This paper deals with the investigation of substitutes for R-22 and their heat transfer behaviour in a plate-type evaporator with a falling water film as heat source. Alternatives investigated were R-134a and two new refrigerant mixtures. Measurements on a 3m x 0,5m plate showed a superior performance ofR-134a compared to R-22 and mixtures at equal test conditions and a distinct difference betw...

This study investigated experimentally and theoretically, how condensate and initial formation of a thin frost layer on the surface of the evaporator affects the evaporator performance of room air-conditioners compared to dry coil conditions. The theoretically obtained results were validated with the measured values in both wet and initial frost formation conditions and a good correlation was f...

Given the rapid progress in the electronics industry, the thermal management of electronics components becomes an important and serious issue. Natural and forced cooling are often deficient. One possibility for heat dissipation for high heat flux is using loop heat pipe. A loop heat pipe (LHP) is a two-phase device with extremely high effective thermal conductivity that utilizes pressure differ...

Multiple-evaporator/vapor compression cooling systems are used for air conditioning in multi-zone buildings with a refrigerant supplied to each individual zone-evaporator from a central compressor/condenser unit. Such systems, incorporating controlled electronic expansion valves associated to each evaporator and a variable-speed compressor, allow the overall system to be able to operate in diff...

The main purpose of this research is to analyze the performance of an evaporator for the organic Rankine cycle (ORC) system and discuss the influence of the evaporator on the operating characteristics of diesel engine. A simulation model of fin-and-tube evaporator of the ORC system is established by using Fluent software. Then, the flow and heat transfer characteristics of the exhaust at the ev...

Floating gate memory devices were fabricated using well-ordered gold nanoparticle/block copolymer hybrid films as the charge trapping layers, SiO(2) as the dielectric layer, and poly(3-hexylthiophene) as the semiconductor layer. The charge trapping layer was prepared via self-assembly. The addition of Au nanoparticles that selectively hydrogen bond with pyridine in a poly(styrene-b-2-vinyl pyri...

The paper analyzes the various factors that cause failure of refrigerator evaporator. The refrigerator evaporator failure spectrum is constructed through qualitative analysis of the fault tree system after building a corresponding fault tree system. There is an analysis procedure of fault tree system based on computer aided fault tree analysis system (CAFTA).

The cold roll bonding of Al on AISI 304L stainless steel was carried out to fabricate the Al/304L/Al clad sheet composites. The maximum bond strength of 20 N/mm was acquired just by 38% reduction, for which the tearing of the aluminum sheet occurred during the peeling test. The microstructural evolution during subsequent postannealing heat treatment was systematically studied based on the impur...

Microchannel heat exchangers (MCHX) are being increasingly applied in heat pumps because of their compactness, significant charge reduction, lower refrigerant pressure drop and lower air-side fan power consumption compared to traditional round tube-plate fin (RTPF) heat exchangers. Using a microchannel condenser as well as evaporator in a heat pump system also offers significant potential for c...