Engineers trial new tech to stop energy going down the drain

Engineers from Trinity College Dublin are leading a five-year project that is aiming to stop useful energy going down the drain. They are piloting a system that aims to recover energy from waste water at Penrhyn Castle -- a National Trust property in Wales. Additional testing sites in Ireland and the UK are set to follow in the coming months.

Using the new technology, the engineers will extract heat from the waste water flowing out of the vast Penrhyn Castle kitchens at between 40°C and 50 °C, and use this to warm the cold water coming into the kitchens.

Associate Professor in Engineering at Trinity, and the Dŵr Uisce project lead, Dr Aonghus McNabola, said: “We have, alongside our partners at Bangor University, been working closely with the National Trust on this project over the last 18 months. We are hopeful that we will further develop this exciting new heat recovery technology and that it may be used more widely in the not-too-distant future.”

“This technology has the potential to considerably reduce energy consumption at Penrhyn Castle, and wherever else it is integrated. We are excited by the possibilities, and are very grateful for the opportunity to design and implement it with the support of The National Trust.”

If successful at Penrhyn Castle, the technology will be rolled out at other sites across Ireland and the UK, where it should support the growing energy recovery sector and could potentially save millions of euro over the coming years for organisations that produce large quantities of waste heat.

Senior Environmental Advisor at the National Trust, Keith Jones, said: “Energy efficiency is about more than just reduction in use. It’s also about the re-use of waste, or what we currently consider to be waste.”

“The National Trust and I suppose most other users of energy, from households to hospitals, spend a lot of money on making water hot for many reasons, from hot showers to dish washing. But what do we then do with this warmed resource? We flush it down the drain and then start the process all over again, warming water from very cold to hot again. This is very wasteful in terms of energy and this project at Penrhyn Castle is seeking to close this circle of wasted energy.”

The technique that will be trialled at Penrhyn consists of using the hot drain water, with peaks up to 50°C, to preheat the mains water before it enters the current heating (biomass) system at the castle. Thanks to this preheating, it will require less energy to heat the hot water, saving energy and money, while also reducing greenhouse gas emissions.

This project is being supported by several different companies who have provided expertise in developing this project, including Detectronic, whose technology has been used for wastewater flow monitoring, and Showersave, whose technology will be adapted for heat recovery at the Castle.

The Dŵr Uisce project is part of an Ireland-Wales Cooperation Programme 2014-2020 project supported by the European Regional Development Fund (ERDF).