This Publicly Available Specification (PAS) specifies a comprehensive set of test conditions for determining the heating and electrical
performance of heat-led micro-cogeneration packages that are primarily intended for use in dwellings. The PAS is suitable for testing those micro-cogeneration packages with a thermal output up
to 70 kW (252 MJ/hr); the full output test may also be suitable for packages up to 400 kW (1440 MJ/hr).
For the category of micro-cogeneration package that provides space and water heating in which the domestic hot water (DHW) is provided wholly from within the package (CombiPK), the DHW test conditions described in this PAS are only applicable for packages with less than 15 litres of water storage.
For CombiPK packages with hot water storage of 15 litres or more, the DHW test has not been yet been developed and this will be considered
for the next revision of the PAS. However, CombiPK packages with hot water storage of 15 litres or more can be tested using all other PAS 67 tests (full output, partial output and standby tests). The PAS results can be input to the procedure to calculate annual energy performance, such as “Method to evaluate the annual energy performance of
micro-cogeneration heating systems in dwellings” [2] which for these products, until the PAS is revised, treats the DHW load as additional
space heating load. This enables the estimation of the annual energy performance and derivation of the single index of performance for product comparison.
A reporting format for the test results is also specified.
NOTE PAS 67 is not intended to deliver an evaluation of the annual energy performance of a product directly, but provides the data from which it may be calculated. It is intended to produce test results and other information that can be used in a separate method of calculation of annual energy performance of the micro-cogeneration package. An estimate of annual energy performance is necessary for the SAP (The UK Government’s Standard Assessment Procedure for Energy Rating of Dwellings) [3] and other energy rating schemes. The document “Method to evaluate the annual energy performance of micro-cogeneration
heating systems in dwellings” [2] specifies such a method. An extension of the annual energy performance method is used to derive a single index of performance for product comparison, similar in principle to SEDBUK (Seasonal Efficiency of Domestic Boilers in the UK) [4] already used for boilers.