In air-cooling applications with frost production, heat exchanger performance is often air-side limited, because the two-phase flow of the refrigerant provides excellent heat transfer coefficients, and because designers typically use a large air-side fin spacing for frost tolerance. The large fin spacing prolongs operation of the heat exchanger by mitigating the effect of the accumulating frost...

Object-oriented heat-exchanger models were developed to simulate the dynamic thermal effects of dynamic changes in fluid composition and thus of fluid properties in a type of liquid typical for food products. The models were written in the object-oriented language Modelica as objects in a library structure being developed to simulate complex liquid food process lines and their control systems. ...

this study represents effect of four variables in performance of a heat-pump in two cities of tehran and rasht. a computer program has been developed, simulating a certain heat pump acting in different environments with different refrigerants in heating season. the analysis is based on a homogeneous model. effect of different refrigerants, depth of the buried heat exchangers and moisture conten...

in this paper, overall heat transfer coefficient and friction factor of water based γ-al2o3 nanofluid in a double tube counter flow heat exchanger have been measured experimentally under turbulent flow condition. for better dispersion of γ-al2o3 nanoparticles in distilled water, magnetic stirrer and ultrasonic vibrator (with a power of 240 kw and frequency of 35 khz) were implemented. the stabi...

nanofluid is a new class of heat transfer fluids engineered by dispersing metallic or non-metallic nanoparticles with a typical size of less than 100 nm in the conventional heat transfer fluids.this article aims to investigate the overall and convection heat transfer coefficient and nusselt number of al2o3-water nanofluid flowing in a horizontal double pipe heat exchanger under turbulent flow (...