JournalTOCs

International Journal of Air-Conditioning and Refrigeration
Journal Prestige (SJR): 0.561

Citation Impact (citeScore): 1
Number of Followers: 17

Hybrid journal (It can contain Open Access articles)
ISSN (Print) 2010-1325 - ISSN (Online) 2010-1333
Published by World Scientific

[119 journals]

Performance of a Flat-Tube Louvered-Fin Automotive Condenser with R1234yf
- Authors: H. M. Gurudatt, G. S. V. L. Narasimham, B. Sadashive Gowda
  Abstract: International Journal of Air-Conditioning and Refrigeration, Ahead of Print.
  Numerical simulation of a mini-channel, flat-tube, louvered fin, automotive condenser is performed to study the heat rejection rate, pressure drop and performance of the heat exchanger. The simulation study is carried out for the refrigerant R1234yf. The properties of R1234y are obtained from REFPROP software. The moist air properties are calculated from those of dry air and water vapor using suitable correlations. To select the input data, the cycle performance is carried out for a standard vapor compression refrigeration system working with R1234yf between the temperature limits of [math]C on the low-pressure side and [math]C on the high-pressure side. The condensation process is taken into account in three sections, namely, the superheated, two-phase and the subcooled regions. A custom code is prepared in MATLAB to solve the simultaneous equations of heat transfer from refrigerant to inside tube wall, inside tube wall to outside tube wall and outside tube wall to moist air. The simulation results show the sensible heat transfer during desuper heating to be very small compared to the condensing region. Results are reported for the pressure variation along the refrigerant flow passage in the desuper heating, two-phase and subcooling regions. The heat-transfer coefficient is found to be the highest in the two-phase region for higher dryness fractions. The effect of inlet air velocity is less compared to that of the inlet air temperature on the heat rejection rate.
  Citation: International Journal of Air-Conditioning and Refrigeration
  PubDate: 2021-01-18T08:00:00Z
  DOI: 10.1142/S2010132521500024
A Novel Technique for Improving the Performance of Ammonia Absorption
Refrigeration Cycle
- Authors: M. Hemeda Shaker, M. S. Abd-Elhady, M. A. Halim
  Abstract: International Journal of Air-Conditioning and Refrigeration, Ahead of Print.
  The world is now living in an energy crisis. Refrigeration and air-conditioning systems have become the basics of daily life in various fields and accordingly, it cannot be dispensed. Refrigeration machines and air-conditioning systems are the most energy-consuming systems, independent on the application whether it is domestic, commercial, industrial or medical. Therefore, using cooling systems which are powered by thermal energy, e.g., solar energy, can save a lot of electrical energy. Absorption refrigeration system is an example of a refrigeration system powered by heat energy. However, the system problem here is that it has low coefficient of performance (COP). The objective of this research is to improve the COP of the ammonia absorption cycle. This is done in the absorber unit by improving the absorption of the refrigerant ammonia into the ammonia–water solution. The absorption efficiency is improved by using (1) a stirrer pump to improve mixing, (2) sprayers to increase the contact area between ammonia and ammonia–water solution and (3) continuous cooling of the solution during the absorption process via an external heat exchanger. The COP of the ammonia absorption cycle has increased from 0.48 to 0.715, i.e., by 49%. This is due to the improvement of the absorption of the ammonia into the ammonia–water solution.
  Citation: International Journal of Air-Conditioning and Refrigeration
  PubDate: 2021-01-18T08:00:00Z
  DOI: 10.1142/S2010132521500036
A Review of Models for Estimation of Moisture Evaporation Rate from
Clothes Inside a Clothes Dryer
- Authors: Mehdi Rasti, Ji Hwan Jeong
  Abstract: International Journal of Air-Conditioning and Refrigeration, Ahead of Print.
  Heat pump tumble dryers, air-vented dryers and condenser dryers are widely used as clothes dryers. Clothes dryers use hot air to absorb moisture from textiles to get them dry after a wash by passing drying air through the drum. To simulate the drying process of clothes in the drum and to obtain the moisture evaporation rate, it is necessary to use an accurate model to predict the moisture transfer coefficient from the textile to the air in the drum as well as the mass transfer area between the drying air and the textile. In this study, a comprehensive review of the literature on the prediction of the moisture evaporation rate inside the drum of a clothes dryers was conducted. It was found that researchers generally used constant values, fitting models, dimensionless correlations, and Chilton–Colburn analogy to predict the area–mass transfer coefficient. Moreover, few researchers used the effectiveness model for the prediction of moisture evaporation rate. The comprehensive review of the literature showed that all of the previous models for prediction of the moisture evaporation rate have some limitations in terms of generality or accuracy. Therefore, the development of a new accurate model for prediction of the moisture evaporation rate inside the drum of clothes dryers is crucial.
  Citation: International Journal of Air-Conditioning and Refrigeration
  PubDate: 2021-01-08T08:00:00Z
  DOI: 10.1142/S2010132521300019
Author Index (Volume 28)
- Abstract: International Journal of Air-Conditioning and Refrigeration, Volume 28, Issue 04, December 2020.
  
  Citation: International Journal of Air-Conditioning and Refrigeration
  PubDate: 2020-12-29T08:00:00Z
  DOI: 10.1142/S2010132520990011
  Issue No: Vol. 28, No. 04 (2020)
Rotary Compressor Performance at Low Ambient Temperatures
- Authors: S. Lowrey, G. Reboux
  Abstract: International Journal of Air-Conditioning and Refrigeration, Ahead of Print.
  Small rotary compressors are used in domestic heat pump appliances, for example, in domestic dehumidifiers and heat pump clothes dryers. Compressor performance curves provided by the manufacturer can be based on testing at relatively high ambient temperatures, in some cases as high as 35°C. This can be much higher compared with the ambient temperature in which the compressor operates when, for example, it is installed in a domestic dehumidifier which can operate in ambient temperatures as low as 10°C. We have developed a compressor calorimeter to test a small R134a rotary compressor extracted from a commercial domestic dehumidifier and use this to measure compressor performance parameters including the isentropic and volumetric efficiencies and the compressor heat loss fraction. The performance testing has been carried out at ambient temperatures 10°C, 15°C, 20°C and 25°C for a fixed relative humidity of 70% to compare how the compressor performance varies with the ambient temperature, and to determine how well the compressor performs outside of the performance envelope provided by the manufacturer. The results show that isentropic and volumetric efficiency of these small compressors is relatively insensitive to variation in ambient temperature, even outside of the performance envelope provided by the manufacturer. However, the compressor heat loss fraction can, on average, double from 15% to 30%, between operation at ambient 25°C and ambient 10°C. The data obtained in this work is used to construct compressor sub-models for certain ambient temperatures. We show how these sub-models can be used to improve a domestic dehumidifier model for operation at low ambient conditions within the evaporator frosting regime and good agreement is obtained between experimental and simulated data. The authors are not aware of a domestic dehumidifier model designed to work at ambient temperatures within the frosting regime.
  Citation: International Journal of Air-Conditioning and Refrigeration
  PubDate: 2020-12-24T08:00:00Z
  DOI: 10.1142/S2010132520500376
Optimized Refrigerant Flow Rate and Dimensions of the Ejector Employed in
a Modified Ejector Vapor Compression System
- Authors: Dishant Sharma, Gulshan Sachdeva, Dinesh Kumar Saini
  Abstract: International Journal of Air-Conditioning and Refrigeration, Ahead of Print.
  This paper presents the analysis of a modified vapor compression cooling system which uses an ejector as an expansion device. Expanding refrigerant in an ejector enhances the refrigeration effect and reduces compressor work. Therefore, it yields a better coefficient of performance. Thermodynamic analysis of a constant area ejector model has been done to obtain primary dimensions of the ejector for given condenser and evaporator temperature and cooling capacity. The proposed model has been used to design the ejector for three refrigerants; R134a, R152a and R1234yf. The refrigerant flow rate and the diameters at various sections of the ejector have been obtained by doing numerical modeling in Engineering Equation Solver (EES). Refrigerant R1234yf demanded the highest diameter requirements at a fixed 5∘C evaporator temperature and 40∘C condenser temperature for a given range of cooling load. Both primary and secondary refrigerants flow rates are higher for R1234yf followed by R134a and then R152a.
  Citation: International Journal of Air-Conditioning and Refrigeration
  PubDate: 2020-12-24T08:00:00Z
  DOI: 10.1142/S2010132520500388
Multi-Objective Optimization of Cascade Refrigeration System Using the
- Authors: Vaibhav Jain, Rajiv Rawat, Gulshan Sachdeva, Vikas Kumar
  Abstract: International Journal of Air-Conditioning and Refrigeration, Ahead of Print.
  This work conceives the performance of vapor compression cascaded refrigeration system (CRS) from the exergy, safety and thermal inventory points of view employing the theory of effective temperature ([math] than environment temperature ([math] in Gouy–Stodola equation. Comparative results show that the actual irreversible loss in CRS is 8.1% higher. Further, advanced exergy analysis results showed that 17.985[math]kW irreversible loss (out of 33.737[math]kW irreversible loss) in the system is evadable with improvement in the system design. Besides, the vulnerability of toxic fluid R717 is reported in terms of the total risk level. Moreover, the economy matter is expressed in terms of its total thermal inventory. At the base case, total risk level and total thermal inventory are determined to be 454.3 US$ and 48.86[math]kW/K, respectively. First, sensitivity analysis is carried out to evaluate the variation in irreversible loss, total risk level and thermal inventory at different evaporator and condenser temperatures with different degrees of overlap (decision variables). A total of nine simulations are designed using the Taguchi technique. Later, multi-objective optimization is employed. The optimization process reduced the total irreversibility and annual risk level of CRS by 10.2% and 8.9%, respectively, with 6.8% increase in thermal inventory.
  Citation: International Journal of Air-Conditioning and Refrigeration
  PubDate: 2020-12-19T08:00:00Z
  DOI: 10.1142/S2010132520500364
Miniaturized Traveling-Wave Thermoacoustic Refrigerator Driven by
Loudspeaker: Numerical Design
- Authors: Oday S. Mahmood, Abdul Mun’em A. Karim, Samir Gh. Yahya, Itimad D. J. Azzawi
  Abstract: International Journal of Air-Conditioning and Refrigeration, Ahead of Print.
  Ordinary refrigeration systems such as vapor-compression refrigerators are the commonly used devices in industry, mostly for their high efficiencies. However, they make a significant contribution to the depletion of Ozone and global warming due to their operational refrigerants. Hence, thermoacoustic refrigeration can be a great alternative candidate which uses inert gases such as air, helium and nitrogen as the primary refrigerant. Thermoacoustic refrigerators convert the acoustic power (sound waves) into a thermal effect (cooling power). Thermoacoustics can be counted as a new technology that has a strong potential toward the development of the thermal applications. This study aims to design and fabricate miniaturized traveling wave thermoacoustic refrigerator which can be driven by an ordinary loudspeaker. The optimized numerical design of the refrigerator shows an overall efficiency (cooling power over input electricity) of nearly 66% at a temperature difference of 25[math]K (between cold and ambient heat exchangers). The maximum estimated cooling power is 65[math]W at coefficient of performance (COP) of 2.65.
  Citation: International Journal of Air-Conditioning and Refrigeration
  PubDate: 2020-12-05T08:00:00Z
  DOI: 10.1142/S2010132520500352
Assessment of a Simpler Friction Factor in an Algebraic Solution for
Adiabatic Coiled Capillary Tubes
- Authors: Thiago Torres Martins Rocha, Sara Isabel De Melo Resende, Hélio Augusto Goulart Diniz, Fernando Antônio Rodrigues Filho, Raphael Nunes De Oliveira
  Abstract: International Journal of Air-Conditioning and Refrigeration, Ahead of Print.
  In this work, the performance of an existing algebraic solution for adiabatic coiled capillary tubes, in subcritical cycles, is investigated. However, the C-M&N friction factor, commonly used, was replaced by Schmidt friction factor, which is less complex. Two existing dimensionless correlations were also evaluated for comparison. To assess the effect of altering the friction factor, experimental data collected in the literature were used as reference. Analyzing the present results and that with C-M&N friction factor, it was observed that adopting the Schmidt friction factor does not cause a relevant impact on the solution. The deviations of the predicted versus experimental mass flow rates were comprised in a range between –8% and 12%, with average deviation (AD), absolute average deviation (AAD) and root mean square (RMS) error of –0.1%, 2.7% and 3.4%, respectively. The empirical correlations presented unsatisfactory results, with maximum deviation around 40%. Therefore, it was concluded that using the Schmidt friction factor is adequate to reduce the complexity of the algebraic solution and to maintain the accuracy.
  Citation: International Journal of Air-Conditioning and Refrigeration
  PubDate: 2020-11-25T08:00:00Z
  DOI: 10.1142/S2010132520500339
The Effects of Hydrophobicity and Drainage Velocity on Water Retention
Behaviour in Porous Media: A Computational Study
- Authors: K. W. Yong, P. B. Ganesan, E. Hamidi, S. N. Kazi, S. Ramesh
  Abstract: International Journal of Air-Conditioning and Refrigeration, Ahead of Print.
  The present study investigates the water retention behavior in two different types of porous media, i.e., porous metal — a type of metallic foam and ideal geometry. The present study uses computational fluid dynamics (CFD) to model a decreasing water level in a reservoir consisting of a stationary porous medium beneath the water surface at initial stage. It mimics the setup of dynamics dip-testing which measures the amount of retained water for different types of fins-tubes heat exchangers. The study varies parameters like static contact angle ([math]) and drainage velocity ([math]). The literature review summarizes the unique water retention behaviors for different types of heat exchangers and the findings of the present study. Furthermore, the present study proposed new parameters for evaluating the structural variations in porous metal that explains the water saturation distribution in detail. The evaluation method could provide an insightful idea for performing the quality control check on metallic foam.
  Citation: International Journal of Air-Conditioning and Refrigeration
  PubDate: 2020-11-23T08:00:00Z
  DOI: 10.1142/S2010132520500340
Experimental Evaluation of Window-Type Air-Conditioning Unit with New
Expansion Device and R404A Alternative Refrigerant
- Authors: Ali K. Shaker Al-Sayyab
  Abstract: International Journal of Air-Conditioning and Refrigeration, Ahead of Print.
  In this study, the performance of a window-type air-conditioning unit with an alternative, ozone-friendly refrigerant was enhanced by incorporating a nozzle instead of a capillary tube as an expansion device. An experimental evaluation was adopted on a 1.5 RT window-type air-conditioning unit with a controlled environmental zone. According to operating conditions, an ANSYS-Fluent program was used to predict an appropriate nozzle size for a lower pressure ratio. The refrigeration cycle model was simulated using the Engineering Equation Solver (EES).27 The results showed that using a nozzle of 30[math]mm length and inner and outer diameters of 9 and 2[math]mm, respectively instead of the capillary tube with R404A reduces compressor power consumption by 7.7% and increases the coefficient of performance (COP) by 7.4%.
  Citation: International Journal of Air-Conditioning and Refrigeration
  PubDate: 2020-10-27T07:00:00Z
  DOI: 10.1142/S2010132520500315
Potential Alternative Materials used in Evaporative Coolers for
Sustainable Energy Applications: A Review
- Authors: Shiva Kumar, Jay Singh, Jogendra Siyag, Srikar Rambhatla
  Abstract: International Journal of Air-Conditioning and Refrigeration, Ahead of Print.
  In hot climatic conditions, increased energy consumption toward cooling has led to the development of evaporative coolers. The performance of evaporative cooler depends on the various material and operating parameters. Type of material selected for cooling pad is the most important factor among them. In this study, various types of cooling pad materials have been discussed based on their potential benefits, influence on the cooling performance like characteristics wettability, porosity, water holding capacity and cost. It is seen that organic- and fiber-based materials have been extensively used, whereas the studies related to materials based on plastics and metals are limited. Ideal material properties to be possessed by a good pad material have been discussed. Prospects and future scope for further research have been identified. Hence, this review paper certainly throws some light on the selection criteria for a potential alternative evaporative cooling pad material that shows the maximum cooling performance and helps achieve sustainable cooling in buildings.
  Citation: International Journal of Air-Conditioning and Refrigeration
  PubDate: 2020-10-21T07:00:00Z
  DOI: 10.1142/S2010132520300062
Effects of Nanostructure Additives on Supercooling and Freezing of
Distilled Water
- Authors: Donggyu Lee, Donghyun Kim, Chaedong Kang
  Abstract: International Journal of Air-Conditioning and Refrigeration, Ahead of Print.
  The phenomenon of supercooling, which prevents freezing of water below the freezing point, is an obstacle to the production of inexpensive ice. In the case of ice heat storage systems using bio-preservation, low-temperature refrigeration of food and ice capsules in the HVAC industry, the supercooled water in capsules that indirectly come into contact with the outside is one of the problems that must be solved to maintain energy costs and the quality of food or organs. To improve this, experimental evaluation of additives that serve as crude nuclear agents is needed. However, research on this area needs to be supported because the types of additives are limited and their physical properties are unstable. In this paper, the effect of distilled water containing an additive of average diameter nanometer size on solution (frozen) supercooled below the freezing point was investigated. The supercooling time and supercooling level of each specimen were analyzed after addition of kaolin, strontium hydroxide, oxidizing mineral and nano-sized single-wall carbon nanotubes (SWCNT) as mineral fine particles in the distilled water. As a result, it has been confirmed that kaolin and SWCNT can be used as nuclear materials to release supercooling of water. In addition, when kaolin, a mineral fine particle, is used as a nuclear material, its size affects the performance of nuclearization. This confirmed the impact of nuclear material particle size and structure on overcooled emissions.
  Citation: International Journal of Air-Conditioning and Refrigeration
  PubDate: 2020-10-21T07:00:00Z
  DOI: 10.1142/S2010132520500297
Analysis of Additive Alignment in a [math] Elbow Channel
- Authors: Hoang Minh Khoa Nguyen, Dong-Wook Oh
  Abstract: International Journal of Air-Conditioning and Refrigeration, Ahead of Print.
  Short-fiber reinforced polymer composites have been widely used in industrial applications due to high strength-to-weight ratio, versatile manufacturing process, and etc. The alignment of fiber type additives plays an important role in the mechanical properties of a composite material. In this paper, an injection molding process was imitated with a liquid polymer composite flow inside a [math] elbow channel. We performed a flow visualization experiment and analyzed the additive alignment of carbon fiber flowing in the polydimethylsiloxane (PDMS) medium. By analyzing the flow visualization images, the angle changes at the corner region of the elbow channel were calculated. At the corner region, the change of passage direction leads to the change of fiber orientation. It was observed that near to the convex region, fibers have angle change values larger than the fibers traveling near to the concave region.
  Citation: International Journal of Air-Conditioning and Refrigeration
  PubDate: 2020-10-21T07:00:00Z
  DOI: 10.1142/S2010132520500327
Energy, Exergy, and Exergoeconomic Analysis of Solar Thermal Power Plant
Hybrid with Designed PCM Storage
- Authors: Maryam Fani, Nima Norouzi, Molood Ramezani
  Abstract: International Journal of Air-Conditioning and Refrigeration, Ahead of Print.
  The tendency of renewable energies is one of the consequences of changing attitudes towards global energy issues. As a result, solar energy, which is the leader among renewable energies based on availability and potential, plays a crucial role in thoroughly filing global needs. Significant problems with the solar thermal power plants (STPP) are the operation time, which is limited by daylight and is approximately half of the power plants with fossil fuels, and the capital cost. In the present study, a new suggested sketch of adding latent heat storage (LHS) filled with commercial phase change material (PCM) to a 500-kW STPP case study has been investigated. Solar system details and irradiation amounts for a case study, including total and beam radiation have been determined. Also, the theoretical energetic and exergetic analysis of adding PCM storage to STTP is conducted, which showed a 19% improvement in the exergetic efficiency of the power plant to reach 30%. Besides, an optimized storage tank and appropriate PCM material have been investigated and selected concerning the practical limitations of the case study. By designing a new cycle, the LHS will be charged during daylight and will be discharged at night, doubling power plant operation time up to 2500[math]h. Finally, exergoeconomic survey of STPP hybrid with PCM storage was carried out using Engineering Equation Solver (EES) program with genetic algorithm (GA) for three different scenarios, based on eight decision variables, which led us to decrease final product cost (electricity) in optimized scenario up to 30% compared to base case scenario from 28.99 to 20.27 $/kWh for the case study. Also, a comparison is made to demonstrate the effectiveness of the proposed new cycle on 250, 500, 1000, and 2000 kW STTPs.
  Citation: International Journal of Air-Conditioning and Refrigeration
  PubDate: 2020-10-19T07:00:00Z
  DOI: 10.1142/S2010132520500303