Improved Environmental Control Units (IECU) Prototype Project


The final RFS for IECU has been released by the Government. There are no changes to the attachments previously provided. Please find the final RFS below:

IECU Final RFS – 1.21.22

This opportunity is now accepting solution submissions in addition to questions related to IECU. Please note the following due dates:

Questions due: January 27th, 2022

Solutions due: February 21st, 2022



The draft RFS for IECU is now available to the public. The Government will provide a deadline for both questions and solutions with the final RFS release.

In addition, questions are now being accepted for this opportunity. All questions related to this RFS shall be submitted utilizing the Vendor Questions Form provided in Attachment 3. Questions must be submitted via email to [email protected], with “IECU Prototype Vendor Questions” in the subject line.

Please find below the draft RFS for IECU and Attachments 1 – 9:

IECU Draft RFS – 1.19.22

Attachment 1: PD 4120-1401 ACs Horz Vert Compact 2014.01.01

Attachment 2: Rfrnc List RTK W51362-5180-95-N18-5180-00-596-1474 Sep 2018

Attachment 3: Question Form

Attachment 4: Data Rights Assertions Tables

Attachment 5: Data Rights License Terms Definitions

Attachment 6: Terms and Conditions and EULA

Attachment 7: Security Process for Vetting Vendors

Attachment 8: Vendor Self Vetting Form

Attachment 9: Telecommunications Representation

Improved Environmental Control Units (IECUs) are portable modular units that heat and cool shelters housing Soldiers and sensitive electronics. There are seven variants in the IECU family which include 9K, 18K-1, 18K-3, 36K, 36K-R, 60K, and 60K-CBRN. This prototype involves only the 9K, 18K-1, 18K-3 and the 36K, however changes to the 36K may propagate to the 36K-R.

The overarching IECU program is underway, with systems in production. The U.S. Army, Product Manager – Force Sustainment Systems (PM-FSS) is now looking toward future needs, initiating an R&D project that seeks to develop and apply technologies introducing new necessary capabilities.

Notably, with the world’s transition to refrigerants that have lower global warming potential (GWP), future IECUs must be able to use other refrigerants so they can be maintained more effectively and more nimbly upgraded to allow for flexibility in locations with strict regulations. An additional benefit foreseen with the technologies needed to achieve this goal, is decreased energy consumption and power draw, which results in logistical savings and reduced emission of carbon-dioxide.

This prototype effort will provide design, development, and verification of several prototypes demonstrating technologies that would be introduced into the overall IECU family. The effort will take a phased approach allowing the Government to continue to deploy these systems throughout the world with the ultimate goal being to design, develop, and verify cooling equipment that adheres to the international refrigerant regulations. The project will consist of multiple phases for development of several technologies for insertion into the Government-owned IECU Technical Data Package (TDP). The research and development of technologies, along with the fabrication of the prototypes that demonstrate those technologies, will be followed by developmental and operational testing. Upon validation and successful prototype completion, the solution design will be transitioned into the IECU TDPs to incorporate the update into future production systems.

The prototypes produced within this project are envisioned to demonstrate the following enhancements:

  • ability to use a low-GWP refrigerant in the 9K, 18K-1, 18K-3 and 36K IECUs;
  • ability to use multiple low-GWP refrigerants, flexibly, making field retrofits possible without the need for equipment change;
  • increased cooling capacity for the 9K IECU;
  • decreased water carryover from the 9K;
  • improved reliability; and
  • the side benefits of decreased surge current draw and decreased overall power draw and energy consumption.

The IECU R&D project is intended to begin with an analysis of alternatives (AoA) and conceptualization followed by design activities and fabrication of alpha prototypes. Upon completion of the alpha prototypes, small-scale test and evaluation events will be conducted to validate the major technical and operational components and capabilities leading to fabrication of full-scale operational prototypes used during formal testing to validate initial operational capability (IOC).

In addition, while modifications are being made to achieve the core goals, some design changes may also improve the overall performance of all the variants with regard to reliability, decreased surge of current draw, and decreased overall power and energy consumption, and provide feedback about parts obsolescence.

IECU R&D Period of Performance is anticipated to be 60 months (5 years). This will be an unclassified prototype project.