Theoretical Rankine Coefficients Of Performance Research Articles

Thermodynamic screening of some HFCs and HFEs for high-temperature heat pumps as alternatives to CFC114

The theoretical performances of a few selected fluids, screened from about 30 hydrofluorocarbons and fluorinated ethers, have been comparatively assessed for high-temperature working fluids as alternatives to CFC114 by using some basic and derived heat pump parameters for an ideal Rankine cycle including pressure ratio, specific compressor displacement and theoretical Rankine coefficient of performance. The following fluids have been assessed: HFE134, HFC143, HFC236ca, HFC236cb, HFC236ea, HFC236fa and HFC254cb. While all the fluids assessed offer better COP values, HFC143 offers the best values. Use of HFC143 necessitates better safety design, owing to its flammability. HFE134 also offers attractive COP values next to HFC143.

Comparative assessment of some HCFCs, HFCs and HFEs as alternatives to CFC11

The theoretical performances of some hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), and hydrofluorinated ethers (HFEs) have been assessed as alternatives to CFC11 by using the standard refrigeration parameters including pressure ratio, specific compressor displacement and theoretical Rankine coefficient of performance. From this comparative analysis, it is evident that CFC11 is the best thermodynamically efficient fluid and HCFC123 is the fluid which offers features close to CFC11. A brief review of the current status of HCFC123, which is currently accepted as an interim substitute for CFC11, is also presented. Among the HFCs assessed, HFC245ca offers reasonable (COP) RR values with compressor sizes closer to CFC11. HFC143 is the best fluorinated ether as it offers efficiency very close to CFC11 but it requires relatively large size compressors. Perhaps HFE143 may be suitable for the lower range of cooling capacities currently covered by CFC11.

Derived thermodynamic design data for refrigeration and heat pump systems operating on HCFC-123

The current status of HCFC-123 as the alternative to CFC-11 in air-conditioning, refrigeration and heat pump systems is reviewed. The theoretical Rankine coefficient of performance (COP) and the pressure ratios (PR) have been presented for heat pumps operating on HCFC-123. Composite plots betwee pressure ratio, theoretical Rankine coefficient oerformance and ( T co -T EV ) for the appropriate temperature ranges of T EV and T CO are presented for HCFC-123 for refrigeration and heat pumps systems, respectively.

Assessment of HFCs, fluorinated ethers and amine as alternatives to CFC12: Evaluation des HFC, des éthers fluorés et de l'amine utilisés comme substituts du R12

The theoretical performance of some HFCs, fluorinated ethers and amine have been comparatively assessed as alternatives to CFC12 by using the standard refrigeration parameters, including pressure ratio, specific compressor displacement, theoretical Rankine coefficient of performance and shaft power per ton of refrigeration. From the energy point of view, HFC152a appears to be the best. HFC134 offers better efficiencies than HFC134a. Tetrafluorodimethyl ether (E134) also appears to be a potential candidate. A brief review of the current status of these fluids and the practical implications of their use is also presented.

Comparative assessment of HFC134a and some refrigerants as alternatives to CFC12

A composite plot relating evaporating temperature T EV, condensing temperature T CO, pressure ratio (PR) and theoretical Rankine coefficient of performance (COP) RR is presented for HFC134a. The theoretical performance of HFC134a has been comparatively assessed along with HCFC22, HFC134, HFC152a, HCFC124 and HCFC142b as alternatives to CFC12 by using the standard refrigeration parameters including pressure ratio, specific compressor displacement, theoretical Rankine coefficient of performance, shaft power per ton of refrigeration. A discussion of the practical implications of the choice of the alternatives to CFC12 is also presented.

Derived thermodynamic design data for heat pump systems operating on R1270

Theoretical Rankine coefficients of performance and the compression ratios have been presented for heat pump systems operating on R1270. These values are listed in tabular form for temperature lifts of 5–75°C and condensing temperatures of 12–90°C in one degree increments. A composite plot has been drawn to illustrate the feasible operating range of R1270 heat pump systems.

Derived thermodynamic design data for heat pump systems operating on R13

Theoretical Rankine coefficients of performance and the compression ratios have been presented for heat pump systems operating on R13. These values are listed in tabular form for temperature lifts of 5–75°C and condensing temperatures of 6–26°C in one degree increments. A composite plot has been drawn to illustrate the feasible operating range of R13 heat pump systems.

Derived thermodynamic design data for heat pump systems operating on R170

Theoretical Rankine coefficients of performance and the compression ratios have been presented for heat pump systems operating on R170. These values are listed in tabular form for temperature lifts of 5–75°C and condensing temperatures of 6–31°C in one degree increments. A composite plot has been drawn to illustrate the feasible operating range of R170 heat pump systems.

Derived thermodynamic design data for heat pump systems operating on R23

Theoretical Rankine coefficients of performance and the compression ratios have been presented for heat pump systems operating on R23. These values are listed in tabular form for temperature lifts of 5–75°C and condensing temperatures of 5–24°C in one degree increments. A composite plot has been drawn to illustrate the feasible operating range of R23 heat pump systems.

Derived thermodynamic design data for heat pump systems operating on R744

Theoretical Rankine coefficients of performance and the compression ratios have been presented for heat pump systems operating on R503. These values are listed in tabular form for temperature lifts of 10–55°C and condensing temperatures of 7–30°C in one degree increments. A composite plot has been drawn to illustrate the feasible operating range of R744 heat pump systems.

Derived thermodynamic design data for heat pump systems operating on R503

Theoretical Rankine coefficients of performance and the compression ratios have been presented for heat pump systems operating on R503. These values are listed in tabular form for temperature lifts of 5–75°C and condensing temperatures of 5–18°C in one degree increments. A composite plot has been drawn to illustrate the feasible operating range of R503 heat pump systems.

Heat pump assisted distillation. IV: An experimental comparison of R114 and R11 as the working fluid in an external heat pump

An experimental study has been carried out on a continuously operated pilot fractional distillation column equipped with an external heat pump. The distillation column was a 15 cm internal diameter glass unit containing eleven single bubble cap plates. A methanol-water mixture was fed to the column. After operating the heat pumps with R114 as the working fluid, further experiments have been conducted with R11 as the working fluid. Plots of pressure against enthalpy, condensation pressure and latent heat of vaporization against condensation temperature and theoretical Rankine coefficient of performance against gross temperature lift and condensation temperature are presented for both R114 and R11. R11 has correspondingly higher theoretical Rankine coefficients of performance than R114. The experiments show that the actual coefficients are also higher for R11 than for R114. A maximum actual coefficient of performance of 5.3 was obtained using R11 as the working fluid with a gross temperature lift of 38.4°C. The experimental data for R11 were found to be reproducible during operation over a number of weeks. This showed that the relative thermal instability of R11 compared to R114 had not apparently affected the performance of the system.

Derived thermodynamic design data for heat pump systems operating on R504

Theoretical Rankine coefficients of performance and the compression ratios have been presented for heat pump systems operating on R504. These values are listed in tabular form for temperature lifts of 10–75°C and condensing temperatures of 15–50°C in 5°C increments. A composite plot has been drawn to illustrate the feasible operating range of R504 heat pump systems.

Derived thermodynamic design data for heat pump systems operating on R13B1

Theoretical Rankine coefficients of performance and compression ratios have been presented for heat pump systems operating on R13B1. These values are listed in tabular form for temperature lifts of 10–75°C and condensing temperatures of 15–50°C in 5°C increments. A composite plot has been drawn to illustrate the feasible operating range of R13B1 heat pump systems

Derived thermodynamic design data for heat pump systems operating on R152a

Theoretical Rankine coefficients of performance and the compression ratios have been presented for heat pump systems operating on R152a. These values are listed in tabular form for temperature lifts of 10–75°C and condensing temperatures of 20–85°C in 5°C increments. A composite plot has been drawn to illustrate the feasible operating range of R152a heat pump systems.

The prediction of the coefficient of performance of vapour compression heat pumps

Equations are presented which relate the actual value of the coefficient of performance of a heat pump to the theoretical Rankine coefficient of performance by efficiencies which depend upon the compression ratio and the design of the particular heat pump system. It is shown that the comparison of prediction of the coefficient of performance with measured values give possibilities for preliminary design of heat pump systems.

Comparison of theoretical rankine heat pump cycle performance data for twenty-one working fluids

The compression ratio (CR) is largely determined by the choice of compressor in a mechanical vapour compression heat pump system. The condensing temperature T CO is largely determined by the required temperature of the heat to be delivered. This means that for a given working fluid, the theoretical Rankine coefficient of performance (COP) R and the gross temperature lift ( T CO − T EV ) are determined automatically. The only way that the values of (COP) R and ( T CO − T EV ) can be varied is to choose another working fluid. Of the twenty-one working fluids for which comprehensive thermodynamic data are available, only ten have critical temperatures high enough to be considered for use in heat pump systems with a condensing temperature of 120°C and only five can be considered for a condensing temperature of 160°C. Values of (COP) R and ( T CO − T EV ) are listed for compression ratios (CR) of 3, 4, 5 and 6 for condensing temperature T CO of 100, 120 and 160°C respectively.

Derived thermodynamic design data for heat pump systems operating on R717

The theoretical Rankine coefficient of performance and the compression ratios have been presented for heat pump systems operating on R717. These values are listed in tabular form for temperature lifts of 10–75°C and condensing temperatures of 15–115°C in 5°C increments. Several graphs have been drawn to illustrate the feasible operating range for R717 heat pump systems. These derived thermodynamic data can be used for the rapid preliminary design of heat pump systems operating on R717.

Derived thermodynamic design data for heat pump systems operating on R142b

The theoretical Rankine coefficients of performance (COP) R and the compression ratios have been presented for heat pumps operating on R142b. These values are listed in tabular form for temperature lifts of 10–75°C and for condensing temperatures T CO of 15–100°C in 5°C increments. Several graphs have been drawn to illustrate the feasible operating range for R142b heat pump systems. The derived thermodynamic data can be used for the rapid preliminary design of heat pump systems operating on R142b.

Derived thermodynamic design data for heat pump systems operating on R115

The theoretical Rankine coefficients of performance and the compression ratios have been presented for heat pump systems operating on R115. These values are listed in tabular form for temperature lifts of 10–75°C and the condensing temperatures of 15–65°C in 5°C increments. Several graphs have been drawn to illustrate the feasible operating range for R115 heat pump systems. The derived thermodynamic design data can be used for the rapid preliminary design of heat pump systems operating on R115.