Standard Specification for Heat Transfer Fluids (HTF) for Heating and Air Conditioning (HVAC) Systems

2016 ◽  
Author(s):  
Keyword(s):  
Heat Transfer ◽  
Air Conditioning ◽  
Hvac Systems ◽  
Standard Specification ◽  
Heat Transfer Fluids

scholarly journals A Multi-Timescale Bilinear Model for Optimization and Control of HVAC Systems with Consistency

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 400 ◽  
Author(s):  
Zelin Nie ◽  
Feng Gao ◽  
Chao-Bo Yan
Keyword(s):  
Optimization Model ◽  
Air Conditioning ◽  
State Of The Art ◽  
Hvac Systems ◽  
Practical Significance ◽  
Hvac System ◽  
Bilinear Model ◽  
Optimization And Control ◽  
And Control ◽  
Slow Timescale

Reducing the energy consumption of the heating, ventilation, and air conditioning (HVAC) systems while ensuring users’ comfort is of both academic and practical significance. However, the-state-of-the-art of the optimization model of the HVAC system is that either the thermal dynamic model is simplified as a linear model, or the optimization model of the HVAC system is single-timescale, which leads to heavy computation burden. To balance the practicality and the overhead of computation, in this paper, a multi-timescale bilinear model of HVAC systems is proposed. To guarantee the consistency of models in different timescales, the fast timescale model is built first with a bilinear form, and then the slow timescale model is induced from the fast one, specifically, with a bilinear-like form. After a simplified replacement made for the bilinear-like part, this problem can be solved by a convexification method. Extensive numerical experiments have been conducted to validate the effectiveness of this model.

New Thermal Energy Storage Materials From Industrial Wastes: Compatibility of Steel Slag With the Most Common Heat Transfer Fluids

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Iñigo Ortega-Fernández ◽  
Javier Rodríguez-Aseguinolaza ◽  
Antoni Gil ◽  
Abdessamad Faik ◽  
Bruno D’Aguanno
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Steel Slag ◽  
Industrial Wastes ◽  
Energy Storage Materials ◽  
Iron And Steel ◽  
Heat Transfer Fluids ◽  
Wide Range

Slag is one of the main waste materials of the iron and steel manufacturing. Every year about 20 × 106 tons of slag are generated in the U.S. and 43.5 × 106 tons in Europe. The valorization of this by-product as heat storage material in thermal energy storage (TES) systems has numerous advantages which include the possibility to extend the working temperature range up to 1000 °C, the reduction of the system cost, and at the same time, the decrease of the quantity of waste in the iron and steel industry. In this paper, two different electric arc furnace (EAF) slags from two companies located in the Basque Country (Spain) are studied. Their thermal stability and compatibility in direct contact with the most common heat transfer fluids (HTFs) used in the concentrated solar power (CSP) plants are analyzed. The experiments have been designed in order to cover a wide range of temperature up to the maximum operation temperature of 1000 °C corresponding to the future generation of CSP plants. In particular, three different fluids have been studied: synthetic oil (Syltherm 800®) at 400 °C, molten salt (Solar Salt) at 500 °C, and air at 1000 °C. In addition, a complete characterization of the studied slags and fluids used in the experiments is presented showing the behavior of these materials after 500 hr laboratory-tests.

Use of metallic nanoparticles to improve the thermophysical properties of organic heat transfer fluids used in concentrated solar power

Solar Energy ◽  
2014 ◽  
Vol 105 ◽  
pp. 468-478 ◽  
Author(s):  
Dileep Singh ◽  
Elena V. Timofeeva ◽  
Michael R. Moravek ◽  
Sreeram Cingarapu ◽  
Wenhua Yu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermophysical Properties ◽  
Metallic Nanoparticles ◽  
Solar Power ◽  
Concentrated Solar Power ◽  
Heat Transfer Fluids

Settling Characteristics of Alumina Nanoparticles in Ethanol-Water Mixtures

2013 ◽  
Vol 372 ◽  
pp. 143-148 ◽  
Author(s):  
Suhaib Umer Ilyas ◽  
Rajashekhar Pendyala ◽  
Narahari Marneni
Keyword(s):  
Heat Transfer ◽  
Base Fluid ◽  
Particle Diameter ◽  
Alumina Nanoparticles ◽  
Visualization Method ◽  
Nanoparticle Concentration ◽  
Enhanced Heat Transfer ◽  
Heat Transfer Fluids ◽  
Sedimentation Behavior ◽  
Settling Characteristics

Nanofluids are considered as promising heat transfer fluids due to enhanced heat transfer ability as compared to the base fluid alone. Knowledge of settling characteristics of nanofluids has great importance towards stability of nanosuspensions. Sedimentation behavior of Alumina nanoparticles due to gravity has been investigated using different proportions of ethanol-water binary mixtures. Nanoparticles of 40 nm and 50 nm are used in this investigation at 23°C. Sediment height with respect to time is measured by visualization method in batch sedimentation. The effect of sonication on the sedimentation behavior is also studied using ultrasonic agitator. The effect of particle diameter, nanoparticle concentration and ethanol-water proportion on sedimentation behavior of nanofluids has been investigated and discussed.

A Brief Review on Thermal Behaviour of PANI as Additive in Heat Transfer Fluid

2021 ◽  
Vol 02 (01) ◽  
Author(s):  
A.G.N. Sofiah ◽  
◽  
M. Samykano ◽  
S. Shahabuddin ◽  
K. Kadirgama ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Properties ◽  
Conducting Polymers ◽  
Volume Fraction ◽  
Corrosion Property ◽  
Environmental Stability ◽  
Heat Transfer Fluid ◽  
Thermal Engineering ◽  
Engineering System ◽  
Heat Transfer Fluids

Since a decade ago, investigation on nanofluids has grown significantly owing to its enhanced thermal properties compared to conventional heat transfer fluids. This engineered nanofluid has been widely used in the thermal engineering system to improve their energy consumption by improving the thermal efficiency of the system. The addition of nano-size particles as additives dispersed in the base fluids proved to significantly either improve or diminish the behaviour of the base fluids. The behaviour of the base fluid highly depends on the properties of the additives material, such as morphology, size, and volume fraction. Among the variety of nanoparticles studied, the conducting polymers have been subject of high interest due to its high environmental stability, good electrical conductivity, antimicrobial, anti-corrosion property and significantly cheap compared to other nanoparticles. As such, the main objective of the present review is to provide an overview of the work performed on thermal properties performance of conducting polymers based nanofluids.

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