Hval is an alternate name for Ytre Ådal parish ("sokn"), which was within Ådal clerical district ("prestegjeld"). So one way to refer to this place would be Ytre Ådal, Ådal prestegjeld, Buskerud, Norway. Back in 1853 (when Norway was ruled by the Swedish king) this would have been spelled Yttre Aadal, Aadalen prestegjeld, Buskerud, Norway.
On the URL in your reference for the baptismal record, please also note that Norwegian researchers prefer that you use the "brukslenke" (i.e., https://www.digitalarkivet.no/kb20061102350312) rather than the "permanent bildelenke" (i.e., http://urn.digitalarkivet.no/URN:NBN:no-a1450-kb20061102350312.jpg). This is because the first gives you a link to the full parish book, at the right page, so you can page back and forth to see the context of the reference, while the second is a link to a static jpg.