Why and which insulation materials for refrigerators!

Abstract

Transmission is the major contributor (> 50%) to the total cooling load for typical domestic refrigerators. Understandably, insulation in refrigerator walls plays an important role in reducing it. In the present work, a system level computer model of domestic refrigerator has been developed and the effect of different insulation materials, with varying thickness, on the energy consumption, weight, inner-volume and payback periods investigated. The insulation materials studied include polyurethane (PU) foam and vacuum insulation panels (VIPs) made with fumed silica, glass fibre and alternative core materials. Optimum thickness of the insulation material for fridge and freezer were identified through a parametric sweep with an objective to minimize payback period. A fumed silica VIP insulated refrigerator is predicted to consume around 20% lesser energy over its lifetime, yield 148 litres extra storage volume and offer a payback period of 3 years relative to PU foam insulated refrigerator. Glass fibre VIP insulated refrigerator was found to have no payback because of their increased thermal conductivity due to ageing.