Company keeps cool and is bought

For $455 million, Emcor Group Inc. is acquiring Ohmstede Ltd., which helps refineries and petrochemical companies cool fluids passing through their conduits.

Ohmstede has been owned for more than a year by First Reserve Corp., a private equity fund with offices in Greenwich and Houston that invests in energy-sector companies.

Based in Norwalk, Emcor provides a range of maintenance services for facility electrical and mechanical systems.

Founded in 1905 in Beaumont, Texas, as a machinery repair shop, for the past 60 years Ohmstede has focused on the manufacture and maintenance of heat exchangers used to draw excess heat from fluids passing through piping.

At last report, Ohmstede had more than 500 employees.