The performance of a portable propane air conditioner system, in which the temperatures of the air passing over the condenser and evaporator are equal, has been experimentally investigated under different room temperatures and refrigerant charge levels. The research has been carried out in a range of room temperatures from 20°C to 35°C and in undercharge, standard charge and overcharge conditions. The results show that, at higher room temperatures, the refrigerant temperature in all parts of the system, the density of the refrigerant at the inlet and outlet of the condenser, mass of the refrigerant in the compressor, the mass flow rate of the refrigerant and the cooling capacity of the system in either the undercharge or full charge condition, the specific cooling capacity of the undercharge system, the useful work of the compressor, and the maximum pressure of the refrigerant increase. The increase in room temperature decreases the density of the refrigerant at the inlet and outlet of the capillary tube, the mass of the refrigerant in the capillary tube, the refrigerant subcooling at the inlet of the capillary tube, the maximum velocity of the refrigerant and the coefficient of performance. In addition, the increase in room temperature at overcharge condition causes an increase in the mass flow rate, cooling capacity and specific cooling capacity to a maximum value followed by their decrease. The most important difference between a portable air-conditioner and a non-portable system is the increase in cooling capacity with an increase in room temperature in full charge condition.

The effects of the refrigerant charge on the performance of a portable propane air conditioning system have been evaluated and compared to nonportable systems in which the surrounding temperatures of the evaporator and condenser are not equal. This study aims to determine the similarities and differences in the performance of the two types of propane air conditioners under different charge levels, and to serve as a source of reference for future designs of portable air conditioners. The refrigerant charge was changed from −12.3% to +30% of its normal charge at several room temperatures ranging from 20 °C to 35 °C. The performance parameters include the refrigerant temperature, mass flow rate, maximum velocity of refrigerant, maximum pressure, cooling capacity, compressor work, specific cooling capacity, and coefficient of performance of the system. It has been found that an increase in charge level was found to increase the cooling capacity, coefficient of performance, and maximum velocity of refrigerant in the system while decreasing specific cooling capacity. The increase in the charge caused a relatively insignificant rise in the maximum pressure of the system and useful work of the compressor.

No abstract

The negative impacts of synthetic refrigerant on the environment are ozone depletion and global warming. In spite of all the new refrigerants has no ozone depletion potential (ODP), only the existing refrigerant R22 has ODP as 0.055, however, the global warming potential of the new refrigerants are high. Therefore the use of environmentally friendly refrigerants is a must. Propane (R290) and isobutene (R600a) are environmentally friendly refrigerants as the refrigerants have no ODP and negligible GWP. R290 is more efficiently than R22 because R290 has higher COP. One should be noted of two refrigerants, R290 and R600a is their flammability. Therefore, the amount of R290 or R600a should be minimized in refrigeration or air conditioning system. This research is conducted experimentally and theoretically comparing the effect of physical properties on the heat transfer process of the low mass of R290 and R290 -R600a blends. An increase in vapor quality decreases the convective heat transfer coefficient. This is due to the decrease in thermal conductivity and specific heat of the refrigerant with an increase in the vapor quality. R290 has the highest convective heat transfer coefficient while 60%R290 -40%R600a blend has the lowest convective heat transfer coefficient.

Saat ini penggunaan energi menjadi hal yang sangat menarik. Energi fosil ketersediaannya semakin menipis. Sehingga perlu perhitungan saat menggunakan energi fosil. Di sekitar kita terdapat banyak energi yang terbuang dalam bentuk kalor dalam bentuk udara panas. Jika energi tersebut dipindahkan ke fluida lain, maka energi buangan dapat dipergunakan sebagai energi berguna. Penelitian ini membahas tentang penggunaan energi buang mesin pendingin ruangan menjadi sumber energi rumah tangga dengan menyerap panas buangan menggunakan air konsumsi rumah tangga. Alat penukar kalor yang digunakan adalah pipa konsentrik aliran berlawanan Hasil penelitian menunjukkan bahwa dengan menggunakan penukar kalor pipa konsentrik sebagai pengganti kondensor memberikan penghematan energi setara energi listrik Rp. 57.000,-perbulan. Juga diperoleh manfaat tambahan setara Rp 564.249,-energi listrik perbulan.