In accordance with Article 8.4.4.18 supply air systems for heating and cooling should be sized with temperature differences of 21°C and 11°C respectively (8.4.4.18.(2)). It also states that for systems 1-5 & 7 the supply air temperature should be reset according to the thermal blocks load and for system 6 the supply air temperature is constant at 13°C (8.4.4.18.(4)).
Finally, the NECB standard requires that for system 6 a minimum supply airflow rate of 2L/s per m2 be maintained during occupied periods (8.4.4.18.(4)).
In the ApacheHVAC NECB systems library the systems have been setup to take account of these requirements by default.
It should be noted that, as per 8.4.4.18 (5), where the proposed buildings secondary system contains fans of less than 10kW then the reference buildings secondary system should be modeled as having an identical fan power demand. If this applies, then a manual update is required by the user.
