01-01-2013, 04:55 PM
Thermodynamic Optimization of Household Refrigerator Using Propane –Butane as Mixed Refrigerant
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Abstract
A household refrigerator designed to work with R-134a was used as an investigation unit to assess the prospect of using mixed refrigerants. The recital of the refrigerator using mixed refrigerant was investigated and compared with the performance of refrigerator when R-134a was used as refrigerant. The effect of condenser temperature and evaporator temperature on COP, refrigerating effect was investigated. The energy consumption of the refrigerator during experiment with mixed refrigerant and R-134a was measured. The outcome shows the permanent running and cycling results showed that R134a with a charge of 100 g or mixed refrigerant with charge of 80 mg or more satisfy the required freezer air temperature of −12 °C. The lowest electric energy consumption was achieved using mixed refrigerant with heat level is less than -15oC. This mixture achieved higher volumetric cooling capacity and lower freezer air temperature compared to R134a. Experimental results of the refrigerator using mixed refrigerant were compare with those using R134a. Pull-down time, pressure ratio and power consumption of mixed refrigerant refrigerator were under those of R134a refrigerator by about 7.6%, 5.5% and 4.3%, respectively. Also, actual COP of mixed refrigerant refrigerator was higher than that of R134a by about 7.6%. Lower on-time ratio and energy consumption of mixed refrigerant refrigerator by nearly 14.3% and 10.8%, respectively, compared to those of R134a refrigerator were achieved. The COP and other result obtain in this experiment show a positive indication of using mixed refrigerant as refrigerants in household refrigerator.
INTRODUCTION
Normal frost was disseminated and used in both commercial and domicile application in the middle of 1880s to refrigerate food. The suggestion that cold could be produced by the forced evaporation of an impulsive liquid under reduced had been previously pursued by William Cullen in the eighteenth century. A refrigerator is a cooling appliance comprising a thermally insulated screened-off area and a heat pump - element or perfunctory means - to transfer heat from it to the external atmosphere cooling the contents to a temperature below ambient. Refrigerators are extensively used to store foods which deteriorate at ambient temperatures; spoilage from bacterial growth and other processes is much slower at low temperatures.
Test Procedure The system was evacuated with the help of vacuum pump to remove the moisture and charged with the help of charging system. The temperature inside the chamber was maintained at 25°C and 28°C. When the temperature and humidity inside the chamber was at steady state, the experiments were started. The experiment has been conducted on the domestic refrigerator at no load and closed door conditions.
RESULTS AND DISCUSSIONS
From this section the comparison of the performance parameter of the refrigerants and energy consumption by the refrigerator was discussed This investigation deals with mixed refrigerant (hydrocarbon mixtures of propane, butane and isobutane) in order to assess their feasibility for replacing HFC-134a in refrigeration systems by comparing their relevant parameters.
The refrigerating effect is the main purposes of the refrigeration system. The liquid refrigerant at low pressure side enters the evaporator. As the liquid refrigerant passes through the evaporator coil, it continually absorbs heat through the coil walls, from the medium being cooled. During this, the refrigerant continues to boil and evaporate. Finally the entire refrigerants have evaporated and only vapor refrigerant remains in the evaporator coil.
CONCLUSION
This project invested an ozone friendly, energy efficient, user friendly, safe and cost-effective alternative refrigerant for HFC134a in domestic refrigeration systems. After the successful investigation on the performance of mixed refrigerants the following conclusions can be drawn based on the results obtained. This experimental investigation carried out to determine the performance of a domestic refrigerator when a propane/butane mixture is used as a possible replacement to the traditional refrigerant R134a.
[attachment=46079]
Abstract
A household refrigerator designed to work with R-134a was used as an investigation unit to assess the prospect of using mixed refrigerants. The recital of the refrigerator using mixed refrigerant was investigated and compared with the performance of refrigerator when R-134a was used as refrigerant. The effect of condenser temperature and evaporator temperature on COP, refrigerating effect was investigated. The energy consumption of the refrigerator during experiment with mixed refrigerant and R-134a was measured. The outcome shows the permanent running and cycling results showed that R134a with a charge of 100 g or mixed refrigerant with charge of 80 mg or more satisfy the required freezer air temperature of −12 °C. The lowest electric energy consumption was achieved using mixed refrigerant with heat level is less than -15oC. This mixture achieved higher volumetric cooling capacity and lower freezer air temperature compared to R134a. Experimental results of the refrigerator using mixed refrigerant were compare with those using R134a. Pull-down time, pressure ratio and power consumption of mixed refrigerant refrigerator were under those of R134a refrigerator by about 7.6%, 5.5% and 4.3%, respectively. Also, actual COP of mixed refrigerant refrigerator was higher than that of R134a by about 7.6%. Lower on-time ratio and energy consumption of mixed refrigerant refrigerator by nearly 14.3% and 10.8%, respectively, compared to those of R134a refrigerator were achieved. The COP and other result obtain in this experiment show a positive indication of using mixed refrigerant as refrigerants in household refrigerator.
INTRODUCTION
Normal frost was disseminated and used in both commercial and domicile application in the middle of 1880s to refrigerate food. The suggestion that cold could be produced by the forced evaporation of an impulsive liquid under reduced had been previously pursued by William Cullen in the eighteenth century. A refrigerator is a cooling appliance comprising a thermally insulated screened-off area and a heat pump - element or perfunctory means - to transfer heat from it to the external atmosphere cooling the contents to a temperature below ambient. Refrigerators are extensively used to store foods which deteriorate at ambient temperatures; spoilage from bacterial growth and other processes is much slower at low temperatures.
Test Procedure The system was evacuated with the help of vacuum pump to remove the moisture and charged with the help of charging system. The temperature inside the chamber was maintained at 25°C and 28°C. When the temperature and humidity inside the chamber was at steady state, the experiments were started. The experiment has been conducted on the domestic refrigerator at no load and closed door conditions.
RESULTS AND DISCUSSIONS
From this section the comparison of the performance parameter of the refrigerants and energy consumption by the refrigerator was discussed This investigation deals with mixed refrigerant (hydrocarbon mixtures of propane, butane and isobutane) in order to assess their feasibility for replacing HFC-134a in refrigeration systems by comparing their relevant parameters.
The refrigerating effect is the main purposes of the refrigeration system. The liquid refrigerant at low pressure side enters the evaporator. As the liquid refrigerant passes through the evaporator coil, it continually absorbs heat through the coil walls, from the medium being cooled. During this, the refrigerant continues to boil and evaporate. Finally the entire refrigerants have evaporated and only vapor refrigerant remains in the evaporator coil.
CONCLUSION
This project invested an ozone friendly, energy efficient, user friendly, safe and cost-effective alternative refrigerant for HFC134a in domestic refrigeration systems. After the successful investigation on the performance of mixed refrigerants the following conclusions can be drawn based on the results obtained. This experimental investigation carried out to determine the performance of a domestic refrigerator when a propane/butane mixture is used as a possible replacement to the traditional refrigerant R134a.