If managed correctly – and there’s a lot of technical assumptions involved in the word ‘correctly’ – businesses could be looking at a five-fold decrease in the running costs of their building stock, writes Glen Irwin.
As lockdown continues, those of us in the built environment (and especially those of us with an interest in building optimisation) are asking questions of all those empty buildings. Are their systems still running with nobody in them? Have they been ‘closed down’ without really being ‘shut down’? Do they continue to utilise unnecessary energy, costing their owners money?
If we take a quick look at national, half-hourly grid electricity demand we can see a significant reduction, around 20%. However, this demand seems high given most of us are staying at home.
Many building operators will have employed established facilities management teams to close down their building stock, but the statistics indicate much more could be done to reduce energy consumption.
Is it likely that in the rush to close our offices, hotels, leisure centres and universities, the basics have been addressed; servers are still running, fire alarms and security systems are working, and someone continues to flush water systems to avoid legionella risks? And have further measures, requiring deeper, technical analysis, been missed? If so, building operators and tenants may be facing virtually the same energy bills during this period, whilst consuming energy unnecessarily. It is true that energy usage will naturally reduce, simply because occupants aren’t in the buildings, but we know more can be done with the right technical advice.
Let’s look at an example office building: owner-occupied, 4,000 sq m, air conditioned, based within a typical business park.
We can use prediction tools to break down actual annual energy use, cross-checked against real energy databases. If we look at a continued, drastic reduction in building utilisation for May, June and July, and adjust for seasonal weather differences, we can estimate the energy costs for three scenarios: normal usage before lockdown; unoccupied, naturally reduced usage with no interventions; and potential reductions with managed interventions.
This allows us to estimate three months of energy costs for each scenario as follows:
- Normal usage £55,200
- Unoccupied – no interventions £44,200
- Unoccupied – managed interventions £10,600
- Saving – over three months only £33,600
These kinds of savings can be achieved by shutting down or turning off most systems – whilst safeguarding risks.
It’s not as simple as just shutting everything off. The right solution needs a pragmatic engineering approach, and experience of operating buildings to truly consider and understand the impacts. However, the work required to achieve this can be delivered very rapidly: Touring empty buildings and surveying systems is low risk in terms of health and safety, and much of the work can be desk-based, including reviewing schematics, operation and maintenance manuals, and so on.
The key target areas of any building would include lighting, heating, air conditioning and ventilation systems. But lots of systems use power even when on standby. Some systems need a considered approach: pumps, kitchens, domestic water systems – simply turning everything off can end up with big repair bills and delays in opening buildings up again. Essential systems including life safety, security, IT and property protection systems must remain fully operational and unaffected, including the air conditioning systems serving these.
Crucially, the plan needs to work for when this is all over. Before the building is re-occupied the process needs to include a practical approach to starting things up again in a safe, controlled way.
Glen Irwin is technical director within Hydrock’s building performance engineering team.