DE-5 Heat Exchanger

The DE-5 consists of five trays that each contain four spirals. The cold domestic water flows through the coils, and the hot wastewater flows on top of the coils in the opposite direction of the domestic water, causing it to heat up. Wastewater flows from the top down through the trays to the bottom tray and then further down the drain. The domestic water enters the bottom tray and runs up through the trays to the top tray, after which it is fed into the building. As the hot wastewater migrates down through the trays, it gets colder, because the energy is (taken out and) used for the cold domestic water, which gets warmer for each tray it enters.
The DE-5 is suitable for heating domestic water in systems using most kinds of heaters, including oil, gas, district heating, geothermal, solar, etc.

Render of the DE-5

DE-5 Specifications
Dimensions: 1.10 m diameter and 1.60 m height
Flow Capacity: 30-70 L/min
Pipe Dimensions: According to need
Pressure Tested: To 1 MPa (10 bar)


The heat exchanger is made of material with a long service life. The expected lifetime is 30 years or more. Materials are environmentally compatible. It is expected that 99% of materials can be recycled when the heat exchanger must be replaced. The case is made of plastic, which thanks to new technology can easily be recycled. The trays are made from stainless steel (316L), whose durability is better than normal stainless steel and is 100% recyclable. The remaining bits can also be recycled without major problems.
The DE-5 is produced on the Faroe Islands, in Sweden, and in Denmark by staff with a high level of expertise. The majority of the used tools are especially made for the production.


The DE-5 is a passive and simple system. This is an advantage in installation. The below figure illustrates how the system can be connected to drain pipes from showers. The number of units that are connected depends on the fluid flow of a given drain system. The optimal efficiency for a single unit can be reached with a flow of 30-70 L/min.

Swimming Poo Installation Illustration
DE-5 Installation Example
Warm water from the showers passes through the heat exchanger, which feeds the reclaimed heat into the boiler. Several units can be connected in parallel for cases where a greater flow occurs.