Search

As per the technical evolution and latest trends taken into consideration here effectively created an advanced cooling system can be useful for industry, home, schools and colleges, hospital, factories, auditoriums, shopping malls. This system uses DC motor with following specifications. This project uses cooling tube along with condenser and inlet and out let air arrangement for cooling. This system is power optimistic and shock resistant. This system uses sprinkle arrangement of water so as to generate advance cooling. This complete system having multiple arrangements these are Air inlet and outlet arrangement, Condenser arrangement, cooling pads, cooling dome, Water dome. This complete system uses battery of 12v DC and 8 amp so complete system able to work on battery so no chances of shock and requirement of power is less. This system having some advantages i.e., Shock Resistant, Easy to use, simple arrangement, water Sprinkle arrangement, High speed cooling FAN, Minimum Use of Water, Long Life. [ABSTRACT FROM AUTHOR]

An innovative solar desalination system was designed, constructed, and tested to produce more freshwater than a conventional solar still system. The new system consists of a basin type solar still and an external condenser. The condenser itself contains finned condensing pipes and a reservoir for the cooling water. The effects number of the fins, volume of cooling water, and flow rate in the condenser on the distilled output of the proposed solar desalination system were studied. As compared to the conventional basin type solar still system, the proposed system significantly produced more freshwater when cooling water volume, cooling water flow rate, numbers of fins in the condenser were increased. Furthermore, the number of fins exerted the most significant effect on freshwater productivity. The maximum daily freshwater produced was 12,350 mL when 250 L cooling water, 400 L/h flow rate, and 80 fins on the outer surface of the condensing pipe were used, which is about 300% more than the productivity of the conventional solar still. To use this solar desalination system efficiently, it was concluded that the optimum rate of cooling water must be about 50 L/h. Moreover, the remaining water volume in the condenser must be about 79 L. [ABSTRACT FROM AUTHOR]

This paper considers the evaporation process in an evaporator-connecting tube-condenser system under conditions such that the evaporation rate is determined by the evaporation and condensation mechanisms and the hydraulic resistances of the evaporation and condensation compartments and connecting tube. We present a mathematical model and numerical simulation results that demonstrate quantitative patterns of a steady-state evaporation process in a closed evaporation-condensation system. For a particular example of selenium vacuum distillation, we have determined the evaporation coefficient of selenium from experimental data on the temperature dependences of the selenium evaporation rate and saturated vapor pressure. [ABSTRACT FROM AUTHOR]

Now-a-days fin-and-tube heat exchangers are employed in a wide variety of engineering applications such as modern heat exchangers, automotive radiators, automotive air conditioning evaporators and condensers. In order to improve the performance, further innovative designs, additional applications, and advanced geometries are expected. Researchers and academicians had been working on this topic for last few decades. A number of experimental and numerical studies have been conducted and various correlations were developed. The optimum design parameters with the maximum overall heat conductance and minimum pressure drop needs more focus and research. In this paper, different experimental/numerical studies performed are reviewed, grouped and summarized based on the types of heat exchangers, heat transfer and pressure drop performance, effects of geometrical parameters under different flow conditions. Overall, this paper will highlight on the existing technologies and emerging trends in designing of finned-tube heat exchangers considering different arrangements and geometric parameters under variable flow conditions which will be helpful for selecting appropriate design depending on the requirement. [ABSTRACT FROM AUTHOR]

The presence of superheated vapor in condenser heat exchanger is common in many applications, as heat pump or organic Rankine cycle. Rarely taken into consideration in the literature of plate heat exchangers, the present article focuses on the influence of the superheated vapor on the condensation characteristics of an organic fluid (pentane) in a brazed plate heat exchanger (BPHE). A specific experimental approach has been developed for this objective. The tested BPHE prototype consists of 2 channels with chevron angle of 55°, and a hydraulic diameter equal to 4.4 mm. The effect of the pentane mass flux, 9–30 kg m −2 s −1 , and the vapor superheat, 5–25 K, at a mean constant saturation temperature of 36.5 °C (1.029 bars), on the global and local thermo-hydraulic characteristics has been identified. An infrared (IR) metrology is used to distinguish the different fluid state distributions, which are representative of various heat transfers along the BPHE. The IR thermography shows a significant impact of the vapor superheat, on the fluid distribution at the channel inlet depending on the mass flux. Comparing the results with vapor superheat going from 5 to 25 K, we note: 1/an increase of the heat transfer coefficient reaching 70% for the lowest mass flux; 2/an increase of the pressure drop, whose rate (18%) is equivalent to the increase of the heat transfer coefficient for the larger mass fluxes. Superheated vapor is therefore very favorable to heat transfer for condensation in the gravity mode compared to the convective one. Based on experimental measurements and observations, various vapor desuperheating scenarios are tested. The analysis justifies that the suitable desuperheating scenario involves condensation from superheated vapor directly from the channel inlet with liquid vaporization from the condensate film. [ABSTRACT FROM AUTHOR]

To research the characteristics of the transient variation of pressure in a nuclear power station condenser under accident condition, a mathematical model was established which simulated the cycling cooling water, heat transfer and pressure in the condenser. The calculation program of transient variation characteristics was established in Fortran language. The pump's parameter, cooling line's organization, check valve's feature and the parameter of siphonic water-collecting well are involved in the cooling water flow's mathematical model. The initial conditions of control volume are determined by the steady state of the condenser. The transient characteristics of a 1000 MW nuclear power station's condenser and cooling water system were examined. The results show that at the condition of plant-powersuspension of pump, the cooling water flow rate decreases rapidly and refluxes, then fluctuates to 0. The variation of heat transfer coefficient in the condenser has three stages: at start it decreases sharply, then increases and decreases, and keeps constant in the end. Under three conditions (design, water and summer), the condenser pressure goes up in fluctuation. The time intervals between condenser's pressure signals under three conditions are about 26.4 s, which can fulfill the requirement for safe operation of nuclear power station. [ABSTRACT FROM AUTHOR]

This paper presents a computer code based on a simplified model for sizing a horizontal shell and tube refrigerant condenser. The model uses three-zone approach for condensing-side and overall approach for the coolant-side of the condenser. Given the thermal and hydraulic data, the code reads many different exchanger configurations from the tube count table and calculates the pressure drop, required heat transfer area and exchanger length for each configuration and then selects the one that has the smallest exchanger area for lowering the initial cost. The model has been experimentally validated by testing a shell-and-tube refrigerant condenser that water flows on tube-side as coolant while R-134a as refrigerant condenses on shell-side. The experimental system is a vapour compression chiller unit using R-134a as refrigerant. The measured and predicted values of the length and the heat transfer area of the tested condenser are in good agreement. The maximum absolute differences between the output of the code and the measured values of the heat rate and heat transfer area are 13% and 7%, respectively. [ABSTRACT FROM AUTHOR]

Abstract: The accurate prediction of the horizontal in-tube condensation heat transfer is a primary concern in the optimum design and safety analysis of horizontal heat exchangers of passive safety systems such as the passive containment cooling system (PCCS), the emergency condenser system (ECS) and the passive auxiliary feed-water system (PAFS). It is essential to analyze and assess the predictive capability of the previous horizontal in-tube condensation models for each flow regime using various experimental data. This study assessed totally 11 condensation models for the stratified flow, one of the main flow regime encountered in the horizontal condenser, with the heat transfer data from the Purdue-PCCS experiment using the multi-dimensional analysis of reactor safety (MARS) code. From the assessments, it was found that the models by Akers and Rosson, Chato, Tandon et al., Sweeney and Chato, and Cavallini et al. (2002) under-predicted the data in the main condensation heat transfer region, on the contrary to this, the models by Rosson and Meyers, Jaster and Kosky, Fujii, Dobson and Chato, and Thome et al. similarly- or over-predicted the data, and especially, Cavallini et al. (2006) model shows good predictive capability for all test conditions. The results of this study can be used importantly to improve the condensation models in thermal hydraulic code, such as RELAP5 or MARS code. [Copyright &y& Elsevier]