R. N. Farrugia1, C. Yousif1* and M. Villameriel Tejedor2

1 Institute for Energy Technology, University of Malta, Triq il-Barrakki, Marsaxlokk, MXK 1531, Malta 2 E. T.S. Ingenieros Industriales, Universidad de Valladolid, Paseo del Cauce, s/n 47005 Valladolid, Spain.

Corresponding Author, charles. yousif@um. edu. mt

Abstract

This paper describes the outcome of an energy audit that was carried out in a Maltese residence. Monitoring included all major electric appliances, artificial lighting, solar water heating, and indoor micro-climate conditions. Results showed that almost 40% of the electricity bill was attributed to the back-up heating element within the solar water heating system. Furthermore, a freezer and a fridge-freezer were found to operate continuously without stopping and were responsible for about 20% of the electricity bill. Appliances left in stand-by mode accounted for 10% of the bill. Only 13% of the light fixtures were energy efficient bulbs. Conclusions were that energy use at home was not only dependent on the efficiency of the appliances, but also on the lifestyle of their users, on their background knowledge of energy saving and on the level of their environmental awareness.

Keywords: solar water heating, energy audit, domestic, appliances.

1. Introduction

During the past 15 years, electricity consumption in Malta has been on the increase in spite of higher fuel prices, with maximum summer demand exceeding that of winter as of the year 2001 [1] . Moreover the gap between summer and winter electricity consumption is on the increase. Figure 1 shows electricity generation for four different years, where it is clear that the increase in electricity demand is also across all months and in all years and not for the summer period alone. Since 2001, the domestic sector has become the major consumer of electricity with a share of 36% (Year 2006), followed by the commercial sector at 32% and the industrial sector at 30%. The remaining 2% is attributed to street lighting [2] . Hence, it becomes increasingly important to explore ways and means of improving end-use energy efficiency in homes; bearing in mind the fact that this sector is also a major contributor to peak loads.

The home identified in this case study was situated in the locality of Swieqi, which may be described as an urban area with a high density of upmarket buildings. This project was initiated after the homeowner showed an interest to invest in renewable energy (RE) systems. Initial investigations identified high energy consumption rates — a situation that required redressing prior to the installation of any RE technologies. The dwelling consisted of a duplex — with a top floor apartment leading up to a penthouse. The apartment followed a fairly open plan design and comprised of a main living area with kitchen, laundry room / pantry, study and bedrooms. The penthouse consisted primarily of a lounge, conservatory, summer kitchen and patios.