Is it possible for exergy to be negative For exergy change to be negative For exergy destruction to be negative?

Exergy itself cannot be negative, as it represents the maximum useful work obtainable from a system relative to a reference environment. However, exergy change can be negative, indicating that the system has lost useful work potential, typically due to irreversibilities or energy dissipation. Similarly, exergy destruction, which quantifies the loss of useful work potential due to irreversible processes, is always non-negative, reflecting the second law of thermodynamics. Thus, while exergy values themselves remain non-negative, changes in exergy and exergy destruction can indicate losses in useful energy.