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| 3. |
- Delsing, Jerker, et al.
(författare)
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Projekt: Fjärrvärme
- 2007
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Annan publikation (populärvet., debatt m.m.)
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| 4. |
- Jomni, Yassin, et al.
(författare)
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Architecture for internet enabled measurements in a district heating substation laboratory
- 2005
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Ingår i: Proceeding AMCTM 2005.
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Konferensbidrag (refereegranskat)abstract
- An architecture for the energy measurement and control and monitoring at a district heating substation is propsoed. A district heating substation is comprised of a set of sensors and actuators crutial for the well being of the substation. We want to make the data from the sensors available over the internet and provide access to the control system of the district heating substation over the internet. This technology will be implemented in a district heating laboratory being constructed at Lulea ̊ University of Technology.The architecture is based on wireless sensor and actuator nodes each talking the TCP/IP Internet suite of protocols. The implementation is made with the wireless Embedded Internet System plattform MULLE that supports the TCP/IP suite of protocols. The basic architecture and means for its implementation is given. Other applications where this vision can be readily applied are for example, sports and metrology.
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| 6. |
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| 7. |
- Jomni, Yassin, et al.
(författare)
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Improving heat energy measurement using a feed-forward method for low power applications
- 2004
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Konferensbidrag (refereegranskat)abstract
- Heat measurement errors cause large revenue discrepancies in the district heating industry. Some of these errors are static and can be estimated using standard error analysis, but the largest error cause is the dynamic load such systems are subject to, as in the case of warm water tapping. The frequency at which heat meters estimate and update the energy is either constant or depends on the flow rate. They are often battery operated and their power consumption is proportional to their estimation frequency. Heat meters with a flow rate dependent estimation frequency are usually based on volume-flow meters. They are widely used in district heating due to their lower estimation frequency, which prolongs their battery life. Such devices are inaccurate especially at low flow rates. A Feed-forward method that measures the heat energy only when changes occur is presented in this paper.This method reduces the heat measurement error due to the dynamics of the system while minimizing the battery power consumption. The Feed-Forward method has been implemented and tested at cross-purposes with flow rate dependent heat meters in a Simulink model of a district heating substation.
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| 8. |
- Jomni, Yassin
(författare)
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Improving heat measurement accuracy in district heating substations
- 2004
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The idea of district heating is to heat up a whole district from a central source through a distribution network. The heat is extracted from the distribution network by heat exchangers and the water is then subsequently returned to the central. The heat exchange between the district heating network and the building occurs in district heating substations. Heat meters are located in such substations and are divided into two main categories depending on their heat energy estimation frequency modes which is either constant or flow rate dependent. The Swedish district heating industry is a business with a revenue of appreciatively 19.8 billions SEK (as of the year 2002). Considering an error of 1% in energy delivered, that is a loss of 198 million SEK, which justifies the current research. The accuracy in heat measurement for billing purposes is then one of the major reasons for conducting this research. There are few works done in this area. A Swedish study shows that the major causes to the errors are: flow meters, temperature sensors, integrating units, lightnings, control systems, valves, leaks in heat exchangers and the dynamic heat demand imposed on the district heating substation. I have chosen to study the heat measurement errors due to dynamic load imposed on the district heating substation because it is the least investigated and stands for a substantial portion of the total error. A major tool in the investigation have been simulations based on a Simulink model of a district heating substation and a house. For the purpose the simulation model has been extended to handle new heat measurement strategies. Based on analysis of the measurement strategies an adaptive algorithm and a feed-forward method are proposed in this thesis to reduce the heat measurement errors due to the dynamic heat demand imposed on the substation. Simulations conducted show that the adaptive algorithm has a higher measurement accuracy than both kinds of existing heat meters. The feed-forward method has the highest measurement accuracy compared to both kinds of existing heat meters and the adaptive algorithm.
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| 9. |
- Jomni, Yassin
(författare)
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Improving heat measurement accuracy in district heating substations
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The idea of district heating is to heat up a whole district from a central source through a distribution network. The heat is extracted by heat exchangers and the water is then subsequently returned to the central source. The heat exchange between the district heating network and the building occurs in district heating substations. Heat meters are located in such substations and are divided into two main categories depending on their heat energy estimation frequency modes. Which are either constant or flow rate dependent. The Swedish district heating industry is a business with revenue of approximately 19.8 billion SEK (as of the year 2002). Considering an error of 1% in energy delivered, that is a loss of 198 million SEK, which justifies the current research. The accuracy in heat measurement for billing purposes is then one of the major reasons for conducting this research. Few studies have been done in this area. A Swedish study shows that the major causes of the errors are: flow meters, temperature sensors, integrating units, lightning, control systems, valves, leaks in heat exchangers and the dynamic heat demand imposed on the district heating substation. I have chosen to study the heat measurement errors due to dynamic load imposed on the district heating substation because they are the least investigated and presumably account for a substantial portion of the total error. I have delimited my research area to include single family houses, since the effects of dynamic heat load on heat metering are more important in this kind of dwelling. A major tool in the investigation has been simulations based on a Simulink model, of a district heating substation and a house. For this purpose, the simulation model has been extended to handle new heat measurement strategies. A district heating laboratory was built at Luleå University of Technology to test not only the accuracy of different heat measurement algorithms but also control and diagnosis methods. Based on analysis of the measurement strategies, an adaptive algorithm and a feed-forward method are proposed in this thesis to reduce the heat measurement errors due to the dynamic heat demand imposed on the substation. Simulations conducted show that the adaptive algorithm has a higher measurement accuracy than both kinds of existing heat meters. The feed-forward method has the highest measurement accuracy compared to both kinds of existing heat meters and the adaptive algorithm.
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