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Writer's pictureJeremy Carter

A "Circular Economy" can drive efficiency

Updated: Jun 1, 2019

With so many things in life we as a society it would seem are a sucker for a slogan or two. Perhaps one of the worst in recent times is “Joined up thinking” How stupid do we have to be for our thinking not to be joined up? Do the authors of such phrases draw up a list of the dumbest sayings they can think off and then sell them on to even dumber Counsellors and Politicians?


What I am saying is not that the saying “Joined up thinking” is stupid. Far from it. The saying just reminds that we have not allowed the necessary communication links to allow that level of collaboration. All too often, I think we like to tell ourselves the obvious or something we already know and then take credit for saying it.


“Oh Bravo….. cue long slow clap”


The term “Circular Economy” however, just happens to be the purest genius. It is not such an obvious expression particularly when you consider its current lack of take up. However, when applied in the sustainable sense it becomes an obvious solution to one of our planets biggest problems. The generation of waste.


So how does a circular economy help us reduce our levels of waste? The simplest explanation is that when we no longer require something in its current purpose it is then used for another purpose. It does not take a genius to realise that if something that was waste can be re-purposed, it is no longer waste.


“How can we apply this Circular Economy model to Energy consumption?”


How can we apply the Circular Economy model to Energy consumption? We know Chillers have become incredibly efficient thanks to the massive strides made in refrigeration technology. The waste product generated by the chiller is of course low-grade heat. Which leads to me to wonder why heat recovery systems on chillers are not commonplace.


“Maybe our thinking is not joined up enough?”


Common sense would suggest the majority of organisations that require chillers must also be able to utilise low-grade heat. Could the problem be historic? We have typically sought one system for chilling and another for heating. Failing to realise that connecting the chiller to heating system would help the heating system and save energy. Maybe our thinking is not joined up enough.


In order to capitalise on this “Circular Economy” approach to energy efficiency. I think a good place to start would be seeking out where we waste, discard or exhaust energy.


Those of us who have operated swimming pools will be aware that the air handling systems (AHU) exhaust 30c heat, typically 24hrs a day. Now there are many issues to address here. Firstly, swimming pools exhaust heat due to the required amount of air changes. However, if pools covers are engaged during the night I would recommend that air handling systems can be turned off. I know they can because I have done so. This is something I will discuss in more detail in a future blog, titled “Energy Experimentation”.


A swimming pool AHU will typically employ a run around coil or thermal wheel. This will capture a handful of degrees in temperature from the exhaust air, which it will then transfer to the supply side. This is standard on swimming pool AHU systems and does save energy. However, if the incoming ambient air matches the required set point the exhaust heat will be fully rejected.


I have long thought that even if the run around coil works we are still missing a massive opportunity with the 30c exhaust air.


Possibly a Genius Idea


Some years ago, I had the idea of positioning an Air Source Heat Pump in front of the swimming pool AHU exhaust. Air Source Heat pumps (Heat Pump) are at their most efficient in higher ambient temperatures such as that of an AHU exhaust (30c).



Should Heat pumps be employed in Heat Recovery

The AHU exhaust would supply 30c heated air across the Heat Pump 12 months of the year. Operating in this way allows the heat pump to utilise a source of waste heat to supply a swimming pool with as much running hot water as it can use. Now if you are a regular reader of my blogs you will know this is normally the time to…


“Give it the Big en”


However, when I had this “Genius idea” I contacted several well known suppliers of air source heat pumps. All of which either dithered, didn’t want to install air source heat pumps in this location or just didn’t respond. Talk about being underwhelmed.


“Was this my Dyson moment?”


Writing this now, I regret not pursuing this idea further and have sometimes thought that maybe this was my Dyson moment. Good idea or bad idea the fact remains, heat recovery is a circular economy that clearly isn’t being capitalised on enough. Heat pumps can in my opinion, provide a highly efficient way of capturing this waste heat. We just haven't begun using them in this way


The more I think about the term Circular Economy, the more potential I realise it has for energy efficiency. Firstly, and perhaps most importantly it identifies sources of waste energy, which has to be a significant step towards reducing energy consumption.


Secondly, when applying the “Circular Economy” model to what the sources of waste energy can actually achieve, we are driving innovation. Innovation by its very nature is circular. Perhaps it is not always a perfect circle but I like to think innovation will play a major role in solving our current problems. Such as those of generating waste and wasting energy.


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