ISSN Online: 2377-424X
International Heat Transfer Conference 12
Miniaturized Shell-and-Tube Heat and Mass Exchangers for Absorption Heat Pumps
摘要
A shell-and-tube heat exchanger with small diameter tubes was experimentally investigated as an absorber for a
residential ammonia-water heat pump. This configuration has a high surface/volume ratio, and low thermal
resistances compared to conventional geometries. It was demonstrated that an extremely compact absorber (76.2
mm outside diameter, 0.508 m long) with 253 tubes of 2.54 mm inside diameter with the solution flowing
vertically downward through the tubes can transfer the absorption duty of a 10.55 kW cooling load absorption
heat pump. Experiments over a wide range of solution and coolant flow rates and vapor fractions were used to
deduce overall and tube-side absorption heat transfer coefficients. High performance was achieved without any
surface enhancement, and with very low solution and coolant pressure drops. This geometry offers considerable
versatility to address a wide range of heat load and pressure drop requirements, and can be used for almost all
absorption heat pump components (absorbers, desorbers, condensers, and evaporators).