The Exergy Loss Distribution and the Heat Transfer Capability in Subcritical Organic Rankine Cycle

One of the key challenges on the area of energy engineering is the system development for increasing the efficiency of primary energy conversion and use. An effective and important measure suitable for improving efficiencies of existing applications and allowing the extraction of energy from previously unsuitable sources is the Organic Rankine Cycle. Applications based on this cycle allow the use of low temperature energy sources such as waste heat from industrial applications, geothermal sources, biomass, fired power plants and micro combined heat and power systems.Working fluid selection is a major step in designing heat recovery systems based on the Organic Rankine Cycle. Within the framework of the previous original study a special tool has been elaborated in order to compare the influence of different working fluids on performance of an ORC heat recovery power plant installation. A database of a number of organic fluids has been developed. The elaborated tool should create a support by choosing an optimal working fluid for special applications and become a part of a bigger optimization procedure by different frame conditions. The main sorting criterion for the fluids is the system efficiency (resulting from the thermo-physical characteristics) and beyond that the date base contains additional information and criteria, which have to be taken into account, like environmental characteristics for safety and practical considerations.The presented work focuses on the calculation and optimization procedure related to the coupling heat source – ORC cycle. This interface is (or can be) a big source of energy but especially exergy losses. That is why the optimization of the heat transfer between the heat source and the process is (besides the ORC efficiency) of essential importance for the total system efficiency.Within the presented work the general calculation approach and some representative calculation results have been given. This procedure is a part of a complex procedure and program for Working Fluid Selection for Organic Rankine Cycle Applied to Heat Recovery Systems.

Download Full-text

Effect of heat-transfer capability on micropore structure of freeze-drying alginate scaffold

Materials Science and Engineering C ◽

10.1016/j.msec.2018.08.055 ◽

2018 ◽

Vol 93 ◽

pp. 944-949 ◽

Cited By ~ 4

Author(s):

Conger Wang ◽

Wei Jiang ◽

Wenqian Zuo ◽

Guangting Han ◽

Yuanming Zhang

Keyword(s):

Heat Transfer ◽

Freeze Drying ◽

Micropore Structure ◽

Transfer Capability ◽

Heat Transfer Capability ◽

Alginate Scaffold

Download Full-text

Experimental Evaluation on the Effect of Nanofluids Physical Properties With Different Concentrations on Grinding Temperature

Enhanced Heat Transfer Mechanism of Nanofluid MQL Cooling Grinding - Advances in Chemical and Materials Engineering ◽

10.4018/978-1-7998-1546-4.ch009 ◽

2020 ◽

pp. 203-225

Keyword(s):

Heat Transfer ◽

Base Fluid ◽

Experimental Studies ◽

Grinding Force ◽

Grinding Temperature ◽

Low Carbon ◽

Heat Transfer Mechanism ◽

Transfer Capability ◽

Heat Transfer Capability ◽

Technical Guidance

This chapter is proposed to solve the insufficient MQL cooling and heat transfer capability based on the heat transfer enhancement theory of solid. Adding nanoparticles into the base fluid can significantly elevate heat conductivity coefficient of the base fluid and enhance convective heat transfer capability of the grinding area. Researchers have carried out numerous experimental studies on nanofluids with different concentrations. However, the scientific nature of MQL cooling has not been explained. Degradable, nontoxic, low-carbon, and environmentally friendly green grinding fluid, palm oil taken as the base fluid, grinding force, grinding temperature and proportionality coefficient of energy transferred to workpiece of nanofluids with different volume fractions, are investigated in this chapter. Based on the analysis of the influence of physical characteristics of nanofluids on experimental results, cooling and heat transfer mechanism of NMQL grinding is studied. The experimental study can provide a certain technical guidance for industrial machining.

Download Full-text