A5033097802- Heat Transfer and Boiling Studies
- Heat Transfer and Optimization
- Refrigeration and Air Conditioning Technologies
- Phase Change Materials Research
- Solar Thermal and Photovoltaic Systems
- Heat and Mass Transfer in Porous Media
- Fluid Dynamics and Heat Transfer
- Spacecraft and Cryogenic Technologies
- Nanofluid Flow and Heat Transfer
- Electrohydrodynamics and Fluid Dynamics
- Fluid Dynamics and Thin Films
- Aerosol Filtration and Electrostatic Precipitation
- Adsorption and Cooling Systems
- Pickering emulsions and particle stabilization
- Nuclear Engineering Thermal-Hydraulics
- Solar Energy Systems and Technologies
- Fluid Dynamics and Mixing
- Advanced Thermodynamic Systems and Engines
- nanoparticles nucleation surface interactions
- Fusion materials and technologies
- Nuclear Materials and Properties
- Solar-Powered Water Purification Methods
- Building Energy and Comfort Optimization
- Heat Transfer Mechanisms
- Heat transfer and supercritical fluids
University of Padua
2014-2024
This paper proposes a new method to determine the condensation heat transfer coefficient of fluids flowing into horizontal smooth tubes with internal diameters D > 3 mm. The has been drawn up as simply possible and is ready use in exchanger modeling design applications. It also suitable work very well old used refrigeration, air conditioning, pump industries. Particular attention given accuracy: it tested over wide updated experimental database comes from many different independent...
The paper presents a new predicting model to compute the heat transfer coefficient and pressure drop during condensation inside smooth tubes when operating with pure or blended halogenated refrigerants, including high-pressure HFC fluids, for which existing methods are inadequate. suggested is based on predictive study of flow patterns occurring process. Predictions from this procedure compared both authors' experimental data wide bank independent authors; excellent agreement demonstrated in...
The present paper reviews published experimental work focusing on condensation flow regimes, heat transfer, and pressure drop in minichannels. New data are available with high (R410A), medium (R134a), low (R236ea) refrigerants minichannels of different cross-section geometries hydraulic diameters ranging from 0.4 to 3 mm. Because the influence regimes transfer drop, a literature review is presented discuss transitions. frictional gradients coefficients compared semi-empirical theoretical...
Abstract In this paper, the experimental heat transfer coefficients measured during condensation of R134a and R410A inside multiport minichannels are presented. The frictional pressure gradient was also adiabatic two-phase flow. need for research on comes from wide use those channels in automotive air-conditioners. perspective adoption similar residential air conditioning applications calls new high refrigerants, such as R410A. Experimental data compared against models to show accuracy...
In the scientific and industrial community, interest on Latent Thermal Energy Storages (LTESs) is continuously increasing. These components can be easily coupled with intermittent renewable energy sources heat that undergo to cycling operations. Phase Change Materials (PCMs) are considered convenient reliable media used in LTES. Nevertheless, their low thermal conductivity remains greatest hindrance still limits technological application. The present work aims at increasing effective of a...
A new computational procedure for heat transfer coefficient and pressure drop during condensation of pure refrigerants refrigerant mixtures inside enhanced tubes is presented. modified form the Cavallini Zecchin equation (Cavallini Zecchin, 1971, 1974) smooth tube has been implemented low-fin, micro-fin cross-grooved tubes: comparison with a set around 300 experimental data points, including both refrigerants, azeotropic zeotropic mixtures, shows an absolute mean deviation 15%. Two...
In this paper, experimental data pertinent to deionized water pool boiling across 10 mm thick aluminum foams are presented. Two foam samples with different pore densities, 5 and pores per inch, yet an identical mean porosity of 0.92 tested. Compared a heated flat plate, the same base size, offer higher heat transfer area albeit at induced bubble escaping resistance. The tradeoff between these two effects is investigated. Through use high-speed camera recording, generation, trajectory growth...
The refrigerant charge minimization in refrigerating and air-conditioning systems represents a challenging issue due to the new environmental national international regulations. use of smaller smooth tubes, such as with outer diameter around 5 mm, is becoming more common many applications. More recently, microfin tubes have also started be reduced size cope continuously increasing demand new, efficient, compact heat exchangers for refrigeration equipment. This work investigates performance...
This paper is focused on modularized concrete sensible thermal energy storage systems with oil as heat transfer fluid; the have been conceived to be integrated into a concentrated solar power plant. work mainly effect of modules' arrangement overall performance system. Series and parallel arrangements are investigated, determine most performant solutions in terms exchanged function main operating conditions: mass flow rate pressure drop, both heating cooling phase. Two different boundary...