The authority may at any time and from time to time issue refunding bonds for the purpose of refunding the principal of and the interest on any bonds of the authority issued under this chapter and then outstanding. The refunding bonds may be issued regardless if the principal and interest have matured at the time of the refunding. The refunding bonds may be issued for the payment of any expenses incurred in connection with the refunding and any premium necessary to be paid in order to redeem, retire, or purchase for retirement the bonds to be refunded. The proceeds derived from the sale of any refunding bonds shall be used only for the purposes for which the refunding bonds were issued. Any refunding may be effected either by sale of the refunding bonds and the application of the proceeds, or by exchange of the refunding bonds for the bonds or interest coupons to be refunded. The holders of any bonds or coupons to be refunded shall not be compelled to surrender their bonds or coupons for payment or exchange prior to the date on which they may be paid or redeemed by call of the authority under their respective provisions. All provisions of this chapter pertaining to bonds of the authority that are not inconsistent with this section shall, to the extent applicable, also apply to refunding bonds issued by the authority. The authority may issue bonds for the purpose of refunding the principal of and the interest on any of its bonds and for any other purpose for which it is authorized to issue bonds. The provisions of this chapter respecting refunding bonds shall apply only to the portion of the combined issue authorized for refunding purposes and the provisions respecting other financing shall apply to the remaining portion of the combined issue.