This system operates continuously to freeze large volumes of product, generally large pieces such as whole chicken. They are designed with robust cooling systems that operate with recirculated ammonia and high speed evaporators and low air temperature. The trolley freezer uses a mechanical traction system anchored to the floor that allows the movement of carts or shelves where the product to be frozen is placed. The travel time of the carts within the trolley depends on the desired temperature and the conditions of the product such as weight, entry temperature, type of packaging, etc.