New York State Department of Parks, Recreation & Historic Preservation
Completed: September 2019
Domestic Hot Water and Pool Heating Systems- Replacement Design
Scope of Work:
Investigated and designed reliable, sustainable, and energy-efficient hot water systems across the campus, serving DHW systems, swimming pool water heating, and the hot water for the ice rink Zamboni machines. Also investigated and designed an electrical sub-metering system for select buildings on the campus.
During the feasibility phase, Agarabi Engineering visited Riverbank several times to determine how to measure the DHW peak loads and electrical base loads. The most cost-effective way to measure the DHW loads was to install individual gas meters (with pulse outputs) at each group of boilers, since it would provide high accuracy readings and also allow future measurement of consumption and savings. Electricity was measured by replacing the existing electric meter on each building’s switchgear with a meter that could provide a pulse output.
We then analyzed 5 months of 15-minute interval gas consumption data. We used the peak loads and hour-by-hour consumption patterns to size the new DHW boilers; in every case this resulted in much smaller boilers than existing. On the electrical side, we determined the lowest load for each building to see if a cogeneration or PV system would be a cost-effective option.
During the design phase, we developed a DHW heating strategy that was more efficient than having multiple separate 100% redundant systems. However, budget constraints, existing equipment failure and a lack of qualified staff to operate the proposed equipment combined to undermine this strategy.
The final design, still much more efficient than the existing setup, consisted of replacements with smaller and higher-efficiency units. In low-load areas we replaced multiple 1,000 MBH boilers with point-of-use electric water heaters.