In advanced aerospace manufacturing, environmental stability is far more than a comfort requirement, it is a production necessity.
Many manufacturing processes rely on tightly controlled temperature and humidity conditions to ensure consistent product quality. Even small environmental fluctuations can influence material behaviour, manufacturing accuracy and process repeatability.
When one of the Air Handling Units serving a specialist aerospace production facility began struggling to maintain its strict environmental setpoints during unusually warm summer conditions, Air Handlers Northern Ltd called upon iACS to investigate.
Although the mechanical equipment had been correctly selected and installed, the facility experienced increasing room temperatures, extended dehumidification cycles and slower-than-expected environmental recovery.
Rather than recommending expensive mechanical upgrades, iACS carried out a detailed control strategy review, proving the mechanical plant was capable of delivering the required performance before optimising the software to unlock its full potential.
The result was a stable, highly responsive Air Handling Unit capable of consistently maintaining 20°C and 50% relative humidity, even during periods of elevated outdoor temperatures.
What This Project Covers
This project demonstrates how iACS delivered:
- Advanced AHU control optimisation
- P.I.D. loop tuning
- Dehumidification optimisation
- DX cooling integration
- Supply-air regulation
- Electric reheater optimisation
- Heat recovery optimisation
- Site troubleshooting
- Collaborative commissioning
- Application-specific HVAC controls
Table of Contents
- Project Overview
- Why Environmental Stability Matters in Aerospace Manufacturing
- The Air Handling Unit Configuration
- The Challenge During Summer Operation
- Understanding the Dehumidification Process
- Diagnosing the Real Cause
- Optimising the Control Strategy
- P.I.D. Loop Tuning
- Unlocking the Full Cooling Capacity
- Live Capacity Testing
- Final Commissioning & Performance Verification
- The Project Outcome
- Before and After the iACS Optimisation
- Why This Project Matters
- Key Capabilities Demonstrated
- Looking to Optimise Your AHU Controls?
1. Project Overview
Sector
Aerospace Manufacturing
Application
Precision Manufacturing Environment
Customer
Air Handlers Northern Ltd (AHN)
End User
A leading global aerospace manufacturer.
Facilities Management
JLL
Mechanical Contractor
Lancs Gas
Project Timeline
- Troubleshooting and optimisation: January – July 2026
- Final optimisation completed: July 2026
iACS Scope
- AHU controls optimisation
- P.I.D. loop tuning
- Site commissioning
- Control strategy redesign
- DX cooling optimisation
- Dehumidification optimisation
- Live performance testing
AHU Configuration
The Air Handling Unit incorporated:
- Mitsubishi DX cooling
- Electric reheater
- Condair RSII50 steam humidifier
- Heat recovery
- Dehumidification control
- iSMART control platform
Project Status
Successfully optimised and fully operational.
2. Why Environmental Stability Matters in Aerospace Manufacturing
Unlike many commercial HVAC applications, aerospace manufacturing often requires extremely stable environmental conditions.
Variations in temperature or humidity can influence:
- Material stability
- Manufacturing tolerances
- Product quality
- Process consistency
- Production reliability
The production area served by this AHU required the environment to remain at:
- 20°C
- 50% Relative Humidity
Maintaining these conditions continuously was essential for the manufacturing process.
3. The Air Handling Unit Configuration
The packaged AHU incorporated several environmental control systems working together.
These included:
DX Cooling
Twin Mitsubishi DX condensing units provided cooling and dehumidification.
Electric Heater
An electric reheater restored supply air temperature following dehumidification.
Steam Humidification
A Condair RSII50 humidifier maintained humidity during dry conditions.
Heat Recovery
The system recovered energy where appropriate to improve overall efficiency.
iSMART Controls
An iACS iSMART control platform coordinated the complete operating sequence.
4. The Challenge During Summer Operation
During a period of unusually warm weather, outside temperatures reached approximately 28°C.
The production area began drifting away from its environmental targets.
The site recorded:
- Room temperature increasing to approximately 24°C
- Extended dehumidification operation
- Electric heater operating against the cooling coil
- Slower response to changing heat loads
- Humidifier alarms
- Concerns regarding cooling performance
At first glance, the symptoms suggested insufficient cooling capacity.
However, iACS approached the issue differently.
5. Understanding the Dehumidification Process
Effective dehumidification requires the cooling coil to reduce air temperature below its dew point.
This removes moisture from the air before the electric reheater raises the supply air temperature back towards the required condition.
During this process:
- Cooling removes moisture.
- Heating restores supply temperature.
To an observer, it can appear that heating and cooling are working against one another.
In reality, both systems are performing different parts of the same humidity-control strategy.
The challenge lies in coordinating them correctly.
6. Diagnosing the Real Cause
Rather than immediately recommending larger cooling equipment, the iACS commissioning engineer carried out a systematic review.
The investigation confirmed:
- The DX cooling plant was operational.
- The electric reheater was operational.
- The humidifier was functioning.
- Mechanical capacity was available.
The issue was not the equipment.
It was the speed at which the control strategy responded.
The system was regulating temperature using the return-air sensor.
Because the return air reflected conditions only after they had travelled through the occupied space, the control response lagged behind the changing thermal load.
7. Optimising the Control Strategy
To improve responsiveness, iACS reconfigured the control philosophy.
Instead of regulating temperature from the return air, the system was changed to regulate using the supply-air temperature sensor.
This significantly reduced the response time.
Benefits included:
- Faster correction
- Reduced thermal lag
- Improved room stability
- Better temperature recovery
- More responsive environmental control
The return-air sensor remained valuable for monitoring overall room conditions while the supply-air sensor became the primary regulating reference.
8. P.I.D. Loop Tuning
The dehumidification P.I.D. loop was then refined.
The software was adjusted by:
- Tightening the humidity differential to 10% rH
- Reducing the integral time to 200 seconds
These changes allowed the control system to react more quickly to humidity changes while maintaining stable operation.
The revised tuning improved:
- Humidity recovery
- Temperature stability
- Overall responsiveness
9. Unlocking the Full Cooling Capacity
The original cooling cascade shared demand between:
- Heat recovery
- DX cooling
This delayed access to the full cooling capacity.
iACS modified the strategy so the DX cooling could operate over the full 0–100% demand range.
This ensured maximum cooling performance was immediately available whenever required.
The revised sequence allowed the system to respond much more effectively during periods of high ambient temperature.
10. Live Capacity Testing
Before completing the optimisation, iACS carried out live testing to prove the capability of the installed plant.
The DX cooling was manually forced to 100% demand.
The supply air temperature reduced to approximately:
6.7°C
The electric reheater was then forced to 100% output.
The supply air temperature recovered to approximately:
20.8°C
These tests confirmed that:
- The DX plant had sufficient cooling capacity.
- The electric reheater had sufficient heating capacity.
- The issue was software response, not mechanical performance.
By proving the available capacity, unnecessary mechanical modifications were avoided.
11. Final Commissioning & Performance Verification
Following the software modifications, the system underwent full commissioning.
The commissioning included:
- Temperature verification
- Humidity verification
- Cooling sequence testing
- Electric heater testing
- P.I.D. verification
- Dehumidification verification
- Live environmental monitoring
The revised strategy demonstrated stable operation throughout the testing period.
12. The Project Outcome
Following optimisation, the Air Handling Unit consistently maintained:
- 20°C
- 50% Relative Humidity
Even while external temperatures remained close to 28°C, the return-air temperature stabilised at approximately 20.8°C.
The facilities management team described the improvement as "massive."
Most importantly, the project achieved the required environmental performance without replacing mechanical equipment or increasing heating capacity.
13. Before and After the iACS Optimisation
| Before Optimisation | After iACS Optimisation |
| Room temperature reached approximately 24°C | Stable 20°C maintained |
| Extended dehumidification cycles | Faster humidity recovery |
| Return-air regulation | Supply-air regulation |
| Slow P.I.D. response | Optimised P.I.D. loops |
| Limited DX authority | Full 0–100% DX control |
| Mechanical upgrades considered | Software optimisation resolved issue |
14. Why This Project Matters
Many HVAC performance problems are incorrectly assumed to be mechanical.
This project demonstrates the importance of understanding the interaction between:
- Sensors
- Control algorithms
- P.I.D. tuning
- Heating
- Cooling
- Dehumidification
- Heat recovery
Rather than replacing equipment, iACS optimised the existing controls to unlock the performance already available within the system.
The result was a more responsive Air Handling Unit capable of maintaining the strict environmental conditions demanded by advanced aerospace manufacturing.
15. Key Capabilities Demonstrated
- AHU control optimisation
- Advanced P.I.D. tuning
- DX cooling integration
- Dehumidification control
- Electric reheater optimisation
- Supply-air control strategies
- Live capacity testing
- Site troubleshooting
- Collaborative commissioning
- Aerospace HVAC expertise
16. Looking to Optimise Your AHU Controls?
Even the best mechanical equipment cannot achieve its full potential without the right control strategy.
At iACS, we specialise in optimising Air Handling Unit performance through intelligent software, advanced commissioning and application-specific control strategies.
Our expertise includes:
- AHU controls
- P.I.D. optimisation
- Dehumidification strategies
- DX cooling integration
- Heat recovery control
- Humidity control
- Site troubleshooting
- Commissioning
- HVAC optimisation
Whether your application is aerospace, pharmaceuticals, healthcare, manufacturing or another critical environment, iACS can help unlock the full performance of your HVAC system.