A nanofluid is mixture of nano sized particles and a base fluid. This paper investigates by using laboratory based double pipe heat exchanger model, the performance of nanofluid containing about 48.46nm  particle size nanoparticles (ZnO) without or with addition of nonionic surfactant Rokanol K7 (500ppm) into the base fluid double distilled water to prepared three different concentrations 1.0%,...

This paper presents an experimental investigation of convective heat transfer coefficient for nanofluids using spiral pipe heat exchanger. The aim of this study is to investigate experimentally flow and convective heat transfer characteristics of water-based nanofluids flowing through a spiral pipe. The test section consist of spiral pipe with ratio pitch per diameter is 7.0 and mean hydraulic ...

In this paper, the heat pipe heat exchanger (HPHE) is considered and computational fluid dynamics (CFD) is used to analyze its evaporator’s performance and based on it, will be try to increase the thermal efficiency and to optimize the distribution of fluid flow in this type of heat exchangers. The CFD principles which are made use in this article are effective and appropriate methods that usin...

abstract: in this study, al 2 o 3 /eg and tio 2 /eg nanofluids as coolants have been used in the double-tube heat exchanger. the hot solvent inlet heat exchanger must be cooled down with a specified amount. we can use nanofluids as coolants in the heat exchanger for optimization of the heat transfer area. therefore, the efficacy of nanofluids as coolants is verified. furthermore, flow rate of c...

Research results have identified the use of heat pipe heat exchangers (HPHXs) for heat recovery as a way to reduce the pre-cooling and re-heating energy. This paper suggests decoupling dehumidification from cooling to reduce energy consumption. The feasible usage and the energy saving potential of heat pipe heat exchanger at the air handler dedicated in accomplishing this objective is investiga...

Fin-tube heat exchangers are widely used in air-conditioners and heat pumps, which are constructed with a lot of tubes. Refrigerant circuit of heat exchanger with numerous pipe can be constructed by many methods. Refrigerant circuit design is usually determined designer’s experience and case by case test without guides. The number of path affects largely on heat exchanger performance. In this p...

In this study, in order to increase the heat transfer rate in concentric double-pipe heat exchangers by an active method, a rotating ball valve was mounted downstream of the outer pipe end and used as a pulse generator. In the experimental set-up, hot water (40-70 °C) was passed through the inner pipe with fixed mass flow rate (Reynolds number ≈ 10,200) while cold water was passed through the a...

2014 The present paper reviews the problem of short term thermal energy storage for low temperature solar heating applications. The techniques of sensible and latent heat storage are discussed, with particular emphasis on the latter. Requirements for hot water storage subsystems are provided and the importance of stratification in hot water storage tanks is described. Concerning latent heat sto...