This paper describes thermal modeling of Vapor Compression Refrigeration System using R134a in primary circuit and AL2O3-Water based nanofluids in secondary circuit. The model uses information of the secondary fluids input conditions geometric characteristics of the system, size of nanoparticles and the compressor speed to predict the secondary fluids output temperatures, the operating pressure...

Selection of spiral capillary tube for refrigeration appliances and the effect of changes in the parameters such as capillary tube dimensions i.e. capillary tube diameter, coil pitch, capillary tube length and inlet conditions of refrigerant to the capillary tube i.e. degree of subcooling, inlet pressure on the mass flow rate of the refrigerant, also investigation about the coiling effect of sp...

The paper focuses on operation of simple refrigeration cycles and considers the selection of controlled variables for two different cycles. One is conventional sub-critical ammonia refrigeration cycle and the other is a trans-critical CO refrigeration cycle. There is no fundamental difference 2 etween the two cycles in terms of degrees of freedom and operation. However, in practical operation t...

A new model is presented to describe an irreversible absorption refrigerator, in which not only the irreversibilities of heat conduction but also the irreversibilities resulting from the friction, eddy and other irreversible effects inside the working fluid are considered. The influence of these irreversible effects on the performance of an absorption refrigerator with continuos flow is investi...

This paper describes a methodology for remote performance monitoring of retail refrigeration systems. The proposed framework starts with monitoring of the whole refrigeration circuit which allows detecting deviations from expected behavior caused by various faults and degradations. The subsequent diagnostics methods drill down deeper in the equipment hierarchy to more specifically determine roo...

Studied is a kind of NH3/CO2 two-stage low temperature refrigeration system, in which NH3 is used as the refrigerant in the high-temperature stage and CO2 is used as the refrigerant in the low-temperature stage. The performance of the system is simulated and analyzed by changing the mean temperature of the evaporator-condenser and the temperature of the condenser. The mean temperatures of the e...

Commercial refrigeration systems consumed 1.21 Quads of primary energy in 2010 and are known to be a major source for refrigerant charge leakage into the environment. Thus, it is important to study the environmental impact of commercial supermarket refrigeration systems and improve their design to minimize any adverse impacts. The system's Life Cycle Climate Performance (LCCP) was presented as ...

Low temperature process cooling is an energy demanding part in many chemical production processes. Cooling systems operating at very low temperatures consume a large amount of high quality energy such as electricity or high pressure steam, used to drive refrigeration compressor units. Hence decreasing refrigeration load can make a major improvement on the process energy balance. In industrial p...

OBJECTIVES This study evaluated the effect of refrigeration at 4 degrees C and post-refrigeration times (immediate, 5, 10, 15, or 20 min) on the viscosity and conversion kinetics of adhesive bonding resins. METHODS Scotchbond Dual-Cure (3M ESPE) and Clearfil SE Bond (Kuraray) were tested. Control samples were kept at 25 degrees C for 24 h. At each post-refrigeration time, the temperature was ...