BATON ROUGE - An air conditioning expert appointed by a federal judge has testified a portable air conditioner consisting of an ice chest, fan and duct has a high potential for success in helping to drop the extreme heat indexes on Louisiana's death row that threaten three ailing condemned killers.

Shane Hernandez, a professional engineer and A/C expert in Lafayette, told Chief U.S. District Judge Brian Jackson Monday the low-tech units placed outside the inmates' cells work.

Jackson ordered state corrections officials in December 2013 to prevent heat indexes - a measure of temperature and humidity - on death row at Louisiana State Penitentiary at Angola from topping 88 degrees.