Substantial reductions in building emission rate can be achieved by improving HVAC efficiency. The UK NCM System Data Wizard provides options for changing a range of system settings and parameters. For systems that are not covered there, it is permissible to enter appropriate parameters in the Apache System dialog, provided they can be justified on the basis of manufacturers’ data.
Fuel choice has a major effect on carbon dioxide emissions.
Specific fan power (SFP) is a parameter that has a significant effect on system performance. The Non-Domestic Heating, Cooling and Ventilation Compliance Guide defines requirements for a number of features including SFP. These are potentially onerous requirements that need to be taken into account from the start of projects. Designers need to be careful to allow large enough plant and riser space to ensure that these requirements can be met. Note that default values for SFP in the UK NCM System Data Wizard (which mirror those in iSBEM) tend to be somewhat high, often exceeding the requirements. These therefore need to be edited.
The ‘System adjustment’ and ‘Control corrections’ options in the wizard produce worthwhile improvements in performance.
DHW systems should be examined for efficiency opportunities.
