# New Developments and Progress in Absorption Chillers for Solar Cooling Applications
## 3 Newly Developed Commercial Absorption Chillers
### Single-Effect Double-Lift (Half-Effect) Absorption Chiller
In addition to individual solar thermal cooling applications, the large temperature glide in the driving hot water and the low return temperature are especially suitable for the operating conditions in the DH networks and for delivering cold with this chiller during summer. Another type of single-effect double-lift water/LiBr chiller driven by hot water was developed and commercialized by the company World Energy Co., Ltd. (Gunpo-si, Gyeonggi-do, South Korea) [36]. The company's first-generation (2 AB product series) of this type of absorption chiller was developed with the Korea District Heating Corporation in 2005 and was further improved in 2009. Their second-generation highly efficient chiller (2 ABH product series) was developed by 2013 and certified in 2018. The advantages of the 2 ABH product series are high efficiency at full and partial load operations (10% thermal COP improvement at full load, i.e., from 0.64 to 0.71); lower operatingcosts and footprint (14% and 20%, respectively); and a smaller cooling water pump and cooling tower (8%). The absorption cycle schematic and external view of this chiller technology are illustrated in Figures 7 and 8, respectively. Figure 6: Single-effect double-lift water/LiBr absorption chiller machine, type DXS, developed by Hitachi Johnson Controls Air Conditioning Co., Ltd. Adapted from References [16; 35]. (**a**) absorption cycle schematic; (**b**) absorption chiller external view. Note: AABS = auxiliary absorber; ABS = absorber; ADES = auxiliary absorber; ASHX = auxiliary solution heat exchanger; CON = condenser; EVA = evaporator; LDES = low-temperature desorber; LSHX = low-temperature solution heat exchanger; HDES = high-temperature desorber; HSHX = high-temperature solution heat exchanger. Figure 7: Singe-effect double-lift water/LiBr absorption cycle schematic of the absorption chiller developed by World Energy Co., Ltd. Adapted from Reference [36]. Note: AABS = auxiliary absorber; ABS = absorber; ABS-HX = absorber heat exchanger; ADES = auxiliary absorber; ASHX = auxiliary solution heat exchanger; CON = condenser; DES1 = first-desorber; DES2 = second-desorber; EVA = evaporator; LSHX = low-temperature solution heat exchanger; HSHX = high-temperature solution heat exchanger. In the nominal condition, the chiller delivered chilled water at supply/return temperatures of 8/13 \({}^{\circ}\)C with a thermal COP of 0.71 (type 2 ABH) using driving hot water at inlet/outlet temperatures of 95/55 \({}^{\circ}\)C (i.e., a driving heat temperature glide of 40 K). The cooling water inlet/outlet temperatures were 31/36.5 \({}^{\circ}\)C. The nominal cooling capacity of this chiller product covers the medium- to large-scale, between 105 and 4571 kW. To date, the total installed capacity of this chiller (product type 2 AB) is approximately 476.5 MW in South Korea and 47.6 MW in the rest of the world. It can lead to savings of 28 GWh of electricity per year and avoids 45 MW of power for peak demand in South Korea.