Why have Standby Heaters on a diesel engine used in a colocation data centre? Diesel engines used in trucks or boats start OK in cold weather, so why not in a Central London colocation data centre? The answer is that a colo has some special requirements that a truck or a boat does not.
Standby Heaters on a diesel engine used in a colocation data centre - why?
A colocation data centre will most likely have its standby power generated by diesel-powered generators on site. The engines are not special to data centres, but are designed for other applications and then adapted to colocation provider needs. At the little end, up to about 500KW output, standard lorry (truck for Americans) engines are used. At the big end (up to about 1500KW output) the engines are designed for other things, like small ships or big yachts or pipeline pumps. Bigger than that, it’s gas engines or aircraft engines (fancy 25MW of output in a tiny light-weight package?), but that’s going over the top for most colocation providers, or for any data centre. In all of those applications, the engines don’t get molly-coddled. No-one excuses a truck engine that won’t start if it’s a bit cold, or a yacht that can’t move off its berth because it’s chilly, or an aircraft that can’t take off because it’s in Alaska. They’re expected to start first time, every time and work. So why in colo, or in any data centre, do we have to keep them warm?
The answer is that an engine in a data centre or a colo experiences shock loading. A lorry engine is expected to start, warm up then run slowly for a bit before going on the motorway, a yacht engine gets time to warm up before the pilot asks it for real power. In a colo or any type of data centre, the mains failure is detected, the switchgear operates the moment the genset engine has started and attained its set speed, and the load is there immediately. A 1000KVA genset in a colo will have an 800KW max output at the shaft (1,000 is a better number than 800 if you’re a salesman). It’s quite possible for the UPS load to hit the genset within 5 to10 seconds of the start signal being sent, and that’s the whole UPS load plus the battery charging load because the batteries started to discharge as soon as the mains feeds to the colo started to fail. That might be 0 to 500KW in 5 seconds. A bit like asking a Formula 1 car not just to be flat out after 5 sec off the grid, but 5 sec after pressing the start key on a cold engine on a cold day.
Without heaters, the engine might start up OK but stall when the load hits it. And no colo provider or any self-respecting data centre would dare take that risk. So a colocation data centre with diesel backup needs standby heaters to ensure its diesel engines are nice and warm and at the right temperature to go, day and night.
