In an age where climate change, rising utility costs, and decarbonization are reshaping how we design and operate buildings, the HVAC industry stands at the forefront of innovation. One of the most promising developments in sustainable building energy solutions is Wastewater Energy Transfer (WET)—a technology that transforms a wasted byproduct into a powerful resource.
The Untapped Potential Going Down the Drain
Every day, the average person uses approximately 60 gallons of waste water. This water eventually exits the building through drains, carrying significant thermal energy into the sewer.
WET systems recover thermal energy from greywater and blackwater sources within buildings, sanitary sewers, and treatment facilities, redirecting it to heat domestic water and to support HVAC operations. This technology represents a key advancement in the development of sustainable infrastructure.
Two Powerful Solutions: PIRANHA and SHARC
HTS, in partnership with SHARC Energy, offers two leading wastewater energy solutions designed to meet varying building sizes and system requirements: the PIRANHA and SHARC systems.
PIRANHA: Self-Contained and Scalable
The PIRANHA is a self-contained water-to-water heat pump system that extracts heat from a building's wastewater to heat potable domestic hot water (DHW).
Engineered for use in a variety of applications—including student residences, apartments, hotels, and regional hospitals—the PIRANHA system provides:
The PIRANHA HC model further enhances versatility by simultaneously providing space cooling and DHW production, achieving even higher combined COPs.
SHARC: Industrial-Grade Energy Transfer
For larger buildings and district energy applications, the SHARC system offers industrial-scale energy transfer. SHARC systems incorporate macerators, high volume filtration, wide gap heat exchangers and automated back-flushing valves enabling high-capacity energy exchange:
SHARC is ideal for hospitals, district energy systems, manufacturing plants, and data centers where wastewater volumes are large and consistent.
Applications Across Sectors
Wastewater energy transfer is uniquely versatile and applicable across a range of sectors:
Whether retrofitting existing buildings or integrating into new developments, WET solutions provide energy savings, emissions reductions, and most importantly: return on investment.
How It Works:
Both PIRANHA and SHARC systems function on a simple principle: recovering thermal energy from wastewater leaving the building and reuse it where needed.
In PIRANHA systems, wastewater enters a holding tank, where a specially designed evaporator extracts heat before the water is discarded. This low grade thermal energy is transferred via a direct domestic condenser to incoming cold water, producing hot water.
The SHARC system adds a macerator and filter system, allowing for use in higher-flow environments. After filtration, the wastewater passes through an industrial plate-and-frame heat exchanger, where the thermal energy is made available to the building or district system.
Geothermal Synergy: Enhancing Efficiency
One innovative application of WET systems is their compatibility with geothermal applications. By pairing PIRANHA or SHARC systems with geothermal fields experiencing an annual load imbalance, buildings can reduce the number of boreholes required. This can yield large capital expenditure (CapEx) savings.The energy transferred from the waste water also provides operational expenditure (OpEx) savings as the energy doesn’t need to be sourced elsewhere.
Proven Success: Real-World Installations
WET systems have already been implemented in several high-impact projects across North America, demonstrating both environmental and economic benefits.
Controls and Maintenance
All SHARC Energy systems include advanced controls with a user-friendly touchscreen interface, remote monitoring, and Building Automation System (BAS) integration via BACnet or Modbus. Alerts, performance tracking, and data trending help building operators optimize energy use in real-time.
Maintenance requirements are low and designed to fit into existing operations. PIRANHA systems require biannual check-ups, while SHARC systems involve quarterly inspections—particularly during the first two years of operation.
A Strategic Step Toward Sustainability
As governments, developers, and building owners aim for net-zero targets, WET offers a practical and scalable solution. It not only offsets traditional heating and cooling loads but also reduces the dependence on fossil fuels, reduces emissions, and improves energy efficiency.
The benefits are clear:
Conclusion: Don’t Let Heat Go Down the Drain
Wastewater is no longer just a byproduct of modern living—it’s an opportunity. With technologies like PIRANHA and SHARC, HTS is helping redefine energy efficiency and sustainability in the built environment.
Whether you’re planning a multi-unit residential development, retrofitting a hospital, or designing a district energy system, WET can play a pivotal role in achieving your energy and climate goals.
It’s time to stop letting heat go to waste. Harness the power of wastewater energy and turn your building into a high-performance, eco-conscious system built for the future.