Get Wiser

The Leaf – Issue 17 – What is Heat Recycling and How Could Data Centres Save Your Local Swimming Pool?

For many, 2023 ended in a flurry of snow in a lastminute cold snap. Now we hope that you’re emerging from your January hibernation and looking forward to the year ahead, and what a great time to commit to a more sustainable year in 2024!

When we counted up the beans and compared our energy use during winter 2023 to that of 2022, overall, our various Drayton energy-saving projects saved 16% energy, that’s a massive 294,000 kWh which equates to 88,788 kg CO2e (carbon dioxide equivalent) saved that won’t be contributing to climate change.


How Did We Save This Much Energy?

At Drayton, the brand behind Wiser, we don’t just recycle our waste glass, wood, cardboard, metals, paper, plastics, oils, food, paints, solvents, batteries and electrical components at our Zero to Landfill site, we're also recycling and repurposing energy.

One of our projects was the installation of a heat exchanger now fitted to our air compressor, with the purpose of recycling the heat created by the compressor’s normal functioning that would normally be lost into the air.

Now, that heat gets recycled into our water system to heat water in our onsite bathrooms. Cool, right?! Or rather, hot. And we’re far from the only ones doing this.

Heat Recycling at Drayton - Factory Air Compressor Powers our Hot Water

Find out more about how we’re reducing our gas and electricity use at our Plymouth factory and offices and won a Schneider Electric award for our energy saving programs.


How Data Processing Centres Could Save Public Pools From Closure Using Heat Recycling

The Guardian recently reported on hopes that up to 150 public UK swimming pools could be heated by recycled heat from computer data processing centres thanks to a tech start-up called Deep Green and £200m of backing by Octopus Energy.


According to research by the Guardian England has lost almost 400 of it swimming pools since 2010, so cost-saving schemes like this could help safeguard these valuable facilities now and for the future.

A concept trial to heat a local pool using recycled heat from data centres ran right here in Devon last year at Exmouth leisure centre which, like many of its kind, is struggling with increasing energy costs.

The scheme would also benefit data centres, since the UK’s running out of space to accommodate the servers needed to fuel our growing digital demand, so by splitting some out and building mini data centres close to public pools this would help meet demand and cool the water faster so that it can recirculated back into the data centres for cooling servers.

It’s a brilliantly simple idea:

  • Water used to cool servers in the processing centres collects a large amount of heat.
  • The heated water is fed to public pools.
  • The water loses heat and is passed back to the processing centre to cool servers again.
  • The cycle continues, saving energy for the public pools, reducing bills and helping to keep more facilities open.


“The partnership has really helped us reduce the costs of what has been astronomical over the last 12 months.” - Sean Day, Manager, Exmouth leisure centre

Read the full Guardian story here

These success stories prove that innovative thinking around energy recycling is possible on both small and larger scales, so let’s look at what’s possible for you at home that you can start right away.


How to Recycle Heat Energy at Home – Our 7 Tips


1. Make full use of airing cupboards

If you have a hot water tank, it’s good practice to insulate it well to reduce wasted heat. But even well-wrapped tanks can give out heat, so put them to good use airing out lightly damp fabrics. Try installing slatted shelves to maximise air flow.


2. Utilise those hot spots!

Many homes have warm spots often in the floor where heating pipes lie underneath, place washing airers over them to dry clothes faster and reduce your use of tumble dryer. That’s if you can get there before the cat or the dog does!


3. Leave the oven door open after use

When the oven has been turned off and where safe to do so, make use of the excess heat to keep the kitchen warm and the heat will rise to any floors above too. Just be mindful of the safety of children and pets.


4. Open the curtains when (or if) the sun appears

Keeping curtains shut on cold days can help retain heat after the heating has been on, but when the sun is shining (however rare!) throw open the curtains and let the direct sunlight warm the room.


5. Get sociable!

The human body emits around 100 Watts of heat even at rest. During exercise it’s as much as 1,000 Watts, that’s enough to boil a litre of water in six minutes! People together raise the temperature of the room, so gather friends and family for a film or games night, or even a workout or dance-off to recycle that heat and save energy!


6. Reclaim heat from your appliances using a heat exchanger

Otherwise known as a heat recovery ventilation system, heat exchangers can be retrofitted to appliances including wood-burning stoves, fridges and washing machines.


7. Install a heat pump

A more costly but long-term option to heat your home would be a heat pump, which harvests heat from air or ground sources, and you may be eligible for a grant to install one. Several smart heating controls including Wiser are heat pump compatible.

Read more about our sustainability journey at Wiser About Sustainability