Run-Around Membrane Energy Exchanger Prototype 4 Design and Laboratory Testing

Abstract

The run-around membrane energy exchanger (RAMEE) is a novel design that utilizes a membrane and a liquid desiccant to transfer heat and moisture between remotely located ducts. A laminate membrane called AY Tech ePTFE (expanded polyetrafluoroethylene) was sourced based on the vapour diffusion resistance (VDR), liquid penetration pressure (LPP), modulus of elasticity (E), and price. The measured VDR, LPP and modulus for the AY Tech. membrane were 97±11 s/m, >82 kPa, and 387±32 MPa respectively. A laboratory model of RAMEE prototype 4 was constructed using the AY Tech. membrane. The effectiveness of the laboratory model was evaluated using the energy exchanger test facility. Airstream temperatures and relative humidity’s were measured at various location to determine the exchanger effectiveness. The highest total effectiveness values measured for prototype 4, at AHRI test conditions, were 52±16% and 47±7% for a net transfer unit (NTU) of 12.3 and a NTU of 5.0 respectively.