In this article, the behavior of heat and mass transfer relation during khoa making has been investigated. Various indoor experiments have been performed for simulation of developed thermal model for maximum evaporation during heating of milk. The data obtained from experimentation have been used to determine values of constant “C” and exponent “n” by simple regression analysis. Based on the values of “C” and “n,” convective and evaporative heat transfer coefficients for milk were determined. It was observed that the convective and evaporative heat transfer coefficients decrease with the increase in rate of heating (varying voltage). It was also observed that convective and evaporative heat transfer coefficients increase with the increase in operating temperature. The rate of increment of evaporative heat transfer coefficient is higher than the convective heat transfer coefficient. The experimental error in terms of percent uncertainty was also calculated. PRACTICAL APPLICATIONS The traditional method of khoa making (i.e., open pan evaporation process) requires a large quantity of energy and in the present era, energy saving is needed to pay sufficient attention. In rural India, generally, wood, cattle dung, coal, kerosene, etc. are used in open chulah as fuel for khoa making which is hardly 8–10% thermally efficient. A number of research articles are available in the literature explaining the mechanization of khoa making process. But even today, the khoa making technology in rural India much remains the same. Thus, by keeping energy saving aspect in mind, the traditional method of khoa making has been further explored.

Today, most of the electricity produced throughout the world is from steam power plants. However, electricity is being produced by some other power generation sources such as hydropower, gas power, bio-gas power, solar cells, etc. One newly devel-oped method of electricity generation is the Magneto hydro dynamic power plant. This paper deals with steam cycles used in power plants. Thermodynamic analysis of the Rankine cycle has been undertaken to enhance the efficiency and reli-ability of steam power plants. The thermodynamic deviations resulting in non-ideal or irreversible func-tioning of various steam power plant components have been identified. A comparative study between the Carnot cycle and Rankine cycle efficiency has been analyzed resulting in the introduction of regen-eration in the Rankine cycle. Factors affecting effi-ciency of the Rankine cycle have been identified and analyzed for improved working of thermal power plants.

Longitudinal vortices have a great capability of disrupting the growth of boundary layers and bring about the heat transfer enhancement between the fluid and its neighbouring surface. The potential of a winglet pair type vortex generator for the heat transfer enhancement in a plate fin heat exchanger, with triangular fins as inserts, is numerically evaluated in this article. The rectangular winglet pair is mounted on the triangular fins. The numerical computations are performed by solving an unsteady, three-dimensional Navier-Stokes equation, and an energy equation by using the modified MAC method. Air is taken as the working fluid. This study shows the flow structure and the performance of the winglet pair in improving the heat transfer. The computations are performed at Re = 200 and placing the winglet at an angle of attack, β = 20 • . The results show that the heat transfer is increased by 13 per cent, even at the exit, with the winglet pair. The heat transfer enhancement with a winglet pair for different Re = 200-500 and Pr = 0.71 and for varying heights of the winglet pair is also predicted.

An air-conditioning system utilizing solar energy would generally be more efficient, cost wise, if it was used to provide both heating and cooling requirements in the building it serves. Various solar powered heating systems have been tested extensively, but solar powered air conditioning systems have received very little attention. Solar powered absorption cooling systems can serve both heating and cooling requirements in the building it serves. Many researchers have studied the solar absorption air conditioning system in order to make it economically and technically viable. But still, much more research in this area is needed. This paper will help many researchers working in this area and provide them with fundamental knowledge on absorption systems, and a detailed review on the past efforts in the field of solar absorption cooling systems with the absorption pair of lithium-bromide and water. This knowledge will help them to start the parametric study in order to investigate the influence of key parameters on the overall system performance.

ABSTRACT

This research paper reports the results for convective heat transfer coefficient and nucleate boiling heat flux for pool boiling of milk during khoa making. Various indoor experiments were conducted for different heat flux inputs varying from 9638.55 to 14457.83 W/m 2 . Experimental data obtained for pool boiling of milk were analyzed by using the Rohsenow correlation with the help of simple linear regression analysis. The convective heat transfer coefficients were estimated in the range of 334.48 to 837.78 W/m 2 °C for the given heat inputs. The results for heat flux were found to be varying from 3344.8 to 8377.8 W/m 2 at 10 °C excess temperature of the aluminum pot surface above the saturation temperature of the milk. The experimental errors in terms of percent uncertainty were also calculated.

This paper presents modelling and simulation of a solar absorption cooling system. In this paper, the modelling of a solar-powered, single stage, absorption cooling system, using a flat plate collector and water-lithium bromide solution, is done. A computer program has been developed for the absorption system to simulate various cycle configurations with the help of various weather data for the village Bahal, District Bhiwani, Haryana, India. The effects of hot water inlet temperatures on the coefficient of performance (COP) and the surface area of the absorption cooling component are studied. The hot water inlet temperature is found to affect the surface area of some of the system components. Moreover the effect of the reference temperature which is the minimum allowable hot water inlet temperature on the fraction of total load met by non-purchased energy (FNP) and coefficient of performance (COP) is studied and it is found that high reference temperature increases the system COP and decreases the surface area of system components but lower reference temperature gives better results for FNP than high reference temperatures.

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