Foundation of Refrigerator and Heat Pump(example for reverse heat engine)

The straight Carnot cycle has led to development of the automobiles that produce the work by absorbing heat from the source and liberating remaining heat to the atmosphere. The concept of reversed heat engine has led to the development of the refrigerator and heat pump. As we know our household refrigerator maintains low temperature inside the freezer by absorbing the heat from this low temperature compartment and liberating it to atmosphere which is at high temperature. For doing so the refrigerator consumes electricity, which is work input.The air-conditioner and heat pump also work on the same principle. During summers air-conditioner removes the heat from room and liberates it to the atmosphere thus keeping the room cool. The heat pump is useful in winters, it absorbs the heat from atmosphere, which is at low temperature and releases it to the room to keep it hot.The Carnot cycle and reversed Carnot cycle has led to the major developments in the human history. There is hardly any other cycle which can be as universally applicable as these two.