Six Cabins, Six Air Conditioners: Diversity Factor

A camp plant that trips is undersized and one that burns fuel is oversized, and the argument usually comes down to a single number: diversity. Add up every nameplate in every cabin and you have the connected load; what actually runs together is the peak demand. Design peak equals connected load times the diversity factor.
 The difficulty is what factor to use. The 60–70 percent common in housing is often too low on a camp. Campsite data makes the point: the old practice took 0.65 for twenty pitches and 0.4 above fifty, on the reasoning that not everyone boils water at once. But modern motorhomes carry roof air conditioning, induction hobs and 200–800 Ah lithium banks, with pitch supplies rising from 6–8 A to 16–25 A. Add hot days when everyone cools at the same time, and gas-free cooking that puts every induction hob on together, and the old factors fail. Current guidance is 1.0 up to about twenty pitches, and no lower than 0.8 beyond that.
 Camps have one more concentrator: shift change. At seven in the morning and seven in the evening everyone showers, cools, boils and charges at once, and that half hour runs far above the daily average. So peak sizing cannot look at installed equipment alone; it has to ask when things coincide. Take six cabins at 1.5 kW of cooling, 2 kW of water heating and 0.5 kW of everything else: 24 kW connected. A 0.6 factor gives 14.4 kW, the plant gets ordered to that figure, the real shift-change peak reaches 24 kW, and the result is an overload. The missing 10 kW is one outage.