector–absorption refrigeration cycle, and could produce both power output and refrigeration output simultaneously. This combined cycle, which originates from the cycle proposed by authors previously, introduces an ejector between the rectifier and the condenser, and provides a performance...
The process integration of the bioprocess plant for production of yeast and alcohol was studied. Preliminary energy audit of the plant identified the huge amount of thermal losses, caused by waste heat in exhausted process streams, and reviled the great potential for energy efficiency improvement by heat recovery system. Research roadmap, based on process integration approach, is divided on six phases,...
Typically, a great deal of heat is wasted in the drainage systems of large-scale public shower facilities, such as those in schools, barracks, and natatoriums. This paper enhances a heat pump system used in public shower facilities for exhaust heat recovery. The system consists of three sections for exhaust heat recovery: solar energy collection system, drainage collection system, and heat pump system...
Exergy change rate in an ideal gas flow or an incompressible flow can be divided into a thermal exergy change rate and a mechanical exergy loss rate. The mechanical exergy loss rates in the two flows were generalized using a pressure-drop factor. For heat exchangers using in waste heat recovery, the consumed mechanical exergy is usually more valuable than the recovered thermal exergy. A weighing factor...
This paper examines the exhaust waste heat recovery potential of a high-efficiency, low-emissions dual fuel low temperature combustion engine using an Organic Rankine Cycle (ORC). Potential improvements in fuel conversion efficiency (FCE) and specific emissions (NO x and CO 2 ) with hot exhaust gas recirculation (EGR) and ORC turbocompounding were quantified over a range of injection...
Parametric optimization and performance analysis of a waste heat recovery system based on Organic Rankine Cycle, using R-12, R-123 and R-134a as working fluids for power generation have been studied. The cycles are compared with heat source as waste heat of flue gas at 140 °C and 312 Kg/s/unit mass flow rate at the exhaust of ID fans for 4 × 210 MW, NTPC Ltd. Kahalgaon, India. Optimization of turbine...
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...
This paper proposes a new pumpless Rankine-type cycle for power generation from low-temperature heat sources. The new cycle mainly consists of an expander, two heat exchangers, and switching valves for the expander and heat exchangers. Instead of using a working fluid pump, the switching valves method (SVM) is employed to control the cycle. The SVM makes each heat exchanger switch between functioning...
Organic Rankine Cycle (ORC) could be used to recover low-grade waste heat. When a vehicle is running, the engine exhaust gas states have a wide range of variance. Defining the operational conditions of the ORC that achieve the maximum utilization of waste heat is important. In this paper the performance of different working fluids operating in specific regions was analyzed using a thermodynamic model...
Significant energy efficiency gains in zones with concentrated activity from energy intensive industries can often be achieved by recovering and reusing waste heat between processing plants. We present a systematic approach to target waste heat recovery potentials and design optimal reuse options across plants in industrial zones. The approach first establishes available waste heat qualities and reuse...
Thermally activated systems based on sorption cycles, as well as mechanical systems based on vapor compression/expansion are assessed in this study for waste heat recovery applications. In particular, ammonia-water sorption cycles for cooling and mechanical work recovery, a heat transformer using lithium bromide-water as the working fluid pair to yield high temperature heat, and organic Rankine cycles...
The recent development to control the emissions of large diesel engines has provided opportunities for heat-driven cooling methods in vehicles. An adsorption air conditioning system is therefore proposed in this work for heavy-duty truck application. This system is powered by engine waste heat when the engine of a truck is running. When the engine is off, it can be operated by fuel fired heaters,...
This paper presents and studies the novel concept of thermoelectric self cooling, which can be introduced as the cooling and temperature control of a device using thermoelectric technology without electricity consumption.For this study, it is designed a device endowed with an internal heat source. Subsequently, a commonly used cooling system is attached to the device and the thermal performance is...
In this paper, we present a steady-state experiment, energy balance and exergy analysis of exhaust gas in order to improve the recovery of the waste heat of an internal combustion engine (ICE). Considering the different characteristics of the waste heat of exhaust gas, cooling water, and lubricant, a combined thermodynamic cycle for waste heat recovery of ICE is proposed. This combined thermodynamic...
A theoretical formula is proposed to calculate the OET (optimal evaporation temperature) of subcritical ORC (organic Rankine cycle) based on thermodynamic theory when the net power output is selected as the objective function. The OETs of 22 working fluids including wet, isentropic and dry fluids are determined under the given conditions. In order to compare the accuracy of these results, the quadratic...
The industrial waste heat parameters, like flow rate and temperature, usually fluctuate in a certain range due to the variation of upstream industrial process. However, the heat recovery systems are usually designed not under the fluctuation range but under a specific point, therefore, the most reasonable design condition of the waste heat should be estimated based on the fluctuation ranges. A single...
A large amount of low grade energy is often wasted without heat recovery in the process industry. Over-the-fence heat integration for district heating (DH) can be suggested to utilize this waste heat and therefore alleviate the carbon footprint of the integrated energy system. The economic performance of over-the-fence process integration depends on the cost of fuel, electricity and distance for the...
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...
The ever-increasing restrictions on greenhouse gas emissions have created a need for new energy technologies. One way to meet these new requirements is to optimise the efficiency of power units. This paper presents two energy technologies that, if used, will increase the efficiency of electricity generation. One of the most effective ways to improve the efficiency of brown coal-fired units is by drying...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.