The Building Authority shall keep account of the gross total income derived from each separate project or any combination thereof undertaken pursuant to this chapter. Disbursements from a given account in the public building fund shall be ordered by the authority only for the payment of:
(1) The cost of maintenance and operation of the facility or facilities, unless otherwise provided for;
(2) The principal of and interest on the bonds issued for each project, or combination thereof; and
(3) Any other purposes set forth in the resolution authorizing the issuance of said bonds.