The Water Audit portion of the Federal Energy and Water Audit Report may be used to collect data to reflect a building’s water usage and recommendations for improvement. Input data fields for Cooling Towers and the guidance listed here were derived from Section 3.5 of the Water Evaluation Tools Handbook.
Cooling towers (see Figure 28) dissipate heat to the ambient air from recirculating water used to cool chillers, air conditioners, and other process equipment.9 The following information describes the data to be collected during a cooling tower walk-through survey. Some of the information can be gathered by looking at the key components of the system, including the cooling tower(s), chillers and heat exchangers, and piping configuration and pumps. However, most of the information listed below will need to be gathered from control systems connected to the cooling system and/or from interviews with the facility operations and maintenance staff.
Data Collection for Cooling Towers
If the campus has cooling towers that are metered, document the location and information on who is responsible for the meter so the data can be requested at a later time. For cooling towers that are not metered, collect the information needed to estimate water use.
- Cooling Tower Name -- The tool allows for multiple cooling towers to be entered; therefore, a unique name must be identified for each facility (such as building name/number associated with the facility).
- For what process is the cooling tower used? -- Identify the process the cooling tower serves, such as comfort cooling (heating, ventilation, and air conditioning [HVAC]), process load, or other.
- Is makeup water use metered? – Yes/No
- Total Tonnage of Chillers Associated with the Cooling System -- Obtain the system tonnage from the nameplate on the chiller system or from the manufacturer’s specifications.
- Typical Operating Cycles of Concentration of the System -- Ask the operator whether the system operates under a set number of cycles of concentration (CoCs). CoC is the ratio of the concentration of dissolved solids in the blowdown water compared to the makeup water, which is approximately equal to the ratio of volume of makeup to blowdown water. CoC is an important parameter in understanding how efficiently the system runs.
- Cooling Season Start and End Date -- Ask the system operator when the cooling season starts and ends for the system.
- Typical Number of Hours System Operates per Day -- Record the number of hours the system typically runs per day during the operating season. It is important to gather information on the operating time because it is used to determine what percentage of a full year (8,760 hours) the system operates, a key to estimating cooling tower water consumption. Operational information can be gathered from operating logs or connected controls systems.
- Typical Percent of Capacity Utilized over the Cooling Season -- Estimate the percent of total capacity that the system utilizes, on average, throughout the cooling season.
Repeat the data entry process above until all cooling tower systems have been input.