Annual energy consumption tells you how much energy a building uses. It does not tell you what energy infrastructure that building needs.
That distinction matters.
Two buildings can consume the same amount of energy over a year while placing very different demands on their heating, cooling and electrical infrastructure.
The difference is not simply how much energy they use. It is when they need it, how much they need at any one time and what is creating that demand.
The peak matters, but the reason behind it matters more
Consider two buildings with the same annual heating demand.
One has relatively steady demand throughout the day. The other operates at low demand for long periods before experiencing a significant peak on cold winter mornings.
On an annual energy report, they may look almost identical.
From an infrastructure perspective, they are not.
That peak can influence the size of heat pumps, electrical connections, transformers, thermal storage and backup plant. Designing around it without understanding what causes it can lead to unnecessary infrastructure and higher capital costs.
So identifying the peak is only the beginning.
What caused it?
Was it morning warm-up? Occupancy? Ventilation? Domestic hot water? An industrial process? Or several loads occurring simultaneously?
Once the cause is understood, the engineering options become clearer.
The peak may be reduced. It may be shifted. Thermal energy may be stored around it. Waste heat may be recovered elsewhere in the system. Despite popular belief – the answer is not always more capacity.
Design the infrastructure around the building
It becomes increasingly important to design the infrastructure around the building. Poor understanding of peak demand can translate directly into larger electrical connections, oversized plant and unnecessary infrastructure.
Geoenergy creates another set of possibilities.
The ground provides a stable thermal resource for both heating and cooling. Where buildings have simultaneous or complementary loads, energy can potentially be recovered and moved through the system rather than continually generated and rejected. Adding free cooling to this, even further opportunities to reduce electrical demand are created.
But geoenergy should not be the starting point.
The building should.
Infrastructure that lasts for decades
Good infrastructure design starts with understanding how the building actually operates. That means its load profile, operating hours, seasonal variation, heating and cooling peaks and the activities behind those peaks.
Annual consumption tells us how much. The load profile tells us when. Understanding the building tells us why.
Only then should we decide what infrastructure it needs.
Measure first. Design second. Build for decades.