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Boilers and Fired Systems
Published in Stephen A. Roosa, Steve Doty, Wayne C. Turner, Energy Management Handbook, 2020
In today’s environment of ever-increasing fuel costs, the return and utilization of the heat available in clean steam condensate streams can be a practical and economical energy conservation opportunity. Refer to Chapter 6 for a comprehensive discussion of condensate return. The information below summarizes the benefits and major considerations pertinent to optimum steam generator operations. Recognized benefits of return condensate include: Reduction in steam power plant raw-water makeup and associated treatment costs.Reduction in boiler blowdown requirements, resulting in direct fuel savings (refer to section on boiler blowdown).Reduced steam required for boiler feedwater deaer-ation.Raw-water and boiler-water chemical cost reduction.Opportunities for increased useful work output without additional energy input.Reduces objectionable environmental discharges from contaminated streams.
Nonrenewable Energy Sources
Published in John C. Ayers, Sustainability, 2017
Efficiency is the ratio of the work output to the energy input; sometimes power is used in place of energy because power is the rate of energy use. If we express efficiency as useful power output divided by total power input, values range from zero (completely inefficient) to one, or as a percentage from 0% to 100%. In cases where the numerator and denominator have different units of measure, efficiency is not unitless. For example, fuel efficiency measures the distance traveled (miles) per amount of fossil fuel (per gallon of gasoline). Lighting efficiency expresses the amount of light (lumens) per quantity of power (watts). Efficient systems use most input energy to do useful work; inefficient systems use much of the input energy to produce wasted heat or noise.
Overview and introduction
Published in Tom Denton, Automobile Mechanical and Electrical Systems, 2018
All other machines are combinations of these three. This is a good way of making any complicated machine easier to understand. The main features of a machine are: mechanical advantage, which is the ratio of load to effort (think of a car jack)velocity ratio, which is the velocity input compared to the velocity output (think of a car gear box)efficiency, which is the work output divided by the work input as a percentage.
Solar assisted heat engine systems: multi-objective optimisation and decision making
Published in International Journal of Ambient Energy, 2022
R. Venkata Rao, Hameer Singh Keesari
Solar dish heat engine system extracts the energy from sunrays and converts that into useful energy. A solar dish heat engine system typically consists of a heat engine and solar concentrator. Solar concentrator reflects the sunlight at the focal point of the concentrator where the receiver is placed. The hot end region of the heat engine is placed at the receiver. The receiver then transmits the collected heat energy to the working fluid of the heat engine. The work output from the heat engine is then utilised to drive a generator that produces electric power. The heat engine of a solar dish system plays a vital role in the conversion of solar energy into useful energy. Hence, in this work, two configurations of solar systems which work on different thermodynamic cycles are studied. First solar system configuration heat engine works on a Carnot-like cycle and the latter works on the Brayton cycle. The following subsections present the thermodynamic analysis of these solar system configurations.
Parametric optimisation of exergy destruction in small DI diesel engine fuelled with neem biodiesel using the Taguchi method
Published in International Journal of Ambient Energy, 2020
Veena Chaudhary, R. P. Gakkhar
Similar to energy analysis, same assumptions were made for exergy analysis; the complete engine was considered to be an open system as shown in Figure 2, operating at steady state. The exergy balance under steady-state conditions, for the control volume can be stated as In an IC engine, the exergy input is in the form of chemical exergy of the fuel. This input exergy is distributed in the following: (i) Work output or shaft work exergy , (ii) Exergy associated to cooling water , (iii) Exergy associated to the exhaust gases , (iv) Exergy destructions , (v) Exergy associated to unaccounted heat losses .
Thermodynamic and multi-objective optimisation of solar-driven Organic Rankine Cycle using zeotropic mixtures
Published in International Journal of Ambient Energy, 2019
Deepak Tiwari, Ahmad Faizan Sherwani, Akhilesh Arora
Conservation of mass (Hassoun and Dincer 2015): Conservation of energy (Hassoun and Dincer 2015; Sadeghi et al. 2016) Balance entropy (Hassoun and Dincer 2015) Exergy balance (Hassoun and Dincer 2015) Turbine work output where Specific volume flow ratio Pump work The expression for enthalpy at the exit of pump. Heat supplied in the evaporator without IHE Heat supplied in the evaporator with IHE