Omar Abdelaziz, Kai Wang, Edward A. Vineyard
Oak Ridge National Laboratory, United States
Keywords: Thermal energy utilization, absorption, Lithium Bromide, Water Heating, energy efficiency
In 2008, the residential water heating consumed more than 14% of the residential primary energy use and is expected to become the second largest residential primary energy user by 2030. This poster presents recent efforts towards the development of an absorption water heater (AWH) technology for retrofit applications with no infrastructure modifications. The heart of this AWH is an air source heat pump driven by natural gas. This technology is a breakthrough in natural-gas-fired water heating because it provides an EF exceeding 1.0 for the first time using fossil fuels. The design will be used as a drop-in replacement for conventional gas storage water heating equipment: no natural gas supply line upgrade and no ventilation modification are needed. The absorption heat pump augments the primary energy with energy extracted from the surrounding ambient temperature, resulting in a higher EF than previously attained for natural-gas-fired water heating applications. The AWH technology uses an advanced absorption heat pump cycle and aqueous lithium bromide (LiBr) additives to prevent LiBr crystallization at low ambient conditions. This cycle configuration results in lower absorber temperature operation and thus lower risk of solution crystallization. The system performance has already been simulated using ABSIM insuring technical feasibility.