A pyroelectric system (10) is disclosed that includes a plurality of pyroelectric modules (44, 46, 48, 50). The pyroelectric modules individually include a pyroelectric element, a first port (44a, 46a, 48a, 50a), a second port (44b, 46b, 48b, 50b), and an internal module fluid flow path (26) between the first port and the second port in thermal communication with the pyroelectric element. The pyroelectric modules are arranged along a cascade fluid flow path (51) connecting the first ports of the pyroelectric modules. A hot side inlet (28) to the cascade fluid flow path receives fluid at a first temperature from a heat source in fluid communication with the cascade fluid flow path, and the fluid is discharged from the cascade fluid flow path to a hot side outlet (34). A sink fluid flow path (53) comprises fluid at a second temperature lower than the first temperature, and is in fluid communication with the second ports of each of the plurality of pyroelectric modules.