American OEM Echogen Power Systems said it is developing a high-temperature CO2 (R744) heat pump capable of reaching a maximum outlet temperature of 400°C (752°F) with a COP of between 1.4 and 2.

“We have completed laboratory-scale system testing of a 50kW [14.2TR] steam-generating unit and are developing a 500kW [142.1TR]pilot for process gas heating and a 10MW [2,843.5TR] demonstration system for steam generation,” said Echogen CTO Timothy Held. “A three-year development cycle will start in mid-2024 for the pilot and demonstration systems. Our goal is the commercial launch of a fully operational 5MW system by the end of 2027.”

Held shared the development progress of Echogen’s supercritical CO2 (sCO2) heat pumps at the ATMOsphere (ATMO) Europe Summit 2023 held last September in Brussels and organized by ATMOsphere, publisher of R744.com.

“Our heat pumps feature high-temperature heat generation capabilities, utilizing the thermally stable, high-vapor pressure refrigerant CO2, oil-free industrial gas [steam] compression and low-temperature heat sources,” said Held.

Held noted that Echogen is currently pursuing funding from government entities for the heat pumps, including from the Department of Energy Advanced Manufacturing Office (DOE AMO) and Advanced Research Projects Agency-Energy (ARPA-E). The Akron, Ohio-based company specializes in developing scalable heat-to-power systems designed to efficiently capture and convert heat energy into usable power or upgraded heat.

Focusing on high heat

Held said Echogen’s original involvement with CO2 power cycles focused on industrial waste heat recovery. The company recently began developing high-temperature heat pumps and set its sights on a temperature range of 150°C (302°F) to 400°C for process heating applications. Currently, heat pumps can only produce steam at these temperatures using a steam compressor.

“Above 200°C [392°F], we target applications essential for industries like petrochemical, paper and pulp, food processing and even district heating with steam,” said Held.

“Current alternatives to fossil fuel-fired boilers, such as direct electric heating, incur high operating costs due to the low achievable COP,” he added. “Existing heat pumps [regardless of refrigerant] are limited to lower temperatures of around 130°C [266°F], with some projects under development aiming for 165°C [329°F].”

Held underscored the efficiency of Echogen’s system, which he said can operate at a high COP without waste heat and can achieve steam pressure of more than 20bar (290psi).

Italian manufacturer Turboden has developed large heat pumps that use isobutane (R600a) and isopentane (R601a) in combination with a mechanical steam compressor to reach high temperatures suitable for the energy-intensive pulp and paper industry.

Green steam and heat

The concept of “green steam” was a focal point of Held’s presentation. Steam is used in many industrial applications to provide power and heat. Rather than replace steam outright, Echogen is focused on preserving existing industrial infrastructure and replacing the fossil fuel-powered boilers used to generate steam instead.

“Conventional heat pumps generate low-pressure steam [below 2bar (29psi)], but Echogen’s system can produce medium-pressure [2–20bar (29–290psi)] steam from ambient sources with a COP of 1.4 to 2,” said Held. “This makes it a viable and cost-effective alternative to traditional steam boilers.”

Held said Echogen’s system is adept at heating single-phase process fluids used in drying, water heating, oil and chemical processing.

“What sets our technology apart is its ability to heat these fluids up to 350°C [662°F]; we have plans to exceed this limit while operating with an exceptional COP,” said Held.

Held also elaborated on the economic and environmental advantages of Echogen’s system. “When we compare our technology to natural gas, especially when incorporating a $60 [€55.50]/ton carbon tax and a 30% tax credit available in the U.S. based on the Inflation Reduction Act [IRA], the cost-effectiveness becomes even more apparent,” said Held. Our heat pump offers a competitive alternative to fossil fired and direct electric heating with the added advantage of being able to supply chilled water at no additional costs,” he continued. “The high efficiency of the heat pump leads to shorter payback periods due to reduced operating costs associated with its use.”

“Above 200°C [392°F], we target applications essential for industries like petrochemical, paper and pulp, food processing and even district heating with steam.”

Timothy Held, CTO of Echogen Power System

Author Saroj Thapa