Photovoltaic Power for Walk-In Coolers

Summary

From a system analysis, the association of photovoltaic cells with motor compressors used in small industrial cold stores has been investigated by Séri Renault Ingénierie with financial support from the French Commissariat à l’Energie Solaire (COMES). With a view to assessing the market potential of photovoltaics for food conservation in hot climates and harsh environments stand-alone walk-in coolers have been studied and sized for:

• internal volumes ranging from 5 to 30 m³

• temperature levels between 0° C and 7° C.

The alternative DC versus AC supply for the motor compressor has been analyzed with respect to specifications of the location site envisaged — very remote without technical staff available. To reduce routine maintenance a fully hermetic AC motor-compressor has been chosen in preference to a DC “open” compressor. Consequently a high efficiency (>90%) PWM 3 — phase 3 kVA inverter has been developed. A 10 m³ capacity prototype powered by a 2.2 kW peak photovoltaic panel has been designed and is now being tested at Séri Renault’s headquarters — Bois d’Arcy (France). By Fall’ 82, prototype will be sent to an agricultural centre in Ouagadougou (Upper Volta) for field testing.