scholarly journals COMPARISON REFURBISHMENT MODELS OF DISTRICT HEATING NETWORKS

2013 ◽  
Vol 20 (1) ◽  
pp. 11-20 ◽  
Author(s):  
Algirdas Kuprys ◽  
Ramūnas Gatautis

The renovation of multi-storey residential buildings reduces heat consumption intensity and decreases heat demand, which may have a harmful effect on a district heating supply system. The paper analyses the heat loss change in four district heating distribution networks (DHNs) of Kaunas at the various scenarios of buildings and DHN renovation stages. A bundle of genetic algorithm software package was used to carry out the districts’ distribution network hydraulic calculations in the case of building renovation without changing the hydrodynamic and network routes. The experimental data were used to calculate heat loss for old and new pipes. The computer data of networks used to summarise the cost of DHN then for the renovation of buildings as well as for renovation progress will go evenly with DHN refurbishment. Network optimization results were summarised by functional dependence. The comparison of the projects’ efficiency was analysed in the following cases: the diameters of pipes of DHN were not changed, new diameters of pipes were integrated partly after partial residential buildings renovation and after a complete renovation of residential building and optimisation of pipeline diameters. The efficiency of separate guidelines of the DHN refurbishment project was summarised by performing sensitivity analysis.

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2874 ◽  
Author(s):  
Dmytro Romanchenko ◽  
Emil Nyholm ◽  
Mikael Odenberger ◽  
Filip Johnsson

Using an integrated demand-supply optimization model, this work investigates the potential for flexible space heating demand, i.e., demand response (DR), in buildings, as well as its effects on the heating demand and the operation of a district heating (DH) system. The work applies a building stock description, including both residential and non-residential buildings, and employs a representation of the current DH system of the city of Gothenburg, Sweden as a case study. The results indicate that space heating DR in buildings can have a significant impact on the cost-optimal heat supply of the city by smoothing variations in the system heat demand. DR implemented via indoor temperature deviations of as little as +1 °C can smoothen the short-term (daily) fluctuations in the system heating demand by up to 18% over a period of 1 year. The smoothening of the demand reduces the cost of heat generation, in that the heat supply and number of full-load hours of base-load heat generation units increase, while the number of starts for the peaking units decreases by more than 80%. DR through temperature deviations of +3 °C confers diminishing returns in terms of its effects on the heat demand, as compared to the DR via +1 °C.


Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3706 ◽  
Author(s):  
Ciapała ◽  
Jurasz ◽  
Kies

Geothermal heat is considered a sustainable energy source with significant global potential. Together with heat distribution networks, it can provide clean thermal energy to individual and commercial consumers. However, peaks in heat demand can require additional peaking sources at times. In this paper, we investigated how wind turbines can act as a peak energy source for a geothermal district heating system. We studied a model consisting of a geothermal heat source, a heat storage and wind power generator using historical weather data of Warsaw (Poland) and showed that wind power could increase the renewable share to supply a considerable heat demand compared to a geothermal heat source alone. The results indicate that wind power can be a suitable complement for a geothermal heat source to provide energy for heating. It is shown that a theoretical geo-wind-thermal storage based district heating network supplying 1000 m2, which requires 100 W/m2 at an outdoor temperature of −20 °C should have the following parameters: 4.8 MWh of thermal energy storage capacity, 45 kW of geothermal capacity and 5 kW of wind capacity. Such a system would ensure minimal wind curtailment, high utilization of geothermal source and high reliability of supply.


2014 ◽  
Vol 899 ◽  
pp. 16-23
Author(s):  
Tamás Csoknyai

The residential buildings built with prefabricated technology (also called panel buildings) represent a significant part of the building stock, particularly in Eastern Europe. These buildings are typically 30-40 years old and due to their poor energy performance they have been in the focus of energy policy makers over the recent years. These buildings are typically connected to district heating systems and the continuously decreasing heat demand caused by the renovation subsidy programs resulting in risks of inefficient operation and on the long term it questions the viability of the district heating systems. Therefore it is particularly important to have a clear picture on the energy consumption trends about this segment of the building stock. In this paper, the building stock of the city of Debrecen connected to district heating is analysed. The current energy consumption figures of the buildings are analysed. In Debrecen, the share of retrofitted buildings is relatively low (appr. 15%), therefore a future trend analysis was also carried out. The results of this study can be interesting for other cities as well, particularly those with a significant share of “panel buildings”.


2016 ◽  
Vol 56 (2) ◽  
pp. 81 ◽  
Author(s):  
Mária Čarnogurská ◽  
Romana Dobáková ◽  
Miroslav Příhoda

Existing procedures for determining the heat loss in heat distribution use balance relations, or rather they are based on the theory of heat and mass transfer. Dimensional analysis enables a new point of view that demonstrated the functionality of heat loss from selected physical quantities that contribute to heat loss. The solution provides one complex criterion and four simplex criteria of similarity. Transforming these criteria of similarity leads to the formulation of the functional dependence of only two criteria, on the basis of which the amount of heat loss can be determined. The resulting criterial dependency is simple, and is calculated in this paper for a pipe one meter in longth. The mathematic model for demonstrating the heat loss is of universal validity, and applies to a wide range of piping used for hot water distribution. However, for each nominal diameter of piping it is necessary to take into account the mutual dependency of the dimensionless arguments <em>p</em><sub>5</sub> on <em>p</em><sub>1</sub>, the form of which is always different. In the paper, this dependency is demonstrated for two nominal diameters DN65 and DN125.


Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5724 ◽  
Author(s):  
Irati Uriarte ◽  
Aitor Erkoreka ◽  
Pablo Eguia ◽  
Enrique Granada ◽  
Koldo Martin-Escudero

The existing performance gap between the design and the real energy consumption of a building could have three main origins: the occupants’ behaviour, the performance of the energy systems and the performance of the building envelope. Through the estimation of the in-use Heat Loss Coefficient (HLC), it is possible to characterise the building’s envelope energy performance under occupied conditions. In this research, the estimation of the HLC of two individual residential buildings located in Gainsborough and Loughborough (UK) was carried out using an average method. This average method was developed and successfully tested in previous research for an occupied four-story office building with very different characteristics to individual residential buildings. Furthermore, one of the analysed residential buildings is a new, well-insulated building, while the other represents the old, poorly insulated semidetached residential building typology. Thus, the monitored data provided were filtered in order to apply the abovementioned average method. Even without fulfilling all the average method requirements for these two residential buildings, the method provides reliable HLC values for both residential buildings. For the house in Gainsborough, the best estimated HLC value was 60.2 W/K, while the best approach for Loughborough was 366.6 W/K. Thus, despite the uncertainty sources found during the analysis, the method seems promising for its application to residential buildings.


Author(s):  
Ojeh, N. Vincent ◽  
Oruonye, D. Emeka ◽  
Arisabor, Lucky ◽  
Jutum, Felix ◽  
Dovo John ◽  
...  

The study assessed the two days episodic rainstorm event that destroyed buildings and led to loss of life in April and May 2018 in Taraba State, northeast Nigeria. Data were from primary and secondary sources. A total of 60 copies of research questionnaires and interviews were used, complimented by data from the meteorological observatory of the Department of Geography, Taraba State University and expert eye witness accounts. The results of the study show that the 2-day rainstorm extreme event with high wind speed of over 600 knots (327 m/s) caused devastating damages to building infrastructures in the state and the roofs of buildings and damage to Globacom Telecommunication mast was profound and five people lost their lives with several others sustaining diverse injuries in 17 communities in Jalingo and Wukari. It led to about 62% of the affected to take refuge outside their homes for over three days while other spent more than 10 days. The schools were more affected with an estimated cost of ₦30,000,000 to fix the damaged infrastructures, followed by government buildings which needs about 24,000, 000 and residential building with estimated cost of ₦ 6,275,000. The cost for fixing the infrastructures damaged in Wukari in comparison to Jalingo was ₦ 9,000,000 for residential buildings, ₦ 6,000,000 for government buildings and ₦ 9,275,000 for schools respectively. Prices of roofing sheets increased with about $6 during the period. It was suggested that wind breakers should be encouraged and the cutting down of trees should be discouraged while creating awareness and encouraging afforestation.


2020 ◽  
Vol 17 (1) ◽  
pp. 41
Author(s):  
UMMU SHOLEHAH MOHD NOR

High residential living in Malaysia has not been widely given a significant emphasises in literature despite its increasing scale and significance in the real estate market. The significance of high rise is mainly due the increasing rate of migration from rural to urban. It is estimated a total of 77.2 percent of the Malaysian population lived in urban areas in 2020. Approximately, 30 percent of this urban population lives in strata housing. These percentages are predicted to continue to increase in the future. The emergence of high residential building has been argued as confronting various problems which has considerable impact on this life style. Satisfaction is an important outcome of living in one’s dwelling, although it is not the only consideration. High residential building in Malaysia encountered numerous problems in term of management aspects, legislation aspects, and residents’ satisfaction. The purpose of this paper is to investigate the tenants’ satisfaction living in high residential buildings in Klang Valley. The questionnaires survey is conducted amongst 276 tenants at low cost and medium cost HRB using random sampling in HRB located at areas under jurisdiction Dewan Bandaraya Kuala Lumpur (DBKL), Majlis Bandaraya Subang Jaya (MBSJ), Majlis Bandaraya Shah Alam (MBSA), Majlis Bandaraya Subang Jaya (MBSJ), Majlis Perbandaran Selayang (MPS) and Majlis Perbandaran Ampang Jaya (MPAJ). The result from this study shows that tenant in medium cost residential building are more satisfied in term of facilities and management as compared to tenants in low cost residential building. Tenants also not disclosed to the existing act and procedure related to high residential building. In conclusion, this study suggested the Local Authority to emphasise the role of tenant. These recommendation hopefully will increase the level of satisfaction amongst the residents in HRB.


2021 ◽  
Vol 13 (10) ◽  
pp. 5752
Author(s):  
Reza Sabzehgar ◽  
Diba Zia Amirhosseini ◽  
Saeed D. Manshadi ◽  
Poria Fajri

This work aims to minimize the cost of installing renewable energy resources (photovoltaic systems) as well as energy storage systems (batteries), in addition to the cost of operation over a period of 20 years, which will include the cost of operating the power grid and the charging and discharging of the batteries. To this end, we propose a long-term planning optimization and expansion framework for a smart distribution network. A second order cone programming (SOCP) algorithm is utilized in this work to model the power flow equations. The minimization is computed in accordance to the years (y), seasons (s), days of the week (d), time of the day (t), and different scenarios based on the usage of energy and its production (c). An IEEE 33-bus balanced distribution test bench is utilized to evaluate the performance, effectiveness, and reliability of the proposed optimization and forecasting model. The numerical studies are conducted on two of the highest performing batteries in the current market, i.e., Lithium-ion (Li-ion) and redox flow batteries (RFBs). In addition, the pros and cons of distributed Li-ion batteries are compared with centralized RFBs. The results are presented to showcase the economic profits of utilizing these battery technologies.


Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2405
Author(s):  
Samar Fatima ◽  
Verner Püvi ◽  
Ammar Arshad ◽  
Mahdi Pourakbari-Kasmaei ◽  
Matti Lehtonen

Power distribution networks are transitioning from passive towards active networks considering the incorporation of distributed generation. Traditional energy networks require possible system upgrades due to the exponential growth of non-conventional energy resources. Thus, the cost concerns of the electric utilities regarding financial models of renewable energy sources (RES) call for the cost and benefit analysis of the networks prone to unprecedented RES integration. This paper provides an evaluation of photovoltaic (PV) hosting capacity (HC) subject to economical constraint by a probabilistic analysis based on Monte Carlo (MC) simulations to consider the stochastic nature of loads. The losses carry significance in terms of cost parameters, and this article focuses on HC investigation in terms of losses and their associated cost. The network losses followed a U-shaped trajectory with increasing PV penetration in the distribution network. In the investigated case networks, increased PV penetration reduced network costs up to around 40%, defined as a ratio to the feeding secondary transformer rating. Above 40%, the losses started to increase again and at 76–87% level, the network costs were the same as in the base cases of no PVs. This point was defined as the economical PV HC of the network. In the case of networks, this level of PV penetration did not yet lead to violations of network technical limits.


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