A Study on a Numerical Modelling of Discharge Line Flow Analysis of a Household Type Refrigerator

The main component that determines the performance and efficiency of the refrigeration system is the compressor, which is the major energy consumer in a vapor-compression refrigeration system. In hermetic compressors for household refrigerators, one of the major factors that influences the total compressor efficiency is the flow efficiency of discharge line. In order to find out the effect of the structural changes to flow losses and pressure fluctuations at discharge line, this paper presents a three-dimensional CFD model and experimental study of a hermetic reciprocating compressor. In the first phase of this study, transient numerical flow analysis was developed and it was determined whether or not it overlaps with the experimental measurements. The CFD model results were compared with the experimentally obtained pV indicator diagram and transient pressure measurements of discharge plenum by varying the rotation speed of the modelled inverter hermetic reciprocating compressor. The result of the studies helps to identify the effect of the discharge line design parameters to the system performance

Investigation of Flow Losses Through Discharge Line of Household Type Refrigerator Compressors

Nowadays, increasing the efficiency of white goods and small house appliances has become necessity as a result of the technological developments, competition and energy policies. As a basic component of the cooling system, compressor is the most fundamental element for determining the performance and efficiency of the system. In hermetic compressors for household refrigerators, one of the major factors of total compressor efficiency is the discharge line flow efficiency. In this paper, the effects of some of the structural changes to flow losses at discharge line of a hermetic reciprocating compressor were investigated experimentally. For this study, 3 different conceptual designs were created based on the discharge line design parameters such as line diameter, resonator volumes and line length. By performing precise pressure measurements and calorimeter tests, performance and pressure drop rates of conceptual designs were compared against the base model and each other of the conceptual design compressors. The result of the experimental studies helps to identify the effect of the discharge line design parameters to the system performance

Transient exergy analysis of the condenser and evaporator of an air source heat pump water heater

In this study the performance of an air source heat pump water heater is assessed from exergy point of view in component wise. In order to investigate the work potential of energy, the destruction on the exergy is analyzed and results are summarized for the components individually. The exergy destruction of the system is studied by considering real paths of the pressure and temperature data which are collected during the experiments of the ASHPWH under varying environmental conditions. In the following step, the evolution of the exergy destruction of the system is calculated by a code which is compiled on MATLAB along these temperature and pressure paths. The obtained results reveal the importance of the transient exergy analysis by providing detailed information about exergy destruction of the system such as where it drives up and reaches up to its max and where it drops down and evolves on a smooth path.Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016

Analysis of an irreversible Ericsson engine with a realistic regenerator

An internally irreversible Ericsson engine, with a realistic regenerator, has been analyzed. The study considers internal irreversibilities with the introduction of turbine and compressor thermal-efficiencies and pressure-drops present in realistic regenerators. The effects of internal irreversibilities on the power output and thermal efficiency of the cycle have been determined using the finite-time thermodynamics. Maximum power-density, rather than maximum power, was used as the criterion for optimization, with the objective of having a more efficient small-sized engine.

Optimal design of the regenerative gas turbine engine with isothermal heat addition

A regenerative gas turbine engine, with isothermal heat addition, working under the frame of a Brayton cycle has been analyzed. With the purpose of having a more efficient small-sized gas turbine engine, the optimization has been carried out numerically using the maximum power (MP) and maximum power density (MPD) method. The effects of internal irreversibilities have been considered in terms of the isentropic efficiencies of the turbine and compressor and of the regenerator efficiency. The results summarized by figures show that the regenerative gas turbine engine, with isothermal heat addition, designed according to the maximum power density condition gives the best performance and exhibits highest cycle efficiencies.

A road map for the realization of global-scale thorium breeding fuel cycle by single molten-fluoride flow. Energy Conversion and Management 49

Abstract For global survival, we need to launch a rapid regeneration of the nuclear power industry. The replacement of the present fossil fuel industry requires a doubling time for alternative energy sources of 5-7 years and only nuclear energy has the capability to achieve this. The liquid metal cooled fast breeder reactors (LMFBR) have the best breeding criteria but the doubling time exceeds 20 years. Further, the use of plutonium in these systems has the potential of nuclear proliferation. The Thorium Molten-Salt Nuclear Energy Synergetic System [THORIMS-NES], described here is a symbiotic system, based on the thorium-uranium-233 cycle. The production of trans-uranium elements is essentially absent in Th-U system, which simplifies the issue of nuclear waste management. The use of 233 U contaminated with 232 U as fissile material, instead of plutonium/ 235 U makes this system nuclear proliferation resistant. The energy is produced in molten-salt reactors (FUJI) and fissile 233 U is produced by spallation in Accelerator Molten-Salt Breeders (AMSB). This system uses the multi-functional ''single-phase molten-fluoride" circulation system for all operations. There are no difficulties relating to ''radiation-damage", ''heat-removal" and ''chemical processing" owing to the simple ''idealistic ionic liquid" character of the fuel. FUJI is size-flexible, and can use all kinds of fissile material achieving a nearly fuel self-sustaining condition without continuous chemical processing of fuel salt and without core-graphite replacement for the life of the reactor. The AMSB is based on a single-fluid molten-salt target/blanket concept. Several AMSBs can be accommodated in regional centers for the production of fissile 233 U, with batch chemical processing including radio-waste management. FUJI reactor and the AMSB can also be used for the transmutation of long-lived radioactive elements in the wastes and has a high potential for producing hydrogen-fuel in molten-salt reactors. The development and launching of THORIMS-NES requires the following three programs during the next three decades: 0196-8904/$ -see front matter