ZL-25T 25 Ton Industrial FRP Counter Flow Cooling Tower - Engineering Specifications

25 Ton Cooling Tower Technical Specifications and Application Details

The ZL-25T FRP counter flow cooling tower delivers 87.92 kW heat rejection at 25 refrigeration tons with 19.51 m3/h water flow rate. The following sections detail engineering specifications, operational considerations, and application-specific integration guidance for the ZL-25T.

Heat Duty Calculation: 25 Ton = 87.92 kW at 19.51 m3/h Flow Rate

The 25-ton ZL-25T is rated at 87.92 kW of heat rejection under CTI STD-201 design conditions (95°F inlet water, 85°F wet-bulb, 5°F range). The flow rate of 19.51 m3/h is calibrated to a 5°C temperature drop across the fill media, which is the standard range for induced-draft counter-flow cooling towers. At this flow rate, the ZL-25T delivers exactly 87.92 kW of heat rejection when the leaving water temperature reaches 32°C against a 27°C wet-bulb. For applications requiring higher temperature drops (8-10°C), the tower can accept lower flow rates while maintaining the same 87.92 kW heat duty, provided the wet-bulb approach stays within 5°C of design. This makes the ZL-25T suitable for medium commercial buildings (800-2000 m²), 200-350 ton injection molding, mid-size data centers, regional hospitals where standard HVAC loop conditions apply.

Wet-Bulb Approach: Why 8 deg C is the Engineering Performance Metric

The wet-bulb approach is the most critical performance metric for any cooling tower. It represents the difference between the leaving water temperature and the ambient wet-bulb temperature. Under standard design conditions (27°C WB), the ZL-25T achieves a 5°C approach, meaning the leaving water reaches 32°C. As ambient conditions deviate from design, the approach varies predictably: at WB 24°C the leaving water drops to 29°C; at WB 30°C (hotter climate) the leaving water climbs to 35°C; at WB 21°C the leaving water drops to 26°C. The ZL-25T's 200 CMM airflow at 770 mm fan diameter is specifically sized to maintain this 5°C approach across the expected operating range. Off-design performance is documented in CTI thermal performance curves and is reproducible year-over-year when water flow and chemistry remain within design limits.

Counter Flow Geometry: Vertical Air Distribution in 1380mm Diameter Tower

The ZL-25T uses counter-flow geometry where water falls downward through the fill media while air rises upward through the same media. This counter-flow arrangement provides 15-20% better thermal performance than cross-flow designs at the same airflow rate. The tower diameter of 1380mm and height of 1900mm are optimized for the 19.51 m3/h water flow rate: the diameter provides sufficient cross-sectional area for 200 CMM airflow to reach every part of the fill media, while the height ensures water spends adequate residence time in contact with the rising air stream. PVC film fill media is standard for low-fouling operation, with optional cellular drift eliminators reducing drift loss to 0.005% of circulating flow (less than 10 L/h for the ZL-25T).

Fan Performance: 200 CMM at 770 mm Diameter Propeller

The ZL-25T's axial fan delivers 200 CMM of airflow at design conditions, driven by a 0.75 kW motor at 380V 3-phase 50 Hz. The 770mm propeller diameter is sized to move 200 CMM against the 16 kPa external static pressure of the fill media and drift eliminators. Fan tip speed is kept below 60 m/s to minimize noise (the ZL-25T operates at 60-65 dB(A) at 5 meters) and to extend bearing life beyond 50,000 hours. Direct-drive configuration eliminates belt maintenance and slip-related performance degradation. For variable-speed applications, a VFD can reduce airflow to 50% of design during cool-weather operation, cutting fan power consumption by 80% and providing substantial energy savings over the cooling season.

Head Loss Curve: 16 kPa at Design Flow and Pump Sizing Implications

The ZL-25T's 16 kPa head loss at design flow (19.51 m3/h) is the external static pressure that the chilled water pump must overcome, in addition to the chiller evaporator and piping losses. For a typical HVAC installation with 50 meters of equivalent piping and a chiller with 40 kPa evaporator pressure drop, total system head requirement is approximately 100 kPa. The ZL-25T's 16 kPa contribution is moderate, allowing standard end-suction pumps at 50 Hz operation. Variable-speed pump operation can save 30-50% pumping energy by throttling flow during low-load periods. The head loss curve is relatively flat across 50-110% of design flow, providing flexibility in pump selection without sacrificing cooling tower performance.

FRP Material Selection: 98 kg Dry Weight and 15-Year Service Life

The ZL-25T shell is constructed from fiberglass-reinforced polyester (FRP) with UV-stabilized gelcoat surface, providing 15-20 year service life in outdoor environments. Dry weight of 98 kg and operating weight of 500 kg (when filled with water) require a flat concrete pad capable of supporting 550 kg per square meter. The ABS fan is corrosion-resistant and balanced to ISO 1940 G6.3 standard. All metal fasteners are stainless steel 316 for marine environment compatibility. Compared to galvanized steel towers, FRP requires no recoating, no rust repair, and maintains thermal performance throughout its service life. The ZL-25T's FRP construction is CE certified for European installations and IP55 rated for the electrical motor enclosure.