Portable Air Conditioner

The portable air conditioner heats or cools a room without you having to lay pipes or cables. You set it down, insert a battery (slot 0) and a liquid canister (slot 1) and choose the mode on its switch: Cold (0) or Hot (1).

The canister is its heat store. This is how the game code calculates:

• Cold: each tick the device pumps up to 2,500 J of heat from the room air into the canister contents. If the canister is warmer than the room, the output drops; at a 100 K difference only 1 % remains. Without a canister, or if it holds neither liquid nor at least 6.3 kPa of gas, it does not cool. Each tick this costs 25 J from the battery.
• Hot: with a canister it pumps the other way, up to 2,500 J per tick from the canister into the room. Without a canister or with frozen contents, a heating element supplies 250 J per tick.

A calculation: a room of four cells at normal pressure needs about 27,500 J per kelvin. At full output that is 11 ticks, a good 5 seconds per kelvin. When cooling, though, the heat ends up in the canister – at some point it is so warm that little happens any more. Then you swap it for a cold one.

Limits from the code: cooling does not work when the room is colder than −10 °C, heating not above 50 °C. The room needs at least 6.3 kPa. If the pressure in the canister rises above 40 atm (about 4,053 kPa), the device vents gas into its inner tank of 250 litres; if that is above 40 atm as well, it stops. With Open (lever) you empty the inner tank into the room.

For comparison, the fixed devices:

It is ideal for the first days and small rooms; a fixed system needs no canister swaps. More in Heating and cooling: wall heater, wall cooler, air conditioner, radiators.