thermal efficiency

Over the last few decades, there is a clear target for reducing energy needs in the building sector. The above objective can be achieved both by renovating the existing building stock and/or by constructing new buildings that will meet the characteristics of zero or nearly zero energy buildings. In order to construct or renovate a building into a zero or almost zero energy building, different passive, active and hybrid systems can be used. One such system is a solar air heater collector.

Since 1970s, kinds of condensing boilers (CB) have been widely applied in HVAC engineering, theirexit flue gas temperature is very lower, even down to about 40?-45?, and their thermal efficiency isvery higher, even up to about 107%~109%, based on low heat value. The application of CBs in HVACsystem or hot water supply system can increase thermal efficiency and reduce the consumption of fuel,because of the utilization of latent heat of vapour in the exit flue gas.

Through the analysis of the main international environmental performance rating systems (BREEAM, LEED and GBTool) this work aims to show international design tendencies concerning sustainable building equipment requirements and to provide to designers and researchers a broad view of sustainable building equipment solutions. Hence a particular attention was paid to the assessment approach provided by these systems for each requirement, focussing on the comparison of the building performance to a benchmark, on compliance with qualitative indications or use of best technologies.