Innovative Components for Additional Heating Systems Dipl. Ing. Frank Wolf Dipl. Ing. (FH) Norbert Tessendorf Phone: 0043 - (0) 5577-62370 Fax: 0043 - (0) 5577-623709 Mobile: 0043 - (0) 664-1019620 Em@il: oe@obrist.at
Content Introduction Concept Realization Tests conducted Results on 1 st prototype Next steps
Introduction Issue 1 A/C operation leads to moisture and/or water storage on the evaporator Microbial cultivation Creation of odor Surface treatments Water drop spatter
Introduction Issue 2 Waste heat deficiency Additional heating required (e.g. FFH, electrical, etc.) R744 has the potential to be used not only for A/C but also for additional heating operation (e.g. HP or HG) Direct system heat exchanger needed in the cabin HG heat exchanger can be low pressure HP heat exchanger is high pressure side
Introduction Issue 1 and 2 For flash fogging reasons such a system would need a 2 nd heat exchanger: one for AC, one for HG The need of an extra heat exchanger causes: Increased packaging space for the HVAC-unit Airflow and distribution issues Additional costs caused by supplemental components Extra weight
Airside Low Cost CO 2 A/C & Heating System AC-Orifice Front HVAC CO2 Heater Main Heater Evaporator Air Accumulator CO2 IHX THST Engine Radiator Gas Cooler Air HG-Orifice Main Coolant Pump CO2 ECVDCompressor HP 3/2SV
Airside Low Cost CO 2 A/C & Heating System HG-Orifice AC-Orifice CO2 IHX Front HVAC Main Heater Evaporator Air Accumulator THST Engine Radiator Gas Cooler Air Main Coolant Pump P/T CO2 ECVDCompressor HP 3/2SV
Concept Finless design (no secondary heat exchange surface) Parallel arrangement of MC-tubes Increase of the primary heat exchange surface by: Increasing the number of MC-tubes Implementation of preformed MC-tubes
Concept In & Outlet Manifolds Preformed MC-tubes
Concept Advantages Optimized drainage & reduced storage of moisture Preformed MC-tubes: Enhanced conditions for airside heat exchange Improved performance of evaporation Locally reduced velocities for AC and HG lead to an excellent NVH behavior Minimized airside temperature spread through refrigerant distribution management giving access to a low T even under inhomogeneous airflow distribution situations Increased dynamic and performance of the A/C and heating system Single A/C-additional heating-system cabin heat exchanger (only one)
Realization Theoretical calculation and simulation of the evaporator Manifold layout & design Tooling for preformed MC-tubes Assembly & process investigation Brazing process: NOCOLOK Surface treatment investigation
Tests Conducted Burst pressure & operating pressure test Cooling capacity (air side & refrigerant side) Pressure drop (both sides) Temperature spread of the evaporator at different air flow rates Water retention
Results on 1 st Prototype Burst pressure & operating pressure test Initial burst pressure was 108 bar.
Results on 1 st Prototype max. cooling capacity [kw] 12 10 8 6 4 measures: MC-tube homogenity optimisation Preformed MC-design improvement 2 0 best in class simulation finless 1st prototype target 2nd prototype
Results on 1 st Prototype airside pressure drop [Pa] 140 120 100 80 60 40 20 measures: MC-tube homogenity optimisation Preformed MC-design improvement 0 best in class simulation finless 1st prototype target 2nd prototype
Results on 1 st Prototype Water retention test procedure Component is completely submerged in water Drainage time 1 st prototype: <<1sec Water retention [g] 350 300 250 200 150 100 50 0 best in class 1st prototype target 2nd prototype
Outlook ¾ Improved design realized with 2nd prototype ¾ Evaluation process ongoing Cooling capacity and pressure drop Temperature spread System testing NVH Automotive standards ¾ Marketing Interest on OEM side Licensing to system & heat exchange suppliers Development project
Airside Low Cost CO2 A/C & Heating System HG-Orifice AC-Orifice P/T Air THST Engine Control Unit Radiator Main Heater Main Coolant Pump Gas Cooler CO2 IHX Front HVAC Air