I have kept hatching eggs that I am collecting for incubation in an extra refrigerator used for drinks at the warmest setting it could be set. Ideally temperature should be between 45 and 60° Fahrenheit. Approximately 7 to 15°C. I’ve also used a small cooler with ice packs. Keep a thermometer wherever you decide to store them to make sure the temperature stays in the correct range. Anything lower than 45°(7) may kill the embryos. Higher temperatures and you risk that the eggs start to develop before you put them in the incubator.
I have also successfully hatched eggs that have been in the regular refrigerator at colder temperatures for several weeks, though the chance of these eggs hatching is lower. Where ever you decide to store your hatching eggs, they should be set out at room temperature for approximately 6 to 12 hours before setting them in the incubator. Good luck.