scholarly journals INVESTIGATION OF THE UNCERTAINTY VALUE AT MEASURING THE TEMPERATURE OF THE COOLANT IN THE PIPELINES WITH OUTSIDE SURFACE MOUNTED TEMPERATURE SENSORS

2021 ◽  
pp. 42-49
Author(s):  
Petro Golovachev ◽  
Ivan Korobko ◽  
Vitalii Krotevich
Keyword(s):  
Residential Buildings ◽  
Field Tests ◽  
District Heating ◽  
Temperature Sensors ◽  
Heat Fluxes ◽  
Coolant Temperature ◽  
Heating Systems ◽  
Average Temperature ◽  
Heat Meters

During performing technological and production processes and monitoring the modes of their operation, the problem of determining the temperature of various media transported through pipelines is solved without incut temperature sensors (TS) in them, i.e. with using outside surface mounted TS (SMTS). This method is allowing to measure mechanical values at technological processes without structure broken and without influence to physicochemical properties of measured media. Using of SMTS possible to register heat losses on sections of heating mains, pollution degree of pipelines internal walls, to control serviceability of measurement channels of temperature of the coolant in heat meters, etc. In the article authors presents results of research the uncertainty values for measuring of the coolant temperature in heating systems pipelines under different modes of its flow. First of all, the uncertainty value of the measurements results was estimated, which was determined by the results of the study for the calculation model and field tests at existing district heating systems. Emphasis is paid on estimating the difference between the registration of temperature in the middle of the pipeline, determined by mortise transducers and the temperature measured by outside surface mounted temperature transducers, taking into account the temperature gradient across the pipeline and the quality of its insulation. It is determined that: the temperature measured by temperature transducers on the surface of the pipeline at different points of its perimeter, with proper installation and sufficient thermal insulation does not depend on their location; the average temperature on the surface of the pipeline, measured using the developed method of installation of PT, slightly differs (ΔT ≈- 0.3⁰C) from the average temperature of the coolant in the middle of the flow; temperature transducers have high reproducibility of measurements and small difference in readings between channels at parallel measurements (»0,03⁰С). It is substantiated that high metrological performances of temperature transducers allow to use them for solving other tasks: measuring the distribution of heat fluxes in heating systems of residential buildings to perform hydraulic balancing of heating systems and increase their efficiency; estimate of contamination of pipelines and heat exchange equipment to determine the need for their washing; determination of thermal resistance of  buildings protective structures to assess their energy efficiency; determination of large pumps efficiency by calorimetric method; checking the correct of operation the temperature measuring channels of heat meters and cold meters; in other technology areas where measurements of small temperature differences with high accuracy are required.

scholarly journals METHODOLOGY OF THE PRIMARY DATA RECONSTRUCTION OF SINGLE PIPE HEATING SYSTEMS/VIENVAMZDŽIŲ ŠILDYMO SISTEMŲ PIRMINIŲ DUOMENŲ NUSTATYMO METODIKA

1999 ◽  
Vol 5 (5) ◽  
pp. 318-322
Author(s):  
Edvardas Tuomas ◽  
Saulius Neverbickas
Keyword(s):  
World War Ii ◽  
District Heating ◽  
Heating System ◽  
Heat Fluxes ◽  
Primary Data ◽  
Complex Coefficient ◽  
Heating Systems ◽  
Pipe System ◽  
Central Heating ◽  
Single Pipe

The majority of dwellings in Lithuania are situated in blocks of flats. The dwellings were built after World War II and they are heated by single pipe central heating systems, connected to district heating. The dwellers are not quite satisfied with such a heating system and try to improve it, but do that in a wrong way, by increasing the surface of radiators. Such means lead to violation of thermal regime and comfort conditions for other dwellers. There exists sometimes the necessity of reconstructing premises and together—the heating system. During the reconstruction the primary heat fluxes from radiators should be known, but very often such data are lost and only the size of radiators (number of sections) are known. To reconstruct the required primary data for single pipe systems is complicated because the temperatures of inlet and outlet water for radiators are unknown. In this article the methodology is proposed how to perform the calculations leading to the required data. The aim of calculations is the establishment of heat fluxes from each radiator connected to the riser. Heat flux from radiator can be calculated according the formula (1) but the complex coefficient is unknown. It could be found from formulae (2) but some magnitudes are unknown. According to the proposed methodology the values of unknown magnitudes are taken approximately and calculations are performed with iterations. In such a way the flow rate of water in riser is established from formula (3), which is the same for each radiator (the property of single pipe system). From formulas (3) and (4) an equation is produced (5), and is used for calculations of unknown temperatures. The equation (6) is used for calculation of heat fluxes from radiators. To carry out the above-mentioned calculations without computer practically is impossible due to many cycles of iteration. The programme was prepared to make easy all these calculations. The scheme of algorithm of programme is given in Fig 1. An example of calculation is given in this article. Calculations were fulfilled by newly created programme. The riser chosen for calculation is shown in Fig 2. The results of calculation are given in Table 1. The table shows that according to the proposed methodology the programme based on it can be used for reconstruction of primary data of single pipe heating systems successfully.

scholarly journals Application of Neural Networks for Control of District Heating \ Wykorzystanie Sieci Neuronowych Do Regulacji W Ciepłownictwie

2010 ◽  
Vol 56 (3) ◽  
pp. 219-238 ◽  
Author(s):  
W.J. Chmielnicki
Keyword(s):  
Neural Networks ◽  
Residential Buildings ◽  
District Heating ◽  
Heating System ◽  
Hot Water ◽  
System Control ◽  
Heating Systems ◽  
Quality Of Control ◽  
Building Maintenance ◽  
Non Linear

Abstract The annual usage of heat for the demand of heating systems in municipal sector has been estimated as about 650PJ. It is mostly addressed for the demand of central heating systems and hot water consumption. The mode of adopted solutions concerning regulation and control, as well as energy management system, essentially influence its consumption. In the case of residential buildings, the costs of energy constitute the greatest share related to the total cost of building maintenance. Providing buildings with modern digital systems for control and regulation of heating installations is a basic condition enabling their rational usage. In currently employed solutions, algorithms PI or PID are usually applied. However, due to the non-linear properties of heating control systems, they do not secure proper quality. The sequences are often unstable and major control deviations occur. The application of neural networks is an alternative solution to those presently employed. They are especially recommended for adaptive control of non-stationary systems. Such cases occur in heating objects since they demonstrate non-linear properties with a great range of variability of parameters; this especially refers to district heating equipped with flux-through heat exchangers. In this paper, a compile model of heating system control aided by neural networks is presented. The results of the investigation clearly prove the usefulness of such solutions, cause the quality of control is much better than that one applied in traditional systems. Presently, works on the implementation of the proposed solutions are under way.

scholarly journals Determination of an Effective Heating Radius in District Heating Systems in terms of Reliability

2021 ◽  
pp. 54-62
Author(s):  
V. Stennikov ◽  
E. Mednikova ◽  
I. Postnikov
Keyword(s):  
Heat Supply ◽  
District Heating ◽  
Paper Briefly ◽  
Heating Systems ◽  
Reliability Indices ◽  
Heating Source ◽  
Practical Research ◽  
District Heating Systems ◽  
Source Operation

The paper presents a method developed to determine an effective heating radius (EHR) in district heating systems (DHSs) in terms of reliable heat supply to consumers. The search for EHR for various heating mains from the considered district heating source in DHS involves identifying heat source operation zones in various city areas. At the same time, apart from the search for EHR, the nodal reliability indices are estimated for each consumer and then used (if necessary) to adjust the obtained EHR. The paper briefly discusses some of the practical research results.

scholarly journals Cost-optimal energy retrofit for Serbian residential buildings connected to district heating systems

2019 ◽  
Vol 23 (Suppl. 5) ◽  
pp. 1707-1717 ◽  
Author(s):  
Mladen Stojiljkovic ◽  
Mirko Stojiljkovic ◽  
Marko Ignjatovic ◽  
Goran Vuckovic
Keyword(s):  
Residential Buildings ◽  
District Heating ◽  
Primary Energy ◽  
Primary Energy Consumption ◽  
Optimal Solutions ◽  
Heating Systems ◽  
Energy Retrofit ◽  
Global Cost ◽  
District Heating Systems ◽  
Cost Optimality

Buildings are significant energy consumers and provide a notable potential to reduce primary energy consumption and increase energy efficiency. Cost-effectiveness of energy efficiency projects is of crucial importance for their implementation. Cost-optimality of different packages of energy retrofit measures is studied across the EU, but Serbia mostly lacks such information. This paper analyzes cost-optimal solutions for Serbian residential buildings connected to district heating systems, considering three different scenarios related to the economic input parameters. Additionally, it considers the potential for primary energy savings beyond cost-optimality and associated costs. The optimal solutions, that correspond to minimal global cost or minimal primary energy consumption, are determined as the results of the combinatorial optimization problems. These problems are solved using the genetic algorithm and local search. The results are compared against the ones obtained with the sensitivity analysis. The global cost can be reduced by 8-43% in the cases of cost-optimal solutions, simultaneously saving 30-76% of primary energy. The potential to save primary energy is higher - it exceeds 70% in all the analyzed cases, but also requires higher global cost, sometimes larger than in the absence of the retrofit. The paper also emphasizes high dependencies of the results on very uncertain economic inputs.

scholarly journals Hydraulic Calculation of Copper Pipelines for Heating and Internal Gas Supply Systems

2018 ◽  
Vol 17 (6) ◽  
pp. 508-514
Author(s):  
M. A. Rutkowski ◽  
A. S. Shybeka ◽  
K. I. Halynia
Keyword(s):  
Pressure Loss ◽  
Theoretical Calculations ◽  
Residential Buildings ◽  
Hydraulic Calculation ◽  
Design Standards ◽  
Heating Systems ◽  
Local Loss ◽  
Supply Systems ◽  
Gas Supply

Copper pipelines are widely used while designing modern heating systems, water and gas supply of residential buildings and these pipelines have a number of advantages in comparison with steel and plastic pipelines. The main reason for limited use of copper pipes is their cost which is practically twice as much as cost of steel pipes, and four times higher than the coat of polypropylene pipes. Modern design standards in Belarus do not contain specific requirements for calculation of copper pipelines. Therefore hydraulic calculation of heating systems has been considered and analyzed on the basis of norms of Russian Federation. The drawback of all theoretical calculations presented in Russian standards is their abstraction from general laws of fluid and gas mechanics. For this reason theoretical foundations of hydraulic calculations for all pipelines have been considered and expressions have been given for determination of pressure loss due to friction and in local loss. Main flow regimes have been considered on the basis of I. Nikuradze’s experiments in order to determine linear losses and dependences for determination of friction coefficient in laminar, transient and turbulent modes have been presented in the paper. Values of local loss coefficient for main pipeline elements are given for calculation of pressure loss and the paper also shows determination of value z with due account of equipment capacity. An analysis of nomograms presented in Russian norms and researches has been carried out; shortcomings have been revealed and the ways directed on their perfection have been found. Nomograms for calculation of specific pressure losses in heating systems and internal gas supply have been constructed on the basis of natural gas and propane with due account of dependences presented in the paper. Nomograms for finding equivalent length of a single local loss have been constructed for calculation of internal gas supply systems.

Energy Consumption and CO2 Emission of Buildings Built with Industrialized Technology: The Case of Debrecen and Future Trends

2014 ◽  
Vol 899 ◽  
pp. 16-23
Author(s):  
Tamás Csoknyai
Keyword(s):  
Energy Consumption ◽  
Residential Buildings ◽  
District Heating ◽  
Energy Performance ◽  
Future Trend ◽  
Building Stock ◽  
Heating Systems ◽  
Heat Demand ◽  
District Heating Systems ◽  
Inefficient Operation

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”.

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