Inexplicable thermally inspired human behaviour - aka Hot And Cold

Inexplicable thermally inspired human behaviour 

I first noticed this phenomenon as a data centre infrastructure project manager way back in the 80's - the innate and inexplicable inability of clients (read: people) to discern environmental thermal variations. 

Let me explain.

A data centre is a big, self-contained, self-regulating box in which all the computer servers that run a business or indeed the world we know, are housed and protected. Here these myriad processing or networking devices sit in stacks in row upon row of cabinets so inevitably they are producing heat as they go about their business. You've felt the heat from the fan at the base of your laptop or your desktop computer - well imagine hundreds, sometimes thousands of those all huddled in one room cumulatively discharging their hot air into the surrounding space 365 days of the year nonstop. It gets hot in there pretty quickly.

So there's an obvious need for temperature control in the data centre or the devices, robust as they most certainly are, would eventually overheat and malfunction with potentially disastrous consequences - erm...a banking network might go offline, your local ATM might shut down, your search engine application might crash and so on...

But that isn't the point.

Machines, like humans, operate at optimal efficiency under ideal conditions and the temperature at which they'd set the thermostats in the early data centres was around 19 or 20ºC which is the desired average return-air temperature at which the air conditioning units operate - in other words, much colder air (say around 14 or 15ºC) would be supplied (usually underfloor or via ducting) by numerous cooling units to the inlets of the servers and the heated air discharging from the back of them would return to the cooling units to be cooled down again in a perpetual cycle. There was a permanent heat source (the servers) and a permanent cooling source and both ran 24/7.

Now for humans, (and of course it varies) the optimal temperature at which we feel most comfortable - Goldilocks syndrome - not too hot, not too cold  just right - is around 23 or 24ºC.

So just imagine, if you will, a data centre that is operating continuously at an average temperature of 19ºC. In summer in South Africa where the daily average temperature is around 28 - 30ºC, walking into a 19ºC environment is going to feel very cool. After a while, if you're just sitting or standing in there, it begins to feel cold.

Conversely, when in winter the average outdoor temperature may be as low as 6 or 7ºC, 19ºC actually feels "warm". But it isn't - it's still just 19ºC. It's us who are simply being subjected to lower ambient temperatures thus the sudden influence of another 11º of "warmth" has an immediate and significant effect on us.

But the pinnacle of terrestrial evolution seemed incapable of working that out, even when the handily placed thermostats in the data centre read 19ºC. The facilities operator, having just walked in from a bracing winter morning of 7ºC feels HOT. Ergo: the room is hot, ergo: the systems are about to crash, ergo: he must log a call with the data centre support contractors responsible for the cooling system because clearly it's broken..

I cannot recall how many times I received nuisance calls under such circumstances where I would slowly yet patiently go through the routine of asking the obvious questions:

Are there any alarms on the HVAC units? 

No...

What is the temperature reading on the thermostat displays? 

19ºC...

Are there any alarms on the servers themselves? 

No...

Do you know what the present ambient temperature in Joburg is? 

Um - not sure - maybe around 8 degrees...

And the computer room is 11 degrees above that right?

Yeah....?

Well, that's all you're feeling - the difference between 8 and 19 degrees of temperature.

Right?

So there's no problem.

But it's HOT in the computer room....

(Patiently) No, it isn't. It's nineteen degrees in there - it just feels HOT because it's very COLD outside...

Huh? No, it's HOT in there....

Well if you wish us to despatch a technician to verify that the data centre temp is nineteen degrees, it's going to cost you money unnecessarily. 

But it's HOT in the data centre...

And so it would go on.

Then there are the office workers who exist in another reality altogether. They suddenly discard all rationality as winter arrives when they have to brave 7ºC between the house and the car or the walk to the station then again between station and office. No longer is 23 or 24ºC the optimal temperature for them - now this has been promoted to 30ºC or higher and everything in the office building has to be set up that way. Alternatively local heaters are set up close by and they slowly roast themselves over several hours like chickens in a broiler.

It's beyond any rational comprehension. HVAC systems have to work overtime and the heating bills skyrocket.

It's the same in the car - the heater is set to maximum because that's why there is a maximum right?

I would visit office buildings in South Africa on winter mornings where instant sweating would be induced in these hot, oppressive spaces but where women (mostly) would be wandering around in this 30º environment still huddled in jackets and scarves, wooly pants, boots and so on. It used to blow my mind - still does.

And then you head into the city on that winter evening and the very same women are parading around in skimpy outfits for the sake of the latest fashion trend with nary a goosebump to be seen while you, dressed like Nanuk of the North, are freezing your ass off.

Go figure.