scholarly journals The effect of the chilled water temperature on the performance of an experimental air-cooled chiller

2021 ◽  
Author(s):  
Phan Thi Thu Huong ◽  
Hoang Mai Hong ◽  
Lai Ngoc Anh
Keyword(s):  
Water Temperature ◽  
Coefficient Of Performance ◽  
Condensation Temperature ◽  
Measured Temperature ◽  
Isentropic Compression ◽  
Compression Efficiency ◽  
Evaporation Temperature ◽  
Study Results ◽  
Chilled Water ◽  
Temperature And Pressure

This paper presents the study results on the effect of the chilled water temperature on the coefficient of performance (COP) of an experimental air-cooled chiller. The measuring sensors and instrument were calibrated, and the uncertainty of the measuring temperature and pressure were evaluated. The uncertainty of measured temperature and pressure at 95% confidence level is 0.12 °C and 1.4 kPa, respectively. The isentropic compression efficiency and the COP of the air-cooled chiller operating at a condensation temperature of 48.05 °C and evaporation temperature of 3.17 °C are 63% and 2.69, respectively. The chilled water temperature has a significant influence on evaporation pressure and the COP of the chiller. If the temperature of the air entering the condenser of the chiller is maintained at 35 °C, the COP of the chiller increases from 2.55 to 2.89 when the temperature of the chiller water increases only 4 K, from 8 °C to 12 °C.

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.

Performance Evaluation of Modified Low-Temperature Cascade (MLTC) Type Refrigeration System

2021 ◽  
pp. 2150023
Author(s):  
Mohd Waseem Siddiqui ◽  
Nishith Kumar Das ◽  
R. K. Sahoo
Keyword(s):  
Performance Evaluation ◽  
Low Temperature ◽  
Cooling Tower ◽  
Coefficient Of Performance ◽  
Slight Variation ◽  
Refrigeration System ◽  
Isentropic Compression ◽  
Compression Efficiency ◽  
Normal Water ◽  
Cascade Type

An experimental investigation was carried out to study the performance evaluation of Modified Low-Temperature Cascade (MLTC) system, based on two-stage cascade type refrigeration system using the combination of R404A/R23 refrigerants. This system was developed using chilled water (CHW) in the condenser of high-temperature circuit (HTC) and pre-cooler (PC) in the low-temperature circuit (LTC). Isentropic compression efficiency is computed in this work and used here as an important parameter. Performance of MLTC system was compared with or without the introduction of PC into LTC. System’s coefficient of performance (COP) has also been compared with using CHW, cooling tower water (CTW), normal water (NW) into the HTC condenser. It has also been shown that COPs of the system are significantly affected by slight variation in the LTC and HTC evaporating temperatures. Presented parameters and comparisons are likely to help in developing a low-temperature (LT) refrigeration system with higher efficiency for industrial and other applications.

A Dynamic Model of a Single-Stage LiBr-H2O Absorption Chiller

2016 ◽  
Author(s):  
Prangtip Samutr ◽  
Ali Al Alili
Keyword(s):  
Water Temperature ◽  
Dynamic Model ◽  
Cooling Capacity ◽  
Hot Water ◽  
Single Stage ◽  
Coefficient Of Performance ◽  
Maximum Relative Error ◽  
Outlet Temperature ◽  
Absorption Chiller ◽  
Chilled Water

This paper presents a dynamic model of a single-stage LiBr-H2O absorption chiller. A numerical model has been developed based on mass and energy balance equations and heat transfer equations. The model is developed using MATLAB program and the system of non-linear ordinary differential equation is solved using the 4th-order Runge-Kutta method. The model is validated with experimental results from pertained literature. The results show that the maximum relative error is found when comparing the dynamic model predicted chilled water outlet temperature to experimental data, which is around 9%. The effect of the inlet hot water temperature on the hot, cooling and chilled water outlet temperatures, cooling capacity and coefficient of performance (COP) are also studied. The results show that as the hot water outlet temperature increases, the outlet temperatures of cooling and chilled water slightly change. Moreover, the cooling capacity increases and the COP slight decreases as the hot water temperature increases.

scholarly journals Performance Evaluation of an Adsorption Heat Pump System Using MSC-30/R1234yf Pair with the Impact of Thermal Masses

2021 ◽  
Vol 11 (5) ◽  
pp. 2279
Author(s):  
Sangwon Seo ◽  
František Mikšík ◽  
Yuta Maeshiro ◽  
Kyaw Thu ◽  
Takahiko Miyazaki
Keyword(s):  
Heat Pump ◽  
Adsorption Isotherms ◽  
Coefficient Of Performance ◽  
Variable Pressure ◽  
Condensation Temperature ◽  
Relative Pressure ◽  
Pump System ◽  
Adsorption Heat Pump ◽  
Adsorbed Phase ◽  
The Impact

In this study, we evaluated the performance of low Global Warming Potential (GWP) refrigerant R1234yf on the activated carbon (MSC-30) for adsorption heating applications. The adsorption isotherms of MSC-30/R1234yf were measured using a constant-volume–variable-pressure (CVVP) method from very low relative pressure to the practical operating ranges. The data were fitted with several isotherm models using non-linear curve fitting. An improved equilibrium model was employed to investigate the influence of dead thermal masses, i.e., the heat exchanger assembly and the non-adsorbing part of the adsorbent. The model employed the model for the isosteric heat of adsorption where the adsorbed phase volume was accounted for. The performance of the heat pump was compared with MSC-30/R134a pair using the data from the literature. The analysis covered the desorption temperature ranging from 60 °C to 90 °C, with the evaporation temperature at 5 °C and the adsorption temperature and condensation temperature set to 30 °C. It was observed that the adsorption isotherms of R1234yf on MSC-30 were relatively lower than those of R134a by approximately 12%. The coefficient of performance (COP) of the selected pair was found to vary from 0.03 to 0.35 depending on the heat source temperature. We demonstrated that due to lower latent heat, MSC-30/R1234yf pair exhibits slightly lower cycle performance compared to the MSC-30/R134a pair. However, the widespread adaptation of environmentally friendly R1234yf in automobile heat pump systems may call for the implementation of adsorption systems such as the direct hybridization using a single refrigerant. The isotherm and performance data presented in this work will be essential for such applications.

scholarly journals A Multi-Iteration Enhanced 2P-SMA Method for Improved Error Reduction on a WP-SAW Water Temperature and Pressure Sensor

IEEE Access ◽  
2021 ◽  
Vol 9 ◽  
pp. 48236-48243
Author(s):  
Zhaozhao Tang ◽  
Wenyan Wu ◽  
Jinliang Gao ◽  
Jingting Luo ◽  
Ran Tao ◽  
...  
Keyword(s):  
Water Temperature ◽  
Pressure Sensor ◽  
Error Reduction ◽  
Temperature And Pressure

scholarly journals The measured temperature and pressure of EDC37 detonation products

2017 ◽  
Author(s):  
J. W. Ferguson ◽  
J. C. Richley ◽  
B. D. Sutton ◽  
E. Price ◽  
T. A. Ota
Keyword(s):  
Measured Temperature ◽  
Detonation Products ◽  
Temperature And Pressure

Measured temperature and pressure dependence of Vp and Vs in compacted, polycrystalline sI methane and sII methane–ethane hydrate

2003 ◽  
Vol 81 (1-2) ◽  
pp. 47-53 ◽  
Author(s):  
M B Helgerud ◽  
W F Waite ◽  
S H Kirby ◽  
A Nur
Keyword(s):  
High Pressure ◽  
Shear Wave ◽  
Pressure Dependence ◽  
Gas Hydrate ◽  
Pressure Vessel ◽  
Wave Speed ◽  
Measured Temperature ◽  
Shear Wave Speed ◽  
Temperature And Pressure ◽  
Fixed End

We report on compressional- and shear-wave-speed measurements made on compacted polycrystalline sI methane and sII methane–ethane hydrate. The gas hydrate samples are synthesized directly in the measurement apparatus by warming granulated ice to 17°C in the presence of a clathrate-forming gas at high pressure (methane for sI, 90.2% methane, 9.8% ethane for sII). Porosity is eliminated after hydrate synthesis by compacting the sample in the synthesis pressure vessel between a hydraulic ram and a fixed end-plug, both containing shear-wave transducers. Wave-speed measurements are made between –20 and 15°C and 0 to 105 MPa applied piston pressure. PACS No.: 61.60Lj

scholarly journals Efficiency Evaluation of the Ejector Cooling Cycle using a New Generation of HFO/HCFO Refrigerant as a R134a Replacement

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2136 ◽  
Author(s):  
Bartosz Gil ◽  
Jacek Kasperski
Keyword(s):  
High Efficiency ◽  
Coefficient Of Performance ◽  
Condensation Temperature ◽  
Evaporation And Condensation ◽  
Wide Range ◽  
Theoretical Investigations ◽  
Maximum Coefficient ◽  
C 30 ◽  
New Generation ◽  
And Control

Theoretical investigations of the ejector refrigeration system using hydrofluoroolefins (HFOs) and hydrochlorofluoroolefin (HCFO) refrigerants are presented and discussed. A comparative study for eight olefins and R134a as the reference fluid was made on the basis of a one-dimensional model. To facilitate and extend the possibility of comparing our results, three different levels of evaporation and condensation temperature were adopted. The generator temperature for each refrigerant was changed in the range from 60 °C to the critical temperature for a given substance. The performed analysis shown that hydrofluoroolefins obtain a high efficiency of the ejector system at low primary vapor temperatures. For the three analyzed sets of evaporation and condensation temperatures (te and tc equal to 0 °C/25 °C, 6 °C/30 °C, and 9 °C/40 °C) the maximum Coefficient of Performance (COP) was 0.35, 0.365, and 0.22, respectively. The best performance was received for HFO-1243zf and HFO-1234ze(E). However, they do not allow operation in a wide range of generator temperatures, and, therefore, it is necessary to correctly select and control the operating parameters of the ejector.

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