scholarly journals Reducing The Operating Costs Of An Apartment Building

2015 ◽  
Vol 23 (3) ◽  
pp. 28-32
Author(s):  
Ján Takács ◽  
Lukáš Rácz
Keyword(s):  
Heat Transfer ◽  
Mechanical Energy ◽  
Heating System ◽  
Operating Costs ◽  
Apartment Building ◽  
Heat Transfer Medium ◽  
Circulation Pump ◽  
Pressure Losses ◽  
Static Energy ◽  
Mechanical Devices

Abstract Circulation pumps are mechanical devices, which are used to create the overpressure required for the transportation of a heat-transfer medium in heating technology as well as in other related technologies. In a circulation pump the mechanical energy generated by the drive machine – an electric motor is transformed to hydraulic energy, which consists of kinetic and static energy. In the pipeline of a heating system circulation pumps represent a source of hydraulic energy (positive differential pressure), which is consumed to transport the heat-transfer medium. During the flow, the heat-transfer medium puts up resistance to the so-called passive resistors, which consist of pressure losses from friction in the pipes and pressure losses due to local resistance. In this article the authors analyze the effect of a circulation pump on the operating costs in an apartment building. Different types of circulating pumps, ranging from the most unfavorable to the optimal, were selected.

scholarly journals Costs Analysis of Circulation Pumps for Heating of Residential Building

2017 ◽  
Vol 62 (1) ◽  
pp. 10
Author(s):  
Ján Takács ◽  
Zuzana Straková ◽  
Lukáš Rácz
Keyword(s):  
Heat Transfer ◽  
Mechanical Energy ◽  
Residential Building ◽  
Heating System ◽  
Heat Transfer Medium ◽  
Pressure Losses ◽  
Static Energy ◽  
Mechanical Devices ◽  
Heating Technology

Circulation pumps are mechanical devices, which are used to create the overpressure required for the transportation of a heat-transfer medium in heating technology as well as in other related technologies. In a circulation pump the mechanical energy generated by the drive machine – an electric motor - is transformed to hydraulic energy, which consists of kinetic and static energy. In the pipeline of a heating system circulation pumps represent a source of hydraulic energy (positive differential pressure), which is consumed to transport the heat-transfer medium. During the flow, the heat-transfer medium puts up resistance to the so-called passive resistors, which consist of pressure losses from friction in the pipes and pressure losses due to local resistance.In this article the authors describe the research, which is based on a case study. They analyze the effect of a circulation pumps on the investments and operating costs in a residential building. Different types of circulation pumps, ranging from the most unfavorable to the optimal, were selected.

PRESSURE LOSSES AND HEAT TRANSFER FOR FLOW OF DRAG REDUCING SURFACTANT SOLUTIONS IN PIPES AND FITTINGS

Equipment ◽  
2006 ◽  
Author(s):  
J. Sestak ◽  
V. Mik ◽  
J. Myska ◽  
M. Dostal ◽  
L. Mihalka
Keyword(s):  
Heat Transfer ◽  
Pressure Losses ◽  
Surfactant Solutions

scholarly journals Efficiency Improvement of Miniaturized Heat Exchangers

Fluids ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 25
Author(s):  
Iris Gerken ◽  
Thomas Wetzel ◽  
Jürgen J. Brandner
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Heat Exchangers ◽  
Assessment Method ◽  
Flow Path ◽  
Transfer Enhancement ◽  
Pressure Losses ◽  
Pin Fin ◽  
Additional Pressure ◽  
The Impact

Micro heat exchangers have been revealed to be efficient devices for improved heat transfer due to short heat transfer distances and increased surface-to-volume ratios. Further augmentation of the heat transfer behaviour within microstructured devices can be achieved with heat transfer enhancement techniques, and more precisely for this study, with passive enhancement techniques. Pin fin geometries influence the flow path and, therefore, were chosen as the option for further improvement of the heat transfer performance. The augmentation of heat transfer with micro heat exchangers was performed with the consideration of an improved heat transfer behaviour, and with additional pressure losses due to the change of flow path (pin fin geometries). To capture the impact of the heat transfer, as well as the impact of additional pressure losses, an assessment method should be considered. The overall exergy loss method can be applied to micro heat exchangers, and serves as a simple assessment for characterization. Experimental investigations with micro heat exchanger structures were performed to evaluate the assessment method and its importance. The heat transfer enhancement was experimentally investigated with microstructured pin fin geometries to understand the impact on pressure loss behaviour with air.

scholarly journals Cooling Performance Analysis of Outside Fins of the Closed Circuit Axial Piston Transmission

Machines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 17
Author(s):  
Chen Yang ◽  
Long-jie Yu ◽  
Junhui Zhang ◽  
Jin-yuan Qian
Keyword(s):  
Heat Transfer ◽  
Heat Dissipation ◽  
Mechanical Energy ◽  
Closed Circuit ◽  
Moderate Increase ◽  
Frictional Loss ◽  
Fin Thickness ◽  
Axial Piston ◽  
Positive Effect ◽  
Peak Value

Realizing conversion between fluid power and mechanical energy, the closed circuit axial piston transmission (CCAPT) plays a vital and indispensable role in miscellaneous industries. The frictional loss and leakage loss inside the system give rise to the inevitable temperature rise. In order to prolong the life of the device, a cooling structure on the outside of the CCAPT is designed for promoting heat dissipation. Based on the relevant heat transfer law and the temperature distribution of internal machinery elements, a spiral fin structure is designed at the shell side. With the help of numerical simulation, the effects of fin height, fin pitch, and fin thickness on the thermal performance are studied. The flow field and temperature field on the outside of the fin structure are obtained as a guidance for enhancing heat dissipation effect. Results indicate that the area of rotating elements tend to accumulate heat, where more attention should be paid for a better cooling effect. In addition to this, a moderate increase of fin height, fin pitch and fin thickness has a positive effect on heat transfer enhancement. The peak value of Nusselt number is obtained with a fin height of 7.5 mm, which is about 2.09 times that of the condition without the fin structure. An increase in fin pitch improves both heat transfer performance and comprehensive performance at the same. When fin pitch is 30 mm, Nusselt numberincreases 104% over the original condition.

Analysis of a Virtual Prototype First-Stage Rotor Blade Using Integrated Computer-Based Design Tools

2006 ◽  
Author(s):  
Michel Arnal ◽  
Christian Precht ◽  
Thomas Sprunk ◽  
Tobias Danninger ◽  
John Stokes
Keyword(s):  
Heat Transfer ◽  
Gas Flow ◽  
Thermal Loading ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Life Assessment ◽  
Element Analysis ◽  
Pressure Losses ◽  
Cooling Channels ◽  
Internally Cooled

The present paper outlines a practical methodology for improved virtual prototyping, using as an example, the recently re-engineered, internally-cooled 1st stage blade of a 40 MW industrial gas turbine. Using the full 3-D CAD model of the blade, a CFD simulation that includes the hot gas flow around the blade, conjugate heat transfer from the fluid to the solid at the blade surface, heat conduction through the solid, and the coolant flow in the plenum is performed. The pressure losses through and heat transfer to the cooling channels inside the airfoil are captured with a 1-D code and the 1-D results are linked to the three-dimensional CFD analysis. The resultant three-dimensional temperature distribution through the blade provides the required thermal loading for the subsequent structural finite element analysis. The results of this analysis include the thermo-mechanical stress distribution, which is the basis for blade life assessment.

Numerical Modeling of Heat Transfer and Pressure Losses for Uncooled Gas Turbine Blade Tip: Effect of Tip Clearance and Tip Geometry

2007 ◽  
Author(s):  
Lamyaa A. El-Gabry
Keyword(s):  
Heat Transfer ◽  
Mach Number ◽  
Gas Turbine ◽  
Computational Study ◽  
Numerical Models ◽  
Pressure Ratio ◽  
Tip Clearance ◽  
Pressure Losses ◽  
Blade Tip ◽  
Exit Mach Number

A computational study has been performed to predict the heat transfer distribution on the blade tip surface for a representative gas turbine first stage blade. CFD predictions of blade tip heat transfer are compared to test measurements taken in a linear cascade, when available. The blade geometry has an inlet Mach number of 0.3 and an exit Mach number of 0.75, pressure ratio of 1.5, exit Reynolds number based on axial chord of 2.57×106, and total turning of 110 deg. Three blade tip configurations were considered; they are flat tip, a full perimeter squealer, and an offset squealer where the rim is offset to the interior of the tip perimeter. These three tip geometries were modeled at three tip clearances of 1.25, 2.0, and 2.75% of blade span. The tip heat transfer results of the numerical models agree fairly well with the data and are comparable to other CFD predictions in the open literature.

Influence of Covering Layer on Surface Temperature of Floor Radiant Heating System

2012 ◽  
Vol 204-208 ◽  
pp. 4260-4263 ◽  
Author(s):  
Hai Qian Zhao ◽  
Zhong Hua Wang ◽  
Lan Shuang Zhang
Keyword(s):  
Heat Transfer ◽  
Surface Temperature ◽  
Heating System ◽  
Radiant Heating ◽  
Wooden Floor ◽  
Surface Temperature Distribution ◽  
Covering Layer ◽  
Floor Surface ◽  
Space Saving ◽  
Cover Material

Floor radiant heating system has many advantages, energy and space saving, for example. The radiant floor is the radiator of floor radiant heating system, and its thermal parameters influence surface temperature distribution and comfort. In this paper, mathematical model of heat exchange coil under floor was established, and boundary heat transfer conditions were given. Based on these, surface temperature of different covering layer was calculated. According to the results, using different covering layer, the floor surface temperature has a great difference. Using wooden floor as cover material, the floor surface temperature is more moderate and uniform.

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