Not long ago, I found myself in the interesting position where my client wanted a standby generator and an uninterrupted power system (UPS), and he wanted me to buy it and have it installed for him. I asked him if he meant that he wanted me to get a contractor to do this and he said no, I want to give you the money and you get a contractor to do the work. He was sick of dealing with contractors.

So, in the fullness of time, I bought a standby generator and had it installed and connected and it worked just fine. When I went to see the UPS people, it was a different story. They were quite prepared to sell me a UPS but wanted to know how I was going to air-condition the battery plant room. So I said I am not going to do that. Oh, they said – do you know that the life of the battery that we supply deteriorates significantly if the battery is not kept at 25 °C. So I said no, I would keep the battery room-ventilated. Oh, they said, how will that keep the batteries at 25 °C or below? So I said, well, if the outside air temperature is about 30 °C, then the inside temperature will be about 25 °C if the room is relatively well ventilated and there you go. Oh, they said, what if the outside temperature gets above 30 °C? Well, I said, in Cape Town about once month a year.

The argument went back and forth until I finally told them, rather tensely, that I was damned if I was going to specify a UPS which relied on keeping an uninterrupted power supply to an air-conditioning unit to keep the batteries cool so that the UPS worked. It was a complete waste of UPS, I said. I told them that I had specified many UPS systems and all of them had Plante lead acid batteries. These batteries did not have to be kept cool – they had no falling-off capacity with age and they had a life expectancy of 20 years or longer. Oh, said the UPS people, but they are not maintenance free. I said yes, but that is not a difficult thing; for example, air-conditioning systems have to have the filters changed, and motor cars have to have the tyres pumped up and the water topped up. Why is an occasional visit to check how a battery is doing such a bad thing? The costs of inspecting the battery cannot be anything like the cost of running an air conditioner to keep the battery cool 24 hours a day.

Unfortunately, the UPS person went straight to my client and gave him the awful news that I was going to install batteries which required someone to visit them every two weeks. Lips quivering, the client instructed that the air- conditioning system went in. The reason why UPS people push the maintenance- free batteries (also known as VRLA batteries) is that they make a great deal of profit out of them. If you get a client stupid enough to put in an air-conditioning system to keep the battery that runs the air-conditioning system cool, then the one downside of the VRLA battery, the tendency to heat up and blow up, is overcome – and vast profits await.

It is not only batteries that apparently require large air-conditioning systems; suppliers of computer systems routinely request abnormal levels of cooling for a computer or a set of computer racks. Without the air-conditioning systems supplying these racks, they will apparently fail. Consequently, large computer systems require large air-conditioning systems that have to be backed up by large standby generators. I believe that large computer systems do require air conditioning and ventilation, but I very much question the order of magnitude of the air conditioning installed commonly in industry. Even worse, very often, the power consumption of the computer server racks is overestimated by 50%. At the end of the day, the suppliers of all this kit convince the client that this is what is needed and walk away rich. Poor engineers . . . but rich.