Executive Summary This memo focuses on enhancing the thermal efficiency of a crockpot. The current thermal efficiency of the crockpot was found to be 25.8%. This low efficiency is due to heat loss to the environment, inefficient energy transfer design, and losses from assumptions made during testing. Based on our results, we are confident that insulating the exterior and implementing higher quality materials can greatly enhance the crockpot's performance.
Background A crockpot is a kitchen appliance known for its convenience in preparing meals. The crockpot tested has a ceramic outer shell and a removable inner container. Heat is transferred into the cooking vessel by utilizing an internal heating element secured to the wall of the outer shell.…show more content… By using water, we were able to use its well known properties and could easily be measured. For this experiment, 2 liters of water were placed in the pot and was allowed to acclimate to room temperature inside the crock pot for an hour before testing to allow any heat transfer from the water to crock pot to be minimized.To measure the energy coming into the crockpot a tool called a “Kill a Watt” was used. With the Kill a Watt we were able to measure the power draw in kW at any given moment as well as the KwH to verify our results were accurate. The way we measured the temperature was with a thermometer balanced in the middle of the water to create an average temperature reading, not affected by being too close to the heating component of the crock pot. Before plugging in the crockpot, an initial temperature was captured for the water and ambient temperature. After plugging in the crock pot, we were able to keep it at a constant power level. Additionally, every 30 seconds a measure of water temperature, wattage and watt hours was recorded. Using these values as well as the fluid properties of water, we were able to calculate all of our values shown in this memo. For example, the COP was measured using an energy balance that utilized the initial and final temp of water and atmospheric conditions such as pressure.This helped us to find the internal energy change of the water. Dividing the change in internal energy by the total energy gave us 25.8% efficiency. Additionally, by using the same parameters and data, the amount of entropy generated was calculated. Using the same energy balance as before, the total loss of energy from heat escaping to the surrounding temperature can be found by setting the change in internal energy equal to the work in from the power outlet minus the heat energy out. Since we know the value of the energy going in
