Residents of a low-income senior apartment building in Santa Rosa have been without air conditioning for more than a month. Many have had to endure triple-digit heat in recent days, with more highs in the 90s this week. The 14-story, 160-unit Bethlehem Tower was built in the 1970s. An internal part of the chiller in the HVAC system broke and the company that manufactures the part is now out of business. Going the route of replacing the chiller altogether would take an estimated four months.