Experimental investigation on an ammonia–water–lithium bromide absorption refrigeration system without solution pump

Experimental researches were carried out on a novel ammonia–water–lithium bromide ternary solution absorption refrigeration and air-conditioning system without solution pump and distillation equipments. The experiments were conducted by using three kinds of NH3–H2O binary solution and 17 kinds of ternary solution with difference in mass fraction of NH3 and LiBr. The experimental results showed that the vapor pressure of the generator in the system would be lower than that of the generator in an ammonia–water absorption system. In above two situations the same ammonia mass fraction and the same solution temperature were kept. The amplitude of vapor pressure decrease of the system generator would be larger with the increase of the mass fraction of LiBr. The maximum amplitude of decrease would be of 50%. With the increase of the mass fraction of LiBr, the coefficient of performance (COP) of the system would be increased initially, and then decreased later when the mass fraction of LiBr exceeded a certain value. This value was about 23% for the solution with ammonia mass fraction of 50% and 55%, and about 30% for the solution with ammonia mass fraction of 60%. Compared with the ammonia–water system, the COP of the ternary solution system with the same mass fraction of ammonia would increase up to 30%. With the ammonia mass fraction of 60% and LiBr mass fraction of 30% applied, the COP of the ternary solution system was increased up to 0.401. It was 51.89% higher than that when binary ammonia–water solution with ammonia mass fraction of 50% was applied. In above two operating situations, the temperature of hot water, cooling water and chilled water in the system would be kept almost constant, respectively.

► An absorption refrigeration system with ternary solution of NH3–H2O–LiBr was set up.
► Performance of the NH3–H2O–LiBr system without solution pump was firstly tested.
► Generator pressure in NH3–H2O–LiBr system was lower than the one in NH3–H2O system.
► The COP of the NH3–H2O–LiBr system was 51.89% larger than the NH3–H2O binary system.
► The optimum mass fraction of LiBr of about 23% led to the largest COP of 0.401.