System effects of lowered district heating supply temperatures

2020 ◽  
pp. 14-24
Author(s):  
Tina Lidberg ◽  
Thomas Olofsson ◽  
Louise Ödlund
Keyword(s):  
Power Plants ◽  
Energy Use ◽  
Cost Optimization ◽  
District Heating ◽  
Energy System ◽  
Primary Energy ◽  
Combined Heat And Power ◽  
Electricity Production ◽  
Fuel Use ◽  
Significant Difference

Lowering temperature levels of a district heating (DH) system may offer several advantages such as reduced distribution losses, increased efficiency of flue gas condensation equipment and increased electricity generation in combined heat and power plants. In a broader perspective this can result in more efficient use of natural resources as well as reduced climate-impacting emissions. This study examines how decreased DH supply temperatures influence the power-to-heat ratio and thereby electricity production and fuel use in a combined heat and power plant. Carbon dioxide equivalent (CO2-eqv.) emissions and primary energy use were calculated with three different marginal electricity perspectives. A regional DH system situated in mid-Sweden was used as a case study and the energy system cost optimization modelling tool MODEST (Model for Optimization of Dynamic Energy Systems with Time-Dependent Components and Boundary Conditions) was used. The results show that decreasing the DH supply temperature results in increased electricity production as well as increased fuel use within the system. Further, there is a significant difference in CO2-eqv. emissions and primary energy use for the studied marginal electricity perspectives.

District Heating Cost Optimization

2016 ◽  
Author(s):  
Aaron P. Eicoff
Keyword(s):  
Energy Use ◽  
Cost Optimization ◽  
Capacity Utilization ◽  
District Heating ◽  
Cost Effective ◽  
System Optimization ◽  
Energy System ◽  
Hot Water ◽  
Central System ◽  
District Energy

When buildings of various use-types are served by a district energy system, many societal benefits occur, including improved capacity utilization, reduced energy use, and more cost-effective redundancy. In addition, a central system may benefit financially from commodity leveraging, utility incentives and cogeneration. Energy conversion and transport efficiency for steam and hot water are explored and presented. System optimization curves, including generation and distribution, are presented along with long-term financial comparisons to decentralized systems.

scholarly journals A Comparison of Different Approaches for Assessing Energy Outputs of Combined Heat and Power Geothermal Plants

2021 ◽  
Vol 13 (8) ◽  
pp. 4527
Author(s):  
Daniele Fiaschi ◽  
Giampaolo Manfrida ◽  
Barbara Mendecka ◽  
Lorenzo Tosti ◽  
Maria Laura Parisi
Keyword(s):  
Power Generation ◽  
Low Temperature ◽  
Power Plants ◽  
District Heating ◽  
Primary Energy ◽  
Combined Heat And Power ◽  
Geothermal Systems ◽  
Allocation Scheme ◽  
Component Level ◽  
Temperature Level

In this paper, we assess using two alternative allocation schemes, namely exergy and primary energy saving (PES) to compare products generated in different combined heat and power (CHP) geothermal systems. In particular, the adequacy and feasibility of the schemes recommended for allocation are demonstrated by their application to three relevant and significantly different case studies of geothermal CHPs, i.e., (1) Chiusdino in Italy, (2) Altheim in Austria, and (3) Hellisheidi in Iceland. The results showed that, given the generally low temperature level of the cogenerated heat (80–100 °C, usually exploited in district heating), the use of exergy allocation largely marginalizes the importance of the heat byproduct, thus, becoming almost equivalent to electricity for the Chiusdino and Hellisheidi power plants. Therefore, the PES scheme is found to be the more appropriate allocation scheme. Additionally, the exergy scheme is mandatory for allocating power plants’ environmental impacts at a component level in CHP systems. The main drawback of the PES scheme is its country dependency due to the different fuels used, but reasonable and representative values can be achieved based on average EU heat and power generation efficiencies.

scholarly journals Techno-economic and environmental performances of heating systems for single-family code-compliant and passive houses

2019 ◽  
Vol 111 ◽  
pp. 03039 ◽  
Author(s):  
Ambrose Dodoo
Keyword(s):  
Power Plant ◽  
Heat Pump ◽  
Power Plants ◽  
Energy Use ◽  
District Heating ◽  
Primary Energy ◽  
Climate Impacts ◽  
Single Family ◽  
Final Energy ◽  
Energy Chain

In this study the implications of different energy efficiency requirements and heating solutions for versions of a single-family house in southern Sweden is explored. Final energy use, primary energy use, climate impacts and lifecycle cost of heat supply are analyzed for the building versions designed to meet the current Swedish BBR 2015 building code and heated with district heating or exhaust air heat pump. A case where the building is designed to the Swedish passive house criteria and heated with exhaust air heat pump is also analyzed. The district heating is assumed to be supplied from combined heat and power plants using bio-based fuels. For the heat pump solutions, cases are analyzed where the electricity supply is from coal-fired condensing power plant or fossil gas combined cycle power plant as baseline scenario, and from a combination of improved fossil power plants and non-fossil power plants as long-term scenario. The analysis considers the entire energy chain from natural resources to the final energy services. The results show that the BBR heat pump heated building use the most primary energy compared to the other two alternatives. Lifecycle cost is reduced by about 7-12% when district heating is used instead of heat pump for a BBR code-compliant building. This study shows the importance of lifecycle and system-wide perspectives in analyzing the resource efficiency and climate impacts as well as economic viabilities of heating solutions for houses.

scholarly journals The differences in energy system demands of competitive male tennis play between fast and slow courts

2019 ◽  
Vol 27 (79) ◽  
pp. 11-14
Author(s):  
Аnna Skorodumova ◽  
Igor Baranov
Keyword(s):  
Lactic Acid ◽  
High Performance ◽  
Energy Use ◽  
Energy System ◽  
Analysis Data ◽  
Significant Difference ◽  
Playing Time ◽  
Acid Pathway ◽  
Motor Density ◽  
Energy Pathways

This study investigated the energy system demand differences between matches played on fast courts and on slow courts of high-performance male players. Matches of Grand Slam matches played by Russian players were analysed. External indicators as such in-point playing time as a proportion of total match time were used to conduct the analysis. Data analysis found significant differences in all measured external indicators such as average match playing time, number of points and in-point time. Results also found a significant difference between match motor density (the percentage of total match time that made up effective playing time) for the two surface types, with the slow surface (clay) match motor density being significantly higher than that of the fast surface (grass and hard court), 14.5% and 12.9%, respectively. Subsequent analysis of point length reveals clay courts that slow courts had a significantly higher percentage of points that lasted more than 10 seconds whilst fast courts has a higher percentage of points under 10 seconds in length. It can be concluded that due to the length of the points, tennis primarily employs the ATP-PCr energy system for energy use, dipping into the anaerobic lactic acid energy pathways more on clay court matches. Whilst the aerobic pathways are not employed heavily in-point, they are still essential, possibly even more on clay court due to greater taxation on the anaerobic lactic acid pathway, as they provide the basis for ATP re-synthesis between points. This signals toward endurance as a major component of fitness in tennis.

scholarly journals Effect of Heat Demand on Integration of Urban Large-Scale Renewable Schemes—Case of Helsinki City (60 °N)

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2164
Author(s):  
Vahid Arabzadeh ◽  
Peter D. Lund
Keyword(s):  
Wind Power ◽  
Large Scale ◽  
Energy Use ◽  
Energy Systems ◽  
Energy System ◽  
Heat Pumps ◽  
Electricity Production ◽  
Population Increase ◽  
Building Energy Efficiency ◽  
Heat Demand

Heat demand dominates the final energy use in northern cities. This study examines how changes in heat demand may affect solutions for zero-emission energy systems, energy system flexibility with variable renewable electricity production, and the use of existing energy systems for deep decarbonization. Helsinki city (60 °N) in the year 2050 is used as a case for the analysis. The future district heating demand is estimated considering activity-driven factors such as population increase, raising the ambient temperature, and building energy efficiency improvements. The effect of the heat demand on energy system transition is investigated through two scenarios. The BIO-GAS scenario employs emission-free gas technologies, bio-boilers and heat pumps. The WIND scenario is based on large-scale wind power with power-to-heat conversion, heat pumps, and bio-boilers. The BIO-GAS scenario combined with a low heat demand profile (−12% from 2018 level) yields 16% lower yearly costs compared to a business-as-usual higher heat demand. In the WIND-scenario, improving the lower heat demand in 2050 could save the annual system 6–13% in terms of cost, depending on the scale of wind power.

scholarly journals Analysis of the Effects of Electrification of the Road Transport Sector on the Possible Penetration of Nuclear Fusion in the Long-Term European Energy Mix

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3634
Author(s):  
Daniele Lerede ◽  
Chiara Bustreo ◽  
Francesco Gracceva ◽  
Yolanda Lechón ◽  
Laura Savoldi
Keyword(s):  
Power Plants ◽  
Nuclear Fusion ◽  
Energy System ◽  
Road Transport ◽  
The Other ◽  
Electricity Production ◽  
Transport Sector ◽  
Consumption Pattern ◽  
Deep Penetration ◽  
The Road

The European Roadmap towards the production of electricity from nuclear fusion foresees the potential availability of nuclear fusion power plants (NFPPs) in the second half of this century. The possible penetration of that technology, typically addressed by using the global energy system EUROFusion TIMES Model (ETM), will depend, among other aspects, on its costs compared to those of the other available technologies for electricity production, and on the future electricity demand. This paper focuses on the ongoing electrification process of the transport sector, with special attention devoted to road transport. A survey on the present and forthcoming technologies, as foreseen by several manufacturers and other models, and an international vehicle database are taken into account to develop the new road transport module, then implemented and harmonized inside ETM. Following three different storylines, the computed results are presented in terms of the evolution of the road transport demand in the next decades, fleet composition and CO 2 emissions. The ETM results are in line with many other studies. On one hand, they highlight, for the European road transport energy consumption pattern, the need for dramatic changes in the transport market, if the most ambitious environmental goals are to be pursued. On the other hand, the results also show that NFPP adoption on a commercial scale could be justified within the current projection of the investment costs, if the deep penetration of electricity in the road transport sector also occurs.

scholarly journals Advanced Control of a District Heating System with High Residential Domestic Hot Water Demand

2020 ◽  
Vol 160 ◽  
pp. 01004 ◽  
Author(s):  
Stanislav Chicherin ◽  
Lyazzat Junussova ◽  
Timur Junussov
Keyword(s):  
Energy Demand ◽  
Energy Use ◽  
District Heating ◽  
Heating System ◽  
Primary Energy ◽  
Hot Water ◽  
District Heating System ◽  
Domestic Hot Water ◽  
Extreme Load ◽  
Flow Controller

Proper adjustment of domestic hot water (DHW) load structure can balance energy demand with the supply. Inefficiency in primary energy use prompted Omsk DH company to be a strong proponent of a flow controller at each substation. Here the return temperature is fixed to the lowest possible value and the supply temperature is solved. Thirty-five design scenarios are defined for each load deviation index with equally distributed outdoor temperature ranging from +8 for the start of a heating season towards extreme load at temperature of -26°C. All the calculation results are listed. If a flow controller is installed, the customers might find it suitable to switch to this type of DHW supply. Considering an option with direct hot water extraction as usual and a flow controller installed, the result indicates that the annual heat consumption will be lower once network temperatures during the fall or spring months are higher. The heat load profiles obtained here may be used as input for a simulation of a DH substation, including a heat pump and a tank for thermal energy storage. This design approach offers a quantitative way of sizing temperature levels in each DH system according to the listed methodology and the designer's preference.

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