Today, global energy supply, economy of productions and environment regulation controlled industry around the world. This defined a demand to save energy, reduce carbon emissions and protect the environment for the next generation. Due to that, engineers start to come up with tools and innovations to decrease the used energy. Pinch analysis is a tool used to design heat exchanger networks (HEN) with less energy usage. This paper will focus on pinch analysis and applying the second law of thermodynamic.
Pinch Analysis:
Pinch technology is a technology that provides a systematic methodology for energy saving in processes and plants. The methodology based on first low and second law of thermodynamic.
The pinch analysis uses Temperature-Enthalpy (T-H) diagram, composite curve. The temperature axis represents the available driving forces for heat transfer, while the enthalpy axis shows the supply and demand of heat. For processes with multiple cold streams, the individual process thermal duties of them are combined into a single cold composite curve. This carve is drawn on a Temperature-Enthalpy T-H diagram, which represents the enthalpy demand profile of the process. Similarly, all the thermal duties for hot streams is combined into a single hot composite curve, which represents the enthalpy availability profile of the process.
Next step is to define minimum approach temperature (∆Tmin) which is rule derived from the second law of thermodynamic. The optimum value of the Approach Temperature is a trade-off between cost savings from operating and capital cost of total area. The two curves, cold composite curve and hot composite curve, are moved horizontally and closely until the closest vertical approach between them is equal to the ...
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...te the minimum energy target at optimum minimum approached temperature used for the process. The same topology of the zero design will be kept but the new design will have a relax heat exchangers having the second minimum energy target.
Following these steps will help to design a heat exchanger network that will have a minimum energy quality and have the ability to easy retrofit.
Conclusion:
The second law of thermodynamics can be used as a tool to lower the cost of utilities in a heat exchanger network problem. Total low productions of entropy show a better use of the energy quality but with a high area cost. The provided steps helped to reduce the net cost of the utility now and for the future. The new design of the heat exchanger network opens the door for more aggressive energy saving and more reduction in greenhouse gas emissions in any industrial facility.
The MCE is typically in the range of (1-5) k/T (in terms of the adiabatic temperature change). This modest change in temperature is obviously not sufficient for applications such as domestic refrigeration etc. [24].
... the sun isn’t as high up in the sky. Large open spaces and a covered loft promote stack ventilation which also further increase the comfort zone. A mud room/hallway doubles as an airlock during extreme temperature months. The addition of active systems suffices for the rest of the heating load. On the roof positioned is a solar hot water panel which has access to solar gain. A small tankless electric water heater boosts stored hot water temperatures when needed. The ultimate goal is to simply reduce energy use by half of what the average household uses. The equipment chosen is an Eemax Electric Tankless Hot Water Heater. A solar hot water panel mounted on the dormer heats water through glycol exchange. A tankless electric hot water heater 1) boosts the solarheated stored water if it is below desired temps and 2) provides back up water heating during cloudy periods.
The membrane contactors can be used in different components of the absorption refrigeration systems such as absorber, desorber, solution heat exchanger etc. In this section absorption refrigeration cycle configurations of the investigations reviewed in the present work are discussed. The principle of operation and the use of membrane contactors in the desorber of absorption refrigeration systems can alter the configuration of the cycle. However, the use of membrane contactors in the absorber has no significant effect on the configuration of the cycle. Ali and Schwerdt (2009 and 2010), Ali (2010a or 2010b or both), Yu et al. (2012) and Isfahani et al. (2013) or Isfahani and Moghaddam (2013) [To check] used the plates-and-frames membrane module absorber with the same configuration of the conventional single-effect water-LiBr absorption cycle as shown in Figure 1 (a). Schaal et al. (2008) and Chen et al. (2006) used the conventional configuration of the single-effect ammonia-water absorption refrigeration cycle using hollow fiber membrane module absorber as shown in Figure 1 (b). The no-conventional cycle configurations used in the investigations reviewed in this work are herein discussed.
Refrigeration, the production of cold, is an essential practice for present-day living. It is used in a many place like the processing and preservation of food, conditioning of air for comfort, manufacture of chemicals and other materials, cooling of concrete, medical applications etc. Refrigeration is defined as the science of maintaining the temperature of a particular space lower than its surrounding space. Refrigeration and air conditioning involves various processes such as compression, expansion, cooling, heating, humidification, de-humidification, air purification, air distribution etc. In all these processes, there is an exchange of mass, momentum and energy. All these exchanges are subject to certain fundamental laws. Hence to understand and analyses the refrigeration and air conditioning systems, a basic knowledge of the laws of thermodynamics, fluid mechanics and heat transfer is essential.
Heat exchangers provide a rapid source of heat with the use of steam as opposed to alternative heating methods which are time consuming and costly. With cost and space being one of the constraints the concept of a Steels Mash aided in combining certain phases within the process. This helped reduce the number of tanks that where required along with the machinery.
Price, Darby. “Takaki Ch. 1, 4, 5” Engineering Building Room 343, San Jose. 24 February. 2014. Lecture.
...make the equations work and come up with an appropriate answer. From these equations, other ones can be created to solve many other problems on heat transfer. Anywhere that temperature exists, there is some sort of heat transfer happening. By predicting, analysing, and testing any equation in thermodynamics, we can learn how to conserve heat and energy for when we actually do need it.
Cengel, Y. A., & Boles, M. A. (2011). Thermodynamics: An engineering approach (7th ed.). New York, NY: McGraw-Hill.¬¬¬¬
Some of the fluid flow, heat flow and particle flow problems are the most complex problems. It is difficult to find the analytic solution of these problems due to their extra-ordinary complexity. Scientists and engineers are facing this problem from decades and then they turned to the numerical methods. By developing increasingly better numerical schemes, researchers have been able to solve increasingly more complex flow problems [11]. The heat diffusion equations are used to describe the flow of heat. In chapter 2 we use Nodal Integral Method to solve the heat diffusi...
There have been several studies on the exergy analysis of vapor compression refrigeration cycle. (T. Hari Prasad, 2009) Investigation of coefficient of performance, and determine the second law efficiency vapor compression refrigeration cycle using R-12 as refrigerant based on exergy analysis. (X.Xu, 1992) It studied of exergy analysis on vapor compression refrigeration using R12, R134a and R290 as refrigerants. (Miguel Padilla, 2010) It presented the exergy analysis of the impact of the direct replacement R12 with the R134A on the performance of vapor compression refrigeration system. (Rahul ukey, 2012) In this study, it studied different refrigerant that can optimized the performance of the vapor compression refrigeration system by using exergy analysis (Yaser Sahebi, 2010) It studied efficiency effect the on economical by using exergy analysis on heat pump. (J. U. Ahamed, 2011) It showed in study on prospect of hydrocarbon based on exergy analysis in vap...
Engineers’ main job is to solve problems and design things that make people’s life easier. One of the problems refrigeration engineers had to deal with at the beginning of the 20th century was how to ma...
... temperature of 112 0C also and a pressure 2.5 bar. Cooling water is used to condense the vapor exiting column. Remaining methane and hydrogen are separated in reflux drum where the vapor stream is combined with other gases streams. The overhead of first and second separator are combined to form fuel gas. The liquid stream exiting in the bottoms of the reflux drum is pumped at pressure of 3.3 bar for discharging pressure. The pump stream is separated in two streams. One stream is to feed to tray one of the column and the other one stream is cooled down to 38 0C in heat exchanger. Then, the cooled product stream is sent to storage.
In thermodynamics Refrigeration is the major application area, in which the heat is transferred from a lower temperature region to a higher temperature region. The devices which produce refrigeration are known as Refrigerators and the cycle on which it operates are called refrigeration cycles. Vapour compression refrigeration cycle is the most regularly used refrigeration cycle in which the refrigerant is alternately vaporized and condensed and in the vapor phase it is compressed. Gas refrigeration cycle is the well-known refrigeration cycle in which cycle refrigerant remains in the gaseous phase throughout the cycle. Cascade refrigeration are the other refrigeration cycles discussed in this chapter; absorption refrigeration is the one more refrigeration cycle which is used where the refrigerant is dissolved in liquid before it is compressed. One more refrigeration in which refrigeration is produced by passing the electric current through two dissimilar materials is called as the thermoelectric refrigeration.
turbine via interceptor valves and control valves and after expanding enters the L.P. turbine stage via 2 numbers of cross over pipes. In the L.P. stage the steam expands in axially opposite direction to counteract the trust and enters the condenser placed directly below the L.P. turbine. The cooling water flowing throughout the condenser tubes condenses the steam and the condensate collected in the hot well of the condenser. The condensate collected is pumped by means of 3*50% duty condensate pumps through L.P. heaters to deaerator from where the boiler feed pump delivers the water to boiler through H.P. heaters thus forming a closed
The manufacturing process has provided related index number which indicates the relativity of environmental impact to the respect components. Based on such specific output, conclusion and suggestion can be drawn to recognize which is the most significance factor can be optimized. From the figure, the outer pot, power cord and heat plate occupied large ratio of optimising. Based on such specific analysis, designers may conveniently recognise which subassembly is the most significant impact factor so that could make an improvement when design the product.