ASHRAE - American Society of Heating@ Refrigerating and Air-Conditioning Engineers@ Inc.
Scope
"INTRODUCTION The existing building stock in European countries accounts for about 39% of final energy consumption in the European Union (EU) member states@ of which residential use represents 67% of total energy consumption in the buildings sector. In 2006@ the gross inland consumption in the EU-27 member states was 1825.2 million ton of oil equivalent (Mtoe)@ of which 129.7 Mtoe or 7.1% from renewables largely made of biomass (69%)@ hydro (20.5%)@ wind (5.5%)@ geothermal (4.3%) and only 0.8% for solar. The final energy consumption reached 1177.4 Mtoe@ of which 59.7 Mtoe or 5.1% from renewables excluding consumption for electricity and delivered heat@ and 9.2% including consumption of the energy branch for electricity and heat generation and distribution losses (EC 2009). Consequently@ efforts to reduce energy consumption in the building sector can constitute an important instrument in the efforts to alleviate the EU energy import dependency (currently at about 53.8% and may reach twothirds by 2030 (Capros et al. 2008) unless some urgent additional measures and policies are adopted) and comply with the Kyoto Protocol that came into effect on February 16@ 2004 to reduce carbon dioxide emissions by an overall 8% in the EU compared with 1990 values@ by 2012. This is also in accordance with the European Directive on the Energy Performance of Buildings??EPBD (2002/91/EC). Finally@ the European Directive on energy end-use efficiency and energy services (2006/32/EC amending Directive 93/76/EEC) to limit carbon dioxide emissions mandates that EU member states shall adopt and aim to achieve an overall national indicative energy savings target of 9% by 2017@ to be reached by way of energy services and other energy efficiency improvement measures. Details on all European Directives and EU law is available from the gateway to Community legislation online (EURLex). Along the same lines@ the European Parliament adopted in December 2008 a proposal for a new European Directive on the promotion of the use of energy from renewable sources. Accordingly@ each member state should increase its use of renewable energy sources (RES)??such as solar@ wind or hydro??in an effort to reach an ambitious 20% share of energy from renewable sources by 2020. Each EU member state will be required to increase its share of RES by 5.5% from 2005 levels@ with the remaining increase calculated on the basis of per capita gross domestic product@ for example@ to reach by 2020 a share of 10% in Malta up to 49% in Sweden. While the focus of the Directive is on the promotion of large scale renewable energy installations@ member states are nevertheless requested to use ""minimum levels for the use of energy from renewable sources in buildings"". Architects@ engineers and planners are also to benefit from member state ""guidance"" when planning new construction projects@ while local and regional administrative bodies should be recommended to ""ensure equipment and systems are installed for the use of heating@ cooling and electricity from RES@ and for district heating and cooling when planning@ designing@ building and refurbishing industrial or residential areas"". Under the new Directive@ EU member states must stipulate the ""use of minimum levels of energy from renewable sources in new buildings and in existing buildings that are subject to major renovation"". The city of Barcelona@ Spain has pioneered the mandatory use of renewables in building through its ""Solar Ordinance"". The ""Barcelona Model"" accelerates the penetration of solar thermal in the construction sector and several EU member states have already enacted such renewables obligations@ while even more regions and municipalities are adopting similar support measures. The EU final energy consumption for 2006 in the buildings sector (EC 2009) amounted to 455.2 Mtoe (38.7% of the total EU-27 final energy use)@ of which 304.9 Mtoe in residential (25.9%) and 150.3 Mtoe in non-residential (NR) buildings (12.8%). Residential energy demand is expected to rise by 12% between 2005 and 2030@ mainly as a result of the increasing number of residencies (+14% up to 2030)@ the growing degree of indoor comfort conditions and the important proliferation of electrical appliances and services (Capros et al. 2008). Energy demand in NR buildings is projected to grow at an annual rate of 0.9% in the period 2005-2030. Final energy consumed for residential space heating accounts for 66% of total energy used in the sector@ cooling for less than 1%@ but is projected to grow at a fast pace in the future@ water heating and cooking for 22%@ electrical appliances for 6%@ and lighting for 5%. For NR buildings@ space heating accounts for 50.5% and other heat uses (sanitary hot water and cooking) for 22.5%@ electrical appliances for 16.5%@ lighting for 4% and cooling for 6.5%. On the other hand@ more energy efficient building design@ better materials and construction practices@ and more energy efficient equipment and appliances (e.g.@ in 2004 the sales of certain high energy efficiency white appliances accounted for more than 70% of total sales)@ which are progressively being introduced to the market@ help alleviate some of the escalating trends for higher energy consumption. In this paper@ system characteristics@ benefits and obstacles from combined solar heating and cooling systems to achieve both high solar fractions and better financial performance are discussed. Existing solar combi (space heating and sanitary hot water)@ solar cooling and solar combi-plus (space heating and cooling@ and sanitary hot water) systems in Europe are reviewed@ providing a compilation of their main design@ operational and performance characteristics. Finally@ an overview of the ongoing work of a european research and demonstration project on high combi-plus systems identifies different technologies and components to optimize performance and reach high solar fractions."