Experience from a practical test of low-temperature district heating for space heating in five Danish single-family houses from the 1930s

Østergaard, Dorte Skaarup; Svendsen, Svend

doi:10.1016/j.energy.2018.06.142

Cited by 37 publications

(26 citation statements)

References 22 publications

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“…Wellfunctioning TVs guarantee the indoor air temperature fluctuating within a certain range around the set values, no matter what operation strategy was applied. On the contrary, the indoor air temperature and the system return temperature would be with fault when the TVs have malfunctions [37,38]. As shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Operation strategies to achieve low supply and return temperature in district heating system

Nord

2019

E3S Web Conf.

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Low temperature is the most significant feature of the future district heating (DH) - the 4th generation district heating (4GDH). The revolutionary temperature level (50–55/25°C) will improve the efficiency of heat sources, thermal storages, and distribution systems, meanwhile, bring huge potentials to renewable energies. One challenge of transition to the future DH is the compatibility of current customer installations and the future temperature level. The aim of this study was to find the temperature potential of Norwegian residential buildings for the future DH system. A reference apartment was created, and typical space heating (SH) system was designed. A detailed building and SH system model were built in Modelica® language, and simulation was conducted via Dymola environment. Different operation strategies: PI control of the supply temperature, weather compensated control of the supply temperature, and PI control of the return temperature were tested. The results of the study showed the average supply temperature could be as low as 56~58°C, and only limited time the temperature was above 60 °C, when the controlled supply temperature strategies were applied. For the case with controlled return temperature strategies, the average return temperature were 30 and 37°C, while the average required supply temperature could be 72 and 94°C. The conclusion was that the low supply temperature could be achieved through optimized operation strategies. Whereas, the low return temperature was not able to be achieved only by improving the operation strategy.

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Section: Resultsmentioning

confidence: 99%

Operation strategies to achieve low supply and return temperature in district heating system

Nord

2019

E3S Web Conf.

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“…Table summarises the various types of DH networks based on the technical requirements of the buildings and in accordance with the previous definitions. The overall conclusion of some recent studies is that there is a large potential for using low‐temperature DH for space heating in existing buildings …”

Section: Configuration Of a District Heating Systemmentioning

confidence: 99%

“…The overall conclusion of some recent studies is that there is a large potential for using low-temperature DH for space heating in existing buildings. 52,53 DH networks must be designed, built, and operated so as to ensure the continuity of the heat supply at all specified operating conditions. Moreover, given the high investment needed, heat losses, and pumping energy consumption, along with maintenance and operation costs, the solutions must be optimal both technically and economically.…”

Section: Heat Distribution Networkmentioning

confidence: 99%

A review of modelling and optimisation techniques for district heating systems

2019

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Summary This article provides an extensive survey on the modelling and optimisation of district heating systems (DHSs) focused on the heat distribution network. For this purpose, the major components of a DHS have been described and discussed, and their modelling has been briefly reviewed, including numerical simulation models for heat sources, end‐users, and especially the distribution network. The main deterministic and heuristic optimisation techniques are briefly described. Additionally, a single‐objective and multiobjective optimisation problem is generally formulated, and the main optimisation criteria for the design and operation of the distribution network are synthesised and analysed. The state of the art in DHS optimisation has been also reviewed and categorised. Finally, some recommendations for future developments were included.

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“…However, in many countries, there is a lack of specific regulations and targets to support this important transition, which involves the decrease of temperatures in existing networks. In some cases, DH systems would be compatible with low-temperature operation [10], but there is no interest for DH operators to reach lower temperatures and integrate RES with generally high investment costs.…”

Section: Policy Indicationsmentioning

confidence: 99%

“…An additional threat to the economic sustainability of future DH systems is an excessive insulation of buildings, which can lead to excessive payback times for the required infrastructure [9]. In some practical experiences, the importance of a proper monitoring and control of the actual operating parameters in the users' heating systems has been found to be a crucial aspect for the optimization of the DH network [10]. The use of simulation models can be an important support in evaluating the benefits that can be reached in existing systems [11], and different approaches have been used in modeling DH systems, including simplified RC models [12] and more complex models based on machine learning techniques [13].…”

Section: Introductionmentioning

confidence: 99%

Analysis of Different Strategies for Lowering the Operation Temperature in Existing District Heating Networks

et al. 2019

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District heating systems have an important role in increasing the efficiency of the heating and cooling sector, especially when coupled to combined heat and power plants. However, in the transition towards decarbonization, current systems show some challenges for the integration of Renewable Energy Sources and Waste Heat. In particular, a crucial aspect is represented by the operating temperatures of the network. This paper analyzes two different approaches for the decrease of operation temperatures of existing networks, which are often supplying old buildings with a low degree of insulation. A simulation model was applied to some case studies to evaluate how a low-temperature operation of an existing district heating system performs compared to the standard operation, by considering two different approaches: (1) a different control strategy involving nighttime operation to avoid the morning peak demand; and (2) the partial insulation of the buildings to decrease operation temperatures without the need of modifying the heating system of the users. Different temperatures were considered to evaluate a threshold based on the characteristics of the buildings supplied by the network. The results highlight an interesting potential for optimization of existing systems by tuning the control strategies and performing some energy efficiency operation. The network temperature can be decreased with a continuous operation of the system, or with energy efficiency intervention in buildings, and distributed heat pumps used as integration could provide significant advantages. Each solution has its own limitations and critical parameters, which are discussed in detail.

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Experience from a practical test of low-temperature district heating for space heating in five Danish single-family houses from the 1930s

Cited by 37 publications

References 22 publications

Operation strategies to achieve low supply and return temperature in district heating system

Operation strategies to achieve low supply and return temperature in district heating system

A review of modelling and optimisation techniques for district heating systems

Analysis of Different Strategies for Lowering the Operation Temperature in Existing District Heating Networks

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