scholarly journals ENERGY, EXERGY AND THERMOECONOMIC ANALYSİS OF A NATURAL GAS ASSİSTED GEOTHERMAL CENTRAL HEATING SYSTEM

2021 ◽  
pp. 757-776
Author(s):  
Nurettin YAMANKARADENİZ ◽  
Orhan ŞAHMERDAN
Keyword(s):  
Natural Gas ◽  
Heating System ◽  
Central Heating

scholarly journals Failure Analysis of Premature Corrosion of HF Seam-Welded Steel Pipe in Central Heating System

2021 ◽  
Author(s):  
Dorota Tyrala ◽  
Bogdan Pawlowski
Keyword(s):  
High Frequency ◽  
Energy Dispersive Spectrometry ◽  
Weld Line ◽  
Welding Process ◽  
Heating System ◽  
Bond Line ◽  
Steel Pipe ◽  
Huge Number ◽  
Welded Steel ◽  
Central Heating

AbstractPremature corrosion in the form of longitudinal cracking in a high-frequency (HF) induction seam-welded steel pipe occurred after just 24 months in service. The failed pipe was investigated to reveal the main cause of its failure, and the results of microstructural examinations (light optical microscopy, scanning electron microscopy with energy-dispersive spectrometry) suggest that the failure resulted from an HF induction welding process defect—a so-called cast weld, that is, a huge number of iron oxides in the weld line caused by insufficient ejection of the molten metal from the bond line.

Atverčiant primirštą Lietuvos kultūros puslapį: Vilniaus modernizmo atspindžiai pavelde

2021 ◽  
pp. 213-229
Author(s):  
Edita Povilaitytė-Leliugienė
Keyword(s):  
Interwar Period ◽  
New Technologies ◽  
Heating System ◽  
Modern Architecture ◽  
Heritage Preservation ◽  
Urban Structures ◽  
General Law ◽  
Central Heating ◽  
Heritage Buildings ◽  
Modern Technologies

The analyses of interwar Vilnius heritage preservation, research, and maintenance concentrated mostly on discussions about the general law, state tendency, and case studies of good and bad practices. However, the more modern heritage preservation, research, or maintenance theories and aspects during the interwar period were neglected. Therefore, this article aims to analyse if modern technologies, ideas, and methods in the heritage research and maintenance (mostly in the reconstructions and adaptation of heritage buildings for new purposes) projects were adapted or not in interwar Vilnius. According to this aim, the article analyses a few heritage maintenance works and emphasises how architects used new technologies, modern architecture details, and ideas in the heritage maintenance projects and their realisation. Technologies as central heating system, electrification, canalisation, toilets, or bright interiors, wide air-spaces were inseparable from modernism perspective. The architecture of buildings and urban structures were modernised and improved for better living quality. Also, ideas and technologies did not avoid the heritage objects, especially civil buildings as Vilnius Town Hall, squares as Cathedral square, defensive heritage object as Vilnius Upper Castle. However, the analysis maintains that modern technologies were used moderately and kept a respectful tone with the authentic heritage, whole complex, and elements.

Thermodynamic Analysis of a Central Heating System Combing the Urban Heat Network With Geothermal Energy

2013 ◽  
Author(s):  
Xiao Wang ◽  
Lin Fu ◽  
Xiling Zhao ◽  
Hua Liu
Keyword(s):  
Heat Exchanger ◽  
Heat Exchange ◽  
Heat Pump ◽  
Geothermal Energy ◽  
Heating System ◽  
Heat Network ◽  
Pump System ◽  
Absorption Heat Pump ◽  
Central Heating ◽  
Exchange Unit

In recent years, with the continuous urban expansion, the central heating sources are commonly insufficient in the areas of Northern China. Besides, the increasing heat transfer temperature difference results in more and more exergy loss between the primary heat network and the secondary heat network. This paper introduces a new central heating system which combines the urban heat network with geothermal energy (CHSCHNGE). In this system, the absorption heat exchange unit, which is composed of an absorption heat pump and a water to water heat exchanger, is as alternative to the conventional water to water heat exchanger at the heat exchange station, and the doing work ability of the primary heat network is utilized to drive the absorption heat pump to extract the shallow geothermal energy. In this way, the heat supply ability of the system will be increased with fewer additional energy consumptions. Since the water after driving the absorption heat pump has high temperature, it can continue to heat the supply water coming from the absorption heat pump. As a result, the water of the primary heat network will be stepped cooled and the exergy loss will be reduced. In this study, the performance of the system is simulated based on the mathematical models of the heat source, the absorption heat exchange unit, the ground heat exchanger and the room. The thermodynamic analyses are performed for three systems and the energy efficiency and exergy efficiency are compared. The results show that (a) the COP of the absorption heat exchange unit is 1.25 and the heating capacity of the system increases by 25%, which can effectively reduce the requirements of central heating sources; (b) the PER of the system increases 14.4% more than that of the conventional co-generation central heating system and 54.1% more than that of the ground source heat pump system; (c) the exergy efficiency of the CHSCHNGE is 17.6% higher than that of the conventional co-generation central heating system and 45.6% higher than that of the ground source heat pump system.

scholarly journals EVALUATION OF COMBINED PRODUCTION OF HEAT AND ELECTRICITY ON THE COGENERATION UNIT

2021 ◽  
Vol 2021 (6) ◽  
pp. 5312-5316
Author(s):  
MIROSLAV RIMAR ◽  
◽  
MARCEL FEDA ◽  
ANDRII KULIKOV ◽  
MILAN ABRAHAM ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Natural Environment ◽  
Energy Production ◽  
Renewable Energy Sources ◽  
Winter Season ◽  
Main Idea ◽  
Heating System ◽  
Energy Sources ◽  
Central Heating

The purpose of currently contribution is to analyse and compare effectivity of cogeneration unit in each summer and winter season. The main idea of combined heat and energy production is to reduce usage of primary fuels and with that connected reduction of pollutions due to the integration of renewable energy sources and with regard to the natural environment. Presented contribution is dedicated on issue on the operation of a cogeneration unit integrated in central heating system.

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 Autonomous heating system during transformation of thermal energy formed in server stations

2021 ◽  
Vol 25 (1) ◽  
pp. 130-139
Author(s):  
Е.G. Komarov ◽  
◽  
V.V. Lozovetsky ◽  
V.V. Lebedev ◽  
V.M. Cherkina ◽  
...  
Keyword(s):  
Heat Pump ◽  
Thermal Energy ◽  
Air Conditioning ◽  
Heating System ◽  
Thermal Emissions ◽  
Power Resources ◽  
Central Heating ◽  
Exchange Processes ◽  
Material Power ◽  
The Mathematical Model

Results of design modeling of air-conditioning and central air of premises of server stations are presented. The estimation of thermal balance of typical server station is made. The potential of thermal energy which can be used is estimated it is useful for needs of central heating, to save power resources, and not to pollute environment thermal emissions. The detailed analysis of components of is material-power balance is made. The mathematical model of central air is developed for these purposes. Analysis problems of the heat substances exchange processes, the drainage of air connected with processes, occurring at its cooling are considered. The designing and operation problems interfaced with the heat substances exchange in air coolers are considered. The heat pump scheme of system is offered the central heating, utilizing warmly server station at air conditioning indoors. The model is offered and results of optimization of parameters heat pump schemes are considered. Results can be applied at designing of central airs of premises of server stations with passing recycling of thermal emissions for needs of central heating.

scholarly journals Calculation Of Heat Loss Through The Pipes Of The Interior Central Heating System

2015 ◽  
Vol 5 (2) ◽  
pp. 29-36 ◽  
Author(s):  
I. Giurca
Keyword(s):  
Heat Loss ◽  
Heating System ◽  
Building Energy ◽  
Local Heat ◽  
Heat Losses ◽  
Energy Audit ◽  
Heating Systems ◽  
Central Heating ◽  
Calculation Methodology

Abstract The article presents aspects related to the calculation of heat loss through the pipes of the interior central heating system. The purpose of the article is to detail the local heat losses in case of central heating systems. Based on the conclusions of the article, we propose the modification of the calculation methodology related to the building energy audit.

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