University Developing New Solar Thermal Device

The thinking is that the new device, which will be low cost, could be incorporated into new social housing as well as retrofitted into a range of other properties.

Existing solar thermal technologies can provide 60 percent of a household’s hot water at a cost of around £4,000, but Dr Mervyn Smyth and Dominic McLarnon of Ulster University have been testing low-cost alternatives designed for the UK solar water heating market for over 10 years.  They estimate that Solacatcher will cost around £500 and will provide between 15 and 20 percent of domestic hot water.

Solacatcher consists of a black cylinder positioned vertically and formed from three concentric tubes. The outer tube forms the aperture and casing while the inner tubes make up the collector and the storage element. The tubes form an annular space which is subject to lower pressure.

“At a very low pressure, at around 0.05 bar, it will boil off at 35°C to create vapour inside the cavity that condenses on the outer surface of the inner vessel, giving you a latent heat transfer” said Dr Smyth.

“The existing distributed systems work fine — I have it in my own house — but you’ve got piping arrangements, control systems and pumps, which all add in additional cost, whether that be components or bringing specialist labour in, and you’ve got major disruption to your existing systems as well.”

The team is currently testing a prototype device in the field and in the university’s solar testing facility. The prototype measures 1.2m in height and has a volume of 40 litres. The team hope to start introducing it to local authorities shortly but they also think that it could be used for temporary structures such as transit accommodation in military barracks, shelters that form part of disaster relief programmes and even beach huts and caravans.

“Anywhere where you’ve got a cold feed going into a hot water storage tank, as long as you’ve got access to that cold feed” Dominic McLarnon said.