AReCoS

Product brief

AReCoS dual-fuel rooftop heat pump

Up to 10 tons · heat pump heating with a gas heat section · the controller picks the cheaper heat. The same rooftop unit as the all-electric configuration.

  • 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

Rooftop unit · the dual-fuel configuration

Why a heat pump, if the gas stays?

It is designed to heat whenever that costs less than gas, and it cools in summer. Gas takes the peaks and the coldest nights.

Why AReCoS, in three reasons

  1. No defrost stopsA new electromechanical way to remove frost: a patent-pending air–water heat exchanger, designed to keep frost thin and clear it while heating, without running backwards as an air conditioner (how).
  2. One controllerU.S. Patent 12,768,557. Designed to:
    • pick the cheaper heat, heat pump or gas, every hour, or the lower-carbon one if the owner prefers
    • run the whole unit on the least electricity
    • work with no cloud in the control path
    • answer the grid, and flag faults and leaks early
  3. Ground-readyA ground loop or neighborhood thermal network is designed to connect to the same unit. Sized for the whole winter, the loop needs no gas; letting gas carry the coldest hours shortens it. The gas section, or electric backup, stays as a safety backup (how).

Rooftop: all-electric and dual-fuel in prototype development; pilots of both targeted for 2027; commercial units targeted for 2028.

The cheaper heat, hour by hour, in about a minute: an illustrated explainer with captions, on an illustrative day; not test footage.

A fixed-switchover dual-fuel unit

  • Switches at one outdoor temperature
  • Fuel prices entered once, if at all
  • Often blind to time-of-use rates and demand charges
  • Uses a rating-sheet curve, not the machine
  • Each unit decides alone

A dual-fuel AReCoS unit

  • Switchover designed to follow the price of heat
  • Designed to read live or time-of-use prices
  • Demand charge designed into the same decision
  • Designed to know its own efficiency, right now
  • Units designed to share the switchover
One cold weekday on a time-of-use rate, hour by hour A time-of-use electricity price, low overnight, high in a morning and an evening peak and moderate at midday. Below it, two units heat the same building through the day. A dual-fuel unit with a fixed switchover goes to gas at one outdoor temperature, so it burns gas through the cheap night hours and runs the heat pump into the evening peak. The AReCoS controller is designed to weigh, every hour, what heat costs from the heat pump and from gas, and run the cheaper: the heat pump through the cheap hours, pre-heating before the morning peak, and gas through the two peaks. A panel shows the two costs at the hour the playhead has reached. HEAT PUMP GAS PEAK PEAK PRICE FIXED SWITCHOVER: ONE OUTDOOR TEMPERATURE AReCoS: THE CHEAPER HEAT, HOUR BY HOUR 12 AM PRE-HEAT NOON 6 PM 12 AM AReCoS CONTROLLER: COST OF HEAT AT 6 PM HEAT PUMP STANDBY GAS RUNS
Illustrative, not a measured result: one cold weekday on a time-of-use rate. A fixed switchover burns gas through the cheapest electricity of the day and runs the heat pump into the evening peak. The AReCoS controller is designed to weigh the cost of heat from each source every hour, and run the cheaper one.

  • Knows its own efficiency

    Designed to work out the heat pump’s efficiency from its own model of the machine, at this hour’s outdoor temperature, load and frost state.

  • Plans the day

    Designed to pre-heat on cheap power before a peak, coast through it, and give gas only the hours where gas heat costs less.

  • Holds the building’s peak

    Across a roof, designed to keep some units on the heat pump and move others to gas, to hold the building’s kW cap.

  • Shows its reasons

    Every switch designed to be logged with its reason and the prices behind it, over BACnet.

How it choosesAll-electric or dual-fuel

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