Level 2 (Self)
TECHNOLOGY AREAS
Air Platform
MODERNIZATION PRIORITIES
FutureG
KEYWORDS
CO2 Transcritical compressor, Aviation Refrigeration, Mission Systems Cooling, Scroll Compressor, Semi-Hermetic Reciprocating compressor, Modular Compressor Design, Supercritical Cycle, Aviation Thermal Management, High-Pressure Refrigeration.
OBJECTIVE
The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with section 3.5 of the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws.
The objective of this effort is to design and develop a compact, aviation grade CO2 compressor capable of meeting the unique thermal management demands of military aircraft. The compressor must support high pressure transcritical CO2 cycles while remaining lightweight, compact, and highly efficient over a wide range of heat loads. The project will evaluate potential options such as (but not limited to) scroll, semi hermetic reciprocating, and screw compressor architectures, assessing their respective benefits and challenges, including efficiency, vibration, noise, reliability, turn-down, and high pressure capability, to identify the most suitable design for aviation applications. The selected compressor shall support mission heat loads up to 200 kW with a turndown ratio of 3:1 (threshold) and 4:1 (objective), maintain the TMS outlet temperature at 20 C 5 C under dynamic loads, and reject heat to a 50 C sink during transcritical (R-744) operation using a gas cooler as needed. The compressor shall be lightweight, compact, low-noise, and demonstrate high isentropic efficiency at the design point.
ITAR
The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with section 3.5 of the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws.
DESCRIPTION
This topic focuses on developing a compact, high-efficiency CO2 (R-744) compressor specifically tailored for aircraft thermal management systems (TMS) across a wide range of Air Force platforms, including fighters, transports, tankers, and next-generation autonomous collaborative platforms (ACP). Modern aircraft face growing thermal challenges from advanced mission systems such as radars, electronic warfare, and high-power avionics that demand reliable, lightweight, and efficient cooling solutions. While legacy refrigerants such as R-134a and R-1233zd(E) are commonly used, they require bulky, heavy components that constrain system design. By contrast, CO2 offers high volumetric cooling capacity, environmental neutrality, and the potential for significant reductions in system size and weight. Military aviation operations introduce unique challenges. CO2 systems operate at substantially higher pressures and often in transcritical cycles, requiring compressors capable of safely handling high pressure conditions while minimizing vibration, noise, and weight. The compressor must maintain high efficiency across a wide range of operating conditions, including hot-day ground operations and high-altitude low-temperature environments. This project seeks to develop and demonstrate compressor technologies that deliver a compact, high-efficiency, low-noise, and reliable aviation grade CO2 compressor capable of precise temperature control and reliable operation throughout all mission phases. The proposed work should address the critical challenge of managing high heat loads in military aircraft. This project will leverage the thermodynamic properties of CO2 to develop a compact, lightweight, and energy efficient thermal management CO2 compressor capable of reliable performance during high-demand phases of the mission, such as takeoff, climb and mission system engagement. The compressor should be designed to handle the highly dynamic thermal loads generated by next generation electrified aviation systems, ensuring stable and efficient cooling performance throughout all mission phases. The heat load can vary throughout a mission from notionally 200 kW during takeoff to 75 kW at cruise conditions, and the compressor must be able to operate efficiently over the entire range of heat loads. The compressor must cool the heat load to 20 C 5 C, and be capable of rejecting heat to a heat sink at 50 C with a typical gas-cooler if needed. Proposals should address the development of an aviation-grade CO2 compressor capable of operating efficiently across the full environmental, temperature, and pressure envelopes encountered in aircraft TMS, including high-altitude low-temperature environments, shock, vibration, EMI, etc., while operating in a transcritical thermodynamic cycle.
PHASE I
Design and develop a conceptual laboratory prototype of a compact CO2 compressor optimized for aviation thermal management systems. Perform modeling and simulation to evaluate compressor performance under transcritical operating conditions and validate feasibility of achieving weight and efficiency targets.
PHASE II
Refine and fabricate a functional prototype CO2 compressor based on Phase I results. Conduct laboratory testing to assess heat rejection efficiency, weight reduction, and reliable operation across representative aviation conditions.
PHASE III DUAL USE APPLICATIONS
This phase will transition the developed CO2 compressor for dual application in military and commercial aviation environments, including collaboration with aircraft OEMs to support integration, certification, and flight qualification.
REFERENCES
Kim, Y. M., C. G. Kim, and D. Favrat. "Transcritical or supercritical CO2 cycles using both low-and high-temperature heat sources." Energy 43.1 (2012): 402-415.
