Energy efficiency of no-frost freezers

The importance of energy efficiency has an increasing trend as the energy resources are being depleted mainly because of the increasing population. Energy consumption is becoming important because energy resources on the earth are limited and existing resources run out of because of excess population growth, when environmental factors are taking into consideration. As a result of studies on energy consumption, the greatest ratio is determined to be about meeting domestic energy needs, right after industry energy needs. Refrigerators and freezers which are running continuously are appliances consuming the highest domestic energy. In this thesis, energy efficiency is investigated with the references of no-frost freezers in the A+ energy class. System components and refrigeration cycle of freezer are explained, information about standards on energy consumption testing is given, and the parameters affecting energy consumption of freezers are investigated. Investigation subjects are gathered in two main topics which are cabinet insulation of freezers and the optimization of refrigeration system components. A study has been conducted on insulation for freezers having two different heat gains which are used only polyurethane (PU) and PU with vacuum insulation panels in the reference cabin. In the thesis, appropriate insulation thicknesses are determined while keeping constant the external dimensions of freezer and investigating the effect of increase in PU insulation thickness to energy index. In the optimization of refrigeration systems components, alternative compressors which are able to meet freezer heat gain are compared in terms of energy consumption, then the information about refrigerant migration study is given. Air duct and the implementation of phase changing materials for the homogenization of temperature distribution of measurement packages in the freezer cabinet are explained for the optimization of the equipments in the refrigerating system.