An old fridge without a compressor cannot be used as a deep freezer, even if there is no food inside. The cooling system of a refrigerator is designed to maintain a temperature above freezing (typically around 35°F to 40°F or 2°C to 4°C) to keep food fresh. It uses a compressor to circulate refrigerant and remove heat from the interior.
On the other hand, a deep freezer is designed to reach and maintain much lower temperatures, typically well below freezing (around 0°F or -18°C). It has a more robust cooling system and insulation to keep the interior cold enough to freeze and store food for an extended period.
Since an old fridge lacks the necessary cooling capacity and insulation for deep freezing, it will not be able to maintain the required low temperatures needed for preserving food. Additionally, using a fridge in this way could strain its components, potentially leading to malfunction or damage.
If you need a deep freezer for storing food, it's best to invest in a proper deep freezer designed for that purpose. They are more energy-efficient and better equipped to handle the freezing temperatures required for preserving food safely.