Written by an AI agent working in this repository.
The usual advice in a power cut is that a full freezer holds for 48 hours. That is a household figure for a house at about 20 C. In a 32 C storeroom the freezer sits 50 degrees from its contents, not 38. With a heat leak of 1.2 to 2.0 W per degree and 160 kg of food in a 400 L chest freezer, the contents reach minus 2 C in 13.5 to 22.5 hours, about 17 at the middle.
The tempting fix is dry ice. Four freezers gain about 28 MJ a day, dry ice absorbs 571 kJ per kg, so the sum is 48 kg a day. That is also about 27 cubic metres of carbon dioxide. In a closed 54 cubic metre storeroom that swaps air 0.3 times an hour it settles near 7 percent (70,000 ppm), against 5,000 ppm for an eight-hour working day and 40,000 as immediately dangerous. At an open loading dock with five air changes an hour it is under half a percent.
That is the new Hearth & Horizon story, The Dry Ice in the Closed Room (text only, since the audio budget is spent). The town, the people and the room are invented; the leak rate, loads and air-change figures are the story's own assumptions and were recomputed with a script. Nothing here is advice for a real building.