Armfield

• Air flow rate on the performance of a cooling tower 
• Water flow rate on the performance of a cooling tower
• Water temperature on the performance of a cooling tower
• Cooling load on the performance of a cooling tower
• Packing density on the performance of a cooling tower
• Packing height on the performance of a cooling tower
• Operation at constant power (constant cooling load)
• Operation at constant water temperature
• Energy and mass balance across the air and water streams

The UOP6-MkII comprises a cooling tower mounted on top of a heated water reservoir. The cooling tower is manufactured from clear acrylic for visibility, and has an easily removable front face to allow different packing materials to be inserted. Two blocks of different density material and two blocks at reduced height are supplied as standard, but other material can be used for more advanced investigations.

The supplied material is in robust, preformed blocks encased in clear plastic which are easy to handle and store. Water is pumped from the reservoir to the top of the tower using a variable-speed pump. An array of spray nozzles ensures an even distribution of the water throughout the column section. As the water descends through the packing material it is cooled by the air flow from the variable-speed fan, which blows air upward through the tower.

Measurements of temperature and RH of the air at the inlet and outlet of the packing allow the change in moisture content of the air to be derived and the mass transfer due to the evaporative cooling to be calculated. The water is heated by an electrical heater in the sump tank. This can be operated in a closed loop mode to control the water at a specific temperature, or it can be operated at a user-defined power (continuously variable across the range) to simulate a fixed-load system.

All controls and displays are incorporated in the software supplied with the unit. This can be run on any modern Windows PC (not supplied) and communicates to the hardware using the integral USB interface. From the software it is possible to change the pump and fan speeds, to control the heater and to display all the sensor values. An optional Packing Characteristics Accessory UOP6-MkII-23 is available. This comprises a section of the standard packing, mounted to a replacement front panel. At three equidistant points within the packing, instrumentation is fitted to measure the water temperature, the air temperature and the RH of the air. This option is supplied with its own electronic interface module and requires a second USB port on the computer.

• • Water inlet at top of tower
  enlarge
• Measurements, computer control and data logging via USB port
  as standard
• Closed loop PID control of water temperature at entry to the tower for more versatile operation and more accurate results
• Four interchangeable sections of tower packing
  material supplied
• Two densities of packing material included for comparison
• Three different heights of packing can be compared
• User supplied material can easily be fitted into the tower
  for project work
• Uses true industrial packing material for more representative demonstrations
• Improved distribution of water onto the packing using an array of spray nozzles
• Electronic (software) control of water recirculation, air flow and heater power
• Electronic sensors measure flow of air and water, temperature of air and water and humidity entering and leaving the packing
• Modern electronic humidity sensors utilized, eliminating the need for high maintenance wet and dry bulb thermometers
• Water loss due to evaporation measured electronically
• Can be operated as a simple spray tower with no packing installed
• Optional Packing Characteristics Accessory UOP6-MKII-23 connected via second USB to temperature and humidity sensors

Electrical supply:

Demineralised water

UOP6-MkII-A
UOP6-MKII-B
UOP6-MKII-G

UOP6-MkII-23: Packing Characteristics Assembly

Windows PC (not supplied by Armfield), running Windows 98 or above with a USB interface. The software is provided on a USB.