Guidebook for Energy Efficiency in Municipalities

money well spent. Structure contracts for design and commissioning so that part of the
payment depends on the system performing to specified standards after the building is
occupied. Designers might also be paid on the basis of system performance rather than a
percentage of system cost.
In addition, the HVAC designer has to consult with the building designer to ensure that
peak cooling and heating loads are minimised through good envelope design. This will
cut the capital cost of the HVAC system, and the peak energy charges.
Building management systems
Building management systems (also called building automation systems or simply BASs)
facilitate control and monitoring of equipment (especially air-conditioning and other
mechanical equipment). Such systems can have the advantages of:
improved control, comfort and security;
reduced equipment operating times, energy consumption and GHG emissions, and
reduced wear of the equipment;
improved monitoring of building and equipment, including running times, electricity
demand, temperatures, running costs, etc.
A BAS will have a capital cost of about € 120 per sensor or controlled point. The design of
a system (depending on what the user want it to do now and in the future) will require a
significant amount of time spent by staff and/or a consultant. BASs are sometimes
oversold - when they are credited with savings that could have been achieved more
economically by fixing existing simple controls.
When considering a BAS:
make sure that existing controls are optimised and that low-cost rectifications are
completed first;
consider what equipment needs controlling and what inputs will be used to decide if
and how the equipment will run;
write a technical description of the required BAS (possibly with assistance from inhouse
technical staff or independent consultant); this will help in clarifying the
requirements and communicate them to colleagues and potential suppliers.
When selecting a BAS it should be checked:
that the system permits flexibility and later expansion;
what happens to the system if some of the remote equipment fails;
that the system can be easily interrogated and reprogrammed by the organization’s
technical staff/team (without needing to refer to the installer or manufacturer);
that any new software or equipment introduced by the manufacturer will be made
compatible with all previous versions of software and equipment (preventing
premature obsolescence);
that international data formats are supported.
Estimating energy consumption and greenhouse emissions
Ideally, the energy use for HVAC should be separately metered. If this is the case, this
data can be easily converted to GHG emissions. If separate metered data are not
available, ‘house power’ may be separately metered. This includes HVAC, lighting of
common areas, lifts, etc. It may be possible to estimate electricity use for activities other
than HVAC, and subtract this from the ‘house power’ to give an estimate of HVAC
consumption. If only the whole building’s energy use is metered, this at least gives some
indication of HVAC energy consumption.