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| 2. |
- Fröling, Morgan, 1966-, et al.
(författare)
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DISTRICT HEATING AS PART OF THE ENERGY SYSTEM : AN ENVIRONMENTAL PERSPECTIVE ON ‘PASSIVE HOUSES’ AND HEAT REPLACING ELECTRICITY USE
- 2010
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Ingår i: Proceedings of 12th International Symposium onDistrict Heating and Cooling, September 5th –September 7th, 2010, Tallin University of Technology, Tallinn, ESTONIA. - 9789949230150 ; , s. 202-205
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Energy use for space heating, hot tap water and otherheat use at comparatively low temperature levelsrepresent a substantial part of the total energy use inSweden and countries with similar climate. It is thus ofimportance to meet this demand in a way generating assmall environmental impact as possible. However, it ispossible to create a system with higher environmentalimpacts with energy efficient buildings compared toless energy efficient buildings through choice of lessgood energy carriers. It is not enough that theindividual parts of a system are good and efficient togive a low environmental impact; the parts must beconnected into the system in a good way.From environmental perspective energy efficientbuildings and district heating don‘t oppose each other– good parts connected in a good system will give anoptimal. The results from the study of the three items ofhousehold equipment show possibilities for districtheating to be an alternative with good environmentalperformance, but not under all heat generationregimes.
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| 3. |
- Gadd, Henrik, 1967-, et al.
(författare)
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Daily Heat Load Variation in Swedish District Heating Systems
- 2010
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Ingår i: 12th International Symposium on District Heating and Cooling. - Tallinn : Tallinn University of Technology. - 9789949230150 ; , s. 199-201
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Konferensbidrag (refereegranskat)abstract
- If daily heat load variations could be eliminated in district heating-systems, it would make the operation of the district heating system less costly and more competitive . There would be several advantages in the operation such as:Less use of expensive peak load power where often expensive fuels are used.Less need for peak load power capacity.Easier to optimize the operation that leads to higher conversion efficiencies.Less need for maintenance because of more smooth operation of the plantsThere are a number of ways to handle the daily variations of the heat load. Two often used are large heat storages or using the district heating network as temporary storage. If it would be possible to centrally control the customer substations, it would also be possible to use heavy buildings connected to the district heating system as heat storages.To be able to find the best way to reduce or even eliminate the daily heat load variations, you need to understand the characteristics of the daily variations. This paper will describe a way of characterizing daily heat load variations in some Swedish district heating-systems.
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| 4. |
- Gustafsson, Jonas, et al.
(författare)
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Integration of an IP based low-power sensor network in district heating substations
- 2010
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Ingår i: Proceedings of the 12th International Symposium on District Heating and Cooling. - Tallinn. - 9789949230150
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Konferensbidrag (refereegranskat)abstract
- In this study, the implementation of a wireless, lowpower, sensor network with IP capabilities in a district heating substation was evaluated. The aim of the study was to show that an open standard solution is technically feasible. Low-power wireless communication was established using IPv6/6LoWPAN on an IEEE 802.15.4 wireless network. An experimental district heating substation was equipped with sensor platforms in vital devices located within or near a district heating substation. As a result, all connected devices could obtain a direct internet connection.A system with open standards facilitates the introduction of new energy services such as individual measurements and improved space heating control. In this study, we found that resource-limited batterypowered devices possess a life expectancy of over 10 years, using small batteries while participating in IPv6 compatible communication.
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| 5. |
- Magnusson, Dick, 1983-, et al.
(författare)
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Modelling District Heating Cooperations in Stockholm : An Interdisciplinary Study of a Regional Energy System
- 2010
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Ingår i: 12th International Symposium on District Heatingand Cooling. - 9789949230150 ; , s. 288-296
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Konferensbidrag (refereegranskat)abstract
- In this paper, a combination of methods from social science (interviews) and technical science (modelling) have been used to analyse the potential for cooperation in the present and future district heating system in Stockholm. The aim of the paper is to explore barriers and driving forces for energy cooperation in the Stockholm district heating system and to analyse the potential for combined heat and power generation in the system. In the study it was found that with better connectivity in existing systems, the annual system cost would decrease by approximately 10 million €, and with new CHP plants a similar potential exists. There is also a large potential for decreasing the local and global emissions of CO2 with CHP plants. The results from the interviews showed that the existing cooperation has a long history and is working well today. The advantages are higher supply security and economic benefits, while disadvantages are a need for more administration and control because of a more complex system. That the barriers to cooperation are seldom technical is another conclusion. With the combination of methods, we have gained a better understanding of the actual potential for the development of the system.
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| 6. |
- Persson, Urban, 1961-, et al.
(författare)
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Effective Width : The Relative Demand for District Heating Pipe Lengths in City Areas
- 2010
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Ingår i: 12th International Symposium on District Heating and Cooling. - Tallinn : Tallinn University of Technology. - 9789949230150 ; , s. 128-131
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Konferensbidrag (refereegranskat)abstract
- One key concept when assessing network investment cost levels for district heating systems is the linear heat density. In contrast to a traditional way of expressing this quantity entirely on the basis of empirical data, a recently developed analytical approach has made it possible to estimate linear heat densities on the basis of demographic data categories. A vital complementing quantity in this analytical approach is the concept of effective width.Effective width describes the relationship between a given land area and the length of the district heating pipe network within this area. When modelling distribution capital cost levels by use of land area values for plot ratio calculations, there is a potential bias of overestimating distribution capital cost levels in low dense park city areas (e < 0.3). Since these areas often include land area sections without any housing, avoiding overestimations of network investment costs demand some kind of corrective mechanism.By use of calculated effective width values, a compensating effect at low plot ratio levels is achieved, and, hence, renders lower anticipated distribution capital cost levels in low dense park city areas.
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| 7. |
- Reidhav, Charlotte, 1977, et al.
(författare)
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Transient thermal conductivity of flexible district heating twin pipes
- 2010
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Ingår i: 12th International Symposium on District Heating and Cooling; Tallinn; 5-7 September 2010. - 9789949230150 ; , s. 90-95
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The standardized methods to measure the thermal conductivity of straight district heating pipes are not applicable on flexible district heating pipes. This paper presents a transient method determining the temperature dependent thermal conductivity of flexible twin pipes. A transient method to determine the temperaturedependent thermal conductivity of flexible single district heating pipes is presented in this paper. A flexible pipe coil is immersed into cold water. Hot water is distributed in the coil. The temperature decline of the coil water is measured and calculated. Minimizing the difference between the calculated and measured temperatures gives λ(T) of the flexible polyurethane foam. The method gives small errors.
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