Heating and Cooling with Focus on Increased Energy Efficiency and Improved Comfort

The Summary Report and Guidebook summarise the work of the LowEx cooperation. An other result of the LowEx cooperation was the funding of the International Society for Low Exergy Systems in Buildings (LowExNet). LowEx, the international research programme for Low Exergy Systems for Heating and Cooling of Buildings, is part of the International Energy Agency's (IEA) Implementing Agreement Energy Conservation in Buildings and Community Systems (ECBCS). The aim of the programme was to promote rational use of energy by encouraging the use of low temperature heating systems and high temperature cooling systems of buildings. These systems that are suitable for office buildings, service buildings and residential buildings, can use a variety of fuels and renewable energy sources. These systems use energy efficiently while providing a comfortable indoor climate. They should be widely implemented now in order to create a possibility to use sustainable energy sources in the near future. This publication is an official Annex report. The Summary Report summarises and presents the contents of the Guidebook, which is included here in CD-ROM format. The Guidebook is meant to help engineering offices, consultants and architects in their search for energy efficient heating and cooling systems that can provide the occupants with comfortable, clean and healthy environment. In addition, some background information is offered for real estate builders, building maintenance managers, political decision makers and the public at large. The Guidebook is also freely available on the internet (www.lowex.net). Exergy defines the quality of energy and is an important tool for designing and assessing different heating and cooling systems. Application of exergy analysis into buildings has not been common before the implementation of Annex 37. Tools for exergy analysis of buildings were developed during the working time of Annex 37 and are presented in the Summary Report and included in the CD-ROM Guidebook. Exergy analysis can also be applied to human body to find optimal thermal conditions. Studies show that the lowest human body exergy consumption occurs at thermally neutral condition. The findings suggest that we may be able to establish both thermal comfort and low-exergy consuming systems at the same time. The human body exergy analyses have now just started to articulate why low exergy systems are essential for creating rational and comfortable built environment. In Annex 37, 'low exergy (or LowEx) systems' are defined as heating or cooling systems that allow the use of low valued energy as the energy source. In practice, this means systems that provide heating or cooling energy at a temperature close to room temperature. There are currently many low exergy technologies available. Low temperature systems successfully combine both traditional and innovative new approaches to heating. Usually the heat is transferred into the room through air or liquid circulation systems and the same system can often be used for both heating and cooling. Research shows that people living in houses with low temperature heating systems are very satisfied with ambient indoor air quality. In particular, thermal comfort levels are considered to be higher than in houses with a traditional heating system. Residents also experienced a reduction in draughts and dust, and reported fresher air in houses with low temperature heating systems. The advantages and disadvantages, mentioned by the occupants in the survey conducted during Annex 37, are similar to results in the literature. Also experiences from the case studies supported the findings from literature and the occupants' survey. By using low temperature heating systems the room temperature can be decreased by a few degrees, which is more energy efficient and healthier for occupants. Low temperature