RENEWABLE ENERGY - HEAT RECOVERY FROM WASTE WATER


General conditions


The following factors are decisive for a successful implementation of projects in the area of heat recovery from sewers:
- Short distance between large consumer (administration, swimming pools, industrial operation, multiple family dwellings) and the location of heat recovery.
- Waste water temperature as constant as possible of approx. 10-15 ° C or higher.
- A waste water quantity of minimum 10 l / s.
- Sewer of minimum DN 1000 for subsequent installation. For prefabricated sewer elements > DN 400.
- A low heating flow temperature and the heat recovery system laid out as a bivalent plant.
- Sufficient hydraulic capacity in the channel segment with minor constriction.
- Waste water quantity and its fluctuations, contamination in the sewer segment as well as waste water temperature are of central significance and must be clarified beforehand.
- Waste water flow should be as high as possible (target value > 1.0 m/s), so that the shear forces keep the bio film / deposits at a low level.
- Contamination of the heat exchanger to be determined by output recording (volume flow of circuit, flow and return temperature of circuit, sewage temperature).
- The goal should be:
- No cleaning of the heat exchanger required (except in case of canal
  cleaning).
- No or minor maintenance work required during the system's useful life.
- An economically viable overdimensioning of the heat exchanger (surface)
  to ensure that a performance reserve exists..
- Practical examples show that cooling of the waste water is usually marginal and hardly of relevance for the operation of the waste water treatment plant.
- Guide valur for a heat extraction capacity of 2.5 kW / m2 at a waste water temperature of 12 ° C, waste water f of 200 l / s, AT 6 ° C, flow speed> 1m / s and without other special measures.
- Data from practice are to hand.
- Solutions are ready and available for (almost) any requirement.
- Technology is proven and implemented: "HEATING" or "HEATING AND COOLING".The latter is highly economical, but special attention must be paid to technical aspects and environmental laws.
- Ideal also in combination with canal renovation or new construction.