Load banks generate a lot of heat during operation. Effective heat dissipation methods are essential to ensure their performance, extend their service life, and ensure the accuracy of the test. Common heat dissipation methods are mainly the following:

Air cooling

Principle: Through fans and other equipment, air is forced to convect between the inside and outside of the load bank, so as to bring the heat generated by the load out of the bank.

Composition and working method:

Inlet and outlet design: Load banks are usually equipped with special inlets and outlets. Cold air enters from the inlet, absorbs the heat generated by the load, and becomes hot air and is discharged from the outlet. For example, an inlet is set at the bottom of the bank and an outlet is set at the top. The principle of hot air rising is used to accelerate air circulation with the assistance of fans.

Fan configuration: including axial fans and centrifugal fans. Axial fans are generally installed at the inlet or outlet. They can generate a large amount of air, allowing air to flow along the axial direction and quickly take away heat. Centrifugal fans can throw air radially, which is suitable for occasions that require higher wind pressure. They can more effectively overcome the resistance of the air duct and ensure that the air circulates evenly in the complex structure inside the bank. For example, some large load banks will install multiple axial fans on the side or back to meet a large number of heat dissipation needs.

Advantages: relatively simple structure, low cost, easy installation and maintenance, suitable for most medium and small power load banks and occasions where heat dissipation requirements are not extremely high.

Disadvantages: The heat dissipation efficiency is relatively limited. Under high power density or high ambient temperature, it may not meet the heat dissipation requirements. And the fan operation will generate a certain amount of noise.

Water cooling

Principle: Use water as a cooling medium to take away the heat generated by the load through a circulating water circuit. Water has a large specific heat capacity and can absorb a large amount of heat while its own temperature rise is relatively small, thereby achieving efficient heat dissipation.

Composition and working method:

Cooling water pipeline: Inside the load bank, a cooling water pipe is arranged near the heating element. The water pipe is usually made of metal with good thermal conductivity, such as copper pipe. When hot water flows in the pipe, it transfers heat to the pipe wall, and then to the surrounding air or cooling medium.

Circulation system: It consists of a water pump, a water tank, a radiator, etc. The water pump pumps the cold water in the water tank into the cooling water pipeline in the load bank, absorbs heat and turns into hot water, then flows to the radiator, where it exchanges heat with the outside air, and the cooled water flows back to the water tank, and the cycle repeats.

Advantages: High heat dissipation efficiency, can take away a lot of heat, suitable for high-power load banks and occasions with strict heat dissipation requirements. In addition, the water cooling system has relatively low noise during operation.

Disadvantages: The system structure is complex, the cost is high, special water circuit design and maintenance are required, and there is a risk of water leakage. If water leakage occurs, it may cause serious damage to the load bank and internal equipment.

Heat pipe heat dissipation

Principle: The heat pipe is a heat transfer element with extremely high thermal conductivity. It uses the phase change (evaporation and condensation) of the internal working fluid to transfer heat. When one end of the heat pipe is heated, the working liquid evaporates quickly, and the steam flows quickly to the other end under a small pressure difference. After being cooled at the cold end, it condenses into liquid and releases a large amount of latent heat. The liquid then flows back to the hot end through capillary action or gravity, and the cycle achieves efficient heat transfer.

Composition and working method: In the load bank, the evaporation section of the heat pipe is in close contact with the heating element to absorb heat, and the condensation section exchanges heat with air or other cooling media through heat dissipation fins and other methods. For example, the evaporation section of the heat pipe is buried in the resistance load, and the condensation section extends out of the bank to cooperate with the external air cooling system, which can quickly transfer the heat inside the load to the outside.

Advantages: The heat dissipation efficiency is extremely high, and the heat can be quickly transferred from the heat source. The heat pipe itself has a simple structure, small size, light weight, and does not take up too much space.

Disadvantages: The manufacturing process of the heat pipe is relatively complex, the cost is high, and once the heat pipe is damaged, it is difficult to repair.

Air conditioning refrigeration and heat dissipation

Principle: Similar to the refrigeration principle of ordinary air conditioners, through the cyclic phase change of the refrigerant, the heat in the load bank is absorbed and discharged to the external environment, thereby reducing the temperature inside the load bank.

Composition and working mode: It is mainly composed of a compressor, a condenser, an evaporator, a throttling device, etc. The compressor compresses the gaseous refrigerant into a high-temperature and high-pressure gas and sends it to the condenser. In the condenser, the refrigerant dissipates heat to the outside world and becomes liquid. The liquid refrigerant enters the evaporator after being reduced in pressure by the throttling device, absorbs the heat in the load bank in the evaporator, re-vaporizes into a gaseous state, and then returns to the compressor, so that refrigeration is achieved in this cycle.

Advantages: It can accurately control the temperature inside the load bank and maintain a stable working environment. It is suitable for high-precision test load banks with extremely strict temperature requirements.

Disadvantages: The equipment cost is high, the operating energy consumption is large, and the air conditioning system needs to be maintained regularly to ensure its normal operation.