In a cylindrical scraped heat exchanger crystallizer geometry the flow field influence on the local heat transfer distribution on an evenly cooled scraped heat exchanger surface has been studied by direct measurements of the heat exchanger surface temperature and the fluid velocity field inside the crystallizer. Liquid Crystal Thermometry revealed that the local heat transfer is higher in the m...

This paper presents the heat transfer coefficients and the pressure drop measured during HC-600a (Isobutane) condensation inside a brazed plate heat exchanger: the effects of saturation temperature, refrigerant mass flux and vapour super-heating are investigated. The heat transfer coefficients show weak sensitivity to saturation temperature and great sensitivity to refrigerant mass flux. At low...

The natural convection flow over a surface embedded in saturated porous media is encountered in many engineering problems such as the design of pebble-bed nuclear reactors, ceramic processing, crude oil drilling, geothermal energy conversion, use of fibrous material in the thermal insulation of buildings, catalytic reactors and compact heat exchangers, heat transfer from storage of agricultural...

the performance of a γ-al 2 o 3 /n-decane nanofluid shell-and-tube heat exchanger in a biomass heating plant is analyzed to specify the optimum condition based on the maximum heat transfer rate and performance index for wide range of nanoparticle volume fraction (0–7%). compared with pure          n-decane, the obtained results in this research show that by using γ-al 2 o 3 /n-decane nanofluid ...

heat exchangers are the critical components of refrigeration and liquefaction processes. selection of appropriate operational conditions for cryogenic recuperative heat exchanger and expansion valve operating in joule-thomson cooling system results in improving the performance and efficiency. in the current study, a straightforward procedure is introduced to design an efficient joule-thomson co...

No portion of this publication may be altered in any form without prior written consent from the U.S. Department of Energy and the authoring national laboratory. both residential and commercial/institutional buildings. However, GHPs often have higher first costs than conventional systems making short-term economics unattractive. This disadvantage can be magnified in commercial buildings, many o...

Experiments were performed to study the effects of introducing vapor into a dewar where a coaxial pulse tube refrigerator was used as a liquefier in the neck of the dewar. We were concerned about how the introduction of vapor might impact the refrigeration load as the vapor barrier in the neck of the dewar is disturbed. Three experiments were performed where the input power to the cooler was he...

Average Nusselt numbers were measured for R22, R290, R290/600a, and R32/152a undergoing evaporation and condensation in a brazed plate heat exchanger. The refrigerants experienced wavy, stratified flow at low heat and mass fluxes, 1.3 kW/m2 to 8.3 kW/m2 and 1.6 kg/m2 s to 19 kg/m 2 s, respectively. Heat transfer correlations from the literature for in-tube and channel flow of refrigerants with ...

Introduction Normal Mechanisms of Heat and Moisture Exchange in the Respiratory Tract High-Flow Humidifiers Pass-over Humidifiers Wick Humidifiers Bubble Humidifiers Artificial Noses Moisture Output Resistance Dead Space Additives Cost Choosing an Artificial Nose Active Hygroscopic Heat and Moisture Exchangers HME-Booster Use of Humidification Devices During Mechanical Ventilation Use of Heated...