How should a properly designed electric defrost operate to melt ice?

A properly designed electric defrost system should operate from the bottom to the top of the evaporator to effectively melt ice. This method utilizes the natural tendency of heat rising, which enhances the efficiency of the defrosting process. When heat is applied at the bottom of the evaporator, it causes the ice to melt and the moisture to flow downwards, allowing for better drainage and preventing re-freezing in cooler areas of the evaporator.

Operating from the bottom to the top ensures that the ice is melted in a controlled manner, addressing the coldest points first and gradually allowing the warmer air to rise and continue to apply heat to the remaining ice. This staggered approach optimizes the defrost cycle, resulting in efficient operation and minimizing energy use.

In contrast, other directional approaches, such as operating from the top to bottom or sideways (left to right or right to left), would not take advantage of the natural convection currents and could lead to uneven melting or excessive run times. This could ultimately impair system performance and increase maintenance issues.