Drain Water Heat Recovery in Domestic and Commercial Settings

Much of the energy consumed in heating water for domestic appliances and sanitation is wasted to the drainage system. This waste not only exists in the domestic sector, but also applies to many commercial buildings such as hotels, schools, hospitals or leisure centres. The energy efficiency of such processes can be improved through the adoption of drain water heat recovery (DWHR) systems, as hot waste water passes through a heat exchanger and the heat energy is transferred to incoming cold water streams or to a hot water storage system.


Determining the potential impact of DWHR technology

A desk study quantifies the potential for energy recovery using DWHR systems in domestic and commercial settings. This will enable a market assessment for DWHR systems, highlighting the potential for new business activity and growth using this technology.


Lab-scale development of DWHR units

A prototype DWHR system was developed to recover the heat in waste water from commercial kitchen drain water. The system looks to integrate a direct DWHR system with the grease trap. Because grease traps are mandatory in commercial kitchens, the prototype aims to provide financial and space savings through this integration.


Field demonstration of DWHR in the hospitality sector

Field-scale demonstration sites of the developed technology will be deployed in both Ireland and Wales to demonstrate the potential for energy recovery in commercial settings. The task comprises the design, installation and monitoring of the system. Energy savings and CO2 emissions reduction will be monitored. The site will be used for site visits and case study work in the smart specialisation cluster.