Design Development and Performance Evaluation of Phase Change Material (PCM) based Chiller for Raw Milk Cooling

Abstract

The phase change material (PCM) based milk chiller was designed and
developed at ICAR-Central Arid Zone Research Institute (CAZRI), Jodhpur, India. The
performance evaluation of the developed box type well insulated chiller made of stainless
steel 304 (SS 304) was carried out experimentally for different eutectic solutions and
salt hydrate viz. potable water (PW), propylene glycol, diethylene glycol, triethylene
glycol, and ammonium chloride (NH 4 Cl) at different concentrations (5-30%) are used for
cooling energy storage. The initial temperatures of PW and propylene glycol at different
concentrations were 25.8°C. The final temperatures of PW and propylene glycol at
various concentration (5-30%) varies from -4.2°C to -14.9°C. The initial temperatures of
PW and diethylene glycol at different concentrations were 25.9°C. After freezing for 12
hrs the final temperatures at various concentration (5-30%) varies from -4.1°C to -17.8°C.
The initial temperatures of PW and triethylene glycol at different concentrations were
25.8°C. After freezing for 12 hrs the final temperatures at various concentration (5-30%)
varies from -3.9°C to -17.2°C. Similarly, the initial temperatures of PW and NH 4 Cl at
different concentrations were 25.8°C. After freezing for 12 hrs the final temperatures at
various concentration (5-30%) varies from -3.7°C to -16.0°C. The chiller reduced milk
temperature from 32.7°C to 11.4°C in about 120 minutes in case of PCM as potable water,
32.6°C to 9.1°C in case of PW with 10% propylene glycol, 32.5°C to 8.5°C in case of PW
with 10% diethylene glycol, 32.6 to 8.8°C in case of PW with 10% triethylene glycol and
32.5 to 9.3°C in case of PW with 10% NH 4 Cl concentration. The highest drop for PCM
(PW+10% diethylene glycol) came to 9.9°C in 100 min followed by 8.7°C in the next 40
min. The final temperature 10°C varied for about 2.5 hrs