A Thermo-Economic and Emissions Analysis of Different Sanitary-Water Heating Units Embedded Within Fourth-Generation District-Heating Systems

Poredoš, Primož; Vidrih, Boris; Kitanovski, Andrej; Poredoš, Alojz

doi:10.1115/1.4040102

Cited by 3 publications

(3 citation statements)

References 17 publications

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“…. Q i x shw (10) and scenarios with boosters, Figure 1b-d, by employing the equation: (11) where K represents the ratio between the booster heating power and the DHS input heating power:…”

Section: Exergy-analysis Modelmentioning

confidence: 99%

“…The SPF values were determined by performing simulations using the test reference year (TRY) for Ljubljana [19]. For more information regarding the determination of the SPF, please refer to an article by Poredoš et al [10]. Table 2 shows the relation between the SPF of a water-water heat pump and the return temperatures at the consumer base (secondary side).…”

Section: Exergy-analysis Modelmentioning

confidence: 99%

“…These boosters raise the temperature of the heat from a district heating system to the standard range of 50-55 • C required for SHW. The technologies applied are dependent on various factors, with the most common booster types being electric-boiler, gas-boiler, and heat-pump boosters [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

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Exergy Analyses of Low-Temperature District Heating Systems With Different Sanitary Hot-Water Boosters

Poredoš

Kitanovski

Poredoš³

2019

Entropy

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This paper presents an exergy-efficiency analysis of low-temperature district heating systems (DHSs) with different sanitary hot-water (SHW) boosters. The required temperature of the sanitary hot water (SHW) was set to 50 °C. The main objective of this study was to compare the exergy efficiencies of a DHS without a booster to DHSs with three different types of boosters, i.e., electric-, gas-boiler- and heat-pump-based, during the winter and summer seasons. To achieve this, we developed a generalized model for the calculation of the exergy efficiency of a DHS with or without the booster. The results show that during the winter season, for a very low relative share of SHW production, the DHS without the booster exhibits favorable exergy efficiencies compared to the DHSs with boosters. By increasing this share, an intersection point above 45 °C for the supply temperatures, at which the higher exergy efficiency of a DHS with a booster prevails, can be identified. In the summer season the results show that a DHS without a booster at a supply temperature above 70 °C achieves lower exergy efficiencies compared to DHSs with boosters at supply temperatures above 40 °C. The results also show that ultra-low supply and return temperatures should be avoided for the DHSs with boosters, due to higher rates of entropy generation.

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“…. Q i x shw (10) and scenarios with boosters, Figure 1b-d, by employing the equation: (11) where K represents the ratio between the booster heating power and the DHS input heating power:…”

Section: Exergy-analysis Modelmentioning

confidence: 99%

Section: Exergy-analysis Modelmentioning

confidence: 99%

See 1 more Smart Citation

Exergy Analyses of Low-Temperature District Heating Systems With Different Sanitary Hot-Water Boosters

Poredoš

Kitanovski

Poredoš³

2019

Entropy

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Thermodynamic, Economic, and Environmental Comparison Between the Direct and Indirect CO2 Refrigeration Cycle With Conventional Indirect NH3 Cycle With Considering a Heat Recovery System in an Ice Rink: A Case Study

Momeni

Keshtkar

2019

Journal of Energy Resources Technology

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In industrial refrigeration systems, such as ice rinks, because of consumption of a lot of energy, the selection of a refrigeration system is very important. At this work, environmental considerations are combined with thermodynamics and economics for the comparison of three different refrigeration systems in an ice rink, including the NH3/brine, CO2/brine, and full CO2. The first law of thermodynamics is used to calculate the system's coefficient of performance (COP) and the second law of thermodynamics is applied to quantify the exergy destructions in each component of a refrigeration system. With regard to the above, the exergy efficiency and energy consumption of the systems are determined by taking into account the heat recovery process that has been performed in the above-mentioned cycles. The results indicate that if a heat recovery system has been used in the refrigeration system, coefficient of performance of full CO2 refrigeration system is 33% higher than the CO2/brine and 66% greater than the NH3/brine system. The results also show that, whatever the refrigeration evaporating temperature in the NH3/brine system reaches lower than −12.4 °C, the total cost of this system will be greater than the full CO2 system.

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Analysis of the Influence of Transient State of the Overhead Pipeline Placed in an Open-Air Space on the Accuracy of its Insulation Assessment Based on the Results of Outer Shell Thermovision Diagnostics

Kruczek

2019

Journal of Energy Resources Technology

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The proper thermal diagnostics of pipeline insulation is an important problem. The heat losses from the pipelines depend distinctly on the quality of this insulation. Changes in weather conditions cause transient accumulation of energy in the pipeline insulation and may cause difficulties during evaluation of the quality of the pipeline thermal insulation. Generally, the goal of this investigation was to identify the scale of energy accumulation inside thermal insulation. This is important because during the calculation of heat losses from thermal pipelines on the basis of infrared camera temperature measurement results usually a steady thermal state inside the insulation is assumed. In order to determine the distributions of the temperature inside the insulation, the calculations of the temperature changes inside the pipeline insulation for real changeable meteorological conditions with the use of software ansys-fluent and others have been carried out. Both the heat transfer between the inner pipeline tube and outer pipeline shell and energy accumulation inside the pipeline elements were considered. For the pipeline insulation evaluation purpose, different coefficients for the analysis of energy accumulation scale were defined and used. The measurement results of the temperature of inner pipeline tube and outer pipeline shell gathered during the operation of the special experimental rig were used as input data for the aforementioned numerical simulations. In these calculations, they constituted the first (Dirichlet's) boundary condition. The conclusions resulting from this work are useful for specialists involved in the technical evaluation of the thermal protection features of pipelines.

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A Thermo-Economic and Emissions Analysis of Different Sanitary-Water Heating Units Embedded Within Fourth-Generation District-Heating Systems

Cited by 3 publications

References 17 publications

Exergy Analyses of Low-Temperature District Heating Systems With Different Sanitary Hot-Water Boosters

Exergy Analyses of Low-Temperature District Heating Systems With Different Sanitary Hot-Water Boosters

Thermodynamic, Economic, and Environmental Comparison Between the Direct and Indirect CO2 Refrigeration Cycle With Conventional Indirect NH3 Cycle With Considering a Heat Recovery System in an Ice Rink: A Case Study

Analysis of the Influence of Transient State of the Overhead Pipeline Placed in an Open-Air Space on the Accuracy of its Insulation Assessment Based on the Results of Outer Shell Thermovision Diagnostics

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