Use Of Excess Heat Research Articles

Environmental and economic assessment of industrial excess heat recovery collaborations through 4th generation district heating systems

The external use of excess heat from industrial processes is an important factor in the energy transition and 4th generation district heating is an enabling technology. This paper presents a calculation tool for assessing the economic feasibility and the environmental impact of collaborations between potential industrial sources and users. The tool supports the sizing of district heating pipe diameters, pumps, heat pumps, and heat storage systems. A distinctive feature of the model is the possibility of calculating carbon and blue water footprints, alongside economic indicators, for both existing stand-alone systems and potential collaborative configurations. Excess heat recovery from water-cooled condensers of refrigeration systems is evaluated for two case studies involving the space heating of offices in a food logistics hub and the heating of a greenhouse from a frozen pizza factory, respectively. Only the second collaboration is profitable with the baseline price of natural gas (0.04 €/kWh) and electricity (0.12 €/kWh), provided that the distance between the source and the user is less than 2 km. For higher gas prices, distances of approximately 8 km would be viable. However, for source-user distances above 5 km, the water footprint of the collaboration would be higher than that of stand-alone systems.

Combining techno-economic modeling and spatial analysis for heat planning in rural regions: A case study of the Holbæk municipality in Denmark

This study examines the opportunities and challenges related to heat decarbonization in rural municipalities by applying a spatial analysis in combination with techno-economic modeling using TIMES. While the transition to low-carbon heating technologies is progressing in urban areas, this shift is happening more slowly in rural areas, reflecting a difference in decarbonization rate between urban and rural contexts. This study takes the Holbæk Municipality in Denmark as a case to investigate the potential for rural heating systems considering local fuels, excess heat, and investments in different energy infrastructures. The technology options investigated include both individual heating technologies, such as domestic boilers and heat pumps, and district heating. The modeling results demonstrate that use of excess heat from the municipal wastewater treatment plant and the neighboring industrial site for district heating competes with individual heating systems that have heat pumps and biogas-fueled boilers, where the mix depends on the conditions assumed for each technology and the heat demand density. The extent of district heating expansion differs between districts in the municipality, ranging from 14% to 100% depending on the heat demand density and proximity to the current district heating network. The different possibilities for the transition of the heating sector revealed in this work indicate that a successful transition will require both a clear policy for the heating sector and an explicit decarbonization strategy for the industries that can provide excess heat for district heating.

Experimental and Numerical Analysis of Temperature Reduction Potentials in the Heating Supply of an Unrenovated University Building

Lowering the temperatures in heating systems is the key to decarbonizing the heat supply in the building sector, because it is a door opener to greater integration of renewable heat, the use of excess heat and to improve compatibility for heat pumps. This often fails because heating systems, especially in unrenovated building stock, usually require high supply temperatures. Previous studies on temperature reduction in existing buildings are performed mainly numerically, whereas in this research the numeric calculations are validated by measurements. For this purpose, a demonstrator with two different ceiling heating systems is integrated in the listed architecture building of the Technical University of Darmstadt and the achievable temperature reduction is investigated. Based on this, parameter variations are conducted through a simulation model in order to test the feasibility of the concept for the entire building. The results show that even with an unrenovated building envelope, a significant temperature reduction to below 45 °C is possible without exceeding the normative limits of thermal comfort. With moderate building envelope renovation, the reduction is possible even to below 36 °C. The measures investigated can make the building compatible with renewable heat potentials without negative impacts on the cultural heritage.

Integrating bio-oil production from wood fuels to an existing heat and power plant - evaluation of energy and greenhouse gas performance in a Swedish case study

Combined heat and power (CHP) production in combination with a district heating (DH) grid gives an energy-efficient use of wood fuels. The heat demand in the DH grid will, however, decline in the coming decades, and operators are seeking additional heat sinks. In this case study, the integration of a pyrolysis unit into an existing CHP plant was investigated as a possible solution. The retrofitted pyrolysis unit makes use of excess heat and yields a liquid bio-oil. Pyrolysis integrated with CHP production was shown to give a net energy yield of at least 80%, and to decrease the net heat output to the DH grid. The carbon footprint of the delivered heat was very low at maximum 1.6 g CO2eq/MJ. Prolonging the operation of the pyrolysis unit to periods without heat delivery to the DH grid would increase the use of existing installations, but at the cost of energy yields decreasing to 63–70%. Up to 2.8 PJLHV/yr crude bio-oil could be produced at the investigated CHP plant. The bio-oil was shown to have a low carbon footprint, 1.7–4.0 g CO2eq/MJLHV, which makes it attractive for the rapidly expanding transport biofuel market.

Gärrestaufbereitung als Beitrag zur Nährstoffentfrachtung von Überschussregionen – Kosten und Treibhausgasemissionen

The processing of slurry and biogas digestate reduces their volume and separates nutrient flows, especially in regions with nutrient surpluses. This makes it possible to cut transport costs for supra-regional utilisation and to configure tailor-made products for different customers. However, the additional capital and equipment costs can usually only be compensated by revenue from the CHP bonus for the use of excess heat from combined heat and power systems in biogas plants, unless high prices can be achieved for the products outside agriculture. The use of heat also has a considerable impact on the greenhouse gas emissions associated with processing. If reference emissions are charged because the heat is no longer available to replace fossil resources, this far outweighs savings from transport. However, it is not possible to draw general conclusions due to the diverse plant-specific conditions (amount and type of nutrient surplus, transport distance, heat availability, size of the plant, etc.). In individual cases, the processing of biogas digestate may well be economically viable, especially in the case of long transport distances.

Advanced configurations for post-combustion CO2 capture processes using an aqueous ammonia solution as absorbent

In this work, we have developed advanced process configurations for solvent-based CO2 capture processes that use aqueous ammonia as absorbent. In total, ten different advanced configuration concepts have been optimized and analysed, aiming at: (i) achieving in spec NH3 emissions in a controlled way; (ii) minimizing capital costs by avoiding redundant process components; (iii) minimizing the energy demand of the capture process by minimizing the requirements of high temperature steam and by maximizing the possibilities for the use of excess heat from the CO2 point source. As a result, we propose a new benchmark configuration for NH3-based capture processes that, with proper tuning of the process operating conditions, allows to minimize the specific energy consumption while enhancing the flexibility of the capture process with respect to the type and to the features of the electricity and steam available at the CO2 point source, at the minimum consumption of chemicals and process water. This new benchmark configuration for NH3-based capture processes is built upon the Chilled Ammonia Process, avoids the formation of solids and includes: (i) a multi-pressure desorber with recycled vapour compression that is able to decrease the high temperature steam requirements for solvent regeneration, i.e. at ca. 140–160 °C, to values as low as 1.1 MJthkgCO2captured−1, (ii) a vacuum integrated stripper for the recuperation of the solvent that is able to use low temperature steam instead, i.e. below 100 °C, and (iii) a flue gas water-wash column that is able to reduce the NH3 concentration in the CO2-depleted flue gas to values below 10 ppmv without the need of an acid-wash column before the stack.

Assessing the potential contribution of excess heat from biogas plants towards decarbonising residential heating

Abstract This paper analyses the technical potential for utilising excess heat from biogas plants, in order to supply local settlements through district heating. Based on a survey of around 600 biogas plant operators, the fractions of excess heat from the cogeneration units in these plants are analysed. A heuristic is developed to match biogas plants (heat sources) with local settlements (heat sinks) in order to determine a least-cost district heating supply for residential buildings. Two criteria are employed, namely the CO2 abatement costs and the payback period, which represent the macro- and microeconomic perspectives respectively. Based on the survey, the mean fraction of excess heat is 40%, which is in agreement with other empirical studies. Extrapolating this fraction to the German biogas plant stock, which is selected as a case study, leads to technically feasible CO2 savings of around 2.5 MtCO2/a. Employing the criteria of CO2 abatement costs and payback period yields about 2 MtCO2/a below CO2 abatement costs of 200 €/tCO2 and below a payback period of 9 years. This represents about 0.25% of the total German CO2 emissions in 2016 or around 2.5% of all CO2 in residential buildings. Alternative threshold values of 80 €/tCO2 and 5 years payback period reduce the carbon reduction potential to about 0.5 MtCO2 and 0.75 MtCO2 respectively. These relatively high average costs are related to the typically low population density in rural regions where biogas plants are located. These potentials are concentrated in around 3,500 of 11,400 municipalities, where district heating from biogas plants could reduce CO2 emissions per capita by an average of 250 kgCO 2 / a and cover 12% of the total heating demand. Apart from a methodology that can be transferred to any country with comparable data availability, the present study demonstrates that the use of excess heat in biogas plants can contribute to global decarbonisation.

Technical and economic feasibility of sustainable heating and cooling supply options in southern European municipalities-A case study for Matosinhos, Portugal

Energy demand for heating and cooling constitutes almost 50% of the total energy demand in Europe and strongly depends on fossil fuels. Decarbonising this sector and providing a sustainable supply should be a main goal of climate policy. The technical and economic feasibility of supply options depends strongly on local conditions. The focus of this research is to assess the cost-effectiveness of sustainable heat and cold supply solutions under southern European conditions. We use the city of Matosinhos (Portugal) as an example. The methodology includes estimation of thermal demands and hourly simulation of alternative supply scenarios.The results show that, from a socio-economic perspective, the use of excess heat from a refinery via a DHC network might be the economically most competitive option. In addition, the heat pump system combined with photovoltaics is cost-effective from a socio-economic perspective compared to the status quo if the capital costs of the status quo are also accounted for. This justifies support policies to also make it cost-competitive from a private economic perspective, which it currently is not. Sensitivity analyses were conducted for the most influential factors like capital investment costs, interest rate, and fuel prices.

A feasibility study of improved heat recovery and excess heat export at a Swedish chemical complex site

New ambitious targets for reduced greenhouse gas emissions and increased energy efficiency in industry and in the stationary energy sector provide incentives for industrial plants to investigate opportunities for substantially increasing recovery and use of excess heat from their operations. This work investigates the economic feasibility of recovering industrial excess heat at a Swedish chemical complex site for increased site internal heat recovery or export to a regional district heating (DH) network. The work is based on investment cost data estimated in previous work by the authors. A site-wide heat collection and distribution system based on circulating hot water was envisioned, which is also connected to a regional DH network. With the help of multiobjective optimization, the optimal heat contributions from the individual plant sites were identified that minimize the total system cost for a large range of options involving different quantities of internally recovered heat and heat export to the DH system. A payback period analysis was conducted together with a risk assessment to take into account uncertainty regarding utility steam production cost and heat sale price. The results of the study indicate that a payback period of around 3 years can be achieved for a number of cases in which 30% to 50% of the total excess heat produced by the site plants is recovered. Although it seems more profitable to recover heat at the site rather than exporting heat to the DH system only, profitability appears to be maximized by hybrid solutions that allow a share of the excess heat to be sold to the DH system and some heat to be recovered at the site simultaneously.

Thin issues products of processing waste heaps as raw materials for ceramic wall products

Shown high perspectivity of production of wall ceramics products on the basis of fine-grained gob pile processed products with a high content of coal constituent. The characteristics of these materials, which are actually a ready-made ceramic fusion mixture, as well as the characteristics of the products obtained depending on the roasting temperature, are given. The established relationship between the various properties of the products obtained, the compressive strength of which is from 10 to 19 MPa, at a low density. Recommendations on the main technological parameters of production are given. It is emphasized that low prime cost of products is caused: excluding the costs of raw materials associated with the development and maintenance of fields; practical absence of costs for mass preparation; drying of products due to heat extraction from the furnace; lack of fuel costs necessary for roasting. It is pointed out that in the production of wall ceramics products based on fine-grained waste products of waste heaps, additional sources of income appear that are associated with a reduction in capital and current costs for the maintenance of dumps of FGPPP and the use of excess heat in various directions.

System profitability of excess heat utilisation – A case-based modelling analysis

The use of EH (excess heat) in DH (district heating) may contribute to increased sustainability through reduced use of primary energy. In Sweden, while biomass has become the most important DH fuel during the last decades, there is a significant amount of industrial EH that could be utilised in the DH systems if it could be shown to be an economically viable alternative. This study addresses the long-term system profitability of a large heat network between a cluster of chemical industries and two DH systems that enables an increased use of EH. An assessment is carried out by scenario and sensitivity analyses and by applying the optimising energy systems model MARKAL_WS, in which the DH systems of the Västra Götaland region of Sweden are represented individually. The results show heat network profitability under most assumptions, and that the profitability increases with biomass competition, phase-out of natural gas use and higher CO2 charges, whereas it decreases with the availability of other EH sources in the base load of the DH systems.

Effect of the use of industrial excess heat in district heating on greenhouse gas emissions: A systems perspective

European policy promotes increased use of excess heat as a means to increase the efficiency of resource use. By studying possible effects on greenhouse gases, this article aims to analyze and discuss system aspects of the use of industrial excess heat in district heating. Effects on greenhouse gas emissions are studied by applying different energy market conditions with different system boundaries in time and space. First, life cycle assessment is used to assess the introduction of excess heat in district heating in a contemporary system with different geographical system boundaries. Thereafter, future energy market scenarios for Europe are investigated to explore possible future outcomes. This study concludes that both the heat production system and the energy market conditions affect the system emission effects of using excess heat in district heating. Industrial excess heat in district heating can be beneficial even if it leads to reduced local electricity production when unused biomass can be used to replace fossil fuels. It is recommended that a strengthened EU policy should encourage the use of biomass where it has the most favorable effects from a systems perspective to ensure emission reductions when industrial excess heat is used in district heating.

Industrial excess heat use: Systems analysis and CO2 emissions reduction

The adopted energy efficiency directive stresses the use of excess heat as a way to reach the EU target of primary energy use. Use of industrial excess heat may result in decreased energy demand, C ...

Biogas production supported by excess heat – A systems analysis within the food industry

The aim of this paper was to study the effects on greenhouse gases and economics when a change is made in the use of industrial organic waste from external production and use of biogas (A) to internal production and use (B). The two different system solutions are studied through a systems analysis based on an industrial case. The baseline system (A) and a modified system (B) were compared and analysed. Studies show that industrial processes considered as integrated systems, including the exchange of resources between industries, can result in competitive advantages. This study focuses on the integration of internally produced biogas from food industry waste produced by a food company and the use of excess heat. Two alternative scenarios were studied: (1) the use of available excess heat to heat the biogas digester and (2) the use of a part of the biogas produced to heat the biogas digester. This study showed that the system solution, whereby excess heat rather than biogas is used to heat the biogas digester, was both environmentally and economically advantageous. However, the valuation of biomass affects the magnitude of the emissions reduction. Implementing this synergistic concept will contribute to the reaching of European Union climate targets.

Technologies for utilization of industrial excess heat: Potentials for energy recovery and CO2 emission reduction

Industrial excess heat is a large untapped resource, for which there is potential for external use, which would create benefits for industry and society. Use of excess heat can provide a way to reduce the use of primary energy and to contribute to global CO2 mitigation. The aim of this paper is to present different measures for the recovery and utilization of industrial excess heat and to investigate how the development of the future energy market can affect which heat utilization measure would contribute the most to global CO2 emissions mitigation. Excess heat recovery is put into a context by applying some of the excess heat recovery measures to the untapped excess heat potential in Gävleborg County in Sweden. Two different cases for excess heat recovery are studied: heat delivery to a district heating system and heat-driven electricity generation. To investigate the impact of excess heat recovery on global CO2 emissions, six consistent future energy market scenarios were used. Approximately 0.8TWh/year of industrial excess heat in Gävleborg County is not used today. The results show that with the proposed recovery measures approximately 91GWh/year of district heating, or 25GWh/year of electricity, could be supplied from this heat. Electricity generation would result in reduced global CO2 emissions in all of the analyzed scenarios, while heat delivery to a DH system based on combined heat and power production from biomass would result in increased global CO2 emissions when the CO2 emission charge is low.

Co-production of Pyrolysis Oil in District Heating Plants: Systems Analysis of Dual Fluidized-Bed Pyrolysis with Sequential Vapor Condensation

Flash pyrolysis of biomass yields a liquid applicable as a fuel oil substitute and as a basis for production of chemicals and fuels. Biomass, being a renewable resource, is foreseen to be in increasing demand. An increased usage may lead to scarcity of biomass and emphasizes the need for high-efficiency conversion processes. In this study, the efficiency and capacity aspects of an integration of pyrolysis oil production with a district heating plant by means of dual fluidized-bed technology has been modeled. Further, fractional condensation of the pyrolysis vapors has been applied, enabling part of the condensation energy to be recovered. The concept shows potential for significant pyrolysis oil production while keeping the delivered power and heat constant. The use of excess heat from the pyrolysis production in the district heating net results in a 10% higher overall efficiency than production without heat supply to the district heating net.

Action of climate conditions on heat transfer through the fencing constructions of buildings and use of excess heat for their heating

The problem of heat transfer through the fencing constructions of buildings was numerically solved with account for a set of climate factors. A partial solution of the problem on the use of excess heat produced by the Sun for heating of buildings is proposed.

Heat supply alternatives for CO2 capture in the process industry

An economic analysis for post-combustion CO2 capture in a petrochemical industry has been performed. Previous studies have shown that the largest costs are related to the costs for energy supply. In this study we therefore focus on how heat can by supplied to the capture process in the most cost-efficient way. Five different heat supply options have been evaluated by using an energy market scenario tool together with a variation of the specific heat demand (reboiler duty). Three stand-alone options (natural gas combined cycle, natural gas boiler and biomass boiler) and two excess heat options (use of current excess heat and optimal use of excess heat) were analysed. For the stand-alone alternatives, the fuel consumption and co-generation of electricity are important. The best alternatives were the ones using excess heat. Considering that the process integration potential in the process industry generally is high and expecting high future CO2 charges, these options may become profitable. A quantification of the capture costs per CO2 avoided using excess heat shows costs in the range of 37–70€/t CO2, which are comparable to costs reported for oxy-fuel combustion in petrochemical industries as well as for post-combustion in the power sector.

Wärmenutzungskonzepte für Biogasanlagen

In biogas plants the use of excess heat from cogeneration increases the energy effi ciency substantially and is taking rising prices for energy crops into account. Using model calculations the infl uence of heat utilization on the economic feasibility of biogas plants is investigated. Heat utilization for the processing of digestion residues and the heating of greenhouses are evaluated. While the use of excess heat for heating greenhouses is economic feasible for all cases considered, the drying of digestion residues requires a profi table use as fertilizer. The larger the biogas plant, the greater economic improvement by heat utilization can be achieved.

Making Use of Excess Heat

The single biggest opportunity to increase the "energy productivity" of American industry is to make use of heat that would otherwise be thrown away. One way to do that is via cogeneration, or "combined heat and power," a technique that is more than a century old but newly fashionable.