Vaccine transport requires a temperature range between 2 to 8°C. Constant and steady cooling in the above temperature range is required during the transportation of vaccines. The vaccine storage requires an efficient thermal management system for the depository of vaccines. The phase change materials can store and release more energy during latent heating regions than other materials that undergo sensible heating and cooling. The energy storage characteristics of phase change materials (PCMs) are employed to transport vaccines efficiently, without the constraints of traditional cold chain transport systems. The operating temperature of the cold storage box and financial limits determine which PCM is used. Polyethylene glycol (PEG 400) was selected as PCM for cold storage in the present study. However, PCMs generally have low thermal conductivity, which is not ideal for energy storage. To combat this, nanoparticles are added, which improve the heat conductivity of the PCM basis without significantly changing the material's unique features. The additive SiO₂ is used with copper nanoparticles to enhance thermal conductivity. The Differential Scanning Calorimetry test is done to find the melting point and latent heat. This paper reports the results of experimental investigations carried out to find the thermal performance of a cold storage box of PEG400 with nanoparticles. The nano-enhanced PCM (NePCM) cold storage box can maintain thermal management in cold storage between a safe range for multiple hours of transportation without providing any external power supply. The heat sink system was experimentally tested for its thermal performance and effectiveness.