- Controllability, in this context, is the ability of the system to be effectively controlled to provide stable, energy efficient, operation. Terminal units, etc. should also provide a comfortable
- Controllability of building services is poorly understood, most systems integrators and BMS manufacturers have little understanding of hydraulic design and thermodynamics, most building services
engineers do not have sufficient controls experience to understand how to design controllable systems. We can fill this gap in the design process.
- Many reported control problems are actually controllability problems. Controls are often blamed when systems do not work; yet often systems, particularly bivalent systems, are uncontrollable
or difficult to control due to plant characteristics, hydraulic design, etc. Plant manufacturers and specialist contractors guidance is often lacking (with some exceptions) as it normally aimed at
the relevant item of plant without consideration of overall system operation.
- During the development of CIBSE AM15 Biomass Heating a high proportion of standard schemes that were proposed by manufacturers and specialist contractors were found to have fundamental flaws that
affected overall system controllability.
- If the system is uncontrollable it does not matter how sophisticated the controls or BMS are, it will not work properly.
- Controllability was one of the principle causes of the 90% of systems that were not properly controlled costing £500million in additional energy costs, reported in 1994 in BRECSU General
Information Report 40 and is still included in current Carbon Trust Publications as a fact.
- Graham Smith has been analysing systems and resolving controllability problems for over thirty years and is amazed how poor some designs still are and how easily some of the problems could
have been avoided.