Different from traditional compression electric refrigeration units, LiBr Absorption Chillers operate mainly through thermal energy conversion with low electric power consumption. The equipment performance is highly dependent on on-site working conditions, and its selection logic is fundamentally different from the “capacity-on-demand” principle of conventional electric chillers. The core selection principle is to determine the maximum operating capacity of the unit based on actual on-site boundary parameters and then match the cooling demand of the project. The overall selection is carried out based on four core parameters: driving heat source, chilled water conditions, cooling water conditions, and cooling capacity requirement. These parameters restrict and verify one another, serving as essential prerequisites for reliable unit adaptation, stable operation and optimal energy efficiency.

1. Driving Heat Source Parameters

As the core power source of LiBr Absorption Chillers, the driving heat source is the primary decisive parameter that determines the unit type, energy efficiency grade and theoretical maximum cooling capacity. It ranks first in the unit selection criteria, and all relevant parameters shall be confirmed according to stable measured on-site working conditions.

Key heat source parameters include heat source type, operating temperature, operating pressure and available heat supply capacity, with different heat sources corresponding to dedicated unit models. For steam-driven projects, the pressure of saturated steam shall be clarified to distinguish single-effect and double-effect units and select equipment with matching energy efficiency. For waste heat hot water projects, the supply and return water temperature as well as stable water flow shall be verified to select suitable hot water-type units according to heat source grade. For projects without available waste heat, direct-fired units can be adopted. The type of fuel such as natural gas or fuel oil, together with rated gas and oil supply pressure, shall be specified to ensure stable heat supply of the combustion system and sustainable power output for the refrigeration cycle.

2. Chilled Water Working Condition Parameters

Chilled water parameters are core customized indicators on the user side, which directly determine the actual cooling output of the unit, distinguish standard units from customized units, and significantly affect the accuracy of cooling capacity calculation and terminal cooling performance.

Three key indicators shall be confirmed during selection: chilled water supply and return temperature, rated operating flow and system working pressure. The standard working condition for conventional central air conditioning is 12℃ inlet and 7℃ outlet, under which the unit can achieve its rated nameplate cooling capacity. Special water temperature requirements are common in industrial process refrigeration and non-standard scenarios. Non-standard heat exchange conditions will change the heat transfer efficiency and cause cooling capacity attenuation; therefore, the actual effective cooling capacity shall be recalculated according to on-site water temperature conditions. In addition, the system working pressure shall be verified to match the pressure bearing grade of units, pipelines and terminal equipment. Reasonable water flow shall be configured to ensure uniform heat exchange and stable cooling effect, and define the complete operating boundary of the user side.

3. Cooling Water Working Condition Parameters

The cooling water system serves as the core heat dissipation structure of the chiller. Its operating parameters directly limit the full-load operation limit and act as critical constraint conditions for long-term stable operation, which are easily overlooked in conventional selection. Even if the heat source and chilled water conditions meet the design requirements, mismatched cooling water parameters may still lead to insufficient cooling capacity, high-pressure alarms and frequent start-stop failures.

It is necessary to verify the cooling water supply and return temperature and design flow, and conduct comprehensive verification in combination with local summer extreme wet-bulb temperature, cooling tower specification and machine room ventilation conditions. The industry standard cooling water condition is 32℃ inlet and 38℃ outlet, which matches conventional heat dissipation equipment. For projects with enclosed machine rooms, undersized cooling towers or high summer ambient temperature, the heat dissipation efficiency will decrease significantly. In such cases, working parameters shall be corrected in advance, unit load shall be reasonably verified to avoid over-limit operation, and stable operation under extreme high-temperature conditions shall be guaranteed.

4. Cooling Capacity Requirement

Cooling load is the final verification parameter for unit selection and constitutes the core difference between LiBr Absorption Chillers and electric chillers in selection logic. Unlike electric chillers that select equipment according to cooling demand preferentially, LiBr chiller selection requires deducing the maximum stable cooling capacity based on the three boundary parameters of heat source, chilled water and cooling water, before matching and verifying with the actual project cooling load.

During selection, the peak cooling load, normal operating load and long-term operating duration shall be accurately calculated based on building structure, equipment heat dissipation and process constant-temperature requirements. A reasonable margin shall be reserved to cope with extreme weather, equipment aging and future load growth. The final unit model and parallel quantity are determined according to the verified effective cooling capacity, so as to balance operational stability and long-term energy-saving performance.