Cooling water temperature of the unit is very important that if the temperature rises up then some problems starts by time during the manufacturing. To avoid this, a chiller unit is necessary.

The cooling water temperature level directly effects the quality of the end product. By the increasing water temperature, the end product quality becomes poor.

Usage areas of chiller systems

• Cooling of injection press molds
• Jaw and transformer cooling of spot welding machines
• Cooling of torches of gas welding robots
• Oil cooling of hydraulic presses
• Cooling of seam welding machines
• Acid bath temperature is kept constant between 20-30 C such as galvanizing and anodizing processes
• MCooling of the servo motor shaft of router benches in furniture industry

Heat Exchanger (evaporator) Types and Differences

• Shell and Tube (pipe type)
• Plate type
• Coaxial type
• Immersion type
• Spiral pipe type
• The differences between the above varieties are described according to the following criteria.
• Heat Transfer Efficiency, Desired Minimum Water Quality Measure, Ease of Maintenance and Space Requirement

Plate type heat exhangers has the highest efficiency due to the compact structure. Shell and tube heat exchangers are in second place in the ranking. The lowest in efficiency is the spiral type heat exchanger. The efficiency in heat transfer is directly proportional to the heat transfer area. As the amount of surface where heat transfer takes place decreases, larger volume exchangers are necessary to achieve the same capacity.

Spiral tube heat exchangers are in the simplest structure. This type of heat exchanger is the easiest to maintain since access can only be done by opening the tank cover. Shell and tube heat exchangers cannot be removed and cleaned. But with acids and chemicals cleaning facilities are available. So it is difficult to maintain. Plate type heat exchangers are divided into two types. Since the welded types cannot be removed, their cleaning is the same as the shell and tube type. In sealed types, the plates are disassembled because they are connected to each other with gaskets between them.

Water quality is very important for plate and shell & tube heat exchanger models. This is because they cannot be removed for maintenance easily. In other heat exchanger models, the quality of process water is not important.

Plate type heat exchangers occupy the least area. There is no water tank in plate type model chiller devices. Therefore, this type of chiller cooling devices are more compact. Chiller machines that use other type of heat exchangers are larger in size.

Installation Tips for Chillers

The installation area of ​​the chillers should be well ventilated. If ventilation is not good then an air exhaus duct should be mounted in order to remove hot air from the room.

The distance between the chiller and the side walls should be at least 1 meter. This is both ease of maintenance and to provide enough space for inlet air to the fans

The strength of the concrete on which the cooling unit will be mounted should be strong enough to carry the load. If the concrete surface is not flat and durable, vibration may occur during operation.

Power lines should be provided before the installations in accordance with the specifications written in the technical specification of the chiller units.

Usage of Water Filter and Manometer

It is recommended to put a water filter at the tank inlet İf the quality of process water is not good

Process Water Circuit and Compensator Usage

The placement of the water pump relative to the water tank should be as in the picture on the right. As can be seen in the Picture, the inlet of water into the suction line of the pump is close to the bottom of the tank. Vibration dampening compensators should be used in very large cooling circuits.

Air and Water Cooled Chiller Differences

Chiller cooling devices are divided into two categories as air and water cooled according to the type of condenser where the excess heat is removed from. In air-cooled models, it is the air circulation passing through the condenser that liquefies the heated gas. However, in water-cooled models, the hot gas coming into the condenser is cooled by water.

Now let’s look at the differences of air and water cooled chiller devices.

Cooling of hot gas with water provides to reach lower condensation temperature compared to air cooling. Therefore performance and efficiency will be higher in water cooled models.

There should be ventilation system in the place where the air cooled chiller models will be mounted beacuse of the excess heat of the refrigerant exhausted to the outside environment through the aluminum fin plates. If there is no ventilation, the outdoor environment gets very hot and this hot air cannot cool the refrigerant and the capacity decreases. In water-cooled systems, since the refrigerant is cooled with water, ventilation is not necessary in their environment.

Since air-cooled models have to use aluminum finned condensers, they are larger than water-cooled models.

In air cooled devices, there is only piping between the system that is intended to be cooled and the chiller. However, in water-cooled systems, piping is also required between the condenser and cooling tower.

Fort the air cooled industrial chiller devices the contamination of the condenser causes the cooling capacity to decrease. When this is detected the condenser is very easy to clean. However, water-cooled devices are difficult to detect the contamination and cleaning, and also professional equipment is required for detection and cleaning.

Air cooling industrial cooling chillers are more cheaper than water-cooled models. This is because the water cooling chiller devices need a cooling tower to work, which is an extra expense. In addition, maintenance costs of water-cooled chillers are higher.

Chiller Cooler Selection Capacity Calculation

The Formula Q=C*M*△t is used for heat load calculation. If we want to decide to cool an existing unit with chiller, we first need to calculate the heat load generated by our exisiting unit (units such as plastic injection, wire erosion, spot welding, CNN oil cooling, welding robot torches, presses etc.) while operating at maximum capacity. In order to make this calculation, we use the formula given above.

1. Q : Heat Load (Joule)
2. C : Speific Heat (Joule/gr x oC) : It is the amount of heat required to increase the temperature of 1 gram of a substance by 1 C.
3. M : Mass(gr)
4. △t : Temperature difference of the liquid to be cooled.

Let’s look at what to do step by step to calculate the heat load Q:

It is essential to measure how much water is circulating in the unit to be cooled. We can do this as follows. First we need to take a water tank of known volume. Then measure the time when filling the water into the tank. Then we should calculate the water flow rate.

In this step, the temperature of the water entering and leaving the system is measured and noted.

After determining the water flow rate and △ t temperature difference, we can proceed to the heat load calculation. For example, you calculated the water flow as 1000 gr / second. You also calculated the delta t value as 5 C. Let the liquid you want to cool be water. If we use the formula accordingly:

1. Q : c*m*△t
2. Q : 4,187 (joule /gr0C)x 1000 (gr/sn) x (50C) (for water)
3. Q : 20.935 Joule/Minute
4. Q : 20.935 Watt = 20,935 kW