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Keeping Tractors Cool

Keeping Tractors Cool Keeping Tractors Cool Keeping Tractors CoolOne critical engineering difference between farm tractors and over-the-road semi tractors is their speed. Eighteen-wheelers zip along open roads at 65 mph or better. A farm tractors usual plowing speed is about 4 mph, so keeping farm tractors cool is a major task.This big speed differential has big heat-transfer implications. Very little air flows naturally under the hood. Farm tractor designers have always had cooling problems. Those are compounded by farm tractors comparatively small engine compartments. Large, turbocharged diesel farm tractors have up to five under-hood cooling systems one each for the engine, the fuel, the transmission oil, the air compressor, and the cabin air conditioning. New emissions regulations from the U.S. Environmental Protection Agency (EPA) have created additional cooling challenges.Farm tractors rely almost entirely on one big fan to drive off all that welcheste heat. Making sure it work s efficiently has always been a tedious task. The under-hood components often were juggled to optimize airflows against the fans appetites for engine power and fuel. That forced manufacturer Case New Holland (CNH), Burr Ridge, IL, to build and test a prototype for each arrangement. There was never enough time or budget to optimize a design.Until very recently, engineers at CNH used hand and spreadsheet calculations. Those were verified, to one degree or another, by physical prototypes. And that was a problem.Automating CalculationsCNH solved the problem by automating heat-transfer calculations with computational fluid dynamics (CFD) software supplied by Fluent, Inc., Lebanon, NH. CNH engineers and managers in Burr Ridge say the Fluent package was chosen because its software accurately simulated extremely complicated cooling packages while keeping computational requirements to reasonable levels. Fluent is a unit of ANSYS, Inc., Canonsburg, PA, a developer of engineering simulation an d analysis software. CNH is a unit of CNH Global N.V. in The Netherlands, and is majority owned by Fiat Industrial S.p.A. in Italy.CNH engineers now model and simulate the flow of air from the fan through the engine compartment and through the heat exchangers used in each of the modules. In the companys new Magnum tractors, the fans power consumption was significantly reduced. CFD made it possible to evaluate enough eignung designs, and several alternatives, to optimize the design. Also reduced were the costs of building and testing prototypes. Fluents software predicted the performance of the proposed designs.Verifying CalculationsThis was the big change. The old calculations had been verified only in a lab and not under the hood, where the fans behave differently. CNHs old methods also were unable to take into account the geometry of the under-hood compartment and didnt show how the air actually flowed, and that uncertainty made the prototypes necessary.CFD inputs included the geo metry of the tractors diesel engines, fans, heat exchangers and other components, and engine compartment sheet metal. The CFD-driven modifications on the Magnums included improved fan designs that draw much less power as well as new oil coolers.Coolant temperatures predicted by the simulation correlated well with measured temperatures. The CFD models had 5 million to 10 million elements and it took 24 to 48hours to run the simulation. These results were considered excellent because they approximated the variability of physical testing. The use of simulation in the design process made it possible to bring the product to market substantially faster than the previous generation of products.Adapted from Efficiency for the Field, by Panos Tamamidis, CFD manager, Case New Holland, for Mechanical Engineering, April 2007.CFD made it possible to evaluate enough potential designs, and several alternatives, to optimize the design.

Benefits of HSA vs. HRA for Health Care Savings

Benefits of HSA vs. HRA for Health Care SavingsBenefits of HSA vs. HRA for Health Care SavingsHealth insurance is designed to help with the cost of medical care, but it doesnt always cover everything. Planning ahead for additional out-of-pocket costs can keep you from experiencing sticker shock when a medical bill arrives. Depending on what type of health insurance you have or what health care benefits your employer offers, you may have access to a Health Savings Account (HSA) or a Health Reimbursement Arsortimentment (HRA). If either of ansicht options are available to you, its important to understand how an HSA vs. HRA compares. Health Savings Account Basics As the name suggests, an HSA is a savings account thats meant to be used specifically for health care. These accounts are associated with high deductible health insurance plans, which may be offered by your employer. You can also opt to enroll in a high deductible plan with an HSA if youre self-employed. An HSA can be used to pay for a broad range of medical expenses, including Doctor visitsPreventative careSpecialty servicesPhysical therapyDrug and alcohol treatment programsWeight-loss programsOrgan transplantsLab testsMedical equipment and suppliesHospital servicesDental servicesVision servicesPrescription drugsOver-the-counter medications The Internal Revenue Service limits how HSA funds can be used to a degree. For instance, you cant use the money in your HSA to pay for things like teeth whitening services, vitamins, hair transplants, exercise equipment or a gym membership. Using your HSA funds is relatively easy. Your insurance company can provide you with a debit card linked to your savings account. You can then swipe your card to pay for eligible medical costs and your HSA provider will furnish a tax statement at the end of the year, showing your total spending and annual contributions. For 2018, you can contribute $3,450 to an HSA if you have single coverage. The limit increases to $6,900 if y ou have family coverage. Employers can make matching contributions to an HSA on your behalf. Total employee and employer contributions cant exceed the annual contribution limit. How a Health Reimbursement Arrangement Works A Health Reimbursement Arrangement differs from an HRA in several key ways. First, its not a savings account per se, nor is it health insurance. You dont make any contributions to the account instead, your employer makes contributions for you. Employers can establish an HRA for any employee under age 65. They also have control over how you can spend down the money in your account. For example, if you medical expenses that insurance doesnt pay for, you could tap your HRA to pay, then cover any remaining difference yourself. Alternately, your employer may set up your plan so that you cover a specific amount thats not covered by insurance then, your HRA pays the rest. In terms of contribution limits, these vary based on the type of HRA the employer has establishe d. An Integrated HRA which is linked to a high deductible group health plan, for instance, has no annual contribution limit. A Qualified Small Employer HRA (QSEHRA), which is designed for businesses with 50 or fewer employees, has a contribution limit of $5,050 for individual coverage and $10,250 for family coverage in 2018. Similar to HSAs, money held in an HRA can only be used for qualified medical expenses. Generally, that includes those expenses covered by your health insurance plan, such as doctor visits, hospital services and prescription drugs. Your employer has the option to expand the scope of coverage to include the full range of expenses that are HSA-eligible, but this isnt mandatory. Benefits of HSAs vs. HRAs An HSA and HRA may seem equally advantageous but HSAs yield some important benefits that HRAs dont. First, the contributions you make are tax-deductible. Deductions reduce your taxable income for the year, which could result in a lower tax bill or a larger refun d. HRA contributions are deductible but only for your employer you get no tax break for having one of these accounts. Next, youre not required to use your HSA funds until you need them. The money you contribute rolls over from year to year and until you withdraw it, it continues to earn interest. With an HRA, your employer decides whether to let you carry contributions over from one year to the next. If thats not an option, your HRA money essentially becomes use-it-or-lose-it. The way you can use funds in an HSA vs. HRA also differs. If your employer doesnt opt to go beyond the expenses covered by your health care plan, you may find yourself paying more out-of-pocket for medical expenses that could be covered by an HSA. Lastly, and perhaps most importantly, an HSA can do double-duty as a retirement planning tool. Ordinarily, withdrawals from an HSA for anything other than health care would be subject to a 20 percent tax penalty and ordinary income tax. If you stay healthy and contin ue to accumulate money in your account during your working years, you can withdraw money from your HSA at age 65 or older for any purpose, without incurring the 20 percent penalty. Youd totenstill owe ordinary income tax on your withdrawal but this can be a useful way to supplement Social Security benefits or retirement income from a 401(k) or individual retirement account. Contributing to an HSA, even if you dont max out your plan each year, could be useful in creating an additional source of savings for retirement. If, however, you only have an HRA available, its important to understand exactly how you can use it to ensure that you make the most of it.