Articles | Volume 9, issue 1
Research article
27 Jan 2016
Research article |  | 27 Jan 2016

Shower heat exchanger: reuse of energy from heated drinking water for CO2 reduction

Z. Deng, S. Mol, and J. P. van der Hoek

Abstract. The heating of drinking water in households contributes significantly to the emission of greenhouse gases. As a water utility aiming to operate at a climate neutral level by 2020, Waternet needs to reduce its CO2 emission by 53 kton yr−1. To contribute to this ambition, a pilot project was carried out in Uilenstede, Amstelveen, the Netherlands, to recover the shower heat energy with a shower heat exchanger from Dutch Solar Systems. An experimental setup was built in the Waternet laboratory to evaluate the claimed efficiencies. The energy recovery efficiency observed in the lab was 61–64 % under winter conditions and 57–62 % under summer conditions, while the energy recovery efficiency observed in Uilenstede was 57 % in December 2014. Based on the observations, 4 % of the total energy consumption of households in Amsterdam (electricity and gas) can be recovered with a shower heat exchanger installed in all households in Amsterdam, which also means a 54 kton year−1 CO2 emission reduction can be achieved.

Short summary
During a shower, a shower heat exchanger from Dutch Solar System can recover more than half of the thermal energy from the heated drinking water. Under a positive condition, installing shower heat exchangers might lead to a reduction of 54 kton CO2 per year in Amsterdam. The research proves the efficiency and potential of the shower heat exchanger, by carrying out experiments in the laboratory and collecting data from the Uilenstede project site, a student housing estate near Amsterdam.