Spotting Inefficiencies in your Energy Profile

An Energy Management System (EMS) is a versatile and powerful tool which helps visualise energy consumption and target areas for significant carbon reduction

Research has suggested that energy savings can account for 13% of total consumption on average. While an EMS has many added benefits, like visualising your carbon impact or bill reconciliation, the main payback lies with energy savings.

However, creating a plan for reducing energy can be overwhelming. A commonly asked question is, “How do I know if I am consuming too much?” 

The key is adopting a continuous process of engagement with the system. This article will highlight some techniques that can be used to help ‘Energy Champions’ spot inefficiencies and understand their energy profile.

High-level Information (Benchmarking)

One tried and tested method is to use comparative analysis. Comparing your energy use against other proven commodities will create a benchmark for performance.

The most common method is by normalising your annual consumption with a factor, to allow comparison against widely available benchmarks (for example, here) for a variety of building types.

The most common normalising factor is building size (floor area or room volume), creating a kWh/m2 Key Performance Indicator (KPI).

Understanding Your Data

Ensuring a full understanding of what data an EMS is collecting is imperative. The user of an EMS, or ‘Energy Champion’, must have full visibility of their site. This includes knowing the main pieces of energy-consuming equipment which relate to a data stream.

If you can visualise the equipment, you can create a view of the data more comprehensively and understand the trends. You can understand exactly what is being metered to allow you to reduce it.

Operational Hours

Once a user understands how their building compares to best practice, and which energy-consuming equipment they are collecting data for, the next step is to relate the data to site operations.

The most critical approach is to understand your operating hours. When a building is not occupied, or producing, there should be a reduction in consumption, as seen above (with some exceptions, such as external lighting).

If energy increases before operational hours or reduces after hours, then there is generally room for improvement.

Reducing Baseloads

Once you understand the operating hours, you can investigate the ‘out-of-hours’ energy consumption, otherwise known as the baseload demand (shown above in green).

This should be considerably lower than the operating demand and zero for many pieces of equipment (lighting, air conditioning, extractor fans).

If the baseload looks like a significant portion of the operating demand, you should look into switching off the equipment or varying control settings to take advantage of reduced occupancy. An example of this is AHU start up times, which are generally set conservatively.

Peaks and Troughs

Needless to say, spikes in your energy profile correspond to increased consumption, emissions and cost. Be sure to interrogate your systems to highlight these and speak to the responsible parties to ensure the peak is validated by a process (e.g., an increase in production, equipment start-up energy spike).

Highlighting Controls Inefficiencies

Optimising the controls on pieces of equipment is the final piece to the ongoing energy management puzzle. Poorly controlled equipment results in operating inefficiencies, again leading to increased consumption.

A common energy profile is the one seen above, where a piece of equipment is either cycling from a lower load to a higher load or on to off. Generally, this is not the designed operating procedure and should be queried.

In this case, it was found that the AHU’s PID controller was poorly tuned. Another common control issue is around heating or cooling systems that do not reduce consumption during the antagonistic season, e.g., a chiller controls should accommodate lower temperature during winter.

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