| 1. |
- Andersson, Jan-Erik, et al.
(author)
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Energy mapping in the sawmill industry with focus on drying kilns
- 2013
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Conference paper (peer-reviewed)abstract
- The forest industry stands for approximately 11 % of Sweden’s total export. However, the forest industry is energy intensive. In 2008, sawmill industry alone consumed almost 8,7 TWh of energy, corresponding to 5 % of the Swedish industries total energy consumption. Out of their total consumption, 2200 GWh was electric power, 194 GWh heating oil , 4229 GWh bio-fuel, 574 GWh district heating, and other fuels such as diesel 1503 GWh [1].The project ”EESI- Energy Efficiency in the Sawmill Industry” was started in the spring of 2010 with the aim of demonstrating the possibilities to reduce the energy consumption in the sawmill industry with 20 % by 2020. 16 sawmill corporations and 14 equipment suppliers has joined the project which is carried out in two phases of which the first phase was carried out during 2010 and 2011. EESI has now reached half time and the first energy-saving implementations have been completed at the participating sawmills.This paper presents the energy-mapping, measurements and modelling performed by the participating sawmills during the first phase of the project [2, 3]. The average energy consumption per sawn cubic metre of boards varied between approximately 300 to 500 kWh/m3. Out of this, the electricity consumption was on average 85 kWh/m3, bio-fuel 290 kWh/m3 and diesel 1.8 l/m3.However, the main concern from sawmills regarding energy consumption was the wood drying process. The striking results from the preliminary measurements were the large variation in energy consumption even with similar drying kilns. This was especially apparent for the heat consumption in kiln dryers which could vary as much as 50 % for the same dimension of spruce planks.The results from the first phase of the project resulted in a large number of actions in order to reduce the energy consumption which are now being implemented or have already been completed. Examples of those actions are: simplified management system adapted to sawmills, weighing of packages for more accurate wood drying, reduced speed or intermittent operation of the air circulating fans in batch kilns and moisture content measurements of bio-fuel.References[1] Statistiska centralbyrån (SCB), 2013, Industrins årliga energianvändning 2011, Slutliga uppgifter, EN23SM1301, ISSN 1654-367X. (In Swedish). [2] Andersson, J-E., Lycken, A., Nordman, R., Olsson, M., Räftegård, O., and Wamming, T. State of the art – Energianvändning i den svenska sågverksindustrin. SP Rapport 2011:42, ISBN 978-91-86622-72-5. (In Swedish).[3] Andersson, J-E., Räftegård, O., Lycken, A., Olsson, M., Wamming, T., and Nordman, R. Sammanställning av energimätningar från EESI fas 1. SP Rapport 2011:41, ISBN 978-91-86622-71-8. (In Swedish).
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| 5. |
- Bengtsson, Cecilia, 1974, et al.
(author)
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Utilization of excess heat in the pulp and paper industry - a case study of technical and economic opportunities
- 2002
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In: Applied Thermal Engineering. - 1359-4311. ; 22:9, s. 1069-1081
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Journal article (peer-reviewed)abstract
- Newly developed methods and tools based on pinch technology are used in a case study to investigate the potential and economy of using excess heat for pre-evaporation of chemo thermo mechanical pulp effluent and heat pumping in an integrated pulp and paper mill. The new tools give information about the system that traditional pinch tools such as the grand composite curve or the composite curves would not reveal. For example, the highest temperature levels possible where excess heat can be released are identified together with the amount of excess heat at each temperature level. The new curves are also able to provide information about where heaters and coolers are placed in an existing system. The matrix method has been used successfully in order to find an economically feasible heat exchanger network retrofit for the release of the excess heat found with the curves.The results of the case study show that a pre-evaporation plant can be integrated with the overall process with just a few modifications in the existing process. There are also opportunities for heat pumping in the system. Both projects have a pay-back period shorter than required for implementation.
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| 9. |
- Björk, Kaj-Mikael, et al.
(author)
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Solving large-scale retrofit heat exchanger network synthesis problems with mathematical optimization methods
- 2005
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In: Chemical Engineering and Processing: Process Intensification. - : Elsevier BV. - 0255-2701. ; 44:8, s. 869-876
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Journal article (peer-reviewed)abstract
- Heat exchanger network optimization is a standard problem in process design. Various mathematical models and heuristics have beendeveloped to help the designer in constructing the network. Different target procedures, like the pinch analysis, are widely used both inacademia and industry. Another approach to find cost optimal network structures is to use mathematical programming methods. The advantagewith mathematical programming methods is that a rigorous optimization of the structure, sizes of heat exchangers and utility usage can becarried out, whereas the designer makes these decisions if purely pinch-based tools are used.Even if much effort has been put on research within this area, many of the mathematical models consider only grassroot design, whereasmost practical cases today seem to be retrofit situations. In addition, these models are likely to be either rigorous but not solvable for bigger(large-scale, real life examples) or deficient and solvable for large-scale problems. This paper takes an attempt to address these problemssimultaneously and to develop a rigorous optimization framework based on both a genetic algorithm and a deterministic MINLP-approachand to present an extended model for large-scale retrofit heat exchanger network design problems.
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| 10. |
- Boss, Annika, et al.
(author)
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Uppvärmning och kylning av lokaler ur energi- och miljömässigt samt ekonomiskt perspektiv
- 2009
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Reports (peer-reviewed)abstract
- Demand for cooling of commercial buildings is increasing and there is a potential for expanding district cooling systems, especially in district heating areas. Using district heating and district cooling has been compared to heat pump techniques. Primary energy, environmental influence and economy have been evaluated. Four buildings in Gothenburg have been included in the study and certain differences have been found depending on demands of heating and cooling, which vary according to design and activity. The results are specific for Gothenburg due to the combination of production methods for district heating and cooling and the pricing, which differ compared to other places. Different perspectives on production of electricity, district heating and district cooling, e.g. average or marginal production, is of vital importance when comparing environmental influence. In most of the case studies the demand of primary energy is lower for district heating and cooling compared to heat pump systems. With a marginal perspective district heating and cooling will lead to lower emissions of greenhouse gases. Using the perspective of average production will on the other hand rate heat pump systems to have a lower influence on the greenhouse effect in most of the cases. Which technique is the most cost efficient depends mainly upon relation of heating and cooling demands. Where there is a greater demand for cooling than for heating, district heating and cooling is more advantageous. It is a need for improved data in commercial buildings from reliable field measurements. The quality of the evaluation is very much dependent on reliable measured data from real installations.
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| 16. |
- Kovacs, Peter, et al.
(author)
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Comparison of five approaches to solar assisted cooling
- 2009
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In: 29th Biennial Solar World Congress of the International Solar Energy Society, ISES 2009; Johannesburg; South Africa; 11 October 2009 through 14 October 2009. - 9781617388521 ; 1, s. 423-430
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Conference paper (peer-reviewed)abstract
- Numerous different options are available for cooling buildings using solar energy. In this theoretical study, which is also a pre study for a pilot installation, five generic technologies are compared: 1. Conventional compressor chiller fed by electricity from PV panels 2. Absorption chiller fed by a combination of medium temperature solar heat and district heating 3. Absorption chiller fed by a combination of low to medium temperature solar heat and district heating 4. Evaporative cooling (tower) fed by electricity from PV panels 5. Desiccant cooling fed by medium temperature solar heat and district heating The financial viability of each technology will essentially depend on competing supply energy tariffs, local climate, time distribution of cooling loads, the internal cooling distribution system, subsidy levels and expected operational costs. Furthermore, the buyers' choice of a system will also be affected by the fact that the technologies are in different stages of maturity. From the point of view of the district heating provider potential impact on the heating network is also of great interest. The study compares the five technologies in the light of these different aspects. The paper describes the method in more detail as well as the results of the study. The best overall conditions were found for a combination of PV powered conventional chillers which, according to calculations have a significantly lower LCC than the reference district cooling, even if subsidies are not taken into account. The concept based on free cooling from a wet cooling tower powered by PV has a much lower cost than the chiller, but the technical feasibility of this new and very energy efficient technology is not yet considered to be proven. Results from the economical analysis of solar assisted district heating powered comfort cooling varies within a wide range depending on the tariff applied for the district heat.
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| 18. |
- Nordman, Roger
(author)
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A Common Method for Testing and Rating of Residential HP and AC Annual/Seasonal Performance: Final report : Annex 39
- 2016
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Reports (other academic/artistic)abstract
- In this Annex, the following was aimed to be developed:1) Common calculation methods for SPF using a generalised and transparent approach, based on repeatability and reliable test data from laboratory measurements.2) Establish comprehensive test methods based on further development of existing teststandards. The test standards should include test conditions needed for the future SPF calculations.3) A method to evaluate additional heat pump performance, e.g. Carbon Footprint, Primary Energy Saving or Energy Savings.A matrix of existing standards, test methods and monitoring protocols was assembled, and similarities and differences between these were studied. A swot analysis was performed and proposals for how a harmonisation of test points for lab testing could happen were developed. By this harmonisation, manufacturers could test the performance of heat pumps in any accredited lab and then apply for all certificates that require tested performance, globally.In order to better understand the accuracy of calculation methods to predict real performance, a comparison of existing calculation methods and results from field measurements were made. All calculation methods have underestimated the SPF compared to the monitored value.This Annex has also contributed to the development of a whole new standard in the US the IHP (or multifunction HP) test standard, ANSI/ASHRAE 206-2013.Different methods to calculate and compare heat pumps with other heating technologies were also suggested in this work, mainly based on an LCA perspective, nut also models that calculates the CO2 emissions reduction, or the Primary Energy (PE) use have been proposed.The Japanese team in the Annex has proposed that test chambers should be built and instrumented in the same manner in order to minimise uncertainties between test sites.
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| 21. |
- Nordman, Roger, 1971, et al.
(author)
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Advanced pinch technology based composite curves for evaluating the usable excess heat potential
- 2005
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In: In proceedings of: The 18th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems. Trondheim, Norway June 22-22, 2005. - 8251920418
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Conference paper (peer-reviewed)abstract
- This paper describes the application of a set of advanced composite curves to evaluate the potential to release usable excess heat (hereafter referred to as Qxs) from an existing process industry. Throughout this paper Qxs is defined as heat at enough high temperature to be interesting for use e.g. for district heating. Studies using the advancedcurves reveal information about the existing HEN that traditional graphical methods are not able of, and that for almost the same collected information from the process. This allows for estimations on the heat recovery potential and existing pinch violations before detailed calculations.These curves have earlier been presented in connection with integration of CHP, HP and retrofitting HENs. The curves have also been used to evaluate the Qxs potential in one doctoral thesis, but the methodology was not explained in detail, but rather used as a tool among many. In this paper we broaden the discussion on how to use the curves, whichtraps there might be and how to interpret and use the results. Important questions that are answered are for example: How does the Qxs potential change when the pinch temperature changes? At which temperature is it possible to release Qxs? How could the Qxs be made available? How can the Qxs potential be revealed?
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| 26. |
- Nordman, Roger, 1971, et al.
(author)
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Design of kraft pulp mill hot and warm water systems - A new method that maximizes excess heat
- 2005
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In: Applied Thermal Engineering. - : Elsevier BV. - 1359-4311. ; 26:4, s. 363-373
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Journal article (peer-reviewed)abstract
- Many pulp mill hot and warm water systems are overdimensioned and produce more hot and warm water than demanded. This overproduction could be used for other applications, if heat could be released at high enough temperatures. In this paper a new method to release as much excess heat of a high temperature as possible in the secondary heat system has been developed.A case study of a Swedish kraft pulp mill showed that 5-6 MW excess heat with a temperature above 90oC could be released if the system were rebuilt. Two different alternatives for using the excess heat have been investigated.
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| 33. |
- Nordman, Roger, 1971, et al.
(author)
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New Pinch Technology Based HEN Analysis Methodologies for Cost-Effective Retrofitting
- 2001
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In: Canadian Journal of Chemical Engineering. - : Wiley. - 1404-7098 .- 0008-4034 .- 1939-019X. ; 79:4, August 2001, s. 655-662
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Journal article (peer-reviewed)abstract
- In this paper, new pinch technology based curves for retrofitting of heat exchangers are presented. Advantages compared to traditional pinch curves, and the information that can be extracted from these curves, are discussed. The curves have been applied to an example where different energy saving levels has been studied. The results have been verified by detailed calculations using the Matrix method.
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| 34. |
- Nordman, Roger, 1971
(author)
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New process integration methods for heat-saving retrofit projects in industrial systems
- 2005
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Doctoral thesis (other academic/artistic)abstract
- New graphical methods for HEN retrofit (further development of existing tools), release of usable excess heat and placement of supply tanks in HWWS systems have been developed. In addition, further development of the matrix method for HEN retrofit has been made. The methods have been used in case studies, both as stand-alone tools, and in different combinations.Using the advanced composite curves in combination with the matrix method in HEN retrofit give new insights on which units should be picked for retrofit, and how far the heat recovery should proceed. The extra information that has to be collected to show the placement of existing heaters and coolers give valuable inputs to this method. Calculations showed that heaters and coolers placed close to the pinch are often cheaper by a factor of two and more to retrofit.A method to show the potential to release usable excess heat at high temperature levels (but still below the pinch) has been developed. This method is based on the full set of stream data from the process, and therefore shows the total potential. Case studies have shown that much of the potential is also possible to release by making changes in the HEN with acceptable investments and PBPs.Another method, to be used in HWWS systems for different setups of tanks and different values of DTmin has also been developed. This method shows the potential usable excess heat versus temperature in this sub-system for a user-defined number of supply tanks and DTmin.By studying this sub-system, a large amount of the total potential can be exploited. This leaves the remaining process without any changes at all.A new optimisation routine has been developed and implemented into the matrix method. This method uses a recursive branch and bound algorithm to explore all relevant paths in the retrofit task. A first solution is made and taken as an upper bound to the problem. All following paths that exceed this bound is directly eliminated. The implementation has proven to be reliable and fast to use, although there are still improvements to be made.
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| 46. |
- Nordman, Roger
(author)
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Undersökning av värmepumpars miljöpåverkan
- 2006
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Reports (peer-reviewed)abstract
- This report reviews the environmental effects of heat pumps for single family houses in Sweden. The heat pumps are grouped in the major groups; ground source heat pumps, air-to-water heat pumps, air-to-air heat pumps and exhaust air heat pumps. Environmental effects from material use, manufacturing, operation and scrapping have been studied via a literature survey and discussions with people in the heat pump business. Clearly, the largest effect on the greenhouse effect is from the operation of all the heat pump types. This effect also differs a lot depending on which type of electricity mix that is assumed for the operation. For ground source heat pumps with energy well, the installation causes acidification through the use of diesel oil when the well is drilled. The consumer should carefully examine the efficiency and the capacity when buying a heat pump. These factors are affecting both the energy cost as well as the environment through the greenhouse effect. Buying a high efficiency heat pump with a high capacity therefore is a win-win situation for the consumer and the environment. Keywords: heat pumps, environmental effect, efficiency
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| 47. |
- Nordman, Roger, 1971, et al.
(author)
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Use of advanced composite curves for assessing cost-effective HEN retrofit II. Case studies
- 2009
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In: Applied Thermal Engineering. - : Elsevier BV. - 1359-4311. ; 29:2-3, s. 282-289
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Journal article (peer-reviewed)abstract
- This paper presents the theory and concepts of a graphical method for heat exchanger network (HEN) retrofit that gives new insights about the complexity and possible solutions of different retrofit alternatives. The method uses knowledge about the placement of heaters/coolers in the existing HEN to evaluate the potential for cost-effective retrofit. One general result this method predicts is that the closer to the pinch the existing heaters/coolers are located, the higher the potential for cost-effective retrofit. Networks that are badly engineered from a grass-root perspective, prove to be a good basis for cost-effective retrofits.
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| 49. |
- Olsson, Marcus, et al.
(author)
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Energiintegrerat etanolkombinat baserat på lignocellulosa : Jämförelse mellan svagsyrahydrolys och enzymhydrolys
- 2011
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Reports (peer-reviewed)abstract
- Plants for bioethanol production have been planned in several cities in Sweden, including Borås. This report provides answers to general questions regarding how such a facility's energy demand is affected by the external integration with a heat and power plant and the internal energy integration between process units. Heat integration of a bioethanol plant means that energy is reused as much as is technically possible; this sets a practical minimum level for the energy demand of the plant. In the study, ethanol production from cellulose has been simulated using Aspen Plus. Weak acid hydrolysis and enzymatic hydrolysis have been simulated, each with 50,000 and 100,000 tonnes of ethanol per year, resulting in four simulation cases. In all cases, heat integration is evaluated using pinch analysis. The steam in the ethanol plant has been covered by steam from a heat and power plant similar to that found today in Borås. The reported energy quotas in this report includes energy use for upgrading the residual products. This leads to lower energy quotas than would be the case if the upgrading of residuals were allocated outside of the ethanol production. The conclusions from the project are: - The steam demand of the ethanol plant leads to a reduction in both the electricity and heat production of the heat and power plant. For the weak acid hydrolysis, the electricity loss is relatively high, 26–98%, which will affect the revenue significantly. The loss of electricity production is lower for the enzymatic process: 11–47%. - The difference in decreased electricity between the theoretical case of heating the raw material and the two alternative heating cases is about a factor of two, so the design of the heating of raw material is extremely important. - The reduced heat output of the power plant can, in most cases, be balanced by the surplus heat from the ethanol plant, but to completely balance the shortage, heat over 100°C must be used. - For a future polygeneration plant it is important to consider local conditions, such as the external integration capabilities and the raw materials available. - The choice of process greatly affects the need for raw materials since the yields differ. The lower yield of the weak acid process means that 60% more material is needed compared with the enzymatic process. - To ensure that the process also works in a real plant, research and validation of experiments are needed in full scale facilities. - Energy ratios for the reported cases show that ethanol production from cellulosic raw material ranges from 1.27 to 3.24 for the weak acid process, depending on the choice of process integration alternative, and between 3.51 to 9.56 for the enzymatic process.
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