How to choose a chiller?

Explanation Based on the Selection Form

1. Purpose of the Chiller:
   The use of the chiller will depend on the equipment or application. Broadly, there are two categories:
   1. For Specific Equipment (e.g., welding machines or laser processing machines): In this case, the chiller is connected to the equipment in a closed circuit. The chiller can be used in 1:1 configuration with the equipment or in 1:multiple configuration.
   2. **For a Process** (or multiple processes): This involves producing chilled water for specific processes (e.g., cooling water tanks for extrusion molding or food packaging). In this case, a separate water tank is used, and the chiller operates in an open circuit.

2. Chiller Tank Type: (Reference Page: Built-in Tank / Without-Built-in Type)
   - Built-in Type: Used for category 1 above.
   - Without-Built-in Type: Used for category 2.

3. Cooling Liquid:
   This refers to the water used in the chiller. Generally, clean water is recommended. Clean water includes RO water (reverse osmosis) or DI water (deionized). Tap water can be used for short-term applications, but it is not recommended for long-term use due to the accumulation of lime and other deposits in the heat exchanger, which can reduce cooling efficiency.
   Additionally, ultra-pure water with no impurities is also not suitable due to the risk of ion precipitation. Well water may also be corrosive depending on its composition, so it is not recommended. Each manufacturer has its recommended water quality in terms of conductivity and the ratios of various main components. If only tap water is available, water from drinking water dispensers installed in your factory can be acceptable.

4. Cooling Method:
   - Air-Cooled: Refrigerated chillers use refrigerants in the refrigeration cycle. They exchange heat with the surrounding air during the condensation process (condenser).
   - Water-Cooled: Water is used for heat exchange in the condensation process of the refrigeration cycle. This water is typically supplied from a cooling tower.
   Air-cooled chillers discharge heat (exhaust air) during refrigerant heat exchange in the condenser, and installation is usually outdoors. Water-cooled chillers, on the other hand, do not discharge much heat, allowing for indoor installation without issues.

5. Set (Target) Water Temperature:
   What temperature of chilled water is required for the target equipment or process? This is the temperature set on the chiller. Typically, it can be set between 5°C and 35°C. 
   Note: If the chiller's capacity is insufficient, the temperature set on the chiller may not be maintained under load, and the temperature will continue to rise.

6. Heat Generation of Target Equipment/Process:
   - If the target is equipment: Generally, the manual for the target equipment will provide information regarding the chilled water requirements (e.g., heat generation of 6.98 kW, supplying 20 L/min of chilled water at 25°C). If specific values are not listed, the following steps can be taken to calculate the heat generation:
   1. Measure the inlet and outlet temperatures of the chilled water and the flow rate.
   2. Calculate the heat generation based on the above data.

  Example:

- Chilled Water Inlet Temperature: 25°C
- Chilled Water Outlet Temperature: 30°C
- Flow Rate: 20 L/min

  (30-25)x(20x60) / 860 = 6.98kW

- If the target is a process: In this case, the chiller cools water from a separate tank (open circuit).
1. Measure the water volume in the tank, the initial water temperature, and the temperature after one hour.
2. Calculate the heat generation based on the above data.

Example:

- Water Volume: 500 L
- Initial Water Temperature: 30°C
- Water Temperature After One Hour: 50°C

   500x (50-30) / 860x1 = 11.63kW

7. Power Supply:
   The industrial power supply in Thailand is 3-phase 380V / 50Hz.

8. Ambient Temperature of Chiller Installation Location:
   For water-cooled chillers, the cooling tower water temperature is considered, which can typically only decrease by 3 to 4°C from the outside air temperature.