Domestic heating system with heat pump and supplementary electric heating

摘要

The heating system has the principal heating provided by a heat pump (1) and a supplementary heating unit (2). The heating is controlled by a programmable controller (3). The controller activates the heat pump and the supplementary heating unit in response to the electric power absorbed by the heat pump. The power absorbed by the heat pump is determined by a transducer measuring the current drawn by the electric motor in the heat pump. When this current exceeds a threshold the difference between the current and the threshold is used to determine the power that will be delivered to the electric resistance heating that provides the supplementary heating.