N. Beemkumar

Performance improvement of D-sorbitol PCM-based energy storage system with different fins

ABSTRACT This paper is aimed at enhancing the heat exchange rate in the thermal energy storage system with dissimilar fins and encapsulation materials. Experimentation is done with d-sorbitol as phase change material with different encapsulating materials, copper, stainless steel (SS) and brass, in pin fin, annular fin and rectangular fin. The results are analysed for their thermal performance characteristics during both the charging and discharging processes. During charging, copper encapsulation showed a higher heat energy transfer rate around 2340u2005kJ. During discharging, a loss of 22% in heat extraction is seen in copper encapsulations, 6% and 19% in brass and SS encapsulations, respectively. These results show that the usage of annular fins is a valuable practice to increase the heat stored and recovered, in a latent heat storage system. The most cost-effective encapsulation is SS balls with annular fins as compared with copper and brass encapsulations.

Heat transfer enhancement of the latent heat storage system using different encapsulating materials with and without fins

This study is aimed at analysing the heat transfer characteristics of different encapsulating materials and the fins on the overall heat transfer in the latent heat storage system (LHSS). Experimentation is done with different phase change materials (PCMs) (d-mannitol, d-sorbitol and paraffin wax) using different encapsulating materials, i.e. copper, aluminium and brass, with and without fins. During the charging process, there is an average 15% heat loss of copper encapsulations without using fins as compared with using fins. The heat losses in aluminium and brass encapsulations are 10% and 15%, respectively. In the discharging process, 23% of heat extraction loss is seen in copper encapsulations, 5% and 18% in aluminium and brass encapsulations, respectively. The results showed that the usage of fins is an effective technique to increase the heat stored and recovered in a LHSS. The most cost-effective encapsulation is aluminium balls with fins as it has the lowest cost/kJ as compared with other two.

Experimental investigation on air cooler with thermal storage

The domestic air coolers, which are cost effective, play a positive role in providing human comfort during hot weather [5]. However the performance is dissatisfactory in the high humid regions. This project paves a way to investigate the performance of air cooler integrated with phase change material (PCM) by eliminating the problem of rise in humidity that usually encountered in the conventional air cooler. The objective of the present invention is to provide cooled air to maintain the room temperature according to the requirement. This type of air cooler consists of heat exchanger, air duct and variable speed fan. Before the use of the mobile air cooler, the PCM filled heat exchanger tubes are kept in a domestic refrigerator for few hours depending on the requirement. During this period the phase change material in the tubes are get converted to solid and stores cold energy as latent heat of fusion. This is known as cold energy charging process. The charged PCM filled heat exchanger tubes are to be fitted to the heat exchanger whenever the customer needs to use this “Air Cooler with Thermal Storage”. When “Air Cooler with Thermal Storage” is switched on, the atmospheric air gets circulated by the fan passes through the heat exchanger and finally air gets cooled by the Ice/phase change material. During that time, The Ice/phase change material absorbs the heat present in the air and changes its phase from solid to liquid. This process is known as cold energy discharging process. This cooled air is focused to the area where occupants are present and cooling can be achieved locally.

Enhancing heat transfer rate in a car radiator by using Al2O3 nanofluid as a coolant

ABSTRACT Conventional fluids such as water, ethylene glycol and mineral oils are normally used as heat transfer fluids. Various techniques are applied to enhance the heat transfer. Heat exchange of the coolant moving through the vehicle radiators is of incredible significance for the advancement of fuel utilisation. In this experiment, the heat transfer performance of the automobile radiator is evaluated experimentally. For this we have taken two different combinations of nanoparticles. Aluminium oxide (Al2O3) and magnesium oxide (MgO) nanoparticles are added to the base fluid (80% wateru2009+u200920% ethylene glycol) at two concentrations 0.12% and 0.4% volume concentration considering the best pH for longer stability. Similarly, another combination with aluminium oxide (Al2O3) and titanium oxide (TiO2) at the same volume concentrations of 0.12% and 0.4% in the base fluid is also prepared. Furthermore, this increases nanoparticle concentration, air velocity and nanofluid velocity and enhances the overall heat transfer coefficient.

Performance study of a domestic refrigerator using CuO/AL2O3-R22 nanorefrigerant as a working fluid

ABSTRACT This work is a performance study that investigated the nanorefrigerant CuO/AL2O3-R22 used in a refrigerator without any remodelling of the system. The refrigerator performance was then investigated using energy consumption test and enhancing heat transfer rate. The heat transfer enhancement was investigated on the surface of a refrigerator by using the nanorefrigerant Al2O3/CuO. The results indicate that CuO-R22 works normally and safely in a refrigerator and has better power consumption and heat transfer rate. Thus, using CuO-R22 as nanorefrigerant in domestic refrigerators is feasible for better heat transfer rate.

Analysis of heat transfer through a high strength concrete with circular pipe in a safety vessel of reactor vault

ABSTRACT Reactor Vault (RV) is an important structure that supports the main vessel and safety vessel of a reactor. It is a heavy cylindrical structure built around the safety vessel. The RV is divided into an inner and outer wall. The inner wall is of 600u2009mm thickness and is made of borated concrete, while the outer wall is made up of structural concrete. The outer wall is the main load-bearing member, whereas the inner wall supports only the safety vessel. To prepare a cylindrical model of RV using high strength concrete with special additive and to perform heat transfer analysis on the block to study the effect of air cavities present in the RV model on contact conductance, thermal conductivity and its heat transfer characteristics are studied experimentally.

Effect of diethyl ether blended with neem oil methyl esters in CI engine

ABSTRACT Vegetable oils are now considered to be a potential alternative that can be used in place of partial or total substitution of diesel fuels. In this study, we used diethyl ether as an oxygenated additive to investigate the possible use of higher percentages of biodiesel in an unmodified diesel engine. Neem oil was selected for biodiesel production. The tests were performed at a steady-state condition in a single-cylinder constant speed DI diesel engine. The combustion process involved in diesel engine would be improved and the particulate matter would be reduced if these biodiesels are blended. An experimental investigation is carried out to establish the emission characteristics of a direct injection diesel engine using diethyl ether as additive in Neat Neem oil Biodiesel. Emissions of hydro carbon oxides of nitrogen and carbon monoxide significantly reduced by adding diethyl ether into neem oil biodiesel at 10% and 20% on volume basis.

Experimental analysis of mechanical properties of aluminium alloy weldments by friction welding process under cryogenic treatment

ABSTRACT The present study explores the mechanical and metallurgical properties of friction-welded dissimilar aluminium joints, namely AA6061-T6 and AA7079-T6 which were investigated with the use of a process parameter such as frictional pressure, upset pressure, speed, burn-off length. The parameters are varied according to L9 orthogonal array with three levels. The samples are subjected to non-destructive test to identify the weld integrity without disturbing the component which ensures the weld metals for fitness-for-purpose. Mechanical and metallurgical properties such as tensile strength, hardness and micro structure with 100× and 500× were taken to validate the process. Shallow cryogenic treatment was conducted with different time periods (48 and 72u2009h). There was no significant improvement rather than reduction in tensile strength for 48u2009h, but for 72u2009h, there was an increase in maximum tensile strength of 224u2009MPa. The welded zone showed complete fusions with some inter metallic phases that are obtained.

Thermal Analysis of Fluidized Bed and Fixed Bed Latent Heat Thermal Storage System

Thermal energy storage technology is essential because its stores available energy at low cost. Objective of the work is to store the thermal energy in a most efficient method. This work is deal with thermal analysis of fluidized bed and fixed bed latent heat thermal storage (LHTS) system with different encapsulation materials (aluminium, brass and copper). D-Mannitol has been used as phase change material (PCM). Encapsulation material which is in orbicular shape with 4 inch diameter and 2 mm thickness orbicular shaped product is used. Therminol-66 is used as a heat transfer fluid (HTF). Arrangement of encapsulation material is done in two ways namely fluidized bed and fixed bed thermal storage system. Comparison was made between the performance of fixed bed and fluidized bed with different encapsulation material. It is observed that from the economical point of view aluminium in fluidized bed LHTS System has highest efficiency than copper and brass. The thermal energy storage system can be analyzed with fixed bed by varying mass flow rate of oil paves a way to find effective heat energy transfer.

Investigation of Sensible and Latent Heat Storage System using various HTF

The objective of the work is investigating the latent heat storage system by varying heat transfer fluid (HTF). In this experiment, the effect of using different heat transfer fluids on the combined system is studied while using a low melting phase change material (PCM) i.e., paraffin wax. The heat transfer fluids chosen are water (low boiling fluid) and Therminol-66 (High boiling fluid). A comparison is made between the heat transfers by employing both the Heat transfer fluids. In the beginning, water is made to flow as the HTF and the charging process is undertaken followed by the discharging process by utilizing the different encapsulation materials namely, copper, aluminium and brass. These processes are then repeated for therminol-66 as HTF. At the end of the experiment it was concluded that even though therminol-66 enhances the latent heat storage capacity, water offers a higher sensible heat storage capacity, making it a better HTF for low melting PCM. Similar to above said process the experiments can be conducted for high and medium range melting point PCM with variation of HTF.