EXHIBIT 31(b)
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                                  CERTIFICATION
   pursuant to Rules 13a-15 and 15d-15 of the Securities Exchange Act of 1934

I, Robert I. Lieberman, Chief Financial Officer of Thermodynetics, Inc., certify
that:

1. I have reviewed this quarterly report on Form 10-QSB of Thermodynetics, Inc.;

2. Based on my knowledge, this report does not contain any untrue statement of a
material fact or omit to state a material fact necessary to make the statements
made, in light of the circumstances under which such statements were made, not
misleading with respect to the period covered by this report;

3. Based on my knowledge, the financial statements, and other financial
information included in this report, fairly present in all material respects the
financial condition, results of operations and cash flows of the small business
issuer as of, and for, the periods presented in this report;

4. The small business issuer's other certifying officers and I are responsible
for establishing and maintaining disclosure controls and procedures (as defined
in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over
financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f))
for the small business issuer and have:

        a) designed such disclosure controls and procedures to provide that
        material information relating to the small business issuer, including
        its consolidated subsidiaries, is made known to us by others within
        those entities, particularly during the period in which this report is
        being prepared;

        b) designed such internal control over financial reporting, or caused
        such internal control over financial reporting to be designed under our
        supervision, to provide reasonable assurance regarding the reliability
        of financial reporting and the preparation of financial statements for
        external purposes in accordance with generally accepted accounting
        principles;

        c) evaluated the overall effectiveness of the small business issuer's
        disclosure controls and procedures to provide that material information
        relating to the registrant, as of the end of the period covered by this
        report based on such evaluation; and

        d) disclosed in this report any change in the small business issuer's
        internal control over financial reporting that occurred during the small
        business issuer's most recent fiscal quarter (the small business
        issuer's fourth fiscal quarter in the case of an annual report) that has
        materially affected, or is reasonably likely to materially affect, the
        small business issuer's internal control over financial reporting; and

5. The small business issuer's other certifying officers and I have disclosed,
based on our knowledge and our most recent evaluation of internal control over
financial reporting, to the small business issuer's auditors and the audit
committee of the small business issuer's Board of Directors:

        a) all significant deficiencies and material weaknesses in the design or
        operation of internal control over financial reporting which are
        reasonably likely to adversely affect the small business issuer's
        ability to record, process, summarize and report financial information;
        and

        b) any fraud, whether or not material, that involves management or other
        employees who have a significant role in the small business issuer's
        internal controls over financial reporting.


         Date: August 11, 2004      By:     /s/  Robert I. Lieberman
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                                           Robert I. Lieberman
                                           Treasurer and Chief Financial Officer