Liquid-suction Heat Exchanger Research Articles

Investigation of an automobile air-conditioner with a liquid-suction heat exchanger using R134a and R1234yf

Air-conditioning systems (ACs) are essential in hot and humid climates to ensure acceptable ambient air quality as well as thermal comfort for buildings users. It is essential to improve refrigeration system performance without increasing the effects of global warming potential (GWP) and ozone depletion potential (ODP). The main objective of this study is to evaluate the performance of an air conditioning system that operates with a liquid suction heat exchanger (LSHX) through implementing refrigerants with zero OPD and low GWP (i.e., R134a and R1234yf). Liquid suction heat exchanger (LSHX) was added to an automobile air conditioning system (AACS).When Liquid suction heat exchanger was added to the cycle, primary results indicated that an enhancement in the cycle coefficient performance (COP) by 25.2 %and 17.3% for R134a and R1234yf respectively, and decreasing in mass flow rate of the refrigerants used (m ̇_r). Also increasing in refrigeration effect (RE) by 4.2% and 2.3% for R134a and R1234yf respectively. Presence of LSHX caused increasing in heat rejected by condenser (Qcond.) according to increasing in sub-cooling degree and decreasing in compressor work (Wcomp.), increasing in condenser exergy destruction (X. des. cond.) and thermostatic expansion device (TXV) exergy destruction, but decreasing in compressor and evaporator. Summary of previous experimental and numerical studies is presented as well.

PENGARUH LIQUID SUCTION HEAT EXCHANGER TERHADAP KINERJA SISTEM PENDINGIN PADA MESIN PORTABLE CHILLER

When the Covid-19 pandemic occured, most of the industries and public facilities were not used properly, but the cooling machines was still used, resulting in large consumption of power and electrical energy. Along with high energy consumption where the availability of energy is running low, savings are needed. As an alternative so that the cooling machine can save energy is to use the subcooling method, namely the addition of a liquid suction heat exchanger on a spiral portable chiller with 29 spirals. Furthermore, the refrigerant used in the portable chiller is R407c. This study aims to determine the effect and effectiveness of Liquid Suction Heat Exchanger on a portable chiller. The results obtained are the coefficient of performance on the non-Liquid Suction Heat Exchanger portable chiller is 4,699 with a cooling capacity of 6,668 kW and compressor performance of 1,419 kW while the portable chiller with the addition of Liquid Suction Heat Exchanger, the Coefficient Of Performance obtained is 5,197 with a cooling capacity of 6,719 kW and compressor performance of 1,219 kW. From the calculation above, the use of a liquid suction heat exchanger in a portable chiller can increase the cooling capacity by 1,97 %.

Experimental Investigation of Using Liquid Suction Heat Exchanger with Condensed Cold-Water on the Performance of Air Conditioning System

This paper reports experimental investigation of using liquid suction heat exchanger (LSHX) with condensed cold-water (LSHX-CW) on the performance of a split type room air conditioning. To this end, we used a large room of a residential house of 64 m3 equipped with a 2-tons conventional commercial split-type air conditioner fitted with R22. The coaxial design of LSHX-CW allows to exchange heat between the vapor and liquid refrigerants in the center part and condensed water and the warm liquid refrigerant on the outer part. LSHX-CW was well insulated on the outside to reduce heat transfer with ambient. The air conditioning was tested several times for three scenarios namely, conventional system, system with LSHX alone and LSHX with condensed water LSHX-CW. Experimental results showed that the use of LSHX-CW improved the performance of air conditioning noticeably when compared to the use of LSHX alone. The maximum LSHX-CW effectiveness was 7.67%. The pressure discharge line and electricity consumed decreased by 8.23% and 9.40% respectively.

Thermodynamic Analysis of Eco-Friendly Refrigerant Mixtures as an Alternative to HFC-134a in Household Refrigerator

Nowadays, research has been focused on refrigerants from Hydrofluorocarbons (HFCs), which are not harmful to the ozone layer. Because of replacing refrigerants from chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). HFCs are used in many applications, including refrigerants, aerosols, solvents, and blowing agents for insulating foams. However, some HFCs have relatively high global warming potential (GWP) and are subject to further examination due to growing concerns about global climate change. The present work’s main objective is to select eco-friendly refrigerants from AC5, R430A and R440A, combining two or more refrigerants from HC, HFC and HFO groups as a direct substitute HFC-134a in a household refrigerator. The performance of the domestic refrigerator with liquid suction heat exchanger (LSHX) was compared in terms of compressor discharge temperature, coefficient of performance (COP), volumetric cooling capacity (VCC), and power consumption of a compressor. It was found that the average COP of R440A and R430A was higher by approximately 2.5% and 1.47% than HFC-134a. However, the COP of AC5 was 6.1% lower than that of HFC-134a. The VCC of R430A is almost equal to HFC-134a. The results also show that AC5, R440A and R430A consume less power than HFC-134a. The compressor outlet temperature with R440A, AC5 provide higher values than HFC-134a, which affects the compressor life. The best overall performance was achieved with the refrigerant R430A in the household refrigerator and suggested an alternative to HFC134a, which also has a very low GWP from the environmental safety perspective.

Performance enhancement of a vapor compression refrigeration system using R134a/MWCNT-oil mixture and liquid-suction heat exchanger equipped with twisted tape turbulator

Abstract This study investigates the performance attributes of a vapor compression refrigeration system (VCRS) with employing R134a/MWCNT-oil mixture and liquid-suction heat exchanger (LSHE) with/without twisted tape turbulator (TTT). The tests are done at different cycle pressure ratios (6.55–10.12), TTT twist ratios (1 ≤ λ ≤ 4), and nanoparticles’ mass concentrations (0 ≤ φ ≤ 0.5%). The experiments state that the exergy destruction rates are reduced by employing LSHE, TTT with reducing its twist ratio, and engaging R134a/MWCNT-oil mixture with increasing the MWCNTs loading, besides growing the cycle pressure ratio. Compared to the simple VCRS, the maximum enhancements in the COP and exergy efficiency (ηEx) of the VCRS are 37.3% and 126.5%, respectively, while compared to the simple LSHE, its effectiveness is improved by 97.9% obtained by simultaneously applying LSHE with TTT of λ = 1 and R134a/MWCNT-oil mixture of φ = 0.5%. Correlations are supplied to predict the COP and ηEx of the VCRS besides the effectiveness of LSHE.

Case study of liquid suction heat exchanger in a mechanical refrigeration system using alternative refrigerants

This paper investigates the effect of adding a liquid-suction heat exchanger on the performance of a mechanical refrigeration system using alternative refrigerants. Engineering Equation Solver (EES) was used to simulate a mechanical refrigeration system in two configurations: modified system with liquid-suction heat exchanger and system without liquid-suction heat exchanger. The results revealed that the liquid-suction heat exchanger has a significant effect on the system performance as it influences the subcooling and superheating temperatures. The results also showed that the highest value of the coefficient of performance (COP) was achieved by the modified system with refrigerant type R134a, COP was about 7% and 12% higher than that of refrigerants R600a and R22 respectively. It also presented that R600a has high response to increase the refrigerant effect when the liquid-suction heat exchanger is used. R600a is good alternative refrigerant and it can be used in the mechanical refrigeration system, but its COP is lower than that of R134a.

Exergy and energy analysis of low GWP refrigerants in the perspective of replacement of HFC-134a in a home refrigerator

The present work focusses on comparison of several low Global warming potential (GWP) refrigerants in search of possible alternatives to a refrigerant HFC-134a of a home refrigerator without any modifications. A computational mathematical model is developed and thermodynamic analysis has been carried out to investigate the influence of Evaporator temperature on the performance characteristics like Volumetric Cooling Capacity (VCC), Compressor power consumption, COP, and Compressor discharge temperature at two different Condenser temperatures (25°C and 45°C). By exergy analysis Exergetic efficiency, Exergy destruction ratio, and Efficiency defect across different components of the Vapour compression refrigeration system are also evaluated. Comparison is made between different refrigerants mentioned above. Results obtained revealed that the refrigerants HFO- 1234yf and HFC-152a can be a good replacement of HFC-134a refrigerant without any modifications. Condenser and Liquid suction heat exchanger (LSHX) have the highest and the lowest Efficiency defect respectively, among all the system components of a home refrigerator.

Performance Comparison of a Low GWP Refrigerants as Alternatives to R134a in a Refrigerator with and without Liquid-Suction Heat Exchanger

The usage of refrigerators and air conditioners are more prevalent in a domestic environment now-a-days. Improving the efficiency of these devices can be considered as an important step to reduce their energy consumption. Currently, in India, most refrigerators work with HFC-134a as a refrigerant. The GWP value of HFC-134a is around 1430.Therefore, there is a greater demand to replace HFCs with low GWP refrigerants. In this document, the comparison of the performance of a refrigerator without fluid intake heat exchanger (LSHX) with low GWP refrigerants and the results are compared with HFC-134a performed. The low GWP refrigerants used in the test are: hydrocarbon-propane (R290) and isobutane (R600a), the pure hydrocarbons are HFC-134a and HFC-152a and the refrigerants are hydrofluoroolefins 1234yf and 1234ze (E). All have been tested without making changes in the system. The entire examination was carried out in the same system under the same working conditions.

A REVIEW ON SUB-COOLING IN VAPOR COMPRESSION REFRIGERATION CYCLE FOR ENERGY SAVING

Vapor compression refrigeration cycle (VCRC) is widely used in refrigeration and air conditioning (R&A) systems. Sub-cooling is used to improve the coefficient of performance (COP) of the R&A system by enhancing the cooling capacity. This paper presents various sub-cooling methods, which have been established and applied to enhance the performance of the VCRC. In a simple cycle of VCRC, the exit of the condenser is at saturated liquid line. Further cooling of the exit condenser to the sub-cooled region can result in an increase in the cooling capacity due to low vapor quality refrigerant entering the evaporator. As a result, the refrigerant absorbs more heat in the evaporator. The lower the quality of the refrigerant entering the evaporator, the higher the cooling capacity that is produced by the evaporator. This cooling capacity improvement results in an increase in the COP. In the present study, four sub-cooling methods are reviewed, which are liquid-suction heat exchanger, dedicated mechanical sub-cooling, integrated mechanical sub-cooling and condensate assisted sub-cooling. The advantages and drawbacks of each method, as well as future research direction in this research domain were discussed in detail.

Refrigeration System Performance by Inserting Twisted Strip in Condenser Along With Liquid Suction Heat Exchanger

This paper gives preliminary aftereffects of VCR (Vapor Compression Refrigeration) go through setting twisted strip inside the condenser tube, using liquid suction warmth exchanger (lshe), and R134a as refrigerant in this cycle. examination executed on basic condenser tube with 3 different bended point strips verified in condenser tubes on the element of liquid suction heat exchanger for subcooling to remove suitable COP from cutting edge VCR machine. inside the proposed, lshe are taken through using each the procedures, strip focuses, α=a hundred,one hundred forty &one hundred eighty by methods for undeniable chamber and with subcooling. The proposed check has additionally made a through and through appraisal of COP, refrigeration influence, charge of impact and capability. in the communicated test; it's miles put that the drop in weight is 16% for the twisted strip tube condenser while in evaluation to customary condenser tube. other than it's in like manner seen that condenser with bowed strip implanted increments quick rot inside the temperature of evaporator than basic chamber. The effect and viability of misshaped strip verified cylinder condenser is unnecessary as strain drop falls in the condenser and decline of evaporator temperature

Room air conditioning performance using liquid-suction heat exchanger retrofitted with R290

In this paper, a study of room air conditioning performance when using a liquid-suction heat exchanger retrofitted with R290 has been carried out with the aim of determining the influence of LSHX and R290 in terms of refrigeration effect, power consumption, COP, and heat exchanger effectiveness. A liquid-suction heat exchanger (LSHX) with length of 178 mm was designed and installed in air conditioning pipelines. The RAC used is a split-type with input power of 395 W and initial refrigerant R22. The experiment was conducted on two system conditions with 6 tests each. The results showed that LSHX provides an advantage in improving the energy efficiency of the standard RAC systems. Energy savings and increased COP can be as much as 27.69% and 38.29%. The adoption of R290 also helps reduce the potential of ozone depletion and global warming. It can be concluded that the combination of LSHX and R290 can produce better performance.

Theoretical investigation on performance improvement of a low-temperature transcritical carbon dioxide compression refrigeration system by means of an absorption chiller after-cooler

A Transcritical Carbon dioxide Compression (TCC) refrigeration system is a suitable tool to provide low-temperature refrigeration, but with a low COP. To improve the performance of a TCC, different combinations of Liquid Suction Heat Exchanger (LSHE), after-cooler and two-stage compression are embedded into the system configuration. The cooling load of the after-cooler is provided by an Absorption Chiller (ABSC) and the required heating energy to run the ABSC is recovered from the hot refrigerant leaving the compressors of the TCC. Eleven modified configurations are proposed and modeled in detail by EES software and energy and exergy analyzes are performed for each configuration. The results showed that the two-stage compression is a suitable method to upgrade the TCC system performance from both first and second laws of thermodynamics view point. The COP of a typical two-stage TCC is calculated to be 207% higher than its single-stage counterpart, in an evaporator temperature of −50 °C. It is also concluded that the combination of a two-stage compression TCC and a single-effect LiBr ABSC, performs with the highest performance. This combination increases the TCC system performances for about 4 and 2 times compared to single-stage and two-stage TCCs, respectively. A parametric study also revealed that well-calculated operating conditions are fundamental in design of TCCs to gain the highest performance.

Theoretical analysis of a Low GWP Refrigerants as a Drop in substitute of R134a in a Domestic Refrigerator

Now a days Fridges and Air-conditioners are mostly used in domestic environment. The CFCs have been almost ruled out since 1995 due to their huge impact on the ozone layer, due to the above problem HFC refrigerants are introduced but these are having a high GWP value, which causes environmental pollution. But later Kyoto protocol came into existence which stated the need to replace HFC’S due to their high GWP values. Along with the prevention of environmental pollution, performance improvement also very important. Performance of a conventional refrigeration system can be improved with the help of liquid-suction heat exchanger. So in this paper, Thermodynamic analysis of domestic refrigerator with liquid suction heat exchanger using R134a as a refrigerant was done and the results are compared with various low gwp refrigerants like, HFC152a, HC290, HC600a, HFO1234yf and HFO1234ze(E) as a possible alternative to 134a without any modification to the system. Performance parameters like COP, Refrigeration Effect, Compressor Work and Pressure ratio have been reported at various operating parameters like evaporator temperature, condenser temperature. Theoretical results revealed that all the low GWP refrigerants used in the analysis have a slightly lower performance the R134a at various condenser and evaporator temperatures

Effect degree of temperature subcooling in the performance of refrigeration with CFC, HFC and hydrocarbons refrigerant

Global warming is the result of the use of Chloro Fluoro Carbon (CFC) and Hydro Flouro Carbon (HFC) refrigerants. CFC and HFC refrigerants are not environmentally friendly in air conditioning systems. Researchers conducting the research to find an alternative refrigerant with hydrocarbon and the use of liquid suction heat exchanger (LSHX) subcooling in the vapor compression refrigeration system. One kind of LSHX is heat exchanger between tube to tube. Retrofit refrigerant is used to find a replacement refrigerant for R22, R134a, R404A with R600, and mixture refrigerant R290/R600a in the ratio 50:50. From the analysis are conclude that the increases of degree of subcooling temperature significantly affects to the effectiveness of LSHX, increase the refrigeration capacity and also refrigeration capacity index, increase the compressor of work, compressor work of index, COP and COP index. The parameters of the indicators that mixture the refrigerant R290/R600a in the ratio of 50:50 can be used as a substitution for R404A and R22, while the R600 refrigerant can be used as a substitution for R134a in the vapor compression refrigeration system with LSHX.

Experimental Evaluation of an Automobile Air - Conditioning System with and without Liquid Suction Heat Exchanger

Experimental Evaluation of an Automobile Air - Conditioning System with and without Liquid Suction Heat Exchanger

Energy Savings on Automotive Air Conditioner Using Liquid-Suction Heat Exchanger Subcooler

The present study describes a numerical analysis of the effect of subcooling using liquid-suction heat exchanger (LSHX) on the performance of automotive air conditioner. Besides increasing the cooling capacity, subcooling using LSHX also generates superheating in the suction of the compressor, where the superheating ensures only vapor phase of refrigerant entering the compressor suction and reduces the risk of damage to the compressor. The results show that the refrigeration capacity improvements and COP improvements up to 11.86% and 5.64%, respectively, for the subcooling of 1 K to 10 K and the condenser temperature of 40°C to 50°C.

Experimental Study of an Internal Heat Exchanger Influence on R134a Automobile Air Conditioning System

Liquid-suction or internal heat exchanger (IHX) is installed in vapor compression refrigeration systems to exchange energy between cool low-pressure gas and warm high-pressure liquid refrigerant. The aim of this research is to experimentally evaluate the effect of IHX adaptation in an automotive air conditioning system focusing on evaporator working conditions. In this new design of IHX, the high-pressure liquid passes through the central channel and the low-pressure vapor flows in several parallel channels in the opposite direction. The experimental set-up has been made up of original components of the air conditioning system of a medium sedan car, specially designed and built to analyze vehicle A/C equipments under real work conditions. The results show that low pressure drop will be imposed on the cycle using this type of IHX. Also, they confirm considerable decrease of compressor power consumption; it is intensified at higher evaporator air flow. A significant improvement of the coefficient of performance will be achieved with IHX too. The influence of operating conditions has been also discussed in this paper.

Refrigeration system performance using liquid-suction heat exchangers

Heat transfer devices are provided in many refrigeration systems to exchange energy between the cool gaseous refrigerant leaving the evaporator and warm liquid refrigerant exiting the condenser. These liquid-suction or suction-line heat exchangers can, in some cases, yield improved system performance while in other cases they degrade system performance. Although previous researchers have investigated performance of liquid-suction heat exchangers, this study can be distinguished from the previous studies in three ways. First, this paper identifies a new dimensionless group to correlate performance impacts attributable to liquid-suction heat exchangers. Second, the paper extends previous analyses to include new refrigerants. Third, the analysis includes the impact of pressure drops through the liquid-suction heat exchanger on system performance. It is shown that reliance on simplified analysis techniques can lead to inaccurate conclusions regarding the impact of liquid-suction heat exchangers on refrigeration system performance. From detailed analyses, it can be concluded that liquid-suction heat exchangers that have a minimal pressure loss on the low pressure side are useful for systems using R507A, R134a, R12, R404A, R290, R407C, R600, and R410A. The liquid-suction heat exchanger is detrimental to system performance in systems using R22, R32, and R717.