Defining “Waste Heat” for industrial processes

Bendig, Matthias; Maréchal, François; Favrat, Daniel

doi:10.1016/j.applthermaleng.2013.03.020

Cited by 71 publications

(54 citation statements)

References 19 publications

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“…Thekdi and Belt (2011) look into various excess heat-recovery options and rank them in the order in which they should be considered for improving energy efficiency. The same general hierarchy is discussed in Bendig et al (2013) and in Law et al (2013) based on economic factors. The following order of recovery options should be considered (Thekdi and Belt, 2011):…”

Section: Excess Heat Use Opportunitiesmentioning

confidence: 96%

“…The concept is sometimes used to refer to the share of excess heat that can be used externally, after the share that is technically or economically usable internally has been deducted (Berntsson and Åsblad, 2015). Bendig et al (2013) distinguish between avoidable and unavoidable heat flows, where avoidable heat flows refer to excess heat from a process that is not optimized and unavoidable heat flows to excess heat from a process that is optimized. By making this distinction, it is claimed that one can avoid making investments that ultimately overlook more energy-efficient measures.…”

Section: Excess Heat: Origin and Definitionsmentioning

confidence: 99%

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System studies of the use of industrial excess heat

Viklund¹

2015

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Energy, materials, and by-products, can be exchanged between companies, having positive effects in the form of improved resource efficiency, environmental benefits, and economic gains. One such energy stream that can be exchanged is excess heat, that is, heat generated as a by-product during, for example, industrial production. Excess heat will continue to play an important role in efforts to reduce greenhouse gas (GHG) emissions and improve energy efficiency. Using excess heat is therefore currently emphasized in EU policy as a way to reach EU climate targets.This thesis examines the opportunities of manufacturing industries to use industrial excess heat, and how doing so can positively affect industry, society, and the climate. Since different parts of the energy system are entangled, there is an inherent complexity in studying these systems and introducing excess heat in one part of the energy system may influence other parts of the system. This analysis has accordingly been conducted by combining studies from various perspectives, by applying both quantitative and qualitative methods and covering a broad range of aspects, such as technical possibilities as well as climate, policy, economics, and resource aspects.The results identify several opportunities and benefits accruing from excess heat use. Although excess heat is currently partly used as a thermal resource in district heating in Sweden, this thesis demonstrates that significant untapped excess heat is still available. The mapping conducted in the appended studies identifies excess heat in different energy carriers, mainly low-temperature water. Analysis of excess heat use in different recovery options demonstrated greater output when using excess heat in district heating than electricity production. Optimizing the trade-offs in excess heat used in a district heating network, heatdriven cooling, and electricity production under different energy market conditions while minimizing the system cost, however, indicated that the attractiveness of excess heat in district heating depends on the type of heat production in the system. Viewing excess heat as a low-cost energy source also makes it economically interesting, and creates opportunities to invest in excess heat-recovery solutions. Excess heat is often viewed as CO 2 neutral since unused excess heat may be regarded as wasted energy. The GHG mitigation potential of using excess heat, however, was found to be ambiguous. The appended studies demonstrate that using excess heat for electricity production or for applications that reduce the use of electricity reduces GHG emissions. The effects of using excess heat in district heating, on the vi other hand, depend on the energy market development, for example, the marginal electricity production and marginal use of biomass, and on the type of district heating system replaced. The interviews performed reveal that energy policy does influence excess heat use, being demonstrated both to promote and discourage excess heat use. Beyond national energy polic...

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Section: Excess Heat Use Opportunitiesmentioning

confidence: 96%

Section: Excess Heat: Origin and Definitionsmentioning

confidence: 99%

System studies of the use of industrial excess heat

Viklund¹

2015

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“…Emphasizing the quality of the waste heat, this approach is based on the Carnot factor [3]. Note that the electrical power used by the chiller compressors has the exergy value equal to the energy.…”

Section: Exergy Analysis Approachmentioning

confidence: 99%

“…As stated by Bendig M [3] not only the quantity, but also the quality of the heat available at different temperature should be taken into account to be used in secondary process. The quality of low grade waste heat is defined by minimum temperature difference which is needed for the heat exchange and transfer of heat into the heat sink [4].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the Heat Recovery Potential by Using an Exergy Analysis Approach to Improve Energy Efficiency of Industrial Refrigeration Systems

Taheri¹,

Gadow²

2017

IJMMM

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Abstract-This work applies an exergy analysis approach to investigate the performance and waste heat recovery potential of an industrial air-cooled screw chiller. To reduce the factory overall primary energy demand, a 410 kW chiller with 274 kW heat reclaim capability for generation of 70˚C hot water, was analyzed. The evaluation was established based on system irreversibility and Total Recovery Potential (TRP) or exergy efficiency of the recovered heat.For evaluation of the total recovery potential, exergy efficiency of the refrigeration system with heat recovery was expressed in terms of recovery efficiency and effectiveness to identify the importance and contribution of each term to improve the exergy efficiency. The analysis was conducted for various cooling capacity for the analysis boundary including the refrigeration system and the suitable used point e.g. water or space heating.It was concluded that due to the low quality of the waste heat from the refrigeration system, total recovery potential or exergy efficiency of the recovered heat was more a question of effectiveness rather than merely an efficiency-based evaluation. Therefore TRP was low, approximately 6-12%, even though the recovery efficiency reached up to 94% for the half load capacity. Also it was observed that due to the higher compressor power demand for the system with heat recovery, COP and COP Ex were 3.43 and 3 respectively which were quite lower than of the values for conventional refrigeration system. Index Terms-Exergy efficiency, air-cooled chiller, total recovery potential, waste heat recovery.

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“…For example, in Sweden the supply temperature varies between 70° in summer to 120°C in winter (Ericsson, 2009). Bendig et al (2013) presented a method for identifying, characterising and quantifying industrial excess heat that would be viable to recover. They distinguished between avoidable and unavoidable excess heat and stated that the avoidable excess heat should not be used for external applications, because it could prevent investments in energy efficiency measures.…”

Section: Recovery Of Industrial Excess Heatmentioning

confidence: 99%

Improved Energy Efficiency and Fuel Substitution in the Iron and Steel Industry

Johansson¹

2014

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IPCC reported in its climate change report 2013 that the atmospheric concentrations of the greenhouse gases (GHG) carbon dioxide (CO2), methane, and nitrous oxide now have reached the highest levels in the past 800,000 years. CO2 concentration has increased by 40% since pre-industrial times and the primary source is fossil fuel combustion. It is vital to reduce anthropogenic emissions of GHGs in order to combat climate change. Industry accounts for 20% of global anthropogenic CO2 emissions and the iron and steel industry accounts for 30% of industrial emissions. The iron and steel industry is at date highly dependent on fossil fuels and electricity. Energy efficiency measures and substitution of fossil fuels with renewable energy would make an important contribution to the efforts to reduce emissions of GHGs. This thesis studies energy efficiency measures and fuel substitution in the iron and steel industry and focuses on recovery and utilisation of excess energy and substitution of fossil fuels with biomass. Energy systems analysis has been used to investigate how changes in the iron and steel industry’s energy system would affect the steel plant’s economy and global CO2 emissions. The thesis also studies energy management practices in the Swedish iron and steel industry with the focus on how energy managers think about why energy efficiency measures are implemented or why they are not implemented. In-depth interviews with energy managers at eleven Swedish steel plants were conducted to analyse energy management practices. In order to show some of the large untapped heat flows in industry, excess heat recovery potential in the industrial sector in Gävleborg County in Sweden was analysed. Under the assumptions made in this thesis, the recovery output would be more than three times higher if the excess heat is used in a district heating system than if electricity is generated. An economic evaluation was performed for three electricity generation technologies for the conversion of low-temperature industrial excess heat. The results show that electricity generation with organic Rankine cycles and phase change material engines could be profitable, but that thermoelectric generation of electricity from low-temperature industrial excess heat would not be profitable at the present stage of technology development. With regard to fossil fuels substituted with biomass, there are opportunities to substitute fossil coal with charcoal in the blast furnace and to substitute liquefied petroleum gas (LPG) with bio-syngas or bio synthetic natural gas (bio-SNG) as fuel in the steel industry’s reheating furnaces. However, in the energy market scenarios studied, substituting LPG with bio-SNG as fuel in reheating furnaces at the studied scrap-based steel plant would not be profitable without economic policy support. The development of the energy market is shown to play a vital role for the outcome of how different measures would affect global CO2 emissions. Results from the interviews show that Swedish steel companies regard improved...

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Defining “Waste Heat” for industrial processes

Cited by 71 publications

References 19 publications

System studies of the use of industrial excess heat

System studies of the use of industrial excess heat

Evaluation of the Heat Recovery Potential by Using an Exergy Analysis Approach to Improve Energy Efficiency of Industrial Refrigeration Systems

Improved Energy Efficiency and Fuel Substitution in the Iron and Steel Industry

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