Which of the following factors can affect the efficiency of a refrigeration system?

The efficiency of a refrigeration system is significantly influenced by the temperature of the environment. When the external temperature is high, the system has to work harder to remove heat from the refrigerant, which can lead to increased energy consumption and reduced efficiency. In contrast, a lower ambient temperature can assist in the heat exchange process, allowing the system to operate more efficiently.

While color can play a role in heat absorption and reflection, especially in specific conditions, it is not a primary factor affecting the overall efficiency of refrigeration systems. The size of the components can impact system performance, but it's more about the correct sizing rather than size alone, which may not directly correlate with efficiency. Insulation is crucial for minimizing heat transfer in and out of the refrigeration system, influencing its efficiency, but it doesn't have as direct an impact as the surrounding temperature.