A Micro Photovoltaic-heat Pump System for House Heating by Radiant Floor: Some Experimental Results

A theoretical-experimental research has been carried out feeding a reversible air-water heat pump, 6 kW heating capacity, through a solar photovoltaic (PV) micro grid. The heat pump heated a laboratory which is used as a prototype for the study of solar heating systems. The PV field consists of 16 modules with an useful an total area of 18.7 and 21 m2, respectively. Each module, composed by 48 polycrystalline silicon cells of 0.02434 m2, has a nominal efficiency of 14% and peak power of 180 W. The PV system stores electricity in 250Ah batteries from where is converted from DC to AC through a 3.0 kW inverter which feeds the heat pump. It works supplying 840 l/h of hot water at 35-45 °C to the radiant floor. The data measuring system is recording variables such as solar radiation; temperatures; input power to batteries; heat produced by the heat pump and transferred by the radiant floor; heat pump's COP; solar fraction, etc. The objective of this work is to present and discuss the experimental results obtained during the period 10th-17th of February, 2013, including the detailed results of a representative day, 15/02/2013, using only PV source electricity.