| 1. |
- Bengtsson, Cecilia, 1974, et al.
(author)
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Co-ordination of pinch technology and the MIND method : applied to a Swedish board mill
- 2002
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In: Applied Thermal Engineering. - 1359-4311 .- 1873-5606. ; 22:2, s. 133-144
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Journal article (peer-reviewed)abstract
- By combining the pinch technology and the MIND method, it is possible to identify beneficial and energy-efficient measures in a complex industrial energy system. By tackling a problem on the two different aggregation levels, the result is thoroughly evaluated and durable measures are achieved. The strength of the combination of methods is elucidated in a case study where a Scandinavian pulp and paper mill is analysed. The studied problem concerns pre-evaporation of effluents in a board mill using excess heat. Different alternatives are evaluated, taking into account economic, technical and practicable constraints. The results show that it is cost-effective to pre-evaporate the effluent using excess heat in the studied mill.
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| 2. |
- 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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| 3. |
- Feng, Xiao, et al.
(author)
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Critical COP for an economically feasible industrial heat-pump application
- 1997
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In: Applied Thermal Engineering. - : Elsevier BV. - 1359-4311. ; 17:1/January 1997, s. 93-101
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Journal article (peer-reviewed)abstract
- In this paper, the expression for critical COP is derived for an economically feasible industrial heat-pump application. It is a function of the price ratio between input energy and heating, the price ratio between equipment and energy, and the payback period. Using this critical COP, a preliminary assessment can be made of whether an industrial heat-pump application is worth discussing further. The influences of various economic factors on the critical COP for different types of heat pumps are also discussed.
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| 4. |
- Harvey, Simon, 1965, et al.
(author)
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Predicting black liquor gasification combined cycle powerhouse performance accounting for off-design gas turbine operation
- 2004
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In: Applied Thermal Engineering. - 1359-4311. ; 24:1, s. 111-126
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Journal article (peer-reviewed)abstract
- Estimating potential electric power generation in the pulping industry by implementing black liquor gasification combined cycle (BLGCC) technology is an important issue, given the anticipated future demand for "green" electricity. Full-scale BLGCC technology has not yet been commercially demonstrated. Therefore, performance studies of this technology require the use of computer simulation tools, with the pertaining challenge of simulating gas turbine operation on gasified black liquor fuel. Exact future plant size is usually unknown; therefore many studies adopt a simplified model assuming an engine sized to match the available fuel stream, with generic characteristics representative of a given class of engine. The performance of a fixed size engine operating at off-design conditions on low calorific value fuel is in most cases lower. This work attempts to quantify the resulting difference between performance estimates based on these two assumptions. The calculations are performed for a BLGCC powerhouse integrated with the Swedish KAM reference pulp mill, for which the biofuel (bark and black liquor) available on-site is more than sufficient to satisfy the mill steam demand. The surplus can therefore be used for additional power generation, which however implies the use of low efficiency condensing steam turbine units. Alternatively, surplus biofuel can be exported for use elsewhere. This study investigates both of these options.
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| 5. |
- Wang, Lieke, et al.
(author)
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Optimal design of plate heat exchangers with and without pressure drop specifications
- 2003
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In: Applied Thermal Engineering. - 1359-4311. ; 23:3, s. 295-311
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Journal article (peer-reviewed)abstract
- The traditional design method for plate heat exchangers(PHEs), either epsilon-number of transfer units (epsilon-NTU) or logarithmic mean temperature difference method, involves many trials in order to meet the pressure drop constraints. This can be avoided through the developed design method, which takes the full utilization of the allowable pressure drops as a design objective. The proposed method is valid for the design situations with and without pressure drop specifications. In the case of the design with pressure drop specification, only one stream can fully utilize the allowable pressure drop. In the case of no pressure drop specification, allowable pressure drops can be determined through economical optimization. Compared to the previous design method, the proposed method does not require many trial iterations. Instead, all heat exchanger parameters, including plate size, number of passes, path, fluid velocity, etc., are determined in a straightforward way. Moreover, the suggested method can guarantee that the optimized values of allowable pressure drops can be fully utilized simultaneously by the two streams. In addition, the optimal corrugation angle is discussed for the most common chevron-type PHEs. (C) 2002 Elsevier Science Ltd. All rights reserved.
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| 6. |
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| 7. |
- Gebremedhin, Alemayehu, 1962-
(author)
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The role of a paper mill in a merged district heating system
- 2003
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In: Applied Thermal Engineering. - 1359-4311 .- 1873-5606. ; 23:6, s. 769-778
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Journal article (peer-reviewed)abstract
- Recent studies have shown that there is great potential benefit in utilities collaborating around heat supply. Analyses based on an extended system boundary clarify the advantage of mutual co-operation in the district heating markets. The purpose of this study is to show how far a local paper mill affects the degree of co-operation between two utilities. Current and future electricity prices and existing and potential plants are considered in the different scenarios in the study. The results in all the scenarios clearly show that the paper mill plays an active role in an integrated heat supply system. The scenario where co-operation, new plants and future electricity prices are considered, gives the lowest total system cost. A new back pressure turbine with a higher electricity-to-heat output ratio in combination with high trade prices promotes increased electricity and heat generation in the co-generation plant. The proportion of combined heat and power in district heating would increase if co-operation between the players were encouraged. ⌐ 2003 Elsevier Science Ltd. All rights reserved.
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| 8. |
- Gustafsson, Stig-Inge
(author)
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Economic benefits from load management in a carpentry factory
- 1996
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In: Applied Thermal Engineering. - : Elsevier. - 1359-4311 .- 1873-5606. ; 16:10, s. 829-834
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Journal article (peer-reviewed)abstract
- As a result of a National Referendum and a subsequent parliament decision Sweden will phase out its nuclear power stations before the year 2010. This source of electricity accounts for about half the total electricity usage and therefore other sources must be constructed, or the country must use less electricity. One way to accomplish this, according to economic theory, is to increase the price of electricity, and we will probably be subject to such actions, at least if there is a risk of a shortage of electricity. Hitherto, most interest for saving energy has been emphasised on space and domestic hot water heating in buildings. The major part of electricity, however, is used in industry, and is therefore worth studying in more detail. One small carpentry plant which manufactures wooden staircases and fibreboard panels for ceilings has been studied. Using monitored data for 1 year of their electricity usage and costs, the amount of money which could be saved by the owner of the factory, if different load management measures had been applied, has been calculated. Thus it was possible to find the maximum cost for equipment that can turn off some processes, such as timber dryers, for short periods.
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| 9. |
- Gustafsson, Stig-Inge
(author)
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Municipal thermal and electricity loads : A case study in Linköping
- 1998
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In: Applied Thermal Engineering. - : Elsevier. - 1359-4311 .- 1873-5606. ; 18:5, s. 257-263
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Journal article (peer-reviewed)abstract
- Linear programming models used for optimisation of various energy systems have received increased interest during the last ten years. One reason for this is the use of personal computers. Models with thousands of variables and constraints can now be rapidly optimised. If integers are introduced, which are necessary when increments or steps in cost functions are part of the model, the computing power is of even higher interest. However, many scientific authors do not discuss in detail how the model is designed and what basic data lie behind this design. This paper presents an attempt to study municipal thermal and electricity loads, and further how to divide data for one year into useful segments for linear and mixed integer programming purposes
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| 10. |
- Gustafsson, Stig-Inge
(author)
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Optimization and simulation of building energy systems
- 2000
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In: Applied Thermal Engineering. - 1359-4311 .- 1873-5606. ; 20:18, s. 1731-1741
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Journal article (peer-reviewed)abstract
- The Mixed Integer Linear Programming (MILP) technique is a useful tool for the optimization of energy systems. However, the introduction of integers in linear models results in a severe drawback because the ranging process is no longer available. Therefore, it is not possible to study what happens to the solution if input data are changed. In this paper, we compare a MILP model of a building with a simulation model of an identical case. Both models describe a building with a number of possible retrofits. Using the MILP technique, the optimal retrofit strategy is calculated, after which certain input data are changed. The optimization results in the lowest possible Life-Cycle Cost (LCC) of the building, and the paper describes how much the LCC will change if the property owner chooses other solutions. An increase in a particular data value may cause the LCC to increase or decrease. It may also be unchanged. Only a few data reduce the LCC when their values are increased.
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