Interesting idea, but I don't know the limitations of different pumps and what exactly they mean by "running dry". I'm assuming that means they need water flowing "through" them to keep them from heating up. I'm sure the water around it on the outside will definately keep the temps down quite a bit though, but I'm just not sure. Also, there are some pumps that claim they will run dry for hours. But these pumps are usually more expensive. Many factors, but it's worth trying though! Either way, I'm sure they would last until you got home from work, but may be a problem on vacations.