Is colder chilled water always better? For a chiller, when other conditions are similar, making the water less cold allows a higher evaporating temperature, and the compressor usually works less. But for a room, the coil surface must be below the air dew point for moisture to condense; once the water temperature rises, whether cooling and dehumidification can keep up at the same time is the unavoidable issue in actual operation.
Comfort office buildings can re-match the cooling source, terminals and controls for medium-temperature water. Process dehumidification workshops often take another, more power-consuming path: using low-temperature chilled water to subcool the air for dehumidification, then using a heater to raise the supply air temperature back up. Cooling and heating offset each other, and electricity costs and humidity targets often deteriorate together. The following is not a deduction of changing a building's setpoint from 7°C to 12°C, but a two-stage retrofit completed by NUNXIN in a customer's large dehumidification room, with data from the operating results summarized by the user.
I. Why was this large dehumidification room originally both humid and power-hungry?
The site is still using a first-generation, low-efficiency dehumidification system that has been in operation for about 23 years. Data for July 2025 provided by the user shows that combined power consumption reached a maximum of 674 kW, the overall average dehumidification compliance rate was only 49.6%, and two units were out of service at the time.
The causes can be seen from both the equipment and the design. In terms of operation, the chilled water flow rate and supply air velocity have deviated from the original design, batch dehumidification time has been stretched from 2 hours to 5 hours, and average humidity has risen from 45% to 52% (the standard for this room is 2 hours and 47%). In terms of design, this is a chilled water cooling plus electric rehea