scholarly journals Measurement Method and Experimental Analysis of Liquid Entrainment for a Flooded Evaporator of a Water-Cooled Centrifugal Chiller Based on Energy Balance

2021 ◽  
Vol 11 (17) ◽  
pp. 8165
Author(s):  
Xinghua Huang ◽  
Yunqian Zhang ◽  
Zuqiang Li ◽  
Yaolin Lin
Keyword(s):  
Energy Balance ◽  
Uncertainty Propagation ◽  
Cooling Capacity ◽  
Input Power ◽  
Exchange Capacity ◽  
Experimental Results ◽  
Coefficient Of Performance ◽  
Efficient Operation ◽  
Liquid Entrainment ◽  
Centrifugal Chiller

Liquid entrainment in a flooded evaporator has an important impact on the performance and safety of a water-cooled centrifugal chiller. In this paper, two methods for measuring the liquid entrainment factor in the evaporator of a centrifugal chiller based on energy balance are proposed. Method 1 involves only the heat exchange capacity of the evaporator and Method 2 involves both evaporator and condenser. The applicable conditions of the methods are discussed. Experimental measurements on the flooded evaporator of a single-stage water-cooled centrifugal chiller with refrigerant R134a show that, for a system with good thermal balance, there is little difference in the entrainment factor values obtained by the two methods. Method 2 was found to have slightly higher measurement accuracy, compared to Method 1. The uncertainty propagation analysis shows that for method two, the inlet and outlet water temperatures of the evaporator and condenser, motor input power, motor efficiency, transmission power loss and compressor suction and discharge temperatures are important factors. The experimental results show that the variation of the evaporator entrainment factor with refrigerant charge amount is different for different cooling capacity. At 700 and 800 refrigeration ton (RT), the entrainment factor of the test evaporator increases with the increase of refrigerant charge and the growth rate gradually accelerates. For the chiller tested, when the entrainment factor reaches 0.89% and 1.02%, respectively, at 700 ton and 800 ton, the rapid increase of the entrainment factor leads to a significant decrease in the coefficient of performance (COP) during the charging process. Based on the analysis of the experimental results, it is recommended that the maximum entrainment factor for efficient operation of the centrifugal chiller should be controlled within 1%.

scholarly journals An IoT-Based Thermoelectric Air Management Framework for Smart Building Applications: A Case Study for Tropical Climate

2020 ◽  
Vol 12 (4) ◽  
pp. 1564
Author(s):  
Kashif Irshad ◽  
Abdulmohsen Almalawi ◽  
Asif Irshad Khan ◽  
Md Mottahir Alam ◽  
Md. Hasan Zahir ◽  
...  
Keyword(s):  
Cooling Capacity ◽  
Input Power ◽  
Climatic Conditions ◽  
Coefficient Of Performance ◽  
Air Cooling ◽  
Thermoelectric Coolers ◽  
Air Conditioners ◽  
Management Framework ◽  
Smart Building ◽  
Thermal Management System

This study investigates the performance of the thermoelectric air conditioning (TE-AC) system smartly controlled by the Internet of Things (IoT)-based configuration for real tropical climatic application. Air cooling management was done through thermoelectric coolers, and an Arduino microcontroller with various sensors such as a temperature sensor, simple RF modules, and actuators was used to control the indoor climatic conditions based on outdoor conditions. The result shows that when the input power supply to the IoT-based TE-AC system is increased, the cooling capacity of the framework is also enhanced. Significant power and carbon emission reduction was observed for the IoT-based TE-AC system as compared to the TE-AC system without IoT. The IoT-incorporated system also ensures better microclimatic temperature control. Additionally, the system cooling capacity improves by 14.0%, and the coefficient of performance is increased by 46.3%. Thus, this study provides a smart solution to the two major energy harvesting issues of traditional air conditioners—an increase in energy efficiency by employing a TE-AC system and a further improvement in efficiency by using an IoT-based thermal management system.

scholarly journals EFFECT OF AIR FLOW OBSTRUCTION IN A CONDENSING UNIT ON SPLIT AIR CONDITIONER PERFORMANCE

2020 ◽  
Vol 82 (5) ◽  
Author(s):  
Andriyanto Setyawan
Keyword(s):  
Air Conditioning ◽  
Air Flow ◽  
Cooling Capacity ◽  
Input Power ◽  
The Other ◽  
Coefficient Of Performance ◽  
Air Conditioner ◽  
Air Conditioning System ◽  
Heat Rejection ◽  
Other Hand

Obstructions of air flow in the outdoor unit could block the condenser air flow and reduce its heat rejection As a result, it could decrease the performance of a room air conditioning system. The paper presents the effects of the air flow obstruction of a condensing unit on the performance of a split-type air conditioner with refrigerant R410A. The study was conducted experimentally by employing front and side obstructions with varied distance from the condensing unit. The front obstruction of 100 cm height was applied at varied distance from 10 cm to 100 cm, while the side obstruction of the same height was applied at distance of 5, 10, and 15 cm. The presence of air flow obstructions results in the decrease of cooling capacity and coefficient of performance (COP). On the other hand, it increases the input power of the AC unit. From the experiment, it is obvious that the distance of front obstruction of 10 cm results in the reduction of cooling capacity by 46% and COP by 56%. It is also revealed that the distance of the front obstruction of 50 cm or more has no significant effect for the performance of the air conditioning unit. In addition, the side obstructions have the less significant effect than that of the front obstruction.

Design and Experimental Investigation of a Diffusion Absorption Refrigeration System

2006 ◽  
Author(s):  
Shiming Xu ◽  
Jian Liang ◽  
Yi Jian He ◽  
Ru Xu Du
Keyword(s):  
Cooling Capacity ◽  
Input Power ◽  
Experimental Results ◽  
Working Fluid ◽  
Absorption Refrigeration ◽  
Operation Condition ◽  
Operation Conditions ◽  
System Pressure ◽  
Diffusion Absorption ◽  
Bubble Pump

This paper presents the design and experimental analysis of a compact Diffusion Absorption Air Cooler (DAAC) system, in which the Diffusion Absorption Refrigeration (DAR) technology is utilized. The system uses a bubble pump to replace the mechanical pump, uses three-component working fluid (NH3+H2O+He), and operates under the same system pressure level. Hence, it is quiet, long lasting and environmental friendly. To investigate the practicality of using the DAAC system for regional air conditioning, the thermodynamic model is derived to guide the system design first, and then a DAAC experimental prototype is built for validation. Since the bubble pump is the kernel component, a series of experiments are conducted to investigate the bubble pump performance. From the experimental results under various operation conditions, it is found that the bubble pump dominates the system performance and should be designed carefully to match the designed cooling capacity and operation condition. The experimental results also show that the DAAC can work smoothly under various ambient temperatures when the input power of bubble pump is over 200W.

Thermodynamic analysis of triple effect ammonia–water absorption compression (hybrid) cycle

2021 ◽  
pp. 095440892199568
Author(s):  
CP Jawahar
Keyword(s):  
Water Absorption ◽  
Energy Analysis ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Performance Parameters ◽  
Evaporator Temperature ◽  
Ammonia Water ◽  
Absorption Cycle ◽  
Hybrid Cycle

This paper presents the energy analysis of a triple effect absorption compression (hybrid) cycle employing ammonia water as working fluid. The performance parameters such as cooling capacity and coefficient of performance of the hybrid cycle is analyzed by varying the temperature of evaporator from −10 °C to 10 °C, absorber and condenser temperatures in first stage from 25 °C to 45 °C, degassing width in both the stages from 0.02 to 0.12 and is compared with the conventional triple effect absorption cycle. The results of the analysis show that the maximum cooling capacity attained in the hybrid cycle is 472.3 kW, at 10 °C evaporator temperature and first stage degassing width of 0.12. The coefficient of performance of the hybrid cycle is about 30 to 65% more than the coefficient of performance of conventional triple effect cycle.

THE EFFECT OF LIQUID SUCTION HEAT EXCHANGER SUB-COOLER ON PERFORMANCE OF A FREEZER USING R404A AS WORKING FLUID

2015 ◽  
Vol 76 (11) ◽  
Author(s):  
Muhammad Nuriyadi ◽  
Sumeru Sumeru ◽  
Henry Nasution
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Cooling Capacity ◽  
Experimental Results ◽  
Working Fluid ◽  
Liquid Line ◽  
Cabin Temperature

This study presents the effect of liquid-suction heat exchangers (LSHX) sub-cooler in a freezer. The LSHX sub-cooler is a method to increase the cooling capacity of the evaporator by lowering temperature at the condenser outlet. The decrease in temperature of the condenser outlet will cause a decrease in the quality refrigerant entering the evaporator. The lower the quality of the refrigerant entering the evaporator, the higher the cooling capacity produced by the evaporator. The LSHX sub-cooler utilizes a heat exchanger to transfer heat from the outlet of the condenser (liquid line) to the suction of the compressor. In the present study, three different LSHX sub-coolers in the freezer with cabin temperature settings of 0, -10 and -20oC were investigated. The results showed that the lowest and the highest of effectiveness of the heat exchanger were 0.28 and 0.58, respectively. The experimental results also showed that EER reduction is occurred at the cabin temperature setting of 0oC and -10oC, whereas the EER improvements were always occurred at the cabin temperature settings of -20oC.

scholarly journals KAJI PERFORMANSI REFRIGERAN R-290, R-32, DAN R-410A SEBAGAI ALTERNATIF PENGGANTI R-22

2021 ◽  
Vol 4 ◽  
pp. 133-139
Author(s):  
Rikhard Ufie ◽  
Cendy S. Tupamahu ◽  
Sefnath J. E. Sarwuna ◽  
Jufraet Frans
Keyword(s):  
Air Conditioning ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Condensation Temperature ◽  
Vapor Compression ◽  
Know How ◽  
Evaporation Temperature ◽  
Vapor Compression Cycle ◽  
Compression Cycle ◽  
Refrigeration Capacity

Refrigerant R-22 is a substance that destroys the ozone layer, so that in the field of air conditioning it has begun to be replaced, among others with refrigerants R-32 and R-410a, and also R-290. Through this research, we want to know how much Coefficient of Performance (COP) and Refrigeration Capacity (Qe) can be produced for the four types of refrigerants. The study was carried out theoretically for the working conditions of the vapor compression cycle with an evaporation temperature (Tevap) of 0, -5, and -10oC, a further heated refrigerant temperature (ΔTSH) of 5 oC, a condensation temperature (Tkond) of 45 oC and a low-cold refrigerant temperature. (ΔTSC) 10 oC and compression power of 1 PK . The results of the study show that the Coefficient of Performance (COP) in the use of R-22 and R-290 is higher than the use of R-32 and R-410a, which are 4,920 respectively; 4,891; 4.690 and 4.409 when working at an evaporation temperature of 0 oC; 4.260; 4,234; 4.060 and 3.812 when working at an evaporation temperature of -5 oC; and amounted to 3,730; 3,685; 3,550 and 3,324 if working at an evaporation temperature of -10 oC. Based on the size of the COP, if this installation works with a compression power of 1 PK, then the cooling capacity of the R-22 and R-290 is higher than the R-32 and R-410a, which are 3,617 respectively. kW; 3,597 kW; 3,449 kW and 3,243 kW. If working at an evaporation temperature of 0 oC; 3.133 kW; 3.114 kW; 2,986 kW and 2,804 kW if working at an evaporation temperature of -5 oC; and 2,741 kW; 2,710 kW; 2,611 kW and 2,445 kW if working at an evaporation temperature of -10oC.

scholarly journals The Effect of Refrigerant Charge and Outdoor Temperature on the Condenser and Evaporator of a Split-Unit Type Air Conditioner Using R22 Refrigerant

2018 ◽  
Vol 225 ◽  
pp. 02013
Author(s):  
Mohd Hazwan Yusof ◽  
Sulaiman Mohd Muslim ◽  
Muhammad Fadhli Suhaimi ◽  
Mohamad Firdaus Basrawi
Keyword(s):  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Air Conditioner ◽  
Outdoor Temperature ◽  
Unit Type ◽  
Small Capacity

To maintain the temperature setup on an air conditioner, the compressor will use more or less energy based on the outdoor temperature. Therefore, there is a need to understand the performance of the air conditioner if the outdoor temperature is varied. In this research, a used small capacity split-unit air conditioner using R-22 refrigerant is used to study the effect of outdoor temperature on the performance of the air conditioner. From the results, it can be understood that lower outdoor temperature requires less work from the compressor. The cooling capacity and coefficient of performance drop as the outdoor temperature increases.

scholarly journals Performance Evaluation of a Gravity-Assisted Heat Pipe-Based Indirect Evaporative Cooler

Energies ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 200 ◽  
Author(s):  
Krzysztof Rajski ◽  
Jan Danielewicz ◽  
Ewa Brychcy
Keyword(s):  
Mathematical Model ◽  
Heat Pipe ◽  
Cooling Capacity ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Mass Transfer Processes ◽  
Air Cooler ◽  
Evaporative Cooler ◽  
The Mathematical Model ◽  
Further Development

In the present work, the effects of different operating parameters on the performance of a gravity-assisted heat pipe-based indirect evaporative cooler (GAHP-based IEC) were investigated. The aim of the theoretical study is to evaluate accurately the cooling performance indicators, such as the coefficient of performance (COP), wet bulb effectiveness, and cooling capacity. To predict the effectiveness of the air cooler under a variety of conditions, the comprehensive calculation method was adopted. A mathematical model was developed to simulate numerically the heat and mass transfer processes. The mathematical model was validated adequately using experimental data from the literature. Based on the conducted numerical simulations, the most favorable ranges of operating conditions for the GAHP-based IEC were established. Moreover, the conducted studies could contribute to the further development of novel evaporative cooling systems employing gravity-assisted heat pipes as efficient equipment for transferring heat.

scholarly journals Thermal Performance Analysis of Low-GWP Refrigerants in Automotive Air-Conditioning System

2020 ◽  
Vol 2020 ◽  
pp. 1-14 ◽  
Author(s):  
Yousuf Alhendal ◽  
Abdalla Gomaa ◽  
Gamal Bedair ◽  
Abdulrahim Kalendar
Keyword(s):  
Air Conditioning ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Exergy Destruction ◽  
Air Conditioning System ◽  
Capacity Coefficient ◽  
Automotive Air Conditioning ◽  
Automotive Air Conditioning System ◽  
Compressor Power ◽  
Low Global Warming Potential

The energy and exergy of low-global warming potential (GWP) refrigerants were investigated experimentally and theoretically. Refrigerants with a modest GWP100 of  ≤ 150 can be sufficient for bringing down emissions which were concerned for the automotive air-conditioning system. Three types of low-GWP refrigerants, R152a, R1234yf, and R1234ze(E), were examined with particular reference to the current high-GWP of R134a. The effect of different evaporating and condensing temperatures in addition to compressor speed was considered. The purpose was to bring a clear view of the performance characteristics of possible environment friendly alternatives of R134a. The analysis was carried out with compressor power, cooling capacity, coefficient of performance, exergy destruction, and exergy efficiency. It was noted that the total exergy destruction of R1234yf was reduced by 15% compared to that of R134a. The refrigerant R1234ze(E) has the highest energetic and exergetic performance compared with the other investigated refrigerants.

scholarly journals Installation and Operation of a Solar Cooling and Heating System Incorporated with Air-Source Heat Pumps

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 996 ◽  
Author(s):  
Li Huang ◽  
Rongyue Zheng ◽  
Udo Piontek
Keyword(s):  
Heating System ◽  
Cooling Capacity ◽  
Heat Pumps ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Energy Yield ◽  
Absorption Chiller ◽  
Annual Average ◽  
Water Storage Tank ◽  
Solar Cooling

A solar cooling and heating system incorporated with two air-source heat pumps was installed in Ningbo City, China and has been operating since 2018. It is composed of 40 evacuated tube modules with a total aperture area of 120 m2, a single-stage and LiBr–water-based absorption chiller with a cooling capacity of 35 kW, a cooling tower, a hot water storage tank, a buffer tank, and two air-source heat pumps, each with a rated cooling capacity of 23.8 kW and heating capacity of 33 kW as the auxiliary system. This paper presents the operational results and performance evaluation of the system during the summer cooling and winter heatingperiod, as well as on a typical summer day in 2018. It was found that the collector field yield and cooling energy yield increased by more than 40% when the solar cooling and heating system is incorporated with heat pumps. The annual average collector efficiency was 44% for cooling and 42% for heating, and the average coefficient of performance (COP) of the absorption chiller ranged between 0.68 and 0.76. The annual average solar fraction reached 56.6% for cooling and 62.5% for heating respectively. The yearly electricity savings accounted for 41.1% of the total electricity consumption for building cooling and heating.

Sign in / Sign up

Export Citation Format

Share Document