Absorption chiller waste heat utilization to the desiccant dehumidifier system for enhanced cooling – Energy and exergy analysis

One way to increase overall natural gas engine efficiency is to transform exhaust waste heat into useful energy by means of a bottoming cycle. Organic Rankine cycle (ORC) is a promising technology to convert medium and low grade waste heat into mechanical power and electricity. This paper presents an energy and exergy analysis of three ORC-Waste heat recovery configurations by using an intermediate thermal oil circuit: Simple ORC (SORC), ORC with Recuperator (RORC) and ORC with Double Pressure (DORC), and Cyclohexane, Toluene and Acetone have been proposed as working fluids. An energy and exergy thermodynamic model is proposed to evaluate each configuration performance, while available exhaust thermal energy variation under different engine loads was determined through an experimentally validated mathematical model. Additionally, the effect of evaportating pressure on net power output , absolute thermal efficiency increase, absolute specific fuel consumption decrease, overall energy conversion efficiency, and component exergy destruction is also investigated. Results evidence an improvement in operational performance for heat recovery through RORC with Toluene at an evaporation pressure of 3.4 MPa, achieving 146.25 kW of net power output, 11.58% of overall conversion efficiency, 28.4% of ORC thermal efficiency, and an specific fuel consumption reduction of 7.67% at a 1482 rpm engine speed, a 120.2 L/min natural gas Flow, 1.784 lambda, and 1758.77 kW mechanical engine power.

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Energy and exergy analysis for waste heat cascade utilization in sinter cooling bed

Energy ◽

10.1016/j.energy.2013.11.086 ◽

2014 ◽

Vol 67 ◽

pp. 370-380 ◽

Cited By ~ 47

Author(s):

Yan Liu ◽

Jian Yang ◽

Jin Wang ◽

Zhi-long Cheng ◽

Qiu-wang Wang

Keyword(s):

Exergy Analysis ◽

Waste Heat ◽

Energy And Exergy ◽

Energy And Exergy Analysis

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Energy and Exergy Analysis of the S-CO2 Brayton Cycle Coupled with Bottoming Cycles

Processes ◽

10.3390/pr6090153 ◽

2018 ◽

Vol 6 (9) ◽

pp. 153 ◽

Cited By ~ 8

Author(s):

Muhammad Siddiqui ◽

Aqeel Taimoor ◽

Khalid Almitani

Keyword(s):

Heat Source ◽

Exergy Analysis ◽

Waste Heat ◽

Combined Cycle ◽

Cycle Performance ◽

Aspen Hysys ◽

Energy And Exergy ◽

Technological Developments ◽

Energy And Exergy Analysis ◽

Gas Turbine Exhaust

Supercritical carbon dioxide (S-CO2) Brayton cycles (BC) are soon to be a competitive and environment friendly power generation technology. Progressive technological developments in turbo-machineries and heat exchangers have boosted the idea of using S-CO2 in a closed-loop BC. This paper describes and discusses energy and exergy analysis of S-CO2 BC in cascade arrangement with a secondary cycle using CO2, R134a, ammonia, or argon as working fluids. Pressure drop in the cycle is considered, and its effect on the overall performance is investigated. No specific heat source is considered, thus any heat source capable of providing temperature in the range from 500 °C to 850 °C can be utilized, such as solar energy, gas turbine exhaust, nuclear waste heat, etc. The commercial software ‘Aspen HYSYS version 9’ (Aspen Technology, Inc., Bedford, MA, USA) is used for simulations. Comparisons with the literature and simulation results are discussed first for the standalone S-CO2 BC. Energy analysis is done for the combined cycle to inspect the parameters affecting the cycle performance. The second law efficiency is calculated, and exergy losses incurred in different components of the cycle are discussed.

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ENERGY AND EXERGY ANALYSIS OF COMPACT POWER GENERATION AND HYBRID SOLAR ENERGY-WASTE HEAT-BASED TRIPLE EFFECT EJECTOR-VAPOR ABSORPTION REFRIGERATION CYCLE

International Journal of Air-Conditioning and Refrigeration ◽

10.1142/s2010132513500235 ◽

2013 ◽

Vol 21 (04) ◽

pp. 1350023 ◽

Cited By ~ 5

Author(s):

RAJ KUMAR ◽

ANIL KUMAR

Keyword(s):

Power Generation ◽

Exergy Analysis ◽

Waste Heat ◽

Energy Output ◽

Refrigeration Cycle ◽

Absorption Refrigeration ◽

Energy And Exergy ◽

Energy And Exergy Analysis ◽

Exhaust Energy ◽

Vapor Absorption Refrigeration

An NH 3– H 2 O ejector-absorption refrigeration cycle, and an R-152a ejector refrigeration cycle are employed with a renewable energy power generator to make a proposed compact power generation and triple effect ejector-absorption refrigeration cycle. The exergy analysis of the cycle leads to a possible performance improvement. Approximately 71.69% of the input exergy is destructed due to irreversibilities in different components. Around 7.976% is available as the useful exergy output. The exhaust exergy lost to the environment is 20.33%, which is lower than the exhaust energy loss of 47.95%, while the useful energy output is 27.88%. The refrigerants used are of zero ODP and negligible GWP, and the CO 2 emission of the exhaust gases is very small as compared to that of the fossil fuel run engine, hence, this cycle is favorable to the global environment. The results also show that the proposed cycle has significant higher energy and exergy efficiency than the earlier investigated 'triple effect refrigeration cycle' and 'the combined power and ejector-refrigeration cycle'.

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