Student: Chancellor Linarez

Mentor: John Choi

Abstract

A water jet cutting machine can cause excess heat and humidity within a closed building, while also making it more difficult for the user to pick material off the cutting table. Water temperatures can reach as high as 150 degrees Fahrenheit in the tank. A system that would reduce the temperature of the water in a water jet tank would be beneficial for the occupants in the room in providing a better more comfortable work environment. Data was collected while the machine was in use. The data includes; temperature of water leaving the nozzle, the rate of change of tank water temperature over time. This data was used in determining design requirements for a heat exchanger system to keep water below 100 degrees Fahrenheit. A water to air heat exchanger with a rating of 20 kW was determined to be suitable for the application, assuming operation in a 88 degree Fahrenheit ambient air operating conditions. To manufacture the water to air heat exchanger, a series of copper pipes will run through aluminum fins, and a fan mounted to the unit. Glycol will be circulated through the unit and run through a copper coil submersed in the water jet tank. A circulating pump will be used to circulate glycol through the system. With the heat exchanger in place the temperature of the water increased at rate of 0.05 degrees Fahrenheit per minute during a 12 hour period. Without the heat exchanger in place the water temperature increased at a rate of 0.08 degrees Fahrenheit per minute. With the heat exchanger in place, the water increased in temperature 38% slower than without the heat exchanger.

Presentation

5 thoughts on “Heat Exchanger”

  1. Chance,
    This seems like a good way to be able to control the water temperature considering how high they can get inside the tank. I saw that the water temperature increased 38% slower with the heat exchanger than without it. Do you know what the rate would be with an ideal heat exchanger or does it depend on multiple things?

    1. Chancellor Linarez

      Assuming the ideal heat exchanger was used in the same test, the rate the water temperature increased would be 60.1% slower rather than 38%. But it would probably work out different because the ideal heat exchanger would have a higher rate of heat transfer (24kW instead of 18.7kW), therefore; cooling off the water faster and it would hit the point that the temperature of the water stabilizes at an earlier time. So, the average change in water temperature per minute would decrease and be lower than 60%.

  2. Nice work Chance,
    The quality of work, and attention to detail on this project is great. Can you sweat solder the aluminum cooling fins to the copper piping for better conductivity around each interface?

    Kelson

    1. Chancellor Linarez

      You can sweat aluminum to copper. However the fins are not pure aluminum there are an alloy and I’m not quite sure which alloy but it is very soft. So soldering is difficult when dealing with three different materials; copper, aluminum alloy, and the tin/silver solder. It all starts to become a mess. Brazing would work better but the aluminum fins are thin as well as the pipe wall thickness so the heat required in brazing may just end up melting the fins or pipe. There are some epoxys that will join aluminum to copper and help the conductivity.

Leave a Reply

Your email address will not be published. Required fields are marked *