One of the most efficient ways of transferring heat from one liquid to another, without any contact between the two, is by using a ‘Shell and Tube’ heat exchanger. This type of heat exchanger consists of a shell (a large tube) with a series of small tubes inside it. Hot water flows through the tubes and cold water through the shell, transferring up to 90% of the energy from one to the other in minutes.
If it was that simple, of course most laundries would have installed such a system decades ago. However, laundry water consists of a cocktail of chemicals, dirt, lint and fibre that causes traditional heat exchangers to block very quickly, or need sophisticated filtration, or constant maintenance.
Up to 1200 metres (3/4 mile) of this tube carries the waste water through the exchanger, while the fresh water flows around the outside of every tube in perfect counter flow.
At the heart of Aquatherm is a unique stainless steel tube, formed internally and externally into a double helix.
The waste water inside the tubes is kept in a state of high turbulence, which stops lint and dirt from sticking and increases heat transfer by 75% compared with plain tube. This combination ensures the extraordinary transfer of heat that is achieved in all Aquatherm systems, regardless of capacity.
Aquatherm’s unique design uses a combination of methods to achieve a very high rate of heat recovery throughout its long working life, without the need for cleaning or maintenance. In order to keep the system compact, the exchanger is constructed in 4 sections, linked with continuous tubular headers, with specially formed stainless steel tubes carrying the waste water, creating a controlled velocity and high degree of turbulence . The system can deal with waste water from any number and type of washing machines.