Executive summary
As refrigeration systems become more advanced, particularly with the adoption of transcritical CO₂, commissioning methods play an increasingly integral role in long-term performance.
One approach sometimes used is the introduction of “false loads”: artificial heat inputs designed to simulate refrigeration demand during commissioning or phased installations. While this method can appear to reduce upfront costs, it often introduces instability, inefficiency, and avoidable risk.
What is a false load?
A false load is an artificial heat source applied to a refrigeration system to simulate demand before real cases or fixtures are connected. In practice, this might take the form of electric heaters, either within glycol loops, space heating elements, or integrated into system components such as gas coolers.
The intention is straightforward: create enough load to allow the system to run and be commissioned without needing the full store or final application to be in place.
However, while these loads can imitate the presence of demand, they do not replicate the behavior of real refrigeration systems. Real loads fluctuate constantly, driven by customer interaction, ambient conditions, and operational cycles. False loads, by contrast, are inherently static and predictable.
This difference is at the core of the risks they introduce.
Why false loads create risk
The most significant issue with false loads is that they create a version of the system that does not exist in reality.
Modern CO₂ systems rely heavily on precise control strategies. When these systems are tuned against a stable, artificial load, they often perform well—initially. But once real refrigeration cases are introduced, the system is suddenly exposed to dynamic conditions it was never configured to handle. The result is instability: suction pressure fluctuations, control “hunting,” and a prolonged period of adjustment that can extend well beyond initial commissioning.
This mismatch also affects compressor health. CO₂ systems depend on correct mass flow to ensure oil returns reliably through the system. Artificial loads do not always generate the same flow characteristics as real evaporators, which can lead to oil logging or inconsistent return. Over time, this increases the likelihood of nuisance trips or, in more severe cases, compressor damage during the earliest phase of operation.
There is also a practical consequence that is often underestimated: systems commissioned with false loads rarely stay commissioned. Once the real load is introduced, engineers are effectively required to start again—retuning controls, troubleshooting instability, and addressing performance issues. What initially appears to be a shortcut becomes a duplicated effort, both in time and cost.
At a system level, false loads also make pressure management more difficult. Without a realistic and responsive load profile, controlling high-side pressure and flash gas behavior becomes far less predictable. This can lead to inefficient operation or, in some cases, pressure events that require intervention.
Beyond the technical considerations, false loads introduce inefficiencies that are harder to justify. They consume energy without delivering useful work, require additional space and installation effort, and add complexity to systems that are already increasingly sophisticated. In many environments, particularly urban or space-constrained locations, this added complexity becomes a tangible operational challenge.
Addressing the symptom, not the cause
In many cases, the need for a false load is not driven by commissioning requirements alone, but by limitations in system design.
Where refrigeration packs lack sufficient turndown capacity, or where compressor configurations are not well matched to the application, artificial loads are sometimes used to maintain stability. In these situations, the false load is effectively compensating for a system that cannot operate efficiently under low-load conditions.
Rather than resolving the underlying issue, this approach introduces an additional layer of complexity while leaving the root cause unaddressed.
More robust system design, particularly with adequate compressor staging and capacity control, can eliminate the need for artificial intervention altogether.
A more stable alternative: Real load commissioning
An alternative approach is to commission systems using real, temporary refrigeration loads rather than simulated ones.
By introducing temporary refrigeration capacity, such as rental systems, the plant operates under conditions that closely resemble its final environment. This means the load is dynamic, not static, and the system responds to real evaporator behavior rather than an artificial input.
The impact of this is significant. Control systems can be tuned accurately from the outset, reducing the need for later adjustments. Compressor operation aligns with real mass flow conditions, supporting proper oil return and long-term reliability. Pressure management becomes more predictable, as the system is responding to genuine load fluctuations rather than a fixed input.
Perhaps most importantly, commissioning becomes a single, continuous process rather than a staged one. The system that is handed over is the same system that was commissioned. Removing the need for rework, retuning, and extended troubleshooting.
There is also a fundamental efficiency advantage. Unlike false loads, which consume energy purely to simulate demand, real refrigeration capacity performs useful work. This removes the inefficiency inherent in artificial loading while simplifying the overall system setup.
Industry direction
In more mature refrigeration markets, the use of false loads has diminished over time. Improvements in case efficiency, system design, and compressor control have reduced the need for artificial stabilization methods.
Where additional functionality is required, such as space heating, dedicated systems have proven to be more efficient and effective than attempting to extract value from artificial loads.
The broader trend is clear: as systems become more advanced, commissioning practices are moving toward approaches that reflect real operating conditions rather than simulated ones.
Conclusion
False loads are often introduced as a practical solution to simplify commissioning or reduce upfront cost. In reality, they tend to create a disconnect between how a system is commissioned and how it ultimately operates.
This disconnect can lead to instability, increased wear on critical components, and additional labor that outweighs any initial savings.
Using real refrigeration loads during commissioning provides a more direct and reliable path. It aligns system behavior with real-world conditions from the beginning, reduces the need for rework, and supports long-term performance.
As refrigeration systems continue to evolve, the methods used to bring them into operation must evolve as well. Moving away from artificial load simulation is an important step toward more stable, efficient, and predictable outcomes.
