Current TRL: 4 (11/19/2021)

“All components for the cooling system (temperature and flow sensor, radiator, pump, fan, tubing, reservoir) are present. To achieve TRL 5, the cooling system must be fully incorporated in the dyno room with the motor and motor controller.”

Cooling System

 

 

      Current State of the Entire Cooling System

 

           Radiator View from the Back Side of the Car

Currently, the entire cooling system is located near the back of the car right behind the driver’s seat and below CarMan. The sensors and water pump are attached to an aluminum platform which is then mounted onto the interior frame of the chassis on one of the vertical support bars. Attached in series with 0.5” flexible tubing is the radiator which is mounted on one of the horizontal support bars behind the driver seat. This radiator then has a mounted fan that directs air into the radiator’s fins to cool the higher temperature water with ambient air temperature.

Literature Review

The cooling system is an essential part of the motor and motor controller, which ensures that they can perform under ideal operating temperatures. As the name implies, the cooling system keeps the motor and motor controller at reasonable temperatures to prevent overheating from occurring. The car cooling system is very important to the car. If the motor is operating at temperatures above its recommended standard, then the efficiency will drop accordingly and produce less work to drive the entire system. A good cooling system will increase the service life of the motor, ensure better motor performance of the car, and improve personal safety. Based on the importance of the cooling system, we first need enough knowledge to help us make a cooling system. This literature review will help to understand the working principle and function of each part of the cooling system and a better idea of how to design one. We need to systematically optimize the old cooling system to ensure that it can function properly when added to the car with other subsystems.

Full Literature Review

Design Proposal

This system’s design problem involves accurately modeling the cooling system with theoretical calculations regarding the amount of heat transfer it can provide for the system. Another challenge would be that the cooling system may not be able to produce enough heat transfer enough to reduce the temperature of the motor and motor controller, to an acceptable level. The motor and motor controller must be kept between a range of temperatures for the maximum efficiency of the motor.

A test bench for the cooling system would provide a systematic test for each component of the cooling system. Components of the cooling system will be situated in an organized fashion and can be tested in series with the motor and motor controller when moving the test bench to the dyno room for testing.

Goal

Currently, the cooling system team wants to fully test and document the capabilities of the current cooling system and implement it with the entire car. Furthermore, for the future senior design team, the current cooling system team also hope to develop a simple testing rig for the cooling system to systematically test each component as well as all the components within this system in unison.

Diagrams

Wiring Diagram (2020-2021) PDF

Fitting Diagram (2020-2021) PDF

Manuals

User Manual (2020-2021) PDF

Maintenance Manual (2020-2021) PDF

Testing Plan (2021-2022)

Manual Testing Plan (2021-2022) Google Doc

Published Code and Standard

The Codes and Standards provided by The American Society of Mechanical Engineers website only insight to the thermal capabilities of the cooling systems related to wet-cooling towers. The method used in the cooling system would be considered a dry cooling, as there is no water directly exposed to the air for cooling in the current system.

PTC 23-2003(R2014)

Metrics and Constrains (2021-2022)

Metrics:

  • The cooling system must cool the motor and motor controller down to a sufficient temperature (Below 50 degrees Celsius)
  • Cooling system is able to provide at most 7.5 kW of heat transferred out of the motor
  • The time required to cool to a desired temperature
  • The length of tubing provided for the cooling system should be limited as best as possible to improve flow rate
  • Components in the cooling must be easily replaceable.

Constraint:

  • The whole cooling system must fit behind the car and have enough space to coexist with the motor and motor controller as well as other subsystems.
  • The stability of the entire cooling system during car movement.
  • The test bench need to ensure availability, mobility, and can effectively replace different subsystems for cooling systems.
  • Temperature of the water through the tubing must be less than 70 C.

Broader Impact

For race cars, speed is always the most important goal. But in order to ensure the safety of the driver for our electric vehicle, the motor and motor controller will not overheat, so the cooling system will be necessary. The main job of the cooling system is to dissipate heat into the air or heat sink to prevent any components from overheating, but the cooling system also has other important functions. For instance, the engine in a car works best at a moderately high temperature. If the engine becomes cold, it will accelerate the wear of components, thereby reducing the efficiency of the engine and emit more pollutants. Therefore, another important function of the cooling system is to keep components at a constant temperature to ensure that they’re running efficiently. We hope to achieve cooling system with a lighter weight and still ensure sufficient cooling efficiency despite the size. Companies with specific interests in dry cooling methods involving radiators and dry cooling methods would be able to analyze our data and possible utilize our testing methods to produce similar or desirable results in terms of the amount of heat transfer.

 

Theoretical Calculations (11/22/2021)

Current State of Test Bench (2021-2022)

The purpose for this test bench for the cooling system is to allow individuals to systematically tests each component on the cooling system in housing

Flow Rate Sensor

  • YF-S201 flow sensor:
    • Connected in series with the temperature sensor
    • Measures flow rate in terms of a volume over time
    • The yellow wire from the sensor outputs Hz which can be converted into liters per hour based on the manufacturer datasheet
    • The linear relationship between frequency and flow rate
  • Flow Rate Sensor’s Datasheet (This datasheet gives the basic information of the flow sensor that we used. It will help the theoretical calculations for flow rate.)

Flow Rate Sensor Validation Testing

Flow Sensor MATLAB code

Temperature Sensor

  • Koolance TPL010K temperature sensor:
    • This sensor is connected in series with the tubing through the cooling system in order to measure the temperature of the water. This will ensure whether or not the cooling system is transferring enough heat out of the motor and motor controller to have it perform in tolerable conditions.
    • There’s a thermistor  in this sensor where the resistance changes based on surrounding temperature
    • Resistance and temperature correlation can be found from the datasheet
  • Temperature Sensor’s Datasheet (This datasheet gives the basic information of the temperature sensor that we used. It will help the theoretical calculations for heat transfer rate.)
  • Temperature Sensor Testing Brief Report

Radiator 

 

Pump

  • Koolance PMP-500 pump
    • The cooled water will be cycled back with the pump in order to continuously cool the motor and motor controller, keeping it within operating temperatures
    • The pump will receive 12 V at full power. The red and black wires represent positive and negative 12 VDC and the yellow wire represents the control voltage
  • Pump Drawing from 2018

 

Fan

 

Reservoir

 

Current Tubing Sizes 

  • These are the current tubing sizes that have the quick disconnect connectors on both ends
  • Length

Other components

Cooling System Mounting Panel

  • A five-sided panel attached with the following components:
    • Koolance PMP-500 pump
    • Koolance TPL010K temperature sensor
    • YF-S201 flow sensor
  • Panel Dimensions
    • Link to Drawing File (PDF)

DC-to-DC Converter

  • This is a step down voltage converter from 24 volts to 12 volts located inside of Carman.
  • The pump and the fan require a smaller voltage to run, which is why there is a DC-DC converter to provide 12 volts to these two components.

Formal Budget of year

Subsystem TRL Chart

TRL What does this look like? Expected Completion Date
9 The cooling system is fully implemented and performing at the competition Competition Date
8 The cooling system is fully implemented and ready for competition 04/01/21
7 The cooling system is fully implemented and tested at Metzgar 03/01/21
6 The cooling system is tested with other subsystems inside the chassis  12/15/21
5 The cooling system is tested with the motor/motor controller in the dyno room 11/23/21
4 Flow and temperature sensors are tested with specified values in a controlled environment and proven to be accurate Completed
3 Concepts of the entire cooling system are understood and  Completed
2 Cooling system assembly completed  Completed
1 Components of the cooling system are chosen Completed

 

Meet the Team

Justin Wu:

In charge of testing the temperature sensor, designing the test bench, and determining the theoretical calculation for heat transfer for the entire cooling system

Kaizhao Liu:

In charge of testing the flow sensor tester, designing the test bench, determining the most efficient tubing connection with the motor and motor controller

Additional  Documentation

Cooling System Bill of Materials 2020-2021

Cooling System Test Datasheet 2021

Cooling System Test Report 2021

General Overview 2020-2021

Cooling System Poster 2020-2021

Initial Tech Readiness Level (9/28/2021)

Previous Cooling System’s Information