Energetic performance of different expansion valves in a supermarket

Adopting electronic expansion valves in the refrigerated display cabinets of many supermarkets enables an ap-preciable energy saving vis-à-vis the same installations equipped with thermostatic expansion valves. This is due to the fact that electronic valves enable a lower condensation pressure in the systems with air cooled condensers, which is adjusted to variations in outside air temperature. This paper reports the preliminary results of an inves-tigation conducted at a supermarket in central Italy where the display cabinets were operated alternately with thermostatic and electronic expansion valves. The switch from one type of valve to the other was scheduled on a daily basis. The preliminary results of a campaign of measurements that will extend from December 2004 to December 2005 show that using electronic valves at the supermarket in question gives rise to a mean saving on the electrical energy absorbed by the normal- and low-temperature compressors that varies between 20% and 35%, depending on the time of year.