A reciprocating compressor comprising: a housing having an inner surface defining at least one compression chamber, the housing having a first aperture and a second aperture; a first piston having at least one compression face, the piston being slidably disposed within the compression chamber; a first piston rod having proximate portion and a distal portion, the proximate portion being slidably received within the first aperture, the first piston rod being drivably connected to the first piston; a second piston having at least one compression face opposed to the first piston compression face, the second piston being slidably disposed within the compression chamber; a second piston rod having proximate portion and a distal portion, the proximate portion being slidably received within the second aperture, the second piston rod being drivably connected to the second piston; a first actuator attached to distal portion of the first piston rod; and a second actuator attached to the distal portion of the second piston rod; wherein the first and second piston rod define a translation axis extending through the compression chamber, wherein the first and second actuators (24, 64) are configured to drivably reciprocate the first and second pistons (42, 44) within the compression chamber along the translation axis; wherein at least one actuator (24, 64) comprises a force generator and a force accumulator; and characterised in that the accumulator comprises a capacitor having a first conductive material attached to one of the first and second piston rods (12, 14) and a second conductive material fixed with respect to one of the first and second piston rods (12, 14), whereby said at least one capacitor has moving plates and has a variable capacitance. a housing having an inner surface defining at least one compression chamber, the housing having a first aperture and a second aperture; a first piston having at least one compression face, the piston being slidably disposed within the compression chamber; a first piston rod having proximate portion and a distal portion, the proximate portion being slidably received within the first aperture, the first piston rod being drivably connected to the first piston; a second piston having at least one compression face opposed to the first piston compression face, the second piston being slidably disposed within the compression chamber; a second piston rod having proximate portion and a distal portion, the proximate portion being slidably received within the second aperture, the second piston rod being drivably connected to the second piston; a first actuator attached to distal portion of the first piston rod; and a second actuator attached to the distal portion of the second piston rod; wherein the first and second piston rod define a translation axis extending through the compression chamber, wherein the first and second actuators (24, 64) are configured to drivably reciprocate the first and second pistons (42, 44) within the compression chamber along the translation axis; wherein at least one actuator (24, 64) comprises a force generator and a force accumulator; and characterised in that the accumulator comprises a capacitor having a first conductive material attached to one of the first and second piston rods (12, 14) and a second conductive material fixed with respect to one of the first and second piston rods (12, 14), whereby said at least one capacitor has moving plates and has a variable capacitance.