01 February 2020

Comfort & The Built Environment

Closed heating and chilled systems

Maintaining comfort conditions is an instinctive desire of human beings which began with the stone age man discovering fire and centuries later by the romans developing it into a science. Life on earth depends on heating and cooling to exist.

The human body functions at a peak efficiency between 16 and 22 degrees. It was no accident that the human body performs efficiently around the 21-degree isotherm. The more complex civilisation becomes the more sophisticated are the demands to control and maintain the environment in which we live and work.

Benefits to Client

Cost Efficiency – Energy out = energy in – losses

Due to its natural abundance and physical properties water remains today as the preferred energy transfer medium used in hydronic heating and cooling systems. How efficiently the systems operate can rely on two critical factors:

  • The quality and condition of the system water
  • The efficiency to provide heating or cooling where and when required.

SMSE can deliver the solutions that ensure hydronic [closed] heating and cooling systems can function efficiency to match the system design to provide the client with fit for purpose hydronic systems that are stable, accurate reliable safe and efficient.

  • Water treatment services that ensure the chemistry of the heat transfer medium achieves the requirements of the application
  • Commissioning and balancing of distribution pipework to provide an efficient regulated flow regime through each system.

Terminology for clarification

Open Systems

Exchange of energy and matter with the environment. Mass transfer occurs outside the thermodynamic envelope.

Domestic hot and cold water systems are examples of open systems.

Closed systems

Exchange of energy only with the environment. Mass transfer does not occur outside the thermodynamic envelope.

Hydronic heating and cooling systems are examples of closed systems.

Isolated systems

No exchange of energy or matter with the environment. Mass transfer or energy transfer does not occur outside the thermodynamic envelope.

A vacuum flask could be used as an example of an isolated system.

Closed System Water Treatment & Commissioning

Due to legislation in place and control measure required to ensure compliance, building operators and facilities managers are well aware of the problems encountered with bacteria in open system pipework and the control measures required. There is however much less understanding around closed system bacteria and the impact it can have.

This note give brief guidance on the on the types of bacteria commonly encountered in closed heating and chilled water cooling systems, the means of identification and control.

  • Effects of Bacteria in Closed System Pipework
  • Bacteria can cause several several problems including ;
  • Unrepeatable commissioning figures due to the generation of gases [ see Henrys Law ].
  • Corrossion

Energy Output = Energy Input – System Losses


The advancement of an installation from the state of static completion to full working that meet specified requirement.

Commissioning is paramount to achieving energy efficient systems and the ultimate test to ensuring a cost-effective built environment. Commissioning is a requirement in accordance with Part L of the Building Regulations. And is crucial for achieving safe, energy and carbon efficient hydronic systems through correct balancing and regulation of distribution circuits and system components.

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