Disclaimer: This blog was first published in 2015. All numbers need to be adjusted to current energy prices and available and utilities government incentives.
The Challenge
Commercial pools are large bodies of water that consume considerable resources. To operate these pools, operators need industrial-size boilers, pumps, chemical systems, lights, filters, control devices, and other electro-mechanical systems. Often, these systems are not interconnected or synchronized, leading to inefficient operations. Overheating or underheating the pool, or accidentally draining thousands of gallons of water due to late detection of mechanical failures in the filter backwash system, are common issues. In the worst cases, operators may expose pool patrons to health hazards due to improper chemical makeup of the water, leading to unsafe swimming conditions. Unexplained high water or energy bills, or catastrophic events leading to pool shutdowns by local health authorities, often trigger the need for expensive pool re-commissioning. Utility bills typically reflect a month's usage and do not provide detailed consumption breakdowns by system or specific dates.
Pool Analysis
In our analysis of numerous pools, we have found that measuring, monitoring, and gathering data on individual systems is essential for reducing waste. By continuously manipulating data from various systems, setting minimum and maximum limits, alerting facility staff when these limits are reached, and automating responses to these scenarios, we can control water and energy consumption to targeted levels. Our solution of choice is the TEK Aquatic Controller by Lincoln Aquatics, a PLC-based control monitoring and reporting system that also functions as an energy performance management solution. The TEK controller gathers data from installed sensors such as flow meters, temperature sensors, pressure sensors, chemistry systems, filtration systems, boilers, and solar systems. These data points are continuously recorded, logged, and instantly reported. The information is displayed on a pool control dashboard, providing a wealth of data processed by the software to generate smart reports. These reports help facility staff quickly correct any anomalies. For example, energy usage graphs over time show metrics of actual consumption and real-time scheduling of subsystems, with automatic actions triggered to prevent catastrophic events when systems deviate from predefined ranges.
Real Pool Case Study
One of our earliest projects involved a 600,000-gallon commercial pool with a surface area of 9,825 sq ft. The ownership was unaware of the exact operating costs, while the CFO suspected a gradual increase over the years.
Our Objectives:
Estimate the pool's annual operating cost as accurately as possible.
Develop a plan to save at least 30% of the annual operating cost.
Ensure any proposed plan has a return on investment (ROI) of less than 5 years.
Our Three Steps Plan:
Step 1: Baseline the Pool Parameters and Operating Costs
We installed a TEK Aquatic Controller to accurately sub-meter the pool boiler for gas usage, the filter loop pump for electrical usage, and makeup water consumption. After a few weeks of data collection, we found the following operating costs:
Gas: 30,000 therms annually at a cost of $1.1625 per therm (adjusted for boiler efficiency), totaling $34,875.
Electricity: A 45 HP pump consumes 301,563 kWh annually at $0.15 per kWh, totaling $45,234.
Water: 750,000 gallons annually for backwashing the pool filters, costing $0.03 per gallon, totaling $22,500. Disposed chemicals cost an additional $5,000, for a total annual cost of $27,500.
Total estimated pool annual operating cost: $107,609.
Step 2: Reduce Waste
Install a VFD on the pool pump, reducing energy consumption by 35%. A 45 HP pump would reduce its consumption by 12 kWh. Total reduced hours annually: 6,750 @ 12 kWh = 81,000 kWh saved, estimated annual savings of $12,150.
Schedule the pool boiler to reduce annual therm usage by 5,000 therms, with estimated annual savings of $5,800.
Step 3: Produce What We Can’t Save or Reduce
Install a 200-collector solar thermal system to produce 22,000 therms per year. The solar system had a $72,000 rebate, with estimated annual gas savings of $25,575.
Install a water recycling plant to save 95% of the water and chemicals wasted, with estimated annual savings of $33,250.
Estimated Total Annual Savings: $76,750 (over 70% of operating costs)
Proposal and Results
The ownership opted for the following parts of our proposal:
Install a solar thermal system: $250,000 with a $72,000 CSI incentive.
Install a VFD on the main pool pump: $15,000 out of pocket.
Schedule the pool boiler: covered under the solar system controls.
Total Out-of-Pocket Cost: $175,000
Annual Savings: $43,500
ROI: 4.02 years
Additional Benefits
Internet-connected and monitored pool system.
Complete pool dashboard for monitoring and diagnostics.
Pool temperature.
Filter loop and solar flow rates.
Solar BTU production.
Boiler BTU spent.
Chemistry usage.
Makeup water consumption.
Data logging of all relevant parameters for future reference.
Alarms via text/email and automated actions.
Remote control.
Filter loop pump schedule.
Load shedding.
Backwash automation.
Summary
By retro-commissioning a pool, owners can benefit from:
Improved system operation and equipment performance.
Enhanced operations and maintenance staff capabilities and expertise.
Increased asset value and energy savings.
Water savings and improved environmental control.
Improved occupant comfort and indoor environmental quality.
Enhanced building documentation.
Reduced operating and maintenance costs.
Improved controls over mechanical systems.
Constant improvement of equipment optimization.
Automated record-keeping.
If you have any questions or suggestions, please don't hesitate to contact Gal Moyal, the CEO of Maktinta Energy, at maktinta@gmail.com
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