Learn Spanish (Spain): Hay que limpiar el frigorífico.

Both express obligation, but hay que is impersonal. It means "one must" or "it is necessary to" do something in general, without specifying exactly who has to do the chore. If you specifically wanted to say "we have to clean the fridge," you would use the personal form tenemos que instead.

Why is "limpiar" left in its dictionary form instead of being conjugated?

After the phrase hay que, the verb that follows must always be an infinitive (the base form ending in -ar, -er, or -ir). Because hay que doesn't point to a specific person (like I, you, or we), we don't conjugate the action verb.

Is the "hay" in this sentence the same word that means "there is" or "there are"?

Yes! On its own, hay means "there is" or "there are." However, when you add que directly after it to form hay que, it becomes a fixed phrase with a completely new meaning: "it is necessary to" or "one must."

I usually hear "nevera" for fridge. Can I use that instead of "frigorífico"?

Absolutely. In Spain, both frigorífico and nevera are perfectly natural and interchangeable words for "fridge." Frigorífico is slightly more formal but still extremely common in everyday spoken Spanish.