Heat exchangers are widely used in power engineering and industrial applications, many techniques such as coiled tube, surface tension devices, rough surfaces, extended surfaces have been investigated to enhancethermal performance and to minimize the cost and size of the heat exchanger equipment. One of the most important techniques is tube insert. In general,tube inserts can be classified into...

fridges are used in various industries, and heat exchanger is one of the main components of these systems; therefore, efficiency analysis of these systems is very important. in many fridges, frost over the heat exchanger tubes or pipes affects the system operation and reduces heat transfer between the refrigerant and ambient, so defrosting systems are usually used to enhance heat transfer. desi...

in this paper, the effects of input temperature and compression ratio on the net output work and efficiency of the air standard cycles, i.e. atkinson cycle, diesel cycle and otto cycle are analyzed. we assumed that the compression and power processes are adiabatic and reversible and any convective, conductive and radiative heat transfer to cylinder wall during the heat rejection process may be ...

Heat transfer fluids have inherently low thermal conductivity that greatly limits the heat exchange efficiency. While the effectiveness of extending surfaces and redesigning heat exchange equipments to increase the heat transfer rate has reached a limit, many research activities have been carried out attempting to improve the thermal transport properties of the fluids by adding more thermally c...

    Given the need to increase the efficiency of heat transfer in thermal systems, especially systems using nanofluids in microscale and nanoscale heat transfer equipment ideas to improve their performance is very good.In present study, the flow and heat transfer of Water-Cu nanofluid in micro-tube with slip regime with constant wall heat flux numerically simulated with low Reynolds numbers. Sl...

The mathematical model to predict the performance and the exergetic efficiency in a multi-effect desalination system with thermal vapor compression (MED-TVC system) has been presented. The energy and the concentration conservation law were developed for each effect, considering the boiling point elevation and the various thermodynamic losses by developing the mathematical models. These analyses...

A numerical study has been conducted to investigate the influence of fin pitch and relative humidity on the heat transfer performance of the fin-and-tube heat exchangers having plain fin geometry under dehumidifying conditions. The analysis is done using the ratio between the heat transfer coefficients in totally wet conditions and those in totally dry conditions using the appropriate correlati...

Heat transfer phenomena of flat plate solar collector filled with different nanofluids has been investigated numerically. Galerkin’s Finite Element Method is used to solve the problem. Heat transfer rate, average bulk temperature, average sub-domain velocity, outlet temperature, thermal efficiency, mean entropy generation and Bejan number has been investigated by varying the solid nanoparticle ...

Air compressor is the critical part of a Compressed Air Energy Storage (CAES) system. Efficient and fast compression of air from ambient to a pressure ratio of 200-300 is a challenging problem due to the trade-off between efficiency and power density. Compression efficiency is mainly affected by the amount of heat transfer between the air and its surrounding during the compression. One way to i...