Jannis Kounellis, Ambika P3

Last year, visitors to Tate Modern’s Artists’ Rooms could see a room dedicated to Jannis Kounellis. It was filled with some of his most resonant work: a door filled up with drystone walling; burlap sacks of grain, rice, pulses; metal bells. For a founder-member of the Arte Povera movement, it was surprisingly bucolic.

Now, in the bowels of the University of Westminster, past a car park and in what was probably once a series of machine rooms, the other side of Kounellis is on view. As always, he is working with everyday materials, but these are now industrialised – coal, metal, steel, and the city-worker’s historic trademark, the black coat and hat.

These symbols have particular resonance in this space. The show begins in the largest room, its yellowed, dripping walls and concrete floor housing a huge steel structure shaped like a "K" – Kounellis, to be sure, but even more, Kafka, and possibly even Kafka’s Amerika, whose working title was The Man Who Disappeared. Kounellis has always been determined that, through his art, Kafka’s little men do not disappear, do not get overlooked. This large-scale sculpture addesses the industrial nature of the world, topped as it is with tons of coal, covered with mass-produced bottles tightly strapped in with steel guy ropes, covered with heavy black cloth. The sculpture looms above the visitors dodging in and out of the blind alleys of the "K", passing "windows" of glass bottles that cannot be seen through, searching for a centre that does not exist. Only from above, from both ends of the gallery, can the overall shape be determined and its meaning deduced: distance brings clarity.

This is a world where constraints are constant, where views are occluded, where industry towers over everything. Through an archway, hats and coats line the walls of an alcove (pictured below; photo Manolis Baboussis), some on industrial rails, some pierced through and hung from butcher’s hooks. More bottled panels above promise a vista on to something, while more dense black fabric prevents it; a sewing machine dangles (main picture; photo Michael Maziere), stressing the manufactured nature of what we cover ourselves in.

More little-man travels can be seen in another piece, a large black bundle, tied and lurking in a corner: the characteristic makeshift pack of the immigrant, the pedlar. At a distance, it’s a great brooding black void, sucking in light. Another coat and hat are placed more demurely on a coat-rack, which then crazily hangs in the air, suspended by yet more steel ropes; across the room, a woman’s silk nightgown similarly hangs, the two fetishised, "empty" bodies kept apart, always within sight, always untouchable.

Kounellis has been working with a limited number of materials and themes for most of his artistic life, but this in no way indicates a poverty of imagination. Instead he is a composer, creating theme and variation, weaving rhythm, regularity and repetition together and then separating them out, making us look, in his humane exploration of identity and cosmic inevitability, not only at the objects of our existence but at our existence itself.

He always returns, however, to his black-coated worker, to the little man, Chaplin’s tramp, who picks himself up, making what he can of his world and walking on, without false hope, but also without resentment, without delusion. For such dark, spare art, the mood is always surprisingly, not optimistic, but benign. This is the world. It is what it is. But we can also become greater than the sum of our parts. We are Kafka’s Josef K. But Josef K was, as all little men are, a great man. Kounellis lets us be that too.

• Jannis Kounellis, presented by Sprovieri Gallery, is at Ambika P3, University of Westminster until 30 May