Refrigeration Air Conditioning Research Articles

High-Pressure Refrigerant Gas Injection Injury to the Hand

High-pressure injection injuries, although rare, are commonly discussed orthopaedic surgical emergencies. In many cases, high-pressure injection injuries can have detrimental effects on the patient. However, there are rare instances where surgical intervention may be more harmful than helpful. Here, we present a case report of a patient who sustained a high-pressure chemical refrigerant injection injury into the palm of his hand working on an air conditioning refrigeration unit. He was treated nonsurgically with excellent outcomes. The aim of this case report was to bring awareness to the potential nonsurgical management of high-pressure injection injuries in select circumstances.

Simulation analysis and optimization of thermoelectric refrigeration and air conditioning

Abstract Thermoelectric refrigeration technology is mainly through the Peltier effect to achieve refrigeration, thermoelectric refrigeration air conditioning needs to be combined with a certain air flow rate to realize the separation of cold and heat, and make full use of the cold end to realize the refrigeration function, or else the refrigeration efficiency is seriously affected. Based on the ICEPAK simulation platform of ANSYS, we analyze the influence of structure and parameter settings on the conversion efficiency of thermoelectric refrigeration air conditioning fan under the established boundary conditions, establish the relationship between air flow rate and temperature drop value, and put forward the optimization of the product structure design scheme, and the results of the optimization scheme show that there is a peak in the operating current at a certain heat dissipation efficiency; and lengthening the length of the air ducts through the optimization of the structure can enhance the refrigeration effect of the air conditioner.

Impact of concrete durability improvement on building life cycle carbon emissions: a case study of residential buildings in Northwest China.

Building carbon emissions (CE) have become the focus of the current topic, but there is still no mature typical building life cycle theory method from the perspective of building materials, and the research on the relationship between building durability and building life cycle is still insufficient. To this end, this study established a detailed calculation method for building carbon emissions (CE) and divided the building life cycle (BLC) into three stages: manufacturing, use, and demolition according to the result analysis. In addition, a durability improvement and carbon reduction scheme of "partition, resistance, and repair" is proposed, and the carbon emission reduction index of effectiveness index is proposed. The proposed method is applied to the case of residential buildings in Northwest China. The main conclusions are as follows: the CE of residential buildings are more dependent on the use stage. If the centralized heating system is adopted, the CE in the operation stage account for 80-90%. If the air conditioning refrigeration and heating system is adopted, the CE in the operation stage account for about 50%. Using the method of improving the durability of buildings to extend the service life of buildings is very significant for building carbon reduction (RC); the effectiveness index proposed in this paper includes key indicators such as total CE, service life, and building area. Compared with the traditional index, the effectiveness index is more accurate and comprehensive. CR is the focus of green building, but the impact of economy needs to be considered in practical engineering. In the future research, durability, CE, and economy need to be considered comprehensively for careful study.

Evaluations of energy, exergy, and economic (3E) on a liquefied natural gas (LNG) cold energy utilization system

The LNG cold energy utilization system primarily integrates additional power cycles during the gasification process to harness the cold energy released in this process efficiently. This study introduces a combined cooling and power (CCP) system, which comprises a cascade organic Rankine cycle (ORC), an air conditioning refrigeration (ACR), and a direct expansion cycle (DEC). Furthermore, the thermodynamic and economic analyses of the CCP system were evaluated, and the optimization of each influence parameters was performed by the genetic algorithms, such as the composition of the quaternary mixed working fluid (Methane: Ethane: Propane: i-Butane), condensation pressure, evaporation pressure, and the first-stage expansion pressure within the system. According to the simulation results, the suggested overall exergy destruction of the CCP system proposed by this work is reduced by 13.18% under optimized conditions, with a maximum net power generation of 230.38 kW and an exergy efficiency of 45.58%. Economic analysis reveals that the system's investment cost, annual economic benefits, and levelized energy cost are 2.02 × 106 $, 2.75 × 105 $, and 0.10 $/kWh, respectively. With the system's official operation, the investment cost will be recovered within 8.61 years.

Performance Analysis and Multi-Objective Optimization of a Cooling-Power-Desalination Combined Cycle for Shipboard Diesel Exhaust Heat Recovery

This study presents a novel cooling-power-desalination combined cycle for recovering shipboard diesel exhaust heat, integrating a freezing desalination sub-cycle to regulate the ship’s cooling-load fluctuations. The combined cycle employs ammonia–water as the working fluid and efficiently utilizes excess cooling capacity to pretreat reverse osmosis desalination. By adjusting the mass flow rate of the working fluid in both the air conditioning refrigeration cycle and the freezing desalination sub-cycle, the combined cycle can dynamically meet the cooling-load demand under different working conditions and navigation areas. To analyze the cycle’s performance, a mathematical model is established for energy and exergy analysis, and key parameters including net output work, comprehensive efficiency, and heat exchanger area are optimized using the MOPSO algorithm. The results indicate that the system achieves optimal performance when the generator temperature reaches 249.95 °C, the sea water temperature is 22.29 °C, and 42% ammonia–water is used as the working fluid. Additionally, an economic analysis of frozen seawater desalination as RO seawater desalination pretreatment reveals a substantial cost reduction of 22.69%, showcasing the advantageous features of this proposed cycle. The research in this paper is helpful for waste energy recovery and sustainable development.

Numerical and experimental investigation of laminar and turbulent convective heat transfer in a coiled flow reverser with twisted tape insert

This paper presents a comprehensive investigation of heat transfer enhancement and pressure drop in a Coiled Flow Reverser (CFR) with a twisted tape insert. Both laminar (10 < Re < 2000) and turbulent (12,000 < Re < 18,000) regimes have been studied using both experimental and numerical methods. The effects of twist ratio of twisted tape, inlet Reynolds number, and perforating the twisted tapes have been investigated. The study found that the best performance in the laminar regime is achieved with a twisted tape with a twist ratio of 15.73 and no holes on it at a Reynolds number of 2000. In the turbulent regime, the same twisted tape performs the best at a Reynolds number of 17,000. The highest Thermal Performance Ratio (TPR) in laminar regime is 1.55 and in turbulent regime is 0.99. In comparison to the straight pipe, all types of CFRs show better performance in heat transfer enhancement. Also, as the Reynolds number increases, the friction coefficient decreases in all configurations. The study reveals that the twisted tape insert enhances heat transfer performance while increasing pressure drop. This study provides valuable insights into the design and optimization of heat exchangers with CFR. The findings can be used to improve the efficiency and performance of various industrial processes, such as refrigeration systems, air conditioning, and power plants.

Efisiensi Chiller Gedung Produksi Cat Pt. X

Refrigeration machines and air conditioning machines are an inseparable part of human life in improving the quality of activities. using air conditioning(Air Conditioning). Refrigeration systems in large buildings or those used to cool production machines in the industrial world require energy efficiency. This study uses the CLTD methodCooling Load Temperatur Difference Calculation of heat from each internal and external load of the room refers to the standard ASHRAE Cooling Load Calculation. With the calculation of heat on walls, roofs and floors, it is included in the calculation of external heat loads and the heat of occupants, equipment and lighting is included in internal heat and heat from infiltration and ventilation. Some of the parameter factors considered include heat from building walls, building roofs, building floors, heat in humans working inside, lighting used, production parameters and infiltration factors, ventilation. The value of COcontractualfor chiller 1 it was 6.47 and for chiller 2 it was 8.07. While the value of COPrefrigran is 7.8 for chiller 1 and chiller 2 which is 9.7. The efficiency obtained from these two units is chiller 1 57.4% and chiller 2 58.8%. From the calculation of the cooling load carried out, it is obtained 275576 ??BTU/hr or 330691 BTH/hr after adding 20% ??so that the engine is not burdened, if it is known that 1 kW = 3410 BTU/hr then the cooling load is 97kW.

Probabilistic neural network-based diagnosis of blockage faults in air conditioning and refrigeration units

Abstract The refrigeration unit is a core component of the air conditioner, and its typical faults are pipe scaling and blockage, which can cause refrigerant leakage in serious cases, and these faults can affect the cooling effect of the air conditioner and even affect the safety of using the air conditioner in serious cases. Therefore, it is necessary to study the fault diagnosis system of the refrigeration unit. The traditional fault diagnosis system for refrigeration units, which generally uses wireless sensor networks to transmit data, is a challenge because of its slow diagnosis speed and the low accuracy rate of fault diagnosis for refrigeration units. This paper uses a probabilistic neural network (PNN) to debug a blockage fault diagnosis algorithm system for simulated fault training. The system successfully achieves four levels of pre-warning for blockage faults: “uncertainty, micro-blockage, blockage, and severe blockage”, with the fastest pre-warning time of “uncertainty, micro-blockage” being less than 2 seconds. The experimental results of this paper show that the PNN system can take timely measures against blockage faults, and the fault diagnosis accuracy of the model reaches 97.97%, which is 13.34% higher than the traditional fault identification algorithm. The PNN model can pinpoint the blockage faults of the refrigeration unit, which enables the working state of the refrigeration unit to be continuously optimized, and the air conditioner to maintain energy-efficient operation. The fault simulation of the air conditioning refrigeration unit in automatic control mode verifies the blockage fault diagnosis’s accuracy and the algorithm’s feasibility, providing reference and learning for the development of fault diagnosis algorithms.

Improvement of low-grade heat utilization: Sensitivity mechanism of saturated vapor pressure–temperature in dehumidified materials

Low-grade heat exists widely in industrial processes and nature, but it is difficult to harvest and utilize due to the limitation of existing technology. In this paper, a new concept for improving low-grade heat utilization efficiency is proposed, which relies on absorption refrigeration or solution dehumidification air conditioning system to achieve heat-driven regeneration at a lower temperature by using a multi-component liquid desiccant solution with stronger saturated vapor pressure–temperature sensitivity. It is proved that the regeneration temperature can be reduced by increasing the P-T sensitivity of the dehumidified materials. Further, the paper quantifies the description of the P-T sensitivity and reveals the mechanism of the sensitivity as follows: the higher the charge concentration of ions, the stronger the ion-water molecule dipole interaction, resulting in the lower the concentration of dehumidification solution is required, and thus the stronger the P-T sensitivity. Finally, experimental verification shows that compared with typical LiBr solution as a liquid desiccant, the regeneration temperature of the solution dehumidification system can be reduced by 7.9 ℃ by using a multicomponent solution with higher P-T sensitivity as a liquid desiccant, which also proves that low-grade heat at a lower temperature can be recovered by using the method recommended in this paper.

Parametric study on thermal management system for the range of full (Tesla Model S)/ compact-size (Tesla Model 3) electric vehicles

Electric vehicle is slowly taking over the market share of internal combustion engine vehicle around the globe and range extension study turns into a one key research area. Electric vehicle thermal management system plays a large role in driving range, whereas existing literature mainly focus on component level and lack the vehicle level range analysis. This study conducts a parametric study on the vehicle level thermal management and its impacts on the range of two vehicles (full size - Tesla Model S/ compact size – Tesla Model 3). Vehicle level thermal system model is built considering air conditioning refrigerant loop, indirect battery liquid cooling loop, and cabin cooling air loop. In addition, vehicle propulsion system model is built and utilized in the range simulation. Five feedback controllers are designed for the thermal management system to control the temperature of battery pack, cabin climate, condenser subcool, evaporator superheat, and chiller superheat. Various factors are considered in the parametric study including air conditioning system on/off switch, vehicle size, driving cycle, ambient temperature, cabin target temperature, and battery pack target temperature. In the results analysis, the performance of five feedback controllers is evaluated in step response and a driving cycle. Energy consumption of aerodynamic drag, rolling resistance, thermal management, regenerative braking, and auxiliary load are discussed in the parametric study. The results show that turning air conditioning system on could potentially reduce the EV range by 38–45 % at city driving condition. In addition, Ambient temperature shows significant nonlinear impact on EV range and the impact gets worse as temperature turns higher. For Tesla Model 3, when the ambient temperature rises from 30 °C to 35 °C and then to 40 °C, the range drops by 3.3 % and 13.4 %, respectively. Compared with ambient temperature, cabin temperature and battery pack temperature settings have less impact on the range. The code utilized in this study is made open source via Github (https://github.com/binxuAI/EV_TMS), which can be utilized as the guidance in the thermal management range impact analysis and concept design of electric vehicle.

Preliminary design and simulation of an innovative Rotary Supersonic Nozzles Expander apparatus for natural gas liquefaction and general refrigeration processes

An innovative method and a supersonic expansion apparatus proposed for the natural gas liquefaction process and the potential to use in general Refrigeration purposes, gases separation, CO2 capture and air conditioning. The current study presented the innovated apparatus features preliminarily, described its design basics and working principles, and outlined general schemes of approached method implementations. The apparatus named the Rotary Supersonic Nozzles expander. The apparatus designed on the basis of the compressible flow and the fundamentals of the Laval nozzle and the supersonic separation process. It is an Expansion bladeless turbomachinery utilizes the propulsion reaction principles of the Rocketry Engines. The numerical analysis and CFD simulations were conducted to investigate the influences of the nozzle backward reaction velocity on the supersonic flow distributions and to determine the enhancements achieved in the gas cooling and condensation processes by the proposed apparatus compared with the existing supersonic separators. CFD executed based on the anticipated nucleation theories and condensation models. Simulation results confirmed that fluid stagnation properties in the proposed apparatus exposed unacquainted behaviors during the rotational motion and their distributions diminished along the nozzles. The proposed apparatus obtained an extraordinary improvement in the supersonic expansion and condensation process. The estimated maximum nucleation rate 1.80707e + 037 m−3 s−1, which was about 10e + 14 times the existing rate in the statical nozzle at the same conditions. Similarly, the estimated maximum droplets number and mass transfer rate were about 10e + 08 and 14 times respectively. The obtained maximum liquid mass fraction was 0.6 and 5.75 times more than that achieved by the static nozzle. Furthermore, the estimated shaft power recovery was>50 % of the required power to obtain the same compression ratio.

Flexibility concept in design of advanced multi-energy carrier systems driven by biogas fuel for sustainable development

In this paper, a new and comprehensive multigeneration system is developed exploiting biogas fuel. The system is examined from the perspective of energy, exergy, exergoeconomic, exergoenvironment, and safety for supplying the energy demands of large buildings such as modern hospitals located near industrial places. Multi-objective optimization is applied along with a new concept of flexibility in the system considering these five indicators. The Brayton cycle and closed Brayton cycle for power generation, dual-loop organic Rankine cycle and ejector refrigeration for power and cooling production, multi-effect distillation unit for freshwater production, carbon dioxide absorption unit by microalgae for biodiesel production, water heaters for domestic heating production, and PEM electrolyzer for hydrogen production are integrated into the devised system. From the environmental point of view, using biogas fuel and absorption of carbon dioxide leads to the best environmental efficiency in the proposed system. Moreover, the safety facet is analyzed to lower the level of damage and risk in the system. Based on the results of the optimization, the net output power, air conditioning refrigeration, freezing, and heating are reckoned at 1864, 286.6, 75.89, and 398.9 kW, and the production of freshwater, hydrogen, biodiesel, and glycerol is predicted to be 2.111, 0.00038, 0.0088, and 0.00091 kg/s, respectively. Also, the system performance ratio, unit cost of product, exergy efficiency, environmental effect of product, and overall system risk are equal to 1.828, 40.58 $/GJ, 31.11%, 6232 mPts/GJ, and 1656 $/year.

Assessment on energy and exergy of combined supercritical CO2 Brayton cycles with sizing printed-circuit-heat-exchangers

The supercritical carbon dioxide Brayton cycle is one of the alternative thermal schemes for advanced energy systems. In this study, ammonia absorption Refrigeration-reheat supercritical carbon dioxide Brayton combined cycle is constructed, and the thermodynamic performance of reheat supercritical carbon dioxide Brayton cycle with ammonia absorption refrigeration cycle are analyzed. The characteristics of Brayton cycle and ammonia absorption refrigeration cycle configuring with Printed Circuit Heat Exchanger are analyzed. The result shows that under controlled freezing-point storage condition, optimized combined cycle energy and exergy efficiency is 46% and 64.98%, electricity output and refrigeration capacity is 11.4 MW and 1.78 MW. Under air-conditioning refrigeration condition, optimized combined cycle energy and exergy efficiency is 50.28% and 65.04%, and electricity output and refrigeration capacity is 11.4 MW and 3 MW. Compared with combined cycle performance before optimization, average improvement of cycle energy efficiency, exergy efficiency and exergy destruction is 4.19%, 0.73% and 3.64%, which shows obvious improvement of cycle performance after optimization. Comparative analysis of printed circuit heat exchanger applied at recuperator and subcooler shows that heat transfer performance of single-faced etched printed circuit heat exchanger in straight channel is better than that of double-faced etched printed circuit heat exchanger for same heat transfer and pressure drop.

Collaborative Control and Optimization Mechanism of Thermal Management of New Energy Vehicles

Global issues such as global warming, rising sea level, melting Arctic and Antarctic glaciers, deterioration of the natural environment, and depletion of fossil energy have attracted increasing attention. As the concept of environmental protection has become increasingly popular, the concept of new energy automobiles has been proposed to keep the heat up. Especially in recent years, with the advantages of energy conservation, environmental protection, and low noise, new energy automobiles have changed from concept to industry and have been generally accepted and recognized by consumers in the consumer market. The increasingly stringent energy crisis and emission regulations have put forward more stringent requirements for modern automobiles. The thermal management of the new generation of intelligent automobiles is not only limited to simply solving the problem of engine heat dissipation but also involves reliability, power, economy, emissions, and comfort. It is an important vehicle development technology with many performances such as performance. The integrated thermal management of new energy vehicles includes engine cooling, oil cooling, air conditioning refrigeration, HVAC heating, supercharged intercooling, low cycle thermal fatigue, and thermal damage. For new energy vehicles such as hybrid and pure electric vehicles, it also includes motor cooling, motor controller cooling, and power battery temperature control. For the purpose of vehicle thermal management optimization design, this paper innovatively proposes IVTM technical solutions, relying on multidimensional numerical calculation coupling and multiobjective collaborative optimization control to integrate system design, scheme evaluation, performance analysis, dynamic control, and collaborative optimization. Through the integrated thermal management collaborative control strategy based on the full operating conditions of the new energy vehicle, the comprehensive improvement of multiple evaluation indicators such as system design performance, thermal management, and control performance and economy is achieved.

Research on Vehicle Aerodynamics and Thermal Management Based on 1D and 3D Coupling Simulation

In order to ensure the full heat dissipation of heat exchangers, the opening of the grille should be large, which increases the wind drag of the whole vehicle. Most of the research on the grille only focuses on its impact on the heat dissipation of the engine compartment; there is little research on its influence on the performance of the thermal management system, because it is difficult to solve the real-time data interaction of different dimensional models. So we established the 1D and 3D strong coupling model. The biggest difference from other 1D and 3D coupling models is that we can use the interfaces reserved by the two kinds of software to realize real-time data interaction, and simultaneously analyze the 1D thermal management performance and 3D flow field and temperature field of the engine components. The coupling model is used to study three heat balance conditions. The results show that the heat-sinking capability of the cooling system is the worst under the climbing condition; and the refrigeration capacity of the air-conditioning system is the worst under the idling condition. According to the heat balance results and evaluation index priorities, we determine the simulation process. In this article, first the upper grille is gradually closed; then the flow field, temperature field and evaluation indexes are studied through the strong coupling model to obtain the analysis results of the upper grille; then based on the results, the lower grille is gradually closed, and the analysis results of the lower grille are obtained in the same way. The final simulation results show that on the premise of ensuring the performances of engine cooling system and air conditioning refrigeration system, the air drag coefficient is reduced by 17.5 counts compared with the original vehicle.

Energy-saving diagnosis model of central air-conditioning refrigeration system in large shopping mall

Aiming at the problems of extensive management and energy waste in the operation of shopping malls, this paper proposed a shopping mall building energy-saving diagnosis model based on an improved PSO-SVM neural network. Firstly, the operation data with good energy-saving characteristics were selected from the collected historical data of energy consumption by clustering algorithm as the data basis for the establishment of the model. Secondly, the Adaboost algorithm was used to optimize the PSO-SVM neural network to complete the model construction, and the energy-saving data was used to complete the training of the model. Finally, the judgment criteria for abnormal energy consumption were established, and the energy consumption situation at the current moment was diagnosed by using the trained energy-saving diagnosis model. The abnormal judgment criteria of energy consumption were used to analyze the diagnostic results, and the energy-saving diagnosis process was completed, which was verified by case analysis. Through case analysis and verification, the energy-saving rate of the energy-saving diagnosis model established in this paper has been increased from -1.1% to 11.9%, and the problem moments generated during the operation of air conditioning in shopping malls have been successfully diagnosed. The model established in this paper can not only find out the unreasonable conditions in the operation of the air-conditioning system, but also provide a reference for building energy-saving management and operation.

Predictions of European refrigerants place on the market following F-gas regulation restrictions

• Refrigerant place on the market (POM) in Europe will suffer a significant cut in 2021. • Up to 2020, European refrigerants POM has been respected, despite the sustained demand. • Meeting the 2021 quota will be challenging due to inertia in the adoption of POM mitigation measures. • Industrial, stationary and commercial refrigeration will concentrate more than half of the total refrigerant demand, measured in CO 2 e. The European Union (EU) Regulation on fluorinated greenhouse gases (F-gases) has encouraged to reduce gradually the number of hydrofluorocarbons (HFC) that can be placed on the market (POM) to 21% of the baseline level in 2030. However, to this day, the EU refrigeration, air conditioning and heat pump (RACHP) market is still dominated by these substances. This study describes a methodology to estimate the refrigerant demand by refrigeration, air conditioning, and heat pumps available to the EU customers until 2030. The work is based on the most relevant current statistical data, refrigerant distribution (R134a, R404A, R407C and R410A), and future technology acceptance and trends. The study presents a refrigerant demand grow scenario and provides a basis for a closer market follow-up to facilitate refrigeration industry stakeholders' decision-making. The results indicate that by 2021 will be challenging to accomplish the fluorinated gas quota considering the current HFC phase-down process. However, by 2030, the transition is possible in the EU, assuming the additional measures to mitigate the leakage from already installed equipment will be taken. By that time, natural refrigerants, including CO 2 , ammonia, and hydrocarbons, can dominate the market. However, the share of HFC or HFC/HFO mixtures in operation is still significant (R32 or mixtures with similar behaviour, and R404A low flammability alternatives). Consequently, industrial and commercial refrigeration (large scale applications) will concentrate approximately half of the GWP weighted CO 2 e, negligible direct emissions for domestic refrigeration or mobile air conditioning, dominated by natural refrigerants pure HFO refrigerants, respectively.

Ecoenergetic Comparison of HVAC Systems in Data Centers

The topic of sustainability is of high importance today. Global efforts such as the Montreal Protocol (1987) and the Kigali Amendment (2016) are examples of joint work by countries to reduce environmental impacts and improve the level of the ozone layer, the choice of refrigerants and air conditioning systems, which is essential for this purpose. But what indicators are to be used to measure something so necessary? In this article, the types of air conditioning and GWP (Global Warming Potential) levels of equipment in the project phase were discussed, the issue of TEWI (Total Equivalent Warming Impact) that measures the direct and indirect environmental impacts of refrigeration equipment and air conditioning and a new methodology for the indicator was developed, the TEWI DC (DC is the direct application for Data Center), and using the formulas of this new adapted indicator it was demonstrated that the TEWI DC for Chicago (USA) was 2,784,102,640 kg CO2/10 years and Curitiba (Brazil) is 1,252,409,640 kg CO2/10 years. This difference in value corresponds to 222.30% higher annual emissions in Chicago than in Curitiba, showing that it is much more advantageous to install a Data Center in Curitiba than in Chicago in terms of environmental impact. The TEWI indicator provides a more holistic view, helping to combine energy and emissions into the same indicator.

Optimal Shape of Non-Linear Partially Wet Annular Fins for Maximum Efficiency

Heat exchangers with annular finned-tube type and partially wetted condition are utilized widely in engineering systems, such as air-conditioning systems and refrigeration systems. In addition, the physical properties of fin materials should be considered as functions of temperature in reality and thus become a non-linear problem. Based on the above two conditions, an optimal partially wet annular fin design problem, with temperature-dependent thermal properties of the fin, to yield optimal fin efficiency was investigated in the present work, which has not been examined previously and it is the novelty of this study. An iterative regularization algorithm using the conjugate gradient method (CGM) is considered as the optimization tool based on the desired fin efficiency under a fixed fin volume constraint. The partially wet annular fin condition can result if the relative humidity of surrounding air is between 80 and 90%. Finally, the optimal fin shape, with the highest computed efficiency among examined fins under identical operational conditions, can be obtained. It is found that when the Biot numbers for ambient air (Bia) and relative humidity (φ) increased, the optimum computed fin efficiency and interfacial radius between wet and dry fin domains (rwd) will be increased, and the estimated optimum fin shape also changed. However, the shape of optimal fin remained approximately unchanged when the Biot numbers for the inner tube (Bii), the thermal conductivities of the tube (kw) and fin (kf) varied. It reveals that Bii, kw and kf have an insignificant influence on the optimal shape of the annular fin in a partially wet condition.

Simulation of Mixing Synthetic with hydrocarbons Refrigerant to Reduce the Value of Global Warming Potential with Refprop Software

The problem of global warming or called GWP (Global Warming Potential) that occurs in the earth’s atmosphere, one of which comes from synthetic refrigerants used in household air-conditioning refrigeration machines. R410A is a refrigerant that still contains GWP: 1942. Hydrocarbon refrigerant is a refrigerant that does not contain ODP (Ozone Depleting Potential) and a very small GWP. By using ref prop software, the mixing process can be simulated to obtain refrigerants that have characteristics similar to R410A. Mixing using R32 / R290 ingredients varied with percentage compositions ranging from 50/50, 40/60, 30/70, 20/80, and 10/90. From the simulation results, a mixture approaching R410A with 10/90 composition with COP: 3.85 for R410A and 5.76 for 10/90 mixture was obtained. Compression ratio: R410A: 2.8 and for mixed refrigerants 10/90: 1.8. The refrigerant effect of mixed refrigerants is 10/90: 264,13, R410A: 161,68. By using this refrigerant mixture can reduce the GWP and improve the performance of the Air Conditioning cooling system so that it has a reduced GWP value that can be obtained significantly and has a large enough potential to replace the R410A.