Thermochemical Storage for Air-Conditioning using Open Cycle Liquid Desiccant Technology E. Laevemann, M. Peltzer, A. Hublitz, A. Kroenauer, U. Raab, A. Hauer Bavarian Center for Applied Energy Research Walther-Meißner-Str. 6 85748 Garching, Germany
Outline Introduction System Description Component Development System Design and Installation Component Tests Summary and Conclusion
Thermochemical Storage for Air-Conditioning using Open Cycle Liquid Desiccant Technology Regenerator Regeneration Temperature 60-80 C Coefficient of Performance COP > 1 Collector Array Energy Storage Absorber Air Cooler Theoretical Energy Storage Capacity 270 kwh/m³ Indirect Evaporative Cooling Systems
Energy Storage for Air Dehumidification, Theoretical Boundary Ideal Cooled Absorption Boundary Conditions Dehumidification [g/kg] 15 10 5 0 Dehumidification Energy Storage Capacity 0 0 50 100 150 Mass Flow Ratio Air to Solution [-] 1800 1200 600 Energy Storage Capacity [MJ/m³] Outside Air Temperature 32 g/kg Wetbulb 23.9 C Inlet Concentration Solution : 40 % Best Mass Flow Ratio for Dehumidification and Energy Storage
Low Regeneration Temperatures by Means of an Internally Cooled Absorption Temperatures [ C] 100 80 60 40 20 Treg,min Treg,min Inlet Air Cooling Water Solution 0 0 4 8 12 16 20 Air Humidity Ratio [g/kg] Air Internally Cooled Absorber Mass Ratio Air/Sol. 60 100 Specific Solution Flow 0.2 0.4 l/(hm²)
Demonstration Project TCS-4 Project Description Duration January 2004 - January 2006 Budget ca. 200 000 EUR Objectives Further Development of Absorber & Regenerator Technology Energy Storage Technology Indirect Evaporative Coolers Demonstration of the State of the Art of Liquid Desiccant Cooling Cooling of the Jazz Club Unterfahrt
Demonstration Project TCS-4 Project Partners Building Owner Future Building Owner Provider Indirect Evaporative Coolers Provider Absorber/Regenerator R&D, Project Management Financial Support Münchner Gesellschaft für Stadterneuerung State Capital München Howatherm Klimatechnik GmbH, Brücken L-DCS Technology GmbH, Ismaning ZAE Bayern e.v. Federal Department of Labor
System Description TCS-4 18 C Jazz Club Fan Coil Units 26 C Absorption Mode Return Air 26 C 12 g/kg 15 C 20 C Absorber Regenerator HX1 IEC1 HX2 IEC2 25 C, 5 g/kg Exhaust Air 25 C 20 g/kg 22 C 30 C 32 % 42 % Desiccant Storage HX3 District Heating
System Description TCS-4 Jazz Club Fan Coil Units Regeneration Mode Return Air Absorber Regenerator 30 C, 24 g/kg HX1 IEC1 HX2 IEC2 Exhaust Air 26 C 12 g/kg 30 C 24 g/kg 75 C 55 C 42 % 32 % Desiccant Storage HX3 District Heating
Component Development & Installation: Absorber/Regenerator Unit Distributors for Liquid Desiccant Heat and Mass Transfer Plates Cassettes
Component Development & Installation: Absorber/Regenerator Unit Absorber/Regenerator Unit
Component Development & Installation: Liquid Desiccant Piping and Storage System
Component Development & Installation: Liquid Desiccant Piping and Storage System
Component Development & Installation: Static Mixer for Dew Point Measurements
Installation: Indirect Evaporative Cooler and Hydraulics
Installation: Fan Coil Units in the Jazz Club
Calculated Design Point Performance: Indirect Evaporative Cooler A1 WÜ1 A2 VK2 WÜ2 A3 A4 30 0.2 0.4 0.6 P1: Cooling Potential without Cold Recovery P2: Cooling Potential with Cold Recovery Temperature [ C] 25 20 15 10 A1 Air A2 10 C Fan Coil Unit P2 A4 A3 P1 F1 F2 W2 15 C Water 0.8 20 C W1 Pressure = 95.0 kpa 5 C 5 0.000 0.002 0.004 0.006 0.008 0.010 0.012 0.014 0.016 Humidity Ratio [kg/kg]
Component Test: Indirect Evaporative Cooler A1 WÜ1 A2 VK2 WÜ2 A3 A4 Results Wetted area provides good evaporative cooling Only 15 % of the heat transferring area are wetted (meets expectations)
Component Test: Absorber 22 C 30 C Results Air dehumidification is almost isothermal. In first performance tests, only 50 % of the dehumidification aimed at was experimentally reached. Realized Energy Storage Capacities: 67-85 kwh/m³
Summary and Conclusion A demonstration plant for the state of the art of liquid desiccant cooling has been built up. The jazz club can be cooled. The performance of the controls and the measurement accuracy is good. The plant has proved to be an excellent facility for performance tests of the components absorber, regenerator and indirect evaporative coolers The performance of the indirect evaporative cooler and the fan coil units is close to what has been expected. In the first tests, the absorber-regenerator-unit did not yet achieve the intended performance. The wetting of the exchange surfaces (20-40 %) of the tested, commercially available devices is far below what has been reached in laboratory (> 90 %). An improvement in surface wetting would be a major step towards favorable economics of this technology.