Heat Recovery with the Turbo Steamer - Case Study Example

Design of heat recovery turbo steamer for Toyota land-cruiser V8 Your name Name of Assignment 16th April, 2015 Introduction The main aim of this project is to design turbo steamer for Toyota land-cruiser V8 which will help in each recovery from the engine of the car. The heat that is produced by engine recovered utilized and minimize the amount of pollutants being released to the atmosphere and also reduce the dependency on the conventional energy resources. The quest for increasing the efficiency, mileage, reliability and sustainability of automobiles has forced us to focus on the energy flow in a vehicle and the places at which it can be utilized. The above systems mentioned will help the land-cruiser V8 engine make use of waste heat efficiently. This will also make the land cruiser environmental friendly as well as increase the benefits of land cruiser(Jason, 2011). For any heat recovery system to be successful in compatibility with the turbo steamer for Toyota land-cruiser V8 where it will used, the design and modeling takes into account that heat recovery system that can withstand various environmental during it use (Endo, 2007). It has been modeled using SolidWorks software focusing on appearance. The purpose was to make sure the turbo steamer for Toyota land-cruiser V8 is able to perform their duties properly. If there is a fault in the system, heat may not recovered. Consideration of sustainability (materials choice / energy / end of life) Sustainability: In very simple words sustainability can be defined as the accurate balance between environmental care, social responsibility and economic progress. In recent times due to increase in the effect of global warming the emission norms are getting stricter to make the automobiles eco-friendly. There has also been attempt to increase the efficiency while improving the drivability of the vehicle for maintaining the balance between environmental care and economic progress. The project would also aim at increasing the sustainability of automobiles by developing a product which would increase the efficiency while reducing the fuel consumption of the vehicle (Heisler, 1999). Material selection :- In order to have a successive turbo Steamer, proper choice of materials need to be selected. The materials selected should be environmental friendly as well as being cost effective. The impact of heat released from land cruiser V8 engine can be environmental friendly due to the release to the environment. Therefore, designing turbo steamer engine will be cost effective and necessary for the company. The materials that will be used to design the system are liquor, BiTe (bismuthtellluride), CeFeSb (skutterudite), ZnBe (Zinc-beryllium), SiGe (silicon-germanium), SnTe (tintel-Uride). The materials that are being used will be analyzed using Where K is Thermal conductivity, S is thermopower, T is the absolute temperature and p is electric resistance(Jason, 2011). This materials can be can be manipulated with ease, a range of materials have been settled upon when it comes to targeted properties for heat recovery system manufacture. The properties that are of interest for this application mainly are absolute temperature, Electric resistance, electric resistance and toughness against possible operational fractures. Unlike multiphase materials such as metals, the operating mechanisms of alloys properties are unique. The mechanical properties of this material and its respective constituents are very important especially for this application. The thermal properties have been noted for their ease of manipulation through the heat treatment procedures. Any procedure involved in the processing of alloys is given importance since it is likely to affect the final outcome(Harlfacree, 2011). The material selection is done using the following criteria Thermo power (S) Absolute temp(T) Thermo conductivity(K) Electric resistance (p) ZT BiTe (bismuthtellluride 3.2 300 1.20 W/(m·K) 1.1×105 S·m/m2 83.78 CeFeSb (skutterudite) 5.4 292 2.2 W/(m·K) 1.2×105 S·m/m2 116.11 ZnBe (Zinc-beryllium) 2.7 290 3.7 W/(m·K) 1.15×105 S·m/m2 20.57 SiGe (silicon-germanium) 3.2 305 1.8 W/(m·K) 1.3×105 S·m/m2 48.05 From the above materials we select Zinc-beryllium because has low ZT which good materials for the proposed design. These materials that were used are good for heat dissipation especial when forced convection is necessary (Jason, 2011). There was thermo conductivity of 1.20 W/(m·K) and Electric resistance at 1.15×105 S·m/m2, while its corresponding cold having an efficiency of 105%. Calculated ZT in this case is 20.57. The variation of fin length gave different heat transfer Rate values which calculation of the overall efficiency could be done together with performance of energy balance across the heat recovery system. In this case it is clear that there was absorption of heat energy from the environment. The flow rate for cold water was maintained constant, variation of lengths rate from a lower value to a more significant value gave an increased thermal efficiency. Some extra heat could be recovered, thus variation of these gave different values which determinations of the overall efficiency is possible (Hoyle, 2000). Heat recovery systems where the water would enter the system on one end and then flow parallel to each other for recovery to take place. As these exchanges positions because of cases in weight, heat would be transferred from one lower side where there are higher temperatures to the one with lower temperatures. The eventual temperature at the outlet would be different from that recorded from the initial setting (Harlfacree, 2011). It is from these temperature differences that their mean and differences calculates efficiency of the system at various variations of flow rates. Once the system is on, temperature changes were recorded alongside their flow rates(Harlfacree, 2011). In a heat recovery having a fluid flow, the portion near the boundary surface, is affected since all water are practically not in viscid and hence the solid surface imparts a no-slip condition which in turn retards the smooth water flow giving rise to a slower moving boundary layer. When a flow enters a heat sink, a boundary layer is almost immediately formed circumferentially around the inner side of the turbo Steamer. T The core of the flow which is in viscid in relation to the walls is restricted from freely moving due to the growth of a viscous boundary layer (Crouse and Anglin,1995). The velocity profile is thus constrained to a no-growth condition and fully develops only after traversing downstream. Theoretically the downstream pressure drop recorded would be linear. The transverse velocity profile, mentioned above, also helps in understanding the development of the boundary layer. The flow of a fluid through a closed conduit can either be laminar or turbulent. This difference of flow characteristics is dependent on the flow velocity and viscosity of the fluid and the conduit diameter. The wide fluctuations and waviness of the graph could allude to the turbulence, or a phase of transition to turbulence flow property inside the pipe(Harlfacree, 2011). Design for manufacture, assembly and disassembly / maintenance. Thermal expansion is another source of failure in material selection. The graphitization levels are also utilized to ensure that the alloys properties that are achieved by the end of the day feature all that is to be achieved for the type of operational environment. It is therefore in good order for the semi-crystalline and random orientation of the matrix to be observed clearly while manufacturing the material in order to ensure that a good outcome in physical and mechanical properties is achieved(Shi, Kong, Li, Uher, Yang, Salvador, Wang, Chen and Zhang, 2008). While crack propagation can be eliminated by random orientation of the Zinc-beryllium, other properties like thermal and electrical conductivity can also be approached using the similar selection of materials and then ensuring that a proper analysis is carried out in the laboratories to ensure the same is achieved for usage in engine. Another approach used to determine the properties of this important material is by either utilizing thermosetting or thermoplastic type of fibers. Using the thermosetting approach shall definitely give Zinc-beryllium which is the most important material aspect too. Another property of Zinc-beryllium that is important to look into while choosing materials for the system and especially with regard of the turbo steamer for Toyota land-cruiser V8 is the differential hydrolysis level achievable. Then the degree of heat treatment achievable on a material is important to look into since this affects the threshold temperatures that can be withstood. The correlation between bonding and materials orientation has also been discussed in several aerospace and matrix literatures thereby showing how important this topic is when it comes to technology (Jason, 2011). The designed heat recovery designed will be positioned in the engine as shown below The design for turbo steamer will circuit with wire with the following design Figure 1: circuit for turbo steamer The above wire design of the system that will be used to conserve. However, the supposed system is normally monitored as a way of determining the relative conditions regarding functionality so as to plan well certain preventive and maintenance procedures. The supposed heat recovery of the system does occur over a low temperatures as opposed to the high temperatures (Hanlon, 2005). The resistance for electric energy transfer phenomenon which makes the heat flow rate directly proportional to the temperature difference and indirectly proportional to the resistance to heat flow. The resistance to heat flow is a factor of the attributes of the material as well as the area available for heat transfer. The rate of heat flow at any point (kW/m2 of transfer surface) depends on: Heat transfer coefficient (U), itself a function of the properties of the fluids involved, fluid velocity, materials of construction, geometry and cleanliness of the teat recovery system Temperature difference between hot and cold streams Total heat transferred (Q) depends on: Heat recovery surface area (A) Heat transfer coefficient Average temperature difference between the streams, strictly the log mean (DTLM) The total heat transferred Q = UADTLM The heat transfer rate is expressed as: Transfer Rate = Transfer Coefficient x Transfer Area x Temperature Difference Given a situation where the two fluids and their temperatures are given the problem of heat recovery system becomes one of increasing the area available for heat transfer. However, Incropera and Dewitt (2002) point to another factor that affects heat recovery across a surface with fluid on either side. This depends on the flow characteristics of the fluid on either side of the heat transfer surface. Close to the surface, a thin film forms where the flow is laminar and its thickness depends on the rate of flow, the viscosity of the fluid, the turbulence of the flow materials of construction of the heat recovery system, and the cleanliness of the recovery surfaces. With higher turbulence, the thickness of the film decreases and reduces the resistance offered to the heat flow. In a given heat recovery system, operating under fixed conditions, it is not necessary to undertake calculations that require incorporation of the different factors that affect overall heat recovery and heat recovery rate mentioned above. By monitoring the flow rates and the inlet and outlet temperatures of both hot and cold streams it is possible to calculate the overall heat trecovery coefficient using only the specific heat capacity of the two fluids. The heat loss rate from the hot stream is Qhot = Vhot x Cphot x (Tinlet – Toutlet) Similarly, the heat gain rate of the cold stream is Qcold = Vcold x Cpcold x (Toutlet – Tinlet) Where, Q is the heat recovery rate, V the mass flow rate of the relevant stream, Cp the specific heat of the fluids and T the temperature. It is important to note that the density and specific heat of fluids change with temperature and it is important to adjust the mass flow rate and the specific heat to the actual temperatures. One may take additional readings of the temperature at the mid-point of a concentric tube heat exchanger but this is very difficult to achieve in other configurations and it is normal to take an average of the inlet and outlet temperatures for adjustment of the flow rate and the specific heat of the fluids. Because heat recovery system operates in an open environment and particularly in the case of turbo steamer will insulated, it is expected that some heat from the system will either be lost to the environment, or gained from it affecting the overall efficiency of the heat recovery system. The efficiency of the heat exchanger is thus a ratio of the heat gained by the cold stream to the heat lost by the hot stream(Shi, Kong, Li, Uher, Yang, Salvador, Wang, Chen and Zhang, 2008). The overall heat transfer coefficient of the equipment can also be calculated from the equation For this we need to calculate the heat exchange area and the log mean temperature difference (LMTD), which is calculated as using the formula Where, ΔTa is the temperature difference between the two streams at the inlet of the hot stream end and  ΔTb is the temperature difference at the exit end. Design risk assessment and management Risk management occurs in stages namely identification, assessment, response and review. Risk identification involves a timely knowledge of the predisposing factors and triggers of risks. This is a continuous process. Risk assessment is the in-depth analysis of the extent to which the risk can affect the project. Response is the action the company takes to mitigate and/or control the effects of a known risk whereas review is the quantifiable results of a mitigation measure. Different projects face different risks depending on the type of job, location, materials for use, labor and size of the job among other things (Walker, 2007). Risk is managed so as to achieve project objectives in terms of cost, quality, safety, time and environmental sustainability. Of most importance is the cost since it is difficult to find a project whose initial cost equals the final cost. The risks affecting design costs include economic factors and legal problems, inflation, designer capabilities and technical problems. Buried manmade objects and/or unidentified hazardous waste also pose a risk to the design team. Underestimation of design time and the length of time taken to approve the design are a cost too(Walker, 2007). Economic and financial risks include abrupt change of government policies on the minimum wage in the course of the road construction period, delay or failure to process financial releases for the project. Of concern is inflation which increases production costs since the unit cost of inputs consequently increases. Loss of money value in forex exchange affects the costs of the imported inputs(Walker, 2007). Technical risks include incapacity to fully fund the project leading to premature stalling and improperly finished projects. It also encompasses the lack of or inadequate qualified staffing which could otherwise offer the best technical expertise. Risk assessment is one area that within risk management which is more involved with the identification and rating of risks that can be incurred during the whole project. This step is important in order to reduce any chances of complete failure of the project due to unforeseen circumstances which would otherwise have been avoided in the first place. Risks may manifest themselves through the lack of proper planning of the whole project and requires much emphasis in the course of the project. Risks can result in projects total failure, late implementation, poor quality service delivery and suspension of project activities. It is therefore imperative that project risks are managed through a pre-planned alleviation plans. For the effective alleviation of risks, the project has classified risks into three classes; highly expected, most expected and Unexpected. Highly expected risks are those whose probability of happening is more than 50% hence the project steering committee has to put in place, alleviation measures. For the most expected risks, their chances of occurrence are less than 50% but their effects might be substantial hence requiring proper alleviation plan. For the unexpected risks, no alleviation measures are put in place. Design of heat recovery with turbo steamer is susceptible to numerous risks and the table below indicates these risks and their vulnerabilities. It also indicates the counter active measures that can be undertaken in order to mitigate the risks (Hillier, 2004). The sources of information on material acquisition are bids and quotations, purchase orders, requisitions, shipping documents, receiving documents, invoices and subcontracts. Materials are therefore acquired through best price shopping or by performance characteristics as specified by the designer. Project materials are classified into fabricated units and stand off the shelf materials(Walker, 2007). The materials used for designed project should be environmentally friendly emitting minimum carbon into the air. Rapid advances in technology have presented technological risks to designers. Designs and structures that have been used in the past are becoming obsolete in dealing with new ventures which present greater complexity and/or scale. Obsolesce is a risk especially in materials and design. Engine conditions create a high level of uncertainty for designed system whose functions are not clearly marked. Sometimes the design is changed or modified after engine has been made has begun where installation procedures were not anticipated (Harlfacree, 2011). References Crouse, W. H. & Anglin , D. L.,1995. Automotive Engines. Singapore: McGraw-Hill Endo, T., 2007. Study on Maximizing Energy in Automotive Engines. New SI Engine and Component Design and Engine Lubrication and Bearing Systems. SP-2093 (01) Hanlon, M., 2005. BMW unveils the turbosteamer concept, Harlfacree, G., 2011. BMW unveils new 'turbosteamer' part. Production-sized component cuts fuel consumption by 10 per cent< http://www.expertreviews.co.uk/cars/24324/bmw-unveils-new-turbosteamer-part> Heisler, H., 1999. Vehicle and Engine Technology, 2nd Edition, Oxford: Elsevier Ltd. Hillier, V.A.W., 2004. Fundamentals of Motor Vehicle Technology. 5th ed. United Kingdom: Nelson Thornes Limited. P50-65. Hoyle, D., 2000. Automotive Quality Systems Handbook. Oxford: Butterworth Heinmann. p19-35. Jason, 2011. BMW Turbosteamer and Thermoelectric Generator Projects Aim to Harness Heat Energy. BIMMERPOST NEWS< http://f30.bimmerpost.com/forums/showthread.php?t=579012> Shi, X, Kong, H., Li, P., Uher, C., Yang, J., Salvador, J. R., Wang, H., Chen, L., & . Zhang, W., 2008. Low thermal conductivity and high thermoelectric figure of merit in n-type Bax YbyCo4Sb12 double-filled skutterudites Walker, S. (2007). Sustainable Design. 2nd ed. USA: EarthScan. p15-23. Read More