Federal Capital Revolving Fund Act of 2021 This bill establishes the Federal Capital Revolving Fund to support the acquisition of facilities for federal agencies. Specifically, the fund supports facility acquisition projects that cost $250 million or more, including purchase, construction, and lease-purchase options. Agencies must submit requests for funds to specified congressional committees and the General Services Administration, as appropriate; the receipt of funds is also contingent on specific legislative approval and appropriations for repayments. Agencies must make repayments to the fund at least annually for an agreed-upon term, but for no longer than 15 years.