Compare the amount of heat pumped by the Peltier element in the experiment with the total energy consumed in the experiment. Answer the questions.
We have already estimated the amount of heat that needs to be "removed" from the water
| The amount of energy released when cooling water to the solidification temperature () | |
| Freezing water releases (TeX parse error: Extra open brace or missing close brace) | |
| Total amount to be removed () |
Test power and test time
| Average power used in the test () | |
| Test time () |
Energy used in the test
| Energy used in test () |
Igasuguse masina, kaasa arvatud soojusmasina tööle panemiseks on vaja energiat. Meie katses ei olnud otseselt energiat „puudu," meil oli vaid vaja teatud hulk energiat veest eemaldada. Soojus aga ei liigu külmemalt kehalt soojemale iseenesest, seda tuleb pumbata. Pumpamiseks kulub energiat ja pumpamisega kaasneb pumba soojenemine.
Võime saadud numbreid kasutades hinnata ka meie seadme kasutegurit, kui jagame pumbatud energiahulga energiaga, mille me pumbates kulutasime.
How is this knowledge useful to us?
As we have seen, it took a lot more energy to make a tiny juice ice cream than we calculated in theory. This is often the case in other areas of life, as energy transfer is generally not 100% efficient. A good example is the fossil-fuel car, in which a maximum of 40% of the fuel consumed is converted into energy to move the car, and in most cases the figure is even lower. Electric cars are a bit different, with a minimum efficiency of 70%.
In any energy-consuming activity, we should bear in mind that a large part of the energy is not actually used for that activity, but for something else, such as heat. Therefore, it is always worthwhile to consider a large margin for these activities.