6 research outputs found
STUDI EKSPERIMENTAL PENGARUH JUMLAH LUBANG DISTRIBUTOR UDARA TERHADAP KARAKTERISTIK GELEMBUNG PADA BUBBLING FLUIDIZED BED DENGAN VARIASI PARTIKEL BED
The aim of research is to determine the effect of air distributor on bubble
characteristics, that cove
ANALISIS PENGARUH PENGGUNAAN REFRIGERAN SEKUNDER DAN RETROFITTING TERHADAP KINERJA MINI FREEZER
Small refrigeration unit systems, with a capacity compressor of under a half HP,
commonly are used in small shops, ice cream shop or storage of products / frozen foods. Such
systems generally use a direct expansion refrigeration systems without secondary refrigerant
in which direct contact occurs between the evaporator and the product. The weakness of this
system is the cabin temperature easily to change as effect of the cooling load from the outside
or the environment. On the other hand there is a refrigeration system equipped with secondary
refrigerants, propylene glycol mixed with water, which could minimize the effect of load from
outside. Refrigeration system using secondary refrigerant commonly used in large units, such
as to produce ice cube. The use of secondary refrigerant are aimed to maintain the
temperature of the cabin for longer than a system using direct expansion. The ability to
maintain temperature of the cabin longer results in smaller electrical energy consumption. The
purpose of this research is to study the performance and electrical energy consumption as
effect of variying primary refrigerant, expansion valve, and secondary refrigerant used in the
system.
The experiment was conducted on a mini freezer with dimension of 66 x 54.5 x 46.5
(cm) which is provided with two expansion devices, thermostatic expansion valve and
cappilary tube, and some spaces that can be filled with secondary refrigerant. The results
show that the consumption of electrical energy were decrease, in a system without a
secondary refrigerant thes average of electrical energy consumption for a period of one hour
were around 0.274 kWh while the system equipped with secondary refrigerant was
0.254 kWh. Performance of arefrigeration system with higher concentration of secondary
refrigerant show better results with the average efficiency of about 78.6%. The results showed
the influence of refrigerant retrofitting the electrical energy consumption savings were of
about 11.3%. While the performance of refrigeration systems that used expansion device of
thermostatic expansion valve type showed relatively similar results with a refrigeration
system that used a capillary tube. The results show that the refrigeration system equipped with
secondary refrigerant could be used as a substitute for direct expansion refrigeration system
for a small capacity