Feasibility study for recovering waste heat in reduction system of Kroll process: Energy analysis and economic valuation

An adsorption system driven by solar heat or waste heat can help to eliminate the use of ozone depletion substances, such as chlorofluorocarbons (CFCs) and hydro-chlorofluorocarbons (HCFCs). In recent years, adsorption system has witnessed an increasing interest in many fields due to the fact that this system is quiet, long lasting, cheap to maintain and environmentally benign. Although adsorption system is not commonly used for automobile air conditioning, adsorption-cooled mini-refrigerators have been marketed for recreational transports (motor homes, boats, etc). Hence, there exists a need for a creative design and innovation to allow adsorption technology to be practical for air conditioning in automobile. The objective of this paper is to present a comprehensive review on the past efforts in the field of solar adsorption refrigeration systems and also the feasibility study of this technology for automobile airconditioning purpose. It is a particularly an attractive application for solar energy because of the near coincidence of peak cooling loads with the available of solar power.

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Energy and Exergy Waste Heat Recovery Analysis of a Bulk Carrier Main Diesel Engine Equipped with Dual-Loop Organic Rankine Cycle

10.5957/some-2021-019 ◽

2021 ◽

Author(s):

Elias A. Yfantis ◽

Efthymios G. Pariotis ◽

Theodoros C. Zannis ◽

Konstantina Asimakopoulou

Keyword(s):

Diesel Engine ◽

Energy Analysis ◽

Waste Heat ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Ambient Conditions ◽

Bulk Carrier ◽

Operational Profile ◽

Exhaust Heat ◽

Marine Diesel

The energy and the exergy performance of a dual-loop Organic Rankine Cycle (ORC), which harvests exhaust heat from a two-stroke slow-speed main marine diesel engine of a bulk carrier is examined herein. An energy analysis is adopted to calculate the energy flows to the components of the high-temperature (HT) and the low-temperature (LT) loops of the bottoming ORC and through them, to calculate the energy efficiency of the ORC and the generated power from both expanders. Also, an exergy analysis is implemented to predict the irreversibility rates of the components of both HT and LT loops of the ORC system. Various organic fluids are examined for the HT and the LT ORC loops and the optimum combination is selected based on the results of a parametric analysis. The effect of ambient conditions on the energetic and exergetic performance of the dual-loop ORC is examined. The energy analysis of the bottoming dual-loop ORC is projected to a specific mission operational profile of a bulk carrier for predicting the benefits in fuel cost saving and CO2 and SO2 emission reduction compared to conventional vessel operation.

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Energy Analysis and Economic Valuation *

Green Accounting ◽

10.4324/9781315197715-4 ◽

2018 ◽

pp. 75-110 ◽

Cited By ~ 1

Author(s):

Nicholas Georgescu-Roegen

Keyword(s):

Energy Analysis ◽

Economic Valuation

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Energy-Saving Strategies and their Energy Analysis and Exergy Analysis for In Situ Thermal Remediation System of Polluted-Soil

Energies ◽

10.3390/en12204018 ◽

2019 ◽

Vol 12 (20) ◽

pp. 4018 ◽

Cited By ~ 1

Author(s):

Tian-Tian Li ◽

Yun-Ze Li ◽

Zhuang-Zhuang Zhai ◽

En-Hui Li ◽

Tong Li

Keyword(s):

Energy Saving ◽

Exergy Analysis ◽

Energy Analysis ◽

Waste Heat ◽

Polluted Soil ◽

Severe Problem ◽

Industrial Soil ◽

Thermal Remediation ◽

Variable Condition

The environmental safety of soil has become a severe problem in China with the boost of industrialization. Polluted-soil thermal remediation is a kind of suitable remediation technology for large-scale heavily contaminated industrial soil, with the advantages of being usable in off-grid areas and with a high fuel to energy conversion rate. Research on energy-saving strategies is beneficial for resource utilization. Focused on energy saving and efficiency promotion of polluted-soil in situ thermal remediation system, this paper presents three energy-saving strategies: Variable-condition mode (VCM), heat-returning mode (HRM) and air-preheating mode (APM). The energy analysis based on the first law of thermodynamics and exergy analysis based on the second law of thermodynamics are completed. By comparing the results, the most effective part of the energy-saving strategy for variable-condition mode is that high savings in the amount of natural gas (NG) used can be achieved, from 0.1124 to 0.0299 kg·s−1 in the first stage. Energy-saving strategies for heat-returning mode and air-preheating mode have higher utilization ratios than the basic method (BM) for the reason they make full use of waste heat. As a whole, a combination of energy-saving strategies can improve the fuel savings and energy efficiency at the same time.

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