They are air, calcium chloride brine, sodium chloride brine, alcohol, and similar nonfreezing solutions. The purpose of Class 2 refrigerants is to receive a reduction of temperature from Class 1 refrigerants and convey this lower temperature to the area to be air-conditioned.
Elections for the United States Senate will be held on November 8, 2016, with 34 of the 100 seats in the Senate being contested in regular elections whose winners will serve six-year terms from January 3, 2017 until January 3, 2023.
You get to vote for both. But generally not in the same election. Individual senators are up for election every third 2 year cycle of the House of Representatives (thus, every six years). Roughly one third of the senate is up for election every two years. As far as I know, all states stagger their two senate election cycles.