Reducing the amount of required propane refrigerant in the condenser of a commercial air-conditioner by increasing the inlet temperature

The use of synthetic refrigerants in the refrigeration and air conditioning sector is now obsolete due to the fact that they are not environmental friendly. They damage ozone layer and cause global warming which have both direct and indirect adverse effects on humans and environment. Today, the use of alternative refrigerants is well accepted. Hydrocarbon refrigerants are natural compounds, which do not damage the ozone layer, and have very little impact on global warming. The use of a simple hydrocarbon, propane, as a refrigerant is becoming increasingly popular these days due to its high heat capacity and its short lifetime in the atmosphere. However, since propane is extremely flammable, it is prudent to minimize the amount of propane in the system in order to reduce the risks associated with leakage of the explosive gas. In this research, the possibility of reducing the mass of propane in the condenser without sacrificing the heat transfer capacity of the system has been investigated. In an air-conditioner or refrigeration system, condenser accommodates the most mass of the refrigerant compared with those in the other parts of the system. A MATLAB script has been developed which model the performance of a commercial portable air-conditioner. The results show that by increasing the working temperature of condenser from 30oC to 46oC at the ambient temperature of 27oC, about forty percent propane mass saving is achievable. These temperatures are still far below the critical (370oC) and auto-ignition (540oC) temperatures of propane

Perencanaan Pengolah Sampah pada Lokasi Wisata Religi Sa’pak Bayo-bayo Kabupaten Tana Toraja

Pada suatu tujuan wisata, banyak hal yang perlu diperhatikan sebelum lokasi tersebut diperkenalkan kepada masyarakat. Seperti ketersediaan fasilitas untuk pengunjung, khususnya fasilitas-fasilitas penting seperti toilet dan tempat sampah. Salah satu fasilitas yang dibahas pada kegiatan ini adalah masalah sampah. Pada lokasi wisata religi Sa’pak Bayo-bayo telah tersedia tempat sampah yang dapat dipergunakan oleh pengunjung. Dikarenakan sampah organik cukup banyak maka oleh pengelolah, bekerja sama dengan Universitas Atma Jaya Makassar membutuhkan analisis pengolahan dan pemanfaatan sampah oprganik pada lokasi wisata tersebut. Setelah melakukan survey lokasi dan wawancara dengan pengelolah mengenai sampah organik maka direkomendasi untuk pengadaan mesin pencacah sampah skalah 1 m3 per hari untuk mencacah sampah organik berupa daun dan ranting kecil. Cacahan sampah tersebut diolah menjadi pupuk organik dan material penutup permukaan tanah. Mengingat ketebalan tanah permukaan lokasi yang dangkal. Pentingnya pengolahan sampah organik untuk mengatasi masalah pembuangan serta pemanfaatan sampah menjadi sesuatu yang berguna. Rekomendasi untuk pengolahan sampah organik pada lokasi wisata religi Sa’pak Bayo-bayo adalah mesin pencacah material organik dengan kapasitas 69 kg/jam. Dengan mengolah sampah organik menjadi cacahan, tumpukan sampah tidak perlu lagi dibakar tetapi dimanfaatkan menjadi penutup permukaan tanah dan pupuk organik kering

PENGARUH SUDUT KEMIRINGAN KATUP BUANG DAN DIAMETER PIPA MASUKAN POMPA HIDRAM TERHADAP TEKANAN OUTPUT MAKSIMUM

Pada masa sekarang ini, penggunaan energi yang tidak terbaharukan seperti energi fosil sudah mulai dikurangi dan diganti dengan energi alternatif yaitu energi terbaharukan. Hal ini dikarenakan sumber energi tidak terbaharukan seperti energi fosil semakin berkurang sekarang ini. Untuk itu kita perlu untuk mencari dan menggunakan energi alternatif dari sumber energi terbaharukan. Hal ini disebabkan karena energi terbaharukan tersedia setiap saat.  Seperti pada penelitian ini yang menggunakan sebuah mekanisme pendorong air tanpa menggunakan energi darti luar yaitu dengan menggunakan pompa hidram. Penelitian ini dilakukan secara eksperimental dengan menganalisa pengaruh sudut kemiringan katup buang pompa hidran dan diameter pipa suplai terhadap tinggi maksimum yang dapat dicapai oleh air hasil pemompaan pompa hidram. Dari hasil penelitian dengan menggunakan pompa hidram berukuran ¾ in, diperoleh bahwa tinggi maksimum air pemompaan adalah 17.859 m pada pipa suplai berdiameter ¾ in dan sudut kemiringan 30.2º. Sedangkan pada pipa suplai dengan diameter 1.5 in, memberikan tinggi maksimum 11.960 m pada sudut kemiringan pompa 27.3Â

Impacts of room temperature on the performance of a portable propane air conditioner

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

Extending the capillary tube of a propane air-conditioner to reduce the refrigerant charge

Hydrocarbon refrigerants are employed to replace synthetic refrigerants due totheir low global warming and ozone depletion potentials; however, these refrigerants are flammable; therefore, their mass in the system should be minimized to reduce the associated risks. This study deals with the novelidea of extending the capillary tube of a portable air-conditioner in orderto decrease the amount of refrigerant charge in the system. Extending the length of the capillary tube will shorten thelength of the liquid line in applications in which the distance between theoutlet of the condenser and the inlet of the evaporator cannot be reduced. A script was developed and its accuracywas experimentally assessed.It was then used to estimate the amount of charge for the existing design and the extended capillary tube. The results show a significant reduction (63.9%) in the amount of propane in the capillary tubeand liquid line, and a reasonable decrease (8.3%) in the maximumspeed of refrigerant for the airconditioner used in this work

PEMANFAATAN UDARA PANAS KONDENSOR MESIN PENDINGIN SEBAGAI SUMBER ENERGI PEMANAS AIR RUMAH TANGGA

The use of energy is important today due to the rapid decrease in fossil energy entire the world. The world should consider of using energy as efficient as possible. Waste energy from engines and other energy converters is released as hot air in the atmosphere. Waste heat energy is able to recover by using water heat exchanger. This research aims to experimentally examining the use of waste heat from room air conditioner as home energy source. A cross flow concentric pipe heat exchanger is used as the condenser for a room air conditioner to cover the exhaust energy from the condenser. The results shows that by using a concentric pipe condenser, the exhaust energy is benefit to decrease the paid energy equal to Rp. 57.000,-  monthly electricity bill. The other supplementary beneficial equal to Rp. 564.249,- electricity bill gained from exhaust energy of the air conditioner.    Keywords: : hot air, energy sourc

KINERJA TURBIN ANGIN DARRIEUS DUA SUDU GERAK BERPROFIL NACA 0028 SECARA EKSPERIMEN

Wind energy is one type of renewable energy which is not only clean andenvironmentally friendly but also has abundant and is obtained free of charge in the natural. The process of converting kinetic energy in the wind into mechanical energy requires a turbine. Darrieus turbine is a device that converts wind energy that moves from various directions into mechanical energy on a shaft that moves in one direction. This study aims to determine the performance of a two-blade Darrieus turbine with the NACA 0028 profile experimentally. The wind tunnel, Darreus turbine, and load-bearing construction were designed and manufactured by researchers. Data collection of wind velocity, load, and rotation using standard equipment. The results of the study show that the turbine power coefficients are 35.57%, 23.55%, 23.2%, and 20.05% at wind velocity of 6.04, 7.08, 7.25, and 7.59 m/s, respectively

A study on the performance of a portable single-duct propane air conditioner and ways of reducing the amount of refrigerant

The Abstract is currently unavailable, due to the thesis being under Embargo

Effect of Inlet Pressure, Size and Wind Speed of an Evaporator on Amount of Refrigerant Charge and Performance of a Portable Propane Air Conditioner

Previous studies show that propane refrigerant has good performance in air conditioners, but the drawback of its flammability needs attention. The propane air conditioner should be designed for minimum refrigerant charge. In this work, the amount of refrigerant charge and cooling capacity of the air conditioner are the focus of analysis. The effect of the evaporator's variation of inlet pressure and variation of air speed over the evaporator on cooling capacity and amount of refrigerant within the evaporator are discussed. This research is mainly computational work with limited experimental validation. We found that, for a single duct portable propane air conditioner, cooling capacity increases from 0.956 kW to 4.319 kW when the inlet pressure of the evaporator is changed from 0.8 MPa to 0.4 MPa. Under the same condition, the accumulated refrigerant mass within the evaporator decreases from 176.846 g to 67.768 g. Increase in air speed over the evaporator increases the cooling capacity from 3.208 kW to 4.275 kW when the air speed increases from 1.0 m/s to 3 m/s, while refrigerant mass decreases from 110.307 g to 68.033 g. It should be noted that, at the lower inlet pressure of the evaporator, frost quickly appears on evaporator coils

Performance of a single-duct portable propane air conditioning system under different refrigerant charge levels

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