Cold production reducing energy costs using ozone-friendly refrigerants

The article considers ways to reduce energy costs in the cold using ozone-safe refrigerants production. In this case, it is necessary to include an air-cooled heat exchanger-pre-condenser in the technological scheme of refrigeration. The conditions for the pre-capacitor for a certain performance selection are formulated. The results of the presented calculations prove a decrease in the annual energy consumption for cold production in comparison with the technological scheme with external cooling and a cascade system. The energy consumption reducing principle of the installation due to the air pre-condenser can also be realized by installing a heat-exchanger on the discharge of low-temperature compressors to heat water for the enterprise needs, receiving free heat energy all year round.

Experimental Study for Counter to Cross Flow Air Cooled Heat Exchanger in Concentric Tube using Rectangular Copper Fins Spacing with Internal Spiral Grooving

In this manuscript we have presented eight variation of Air-Cooled Heat Exchanger (ACHE) design with internal spiral grooving, all of them are having variable number of rectangular copper fins with different distances between the fins. In the proposed design we get the value of heat transfer rate of a counter to cross flow ACHE is 7833.77 watt, 4068.13 watt, 2736.95 watt, 2161.49 watt, 1802.89 watt, 1546.44 watt, 1336.51 watt and 1165.74 watt in natural convection (without fan) for 0.5 cm, 1.0 cm, 1.5 cm, 2.0 cm, 2.5 cm, 3.0 cm, 3.5 cm and 4.0 cm respectively. Then again, value of rate of heat transfer in forced convection (with fan) are 8007.46 watt, 4084.81 watt, 2754.69 watt, 2205.98 watt, 1809.24 watt, 1555.39 watt, 1352.88 watt and 1172.78 watt for 0.5 cm, 1.0 cm, 1.5cm, 2.0 cm, 2.5 cm, 3.0 cm, 3.5 cm and 4.0 cm respectively.

Experimental Study of Counter to Cross Flow Air-Cooled Heat Exchanger using different Fins pitch with Internal Circular Grooving

In this manuscript we have presented seven variation of Air-Cooled Heat Exchanger (ACHE) design with internal grooving annular tube, all of them are having variable number of aluminum rectangular fins with different distances between the fins. In the proposed design we get the value of heat transfer rate of a counter to cross flow ACHE is 7062.95 watt, 3969.78 watt, 2724.15 watt, 2149.25 watt, 1785.03 watt, 1533.43 watt, and 1325.34 watt in natural convection (without fan) for 5 mm, 10 mm, 15mm, 20 mm, 25 mm, 30 mm and 35 mm respectively. On the other hand the value of heat transfer rate in forced convection (with fan) are 7100.40 watt, 3995.30 watt, 2740.54 watt, 2162.26 watt, 17897.63 watt, 1540.00 watt, and 1331.60 watt for 5 mm, 10 mm, 15mm, 20 mm, 25 mm, 30 mm and 35 mm respectively.

Numerical Simulation and Field Synergy Analysis of IGBT Air-Cooled Heat Exchanger for EMUs

In view of the heat transfer and ventilation characteristics of the Insulated Gate Bipolar Transistor (IGBT) in the Electric Multiple Unit (EMU), the authors aim to improve the traditional fin structure of the air-cooled heat exchanger (ACHE) and propose the use of corrugated fin structure. Using the computational fluid dynamics (CFD) technology, the ACHE with new fin structure was numerically simulated, and the temperature field, velocity field and pressure field at different fin corrugation angles and the synergy between the fields were analyzed. The results show that the improved fin structure can make the fluid flow in a corrugated flow channel, effectively increase the flow distance, and thus significantly enhance the turbulence performance of the fluid in the ACHE; the fin corrugation angle of 120 degrees is the key design point; compared with the traditional fin structure, the new fin structure improves the synergy between the various fields and increases the heat exchange efficiency. The research findings provide new ideas for the design of this type of ACHE.