Heating films as an element of combined photovoltaic and heating systems in residential buildings

Abstract

This paper discusses the idea of combining a photovoltaic system with a heating film system to heat residential buildings. The analysis was performed for a newly built single-family house in Warsaw or its vicinity. The authors have selected the size of the photovoltaic installation, calculated the costs incurred by the user for the installation of a hybrid system, which were additionally compared to the cost of installing a gas installation (gas boiler) used for heating the building. The calculations were made for a single-family house with a usable area of 120 m 2 , the demand for utility energy for heating purposes in the newly built house was in the range of 10-50 kWh/m 2 /year. Based on the adopted parameters, the authors evaluated the economic efficiency of both investments (solutions) determining their net present values (NPV). The analysis takes the energy needed only for heating purposes into account. NPV for a heating system with a gas boiler with an investment outlay EUR 8,000 for buildings purchased for utility energy in the amount of 20 kWh/m 2 /year and the price for natural gas EUR 0.04 /kWh will be EUR -10,500 (for 15 years, discount rate r = 3%). For the same thermal needs (energy required) of the building, NPV for heating films + photovoltaic (HF + PV) will amount to -EUR 8,100. Comparing the variants will get a EUR 2,400 higher NPV for HF + PV. With a utility energy demand for heating purpose of 50 kWh/m 2 /year and gas heating installation investment cost of EUR 7,000, the NPV for both variants will be equal for natural gas price = EUR 0.035/kWh.