| DESIGNING CIRCULATION SYSTEMS WITH EFFICIENCY IN MIND |
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| Swimming pools are often designed without full consideration of the system’s fluid mechanics. For instance, a pool with a large pressure drop or an oversized pump will not operate at peak efficiency. Typically, this will not create any problems for the facility other than the fact it is wasting energy unbeknownst to the facility manager. To ensure the swimming pool operates efficiently, the first place to start is with a properly designed circulation system. Each component in the system (i.e. piping, fittings, valves, filters, heaters, etc.) produces a pressure drop (friction loss), which the pump must overcome. The total pressure drop in the system is commonly referred to as total dynamic head (TDH). The larger the TDH, the greater the amount of power required to achieve a given flow rate. Some of the most common methods used to reduce TDH include: 1. Increasing pipe diameter. 2. Reducing pipe length. 3. Reducing the number of sharp bends and turns in the circulation system (piping). 4. Increasing the size of pool return outlets. 5. Increasing the filter size. 6. Increasing the diameter of backwash (or other) valves when present.Remember, not only will the facility reduce its energy consumption to save costs, it will also likely receive sizeable rebates from local utility companies for using energy-saving technology, thus providing a quicker return on investment (ROI). Be sure to consult the local utility company before embarking on the project. |
Eliminating sticker shock
Even with the advantages explained, some facility operators still find the cost of a VSP hard to justify. However, before ruling one out, the price of a new pump should be compared to the expense of doing nothing at all.
For example, an aquatic facility with a 76,000 L (20,000 gal) pool using a single-speed pump may have operational costs of up to $4,700 per year (based on a cost of 20 cents per kilowatt-hour (kWh) and the pump running 24-7). After five years, the facility will have spent $23,500 to operate the pump. Comparable operational costs for a facility with a well-designed circulation system that uses a VSP, however, may be as little as $906 per year. Over the same five-year period, the facility’s costs will be reduced by more than 25 times it would have spent using a single-speed pump. Cost savings will continue to multiply the longer the VSP is used. (Based on the national average. Costs and savings will vary by region).
The initial cost of a VSP can typically be recouped during the second year of operation.
“With the substantial energy-use rebates our local power company offers, in conjunction with the savings in daily operational expenses, our clients are getting back approximately 50 per cent of the pump’s cost in less than a year,” says Caldwell.
Mike Fowler is the commercial marketing and sales manager for Pentair Water Commercial Pool and Aquatics in Sanford, N.C. He has been with Pentair since 1992, starting his career in the technical services department at Purex Pool Products. Fowler has held many managerial roles within the company, including marketing, accounting and products. He can be reached via e-mail at mike.fowler@pentair.com.
