Absorption chillers : their feasibility in district heating networks and comparison to alternative technologies

In recent years, a rising cold demand can be observed, which is e.g. due to increased requirements on climate control. The majority of this cold is currently provided by compression chillers. At the same time, district heating companies exhibit a lack of sales during summertime, which could e.g. be diminished by the operation of thermal driven cooling systems. This work assesses absorption chiller technology in combination with boundary conditions implied by district heating systems. A theoretical comparison with compression chillers is provided and thereby interesting technology is identified. An analysis of the respective absorption chiller market in Germany is performed and a real case cold generation system is evaluated. Furthermore, the economic competitiveness to compression chillers is considered and environmental footprints are compared. The LiBr-water single-effect absorption chiller is identified as the only reasonable machine, to be driven by district heat. Factors of highest influence are load factors, prices for heat, efficiency and size of the chillers. Possible application fields can be found e.g. in large office buildings, including server rooms. Absorption chillers are less appropriate for the use as stand alone systems and fluctuating load profiles, but conceivable as complementary to compression chillers, providing a constant base load. Buffer storages are essential for high load factors, continuous operating conditions and consequently efficiency. The calculated acceptable price for heat is significantly lower than typical market prices for district heat. Nevertheless, the provision of the product "cold" under agreed-upon conditions is conceivable as business model for district heating companies.