Pew Sheet – 24th October 2021

The Web Master writes ‘WANTED: Someone to join Roger and Simon to operate the service streaming

console. Training will be provided in the Sundays leading up to Advent and Roger and Simon have developed a comprehensive set of guidance notes.

Operation is simple and should be within the abilities of anyone using a PC or laptop on a daily basis. This is an opportunity to participate in a very meaningful digital ministry. The more volunteers we get, the more we can divide up and minimise the work!

Interested? Email simonwoodworth@gmail.com. ‘

If you turn to the backpage of this Pewsheet, you’ll read more from Simon Woodworth, our Web Master , as it was also his turn this week for Random notes. Fascinating stuff!

Random Notes CCCXCIX

This is intended as a follow-on to a previous Random Notes concerning grid battery technology. This note continues the theme of Ireland’s national energy supply problems but comes at it out of left field!

We are all aware of the Data Centre controversy. Anytime you hear someone talking about something being “in the cloud,” in reality that thing is sitting somewhere in a big shed in the countryside. Those sheds are full of computers, and they consume a lot of electricity and water. Both are needed to power the computers and to cool them down. Ireland is a popular location for data centres because of its temperate climate. Also, just about any IT / tech / software company you can think of has its European headquarters here. What is not generally known is that 30% of all EU data is hosted in these big sheds right here in Ireland. This has huge implications for electricity demand and for waste heat generation. But why do computers generate so much heat? A good few of us will be familiar with a laptop getting hot on our laps. Desktop PCs have fans and heatsinks to keep their central processing units (CPUs) cool. Where does that heat come from? There are two main reasons for this:

First, every electrical appliance generates heat. Some, like electric kettles and ovens, do it deliberately. This is achieved through electrical resistance, which concerts an electrical current to heat. This is very desirable for your cup of tea or Sunday roast! But all electrical devices exhibit some electrical resistance and so generate some heat. And if that’s not their primary purpose, it represents a waste of energy and a loss of efficiency. But electrical circuits must contain some resistance by design, so waste heat is inevitable. The best circuits can achieve over 90% efficiency, so waste heat is minimised, but never zero.

Second, computers contain an enormous quantity of very small electrical circuits inside them. It is no longer unusual to find in excess of five billion transistors in a CPU alone. Those transistors, which all exhibit some resistance by design, all generate heat in a very small area. The concentration of heat can raise temperatures to that comparable to a rocket exhaust if a heatsink and fan are not used. The heat that is removed from the CPU must be passed to the air outside the computer. That air must in turn must be cooled by air conditioning, otherwise it can reach temperatures in excess of 50 degrees Celsius. (I’ve seen it happen!). Redesigning computers to run cooler requires a fundamental rethink at the level of quantum physics, which is no easy task. Quantum computers actually run extremely cold, but they are not yet suitable for widespread use and their refrigeration circuits also generate heat! The alternative is perhaps to use less computers but that would require a total rebuilding of the world economy. This seems unlikely right now, given our reluctance to engage with the realities of climate change.

So, what can we do? It is a physical reality that almost any process we can think of generates heat and computers are no exception. Could we put that heat to good use? The good news is yes. IBM has a data centre heading a public swimming pool in Switzerland, for example. There are many other cases of waste heat reuse. The technology is not cheap, but the benefits are measurable. The waste heat can be sold to local business and houses. Based on US figures, a data centre consuming 1MWh of electricity per annum could save nearly 5,000 tonnes of CO2 per year using waste heat recycling. With 30 data centres in the planning pipeline in Ireland, the government needs to introduce planning requirements to maximise such waste heat recycling.

SJFW