AReCoS

Product brief

AReCoS rooftop heat pump

Light commercial · up to 10 tons · all-electric or dual-fuel · ground-ready. Air source, with the AReCoS air–water heat exchanger and controller inside.

  • Controller: U.S. Patent 12,768,557, under test in a research agreement (CRADA) with UT-Battelle, LLC, which manages Oak Ridge National Laboratory for the U.S. Department of Energy
  • Air–water heat exchanger: patent pending
  • Patent and CRADA record
Reserve a place in the first unitsDownload the rooftop heat pump brief PDF

The unit

Two configurations, one rooftop unit.

AReCoS is developing rooftop heat pumps up to 10 tons in two configurations:

  • All-electric: Heat pump heating with optional electric resistance backup.
  • Dual-fuel: Heat pump heating combined with a gas heat section, with fuel switching managed by the embedded AReCoS controller (how it switches).

Both configurations are in prototype development. Performance targets and specifications will be validated through testing and certification.

Prototype development
All-electric and dual-fuel configurations.
Initial rooftop pilots
All-electric and dual-fuel, targeted for 2027.
Commercial units
Targeted for 2028.

Prototype design, to be updated during certification

  • 22.1IEER
  • 13.4EER
  • 3.72COP at 47 °F
  • 2.57COP at 17 °F

10-ton unit.

Design basis

  • All seasonsDesigned to hold 100% of its 47 °F rated heating capacity at 0 °F and at least 70% at −15 °F, each 5 °F colder than the cold-climate test points used for commercial rooftop units, and to keep cooling up to 115 °F. The building’s load and sizing set how much backup it needs.
  • ConfigurationsAll-electric with optional electric backup, or dual-fuel with a gas heat section.
  • Ground-readyDesigned to join a ground loop or thermal network later. Sized for the whole winter, a loop needs no gas; letting gas carry the coldest hours shortens the loop. Gas or electric backup stays for safety.
  • Grid responseDesign targets: hold a kW cap, shed 15% on request or 40% in a critical event, or add 15%, within comfort limits and the load the unit is carrying. The grid can ask; the controller decides how.
  • DiagnosticsDesigned to track refrigerant charge in every mode and name the likely cause of a fault.
  • StandardsR-454B (A2L). Designed for UL 60335-2-40 listing, AHRI 340/360 ratings and ASHRAE 90.1.

Inside the unit

Winter, heating: the pumped water–antifreeze loop in the air–water heat exchanger is active around the outdoor coil, which is the evaporator; hot refrigerant goes to the indoor coil. Winter: heating WATER–ANTIFREEZE LOOP ACTIVE OUTDOOR AIR AIR–WATER HEAT EXCHANGER Outdoor coil (evaporator) WATER PUMP ON T AMBIENT Compressor Indoor coil (condenser) EXV P, T P, T WARM AIR TO THE BUILDING Winter, heating: the pumped water–antifreeze loop in the air–water heat exchanger is active around the outdoor coil, which is the evaporator; hot refrigerant goes to the indoor coil.Outdoor air passes the air–water heat exchanger, where the water pump drives the water–antifreeze loop around the outdoor coil. Cold refrigerant goes from the outdoor coil to the compressor, and hot refrigerant from the compressor to the indoor coil, which warms the air to the building; it returns through the EXV to the outdoor coil. Sensors read the outdoor air temperature, and the refrigerant pressure and temperature entering the compressor and leaving the indoor coil. Winter: heating WATER–ANTIFREEZE LOOP ACTIVE OUTDOOR AIR AIR–WATER HEAT EXCHANGER Outdoor coil (evaporator) WATER PUMP ON T AMBIENT Compressor Indoor coil (condenser) EXV P, T P, T WARM AIR TO THE BUILDING Summer, cooling: hot refrigerant goes to the outdoor coil, which is the condenser, and rejects its heat through the water–antifreeze loop to the outdoor air; cold refrigerant goes to the indoor coil. Summer: cooling WATER–ANTIFREEZE LOOP ACTIVE OUTDOOR AIR AIR–WATER HEAT EXCHANGER Outdoor coil (condenser) WATER PUMP ON T AMBIENT Compressor Indoor coil (evaporator) EXV P, T P, T COOL AIR TO THE BUILDING Summer, cooling: hot refrigerant goes to the outdoor coil, which is the condenser, and rejects its heat through the water–antifreeze loop to the outdoor air; cold refrigerant goes to the indoor coil.Outdoor air passes the air–water heat exchanger, where the water pump drives the water–antifreeze loop around the outdoor coil. Hot refrigerant goes from the compressor to the outdoor coil, and through the EXV to the indoor coil, which cools the air to the building; cold refrigerant returns from the indoor coil to the compressor. Sensors read the outdoor air temperature, and the refrigerant pressure and temperature leaving the compressor and entering the indoor coil. Summer: cooling WATER–ANTIFREEZE LOOP ACTIVE OUTDOOR AIR AIR–WATER HEAT EXCHANGER Outdoor coil (condenser) WATER PUMP ON T AMBIENT Compressor Indoor coil (evaporator) EXV P, T P, T COOL AIR TO THE BUILDING
  • Hot refrigerant
  • Cold refrigerant
  • Water–antifreeze loop
  • Sensor
  • AReCoS embedded controller designed to set compressor · reversing valve · EXV · fan · blower · water pump together

In every season, heat moves between the outdoor air and the refrigerant through the water–antifreeze loop: air to loop to refrigerant when heating, the reverse when cooling.

Impact

What one unit is designed to save.

Estimates for a 10-ton rooftop unit heating and cooling a Minneapolis building, against a heat pump unit built to the federal minimum efficiency; not measured results.

  • 5,000–8,000 kWha year.
  • $650–1,050a year.
  • 2–3 t CO2ea year.

Times a thousand, as arithmetic rather than a forecast: about 5 to 8 million kWh, $0.65 to 1.05 million and 2,000 to 3,000 tonnes CO2e a year.

How it is estimated: 3,000 to 5,000 kWh a year from higher efficiency and no defrost cycles, plus 2,000 to 3,000 kWh of backup resistance heat the unit is designed not to need, at about 13¢ per kWh, the 2025 U.S. commercial average. Hours, load, climate and tariff move these numbers for any one building. The full method.

Let's talk.

Pilot sites for the AReCoS heat pump RTU, manufacturing partners for the first builds, the controller for your refrigeration system, or the EV heat pump for your vehicle program.

Email info@arecos.net
625 Kenmoor Ave SE, Suite 350
Grand Rapids, Michigan 49546