Experimental Analysis of the Vapour Compression Refrigeration System with Microchannel Condenser using R134a and R1234yf Refrigerant

Vapour Compression Refrigeration (VCR) system with high COP, low input power consumption and minimal exergy losses are of great research hotspot. The current research focuses on analysis of exergy and performance of vapour compression refrigeration (VCR) cycle is in a real-world application. Experiments were carried out in the VCR system using round tube condenser and microchannel condenser along with different refrigerants R134a, and R1234yf. Temperatures were varied from +20°C to 5°C for the evaporator and 40°C to 50°C for the condenser. Among the two refrigerants, experimental results show that refrigerants operating in micro-channel condensers have COP of 6% and 4%greater higher with5% and 3% lower exergy loss compared to the round tube condenser for R134a and R1234yf respectively.R1234yf appears to be a better equivalent for R134a, according to the findings. The efficiency defect in the condenser is the greatest and least in the evaporator for the coolants examined.

Theoretical estimation of efficiency defect in Vapour Compression Refrigeration system using R1234yf, R134a and R1234ze

In presented work, researchers have used efficiency defect as a tool for checking the utility of different refrigerants in Vapour compression refrigeration system. A mathematical model of simple Vapour compression refrigeration system is created. Using first law analysis and exergy analysis efficiency defect is calculated for various components of the system individually and whole vapour compression refrigeration system as well. It is found that R1234yf has highest value of efficiency defect for whole system, whereas R134a has least value of efficiency defect for whole system. Variation of efficiency defect of various components with evaporator temperature is also presented as graphs.

Performance investigation and exergy analysis of vapor compression refrigeration system operated using R600a refrigerant and nanoadditive compressor oil

Compression of vaporized refrigerant is the essential process of the refrigeration cycle which is performed by using a compressor. The amount of power consumed by a refrigeration system is governed by the work input given to its compressor, which also determines the COP of the system. By reducing the work input given to the compressor, the power consumption of refrigerator is reduced along with the improvement in its COP. Nowadays, nanoparticles have emerged as the new generation additives in various working fluids because of their remarkable ability to improve the heat transfer, tribological and other thermophysical properties of the base fluid. In such a vein, we propose a compressor oil based nanofluid prepared by dispersing nanoparticles into the conventional compressor oil. In the present study, four samples of nanoadditive compressor oil were prepared by dispersing the nanoparticles like Al2O3, TiO2, and ZnO into the conventional mineral oil as a lubricant. The tribological properties of this four samples were studied, out of which one sample gave a better lubrication and heat transfer properties which are considered as one of the key parameters for reducing work input to the compressor, this can result in reduced power consumption, with enhancement of COP. These results are analyzed experimentally by carrying out performance and exergy analysis in a vapor compression refrigeration system, using R600a as a refrigerant. The experimental results show that, there is an improvement of COP by 14.61% and exergy efficiency by 7.51%. Also, the efficiency defect in the major components of vapor compression refrigeration system has been reduced effectively.

Thermodynamic investigations of Zeotropic mixture of R290, R23 and R14 on three-stage auto refrigerating cascade system

The zeotropic mixture of environment friendly refrigerants (hydrocarbons and hydrofluorocarbons) being the only alternatives for working fluid in low temperature refrigeration system. Hence, three-stage auto refrigerating cascade system was studied for the existence using four combinations of three-component zeotropic mixture of six different refrigerants. The exergy analysis confirmed the existence of three-stage auto refrigerating cascade system. The performances of the system like coefficient of performance, exergy lost, exergic efficiency, efficiency defect, and the evaporating temperature achieved were investigated for different mass fractions in order to verify the effect of mass fraction on them. In accordance with the environmental issues and the process of sustainable development, the three-component zeotropic mixture of R290/R23/R14 with the mass fraction of 0.218:0.346:0.436 was performing better and hence can be suggested as an alternative refrigerant for three-stage auto refrigerating cascade system operating at very low evaporating temperature in the range of ?97?C (176 K), at coefficient of performance of 0.253 and comparatively increased exergic efficiency up to 16.3% (58.5%).

The Quest for More Efficient Industrial Engines: A Review of Current Industrial Engine Development and Applications

This paper addresses the need for efficiency gains in the modern industrial engine as utilized in combined heat and power (CHP) generation and other distributed generation situations. Power generation is discussed in terms of reciprocating-engine-based plant operating on Otto type thermodynamic cycles. The current state of the technology and the research being conducted is examined. Internal combustion engine performance improvement in the industrial engine sector focuses on improvements in the combustion characteristics of the plant, with emphasis on areas such as piston design, valve timing, and supercharging. Maximum brake-thermal efficiencies, in percentage terms, are currently in the 40s. In CHP generation, most of the energy not utilized for mechanical power is recovered as heat from various engine systems, such as jacket water and exhaust, and utilized for space or process heating. In other distributed generation situations, this energy is not utilized in this manner and is lost to the surroundings. While second law analysis would provide a more meaningful interpretation of the efficiency defect, this approach is still not the norm. Distributed generation benefits directly from efficiency improvements; the more efficient use of primary energy leads to reduced fuel costs. Combined heat and power generation is, however, more sensitive to the matching between the plant and its energy sinks, as its successful implementation is dictated by the ability of a site to fully utilize the heat and electrical power produced by the plant. At present, the energy balance of such engines typically dictates that heat is produced in greater quantity than electrical power, the ratio being of the order of 1.1–1.5:1. Due to this production imbalance, it is accepted that in order to be economically feasible, thermal and electrical demand should be coincident and also all heat and power should be utilized. This has traditionally led to certain sectors being deemed unsuitable for CHP use. Some current research is aimed at tipping the production balance of these engines in favor of electrical power production; however, performance gains in this regard are slow. This paper concludes with some brief commentary on current industrial engine developments and applications.

The Quest for More Efficient Industrial Engines: A Review of Current Industrial Engine Development and Applications

The paper addresses the need for efficiency gains in the modern industrial engine as utilized in Combined Heat and Power (CHP) generation and other Distributed Generation (DG) situations. Power generation is discussed in terms of reciprocating-engine-based plant operating on Otto type thermodynamic cycles. The current state of the technology and the research being conducted is examined. Internal combustion engine (ICE) performance improvement in the industrial engine sector focuses on improvements in the combustion characteristics of the plant, with emphasis on areas such as piston design, valve timing and supercharging. Maximum brake thermal efficiencies, in percentage terms, are currently in the forties. In CHP generation, most of the energy not utilised for mechanical power is recovered as heat from various engine systems such as jacket water and exhaust and utilised for space or process heating. In other Distributed Generation situations, this energy is not utilised in this manner and is lost to the surroundings. While second law analysis would provide a more meaningful interpretation of the efficiency defect, this approach is still not the norm. Distributed Generation benefits directly from efficiency improvements; the more efficient use of primary energy leads to reduced fuel costs. Combined Heat and Power generation is, however, more sensitive to the matching between the plant and its energy sinks, as its successful implementation is dictated by the ability of a site to fully utilise the heat and electrical power produced by the plant. At present, the energy balance of such engines typically dictates that heat is produced in greater quantity than electrical power, the ratio being of the order of 1.1 — 1.5: 1. Due to this production imbalance, it is accepted that in order to be economically feasible, thermal and electrical demand should be coincident and also all heat and power should be utilised. This has traditionally led to certain sectors being deemed unsuitable for CHP use. Some current research is aimed at tipping the production balance of these engines in favour of electrical power production; however, performance gains in this regard are slow. The paper concludes with some brief commentary on current industrial engine developments and applications and proposes some directions for progress.