Thermal distribution systems in small buildings are estimated to lose more than $10 billion worth of heating and cooling energy annually. ASHRAE established Standards Project Committee 152P, under the aegis of TC6.3, to develop a test method that could quantify the extent of these losses in individual homes. This test method has now completed its public comment period, and the committee is reviewing these comments.

There is a strong need to develop a more comprehensive specification of interactions between ducts and the rest of the building. The impact of duct energy losses on equipment efficiency is covered in the current version of Standard 152P, but in an approximate way. A refined analysis would not only impact the Standard but would be useful to builders and contractors in justifying optimal duct design and equipment specification. In particular, there is a strong relationship between duct design and optimal equipment sizing and airflow.

The objective of this research is to determine the functional forms of the equipment efficiency factors in Standard 152P and develop algorithms to quantify the impacts on duct efficiency of thermosiphoning, continuous fan operation, and zone control.

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