It is important to maintain regular temperatures inside cold storage facilities and cold transport vehicles. During storage and transportation of temperature sensitive products, significant temperature variations may occur due to frequent door opening and closing of the cold storage facility.
It is the objective of this work to look into possible means of minimizing temperature fluctuation in cold stores by the application of phase change material (PCM) and look into the effect of door openings and defrosting.
In this work, a domestic freezer has been used to conduct experiments. Ammonium chloride aqueous solution was used as the PCM, and was placed into anodized aluminium panels. These panels were then placed against the internal walls of the freezer. Testing was done with and without the PCM filled panels inside the freezer, and consisted of door openings and activating defrost cycles. Experiments were conducted in an environmental chamber set to give a constant ambient temperature of 25 ºC and a relative humidity of 60%.
A regime incorporating 13 door openings and a defrost cycle over an 11 hour period was conducted to investigate the performance of including PCM into the freezer. Over the 11 hour period, the freezer air temperature remained fairly stable with PCM, in comparison to the air temperature without PCM.
It was found that the application of PCM into cold storage applications can help to minimise temperature variations during introduction of heat loads which will lead to more stable product temperatures.