M. Prakash Maiya

Bio: M. Prakash Maiya is an academic researcher from Indian Institutes of Technology. The author has contributed to research in topic(s): Compressed hydrogen & High-pressure electrolysis. The author has an hindex of 2, co-authored 2 publication(s) receiving 22 citation(s).

Investigations on triple fluid vapour absorption refrigerator

Abstract: This Paper deals with theoretical and experimental investigations on the triple fluid vapour absorption refrigerator (TFVAR) in relation to the gas circuit, thermo-siphon and inert gas charge pressure. The charges of the various fluids were estimated. Helium seems to be a better inert gas than hydrogen. A compact absorber design is proposed.

Performance of air cooled hydrogen storage device with external fins

Abstract: Minimization of total weight is the major criterion in the design of a solid state hydrogen storage device for mobile or portable applications. The design should also address the requirements such as storage capacity, charge/discharge rates, space constraints, coolant temperature and hydrogen supply pressure. To achieve this, one should be able to reliably predict the dynamic performance of the storage device. In this paper, a parametric study of hydrogen sorption in an air-cooled annular cylindrical hydrogen storage device with external fins is reported. LaNi 5 , which has excellent hydrogen storage properties is used as the hydriding material. The influence of different geometric parameters such as hydride bed thickness and fin height, and operational parameters such as hydrogen supply pressure and cooling air temperature are studied. Copyright , Manchester University Press.

A review of absorption refrigeration technologies

Abstract: This paper provides a literature review on absorption refrigeration technology. A number of research options such as various types of absorption refrigeration systems, research on working fluids, and improvement of absorption processes are discussed.

Domestic refrigerators : recent developments

Abstract: The refrigerator/freezer is one of the most important and the biggest energy-consuming home appliances. There are several literature references that discuss the historical development of refrigeration 1–14 . Most of them, however, consider historical highlights up to several decades ago. This paper summarizes recent developments in the field of domestic household refrigerators based on a survey of publications and patents.

Simulation and experimental investigation into diffusion absorption cooling machines for air-conditioning applications

Abstract: The paper presents the development, experimental analysis and simulation of a solar heat driven ammonia/water (NH3/H2O) diffusion–absorption cooling machine (DACM). The designed cooling capacity of the machine is 2.5 kW for air-conditioning applications. The indirectly heated generator with its bubble pump is the main new feature of this cooling machine and it showed good performance for all prototypes constructed. A major challenge of the technology is the constant total pressure level in all components, which makes condensate distribution into the evaporator vertical tubes with no distribution pressure extremely difficult. As a consequence, the first prototype had problems in the auxiliary gas circuit, which only works with very low driving pressures and stops to work, when evaporation rates decay. In the second prototype, the auxiliary gas circulation was improved. However, the liquid condensate distribution into the evaporator remained problematically and the cooling power was limited to 1.6 kW maximum. Coaxial solution heat exchangers gave much better performance results than the initially chosen plate heat exchangers. In the third prototype the evaporator was optimised and the cooling capacity could be increased to 3 kW maximum. The maximum COP reached was 0.38. The diffusion–absorption cycle was modelled using an expanded characteristic equation of sorption chillers. The simulation model showed good agreement with the measured data.

Review of diffusion–absorption refrigeration technologies

Abstract: A review of diffusion–absorption refrigeration technologies has been done in this work in order to promote their main characteristics in terms of the refrigeration process, their applications, work fluids, current trends and limitations, among others. Over 70 publications in the field were analyzed concluding that diffusion–absorption technology represents a complementary and viable alternative in the field of refrigeration technologies for small cooling capacity, due to an increase in the current demand of refrigeration and air-conditioning devices.

Studies on bubble pump for a water-lithium bromide vapour absorption refrigerator

Abstract: The hydrostatic principle and bubble pump technique are used in the two-fluid pumpless continuous vapour absorption refrigerator to create the circulations of the solution and refrigerant. In this paper, the bubble pump, which is the `heart' of this natural circulation type of refrigerator, has been investigated both analytically and experimentally. The bubble pump is modelled for intermittent slug flow of solution and vapour mixture. A test rig is built in glass to evaluate the performance of the bubble pump, to visualize the flow behavior and to validate the analytical model. Bubble pump tube diameter, pump lift, driving head and heat input are varied to analyze the pump performance. Results indicate that pumping ratio is nearly independent of the heat input, but increases with decrease in pump tube diameter, decrease in pump lift and increase in driving head.