Heat Transfer, Combustion Commons^™

Water-Heated Maisotsenko Cycle Humidifiers: A Component-Level Study On Evaporation And Exit Brine Concentration, Omar Abdulfattah Farag Omar A. Farag

Renewable Mechanical Energy

Maisotsenko-cycle (M-cycle) Heat-and-Mass Exchangers (HMXs) are usually assessed as part of complete cooling or desalination systems, which makes the behaviour of the humidifier itself difficult to distinguish. Here, a validated model is used to examine a water-heated M-cycle humidifier as an independent component. Inlet saline-water temperature, ambient temperature, Relative Humidity (RH), and water-to-air Mass-flow Ratio (MR) were varied, and performance was described by Water Evaporation Rate (WER), outlet-air specific humidity, and outlet brine salinity. Water heating and a larger MR produced the strongest increase in moisture addition because they maintained a warmer water film and greater transfer potential. At fixed …

Experimental Study On The Effect Of Micro Concentrations Of Hybrid Nanofluids Through Microchannel Heat Sinks, Mohamed Salaheldin Elsherbiny, Moustafa Ali, Moatsem Shahin, Mahmoud El-Kady

Renewable Mechanical Energy

The current study examines the convective heat transfer coefficient experimentally. It assesses the performance of Al2O3, CuO, ZnO, and Ag/ distilled water nanofluids up to a tetra level of hybridization utilized in microprocessor cooling systems equipped with MCHS. An equal ratio of 50%, 33.3%, and 25% for di-, tri-, and tetra-nanofluids, respectively, with a focus on micro-volume fraction 0.025% and comparing it with 0.05%. Operating conditions were as follows: heat loading from 136.4 up to 196.4 watts; and flow rate from 0.35 up to 0.5 LPM. The findings showed that all types of mono nanofluids showed an increase in Nu …

The Performance Response Of A Heat Pipe Evacuated Tube Solar Collector Using Mgo/Mwcnt Hybrid Nanofluid As A Working Fluid, Ahmed A. Abdel-Rehim, Shady Henein

Mechanical Engineering

Utilizing a hybrid nanofluid is a promising solution for enhancing the thermal performance of the solar collector in a sustainable manner. In the present work, the effect of using magnesium oxide/multi-walled carbon nanotubes (MgO/MWCNT) hybrid nanofluid on the thermal performance of the evacuated tube solar collector is experimentally investigated. Four different weight ratios of (80:20), (70:30), (60:40), and (50:50) are used for a hybrid of MgO with MWCNTs in a water base, respectively. The experiments are performed at a 0.02% particle concentration and at various volume flow rates ranging from 1 to 3 L/min. The results show an enhancement in …

Responses Of An Axially Rotated Tube Versus Twisted Tube Design As Two Solutions To Enhance The Thermal Performance Under A Non-Uniform Heat Flux Condition: A Numerical Study, Andrew S. Tanious, Ahmed A. Abdel-Rehim, Ahmed A. Attia

Mechanical Engineering

Enhancement of heat transfer in tubes exposed to non-uniform heat flux applications is a key factor in increasing such applications' efficiency.

In the present study, heat transfer in an axially rotating pipe with concentrated heat flux at the lower section of the pipe is numerically investigated and compared to the twisting technique in such applications. The effects of pipe’s length (1, 2, and 3 m) and rotation rate (N = 0–10.5), which is the ratio between the rotational and axial Reynold’s numbers, are studied numerically using ANSYS Fluent while the effect of the twist ratio (S = 0.1–1m) is studied …

Performance And Economical Analysis Of Different Insulating Materials Used To Reduce The Heat Load Of An Existing Residential Building, Radwa A. El-Awadly, Ahmed A. Abdel-Rehim

Mechanical Engineering

The energy consumption from the residential sector is an important element which has an impact on the total energy consumption in any country. The heating and air conditioning loads can be reduced through many means. Using thermal insulation in buildings does not only contribute in reducing the required air conditioning system size, but also in reducing the annual energy cost for the whole building. In this case, the energy saving varies according to the building type, the climatic conditions at which the building is located as well as the type of the insulating material used. In the present study, an …

Numerical Investigation Of The Thermal Performance Of An Axially Rotating Internally Finned Receiver Tube Of A Parabolic Trough Concentrator, Andrew S. Tanious,, Ahmed A. Abdel-Rehim

Mechanical Engineering

Enhancement of the thermal performance of the parabolic trough receiver tube is one of the approaches to energy sustainability. In the present work, the thermal performance of an axially rotating receiver tube equipped with internal flat longitudinal fins is studied. The effects of both the fin height and the rate of axial rotation are investigated at low values of axial Reynold’s number. The numerical analysis is held at various rotation rates using ANSYS Fluent. The numerical findings showed that the effect of the axial rotation on the internally finned receiver tube is not significant yet negative where a maximum reduction …

Energetic And Exergetic Analysis Of A Heat Pipe Evacuated Tube Solar Collector Using Mwcnt/Water Nanofluid, Mahmoud Eltaweel, Ahmed A. Abdel-Rehim

Mechanical Engineering

Increasing the energy demand and the limited availability of conventional energy sources are the main challenges to secure the human future. Solar energy is an attractive source of energy to ensure the sustainability of energy in this world for now and for the future. Evacuated tube solar collector is a solar thermal collector mostly used for domestic applications. The replacement of the working fluid with nanofluid can enhance the heat transfer even for low temperature applications. The effect of multi-walled carbon nanotubes and water nanofluid as working fluid in evacuated tube solar collector is used to experimentally investigate the energy …