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Modelling heat recovery from urban wastewater systems - case study from Malmö

Reyes, Diego LU (2019) VVAM01 20191
Chemical Engineering (M.Sc.Eng.)
Abstract
The purpose of this thesis is to estimate how much heat can be recovered from the sewer system in Malmö, Sweden, and determine the best location for that heat recovery. In fulfilling that purpose, this thesis covers the process of modeling wastewater flows and temperature changes in the sewer system in Malmö, the results of those processes, and the estimated amount of heat that can be recovered from the sewer system. The methods used to complete this study included primary data collection through in-sewer equipment installation and field data measurements, along with the use of two different models (one for a city-wide wastewater flow rate prediction and the other regarding heat transfer in the sewer network). Extensive secondary research... (More)
The purpose of this thesis is to estimate how much heat can be recovered from the sewer system in Malmö, Sweden, and determine the best location for that heat recovery. In fulfilling that purpose, this thesis covers the process of modeling wastewater flows and temperature changes in the sewer system in Malmö, the results of those processes, and the estimated amount of heat that can be recovered from the sewer system. The methods used to complete this study included primary data collection through in-sewer equipment installation and field data measurements, along with the use of two different models (one for a city-wide wastewater flow rate prediction and the other regarding heat transfer in the sewer network). Extensive secondary research was also conducted. The results from this study included the estimation of different amounts of heat from the sewer system. For example, a scheme of heat extraction of 36,000 kW during a 12-hour period was analyzed during the same time frame where flow and temperature data was collected. That number would always keep a temperature at the wastewater treatment plant over 9 ºC and corresponds to 6.3% of the total district heating consumption per year in Malmö. Also, a 1% difference between the real and modeled wastewater flows for one of the catchments on the city was obtained. Finally, the temperature modeling process delivered differences between 0.1 and 0.3 ºC for one of the studied places. (Less)
Popular Abstract
What if the heat contained in the water released through your sink every morning after showering or brushing your teeth could be transformed in energy for your smartphone? Even more, does reclaiming that heat back to the water so your utility bills would get cheaper sound attractive for you? Well, this project aims to determine how much of that heat can be recovered without affecting the wastewater treatment plant in the city of Malmö using computerized models. Thus, two main steps are followed: modeling the wastewater flow and temperature for the total population of Malmö, and modeling different amounts of heat recovered using field data. The modeling process of the wastewater flows delivered differences as small as 1% between the real... (More)
What if the heat contained in the water released through your sink every morning after showering or brushing your teeth could be transformed in energy for your smartphone? Even more, does reclaiming that heat back to the water so your utility bills would get cheaper sound attractive for you? Well, this project aims to determine how much of that heat can be recovered without affecting the wastewater treatment plant in the city of Malmö using computerized models. Thus, two main steps are followed: modeling the wastewater flow and temperature for the total population of Malmö, and modeling different amounts of heat recovered using field data. The modeling process of the wastewater flows delivered differences as small as 1% between the real and the modeled data. For the temperature model, that difference was between 0.1 and0.3 °C. Finally, the results from simulation heat extractions from the wastewater suggested that 6.3% of the total energy demand of the district heating in Malmö can be reclaimed maintaining a temperature at the wastewater treatment plant over 9 °C.

Modeling on a city like Malmö can facilitate the decision-making process and lower costs of heat-recovery projects overall due to the estimation of amounts of heat that can be reclaimed. Also, by emphasizing the importance of finding ways to be sustainable, this project aims to deliver solutions to create sustainable cities. For example, tap water heating and the supply for house heating consumes up to 90% of the total energy used in the urban water cycle. Thus, by implementing solutions that allow for the reclaim of that huge amount of energy will reduce the overall energy demand of a city like Malmö.

The work done during the project included the installation of temperature sensors for the wastewater in different places in the city and subsequent visits to those places to collect the registered data. The work also involved office labor and several hours of modeling processes. Finally, is important to say that the results from this project make part of the knowledge that is being created around the amazing topic of heat recovery. (Less)
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author
Reyes, Diego LU
supervisor
organization
course
VVAM01 20191
year
type
H2 - Master's Degree (Two Years)
subject
keywords
Heat, Recovery, Wastewater, City, Wide, Model, Urban, Sustainability, Sewer, System, Malmo, Temperature, Sweden, Water engineering, Environmental engineering, Vattenförsörjningsteknik, Avloppsteknik
language
English
id
8985009
date added to LUP
2019-07-04 13:14:39
date last changed
2019-07-04 13:14:39
@misc{8985009,
  abstract     = {The purpose of this thesis is to estimate how much heat can be recovered from the sewer system in Malmö, Sweden, and determine the best location for that heat recovery. In fulfilling that purpose, this thesis covers the process of modeling wastewater flows and temperature changes in the sewer system in Malmö, the results of those processes, and the estimated amount of heat that can be recovered from the sewer system. The methods used to complete this study included primary data collection through in-sewer equipment installation and field data measurements, along with the use of two different models (one for a city-wide wastewater flow rate prediction and the other regarding heat transfer in the sewer network). Extensive secondary research was also conducted. The results from this study included the estimation of different amounts of heat from the sewer system. For example, a scheme of heat extraction of 36,000 kW during a 12-hour period was analyzed during the same time frame where flow and temperature data was collected. That number would always keep a temperature at the wastewater treatment plant over 9 ºC and corresponds to 6.3% of the total district heating consumption per year in Malmö. Also, a 1% difference between the real and modeled wastewater flows for one of the catchments on the city was obtained. Finally, the temperature modeling process delivered differences between 0.1 and 0.3 ºC for one of the studied places.},
  author       = {Reyes, Diego},
  keyword      = {Heat,Recovery,Wastewater,City,Wide,Model,Urban,Sustainability,Sewer,System,Malmo,Temperature,Sweden,Water engineering,Environmental engineering,Vattenförsörjningsteknik,Avloppsteknik},
  language     = {eng},
  note         = {Student Paper},
  title        = {Modelling heat recovery from urban wastewater systems - case study from Malmö},
  year         = {2019},
}