Buildings have a major contribution to the global energy consumption. Heating, ventilating and air conditioning systems (HVAC) are responsible for most of the energy use in buildings. Thus, clean and sustainable alternatives such as free cooling of buildings have recently gained much attention as means to reduce the operation hours and capacity of the conventional cooling and heating systems. The free cooling could be provided by collecting the natural cold energy during night time in appropriate thermal storage form and this could be retrieved when needed. Phase change materials are exploited by a number of investigators as a storage medium in free cooling applications, as these substances possess high energy densities, and absorb and release heat at a narrow temperature range, hence, the comfort temperature can be maintained day and night. The objectives of this article are to provide a comprehensive review on recent development on free cooling technologies incorporating latent heat storage and to shit lights on the most significant parameters affecting the performance of these materials in free cooling strategy. The outcomes of this review would be helpful in providing clear insight information on potential improvements that can be applied to the storage materials. All the reviewed studies demonstrated that the night cooling strategy using PCMs has the capacity to maintain the indoor temperature well within the comfort zone whilst providing a considerable reduction in cooling loads in all considered climates.

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Critical review of latent heat storage systems for free cooling in buildings

The plate heat exchangers (PHE) with small size but large efficiency are compact types of heat exchangers formed by corrugated thin pressed plates, operating at higher pressures when compared to most other traditional exchangers. This paper aims to analyze heat transfer characteristics in the PHE experimentally and numerically.,Computational fluid dynamics analysis has been used to simulate the problem by using the ANSYS fluent 16 software. Also, the effect of using TiO2/water nanofluid as working fluid was investigated. TiO2/water nanofluid had 2% (Wt/Wt) nanoparticle content. To improve solubility of the TiO2 nanoparticles, Triton X-100 was added to the mixture. The results have been achieved in different working condition with changes in fluid flow rate and its temperature.,The obtained results showed that using TiO2/water nanofluid improved the overall heat transfer coefficient averagely as 6%, whereas maximum improvement in overall heat transfer coefficient was 10%. Also, theoretical and experimental results are in line with each other.,The most important feature which separates the present study from the literature is that nanofluid is prepared by using TiO2 nanoparticles in optimum size and mixing ratio with surfactant usage to prevent sedimentation and flocculation problems. This process also prevents particle accumulation that may occur inside the PHE. The main aim of the present study is to predict heat transfer characteristics of nanofluids in a plate heat exchanger. Therefore, it will be possible to analyze thermal performance of the nanofluids without any experiment.

Simulation and experimental analysis of heat transfer characteristics in the plate type heat exchangers using TiO2/water nanofluid

Effect of chevron angle and surface roughness on thermal performance of single-phase water flow inside a plate heat exchanger

The increasing growth of energy demand leads to issues associated with energy demand reduction and propose new energy efficient solutions. Heat recovery consists the most promising solution especially in regions where renewable energy resources are not available. That is why the domain of heat recovery has shown a tremendous improvement during the recent years. On the other hand, few works have been dedicated to heat recovery from exhaust gas. This paper presents a review on heat recovery from exhaust gas. The authors propose to classify exhaust gas heat recovery systems within three different classifications that are exhaust gas temperature, utilized equipment and recovery purposes.

Short review on heat recovery from exhaust gas

Passive cooling systems in livestock buildings towards energy saving: A critical review

Plate Heat Exchangers – Flow Analysis through Mini Channels

In nowadays, the Phase Change Material (PCM) is a viable alternative for reducing the energy consumption and for increase the thermal comfort in buildings. The use of PCM in building applications provides the potential to increase the indoor thermal comfort for occupants due to the reduced indoor temperature fluctuations and lower global energy consumption. The possibility to incorporate the PCM into the material of construction for cooling and heating the buildings gained the interest of researchers from all the world because the PCM have a high heat of fusion, meaning it is capable to storing and release large amounts of energy in the form of heat during its melting and solidifying process at a specific temperature.

/pdf/review-on-phase-change-materials-for-building-applications-4ln3rocctp.pdf

Review on phase change materials for building applications

Dynamic absorbers are used to reduce torsional vibrations. This paper studies the effect of a dynamic absorber attached to a mechanical system formed of three reduced masses which are acted on by one, two or three order x harmonics of a disruptive force.

/pdf/contributions-to-the-study-of-dynamic-absorbers-a-case-study-35tb6vl2v0.pdf

Contributions to the Study of Dynamic Absorbers, a Case Study

Auto Radiators – Study Regarding Air Flow along the Channels

The study presents further Computational Fluid Dynamics (CFD) numerical analysis for two models of plate heat exchangers. Comparatively was studied the influence of geometric characteristics of plates on the intensification process of heat exchange. For this purpose, it was examined the distribution of velocity and temperatures fields on active plate height. Heat transfer characteristics were analysed through the variation of mass flow on the primary heat agent.

Angela Plesa

Papers

Plate Heat Exchangers – Flow Analysis through Mini Channels

Review on phase change materials for building applications

Contributions to the Study of Dynamic Absorbers, a Case Study

Auto Radiators – Study Regarding Air Flow along the Channels

The effect of plate heat exchanger's geometry on heat transfer