Heated Snow Shovel Handle

Transcription

1 Heated Snow Shovel Handle Progress Report 1 Prepared by: Rielle Jensen David Quinn Molly Flynn Kejd Marika Jake Milford Kaden Mior Prepared for: Dr. Emeka Oguejiofor, Ph.D, P.Eng. Mr. Paul Doiron, P.Eng. St. Francis Xavier University Department of Engineering ENGR 232 Engineering Design & Communications II March 10, 2017

2 2 Table of Contents Overview of Project Goals... 3 Project Accomplishments... 3 Project Difficulties... 4 Next Steps... 4 Resources... 7

3 3 Overview of Project Goals The goal of the project is to address the problem of cold hands due to holding a snow shovel in frigid conditions, for a long period of time. However, as shoveling snow is inevitable in climates like Canada s, a solution to the problem is to add a heating element to the handle of the shovel to warm the user s hands. The design needs to have a material that will keep the shovel sturdy and waterproof, include a heating element that will keep the users hands warm without overheating, as well as power that heats the element without causing any issues. Project Accomplishments There have been calculations done to have an estimate on the necessary voltage to heat the coil. The formulas relating to the power dissipated from the heating coil to the power needed to heat the grip to the desired temperature are used in order to determine the material properties of the grip, and the material used in heating the coil. Power dissipated by a resistor (heating coil): P = V 2 /R (EQ 1) where P=Power Dissipated, V=Required Voltage, and R=Resistance of Material Heat needed to increase a material by a certain temperature (by conduction): Q/t = k*a*(δt)/d (EQ 2) Assuming this heating coil is completely efficient in transferring power to heat (Q/t = P): P = k*a*(δt)/d (EQ 3) where P= Power Needed, k= Thermal Conductivity, ΔT=Temperature Change, A= Inner Area of Grip, and d=thickness of Grip Combining these formulas (P = P): V 2 /R = k*a*(δt)/d (EQ 4)

4 4 It has been decided that Butyl Rubber will be used for the grip because it has a low thermal conductivity, and Nichrome was chosen as the heating coil material because of its high resistivity. Solving the equation, it has been found that the necessary voltage is around 6.65 volts. This value is an estimation of the total voltage needed to operate within our specified temperature range. Because of this, a 9-volt set up was chosen and can be limited according to necessity These calculations lead to the decision that battery power would be best for heating the shovel, however an issue arose with respect to the fact that regular alkaline batteries tend to freeze when subjected to colder temperatures. Lithium batteries are the best solution, as they work in temperatures as low as -40 C, and come in AA, AAA and 9V form. They are more expensive then alkaline, but it is worth it for the purpose of the shovel. A design has been chosen for where the heating elements are located on the shovel, as well as the handle screwing on to the top so the batteries can be placed inside. Drawings are attached showing our design choices. (Figure 2., Figure 3.) Project Difficulties For building a prototype, Dr. Frank Comeau was consulted and was asked for the use of the circuits lab. He informed the group that the circuits lab does not have any heating coils to use for testing. A heating coil needs to be purchased in order for the prototype and testing to happen, which has set back the start of making our prototype. Our website has also been held back slightly due to not being able to start building the prototype, which is reflected in the updated Gantt Chart. Next Steps The next steps are constructing the prototype, and designing the mechanism to prevent overheating. The heating coil will be purchased at a local hardware store, which will be used for testing along with the battery power and the device that stops overheating. The device will incorporate either a potentiometer or thermistor to control the amount of

5 5 resistance of the wire, but will ultimately have a fuse that will break if the wire gets too hot. That decision will be made shortly, and testing will move forward. The schedule for the rest of the project is outlined in the Gantt Chart. (Figure 1.) Figure 1. Gantt Chart showing the progress of our group. Figure 2: Inventor Pro drawing of the prototype.

6 Figure 3: Inventor Pro Drawing of the prototype handle, with screwing mechanism. 6

7 7 Resources Coil Heaters. Retrieved February 05, 2017, from Custom Aluminum Parts Machining. Retrieved February 07, 2017, from Machining/page486.html Energizer Ultimate Lithium Batteries. Retrieved February, 28, 2017, from Farrington, R. J., & J, F. R. Patent US Heated handle construction. Retrieved February 06, 2017, from InvestmentMine. Retrieved February 09, 2017, from Glassman, J. Patent US Heated snow shovel. Retrieved February 02, 2017, from Nichrome. Retrieved February 02, 2017, from Rubber Daily Price. Retrieved February 02, 2017, from The HEFT. Retrieved February 03, 2017, from EQ 1: Ohm s Law, Retrieved Jan 30, 2017 from EQ 2: Formula for heat transfer by conduction, retrieved Jan 30, 2017, from Properties of Nichrome, retrieved Feb 2 from Properties of Butyl Rubber, retrieved Feb 2, 2017 from