scholarly journals Experimental investigation of a novel metal-organic framework (MOF) based humidity pump under high humidity conditions

2021 ◽  
Vol 2069 (1) ◽  
pp. 012049
Author(s):  
Kan Zu ◽  
Menghao Qin
Keyword(s):  
Moisture Transfer ◽  
Metal Organic Framework ◽  
Significant Proportion ◽  
Coefficient Of Performance ◽  
High Humidity ◽  
Moisture Removal ◽  
Vapor Compression ◽  
Metal Organic ◽  
Low Humidity ◽  
Vapor Compression Refrigeration

Abstract Latent heat load accounts for a significant proportion of air-conditioning energy consumption and particularly for specific environment in humid climates. Traditional vapor-compression refrigeration dehumidification faces the problem of refrigerant leakage, overcooling and complicated mechanical systems. Here, we report a novel humidity pump that uses semiconductor refrigeration and metal-organic frameworks (MOFs) as dehumidification method, which can efficiently transport moisture from a relatively ‘low-humidity’ space to a high-humidity one. The working principles of the humidity pump were introduced that the process air flows through the cold desiccant coated heat exchanger and then comes into direct contact with the MOF coatings to transfer heat and mass. The dehumidification performance of humidity pump was investigated in high humidity, and the dehumidification coefficient of performance (DCOP), dehumidification rate and moisture removal efficiency using MIL-100(Fe) coatings were calculated. The results indicated that the MOF humidity pump possesses excellent moisture transfer ability.

An Experimental Investigation on Vapor Compression Refrigeration System Cascaded with Ejector Refrigeration System

2021 ◽  
pp. 2150028
Author(s):  
Vikas Kumar ◽  
Gulshan Sachdeva ◽  
Sandeep Tiwari ◽  
Parinam Anuradha ◽  
Vaibhav Jain
Keyword(s):  
Experimental Investigation ◽  
Thermal Equilibrium ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Compression System ◽  
Vapor Compression System ◽  
Vapor Compression Refrigeration ◽  
Cascaded System

A conventional vapor compression refrigeration system (VCRS) cascaded with a heat-assisted ejector refrigeration system (ERS) has been experimentally analyzed. Cascading allows the VCRS to operate at lower condenser temperatures and thus achieve a higher coefficient of performance. In this cascaded system, the condenser of the vapor compression system does not dissipate its heat directly to the evaporator of the ERS; instead, water circulates between the condenser of VCRS and the evaporator of ERS to exchange the heat. Seven ejectors of different geometries have been used in the ERS; however, all the ejectors could not maintain thermal equilibrium at the desired operating conditions. The compressor of the cascaded VCRS consumed 1.3 times less power than the noncascaded VCRS. Furthermore, the cascaded system provided a maximum 87.74% improvement in COP over the noncascaded system for the same operating conditions. The performance of the system remained constant until the critical condenser pressure of the ERS.

Refrigeration Cooled Computers: Application and Review

2000 ◽  
Author(s):  
R. R. Schmidt ◽  
M. J. Ellsworth ◽  
R. C. Chu ◽  
D. Agonafer
Keyword(s):  
Temperature Stability ◽  
Continuous Operation ◽  
Coefficient Of Performance ◽  
System Level ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Maintenance System ◽  
Vapor Compression Refrigeration ◽  
Computer Processor ◽  
Heat Loads

Abstract This paper outlines and discusses the application conditions pertinent to refrigeration cooling a computer processor at both the module and system level. Amongst the issues that are addressed are total refrigeration heat load (comprised of active and parasitic heat loads), coefficient of performance (COP), continuous operation (reliability, concurrent maintenance), system heat rejection, condensation formation, and temperature stability. The paper will then examine how a vapor compression refrigeration system has been incorporated in IBM’s high end (Gx) servers. Finally, the paper will touch upon some of the additional complexities of operation at very low temperatures (less than −40 °C).

scholarly journals Parametric analysis of a combined ejector-vapor compression refrigeration cycle

2020 ◽  
Vol 15 (3) ◽  
pp. 398-408
Author(s):  
I Ouelhazi ◽  
Y Ezzaalouni ◽  
L Kairouani
Keyword(s):  
Current Model ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Refrigeration Cycle ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Entrainment Ratio ◽  
Constant Area ◽  
Vapor Compression Refrigeration Cycle ◽  
Vapor Compression Refrigeration

Abstract From the last few years, the use of efficient ejector in refrigeration systems has been paid a lot of attention. In this article a description of a refrigeration system that combines a basic vapor compression refrigeration cycle with an ejector cooling cycle is presented. A one-dimensional mathematical model is developed using the flow governing thermodynamic equations based on a constant area ejector flow model. The model includes effects of friction at the constant-area mixing chamber. The current model is based on the NIST-REFPROP database for refrigerant property calculations. The model has basically been used to determine the effect of the ejector geometry and operating conditions on the performance of the whole refrigeration system. The results show that the proposed model predicts ejector performance, entrainment ratio and the coefficient of performance of the system and their sensitivity to evaporating and generating temperature of the cascade refrigeration cycle. The simulated performance has been then compared with the available experimental data from the literature for validation.

scholarly journals THEORETICAL AND EXPERIMENTAL ANALYSIS OF A VAPOR-COMPRESSION REFRIGERATION CYCLE WITH A HEAT EXCHANGER BETWEEN THE SUCTION AND LIQUID LINES

2019 ◽  
Vol 18 (2) ◽  
pp. 19
Author(s):  
L. S. Santana ◽  
J. Castro ◽  
L. M. Pereira
Keyword(s):  
Heat Exchanger ◽  
Experimental Analysis ◽  
Thermodynamic Cycle ◽  
Electrical Energy ◽  
Coefficient Of Performance ◽  
Refrigeration Cycle ◽  
Vapor Compression ◽  
Vapor Compression Refrigeration Cycle ◽  
Vapor Compression Refrigeration ◽  
Liquid Heat

Vapor-compression refrigeration systems require a significant amount of electrical energy. Therefore, there is a need for finding efficient ways of operating this equipment, reducing their energy consumption. The use of heat exchangers between the suction line and the liquid line can produce a better performance of the thermodynamic cycle, as well as reduce it. The present work aims at an experimental analysis of the suction/liquid heat exchanger present in a freezer running with refrigerant fluid R-134a. Three different scenarios were used in order to evaluate the thermal performance of the refrigeration cycle. The first scenario was the conventional freezer set up to collect the required data for further comparison. Moreover, the second and third scenarios were introduced with a 20 cm and 40 cm suction/liquid heat exchanger, respectively, into the system. From the experiments, it was observed that the heat exchange does not significantly affect the coefficient of performance (COP) of the freezer. It was concluded from this work that the best scenario analyzed was the 20 cm suction/liquid heat exchanger where most of the thermodynamic properties were improved, one of them being the isentropic efficiency.

scholarly journals Energy Analysis of Vapor Compression Refrigeration Cycle Using a New Generation Refrigerants with Low Global Warming Potential

2021 ◽  
Vol 87 (2) ◽  
pp. 106-117
Author(s):  
Rabah Touaibi ◽  
Hasan Koten
Keyword(s):  
Global Warming ◽  
Global Warming Potential ◽  
Energy Analysis ◽  
Coefficient Of Performance ◽  
Cycle Performance ◽  
Refrigeration Cycle ◽  
Vapor Compression ◽  
Vapor Compression Refrigeration Cycle ◽  
Vapor Compression Refrigeration ◽  
Low Global Warming Potential

An energy analysis study carried out on a vapor compression refrigeration cycle using refrigerants with low global warming potential (GWP) of the Hydro-Fluoro-Olefin (HFO) type, in particular R1234yf and R1234ze fluids to replace HFC refrigerants . Computer code was developed using software for solving engineering equations to calculate performance parameters; for this, three HFC type fluids (R134a, R404A and R410A) were selected for a comparative study. The results showed that R1234ze is the best refrigerant among those selected for the mechanical vapor compression refrigeration cycle. The thermodynamic analysis showed the effect of the evaporator temperature (-22 °C to 10 °C) and the condenser temperature (30 °C to 50 °C) on the steam cycle performance. Compression refrigeration, including the coefficient of performance. The results showed that the HFO-R1234ze with low GWP gives the best coefficient of performance of 3.14 close to that of the R134a fluid (3.17). In addition, R1234ze is considered an alternative fluid to R134a for their ecological properties.

Properties and Performance of Eco-Friendly Hydro-Fluoro-Olefin (HFO) Refrigerant-R1234yf: Part I

2021 ◽  
pp. 2130005
Author(s):  
B. S. Bibin ◽  
Edison Gundabattini
Keyword(s):  
Ozone Depletion ◽  
Past Research ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
General Effect ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Vapor Compression Refrigeration ◽  
Principal Points ◽  
And Performance

The creation of new age refrigerants might be the answer to the issue of an Earth-wide rise in temperature. Hence, while choosing new refrigerants a careful process is required. The general effect of any refrigerant substance on global warming, energy efficiency, ozone depletion, cost-effectiveness, chemical stability, and safety ought to be assessed. This paper sums up the experimental and numerical investigations directed with the globally accepted R1234yf refrigerant. The paper’s principal points are to assess the capability of the hydro-fluoro-olefin (HFO) refrigerant mainly R1234yf utilized in the refrigeration system (vapor compression systems, domestic refrigeration system) and to explore its utilization as an eco-friendly refrigerant. In the vapor compression refrigeration system, the cooling capacity and coefficient of performance of R1234yf are found to be less, 9% and 11%, respectively compared to that of R134a. But the power consumption of the system with R1234yf increased between 1.6% and 6.7% when compared to R134a. This paper likewise assists with recognizing the gap in the past research works and explores the possibilities for additional works.

Metal–organic framework–graphene oxide composites: a facile method to highly improve the proton conductivity of PEMs operated under low humidity

2015 ◽  
Vol 3 (31) ◽  
pp. 15838-15842 ◽  
Author(s):  
Lijia Yang ◽  
Beibei Tang ◽  
Peiyi Wu
Keyword(s):  
Graphene Oxide ◽  
Proton Conductivity ◽  
Metal Organic Framework ◽  
Proton Exchange Membranes ◽  
Proton Exchange ◽  
Oxide Composite ◽  
Metal Organic ◽  
Low Humidity ◽  
Oxide Composites ◽  
Organic Framework

Nafion based proton exchange membranes (PEMs) modified by a metal–organic framework–graphene oxide composite (ZIF-8@GO) are reported.

Experimental evidence concerning the different behavior of energy and exergy performance indicators of refrigeration systems in transient regimes

2016 ◽  
Vol 41 (1) ◽  
Author(s):  
Elena Eugenia Vasilescu ◽  
Michel Feidt ◽  
Rahal Boussehain ◽  
Alexandru Dobrovicescu
Keyword(s):  
Exergy Analysis ◽  
Initial Temperature ◽  
Stationary Regime ◽  
Coefficient Of Performance ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Transient Regimes ◽  
Energy And Exergy ◽  
Vapor Compression Refrigeration ◽  
Exergy Performance

AbstractThis article presents the results obtained from an energy-exergy analysis of a vapor compression refrigeration system during induced transient regimes. Using experimental data, exergy destruction as a function of time under the influence of some factors that perturb the stationary regime, such as deactivation of piston, variation of mass flow rate and initial temperature of cooled fluid, and diminution of the compressor rotation speed, was calculated. Under the perturbation, an antagonistic increase in the coefficient of performance and a decrease in exergy efficiency were noted.

Frictional and Internal Leakage Losses in Rotary-Vane Two-Phase Refrigerating Expanders

2008 ◽  
Author(s):  
A. M. Mahmoud ◽  
S. A. Sherif ◽  
W. E. Lear
Keyword(s):  
Coefficient Of Performance ◽  
Geometrical Parameters ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Component Level ◽  
Two Phase ◽  
Level Model ◽  
Vapor Compression Refrigeration ◽  
Future Work ◽  
Fluid Parameters

Increasing the coefficient of performance of a vapor compression refrigeration system may be realized by utilizing work recovering expansion devices that lower the enthalpy of the refrigerant at the inlet of the evaporator. Depending on the operational and geometrical parameters of the expander, laminar and viscous two-phase leakage flow within the expander may be present. Single-phase leakage models available in the literature must then be modified or re-derived accordingly. A dynamic frictional model for the expander must also be developed for ideal operation (i.e. no internal leakage) and modified to account for internal leakage accordingly. This paper presents a comprehensive component-level model of inherent friction and internal leakage losses in a two-phase circular rotary-vane expander used in a vapor compression refrigeration system. The model establishes the performance of the expander as a function of geometric and fluid parameters. Accurate modeling and prediction of frictional and internal leakage losses is vital to being able to accurately estimate the efficiency, rotational speed, torque and power of/produced by the expander. Directions for future work are also discussed.

Sign in / Sign up

Export Citation Format

Share Document