An experimental evaluation of R11 as a heat pump working fluid in comparison with some other working fluids

1983 ◽  
Vol 7 (2) ◽  
pp. 129-135
Author(s):  
S. E. Ogbeide ◽  
S. A. K. El-Meniawy ◽  
S. Devotta ◽  
F. A. Watson ◽  
F. A. Holland
Keyword(s):  
Heat Pump ◽  
Experimental Evaluation ◽  
Working Fluid ◽  
Working Fluids

Performance Assessment of Blends of CO2 With Eco-Friendly Working Fluids for Heat Pump Applications

2013 ◽  
Author(s):  
Xiaowei Fan ◽  
Xianping Zhang ◽  
Xinli Wei ◽  
Fang Wang ◽  
Xiaojing Zhang
Keyword(s):  
Heat Pump ◽  
Mass Fraction ◽  
Experimental Results ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Outlet Temperature ◽  
Pump System ◽  
Heat Rejection ◽  
Working Fluids ◽  
Optimum Heat

Since pure CO2 as refrigerant has some disadvantages failing to meet requirements, binary blends of CO2 (or R744) with other eco-friendly working fluids, R290, R1270, R170, RE170 and HFC134a are proposed in this paper to be used for medium temperature heat pump systems. The eco-friendly refrigerant mixtures can reduce the heat rejection pressure as that for pure CO2, and meanwhile suppress the flammability, explosivity as that for pure HCs or RE170. Based on the pinch point of heat transfer, the numerical models of heat pump cycle using CO2-based mixture are developed. With a comprehensive consideration of heating coefficient of performance (COPh), optimum heat rejection pressure, volumetric heating capacity, discharge temperature, the binary mixture CO2/R290 is determined as the most suitable working fluid for the given heat pump application. Compared to pure CO2, the optimum heat rejection pressure of mixture for 95/5, 90/10, 85/15 and 80/20 is decreased by 0.82, 0.94, 1.06 and 1.86MPa respectively for heat sink outlet temperature of 65°C. The experimental testrig is designed and set up for the transcritical heat pump system. The experimental study with different CO2 mass fraction has been carried out, which conducts a study on the variations of heat pump performance, component’s mass fraction and working fluid charge. The experimental results validated the CO2/R290 natural mixture proposed in theory. The experimental results provide useful references on the optimization and improvement of CO2/R290 heat pump testrig.

Investigation on Potential Working Fluids for Waste Heat Recovery Applications

2016 ◽  
Vol 819 ◽  
pp. 142-146
Author(s):  
Ralf Struzyna ◽  
Andreas Menne ◽  
Jens Steinmill
Keyword(s):  
Fuel Consumption ◽  
Experimental Evaluation ◽  
Waste Heat ◽  
Thermodynamic Simulation ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Process Conditions ◽  
Condensation Temperature ◽  
Working Fluids ◽  
The Stability

Since topics like the greenhouse effect and the associated global warming issue are much more discussed in the past, automobile manufacturers have to become even more active in in two fields: reduction of fuel consumption and reduction of emissions. As the optimization of motor vehicles has reached a point at which significant additional fuel saving cannot be achieved by means of purely engine-internal measures alone, other systems must be found to improve the specific fuel consumption. One promising technology could be the use of engine waste heat contained in exhaust gas. Earlier studies have shown, besides systems like thermoelectric generators or a Turbo compounding system, an integrated Rankine Cycle offers a lot of potential to turn waste heat into mechanical or electrical power. The use of a suitable working fluid for this Rankine Cycle is required to achieve a maximum in system power output. The aim of this work is to investigate the suitability of working fluids for automotive Organic Rankine Cycle applications. The investigation is focused on the thermodynamic simulation on the one hand and the experimental evaluation of thermal stability of the fluids on the other hand. For the experimental evaluation of the stability a continuous cycle is used to achieve nearly equal process conditions. The stability tests start with a short time screening of all selected fluids, later on the most promising ones are tested in long time test runs. In the test runs, the substances of the categories alkanes, cycloalkanes, monoaromatics and fluorinated compounds show best results regarding stability. In contrast acetales, siloxanes and ethers are not stable under the selected conditions. The same applies to ethanol. With a temperature above 225 °C ethanol is not stable. Additional runs with ethanol show that the temperature has to be limited to below 250 °C at least to avoid a high decomposition. Also acetone reacting products can be found in the liquid phase leading to high boiling substances that then may lead to coke formation in the system. The validation of the tested and simulated fluids is done for two different condensation temperatures (CT) of 100°C and 40°C. Fluids acetone and ethanol (CT 100°C) show best overall results. In Addition fluids n-hexane, methylcyclohexane, cyclohexane and toluene show good upto very good results. For condensation temperature 40°C, cyclopentane and R1233zd is suggested.

Development and Experimental Study of New Working Fluids for Moderate-High-Temperature Heat Pumps

2012 ◽  
Vol 468-471 ◽  
pp. 1313-1321
Author(s):  
Shi Jie Liu ◽  
Wen Sheng Yu ◽  
Wu Chen
Keyword(s):  
High Temperature ◽  
Heat Pump ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Working Fluids ◽  
Heating Efficiency ◽  
Temperature Heat ◽  
Performance Results ◽  
High Temperature Heat Pump

Some suggestions for developing new working fluids for moderate-high-temperature heat pump with excellent thermal and environmental performance were given firstly in this paper. The theoretical and experimental performance analysis of new-developed working fluids M1-M6 was carried out. The theoretical performance results showed that M1-M6 had high heating efficiency and GWP (Global Warming Potential) of M2 was less than 150. The experimental results showed that M5 had higher thermal efficiency than other two working fluids under same working condition. At the ambient temperature respectively of 30 Centigrade Degree and 40 Centigrade Degree, it took 70 and 65 minutes by the heat pump charged with M5 as working fluid to heat 100 liters of water respectively from 30 Centigrade Degree to 80 Centigrade Degree. Meanwhile the system’s COP (Coefficient of Performance) was respectively 2.9 and 3.0.

Performance Analysis and Comparison Study of Transcritical Power Cycles Using CO2-Based Mixtures as Working Fluids

2016 ◽  
Author(s):  
Jiaxi Xia ◽  
Jiangfeng Wang ◽  
Pan Zhao ◽  
Dai Yiping
Keyword(s):  
Critical Temperature ◽  
Parametric Optimization ◽  
Design Parameters ◽  
Working Fluid ◽  
Comparison Study ◽  
Software Environment ◽  
Working Fluids ◽  
Power Cycles ◽  
Power Cycle ◽  
Thermodynamic Performance

CO2 in a transcritical CO2 cycle can not easily be condensed due to its low critical temperature (304.15K). In order to increase the critical temperature of working fluid, an effective method is to blend CO2 with other refrigerants to achieve a higher critical temperature. In this study, a transcritical power cycle using CO2-based mixtures which blend CO2 with other refrigerants as working fluids is investigated under heat source. Mathematical models are established to simulate the transcritical power cycle using different CO2-based mixtures under MATLAB® software environment. A parametric analysis is conducted under steady-state conditions for different CO2-based mixtures. In addition, a parametric optimization is carried out to obtain the optimal design parameters, and the comparisons of the transcritical power cycle using different CO2-based mixtures and pure CO2 are conducted. The results show that a raise in critical temperature can be achieved by using CO2-based mixtures, and CO2-based mixtures with R32 and R22 can also obtain better thermodynamic performance than pure CO2 in transcritical power cycle. What’s more, the condenser area needed by CO2-based mixture is smaller than pure CO2.

Multi-Fluid Gas Turbine Components Scaling for a Generation IV Nuclear Power Plant Performance Simulation

2018 ◽  
Author(s):  
Emmanuel O. Osigwe ◽  
Arnold Gad-Briggs ◽  
Theoklis Nikolaidis ◽  
Pericles Pilidis ◽  
Suresh Sampath
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Gas Turbine ◽  
Nuclear Power ◽  
Working Fluid ◽  
Simulation Tool ◽  
Closed Cycle ◽  
Performance Simulation ◽  
Working Fluids ◽  
Component Map

One major challenge to the accurate development of performance simulation tool for component-based nuclear power plant engine models is the difficulty in accessing component performance maps; hence, researchers or engineers often rely on estimation approach using various scaling techniques. This paper describes a multi-fluid scaling approach used to determine the component characteristics of a closed-cycle gas turbine plant from an existing component map with their design data, which can be applied for different working fluids as may be required in closed-cycle gas turbine operations to adapt data from one component map into a new component map. Each component operation is defined by an appropriate change of state equations which describes its thermodynamic behavior, thus, a consideration of the working fluid properties is of high relevance to the scaling approach. The multi-fluid scaling technique described in this paper was used to develop a computer simulation tool called GT-ACYSS, which can be valuable for analyzing the performance of closed-cycle gas turbine operations with different working fluids. This approach makes it easy to theoretically scale existing map using similar or different working fluids without carrying out a full experimental test or repeating the whole design and development process. The results of selected case studies show a reasonable agreement with available data.

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