THERMAL PERFORMANCE OF A COMPACT SOLAR ASSISTED HEAT PUMP
2011 - PDF 0.25MB
Document Number: 2011.001
Heat Pumps to supply hot-water for domestic consumption are widely used especially in countries where electric energy is also employed for this purpose. Brazil is a country where most of the domestic hot-water requirements are supplied by electric energy, but basically it is done with electric showers. This solution, although cheap for the user in terms of initial investment, has a strong impact on the generation, transmission and distribution – GTD costs. Electric showers have an average power of more than 5 kW, and are a strong contribution to the residential electric energy end use (around 24% in Brazil (Procel/Eletrobras, 2007)). Also, they are partially responsible by the “peak hour” of the power consumption in the residential sector that occurs from 18:00 to 21:00 hours in Brazil. The consumption growth observed in the last years leads to a lack of reliability of the system, and energy efficiency measures are necessary to avoid risks and to postpone investments in GTD. Solar hot-water systems have been used as an effective way to mitigate the problems caused by the intensive use of electric showers, however, this solution faces some problems when used in low-income housing units: absence of hot-water piping, inadequate structure to install collectors and thermal storage, increase of specific thermal energy costs for small systems, and use of an electric shower as the backup system.