An apparatus to control a temperature within a housing, the apparatus comprising: a housing to contain a field device of a process control system, wherein the housing includes a relatively warmer fluid aperture and a relatively cooler fluid aperture; wherein the relatively warmer fluid aperture is different and separate from the relatively cooler fluid aperture, and both allow a direct access to the internal compartment of the field device; a vortex tube that is external to the housing and that includes a first outlet , a second outlet , a first passageway fluidly coupling the first outlet to the relatively cooler fluid aperture of the housing , and a second passageway fluidly coupling the second outlet to the relatively warmer fluid aperture of the housing , wherein the vortex tube is configured to divert a first portion of a fluid to the first outlet and divert a second portion of the fluid to the second outlet ; a first flow control member having a first cool fluid outlet and a second cool fluid outlet, wherein the first cool fluid outlet directs cool fluid to an atmosphere surrounding the housing , and wherein the second cool fluid outlet directs cool fluid to the first passageway to fluidly couple the first outlet to the housing to supply at least a portion of the first portion of the fluid directly to an internal cavity of the housing ; and a second flow control member having a first warm fluid outlet and a second warm fluid outlet, wherein the first warm fluid outlet directs warm fluid to an atmosphere surrounding the housing , and wherein the second warm fluid outlet directs warm fluid to the second passageway to fluidly couple the second outlet to the housing to supply at least a portion of the second portion of the fluid directly to the internal cavity of the housing separately from the first portion. a housing to contain a field device of a process control system, wherein the housing includes a relatively warmer fluid aperture and a relatively cooler fluid aperture; wherein the relatively warmer fluid aperture is different and separate from the relatively cooler fluid aperture, and both allow a direct access to the internal compartment of the field device; a vortex tube that is external to the housing and that includes a first outlet , a second outlet , a first passageway fluidly coupling the first outlet to the relatively cooler fluid aperture of the housing , and a second passageway fluidly coupling the second outlet to the relatively warmer fluid aperture of the housing , wherein the vortex tube is configured to divert a first portion of a fluid to the first outlet and divert a second portion of the fluid to the second outlet ; a first flow control member having a first cool fluid outlet and a second cool fluid outlet, wherein the first cool fluid outlet directs cool fluid to an atmosphere surrounding the housing , and wherein the second cool fluid outlet directs cool fluid to the first passageway to fluidly couple the first outlet to the housing to supply at least a portion of the first portion of the fluid directly to an internal cavity of the housing ; and a second flow control member having a first warm fluid outlet and a second warm fluid outlet, wherein the first warm fluid outlet directs warm fluid to an atmosphere surrounding the housing , and wherein the second warm fluid outlet directs warm fluid to the second passageway to fluidly couple the second outlet to the housing to supply at least a portion of the second portion of the fluid directly to the internal cavity of the housing separately from the first portion. <EOS>