Volume 54

Novel operational strategy for operating a hybrid mechanical compression and adsorption based chiller Vivek Kumar Mishra, Samir Nanda, Sourav Mitra

Abstract

Catering to variable load has been a big challenge for large chillers for air-conditioning and process cooling applications. Traditionally chillers were designed for catering to peak capacity with hot-gas bypass being the most common technique for capacity control in fixed speed operation. In more recent applications variable speed compressors have been the preferred choice. In this study we propose a novel hybrid system which combines the mechanical and thermal compression techniques for producing chilled water. The mechanical compression caters to steady load whereas the adsorption based thermal compression caters to variable load. The refrigerant used in this study is R134a with coconut shell based activated carbon as the adsorbent. The adsorber connects to evaporator under peak load operation whereas it regenerates during low load condition thereby keeping the chilled water outlet temperature nearly constant. Experiments are conducted on a lab-scale 1 RTon system. The proposed operational strategy has the potential to handle up to a 26% variation in refrigeration load on the evaporator for maximum regeneration temperature of 850C for the adsorbent.

Keywords vapor compression systems, adsorption cooling, activated carbon, hybrid cooling system