All Case Studies
Project Brief
Puerto Rico
Thermal Energy HQ
Thermal Energy HQ Technical Team
November 20, 2025
Commercial Building
Cooling
Expansion / Capacity Upgrade
Thermal Tank, Heat Pump, DHW Preheat, Cooling Recovery
Project Overview
A laundromat expansion in Puerto Rico was expected to push the site’s existing hot water system beyond its limits. Thermal Energy HQ proposed a simple upgrade centered on a 700-gallon Thermal Tank and a 16 kW-thermal inverter-driven heat pump to build hot water capacity, lower operating cost, and add the side benefit of space cooling in the service area.
The site was adding several high-capacity washers and expected hot water demand to increase by 50 percent. Existing daily usage ranged from 680 to 1,350 gallons per day, averaging 1,085 GPD, and with additional equipment the modeled demand increased to 1,600 GPD. The legacy system relied on three Rinnai tankless water heaters with annual operating cost of $6,610 based on propane at $3.75 per gallon.
TEHQ proposed a 700-gallon Thermal Tank with immersed load-side heat exchanger connected to a 16 kW-thermal R32 variable-speed heat pump. The unit location behind the existing Rinnai equipment simplified installation and reduced piping temperature loss. The heat pump was modeled to provide 120°F+ water to the existing heating plant, leaving the current water heaters in place for redundancy, resilience, and boost capacity to 155°F+.
Because the heat pump discharges cold air, the installation adds free cooling to the service area during operation. The modeling also assumed Luma electricity at $0.28/kWh, with projected additional annual savings of $505 for every $0.05/kWh decrease in electricity cost if paired with planned PV. The case study estimates 9,260 ton-hours of cooling, equivalent to a 5-ton air conditioner operating 7 hours per day at no added cooling cost.
The financial table shows annual DHW cost decreasing from $6,610 to $2,830, producing $3,780 in annual savings, or 57 percent. Total project cost was listed at $21,945 with no available incentives shown, resulting in a 5.8-year payback and a simple ROI of 17.2 percent.
For high-hot-water-use facilities like laundromats, thermal storage plus heat pump preheat can expand capacity, reduce propane consumption, preserve backup equipment, and create useful cooling in the process.
