Numerical Study of the Thermal Efficiency of Buildings Built by Earth Blocks Stabilized by Cement

This paper deals with Numerical Study of 4-stoke, Single cylinder, Spark Ignition, Extended Expansion Lean Burn Engine. Engine processes are simulated using thermodynamic and global modeling techniques. In the simulation study following process are considered compression, combustion, and expansion. Sub-models are used to include effect due to gas exchange process, heat transfer and friction. Wiebe heat release formula was used to predict the cylinder pressure, which was used to find out the indicated work done. The heat transfer from the cylinder, friction and pumping losses also were taken into account to predict the brake mean effective pressure, brake thermal efficiency and brake specific fuel consumption. Extended Expansion Engine operates on Otto-Atkinson cycle. Late Intake Valve Closure (LIVC) technique is used to control the load. The Atkinson cycle has lager expansion ratio than compression ratio. This is achieved by increasing the geometric compression ratio and employing LIVC. Simulation result shows that there is an increase in thermal efficiency up to a certain limit of intake valve closure timing. Optimum performance is attained at 90 deg intake valve closure (IVC) timing further delaying the intake valve closure reduces the engine performance.

Download Full-text

Energy Conversion by Nanomaterial-Based Trapezoidal-Shaped Leg of Thermoelectric Generator Considering Convection Heat Transfer Effect

Journal of Energy Resources Technology ◽

10.1115/1.4042644 ◽

2019 ◽

Vol 141 (8) ◽

Cited By ~ 6

Author(s):

Abu Raihan Mohammad Siddique ◽

Franziska Kratz ◽

Shohel Mahmud ◽

Bill Van Heyst

Keyword(s):

Heat Transfer ◽

Thermoelectric Materials ◽

Thermal Efficiency ◽

Waste Heat ◽

Numerical Study ◽

Convection Heat Transfer ◽

Peltier Effect ◽

Convection Heat ◽

Cold Surface ◽

Current Output

Thermoelectric generators (TEGs) can harvest energy without any negative environmental impact using low potential sources, such as waste heat, and subsequently convert that energy into electricity. Different shaped leg geometries and nanostructured thermoelectric materials have been investigated over the last decades in order to improve the thermal efficiency of the TEGs. In this paper, a numerical study on the performance analysis of a nanomaterial-based (i.e., p-type leg composed of BiSbTe nanostructured bulk alloy and n-type leg composed of Bi2Te3 with 0.1 vol % SiC nanoparticles) trapezoidal-shaped leg geometry has been investigated considering the Seebeck effect, Peltier effect, Thomson effect, Fourier heat conduction, and surface to surrounding irreversible heat transfer loss. Different surface convection heat transfer losses (h) are considered to characterize the current output, power output, and thermal efficiency at various hot surface (TH) and cold surface (TC) temperatures. Good agreement has been achieved between the numerical and analytical results. Moreover, current numerical results are compared with previous related works. The designed nanomaterial-based TEG shows better performance in terms of output current and thermal efficiency with the thermal efficiency increasing from 7.3% to 8.7% using nanomaterial instead of traditional thermoelectric materials at h = 0 W/m2K while TH is 500 K and TC is 300 K.

Download Full-text

Numerical Study of the Thermal Efficiency of a School Building with Complex Topology for Different Orientations

Indoor and Built Environment ◽

10.1177/1420326x08099550 ◽

2009 ◽

Vol 18 (1) ◽

pp. 41-51 ◽

Cited By ~ 9

Author(s):

Eusébio Z.E. Conceição ◽

Ma Manuela J.R. Lúcio

Keyword(s):

Thermal Efficiency ◽

Numerical Study ◽

School Building ◽

Complex Topology

Download Full-text

A Numerical Study on Integral Solar Air Collector

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.860-863.146 ◽

2013 ◽

Vol 860-863 ◽

pp. 146-150

Author(s):

Fu Sheng Dong ◽

Ming Fu Hu ◽

Xiao Chun Huang

Keyword(s):

Mathematical Model ◽

Solar Radiation ◽

Thermal Efficiency ◽

Radiation Intensity ◽

Numerical Study ◽

One Dimension ◽

Inlet Temperature ◽

Solar Radiation Intensity ◽

Solar Air Collector ◽

Matlab Programming

A mathematical modeling method was devoted to study the thermal performance of integral solar air collector. A mathematical model of heat transfer was set up based on one-dimension assumptions at first, and then numerical solution was brought out by using finite-difference method under one-dimension steady heat exchange. Through the MATLAB programming, the approximate solutions for the local air temperature and thermal efficiency were obtained at the quasi-steady state. After calculation, the influence of air inlet velocity, inlet temperature, solar radiation intensity and height of flow channel on the performance of collector was analyzed. It is discovered that the mathematical model is reasonable, the thermal efficiency decreases with temperature of inlet air increasing and increases with air velocity increasing, on which the solar radiation intensity have little influence. Depth of the channel and optimum flow both have a best value.

Download Full-text

Experimental and numerical study of Interlocking Stabilized Earth Blocks mechanical behavior

Journal of Building Engineering ◽

10.1016/j.jobe.2016.06.012 ◽

2016 ◽

Vol 7 ◽

pp. 207-216 ◽

Cited By ~ 8

Author(s):

Hela Ben Ayed ◽

Oualid Limam ◽

Mohamed Aidi ◽

Ahmed Jelidi

Keyword(s):

Mechanical Behavior ◽

Numerical Study ◽

Earth Blocks

Download Full-text

A Numerical Study of NOx Reduction for a DI Diesel Engine With Complex Geometry

Journal of Energy Resources Technology ◽

10.1115/1.1627366 ◽

2004 ◽

Vol 126 (1) ◽

pp. 13-20 ◽

Cited By ~ 4

Author(s):

Renshan Liu ◽

Chao Zhang

Keyword(s):

Diesel Engine ◽

Thermal Efficiency ◽

Fuel Injection ◽

Complex Geometry ◽

Numerical Study ◽

Direct Injection ◽

Nox Reduction ◽

Geometrical Parameters ◽

Injection Timing ◽

Di Diesel Engine

A numerical study of NOx reduction for a Direct Injection (DI) Diesel engine with complex geometry, which includes intake/exhaust ports and moving valves, was carried out using the commercial computational fluid dynamics software KIVA-3v. The numerical simulations were conducted to investigate the effects of engine operating and geometrical parameters, including fuel injection timing, fuel injection duration, and piston bowl depth, on the NOx formation and the thermal efficiency of the DI Diesel engine. The tradeoff relationships between the reduction in NOx and the decrease in thermal efficiency were established.

Download Full-text