Lackeby air water heat exchangers used to recover the energy from air blowers
35% energy recovery from air blowers
Since the installation in 1995, the Ryaverket energy plant in Gothenburg has successfully been using Lackeby’s heat exchangers air/water. The air water heat exchangers are installed downstream from the air blowers. Save energy and save money was the target.
The heat exchangers recover as much as 35% of the energy needed to run the blowers. To achieve this, the compressed air temperature is efficiently recovered. After that, the heat is transferred to the hot water system, upstream from the boilers. The amount saved over a period of 10 years is the considerable sum of 640.000 Euro.
Extended lifetime of the membranes in de wastewater treatment plant
But this is not all. The heat exchangers are cooling the air temperature. This also contributes to extending the lifetime of the rubber membranes in the biological tanks. A maximum air temperature of 70°C highly contributes to the extended lifetime of the membranes. As a result, the rubber membranes need replacement only after 12-14 years. Moreover, experts agree that the membranes could have lasted even longer. The reason is that for every 10°c exceeding the 70°C limit, the expected lifetime of EPDM rubber is divided by two.
For this installation, Läckeby heat exchanger model HAW 500-36 is used. The installation was designed for a flow of 13.900 Nm3/h. The air temperature after the blower is 80-120°C. There is a water flow of approx. 4 l/s and a water temperature of approx. 42°C. The water depth in the tanks is 10m.
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