When we think about the water we flush down the toilet, drain down the sink, or pour out when we bath or shower, we tend to focus on how much of it is going to waste. Since water is a finite resource, our primary approach is to use less water, so that we waste less of it. We are driven to take shorter showers, close the tap when we brush our teeth, and recycle any wastewater we can. There’s another angle though, and we’re moving in that direction.
The latest innovation involves heat. Warming your water – whether it’s for a shower, dishes, or tea – is one of the highest forms of energy expenditure in a home. When that home is your actual castle (as opposed to a metaphorical one), the utility bill gets quite high. Still, you need the warm water to bear life inside those cold castle walls, and once you’re done using it, the water gets flushed away, still retaining all its warmth.
Think about it. That hot shower water touches your skin for a few seconds before it goes down the sewer. What if there was a way to harness that heat and use it to warm the rest of the water you need for your shower?
Gothic castles in Wales
That’s exactly the thinking behind a new project at Penrhyn Castle, run by Bangor University and Trinity College Dublin using a £50,000 grant from the EU. The research project has run for about 18 months. Key names in the project include Dr. Prysor Williams, a senior lecturer at Bangor U, and Phil Tuxford of Detectronic, who supplied the scientific study equipment.
This Welsh Castle – located in Gwynedd – receives visitors every year numbering in multiple tens of thousands. It uses 1.3 million litres of water annually, much of it heated and is run by the National Trust. In terms of upkeep, its maintenance costs are the third-highest in the UK, so cutting down the heating bill could save the exchequer millions. It’s a 19th-century castle built in gothic neo-Norman style, so keeping it open is crucial as a cultural monument.
When (hot) water is leaving the castle, it passes through a wastewater pipe that runs through the kitchen, past the cellar, and into the septic tank. The pipe is fed by dishwashers, sinks, and sterilisers all over the castle. The idea is to harvest heat from this water, then redirect that energy and use it to heat water elsewhere in the castle.
Testing … testing … 1 … 2 … 3 …
Some of the ideas floated were to let water into the castle using the same pipe that leads water out so that it gets heated in the process. Other options were to heat the inlet pipe itself, so that water warms on the way in rather than using a dedicated heating tank. This is the principle applied to insta-showers, and it saves a lot of power.
The verification phase is almost done, so this harvest-and-reheat plan is expected to be implemented in a few weeks’ time. If it succeeds, it can be applied in schools, hotels, homes, and hospitals all over the UK. In addition to re-using the harvested heat, researchers are thinking about adding a heating pump to the system.
The pump could use a heat exchanger to harvest and recover 40% of heat lost from the flushed water. Penrhyn Castle has a railway museum, a café, and more than 100 rooms, which means it has quite the carbon footprint. To minimise its effect on the environment, it dropped its oil heater for a biomass heater and generates 25% of its energy through solar panels. This heat harvesting project will bring its expenditure even further down.
To learn about Interfil’s contributions to pioneering technology in liquid waste management, and to see what patented equipment we have available, call Interfil today on 02 9533 4433.
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